1 files changed, 2663 insertions, 0 deletions

diff --git a/drivers/ieee1394/dv1394.c b/drivers/ieee1394/dv1394.c
new file mode 100644
index 000000000000..68c7a5f07842
--- /dev/null
+++ b/drivers/ieee1394/dv1394.c
@@ -0,0 +1,2663 @@
+/*
+ * dv1394.c - DV input/output over IEEE 1394 on OHCI chips
+ *   Copyright (C)2001 Daniel Maas <dmaas@dcine.com>
+ *     receive by Dan Dennedy <dan@dennedy.org>
+ *
+ * based on:
+ *  video1394.c - video driver for OHCI 1394 boards
+ *  Copyright (C)1999,2000 Sebastien Rougeaux <sebastien.rougeaux@anu.edu.au>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+/*
+  OVERVIEW
+
+  I designed dv1394 as a "pipe" that you can use to shoot DV onto a
+  FireWire bus. In transmission mode, dv1394 does the following:
+
+   1. accepts contiguous frames of DV data from user-space, via write()
+      or mmap() (see dv1394.h for the complete API)
+   2. wraps IEC 61883 packets around the DV data, inserting
+      empty synchronization packets as necessary
+   3. assigns accurate SYT timestamps to the outgoing packets
+   4. shoots them out using the OHCI card's IT DMA engine
+
+   Thanks to Dan Dennedy, we now have a receive mode that does the following:
+
+   1. accepts raw IEC 61883 packets from the OHCI card
+   2. re-assembles the DV data payloads into contiguous frames,
+      discarding empty packets
+   3. sends the DV data to user-space via read() or mmap()
+*/
+
+/*
+  TODO:
+
+  - tunable frame-drop behavior: either loop last frame, or halt transmission
+
+  - use a scatter/gather buffer for DMA programs (f->descriptor_pool)
+    so that we don't rely on allocating 64KB of contiguous kernel memory
+    via pci_alloc_consistent()
+
+  DONE:
+  - during reception, better handling of dropped frames and continuity errors
+  - during reception, prevent DMA from bypassing the irq tasklets
+  - reduce irq rate during reception (1/250 packets).
+  - add many more internal buffers during reception with scatter/gather dma.
+  - add dbc (continuity) checking on receive, increment status.dropped_frames
+    if not continuous.
+  - restart IT DMA after a bus reset
+  - safely obtain and release ISO Tx channels in cooperation with OHCI driver
+  - map received DIF blocks to their proper location in DV frame (ensure
+    recovery if dropped packet)
+  - handle bus resets gracefully (OHCI card seems to take care of this itself(!))
+  - do not allow resizing the user_buf once allocated; eliminate nuke_buffer_mappings
+  - eliminated #ifdef DV1394_DEBUG_LEVEL by inventing macros debug_printk and irq_printk
+  - added wmb() and mb() to places where PCI read/write ordering needs to be enforced
+  - set video->id correctly
+  - store video_cards in an array indexed by OHCI card ID, rather than a list
+  - implement DMA context allocation to cooperate with other users of the OHCI
+  - fix all XXX showstoppers
+  - disable IR/IT DMA interrupts on shutdown
+  - flush pci writes to the card by issuing a read
+  - devfs and character device dispatching (* needs testing with Linux 2.2.x)
+  - switch over to the new kernel DMA API (pci_map_*()) (* needs testing on platforms with IOMMU!)
+  - keep all video_cards in a list (for open() via chardev), set file->private_data = video
+  - dv1394_poll should indicate POLLIN when receiving buffers are available
+  - add proc fs interface to set cip_n, cip_d, syt_offset, and video signal
+  - expose xmit and recv as separate devices (not exclusive)
+  - expose NTSC and PAL as separate devices (can be overridden)
+
+*/
+
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/wait.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/pci.h>
+#include <linux/fs.h>
+#include <linux/poll.h>
+#include <linux/smp_lock.h>
+#include <linux/bitops.h>
+#include <asm/byteorder.h>
+#include <asm/atomic.h>
+#include <asm/io.h>
+#include <asm/uaccess.h>
+#include <linux/delay.h>
+#include <asm/pgtable.h>
+#include <asm/page.h>
+#include <linux/sched.h>
+#include <linux/types.h>
+#include <linux/vmalloc.h>
+#include <linux/string.h>
+#include <linux/ioctl32.h>
+#include <linux/compat.h>
+#include <linux/cdev.h>
+
+#include "ieee1394.h"
+#include "ieee1394_types.h"
+#include "nodemgr.h"
+#include "hosts.h"
+#include "ieee1394_core.h"
+#include "highlevel.h"
+#include "dv1394.h"
+#include "dv1394-private.h"
+
+#include "ohci1394.h"
+
+#ifndef virt_to_page
+#define virt_to_page(x) MAP_NR(x)
+#endif
+
+#ifndef vmalloc_32
+#define vmalloc_32(x) vmalloc(x)
+#endif
+
+
+/* DEBUG LEVELS:
+   0 - no debugging messages
+   1 - some debugging messages, but none during DMA frame transmission
+   2 - lots of messages, including during DMA frame transmission
+       (will cause undeflows if your machine is too slow!)
+*/
+
+#define DV1394_DEBUG_LEVEL 0
+
+/* for debugging use ONLY: allow more than one open() of the device */
+/* #define DV1394_ALLOW_MORE_THAN_ONE_OPEN 1 */
+
+#if DV1394_DEBUG_LEVEL >= 2
+#define irq_printk( args... ) printk( args )
+#else
+#define irq_printk( args... )
+#endif
+
+#if DV1394_DEBUG_LEVEL >= 1
+#define debug_printk( args... ) printk( args)
+#else
+#define debug_printk( args... )
+#endif
+
+/* issue a dummy PCI read to force the preceding write
+   to be posted to the PCI bus immediately */
+
+static inline void flush_pci_write(struct ti_ohci *ohci)
+{
+        mb();
+        reg_read(ohci, OHCI1394_IsochronousCycleTimer);
+}
+
+static void it_tasklet_func(unsigned long data);
+static void ir_tasklet_func(unsigned long data);
+
+#ifdef CONFIG_COMPAT
+static long dv1394_compat_ioctl(struct file *file, unsigned int cmd,
+                               unsigned long arg);
+#endif
+
+/* GLOBAL DATA */
+
+/* list of all video_cards */
+static LIST_HEAD(dv1394_cards);
+static DEFINE_SPINLOCK(dv1394_cards_lock);
+
+/* translate from a struct file* to the corresponding struct video_card* */
+
+static inline struct video_card* file_to_video_card(struct file *file)
+{
+        return (struct video_card*) file->private_data;
+}
+
+/*** FRAME METHODS *********************************************************/
+
+static void frame_reset(struct frame *f)
+{
+        f->state = FRAME_CLEAR;
+        f->done = 0;
+        f->n_packets = 0;
+        f->frame_begin_timestamp = NULL;
+        f->assigned_timestamp = 0;
+        f->cip_syt1 = NULL;
+        f->cip_syt2 = NULL;
+        f->mid_frame_timestamp = NULL;
+        f->frame_end_timestamp = NULL;
+        f->frame_end_branch = NULL;
+}
+
+static struct frame* frame_new(unsigned int frame_num, struct video_card *video)
+{
+        struct frame *f = kmalloc(sizeof(*f), GFP_KERNEL);
+        if (!f)
+                return NULL;
+
+        f->video = video;
+        f->frame_num = frame_num;
+
+        f->header_pool = pci_alloc_consistent(f->video->ohci->dev, PAGE_SIZE, &f->header_pool_dma);
+        if (!f->header_pool) {
+                printk(KERN_ERR "dv1394: failed to allocate CIP header pool\n");
+                kfree(f);
+                return NULL;
+        }
+
+        debug_printk("dv1394: frame_new: allocated CIP header pool at virt 0x%08lx (contig) dma 0x%08lx size %ld\n",
+                     (unsigned long) f->header_pool, (unsigned long) f->header_pool_dma, PAGE_SIZE);
+
+        f->descriptor_pool_size = MAX_PACKETS * sizeof(struct DMA_descriptor_block);
+        /* make it an even # of pages */
+        f->descriptor_pool_size += PAGE_SIZE - (f->descriptor_pool_size%PAGE_SIZE);
+
+        f->descriptor_pool = pci_alloc_consistent(f->video->ohci->dev,
+                                                  f->descriptor_pool_size,
+                                                  &f->descriptor_pool_dma);
+        if (!f->descriptor_pool) {
+                pci_free_consistent(f->video->ohci->dev, PAGE_SIZE, f->header_pool, f->header_pool_dma);
+                kfree(f);
+                return NULL;
+        }
+
+        debug_printk("dv1394: frame_new: allocated DMA program memory at virt 0x%08lx (contig) dma 0x%08lx size %ld\n",
+                     (unsigned long) f->descriptor_pool, (unsigned long) f->descriptor_pool_dma, f->descriptor_pool_size);
+
+        f->data = 0;
+        frame_reset(f);
+
+        return f;
+}
+
+static void frame_delete(struct frame *f)
+{
+        pci_free_consistent(f->video->ohci->dev, PAGE_SIZE, f->header_pool, f->header_pool_dma);
+        pci_free_consistent(f->video->ohci->dev, f->descriptor_pool_size, f->descriptor_pool, f->descriptor_pool_dma);
+        kfree(f);
+}
+
+
+
+
+/*
+   frame_prepare() - build the DMA program for transmitting
+
+   Frame_prepare() must be called OUTSIDE the video->spinlock.
+   However, frame_prepare() must still be serialized, so
+   it should be called WITH the video->sem taken.
+ */
+
+static void frame_prepare(struct video_card *video, unsigned int this_frame)
+{
+        struct frame *f = video->frames[this_frame];
+        int last_frame;
+
+        struct DMA_descriptor_block *block;
+        dma_addr_t block_dma;
+        struct CIP_header *cip;
+        dma_addr_t cip_dma;
+
+        unsigned int n_descriptors, full_packets, packets_per_frame, payload_size;
+
+        /* these flags denote packets that need special attention */
+        int empty_packet, first_packet, last_packet, mid_packet;
+
+        u32 *branch_address, *last_branch_address = NULL;
+        unsigned long data_p;
+        int first_packet_empty = 0;
+        u32 cycleTimer, ct_sec, ct_cyc, ct_off;
+        unsigned long irq_flags;
+
+        irq_printk("frame_prepare( %d ) ---------------------\n", this_frame);
+
+        full_packets = 0;
+
+
+
+        if (video->pal_or_ntsc == DV1394_PAL)
+                packets_per_frame = DV1394_PAL_PACKETS_PER_FRAME;
+        else
+                packets_per_frame = DV1394_NTSC_PACKETS_PER_FRAME;
+
+        while ( full_packets < packets_per_frame ) {
+                empty_packet = first_packet = last_packet = mid_packet = 0;
+
+                data_p = f->data + full_packets * 480;
+
+                /************************************************/
+                /* allocate a descriptor block and a CIP header */
+                /************************************************/
+
+                /* note: these should NOT cross a page boundary (DMA restriction) */
+
+                if (f->n_packets >= MAX_PACKETS) {
+                        printk(KERN_ERR "dv1394: FATAL ERROR: max packet count exceeded\n");
+                        return;
+                }
+
+                /* the block surely won't cross a page boundary,
+                   since an even number of descriptor_blocks fit on a page */
+                block = &(f->descriptor_pool[f->n_packets]);
+
+                /* DMA address of the block = offset of block relative
+                    to the kernel base address of the descriptor pool
+                    + DMA base address of the descriptor pool */
+                block_dma = ((unsigned long) block - (unsigned long) f->descriptor_pool) + f->descriptor_pool_dma;
+
+
+                /* the whole CIP pool fits on one page, so no worries about boundaries */
+                if ( ((unsigned long) &(f->header_pool[f->n_packets]) - (unsigned long) f->header_pool)
+                    > PAGE_SIZE) {
+                        printk(KERN_ERR "dv1394: FATAL ERROR: no room to allocate CIP header\n");
+                        return;
+                }
+
+                cip = &(f->header_pool[f->n_packets]);
+
+                /* DMA address of the CIP header = offset of cip
+                   relative to kernel base address of the header pool
+                   + DMA base address of the header pool */
+                cip_dma = (unsigned long) cip % PAGE_SIZE + f->header_pool_dma;
+
+                /* is this an empty packet? */
+
+                if (video->cip_accum > (video->cip_d - video->cip_n)) {
+                        empty_packet = 1;
+                        payload_size = 8;
+                        video->cip_accum -= (video->cip_d - video->cip_n);
+                } else {
+                        payload_size = 488;
+                        video->cip_accum += video->cip_n;
+                }
+
+                /* there are three important packets each frame:
+
+                   the first packet in the frame - we ask the card to record the timestamp when
+                                                   this packet is actually sent, so we can monitor
+                                                   how accurate our timestamps are. Also, the first
+                                                   packet serves as a semaphore to let us know that
+                                                   it's OK to free the *previous* frame's DMA buffer
+
+                   the last packet in the frame -  this packet is used to detect buffer underflows.
