Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6

Conflicts:
	arch/microblaze/include/asm/socket.h

1 files changed, 1213 insertions, 0 deletions

diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
new file mode 100644
index 000000000000..9a1e5fb412ed
--- /dev/null
+++ b/drivers/dma/at_hdmac.c
@@ -0,0 +1,1213 @@
+/*
+ * Driver for the Atmel AHB DMA Controller (aka HDMA or DMAC on AT91 systems)
+ *
+ * Copyright (C) 2008 Atmel Corporation
+ *
+ * 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 supports the Atmel AHB DMA Controller,
+ *
+ * The driver has currently been tested with the Atmel AT91SAM9RL
+ * and AT91SAM9G45 series.
+ */
+
+#include <linux/clk.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmapool.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#include "at_hdmac_regs.h"
+
+/*
+ * Glossary
+ * --------
+ *
+ * at_hdmac             : Name of the ATmel AHB DMA Controller
+ * at_dma_ / atdma      : ATmel DMA controller entity related
+ * atc_ / atchan        : ATmel DMA Channel entity related
+ */
+
+#define ATC_DEFAULT_CFG         (ATC_FIFOCFG_HALFFIFO)
+#define ATC_DEFAULT_CTRLA       (0)
+#define ATC_DEFAULT_CTRLB       (ATC_SIF(0)     \
+                                |ATC_DIF(1))
+
+/*
+ * Initial number of descriptors to allocate for each channel. This could
+ * be increased during dma usage.
+ */
+static unsigned int init_nr_desc_per_channel = 64;
+module_param(init_nr_desc_per_channel, uint, 0644);
+MODULE_PARM_DESC(init_nr_desc_per_channel,
+                 "initial descriptors per channel (default: 64)");
+
+
+/* prototypes */
+static dma_cookie_t atc_tx_submit(struct dma_async_tx_descriptor *tx);
+
+
+/*----------------------------------------------------------------------*/
+
+static struct at_desc *atc_first_active(struct at_dma_chan *atchan)
+{
+        return list_first_entry(&atchan->active_list,
+                                struct at_desc, desc_node);
+}
+
+static struct at_desc *atc_first_queued(struct at_dma_chan *atchan)
+{
+        return list_first_entry(&atchan->queue,
+                                struct at_desc, desc_node);
+}
+
+/**
+ * atc_alloc_descriptor - allocate and return an initilized descriptor
+ * @chan: the channel to allocate descriptors for
+ * @gfp_flags: GFP allocation flags
+ *
+ * Note: The ack-bit is positioned in the descriptor flag at creation time
+ *       to make initial allocation more convenient. This bit will be cleared
+ *       and control will be given to client at usage time (during
+ *       preparation functions).
+ */
+static struct at_desc *atc_alloc_descriptor(struct dma_chan *chan,
+                                            gfp_t gfp_flags)
+{
+        struct at_desc  *desc = NULL;
+        struct at_dma   *atdma = to_at_dma(chan->device);
+        dma_addr_t phys;
+
+        desc = dma_pool_alloc(atdma->dma_desc_pool, gfp_flags, &phys);
+        if (desc) {
+                memset(desc, 0, sizeof(struct at_desc));
+                dma_async_tx_descriptor_init(&desc->txd, chan);
+                /* txd.flags will be overwritten in prep functions */
+                desc->txd.flags = DMA_CTRL_ACK;
+                desc->txd.tx_submit = atc_tx_submit;
+                desc->txd.phys = phys;
+        }
+
+        return desc;
+}
+
+/**
+ * atc_desc_get - get a unsused descriptor from free_list
+ * @atchan: channel we want a new descriptor for
+ */
+static struct at_desc *atc_desc_get(struct at_dma_chan *atchan)
+{
+        struct at_desc *desc, *_desc;
+        struct at_desc *ret = NULL;
+        unsigned int i = 0;
+        LIST_HEAD(tmp_list);
+
+        spin_lock_bh(&atchan->lock);
+        list_for_each_entry_safe(desc, _desc, &atchan->free_list, desc_node) {
+                i++;
+                if (async_tx_test_ack(&desc->txd)) {
+                        list_del(&desc->desc_node);
+                        ret = desc;
+                        break;
+                }
+                dev_dbg(chan2dev(&atchan->chan_common),
+                                "desc %p not ACKed\n", desc);
+        }
+        spin_unlock_bh(&atchan->lock);
+        dev_vdbg(chan2dev(&atchan->chan_common),
+                "scanned %u descriptors on freelist\n", i);
+
+        /* no more descriptor available in initial pool: create one more */
+        if (!ret) {
+                ret = atc_alloc_descriptor(&atchan->chan_common, GFP_ATOMIC);
+                if (ret) {
+                        spin_lock_bh(&atchan->lock);
+                        atchan->descs_allocated++;