+                                                   if this is the last ready frame, the last DMA block
+                                                   will have a branch back to the beginning of the frame
+                                                   (so that the card will re-send the frame on underflow).
+                                                   if this branch gets taken, we know that at least one
+                                                   frame has been dropped. When the next frame is ready,
+                                                   the branch is pointed to its first packet, and the
+                                                   semaphore is disabled.
+
+                   a "mid" packet slightly before the end of the frame - this packet should trigger
+                                   an interrupt so we can go and assign a timestamp to the first packet
+                                   in the next frame. We don't use the very last packet in the frame
+                                   for this purpose, because that would leave very little time to set
+                                   the timestamp before DMA starts on the next frame.
+                */
+
+                if (f->n_packets == 0) {
+                        first_packet = 1;
+                } else if ( full_packets == (packets_per_frame-1) ) {
+                        last_packet = 1;
+                } else if (f->n_packets == packets_per_frame) {
+                        mid_packet = 1;
+                }
+
+
+                /********************/
+                /* setup CIP header */
+                /********************/
+
+                /* the timestamp will be written later from the
+                   mid-frame interrupt handler. For now we just
+                   store the address of the CIP header(s) that
+                   need a timestamp. */
+
+                /* first packet in the frame needs a timestamp */
+                if (first_packet) {
+                        f->cip_syt1 = cip;
+                        if (empty_packet)
+                                first_packet_empty = 1;
+
+                } else if (first_packet_empty && (f->n_packets == 1) ) {
+                        /* if the first packet was empty, the second
+                           packet's CIP header also needs a timestamp */
+                        f->cip_syt2 = cip;
+                }
+
+                fill_cip_header(cip,
+                                /* the node ID number of the OHCI card */
+                                reg_read(video->ohci, OHCI1394_NodeID) & 0x3F,
+                                video->continuity_counter,
+                                video->pal_or_ntsc,
+                                0xFFFF /* the timestamp is filled in later */);
+
+                /* advance counter, only for full packets */
+                if ( ! empty_packet )
+                        video->continuity_counter++;
+
+                /******************************/
+                /* setup DMA descriptor block */
+                /******************************/
+
+                /* first descriptor - OUTPUT_MORE_IMMEDIATE, for the controller's IT header */
+                fill_output_more_immediate( &(block->u.out.omi), 1, video->channel, 0, payload_size);
+
+                if (empty_packet) {
+                        /* second descriptor - OUTPUT_LAST for CIP header */
+                        fill_output_last( &(block->u.out.u.empty.ol),
+
+                                          /* want completion status on all interesting packets */
+                                          (first_packet || mid_packet || last_packet) ? 1 : 0,
+
+                                          /* want interrupts on all interesting packets */
+                                          (first_packet || mid_packet || last_packet) ? 1 : 0,
+
+                                          sizeof(struct CIP_header), /* data size */
+                                          cip_dma);
+
+                        if (first_packet)
+                                f->frame_begin_timestamp = &(block->u.out.u.empty.ol.q[3]);
+                        else if (mid_packet)
+                                f->mid_frame_timestamp = &(block->u.out.u.empty.ol.q[3]);
+                        else if (last_packet) {
+                                f->frame_end_timestamp = &(block->u.out.u.empty.ol.q[3]);
+                                f->frame_end_branch = &(block->u.out.u.empty.ol.q[2]);
+                        }
+
+                        branch_address = &(block->u.out.u.empty.ol.q[2]);
+                        n_descriptors = 3;
+                        if (first_packet)
+                                f->first_n_descriptors = n_descriptors;
+
+                } else { /* full packet */
+
+                        /* second descriptor - OUTPUT_MORE for CIP header */
+                        fill_output_more( &(block->u.out.u.full.om),
+                                          sizeof(struct CIP_header), /* data size */
+                                          cip_dma);
+
+
+                        /* third (and possibly fourth) descriptor - for DV data */
+                        /* the 480-byte payload can cross a page boundary; if so,
+                           we need to split it into two DMA descriptors */
+
+                        /* does the 480-byte data payload cross a page boundary? */
+                        if ( (PAGE_SIZE- ((unsigned long)data_p % PAGE_SIZE) ) < 480 ) {
+
+                                /* page boundary crossed */
+
+                                fill_output_more( &(block->u.out.u.full.u.cross.om),
+                                                  /* data size - how much of data_p fits on the first page */
+                                                  PAGE_SIZE - (data_p % PAGE_SIZE),
+
+                                                  /* DMA address of data_p */
+                                                  dma_region_offset_to_bus(&video->dv_buf,
+                                                                           data_p - (unsigned long) video->dv_buf.kvirt));
+
+                                fill_output_last( &(block->u.out.u.full.u.cross.ol),
+
+                                                  /* want completion status on all interesting packets */
+                                                  (first_packet || mid_packet || last_packet) ? 1 : 0,
+
+                                                  /* want interrupt on all interesting packets */
+                                                  (first_packet || mid_packet || last_packet) ? 1 : 0,
+
+                                                  /* data size - remaining portion of data_p */
+                                                  480 - (PAGE_SIZE - (data_p % PAGE_SIZE)),
+
+                                                  /* DMA address of data_p + PAGE_SIZE - (data_p % PAGE_SIZE) */
+                                                  dma_region_offset_to_bus(&video->dv_buf,
+                                                                           data_p + PAGE_SIZE - (data_p % PAGE_SIZE) - (unsigned long) video->dv_buf.kvirt));
+
+                                if (first_packet)
+                                        f->frame_begin_timestamp = &(block->u.out.u.full.u.cross.ol.q[3]);
+                                else if (mid_packet)
+                                        f->mid_frame_timestamp = &(block->u.out.u.full.u.cross.ol.q[3]);
+                                else if (last_packet) {
+                                        f->frame_end_timestamp = &(block->u.out.u.full.u.cross.ol.q[3]);
+                                        f->frame_end_branch = &(block->u.out.u.full.u.cross.ol.q[2]);
+                                }
+
+                                branch_address = &(block->u.out.u.full.u.cross.ol.q[2]);
+
+                                n_descriptors = 5;
+                                if (first_packet)
+                                        f->first_n_descriptors = n_descriptors;
+
+                                full_packets++;
+
+                        } else {
+                                /* fits on one page */
+
+                                fill_output_last( &(block->u.out.u.full.u.nocross.ol),
+
+                                                  /* want completion status on all interesting packets */
+                                                  (first_packet || mid_packet || last_packet) ? 1 : 0,
+
+                                                  /* want interrupt on all interesting packets */
+                                                  (first_packet || mid_packet || last_packet) ? 1 : 0,
+
+                                                  480, /* data size (480 bytes of DV data) */
+
+
+                                                  /* DMA address of data_p */
+                                                  dma_region_offset_to_bus(&video->dv_buf,
+                                                                           data_p - (unsigned long) video->dv_buf.kvirt));
+
+                                if (first_packet)
+                                        f->frame_begin_timestamp = &(block->u.out.u.full.u.nocross.ol.q[3]);
+                                else if (mid_packet)
+                                        f->mid_frame_timestamp = &(block->u.out.u.full.u.nocross.ol.q[3]);
+                                else if (last_packet) {
+                                        f->frame_end_timestamp = &(block->u.out.u.full.u.nocross.ol.q[3]);
+                                        f->frame_end_branch = &(block->u.out.u.full.u.nocross.ol.q[2]);
+                                }
+
+                                branch_address = &(block->u.out.u.full.u.nocross.ol.q[2]);
+
+                                n_descriptors = 4;
+                                if (first_packet)
+                                        f->first_n_descriptors = n_descriptors;
+
+                                full_packets++;
+                        }
+                }
+
+                /* link this descriptor block into the DMA program by filling in
+                   the branch address of the previous block */
+
+                /* note: we are not linked into the active DMA chain yet */
+
+                if (last_branch_address) {
+                        *(last_branch_address) = cpu_to_le32(block_dma | n_descriptors);
+                }
+
+                last_branch_address = branch_address;
+
+
+                f->n_packets++;
+
+        }
+
+        /* when we first assemble a new frame, set the final branch
+           to loop back up to the top */
+        *(f->frame_end_branch) = cpu_to_le32(f->descriptor_pool_dma | f->first_n_descriptors);
+
+        /* make the latest version of this frame visible to the PCI card */
+        dma_region_sync_for_device(&video->dv_buf, f->data - (unsigned long) video->dv_buf.kvirt, video->frame_size);
+
+        /* lock against DMA interrupt */
+        spin_lock_irqsave(&video->spinlock, irq_flags);
+
+        f->state = FRAME_READY;
+
+        video->n_clear_frames--;
+
+        last_frame = video->first_clear_frame - 1;
+        if (last_frame == -1)
+                last_frame = video->n_frames-1;
+
+        video->first_clear_frame = (video->first_clear_frame + 1) % video->n_frames;
+
+        irq_printk("   frame %d prepared, active_frame = %d, n_clear_frames = %d, first_clear_frame = %d\n last=%d\n",
+                   this_frame, video->active_frame, video->n_clear_frames, video->first_clear_frame, last_frame);
+
+        irq_printk("   begin_ts %08lx mid_ts %08lx end_ts %08lx end_br %08lx\n",
+                   (unsigned long) f->frame_begin_timestamp,
+                   (unsigned long) f->mid_frame_timestamp,
+                   (unsigned long) f->frame_end_timestamp,
+                   (unsigned long) f->frame_end_branch);
+
+        if (video->active_frame != -1) {
+
+                /* if DMA is already active, we are almost done */
+                /* just link us onto the active DMA chain */
+                if (video->frames[last_frame]->frame_end_branch) {
+                        u32 temp;
+
+                        /* point the previous frame's tail to this frame's head */
+                        *(video->frames[last_frame]->frame_end_branch) = cpu_to_le32(f->descriptor_pool_dma | f->first_n_descriptors);
+
+                        /* this write MUST precede the next one, or we could silently drop frames */
+                        wmb();
+
+                        /* disable the want_status semaphore on the last packet */
+                        temp = le32_to_cpu(*(video->frames[last_frame]->frame_end_branch - 2));
+                        temp &= 0xF7CFFFFF;
+                        *(video->frames[last_frame]->frame_end_branch - 2) = cpu_to_le32(temp);
+
+                        /* flush these writes to memory ASAP */
+                        flush_pci_write(video->ohci);
+
+                        /* NOTE:
+                           ideally the writes should be "atomic": if
+                           the OHCI card reads the want_status flag in
+                           between them, we'll falsely report a
+                           dropped frame. Hopefully this window is too
+                           small to really matter, and the consequence
+                           is rather harmless. */
+
+
+                        irq_printk("     new frame %d linked onto DMA chain\n", this_frame);
+
+                } else {
+                        printk(KERN_ERR "dv1394: last frame not ready???\n");
+                }
+
+        } else {
+
+                u32 transmit_sec, transmit_cyc;
+                u32 ts_cyc, ts_off;
+
+                /* DMA is stopped, so this is the very first frame */
+                video->active_frame = this_frame;
+
+                /* set CommandPtr to address and size of first descriptor block */
+                reg_write(video->ohci, video->ohci_IsoXmitCommandPtr,
+                          video->frames[video->active_frame]->descriptor_pool_dma |
+                          f->first_n_descriptors);
+
+                /* assign a timestamp based on the current cycle time...
+                   We'll tell the card to begin DMA 100 cycles from now,
+                   and assign a timestamp 103 cycles from now */
+
+                cycleTimer = reg_read(video->ohci, OHCI1394_IsochronousCycleTimer);
+
+                ct_sec = cycleTimer >> 25;
+                ct_cyc = (cycleTimer >> 12) & 0x1FFF;
+                ct_off = cycleTimer & 0xFFF;
+
+                transmit_sec = ct_sec;
+                transmit_cyc = ct_cyc + 100;
+
+                transmit_sec += transmit_cyc/8000;
+                transmit_cyc %= 8000;
+
+                ts_off = ct_off;
+                ts_cyc = transmit_cyc + 3;
+                ts_cyc %= 8000;
+
+                f->assigned_timestamp = (ts_cyc&0xF) << 12;
+
+                /* now actually write the timestamp into the appropriate CIP headers */
+                if (f->cip_syt1) {
+                        f->cip_syt1->b[6] = f->assigned_timestamp >> 8;
+                        f->cip_syt1->b[7] = f->assigned_timestamp & 0xFF;
+                }
+                if (f->cip_syt2) {
+                        f->cip_syt2->b[6] = f->assigned_timestamp >> 8;
+                        f->cip_syt2->b[7] = f->assigned_timestamp & 0xFF;
+                }
+
+                /* --- start DMA --- */
+
+                /* clear all bits in ContextControl register */
+
+                reg_write(video->ohci, video->ohci_IsoXmitContextControlClear, 0xFFFFFFFF);
+                wmb();
+
+                /* the OHCI card has the ability to start ISO transmission on a
+                   particular cycle (start-on-cycle). This way we can ensure that
+                   the first DV frame will have an accurate timestamp.
+
+                   However, start-on-cycle only appears to work if the OHCI card
+                   is cycle master! Since the consequences of messing up the first
+                   timestamp are minimal*, just disable start-on-cycle for now.
+
+                   * my DV deck drops the first few frames before it "locks in;"
+                     so the first frame having an incorrect timestamp is inconsequential.
+                */
+
+#if 0
+                reg_write(video->ohci, video->ohci_IsoXmitContextControlSet,
+                          (1 << 31) /* enable start-on-cycle */
+                          | ( (transmit_sec & 0x3) << 29)
+                          | (transmit_cyc << 16));
+                wmb();
+#endif
+
+                video->dma_running = 1;
+
+                /* set the 'run' bit */
+                reg_write(video->ohci, video->ohci_IsoXmitContextControlSet, 0x8000);
+                flush_pci_write(video->ohci);
+
+                /* --- DMA should be running now --- */
+
+                debug_printk("    Cycle = %4u ContextControl = %08x CmdPtr = %08x\n",
+                             (reg_read(video->ohci, OHCI1394_IsochronousCycleTimer) >> 12) & 0x1FFF,
+                             reg_read(video->ohci, video->ohci_IsoXmitContextControlSet),
+                             reg_read(video->ohci, video->ohci_IsoXmitCommandPtr));
+
+                debug_printk("    DMA start - current cycle %4u, transmit cycle %4u (%2u), assigning ts cycle %2u\n",
+                             ct_cyc, transmit_cyc, transmit_cyc & 0xF, ts_cyc & 0xF);
+
+#if DV1394_DEBUG_LEVEL >= 2
+                {
+                        /* check if DMA is really running */
+                        int i = 0;
+                        while (i < 20) {
+                                mb();
+                                mdelay(1);
+                                if (reg_read(video->ohci, video->ohci_IsoXmitContextControlSet) & (1 << 10)) {
+                                        printk("DMA ACTIVE after %d msec\n", i);
+                                        break;
+                                }
+                                i++;
+                        }
+
+                        printk("set = %08x, cmdPtr = %08x\n",
+                               reg_read(video->ohci, video->ohci_IsoXmitContextControlSet),
+                               reg_read(video->ohci, video->ohci_IsoXmitCommandPtr)
+                               );
+
+                        if ( ! (reg_read(video->ohci, video->ohci_IsoXmitContextControlSet) &  (1 << 10)) ) {
+                                printk("DMA did NOT go active after 20ms, event = %x\n",
+                                       reg_read(video->ohci, video->ohci_IsoXmitContextControlSet) & 0x1F);
+                        } else
+                                printk("DMA is RUNNING!\n");
+                }
+#endif
+
+        }
+
+
+        spin_unlock_irqrestore(&video->spinlock, irq_flags);
+}
+
+
+
+/*** RECEIVE FUNCTIONS *****************************************************/
+
+/*
+        frame method put_packet
+
+        map and copy the packet data to its location in the frame
+        based upon DIF section and sequence
+*/
+
+static void inline
+frame_put_packet (struct frame *f, struct packet *p)
+{
+        int section_type = p->data[0] >> 5;           /* section type is in bits 5 - 7 */
+        int dif_sequence = p->data[1] >> 4;           /* dif sequence number is in bits 4 - 7 */
+        int dif_block = p->data[2];
+
+        /* sanity check */
+        if (dif_sequence > 11 || dif_block > 149) return;
+
+        switch (section_type) {
+        case 0:           /* 1 Header block */
+                memcpy( (void *) f->data + dif_sequence * 150 * 80, p->data, 480);
+                break;
+
+        case 1:           /* 2 Subcode blocks */
+                memcpy( (void *) f->data + dif_sequence * 150 * 80 + (1 + dif_block) * 80, p->data, 480);
+                break;
+
+        case 2:           /* 3 VAUX blocks */
+                memcpy( (void *) f->data + dif_sequence * 150 * 80 + (3 + dif_block) * 80, p->data, 480);
+                break;
+
+        case 3:           /* 9 Audio blocks interleaved with video */
+                memcpy( (void *) f->data + dif_sequence * 150 * 80 + (6 + dif_block * 16) * 80, p->data, 480);
+                break;
+
+        case 4:           /* 135 Video blocks interleaved with audio */
+                memcpy( (void *) f->data + dif_sequence * 150 * 80 + (7 + (dif_block / 15) + dif_block) * 80, p->data, 480);
+                break;
+
+        default:           /* we can not handle any other data */
+                break;
+        }
+}
+
+
+static void start_dma_receive(struct video_card *video)
+{
+        if (video->first_run == 1) {
+                video->first_run = 0;
+
+                /* start DMA once all of the frames are READY */
+                video->n_clear_frames = 0;
+                video->first_clear_frame = -1;
+                video->current_packet = 0;
+                video->active_frame = 0;
+
+                /* reset iso recv control register */
+                reg_write(video->ohci, video->ohci_IsoRcvContextControlClear, 0xFFFFFFFF);
+                wmb();
+
+                /* clear bufferFill, set isochHeader and speed (0=100) */
+                reg_write(video->ohci, video->ohci_IsoRcvContextControlSet, 0x40000000);
+
+                /* match on all tags, listen on channel */
+                reg_write(video->ohci, video->ohci_IsoRcvContextMatch, 0xf0000000 | video->channel);
+
+                /* address and first descriptor block + Z=1 */
+                reg_write(video->ohci, video->ohci_IsoRcvCommandPtr,
+                          video->frames[0]->descriptor_pool_dma | 1); /* Z=1 */
+                wmb();
+
+                video->dma_running = 1;
+
+                /* run */
+                reg_write(video->ohci, video->ohci_IsoRcvContextControlSet, 0x8000);
+                flush_pci_write(video->ohci);
+
+                debug_printk("dv1394: DMA started\n");
+
+#if DV1394_DEBUG_LEVEL >= 2
+                {
+                        int i;
+
+                        for (i = 0; i < 1000; ++i) {
+                                mdelay(1);
+                                if (reg_read(video->ohci, video->ohci_IsoRcvContextControlSet) & (1 << 10)) {
+                                        printk("DMA ACTIVE after %d msec\n", i);
+                                        break;
+                                }
+                        }
+                        if ( reg_read(video->ohci, video->ohci_IsoRcvContextControlSet) &  (1 << 11) ) {
+                                printk("DEAD, event = %x\n",
+                                           reg_read(video->ohci, video->ohci_IsoRcvContextControlSet) & 0x1F);
+                        } else
+                                printk("RUNNING!\n");
+                }
+#endif
+        } else if ( reg_read(video->ohci, video->ohci_IsoRcvContextControlSet) &  (1 << 11) ) {
+                debug_printk("DEAD, event = %x\n",
+                             reg_read(video->ohci, video->ohci_IsoRcvContextControlSet) & 0x1F);
+
+                /* wake */
+                reg_write(video->ohci, video->ohci_IsoRcvContextControlSet, (1 << 12));
+        }
+}
+
+
+/*
+   receive_packets() - build the DMA program for receiving
+*/
+
+static void receive_packets(struct video_card *video)
+{
+        struct DMA_descriptor_block *block = NULL;
+        dma_addr_t block_dma = 0;
+        struct packet *data = NULL;
+        dma_addr_t data_dma = 0;
+        u32 *last_branch_address = NULL;
+        unsigned long irq_flags;
+        int want_interrupt = 0;
+        struct frame *f = NULL;
+        int i, j;
+
+        spin_lock_irqsave(&video->spinlock, irq_flags);
+
+        for (j = 0; j < video->n_frames; j++) {
+
+                /* connect frames */
+                if (j > 0 && f != NULL && f->frame_end_branch != NULL)
+                        *(f->frame_end_branch) = cpu_to_le32(video->frames[j]->descriptor_pool_dma | 1); /* set Z=1 */
+
+                f = video->frames[j];
+
+                for (i = 0; i < MAX_PACKETS; i++) {
+                        /* locate a descriptor block and packet from the buffer */
+                        block = &(f->descriptor_pool[i]);
+                        block_dma = ((unsigned long) block - (unsigned long) f->descriptor_pool) + f->descriptor_pool_dma;
+
+                        data = ((struct packet*)video->packet_buf.kvirt) + f->frame_num * MAX_PACKETS + i;
+                        data_dma = dma_region_offset_to_bus( &video->packet_buf,
+                                                             ((unsigned long) data - (unsigned long) video->packet_buf.kvirt) );
+
+                        /* setup DMA descriptor block */
+                        want_interrupt = ((i % (MAX_PACKETS/2)) == 0 || i == (MAX_PACKETS-1));
+                        fill_input_last( &(block->u.in.il), want_interrupt, 512, data_dma);
+
+                        /* link descriptors */
+                        last_branch_address = f->frame_end_branch;
+
+                        if (last_branch_address != NULL)
+                                *(last_branch_address) = cpu_to_le32(block_dma | 1); /* set Z=1 */
+
+                        f->frame_end_branch = &(block->u.in.il.q[2]);
+                }
+
+        } /* next j */
+
+        spin_unlock_irqrestore(&video->spinlock, irq_flags);
+
+}
+
+
+
+/*** MANAGEMENT FUNCTIONS **************************************************/
+
+static int do_dv1394_init(struct video_card *video, struct dv1394_init *init)
+{
+        unsigned long flags, new_buf_size;
+        int i;
+        u64 chan_mask;
+        int retval = -EINVAL;
+
+        debug_printk("dv1394: initialising %d\n", video->id);
+        if (init->api_version != DV1394_API_VERSION)
+                return -EINVAL;
+
+        /* first sanitize all the parameters */
+        if ( (init->n_frames < 2) || (init->n_frames > DV1394_MAX_FRAMES) )
+                return -EINVAL;
+
+        if ( (init->format != DV1394_NTSC) && (init->format != DV1394_PAL) )
+                return -EINVAL;
+
+        if ( (init->syt_offset == 0) || (init->syt_offset > 50) )
+                /* default SYT offset is 3 cycles */
+                init->syt_offset = 3;
+
+        if ( (init->channel > 63) || (init->channel < 0) )
+                init->channel = 63;
+
+        chan_mask = (u64)1 << init->channel;
+
+        /* calculate what size DMA buffer is needed */
+        if (init->format == DV1394_NTSC)
+                new_buf_size = DV1394_NTSC_FRAME_SIZE * init->n_frames;
+        else
+                new_buf_size = DV1394_PAL_FRAME_SIZE * init->n_frames;
+
+        /* round up to PAGE_SIZE */
+        if (new_buf_size % PAGE_SIZE) new_buf_size += PAGE_SIZE - (new_buf_size % PAGE_SIZE);
+
+        /* don't allow the user to allocate the DMA buffer more than once */