+                        spin_unlock_bh(&atchan->lock);
+                } else {
+                        dev_err(chan2dev(&atchan->chan_common),
+                                        "not enough descriptors available\n");
+                }
+        }
+
+        return ret;
+}
+
+/**
+ * atc_desc_put - move a descriptor, including any children, to the free list
+ * @atchan: channel we work on
+ * @desc: descriptor, at the head of a chain, to move to free list
+ */
+static void atc_desc_put(struct at_dma_chan *atchan, struct at_desc *desc)
+{
+        if (desc) {
+                struct at_desc *child;
+
+                spin_lock_bh(&atchan->lock);
+                list_for_each_entry(child, &desc->txd.tx_list, desc_node)
+                        dev_vdbg(chan2dev(&atchan->chan_common),
+                                        "moving child desc %p to freelist\n",
+                                        child);
+                list_splice_init(&desc->txd.tx_list, &atchan->free_list);
+                dev_vdbg(chan2dev(&atchan->chan_common),
+                         "moving desc %p to freelist\n", desc);
+                list_add(&desc->desc_node, &atchan->free_list);
+                spin_unlock_bh(&atchan->lock);
+        }
+}
+
+/**
+ * atc_assign_cookie - compute and assign new cookie
+ * @atchan: channel we work on
+ * @desc: descriptor to asign cookie for
+ *
+ * Called with atchan->lock held and bh disabled
+ */
+static dma_cookie_t
+atc_assign_cookie(struct at_dma_chan *atchan, struct at_desc *desc)
+{
+        dma_cookie_t cookie = atchan->chan_common.cookie;
+
+        if (++cookie < 0)
+                cookie = 1;
+
+        atchan->chan_common.cookie = cookie;
+        desc->txd.cookie = cookie;
+
+        return cookie;
+}
+
+/**
+ * atc_dostart - starts the DMA engine for real
+ * @atchan: the channel we want to start
+ * @first: first descriptor in the list we want to begin with
+ *
+ * Called with atchan->lock held and bh disabled
+ */
+static void atc_dostart(struct at_dma_chan *atchan, struct at_desc *first)
+{
+        struct at_dma   *atdma = to_at_dma(atchan->chan_common.device);
+
+        /* ASSERT:  channel is idle */
+        if (atc_chan_is_enabled(atchan)) {
+                dev_err(chan2dev(&atchan->chan_common),
+                        "BUG: Attempted to start non-idle channel\n");
+                dev_err(chan2dev(&atchan->chan_common),
+                        "  channel: s0x%x d0x%x ctrl0x%x:0x%x l0x%x\n",
+                        channel_readl(atchan, SADDR),
+                        channel_readl(atchan, DADDR),
+                        channel_readl(atchan, CTRLA),
+                        channel_readl(atchan, CTRLB),
+                        channel_readl(atchan, DSCR));
+
+                /* The tasklet will hopefully advance the queue... */
+                return;
+        }
+
+        vdbg_dump_regs(atchan);
+
+        /* clear any pending interrupt */
+        while (dma_readl(atdma, EBCISR))
+                cpu_relax();
+
+        channel_writel(atchan, SADDR, 0);
+        channel_writel(atchan, DADDR, 0);
+        channel_writel(atchan, CTRLA, 0);
+        channel_writel(atchan, CTRLB, 0);
+        channel_writel(atchan, DSCR, first->txd.phys);
+        dma_writel(atdma, CHER, atchan->mask);
+
+        vdbg_dump_regs(atchan);
+}
+
+/**
+ * atc_chain_complete - finish work for one transaction chain
+ * @atchan: channel we work on
+ * @desc: descriptor at the head of the chain we want do complete
+ *
+ * Called with atchan->lock held and bh disabled */
+static void
+atc_chain_complete(struct at_dma_chan *atchan, struct at_desc *desc)
+{
+        dma_async_tx_callback           callback;
+        void                            *param;
+        struct dma_async_tx_descriptor  *txd = &desc->txd;
+
+        dev_vdbg(chan2dev(&atchan->chan_common),
+                "descriptor %u complete\n", txd->cookie);
+
+        atchan->completed_cookie = txd->cookie;
+        callback = txd->callback;
+        param = txd->callback_param;
+
+        /* move children to free_list */
+        list_splice_init(&txd->tx_list, &atchan->free_list);
+        /* move myself to free_list */
+        list_move(&desc->desc_node, &atchan->free_list);
+
+        /* unmap dma addresses */
+        if (!(txd->flags & DMA_COMPL_SKIP_DEST_UNMAP)) {
+                if (txd->flags & DMA_COMPL_DEST_UNMAP_SINGLE)
+                        dma_unmap_single(chan2parent(&atchan->chan_common),
+                                        desc->lli.daddr,