+        if (video->dv_buf.kvirt && video->dv_buf_size != new_buf_size) {
+                printk("dv1394: re-sizing the DMA buffer is not allowed\n");
+                return -EINVAL;
+        }
+
+        /* shutdown the card if it's currently active */
+        /* (the card should not be reset if the parameters are screwy) */
+
+        do_dv1394_shutdown(video, 0);
+
+        /* try to claim the ISO channel */
+        spin_lock_irqsave(&video->ohci->IR_channel_lock, flags);
+        if (video->ohci->ISO_channel_usage & chan_mask) {
+                spin_unlock_irqrestore(&video->ohci->IR_channel_lock, flags);
+                retval = -EBUSY;
+                goto err;
+        }
+        video->ohci->ISO_channel_usage |= chan_mask;
+        spin_unlock_irqrestore(&video->ohci->IR_channel_lock, flags);
+
+        video->channel = init->channel;
+
+        /* initialize misc. fields of video */
+        video->n_frames = init->n_frames;
+        video->pal_or_ntsc = init->format;
+
+        video->cip_accum = 0;
+        video->continuity_counter = 0;
+
+        video->active_frame = -1;
+        video->first_clear_frame = 0;
+        video->n_clear_frames = video->n_frames;
+        video->dropped_frames = 0;
+
+        video->write_off = 0;
+
+        video->first_run = 1;
+        video->current_packet = -1;
+        video->first_frame = 0;
+
+        if (video->pal_or_ntsc == DV1394_NTSC) {
+                video->cip_n = init->cip_n != 0 ? init->cip_n : CIP_N_NTSC;
+                video->cip_d = init->cip_d != 0 ? init->cip_d : CIP_D_NTSC;
+                video->frame_size = DV1394_NTSC_FRAME_SIZE;
+        } else {
+                video->cip_n = init->cip_n != 0 ? init->cip_n : CIP_N_PAL;
+                video->cip_d = init->cip_d != 0 ? init->cip_d : CIP_D_PAL;
+                video->frame_size = DV1394_PAL_FRAME_SIZE;
+        }
+
+        video->syt_offset = init->syt_offset;
+
+        /* find and claim DMA contexts on the OHCI card */
+
+        if (video->ohci_it_ctx == -1) {
+                ohci1394_init_iso_tasklet(&video->it_tasklet, OHCI_ISO_TRANSMIT,
+                                          it_tasklet_func, (unsigned long) video);
+
+                if (ohci1394_register_iso_tasklet(video->ohci, &video->it_tasklet) < 0) {
+                        printk(KERN_ERR "dv1394: could not find an available IT DMA context\n");
+                        retval = -EBUSY;
+                        goto err;
+                }
+
+                video->ohci_it_ctx = video->it_tasklet.context;
+                debug_printk("dv1394: claimed IT DMA context %d\n", video->ohci_it_ctx);
+        }
+
+        if (video->ohci_ir_ctx == -1) {
+                ohci1394_init_iso_tasklet(&video->ir_tasklet, OHCI_ISO_RECEIVE,
+                                          ir_tasklet_func, (unsigned long) video);
+
+                if (ohci1394_register_iso_tasklet(video->ohci, &video->ir_tasklet) < 0) {
+                        printk(KERN_ERR "dv1394: could not find an available IR DMA context\n");
+                        retval = -EBUSY;
+                        goto err;
+                }
+                video->ohci_ir_ctx = video->ir_tasklet.context;
+                debug_printk("dv1394: claimed IR DMA context %d\n", video->ohci_ir_ctx);
+        }
+
+        /* allocate struct frames */
+        for (i = 0; i < init->n_frames; i++) {
+                video->frames[i] = frame_new(i, video);
+
+                if (!video->frames[i]) {
+                        printk(KERN_ERR "dv1394: Cannot allocate frame structs\n");
+                        retval = -ENOMEM;
+                        goto err;
+                }
+        }
+
+        if (!video->dv_buf.kvirt) {
+                /* allocate the ringbuffer */
+                retval = dma_region_alloc(&video->dv_buf, new_buf_size, video->ohci->dev, PCI_DMA_TODEVICE);
+                if (retval)
+                        goto err;
+
+                video->dv_buf_size = new_buf_size;
+
+                debug_printk("dv1394: Allocated %d frame buffers, total %u pages (%u DMA pages), %lu bytes\n", 
+                             video->n_frames, video->dv_buf.n_pages,
+                             video->dv_buf.n_dma_pages, video->dv_buf_size);
+        }
+
+        /* set up the frame->data pointers */
+        for (i = 0; i < video->n_frames; i++)
+                video->frames[i]->data = (unsigned long) video->dv_buf.kvirt + i * video->frame_size;
+
+        if (!video->packet_buf.kvirt) {
+                /* allocate packet buffer */
+                video->packet_buf_size = sizeof(struct packet) * video->n_frames * MAX_PACKETS;
+                if (video->packet_buf_size % PAGE_SIZE)
+                        video->packet_buf_size += PAGE_SIZE - (video->packet_buf_size % PAGE_SIZE);
+
+                retval = dma_region_alloc(&video->packet_buf, video->packet_buf_size,
+                                          video->ohci->dev, PCI_DMA_FROMDEVICE);
+                if (retval)
+                        goto err;
+
+                debug_printk("dv1394: Allocated %d packets in buffer, total %u pages (%u DMA pages), %lu bytes\n",
+                                 video->n_frames*MAX_PACKETS, video->packet_buf.n_pages,
+                                 video->packet_buf.n_dma_pages, video->packet_buf_size);
+        }
+
+        /* set up register offsets for IT context */
+        /* IT DMA context registers are spaced 16 bytes apart */
+        video->ohci_IsoXmitContextControlSet = OHCI1394_IsoXmitContextControlSet+16*video->ohci_it_ctx;
+        video->ohci_IsoXmitContextControlClear = OHCI1394_IsoXmitContextControlClear+16*video->ohci_it_ctx;
+        video->ohci_IsoXmitCommandPtr = OHCI1394_IsoXmitCommandPtr+16*video->ohci_it_ctx;
+
+        /* enable interrupts for IT context */
+        reg_write(video->ohci, OHCI1394_IsoXmitIntMaskSet, (1 << video->ohci_it_ctx));
+        debug_printk("dv1394: interrupts enabled for IT context %d\n", video->ohci_it_ctx);
+
+        /* set up register offsets for IR context */
+        /* IR DMA context registers are spaced 32 bytes apart */
+        video->ohci_IsoRcvContextControlSet = OHCI1394_IsoRcvContextControlSet+32*video->ohci_ir_ctx;
+        video->ohci_IsoRcvContextControlClear = OHCI1394_IsoRcvContextControlClear+32*video->ohci_ir_ctx;
+        video->ohci_IsoRcvCommandPtr = OHCI1394_IsoRcvCommandPtr+32*video->ohci_ir_ctx;
+        video->ohci_IsoRcvContextMatch = OHCI1394_IsoRcvContextMatch+32*video->ohci_ir_ctx;
+
+        /* enable interrupts for IR context */
+        reg_write(video->ohci, OHCI1394_IsoRecvIntMaskSet, (1 << video->ohci_ir_ctx) );
+        debug_printk("dv1394: interrupts enabled for IR context %d\n", video->ohci_ir_ctx);
+
+        return 0;
+
+err:
+        do_dv1394_shutdown(video, 1);
+        return retval;
+}
+
+/* if the user doesn't bother to call ioctl(INIT) before starting
+   mmap() or read()/write(), just give him some default values */
+
+static int do_dv1394_init_default(struct video_card *video)
+{
+        struct dv1394_init init;
+
+        init.api_version = DV1394_API_VERSION;
+        init.n_frames = DV1394_MAX_FRAMES / 4;
+        /* the following are now set via devfs */
+        init.channel = video->channel;
+        init.format = video->pal_or_ntsc;
+        init.cip_n = video->cip_n;
+        init.cip_d = video->cip_d;
+        init.syt_offset = video->syt_offset;
+
+        return do_dv1394_init(video, &init);
+}
+
+/* do NOT call from interrupt context */
+static void stop_dma(struct video_card *video)
+{
+        unsigned long flags;
+        int i;
+
+        /* no interrupts */
+        spin_lock_irqsave(&video->spinlock, flags);
+
+        video->dma_running = 0;
+
+        if ( (video->ohci_it_ctx == -1) && (video->ohci_ir_ctx == -1) )
+                goto out;
+
+        /* stop DMA if in progress */
+        if ( (video->active_frame != -1) ||
+            (reg_read(video->ohci, video->ohci_IsoXmitContextControlClear) & (1 << 10)) ||
+            (reg_read(video->ohci, video->ohci_IsoRcvContextControlClear) &  (1 << 10)) ) {
+
+                /* clear the .run bits */
+                reg_write(video->ohci, video->ohci_IsoXmitContextControlClear, (1 << 15));
+                reg_write(video->ohci, video->ohci_IsoRcvContextControlClear, (1 << 15));
+                flush_pci_write(video->ohci);
+
+                video->active_frame = -1;
+                video->first_run = 1;
+
+                /* wait until DMA really stops */
+                i = 0;
+                while (i < 1000) {
+
+                        /* wait 0.1 millisecond */
+                        udelay(100);
+
+                        if ( (reg_read(video->ohci, video->ohci_IsoXmitContextControlClear) & (1 << 10)) ||
+                            (reg_read(video->ohci, video->ohci_IsoRcvContextControlClear)  & (1 << 10)) ) {
+                                /* still active */
+                                debug_printk("dv1394: stop_dma: DMA not stopped yet\n" );
+                                mb();
+                        } else {
+                                debug_printk("dv1394: stop_dma: DMA stopped safely after %d ms\n", i/10);
+                                break;
+                        }
+
+                        i++;
+                }
+
+                if (i == 1000) {
+                        printk(KERN_ERR "dv1394: stop_dma: DMA still going after %d ms!\n", i/10);
+                }
+        }
+        else
+                debug_printk("dv1394: stop_dma: already stopped.\n");
+
+out:
+        spin_unlock_irqrestore(&video->spinlock, flags);
+}
+
+
+
+static void do_dv1394_shutdown(struct video_card *video, int free_dv_buf)
+{
+        int i;
+
+        debug_printk("dv1394: shutdown...\n");
+
+        /* stop DMA if in progress */
+        stop_dma(video);
+
+        /* release the DMA contexts */
+        if (video->ohci_it_ctx != -1) {
+                video->ohci_IsoXmitContextControlSet = 0;
+                video->ohci_IsoXmitContextControlClear = 0;
+                video->ohci_IsoXmitCommandPtr = 0;
+
+                /* disable interrupts for IT context */
+                reg_write(video->ohci, OHCI1394_IsoXmitIntMaskClear, (1 << video->ohci_it_ctx));
+
+                /* remove tasklet */
+                ohci1394_unregister_iso_tasklet(video->ohci, &video->it_tasklet);
+                debug_printk("dv1394: IT context %d released\n", video->ohci_it_ctx);
+                video->ohci_it_ctx = -1;
+        }
+
+        if (video->ohci_ir_ctx != -1) {
+                video->ohci_IsoRcvContextControlSet = 0;
+                video->ohci_IsoRcvContextControlClear = 0;
+                video->ohci_IsoRcvCommandPtr = 0;
+                video->ohci_IsoRcvContextMatch = 0;
+
+                /* disable interrupts for IR context */
+                reg_write(video->ohci, OHCI1394_IsoRecvIntMaskClear, (1 << video->ohci_ir_ctx));
+
+                /* remove tasklet */
+                ohci1394_unregister_iso_tasklet(video->ohci, &video->ir_tasklet);
+                debug_printk("dv1394: IR context %d released\n", video->ohci_ir_ctx);
+                video->ohci_ir_ctx = -1;
+        }
+
+        /* release the ISO channel */
+        if (video->channel != -1) {
+                u64 chan_mask;
+                unsigned long flags;
+
+                chan_mask = (u64)1 << video->channel;
+
+                spin_lock_irqsave(&video->ohci->IR_channel_lock, flags);
+                video->ohci->ISO_channel_usage &= ~(chan_mask);
+                spin_unlock_irqrestore(&video->ohci->IR_channel_lock, flags);
+
+                video->channel = -1;
+        }
+
+        /* free the frame structs */
+        for (i = 0; i < DV1394_MAX_FRAMES; i++) {
+                if (video->frames[i])
+                        frame_delete(video->frames[i]);
+                video->frames[i] = NULL;
+        }
+
+        video->n_frames = 0;
+
+        /* we can't free the DMA buffer unless it is guaranteed that
+           no more user-space mappings exist */
+
+        if (free_dv_buf) {
+                dma_region_free(&video->dv_buf);
+                video->dv_buf_size = 0;
+        }
+
+        /* free packet buffer */
+        dma_region_free(&video->packet_buf);
+        video->packet_buf_size = 0;
+
+        debug_printk("dv1394: shutdown OK\n");
+}
+
+/*
+       **********************************
+       *** MMAP() THEORY OF OPERATION ***
+       **********************************
+
+        The ringbuffer cannot be re-allocated or freed while
+        a user program maintains a mapping of it. (note that a mapping
+        can persist even after the device fd is closed!)
+
+        So, only let the user process allocate the DMA buffer once.
+        To resize or deallocate it, you must close the device file
+        and open it again.
+
+        Previously Dan M. hacked out a scheme that allowed the DMA
+        buffer to change by forcefully unmapping it from the user's
+        address space. It was prone to error because it's very hard to
+        track all the places the buffer could have been mapped (we
+        would have had to walk the vma list of every process in the
+        system to be sure we found all the mappings!). Instead, we
+        force the user to choose one buffer size and stick with
+        it. This small sacrifice is worth the huge reduction in
+        error-prone code in dv1394.
+*/
+
+static int dv1394_mmap(struct file *file, struct vm_area_struct *vma)
+{
+        struct video_card *video = file_to_video_card(file);
+        int retval = -EINVAL;
+
+        /* serialize mmap */
+        down(&video->sem);
+
+        if ( ! video_card_initialized(video) ) {
+                retval = do_dv1394_init_default(video);
+                if (retval)
+                        goto out;
+        }
+
+        retval = dma_region_mmap(&video->dv_buf, file, vma);
+out:
+        up(&video->sem);
+        return retval;
+}
+
+/*** DEVICE FILE INTERFACE *************************************************/
+
+/* no need to serialize, multiple threads OK */
+static unsigned int dv1394_poll(struct file *file, struct poll_table_struct *wait)
+{
+        struct video_card *video = file_to_video_card(file);
+        unsigned int mask = 0;
+        unsigned long flags;
+
+        poll_wait(file, &video->waitq, wait);
+
+        spin_lock_irqsave(&video->spinlock, flags);
+        if ( video->n_frames == 0 ) {
+
+        } else if ( video->active_frame == -1 ) {
+                /* nothing going on */
+                mask |= POLLOUT;
+        } else {
+                /* any clear/ready buffers? */
+                if (video->n_clear_frames >0)
+                        mask |= POLLOUT | POLLIN;
+        }
+        spin_unlock_irqrestore(&video->spinlock, flags);
+
+        return mask;
+}
+
+static int dv1394_fasync(int fd, struct file *file, int on)
+{
+        /* I just copied this code verbatim from Alan Cox's mouse driver example
+           (Documentation/DocBook/) */
+
+        struct video_card *video = file_to_video_card(file);
+
+        int retval = fasync_helper(fd, file, on, &video->fasync);
+
+        if (retval < 0)
+                return retval;
+        return 0;
+}
+
+static ssize_t dv1394_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
+{
+        struct video_card *video = file_to_video_card(file);
+        DECLARE_WAITQUEUE(wait, current);
+        ssize_t ret;
+        size_t cnt;
+        unsigned long flags;
+        int target_frame;
+
+        /* serialize this to prevent multi-threaded mayhem */
+        if (file->f_flags & O_NONBLOCK) {
+                if (down_trylock(&video->sem))
+                        return -EAGAIN;
+        } else {
+                if (down_interruptible(&video->sem))
+                        return -ERESTARTSYS;
+        }
+
+        if ( !video_card_initialized(video) ) {
+                ret = do_dv1394_init_default(video);
+                if (ret) {
+                        up(&video->sem);
+                        return ret;
+                }
+        }
+
+        ret = 0;
+        add_wait_queue(&video->waitq, &wait);
+
+        while (count > 0) {
+
+                /* must set TASK_INTERRUPTIBLE *before* checking for free
+                   buffers; otherwise we could miss a wakeup if the interrupt
+                   fires between the check and the schedule() */
+
+                set_current_state(TASK_INTERRUPTIBLE);
+
+                spin_lock_irqsave(&video->spinlock, flags);
+
+                target_frame = video->first_clear_frame;
+
+                spin_unlock_irqrestore(&video->spinlock, flags);
+
+                if (video->frames[target_frame]->state == FRAME_CLEAR) {
+
+                        /* how much room is left in the target frame buffer */
+                        cnt = video->frame_size - (video->write_off - target_frame * video->frame_size);
+
+                } else {
+                        /* buffer is already used */
+                        cnt = 0;
+                }
+
+                if (cnt > count)
+                        cnt = count;
+
+                if (cnt <= 0) {
+                        /* no room left, gotta wait */
+                        if (file->f_flags & O_NONBLOCK) {
+                                if (!ret)
+                                        ret = -EAGAIN;
+                                break;
+                        }
+                        if (signal_pending(current)) {
+                                if (!ret)
+                                        ret = -ERESTARTSYS;
+                                break;
+                        }
+
+                        schedule();
+
+                        continue; /* start over from 'while(count > 0)...' */
+                }
+
+                if (copy_from_user(video->dv_buf.kvirt + video->write_off, buffer, cnt)) {
+                        if (!ret)
+                                ret = -EFAULT;
+                        break;
+                }
+
+                video->write_off = (video->write_off + cnt) % (video->n_frames * video->frame_size);
+
+                count -= cnt;
+                buffer += cnt;
+                ret += cnt;
+
+                if (video->write_off == video->frame_size * ((target_frame + 1) % video->n_frames))
+                                frame_prepare(video, target_frame);
+        }
+
+        remove_wait_queue(&video->waitq, &wait);
+        set_current_state(TASK_RUNNING);
+        up(&video->sem);
+        return ret;
+}
+
+
+static ssize_t dv1394_read(struct file *file,  char __user *buffer, size_t count, loff_t *ppos)
+{
+        struct video_card *video = file_to_video_card(file);
+        DECLARE_WAITQUEUE(wait, current);
+        ssize_t ret;
+        size_t cnt;
+        unsigned long flags;
+        int target_frame;
+
+        /* serialize this to prevent multi-threaded mayhem */
+        if (file->f_flags & O_NONBLOCK) {
+                if (down_trylock(&video->sem))
+                        return -EAGAIN;
+        } else {
+                if (down_interruptible(&video->sem))
+                        return -ERESTARTSYS;
+        }
+
+        if ( !video_card_initialized(video) ) {
+                ret = do_dv1394_init_default(video);
+                if (ret) {
+                        up(&video->sem);
+                        return ret;
+                }
+                video->continuity_counter = -1;
+
+                receive_packets(video);
+
+                start_dma_receive(video);
+        }
+
+        ret = 0;
+        add_wait_queue(&video->waitq, &wait);
+
+        while (count > 0) {
+
+                /* must set TASK_INTERRUPTIBLE *before* checking for free
+                   buffers; otherwise we could miss a wakeup if the interrupt
+                   fires between the check and the schedule() */
+
+                set_current_state(TASK_INTERRUPTIBLE);
+
+                spin_lock_irqsave(&video->spinlock, flags);
+
+                target_frame = video->first_clear_frame;
+
+                spin_unlock_irqrestore(&video->spinlock, flags);
+
+                if (target_frame >= 0 &&
+                        video->n_clear_frames > 0 &&
+                        video->frames[target_frame]->state == FRAME_CLEAR) {
+
+                        /* how much room is left in the target frame buffer */
+                        cnt = video->frame_size - (video->write_off - target_frame * video->frame_size);
+
+                } else {
+                        /* buffer is already used */
+                        cnt = 0;
+                }
+
+                if (cnt > count)
+                        cnt = count;
+
+                if (cnt <= 0) {
+                        /* no room left, gotta wait */
+                        if (file->f_flags & O_NONBLOCK) {
+                                if (!ret)
+                                        ret = -EAGAIN;
+                                break;
+                        }
+                        if (signal_pending(current)) {
+                                if (!ret)
+                                        ret = -ERESTARTSYS;
+                                break;
+                        }
+
+                        schedule();
+
+                        continue; /* start over from 'while(count > 0)...' */
+                }
+
+                if (copy_to_user(buffer, video->dv_buf.kvirt + video->write_off, cnt)) {
+                                if (!ret)
+                                        ret = -EFAULT;
+                                break;
+                }
+
+                video->write_off = (video->write_off + cnt) % (video->n_frames * video->frame_size);
+
+                count -= cnt;
+                buffer += cnt;
+                ret += cnt;
+
+                if (video->write_off == video->frame_size * ((target_frame + 1) % video->n_frames)) {
+                        spin_lock_irqsave(&video->spinlock, flags);
+                        video->n_clear_frames--;
+                        video->first_clear_frame = (video->first_clear_frame + 1) % video->n_frames;
+                        spin_unlock_irqrestore(&video->spinlock, flags);
+                }
+        }
+
+        remove_wait_queue(&video->waitq, &wait);
+        set_current_state(TASK_RUNNING);
+        up(&video->sem);
+        return ret;
+}
+
+
+/*** DEVICE IOCTL INTERFACE ************************************************/
+
+static long dv1394_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+        struct video_card *video;
+        unsigned long flags;
+        int ret = -EINVAL;
+        void __user *argp = (void __user *)arg;
+
+        DECLARE_WAITQUEUE(wait, current);
+
+        lock_kernel();
+        video = file_to_video_card(file);
+
+        /* serialize this to prevent multi-threaded mayhem */
+        if (file->f_flags & O_NONBLOCK) {
+                if (down_trylock(&video->sem)) {
+                        unlock_kernel();
+                        return -EAGAIN;
+                }
+        } else {
+                if (down_interruptible(&video->sem)) {
+                        unlock_kernel();
+                        return -ERESTARTSYS;
+                }
+        }
+
+        switch(cmd)
+        {
+        case DV1394_IOC_SUBMIT_FRAMES: {
+                unsigned int n_submit;
+
+                if ( !video_card_initialized(video) ) {
+                        ret = do_dv1394_init_default(video);
+                        if (ret)
+                                goto out;
+                }
+
+                n_submit = (unsigned int) arg;
+
+                if (n_submit > video->n_frames) {
+                        ret = -EINVAL;
+                        goto out;
+                }
+
+                while (n_submit > 0) {
+
+                        add_wait_queue(&video->waitq, &wait);
+                        set_current_state(TASK_INTERRUPTIBLE);
+
+                        spin_lock_irqsave(&video->spinlock, flags);
+
+                        /* wait until video->first_clear_frame is really CLEAR */
+                        while (video->frames[video->first_clear_frame]->state != FRAME_CLEAR) {
+
+                                spin_unlock_irqrestore(&video->spinlock, flags);
+
+                                if (signal_pending(current)) {
+                                        remove_wait_queue(&video->waitq, &wait);
+                                        set_current_state(TASK_RUNNING);
+                                        ret = -EINTR;
+                                        goto out;
+                                }
+
+                                schedule();
+                                set_current_state(TASK_INTERRUPTIBLE);
+
+                                spin_lock_irqsave(&video->spinlock, flags);
+                        }
+                        spin_unlock_irqrestore(&video->spinlock, flags);
+
+                        remove_wait_queue(&video->waitq, &wait);
+                        set_current_state(TASK_RUNNING);
+
+                        frame_prepare(video, video->first_clear_frame);
+
+                        n_submit--;
+                }
+
+                ret = 0;
+                break;
+        }
+
+        case DV1394_IOC_WAIT_FRAMES: {
+                unsigned int n_wait;
+
+                if ( !video_card_initialized(video) ) {
+                        ret = -EINVAL;
+                        goto out;
+                }
+
+                n_wait = (unsigned int) arg;
+
+                /* since we re-run the last frame on underflow, we will
+                   never actually have n_frames clear frames; at most only
+                   n_frames - 1 */
+
+                if (n_wait > (video->n_frames-1) ) {
+                        ret = -EINVAL;
+                        goto out;
+                }
+
+                add_wait_queue(&video->waitq, &wait);
+                set_current_state(TASK_INTERRUPTIBLE);
+
+                spin_lock_irqsave(&video->spinlock, flags);
+
+                while (video->n_clear_frames < n_wait) {
+
+                        spin_unlock_irqrestore(&video->spinlock, flags);
+
+                        if (signal_pending(current)) {
+                                remove_wait_queue(&video->waitq, &wait);
+                                set_current_state(TASK_RUNNING);
+                                ret = -EINTR;
+                                goto out;
+                        }
+
+                        schedule();
+                        set_current_state(TASK_INTERRUPTIBLE);
+