+                                        desc->len, DMA_FROM_DEVICE);
+                else
+                        dma_unmap_page(chan2parent(&atchan->chan_common),
+                                        desc->lli.daddr,
+                                        desc->len, DMA_FROM_DEVICE);
+        }
+        if (!(txd->flags & DMA_COMPL_SKIP_SRC_UNMAP)) {
+                if (txd->flags & DMA_COMPL_SRC_UNMAP_SINGLE)
+                        dma_unmap_single(chan2parent(&atchan->chan_common),
+                                        desc->lli.saddr,
+                                        desc->len, DMA_TO_DEVICE);
+                else
+                        dma_unmap_page(chan2parent(&atchan->chan_common),
+                                        desc->lli.saddr,
+                                        desc->len, DMA_TO_DEVICE);
+        }
+
+        /*
+         * The API requires that no submissions are done from a
+         * callback, so we don't need to drop the lock here
+         */
+        if (callback)
+                callback(param);
+
+        dma_run_dependencies(txd);
+}
+
+/**
+ * atc_complete_all - finish work for all transactions
+ * @atchan: channel to complete transactions for
+ *
+ * Eventually submit queued descriptors if any
+ *
+ * Assume channel is idle while calling this function
+ * Called with atchan->lock held and bh disabled
+ */
+static void atc_complete_all(struct at_dma_chan *atchan)
+{
+        struct at_desc *desc, *_desc;
+        LIST_HEAD(list);
+
+        dev_vdbg(chan2dev(&atchan->chan_common), "complete all\n");
+
+        BUG_ON(atc_chan_is_enabled(atchan));
+
+        /*
+         * Submit queued descriptors ASAP, i.e. before we go through
+         * the completed ones.
+         */
+        if (!list_empty(&atchan->queue))
+                atc_dostart(atchan, atc_first_queued(atchan));
+        /* empty active_list now it is completed */
+        list_splice_init(&atchan->active_list, &list);
+        /* empty queue list by moving descriptors (if any) to active_list */
+        list_splice_init(&atchan->queue, &atchan->active_list);
+
+        list_for_each_entry_safe(desc, _desc, &list, desc_node)
+                atc_chain_complete(atchan, desc);
+}
+
+/**
+ * atc_cleanup_descriptors - cleanup up finished descriptors in active_list
+ * @atchan: channel to be cleaned up
+ *
+ * Called with atchan->lock held and bh disabled
+ */
+static void atc_cleanup_descriptors(struct at_dma_chan *atchan)
+{
+        struct at_desc  *desc, *_desc;
+        struct at_desc  *child;
+
+        dev_vdbg(chan2dev(&atchan->chan_common), "cleanup descriptors\n");
+
+        list_for_each_entry_safe(desc, _desc, &atchan->active_list, desc_node) {
+                if (!(desc->lli.ctrla & ATC_DONE))
+                        /* This one is currently in progress */
+                        return;
+
+                list_for_each_entry(child, &desc->txd.tx_list, desc_node)
+                        if (!(child->lli.ctrla & ATC_DONE))
+                                /* Currently in progress */
+                                return;
+
+                /*
+                 * No descriptors so far seem to be in progress, i.e.
+                 * this chain must be done.
+                 */
+                atc_chain_complete(atchan, desc);
+        }
+}
+
+/**
+ * atc_advance_work - at the end of a transaction, move forward
+ * @atchan: channel where the transaction ended
+ *
+ * Called with atchan->lock held and bh disabled
+ */
+static void atc_advance_work(struct at_dma_chan *atchan)
+{
+        dev_vdbg(chan2dev(&atchan->chan_common), "advance_work\n");
+
+        if (list_empty(&atchan->active_list) ||
+            list_is_singular(&atchan->active_list)) {
+                atc_complete_all(atchan);
+        } else {
+                atc_chain_complete(atchan, atc_first_active(atchan));
+                /* advance work */
+                atc_dostart(atchan, atc_first_active(atchan));
+        }
+}
+
+
+/**
+ * atc_handle_error - handle errors reported by DMA controller
+ * @atchan: channel where error occurs
+ *
+ * Called with atchan->lock held and bh disabled
+ */
+static void atc_handle_error(struct at_dma_chan *atchan)
+{
+        struct at_desc *bad_desc;
+        struct at_desc *child;
+
+        /*
+         * The descriptor currently at the head of the active list is
+         * broked. Since we don't have any way to report errors, we'll
+         * just have to scream loudly and try to carry on.
+         */
+        bad_desc = atc_first_active(atchan);
+        list_del_init(&bad_desc->desc_node);
+
+        /* As we are stopped, take advantage to push queued descriptors
+         * in active_list */
+        list_splice_init(&atchan->queue, atchan->active_list.prev);
+
+        /* Try to restart the controller */
+        if (!list_empty(&atchan->active_list))
+                atc_dostart(atchan, atc_first_active(atchan));
+
+        /*
+         * KERN_CRITICAL may seem harsh, but since this only happens
+         * when someone submits a bad physical address in a
+         * descriptor, we should consider ourselves lucky that the
+         * controller flagged an error instead of scribbling over
+         * random memory locations.
+         */
+        dev_crit(chan2dev(&atchan->chan_common),
+                        "Bad descriptor submitted for DMA!\n");
+        dev_crit(chan2dev(&atchan->chan_common),
+                        "  cookie: %d\n", bad_desc->txd.cookie);
+        atc_dump_lli(atchan, &bad_desc->lli);
+        list_for_each_entry(child, &bad_desc->txd.tx_list, desc_node)
+                atc_dump_lli(atchan, &child->lli);
+
+        /* Pretend the descriptor completed successfully */
+        atc_chain_complete(atchan, bad_desc);
+}
+
+
+/*--  IRQ & Tasklet  ---------------------------------------------------*/
+
+static void atc_tasklet(unsigned long data)
+{
+        struct at_dma_chan *atchan = (struct at_dma_chan *)data;
+
+        /* Channel cannot be enabled here */
+        if (atc_chan_is_enabled(atchan)) {
+                dev_err(chan2dev(&atchan->chan_common),
+                        "BUG: channel enabled in tasklet\n");
+                return;
+        }
+
+        spin_lock(&atchan->lock);
+        if (test_and_clear_bit(0, &atchan->error_status))
+                atc_handle_error(atchan);
+        else
+                atc_advance_work(atchan);
+
+        spin_unlock(&atchan->lock);
+}
+
+static irqreturn_t at_dma_interrupt(int irq, void *dev_id)
+{
+        struct at_dma           *atdma = (struct at_dma *)dev_id;
+        struct at_dma_chan      *atchan;
+        int                     i;
+        u32                     status, pending, imr;
+        int                     ret = IRQ_NONE;
+
+        do {
+                imr = dma_readl(atdma, EBCIMR);
+                status = dma_readl(atdma, EBCISR);
+                pending = status & imr;
+
+                if (!pending)
+                        break;
+
+                dev_vdbg(atdma->dma_common.dev,
+                        "interrupt: status = 0x%08x, 0x%08x, 0x%08x\n",
+                         status, imr, pending);
+
+                for (i = 0; i < atdma->dma_common.chancnt; i++) {
+                        atchan = &atdma->chan[i];
+                        if (pending & (AT_DMA_CBTC(i) | AT_DMA_ERR(i))) {
+                                if (pending & AT_DMA_ERR(i)) {
+                                        /* Disable channel on AHB error */
+                                        dma_writel(atdma, CHDR, atchan->mask);
+                                        /* Give information to tasklet */
+                                        set_bit(0, &atchan->error_status);
+                                }
+                                tasklet_schedule(&atchan->tasklet);
+                                ret = IRQ_HANDLED;
+                        }
+                }
+
+        } while (pending);
+
+        return ret;
+}
+
+
+/*--  DMA Engine API  --------------------------------------------------*/
+
+/**
+ * atc_tx_submit - set the prepared descriptor(s) to be executed by the engine
+ * @desc: descriptor at the head of the transaction chain
+ *
+ * Queue chain if DMA engine is working already
+ *
+ * Cookie increment and adding to active_list or queue must be atomic
+ */
+static dma_cookie_t atc_tx_submit(struct dma_async_tx_descriptor *tx)
+{
+        struct at_desc          *desc = txd_to_at_desc(tx);
+        struct at_dma_chan      *atchan = to_at_dma_chan(tx->chan);
+        dma_cookie_t            cookie;
+
+        spin_lock_bh(&atchan->lock);
+        cookie = atc_assign_cookie(atchan, desc);
+
+        if (list_empty(&atchan->active_list)) {
+                dev_vdbg(chan2dev(tx->chan), "tx_submit: started %u\n",
+                                desc->txd.cookie);
+                atc_dostart(atchan, desc);
+                list_add_tail(&desc->desc_node, &atchan->active_list);
+        } else {
+                dev_vdbg(chan2dev(tx->chan), "tx_submit: queued %u\n",
+                                desc->txd.cookie);
+                list_add_tail(&desc->desc_node, &atchan->queue);
+        }
+
+        spin_unlock_bh(&atchan->lock);
+
+        return cookie;
+}
+
+/**
+ * atc_prep_dma_memcpy - prepare a memcpy operation
+ * @chan: the channel to prepare operation on