+                        spin_lock_irqsave(&video->spinlock, flags);
+                }
+
+                spin_unlock_irqrestore(&video->spinlock, flags);
+
+                remove_wait_queue(&video->waitq, &wait);
+                set_current_state(TASK_RUNNING);
+                ret = 0;
+                break;
+        }
+
+        case DV1394_IOC_RECEIVE_FRAMES: {
+                unsigned int n_recv;
+
+                if ( !video_card_initialized(video) ) {
+                        ret = -EINVAL;
+                        goto out;
+                }
+
+                n_recv = (unsigned int) arg;
+
+                /* at least one frame must be active */
+                if (n_recv > (video->n_frames-1) ) {
+                        ret = -EINVAL;
+                        goto out;
+                }
+
+                spin_lock_irqsave(&video->spinlock, flags);
+
+                /* release the clear frames */
+                video->n_clear_frames -= n_recv;
+
+                /* advance the clear frame cursor */
+                video->first_clear_frame = (video->first_clear_frame + n_recv) % video->n_frames;
+
+                /* reset dropped_frames */
+                video->dropped_frames = 0;
+
+                spin_unlock_irqrestore(&video->spinlock, flags);
+
+                ret = 0;
+                break;
+        }
+
+        case DV1394_IOC_START_RECEIVE: {
+                if ( !video_card_initialized(video) ) {
+                        ret = do_dv1394_init_default(video);
+                        if (ret)
+                                goto out;
+                }
+
+                video->continuity_counter = -1;
+
+                receive_packets(video);
+
+                start_dma_receive(video);
+
+                ret = 0;
+                break;
+        }
+
+        case DV1394_IOC_INIT: {
+                struct dv1394_init init;
+                if (!argp) {
+                        ret = do_dv1394_init_default(video);
+                } else {
+                        if (copy_from_user(&init, argp, sizeof(init))) {
+                                ret = -EFAULT;
+                                goto out;
+                        }
+                        ret = do_dv1394_init(video, &init);
+                }
+                break;
+        }
+
+        case DV1394_IOC_SHUTDOWN:
+                do_dv1394_shutdown(video, 0);
+                ret = 0;
+                break;
+
+
+        case DV1394_IOC_GET_STATUS: {
+                struct dv1394_status status;
+
+                if ( !video_card_initialized(video) ) {
+                        ret = -EINVAL;
+                        goto out;
+                }
+
+                status.init.api_version = DV1394_API_VERSION;
+                status.init.channel = video->channel;
+                status.init.n_frames = video->n_frames;
+                status.init.format = video->pal_or_ntsc;
+                status.init.cip_n = video->cip_n;
+                status.init.cip_d = video->cip_d;
+                status.init.syt_offset = video->syt_offset;
+
+                status.first_clear_frame = video->first_clear_frame;
+
+                /* the rest of the fields need to be locked against the interrupt */
+                spin_lock_irqsave(&video->spinlock, flags);
+
+                status.active_frame = video->active_frame;
+                status.n_clear_frames = video->n_clear_frames;
+
+                status.dropped_frames = video->dropped_frames;
+
+                /* reset dropped_frames */
+                video->dropped_frames = 0;
+
+                spin_unlock_irqrestore(&video->spinlock, flags);
+
+                if (copy_to_user(argp, &status, sizeof(status))) {
+                        ret = -EFAULT;
+                        goto out;
+                }
+
+                ret = 0;
+                break;
+        }
+
+        default:
+                break;
+        }
+
+ out:
+        up(&video->sem);
+        unlock_kernel();
+        return ret;
+}
+
+/*** DEVICE FILE INTERFACE CONTINUED ***************************************/
+
+static int dv1394_open(struct inode *inode, struct file *file)
+{
+        struct video_card *video = NULL;
+
+        /* if the device was opened through devfs, then file->private_data
+           has already been set to video by devfs */
+        if (file->private_data) {
+                video = (struct video_card*) file->private_data;
+
+        } else {
+                /* look up the card by ID */
+                unsigned long flags;
+
+                spin_lock_irqsave(&dv1394_cards_lock, flags);
+                if (!list_empty(&dv1394_cards)) {
+                        struct video_card *p;
+                        list_for_each_entry(p, &dv1394_cards, list) {
+                                if ((p->id) == ieee1394_file_to_instance(file)) {
+                                        video = p;
+                                        break;
+                                }
+                        }
+                }
+                spin_unlock_irqrestore(&dv1394_cards_lock, flags);
+
+                if (!video) {
+                        debug_printk("dv1394: OHCI card %d not found", ieee1394_file_to_instance(file));
+                        return -ENODEV;
+                }
+
+                file->private_data = (void*) video;
+        }
+
+#ifndef DV1394_ALLOW_MORE_THAN_ONE_OPEN
+
+        if ( test_and_set_bit(0, &video->open) ) {
+                /* video is already open by someone else */
+                return -EBUSY;
+        }
+
+#endif
+
+        return 0;
+}
+
+
+static int dv1394_release(struct inode *inode, struct file *file)
+{
+        struct video_card *video = file_to_video_card(file);
+
+        /* OK to free the DMA buffer, no more mappings can exist */
+        do_dv1394_shutdown(video, 1);
+
+        /* clean up async I/O users */
+        dv1394_fasync(-1, file, 0);
+
+        /* give someone else a turn */
+        clear_bit(0, &video->open);
+
+        return 0;
+}
+
+
+/*** DEVICE DRIVER HANDLERS ************************************************/
+
+static void it_tasklet_func(unsigned long data)
+{
+        int wake = 0;
+        struct video_card *video = (struct video_card*) data;
+
+        spin_lock(&video->spinlock);
+
+        if (!video->dma_running)
+                goto out;
+
+        irq_printk("ContextControl = %08x, CommandPtr = %08x\n",
+               reg_read(video->ohci, video->ohci_IsoXmitContextControlSet),
+               reg_read(video->ohci, video->ohci_IsoXmitCommandPtr)
+               );
+
+
+        if ( (video->ohci_it_ctx != -1) &&
+            (reg_read(video->ohci, video->ohci_IsoXmitContextControlSet) & (1 << 10)) ) {
+
+                struct frame *f;
+                unsigned int frame, i;
+
+
+                if (video->active_frame == -1)
+                        frame = 0;
+                else
+                        frame = video->active_frame;
+
+                /* check all the DMA-able frames */
+                for (i = 0; i < video->n_frames; i++, frame = (frame+1) % video->n_frames) {
+
+                        irq_printk("IRQ checking frame %d...", frame);
+                        f = video->frames[frame];
+                        if (f->state != FRAME_READY) {
+                                irq_printk("clear, skipping\n");
+                                /* we don't own this frame */
+                                continue;
+                        }
+
+                        irq_printk("DMA\n");
+
+                        /* check the frame begin semaphore to see if we can free the previous frame */
+                        if ( *(f->frame_begin_timestamp) ) {
+                                int prev_frame;
+                                struct frame *prev_f;
+
+
+
+                                /* don't reset, need this later *(f->frame_begin_timestamp) = 0; */
+                                irq_printk("  BEGIN\n");
+
+                                prev_frame = frame - 1;
+                                if (prev_frame == -1)
+                                        prev_frame += video->n_frames;
+                                prev_f = video->frames[prev_frame];
+
+                                /* make sure we can actually garbage collect
+                                   this frame */
+                                if ( (prev_f->state == FRAME_READY) &&
+                                    prev_f->done && (!f->done) )
+                                {
+                                        frame_reset(prev_f);
+                                        video->n_clear_frames++;
+                                        wake = 1;
+                                        video->active_frame = frame;
+
+                                        irq_printk("  BEGIN - freeing previous frame %d, new active frame is %d\n", prev_frame, frame);
+                                } else {
+                                        irq_printk("  BEGIN - can't free yet\n");
+                                }
+
+                                f->done = 1;
+                        }
+
+
+                        /* see if we need to set the timestamp for the next frame */
+                        if ( *(f->mid_frame_timestamp) ) {
+                                struct frame *next_frame;
+                                u32 begin_ts, ts_cyc, ts_off;
+
+                                *(f->mid_frame_timestamp) = 0;
+
+                                begin_ts = le32_to_cpu(*(f->frame_begin_timestamp));
+
+                                irq_printk("  MIDDLE - first packet was sent at cycle %4u (%2u), assigned timestamp was (%2u) %4u\n",
+                                           begin_ts & 0x1FFF, begin_ts & 0xF,
+                                           f->assigned_timestamp >> 12, f->assigned_timestamp & 0xFFF);
+
+                                /* prepare next frame and assign timestamp */
+                                next_frame = video->frames[ (frame+1) % video->n_frames ];
+
+                                if (next_frame->state == FRAME_READY) {
+                                        irq_printk("  MIDDLE - next frame is ready, good\n");
+                                } else {
+                                        debug_printk("dv1394: Underflow! At least one frame has been dropped.\n");
+                                        next_frame = f;
+                                }
+
+                                /* set the timestamp to the timestamp of the last frame sent,
+                                   plus the length of the last frame sent, plus the syt latency */
+                                ts_cyc = begin_ts & 0xF;
+                                /* advance one frame, plus syt latency (typically 2-3) */
+                                ts_cyc += f->n_packets + video->syt_offset ;
+
+                                ts_off = 0;
+
+                                ts_cyc += ts_off/3072;
+                                ts_off %= 3072;
+
+                                next_frame->assigned_timestamp = ((ts_cyc&0xF) << 12) + ts_off;
+                                if (next_frame->cip_syt1) {
+                                        next_frame->cip_syt1->b[6] = next_frame->assigned_timestamp >> 8;
+                                        next_frame->cip_syt1->b[7] = next_frame->assigned_timestamp & 0xFF;
+                                }
+                                if (next_frame->cip_syt2) {
+                                        next_frame->cip_syt2->b[6] = next_frame->assigned_timestamp >> 8;
+                                        next_frame->cip_syt2->b[7] = next_frame->assigned_timestamp & 0xFF;
+                                }
+
+                        }
+
+                        /* see if the frame looped */
+                        if ( *(f->frame_end_timestamp) ) {
+
+                                *(f->frame_end_timestamp) = 0;
+
+                                debug_printk("  END - the frame looped at least once\n");
+
+                                video->dropped_frames++;
+                        }
+
+                } /* for (each frame) */
+        }
+
+        if (wake) {
+                kill_fasync(&video->fasync, SIGIO, POLL_OUT);
+
+                /* wake readers/writers/ioctl'ers */
+                wake_up_interruptible(&video->waitq);
+        }
+
+out:
+        spin_unlock(&video->spinlock);
+}
+
+static void ir_tasklet_func(unsigned long data)
+{
+        int wake = 0;
+        struct video_card *video = (struct video_card*) data;
+
+        spin_lock(&video->spinlock);
+
+        if (!video->dma_running)
+                goto out;
+
+        if ( (video->ohci_ir_ctx != -1) &&
+            (reg_read(video->ohci, video->ohci_IsoRcvContextControlSet) & (1 << 10)) ) {
+
+                int sof=0; /* start-of-frame flag */
+                struct frame *f;
+                u16 packet_length, packet_time;
+                int i, dbc=0;
+                struct DMA_descriptor_block *block = NULL;
+                u16 xferstatus;
+
+                int next_i, prev_i;
+                struct DMA_descriptor_block *next = NULL;
+                dma_addr_t next_dma = 0;
+                struct DMA_descriptor_block *prev = NULL;
+
+                /* loop over all descriptors in all frames */
+                for (i = 0; i < video->n_frames*MAX_PACKETS; i++) {
+                        struct packet *p = dma_region_i(&video->packet_buf, struct packet, video->current_packet);
+
+                        /* make sure we are seeing the latest changes to p */
+                        dma_region_sync_for_cpu(&video->packet_buf,
+                                                (unsigned long) p - (unsigned long) video->packet_buf.kvirt,
+                                                sizeof(struct packet));
+
+                        packet_length = le16_to_cpu(p->data_length);