+ * @dest: operation virtual destination address
+ * @src: operation virtual source address
+ * @len: operation length
+ * @flags: tx descriptor status flags
+ */
+static struct dma_async_tx_descriptor *
+atc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
+                size_t len, unsigned long flags)
+{
+        struct at_dma_chan      *atchan = to_at_dma_chan(chan);
+        struct at_desc          *desc = NULL;
+        struct at_desc          *first = NULL;
+        struct at_desc          *prev = NULL;
+        size_t                  xfer_count;
+        size_t                  offset;
+        unsigned int            src_width;
+        unsigned int            dst_width;
+        u32                     ctrla;
+        u32                     ctrlb;
+
+        dev_vdbg(chan2dev(chan), "prep_dma_memcpy: d0x%x s0x%x l0x%zx f0x%lx\n",
+                        dest, src, len, flags);
+
+        if (unlikely(!len)) {
+                dev_dbg(chan2dev(chan), "prep_dma_memcpy: length is zero!\n");
+                return NULL;
+        }
+
+        ctrla =   ATC_DEFAULT_CTRLA;
+        ctrlb =   ATC_DEFAULT_CTRLB
+                | ATC_SRC_ADDR_MODE_INCR
+                | ATC_DST_ADDR_MODE_INCR
+                | ATC_FC_MEM2MEM;
+
+        /*
+         * We can be a lot more clever here, but this should take care
+         * of the most common optimization.
+         */
+        if (!((src | dest  | len) & 3)) {
+                ctrla |= ATC_SRC_WIDTH_WORD | ATC_DST_WIDTH_WORD;
+                src_width = dst_width = 2;
+        } else if (!((src | dest | len) & 1)) {
+                ctrla |= ATC_SRC_WIDTH_HALFWORD | ATC_DST_WIDTH_HALFWORD;
+                src_width = dst_width = 1;
+        } else {
+                ctrla |= ATC_SRC_WIDTH_BYTE | ATC_DST_WIDTH_BYTE;
+                src_width = dst_width = 0;
+        }
+
+        for (offset = 0; offset < len; offset += xfer_count << src_width) {
+                xfer_count = min_t(size_t, (len - offset) >> src_width,
+                                ATC_BTSIZE_MAX);
+
+                desc = atc_desc_get(atchan);
+                if (!desc)
+                        goto err_desc_get;
+
+                desc->lli.saddr = src + offset;
+                desc->lli.daddr = dest + offset;
+                desc->lli.ctrla = ctrla | xfer_count;
+                desc->lli.ctrlb = ctrlb;
+
+                desc->txd.cookie = 0;
+                async_tx_ack(&desc->txd);
+
+                if (!first) {
+                        first = desc;
+                } else {
+                        /* inform the HW lli about chaining */
+                        prev->lli.dscr = desc->txd.phys;
+                        /* insert the link descriptor to the LD ring */
+                        list_add_tail(&desc->desc_node,
+                                        &first->txd.tx_list);
+                }
+                prev = desc;
+        }
+
+        /* First descriptor of the chain embedds additional information */
+        first->txd.cookie = -EBUSY;
+        first->len = len;
+
+        /* set end-of-link to the last link descriptor of list*/
+        set_desc_eol(desc);
+
+        desc->txd.flags = flags; /* client is in control of this ack */
+
+        return &first->txd;
+
+err_desc_get:
+        atc_desc_put(atchan, first);
+        return NULL;
+}
+
+
+/**
+ * atc_prep_slave_sg - prepare descriptors for a DMA_SLAVE transaction
+ * @chan: DMA channel
+ * @sgl: scatterlist to transfer to/from
+ * @sg_len: number of entries in @scatterlist
+ * @direction: DMA direction
+ * @flags: tx descriptor status flags
+ */
+static struct dma_async_tx_descriptor *
+atc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
+                unsigned int sg_len, enum dma_data_direction direction,
+                unsigned long flags)
+{
+        struct at_dma_chan      *atchan = to_at_dma_chan(chan);
+        struct at_dma_slave     *atslave = chan->private;
+        struct at_desc          *first = NULL;
+        struct at_desc          *prev = NULL;
+        u32                     ctrla;
+        u32                     ctrlb;
+        dma_addr_t              reg;
+        unsigned int            reg_width;
+        unsigned int            mem_width;
+        unsigned int            i;
+        struct scatterlist      *sg;
+        size_t                  total_len = 0;
+
+        dev_vdbg(chan2dev(chan), "prep_slave_sg: %s f0x%lx\n",
+                        direction == DMA_TO_DEVICE ? "TO DEVICE" : "FROM DEVICE",
+                        flags);
+
+        if (unlikely(!atslave || !sg_len)) {
+                dev_dbg(chan2dev(chan), "prep_dma_memcpy: length is zero!\n");
+                return NULL;
+        }
+
+        reg_width = atslave->reg_width;
+
+        sg_len = dma_map_sg(chan2parent(chan), sgl, sg_len, direction);
+
+        ctrla = ATC_DEFAULT_CTRLA | atslave->ctrla;
+        ctrlb = ATC_DEFAULT_CTRLB | ATC_IEN;
+
+        switch (direction) {
+        case DMA_TO_DEVICE:
+                ctrla |=  ATC_DST_WIDTH(reg_width);
+                ctrlb |=  ATC_DST_ADDR_MODE_FIXED
+                        | ATC_SRC_ADDR_MODE_INCR
+                        | ATC_FC_MEM2PER;
+                reg = atslave->tx_reg;
+                for_each_sg(sgl, sg, sg_len, i) {
+                        struct at_desc  *desc;
+                        u32             len;
+                        u32             mem;
+
+                        desc = atc_desc_get(atchan);
+                        if (!desc)
+                                goto err_desc_get;
+
+                        mem = sg_phys(sg);
+                        len = sg_dma_len(sg);
+                        mem_width = 2;
+                        if (unlikely(mem & 3 || len & 3))
+                                mem_width = 0;
+
+                        desc->lli.saddr = mem;
+                        desc->lli.daddr = reg;
+                        desc->lli.ctrla = ctrla
+                                        | ATC_SRC_WIDTH(mem_width)
+                                        | len >> mem_width;
+                        desc->lli.ctrlb = ctrlb;
+
+                        if (!first) {
+                                first = desc;
+                        } else {
+                                /* inform the HW lli about chaining */
+                                prev->lli.dscr = desc->txd.phys;
+                                /* insert the link descriptor to the LD ring */
+                                list_add_tail(&desc->desc_node,
+                                                &first->txd.tx_list);
+                        }
+                        prev = desc;
+                        total_len += len;
+                }
+                break;
+        case DMA_FROM_DEVICE:
+                ctrla |=  ATC_SRC_WIDTH(reg_width);
+                ctrlb |=  ATC_DST_ADDR_MODE_INCR
+                        | ATC_SRC_ADDR_MODE_FIXED
+                        | ATC_FC_PER2MEM;
+
+                reg = atslave->rx_reg;
+                for_each_sg(sgl, sg, sg_len, i) {
+                        struct at_desc  *desc;
+                        u32             len;
+                        u32             mem;
+
+                        desc = atc_desc_get(atchan);
+                        if (!desc)
+                                goto err_desc_get;
+
+                        mem = sg_phys(sg);
+                        len = sg_dma_len(sg);
+                        mem_width = 2;
+                        if (unlikely(mem & 3 || len & 3))
+                                mem_width = 0;
+
+                        desc->lli.saddr = reg;
+                        desc->lli.daddr = mem;
+                        desc->lli.ctrla = ctrla
+                                        | ATC_DST_WIDTH(mem_width)
+                                        | len >> mem_width;
+                        desc->lli.ctrlb = ctrlb;
+
+                        if (!first) {
+                                first = desc;
+                        } else {
+                                /* inform the HW lli about chaining */
+                                prev->lli.dscr = desc->txd.phys;
+                                /* insert the link descriptor to the LD ring */
+                                list_add_tail(&desc->desc_node,
+                                                &first->txd.tx_list);
+                        }
+                        prev = desc;
+                        total_len += len;
+                }
+                break;
+        default:
+                return NULL;
+        }
+
+        /* set end-of-link to the last link descriptor of list*/
+        set_desc_eol(prev);
+
+        /* First descriptor of the chain embedds additional information */
+        first->txd.cookie = -EBUSY;
+        first->len = total_len;
+
+        /* last link descriptor of list is responsible of flags */
+        prev->txd.flags = flags; /* client is in control of this ack */
+
+        return &first->txd;
+
+err_desc_get:
+        dev_err(chan2dev(chan), "not enough descriptors available\n");
+        atc_desc_put(atchan, first);
+        return NULL;
+}
+
+static void atc_terminate_all(struct dma_chan *chan)
+{
+        struct at_dma_chan      *atchan = to_at_dma_chan(chan);
+        struct at_dma           *atdma = to_at_dma(chan->device);
+        struct at_desc          *desc, *_desc;
+        LIST_HEAD(list);
+
+        /*
+         * This is only called when something went wrong elsewhere, so
+         * we don't really care about the data. Just disable the
+         * channel. We still have to poll the channel enable bit due
+         * to AHB/HSB limitations.