+                        packet_time   = le16_to_cpu(p->timestamp);
+
+                        irq_printk("received packet %02d, timestamp=%04x, length=%04x, sof=%02x%02x\n", video->current_packet,
+                                   packet_time, packet_length,
+                                   p->data[0], p->data[1]);
+
+                        /* get the descriptor based on packet_buffer cursor */
+                        f = video->frames[video->current_packet / MAX_PACKETS];
+                        block = &(f->descriptor_pool[video->current_packet % MAX_PACKETS]);
+                        xferstatus = le32_to_cpu(block->u.in.il.q[3]) >> 16;
+                        xferstatus &= 0x1F;
+                        irq_printk("ir_tasklet_func: xferStatus/resCount [%d] = 0x%08x\n", i, le32_to_cpu(block->u.in.il.q[3]) );
+
+                        /* get the current frame */
+                        f = video->frames[video->active_frame];
+
+                        /* exclude empty packet */
+                        if (packet_length > 8 && xferstatus == 0x11) {
+                                /* check for start of frame */
+                                /* DRD> Changed to check section type ([0]>>5==0)
+                                   and dif sequence ([1]>>4==0) */
+                                sof = ( (p->data[0] >> 5) == 0 && (p->data[1] >> 4) == 0);
+
+                                dbc = (int) (p->cip_h1 >> 24);
+                                if ( video->continuity_counter != -1 && dbc > ((video->continuity_counter + 1) % 256) )
+                                {
+                                        printk(KERN_WARNING "dv1394: discontinuity detected, dropping all frames\n" );
+                                        video->dropped_frames += video->n_clear_frames + 1;
+                                        video->first_frame = 0;
+                                        video->n_clear_frames = 0;
+                                        video->first_clear_frame = -1;
+                                }
+                                video->continuity_counter = dbc;
+
+                                if (!video->first_frame) {
+                                        if (sof) {
+                                                video->first_frame = 1;
+                                        }
+
+                                } else if (sof) {
+                                        /* close current frame */
+                                        frame_reset(f);  /* f->state = STATE_CLEAR */
+                                        video->n_clear_frames++;
+                                        if (video->n_clear_frames > video->n_frames) {
+                                                video->dropped_frames++;
+                                                printk(KERN_WARNING "dv1394: dropped a frame during reception\n" );
+                                                video->n_clear_frames = video->n_frames-1;
+                                                video->first_clear_frame = (video->first_clear_frame + 1) % video->n_frames;
+                                        }
+                                        if (video->first_clear_frame == -1)
+                                                video->first_clear_frame = video->active_frame;
+
+                                        /* get the next frame */
+                                        video->active_frame = (video->active_frame + 1) % video->n_frames;
+                                        f = video->frames[video->active_frame];
+                                        irq_printk("   frame received, active_frame = %d, n_clear_frames = %d, first_clear_frame = %d\n",
+                                                   video->active_frame, video->n_clear_frames, video->first_clear_frame);
+                                }
+                                if (video->first_frame) {
+                                        if (sof) {
+                                                /* open next frame */
+                                                f->state = FRAME_READY;
+                                        }
+
+                                        /* copy to buffer */
+                                        if (f->n_packets > (video->frame_size / 480)) {
+                                                printk(KERN_ERR "frame buffer overflow during receive\n");
+                                        }
+
+                                        frame_put_packet(f, p);
+
+                                } /* first_frame */
+                        }
+
+                        /* stop, end of ready packets */
+                        else if (xferstatus == 0) {
+                                break;
+                        }
+
+                        /* reset xferStatus & resCount */
+                        block->u.in.il.q[3] = cpu_to_le32(512);
+
+                        /* terminate dma chain at this (next) packet */
+                        next_i = video->current_packet;
+                        f = video->frames[next_i / MAX_PACKETS];
+                        next = &(f->descriptor_pool[next_i % MAX_PACKETS]);
+                        next_dma = ((unsigned long) block - (unsigned long) f->descriptor_pool) + f->descriptor_pool_dma;
+                        next->u.in.il.q[0] |= 3 << 20; /* enable interrupt */
+                        next->u.in.il.q[2] = 0; /* disable branch */
+
+                        /* link previous to next */
+                        prev_i = (next_i == 0) ? (MAX_PACKETS * video->n_frames - 1) : (next_i - 1);
+                        f = video->frames[prev_i / MAX_PACKETS];
+                        prev = &(f->descriptor_pool[prev_i % MAX_PACKETS]);
+                        if (prev_i % (MAX_PACKETS/2)) {
+                                prev->u.in.il.q[0] &= ~(3 << 20); /* no interrupt */
+                        } else {
+                                prev->u.in.il.q[0] |= 3 << 20; /* enable interrupt */
+                        }
+                        prev->u.in.il.q[2] = cpu_to_le32(next_dma | 1); /* set Z=1 */
+                        wmb();
+
+                        /* wake up DMA in case it fell asleep */
+                        reg_write(video->ohci, video->ohci_IsoRcvContextControlSet, (1 << 12));
+
+                        /* advance packet_buffer cursor */
+                        video->current_packet = (video->current_packet + 1) % (MAX_PACKETS * video->n_frames);
+
+                } /* for all packets */
+
+                wake = 1; /* why the hell not? */
+
+        } /* receive interrupt */
+
+        if (wake) {
+                kill_fasync(&video->fasync, SIGIO, POLL_IN);
+
+                /* wake readers/writers/ioctl'ers */
+                wake_up_interruptible(&video->waitq);
+        }
+
+out:
+        spin_unlock(&video->spinlock);
+}
+
+static struct cdev dv1394_cdev;
+static struct file_operations dv1394_fops=
+{
+        .owner =        THIS_MODULE,
+        .poll =         dv1394_poll,
+        .unlocked_ioctl = dv1394_ioctl,
+#ifdef CONFIG_COMPAT
+        .compat_ioctl = dv1394_compat_ioctl,
+#endif
+        .mmap =         dv1394_mmap,
+        .open =         dv1394_open,
+        .write =        dv1394_write,
+        .read =         dv1394_read,
+        .release =      dv1394_release,
+        .fasync =       dv1394_fasync,
+};
+
+
+/*** HOTPLUG STUFF **********************************************************/
+/*
+ * Export information about protocols/devices supported by this driver.
+ */
+static struct ieee1394_device_id dv1394_id_table[] = {
+        {
+                .match_flags    = IEEE1394_MATCH_SPECIFIER_ID | IEEE1394_MATCH_VERSION,
+                .specifier_id   = AVC_UNIT_SPEC_ID_ENTRY & 0xffffff,
+                .version        = AVC_SW_VERSION_ENTRY & 0xffffff
+        },
+        { }
+};
+
+MODULE_DEVICE_TABLE(ieee1394, dv1394_id_table);
+
+static struct hpsb_protocol_driver dv1394_driver = {
+        .name           = "DV/1394 Driver",
+        .id_table       = dv1394_id_table,
+        .driver         = {
+                .name   = "dv1394",
+                .bus    = &ieee1394_bus_type,
+        },
+};
+
+
+/*** IEEE1394 HPSB CALLBACKS ***********************************************/
+
+static int dv1394_init(struct ti_ohci *ohci, enum pal_or_ntsc format, enum modes mode)
+{
+        struct video_card *video;
+        unsigned long flags;
+        int i;
+
+        video = kmalloc(sizeof(struct video_card), GFP_KERNEL);
+        if (!video) {
+                printk(KERN_ERR "dv1394: cannot allocate video_card\n");
+                goto err;
+        }
+
+        memset(video, 0, sizeof(struct video_card));
+
+        video->ohci = ohci;
+        /* lower 2 bits of id indicate which of four "plugs"
+           per host */
+        video->id = ohci->host->id << 2;
+        if (format == DV1394_NTSC)
+                video->id |= mode;
+        else
+                video->id |= 2 + mode;
+
+        video->ohci_it_ctx = -1;
+        video->ohci_ir_ctx = -1;
+
+        video->ohci_IsoXmitContextControlSet = 0;
+        video->ohci_IsoXmitContextControlClear = 0;
+        video->ohci_IsoXmitCommandPtr = 0;
+
+        video->ohci_IsoRcvContextControlSet = 0;
+        video->ohci_IsoRcvContextControlClear = 0;
+        video->ohci_IsoRcvCommandPtr = 0;
+        video->ohci_IsoRcvContextMatch = 0;
+
+        video->n_frames = 0; /* flag that video is not initialized */
+        video->channel = 63; /* default to broadcast channel */
+        video->active_frame = -1;
+
+        /* initialize the following */
+        video->pal_or_ntsc = format;
+        video->cip_n = 0; /* 0 = use builtin default */
+        video->cip_d = 0;
+        video->syt_offset = 0;
+        video->mode = mode;
+
+        for (i = 0; i < DV1394_MAX_FRAMES; i++)
+                video->frames[i] = NULL;
+
+        dma_region_init(&video->dv_buf);
+        video->dv_buf_size = 0;
+        dma_region_init(&video->packet_buf);
+        video->packet_buf_size = 0;
+
+        clear_bit(0, &video->open);
+        spin_lock_init(&video->spinlock);
+        video->dma_running = 0;
+        init_MUTEX(&video->sem);
+        init_waitqueue_head(&video->waitq);
+        video->fasync = NULL;
+
+        spin_lock_irqsave(&dv1394_cards_lock, flags);
+        INIT_LIST_HEAD(&video->list);
+        list_add_tail(&video->list, &dv1394_cards);
+        spin_unlock_irqrestore(&dv1394_cards_lock, flags);
+
+        if (devfs_mk_cdev(MKDEV(IEEE1394_MAJOR,
+                                IEEE1394_MINOR_BLOCK_DV1394*16 + video->id),
+                        S_IFCHR|S_IRUGO|S_IWUGO,
+                         "ieee1394/dv/host%d/%s/%s",
+                         (video->id>>2),
+                         (video->pal_or_ntsc == DV1394_NTSC ? "NTSC" : "PAL"),
+                         (video->mode == MODE_RECEIVE ? "in" : "out")) < 0)
+                        goto err_free;
+
+        debug_printk("dv1394: dv1394_init() OK on ID %d\n", video->id);
+
+        return 0;
+
+ err_free:
+        kfree(video);
+ err:
+        return -1;
+}
+
+static void dv1394_un_init(struct video_card *video)
+{
+        char buf[32];
+
+        /* obviously nobody has the driver open at this point */
+        do_dv1394_shutdown(video, 1);
+        snprintf(buf, sizeof(buf), "dv/host%d/%s/%s", (video->id >> 2),
+                (video->pal_or_ntsc == DV1394_NTSC ? "NTSC" : "PAL"),
+                (video->mode == MODE_RECEIVE ? "in" : "out")
+                );
+
+        devfs_remove("ieee1394/%s", buf);
+        kfree(video);
+}
+
+
+static void dv1394_remove_host (struct hpsb_host *host)
+{
+        struct video_card *video;
+        unsigned long flags;
+        int id = host->id;
+
+        /* We only work with the OHCI-1394 driver */
+        if (strcmp(host->driver->name, OHCI1394_DRIVER_NAME))
+                return;
+
+        /* find the corresponding video_cards */
+        do {
+                struct video_card *tmp_vid;
+
+                video = NULL;
+
+                spin_lock_irqsave(&dv1394_cards_lock, flags);
+                list_for_each_entry(tmp_vid, &dv1394_cards, list) {
+                        if ((tmp_vid->id >> 2) == id) {
+                                list_del(&tmp_vid->list);
+                                video = tmp_vid;
+                                break;
+                        }
+                }
+                spin_unlock_irqrestore(&dv1394_cards_lock, flags);
+
+                if (video)
+                        dv1394_un_init(video);
+        } while (video != NULL);
+
+        class_simple_device_remove(MKDEV(
+                IEEE1394_MAJOR, IEEE1394_MINOR_BLOCK_DV1394 * 16 + (id<<2)));
+        devfs_remove("ieee1394/dv/host%d/NTSC", id);
+        devfs_remove("ieee1394/dv/host%d/PAL", id);
+        devfs_remove("ieee1394/dv/host%d", id);
+}
+
+static void dv1394_add_host (struct hpsb_host *host)
+{
+        struct ti_ohci *ohci;
+        int id = host->id;
+
+        /* We only work with the OHCI-1394 driver */
+        if (strcmp(host->driver->name, OHCI1394_DRIVER_NAME))
+                return;
+
+        ohci = (struct ti_ohci *)host->hostdata;
+
+        class_simple_device_add(hpsb_protocol_class, MKDEV(
+                IEEE1394_MAJOR, IEEE1394_MINOR_BLOCK_DV1394 * 16 + (id<<2)), 
+                NULL, "dv1394-%d", id);
+        devfs_mk_dir("ieee1394/dv/host%d", id);
+        devfs_mk_dir("ieee1394/dv/host%d/NTSC", id);
+        devfs_mk_dir("ieee1394/dv/host%d/PAL", id);
+
+        dv1394_init(ohci, DV1394_NTSC, MODE_RECEIVE);
+        dv1394_init(ohci, DV1394_NTSC, MODE_TRANSMIT);
+        dv1394_init(ohci, DV1394_PAL, MODE_RECEIVE);
+        dv1394_init(ohci, DV1394_PAL, MODE_TRANSMIT);
+}
+
+
+/* Bus reset handler. In the event of a bus reset, we may need to
+   re-start the DMA contexts - otherwise the user program would
+   end up waiting forever.