+         */
+        spin_lock_bh(&atchan->lock);
+
+        dma_writel(atdma, CHDR, atchan->mask);
+
+        /* confirm that this channel is disabled */
+        while (dma_readl(atdma, CHSR) & atchan->mask)
+                cpu_relax();
+
+        /* active_list entries will end up before queued entries */
+        list_splice_init(&atchan->queue, &list);
+        list_splice_init(&atchan->active_list, &list);
+
+        spin_unlock_bh(&atchan->lock);
+
+        /* Flush all pending and queued descriptors */
+        list_for_each_entry_safe(desc, _desc, &list, desc_node)
+                atc_chain_complete(atchan, desc);
+}
+
+/**
+ * atc_is_tx_complete - poll for transaction completion
+ * @chan: DMA channel
+ * @cookie: transaction identifier to check status of
+ * @done: if not %NULL, updated with last completed transaction
+ * @used: if not %NULL, updated with last used transaction
+ *
+ * If @done and @used are passed in, upon return they reflect the driver
+ * internal state and can be used with dma_async_is_complete() to check
+ * the status of multiple cookies without re-checking hardware state.
+ */
+static enum dma_status
+atc_is_tx_complete(struct dma_chan *chan,
+                dma_cookie_t cookie,
+                dma_cookie_t *done, dma_cookie_t *used)
+{
+        struct at_dma_chan      *atchan = to_at_dma_chan(chan);
+        dma_cookie_t            last_used;
+        dma_cookie_t            last_complete;
+        enum dma_status         ret;
+
+        dev_vdbg(chan2dev(chan), "is_tx_complete: %d (d%d, u%d)\n",
+                        cookie, done ? *done : 0, used ? *used : 0);
+
+        spin_lock_bh(atchan->lock);
+
+        last_complete = atchan->completed_cookie;
+        last_used = chan->cookie;
+
+        ret = dma_async_is_complete(cookie, last_complete, last_used);
+        if (ret != DMA_SUCCESS) {
+                atc_cleanup_descriptors(atchan);
+
+                last_complete = atchan->completed_cookie;
+                last_used = chan->cookie;
+
+                ret = dma_async_is_complete(cookie, last_complete, last_used);
+        }
+
+        spin_unlock_bh(atchan->lock);
+
+        if (done)
+                *done = last_complete;
+        if (used)
+                *used = last_used;
+
+        return ret;
+}
+
+/**
+ * atc_issue_pending - try to finish work
+ * @chan: target DMA channel
+ */
+static void atc_issue_pending(struct dma_chan *chan)
+{
+        struct at_dma_chan      *atchan = to_at_dma_chan(chan);
+
+        dev_vdbg(chan2dev(chan), "issue_pending\n");
+
+        if (!atc_chan_is_enabled(atchan)) {
+                spin_lock_bh(&atchan->lock);
+                atc_advance_work(atchan);
+                spin_unlock_bh(&atchan->lock);
+        }
+}
+
+/**
+ * atc_alloc_chan_resources - allocate resources for DMA channel
+ * @chan: allocate descriptor resources for this channel
+ * @client: current client requesting the channel be ready for requests
+ *
+ * return - the number of allocated descriptors
+ */
+static int atc_alloc_chan_resources(struct dma_chan *chan)
+{
+        struct at_dma_chan      *atchan = to_at_dma_chan(chan);
+        struct at_dma           *atdma = to_at_dma(chan->device);
+        struct at_desc          *desc;
+        struct at_dma_slave     *atslave;
+        int                     i;
+        u32                     cfg;
+        LIST_HEAD(tmp_list);
+
+        dev_vdbg(chan2dev(chan), "alloc_chan_resources\n");
+
+        /* ASSERT:  channel is idle */
+        if (atc_chan_is_enabled(atchan)) {
+                dev_dbg(chan2dev(chan), "DMA channel not idle ?\n");
+                return -EIO;
+        }
+
+        cfg = ATC_DEFAULT_CFG;
+
+        atslave = chan->private;
+        if (atslave) {
+                /*
+                 * We need controller-specific data to set up slave
+                 * transfers.
+                 */
+                BUG_ON(!atslave->dma_dev || atslave->dma_dev != atdma->dma_common.dev);
+
+                /* if cfg configuration specified take it instad of default */
+                if (atslave->cfg)
+                        cfg = atslave->cfg;
+        }
+
+        /* have we already been set up?