+*/
+
+static void dv1394_host_reset(struct hpsb_host *host)
+{
+        struct ti_ohci *ohci;
+        struct video_card *video = NULL, *tmp_vid;
+        unsigned long flags;
+
+        /* We only work with the OHCI-1394 driver */
+        if (strcmp(host->driver->name, OHCI1394_DRIVER_NAME))
+                return;
+
+        ohci = (struct ti_ohci *)host->hostdata;
+
+
+        /* find the corresponding video_cards */
+        spin_lock_irqsave(&dv1394_cards_lock, flags);
+        list_for_each_entry(tmp_vid, &dv1394_cards, list) {
+                if ((tmp_vid->id >> 2) == host->id) {
+                        video = tmp_vid;
+                        break;
+                }
+        }
+        spin_unlock_irqrestore(&dv1394_cards_lock, flags);
+
+        if (!video)
+                return;
+
+
+        spin_lock_irqsave(&video->spinlock, flags);
+
+        if (!video->dma_running)
+                goto out;
+
+        /* check IT context */
+        if (video->ohci_it_ctx != -1) {
+                u32 ctx;
+
+                ctx = reg_read(video->ohci, video->ohci_IsoXmitContextControlSet);
+
+                /* if (RUN but not ACTIVE) */
+                if ( (ctx & (1<<15)) &&
+                    !(ctx & (1<<10)) ) {
+
+                        debug_printk("dv1394: IT context stopped due to bus reset; waking it up\n");
+
+                        /* to be safe, assume a frame has been dropped. User-space programs
+                           should handle this condition like an underflow. */
+                        video->dropped_frames++;
+
+                        /* for some reason you must clear, then re-set the RUN bit to restart DMA */
+
+                        /* clear RUN */
+                        reg_write(video->ohci, video->ohci_IsoXmitContextControlClear, (1 << 15));
+                        flush_pci_write(video->ohci);
+
+                        /* set RUN */
+                        reg_write(video->ohci, video->ohci_IsoXmitContextControlSet, (1 << 15));
+                        flush_pci_write(video->ohci);
+
+                        /* set the WAKE bit (just in case; this isn't strictly necessary) */
+                        reg_write(video->ohci, video->ohci_IsoXmitContextControlSet, (1 << 12));
+                        flush_pci_write(video->ohci);
+
+                        irq_printk("dv1394: AFTER IT restart ctx 0x%08x ptr 0x%08x\n",
+                                   reg_read(video->ohci, video->ohci_IsoXmitContextControlSet),
+                                   reg_read(video->ohci, video->ohci_IsoXmitCommandPtr));
+                }
+        }
+
+        /* check IR context */
+        if (video->ohci_ir_ctx != -1) {
+                u32 ctx;
+
+                ctx = reg_read(video->ohci, video->ohci_IsoRcvContextControlSet);
+
+                /* if (RUN but not ACTIVE) */
+                if ( (ctx & (1<<15)) &&
+                    !(ctx & (1<<10)) ) {
+
+                        debug_printk("dv1394: IR context stopped due to bus reset; waking it up\n");
+
+                        /* to be safe, assume a frame has been dropped. User-space programs
+                           should handle this condition like an overflow. */
+                        video->dropped_frames++;
+
+                        /* for some reason you must clear, then re-set the RUN bit to restart DMA */
+                        /* XXX this doesn't work for me, I can't get IR DMA to restart :[ */
+
+                        /* clear RUN */
+                        reg_write(video->ohci, video->ohci_IsoRcvContextControlClear, (1 << 15));
+                        flush_pci_write(video->ohci);
+
+                        /* set RUN */
+                        reg_write(video->ohci, video->ohci_IsoRcvContextControlSet, (1 << 15));
+                        flush_pci_write(video->ohci);
+
+                        /* set the WAKE bit (just in case; this isn't strictly necessary) */
+                        reg_write(video->ohci, video->ohci_IsoRcvContextControlSet, (1 << 12));
+                        flush_pci_write(video->ohci);
+
+                        irq_printk("dv1394: AFTER IR restart ctx 0x%08x ptr 0x%08x\n",
+                                   reg_read(video->ohci, video->ohci_IsoRcvContextControlSet),
+                                   reg_read(video->ohci, video->ohci_IsoRcvCommandPtr));
+                }
+        }
+
+out:
+        spin_unlock_irqrestore(&video->spinlock, flags);
+
+        /* wake readers/writers/ioctl'ers */
+        wake_up_interruptible(&video->waitq);
+}
+
+static struct hpsb_highlevel dv1394_highlevel = {
+        .name =         "dv1394",
+        .add_host =     dv1394_add_host,
+        .remove_host =  dv1394_remove_host,
+        .host_reset =   dv1394_host_reset,
+};
+
+#ifdef CONFIG_COMPAT
+
+#define DV1394_IOC32_INIT       _IOW('#', 0x06, struct dv1394_init32)
+#define DV1394_IOC32_GET_STATUS _IOR('#', 0x0c, struct dv1394_status32)
+
+struct dv1394_init32 {
+        u32 api_version;
+        u32 channel;
+        u32 n_frames;
+        u32 format;
+        u32 cip_n;
+        u32 cip_d;
+        u32 syt_offset;
+};
+
+struct dv1394_status32 {
+        struct dv1394_init32 init;
+        s32 active_frame;
+        u32 first_clear_frame;
+        u32 n_clear_frames;
+        u32 dropped_frames;
+};
+
+/* RED-PEN: this should use compat_alloc_userspace instead */
+
+static int handle_dv1394_init(struct file *file, unsigned int cmd, unsigned long arg)
+{
+        struct dv1394_init32 dv32;
+        struct dv1394_init dv;
+        mm_segment_t old_fs;
+        int ret;
+
+        if (file->f_op->unlocked_ioctl != dv1394_ioctl)
+                return -EFAULT;
+
+        if (copy_from_user(&dv32, (void __user *)arg, sizeof(dv32)))
+                return -EFAULT;
+
+        dv.api_version = dv32.api_version;
+        dv.channel = dv32.channel;
+        dv.n_frames = dv32.n_frames;
+        dv.format = dv32.format;
+        dv.cip_n = (unsigned long)dv32.cip_n;
+        dv.cip_d = (unsigned long)dv32.cip_d;
+        dv.syt_offset = dv32.syt_offset;
+
+        old_fs = get_fs();
+        set_fs(KERNEL_DS);
+        ret = dv1394_ioctl(file, DV1394_IOC_INIT, (unsigned long)&dv);
+        set_fs(old_fs);
+
+        return ret;
+}
+
+static int handle_dv1394_get_status(struct file *file, unsigned int cmd, unsigned long arg)
+{
+        struct dv1394_status32 dv32;
+        struct dv1394_status dv;
+        mm_segment_t old_fs;
+        int ret;
+
+        if (file->f_op->unlocked_ioctl != dv1394_ioctl)
+                return -EFAULT;
+
+        old_fs = get_fs();
+        set_fs(KERNEL_DS);
+        ret = dv1394_ioctl(file, DV1394_IOC_GET_STATUS, (unsigned long)&dv);
+        set_fs(old_fs);
+
+        if (!ret) {
+                dv32.init.api_version = dv.init.api_version;
+                dv32.init.channel = dv.init.channel;
+                dv32.init.n_frames = dv.init.n_frames;
+                dv32.init.format = dv.init.format;
+                dv32.init.cip_n = (u32)dv.init.cip_n;
+                dv32.init.cip_d = (u32)dv.init.cip_d;
+                dv32.init.syt_offset = dv.init.syt_offset;
+                dv32.active_frame = dv.active_frame;
+                dv32.first_clear_frame = dv.first_clear_frame;
+                dv32.n_clear_frames = dv.n_clear_frames;
+                dv32.dropped_frames = dv.dropped_frames;
+
+                if (copy_to_user((struct dv1394_status32 __user *)arg, &dv32, sizeof(dv32)))
+                        ret = -EFAULT;
+        }
+
+        return ret;
+}
+
+
+
+static long dv1394_compat_ioctl(struct file *file, unsigned int cmd,
+                               unsigned long arg)
+{
+        switch (cmd) {
+        case DV1394_IOC_SHUTDOWN:
+        case DV1394_IOC_SUBMIT_FRAMES:
+        case DV1394_IOC_WAIT_FRAMES:
+        case DV1394_IOC_RECEIVE_FRAMES:
+        case DV1394_IOC_START_RECEIVE:
+                return dv1394_ioctl(file, cmd, arg);
+
+        case DV1394_IOC32_INIT:
+                return handle_dv1394_init(file, cmd, arg);
+        case DV1394_IOC32_GET_STATUS:
+                return handle_dv1394_get_status(file, cmd, arg);
+        default:
+                return -ENOIOCTLCMD;
+        }
+}
+
+#endif /* CONFIG_COMPAT */
+
+
+/*** KERNEL MODULE HANDLERS ************************************************/
+
+MODULE_AUTHOR("Dan Maas <dmaas@dcine.com>, Dan Dennedy <dan@dennedy.org>");
+MODULE_DESCRIPTION("driver for DV input/output on OHCI board");
+MODULE_SUPPORTED_DEVICE("dv1394");
+MODULE_LICENSE("GPL");
+
+static void __exit dv1394_exit_module(void)
+{
+        hpsb_unregister_protocol(&dv1394_driver);
+
+        hpsb_unregister_highlevel(&dv1394_highlevel);
+        cdev_del(&dv1394_cdev);
+        devfs_remove("ieee1394/dv");
+}
+
+static int __init dv1394_init_module(void)
+{
+        int ret;
+
+        cdev_init(&dv1394_cdev, &dv1394_fops);
+        dv1394_cdev.owner = THIS_MODULE;
+        kobject_set_name(&dv1394_cdev.kobj, "dv1394");
+        ret = cdev_add(&dv1394_cdev, IEEE1394_DV1394_DEV, 16);
+        if (ret) {
+                printk(KERN_ERR "dv1394: unable to register character device\n");
+                return ret;
+        }
+
+        devfs_mk_dir("ieee1394/dv");
+
+        hpsb_register_highlevel(&dv1394_highlevel);
+
+        ret = hpsb_register_protocol(&dv1394_driver);
+        if (ret) {
+                printk(KERN_ERR "dv1394: failed to register protocol\n");
+                hpsb_unregister_highlevel(&dv1394_highlevel);
+                devfs_remove("ieee1394/dv");
+                cdev_del(&dv1394_cdev);
+                return ret;
+        }
+
+        return 0;
+}
+
+module_init(dv1394_init_module);
+module_exit(dv1394_exit_module);
+MODULE_ALIAS_CHARDEV(IEEE1394_MAJOR, IEEE1394_MINOR_BLOCK_DV1394 * 16);