+         * reconfigure channel but no need to reallocate descriptors */
+        if (!list_empty(&atchan->free_list))
+                return atchan->descs_allocated;
+
+        /* Allocate initial pool of descriptors */
+        for (i = 0; i < init_nr_desc_per_channel; i++) {
+                desc = atc_alloc_descriptor(chan, GFP_KERNEL);
+                if (!desc) {
+                        dev_err(atdma->dma_common.dev,
+                                "Only %d initial descriptors\n", i);
+                        break;
+                }
+                list_add_tail(&desc->desc_node, &tmp_list);
+        }
+
+        spin_lock_bh(&atchan->lock);
+        atchan->descs_allocated = i;
+        list_splice(&tmp_list, &atchan->free_list);
+        atchan->completed_cookie = chan->cookie = 1;
+        spin_unlock_bh(&atchan->lock);
+
+        /* channel parameters */
+        channel_writel(atchan, CFG, cfg);
+
+        dev_dbg(chan2dev(chan),
+                "alloc_chan_resources: allocated %d descriptors\n",
+                atchan->descs_allocated);
+
+        return atchan->descs_allocated;
+}
+
+/**
+ * atc_free_chan_resources - free all channel resources
+ * @chan: DMA channel
+ */
+static void atc_free_chan_resources(struct dma_chan *chan)
+{
+        struct at_dma_chan      *atchan = to_at_dma_chan(chan);
+        struct at_dma           *atdma = to_at_dma(chan->device);
+        struct at_desc          *desc, *_desc;
+        LIST_HEAD(list);
+
+        dev_dbg(chan2dev(chan), "free_chan_resources: (descs allocated=%u)\n",
+                atchan->descs_allocated);
+
+        /* ASSERT:  channel is idle */
+        BUG_ON(!list_empty(&atchan->active_list));
+        BUG_ON(!list_empty(&atchan->queue));
+        BUG_ON(atc_chan_is_enabled(atchan));
+
+        list_for_each_entry_safe(desc, _desc, &atchan->free_list, desc_node) {
+                dev_vdbg(chan2dev(chan), "  freeing descriptor %p\n", desc);
+                list_del(&desc->desc_node);
+                /* free link descriptor */
+                dma_pool_free(atdma->dma_desc_pool, desc, desc->txd.phys);
+        }
+        list_splice_init(&atchan->free_list, &list);
+        atchan->descs_allocated = 0;
+
+        dev_vdbg(chan2dev(chan), "free_chan_resources: done\n");
+}
+
+
+/*--  Module Management  -----------------------------------------------*/
+
+/**
+ * at_dma_off - disable DMA controller
+ * @atdma: the Atmel HDAMC device
+ */
+static void at_dma_off(struct at_dma *atdma)
+{
+        dma_writel(atdma, EN, 0);
+
+        /* disable all interrupts */
+        dma_writel(atdma, EBCIDR, -1L);
+
+        /* confirm that all channels are disabled */
+        while (dma_readl(atdma, CHSR) & atdma->all_chan_mask)
+                cpu_relax();
+}
+
+static int __init at_dma_probe(struct platform_device *pdev)
+{
+        struct at_dma_platform_data *pdata;
+        struct resource         *io;
+        struct at_dma           *atdma;
+        size_t                  size;
+        int                     irq;
+        int                     err;
+        int                     i;
+
+        /* get DMA Controller parameters from platform */
+        pdata = pdev->dev.platform_data;
+        if (!pdata || pdata->nr_channels > AT_DMA_MAX_NR_CHANNELS)
+                return -EINVAL;
+
+        io = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        if (!io)
+                return -EINVAL;
+
+        irq = platform_get_irq(pdev, 0);
+        if (irq < 0)
+                return irq;
+
+        size = sizeof(struct at_dma);
+        size += pdata->nr_channels * sizeof(struct at_dma_chan);
+        atdma = kzalloc(size, GFP_KERNEL);
+        if (!atdma)
+                return -ENOMEM;
+
+        /* discover transaction capabilites from the platform data */
+        atdma->dma_common.cap_mask = pdata->cap_mask;
+        atdma->all_chan_mask = (1 << pdata->nr_channels) - 1;
+
+        size = io->end - io->start + 1;
+        if (!request_mem_region(io->start, size, pdev->dev.driver->name)) {
+                err = -EBUSY;
+                goto err_kfree;
+        }
+
+        atdma->regs = ioremap(io->start, size);
+        if (!atdma->regs) {
+                err = -ENOMEM;
+                goto err_release_r;
+        }
+
+        atdma->clk = clk_get(&pdev->dev, "dma_clk");
+        if (IS_ERR(atdma->clk)) {
+                err = PTR_ERR(atdma->clk);
+                goto err_clk;
+        }
+        clk_enable(atdma->clk);
+
+        /* force dma off, just in case */
+        at_dma_off(atdma);
+
+        err = request_irq(irq, at_dma_interrupt, 0, "at_hdmac", atdma);
+        if (err)
+                goto err_irq;
+
+        platform_set_drvdata(pdev, atdma);
+
+        /* create a pool of consistent memory blocks for hardware descriptors */
+        atdma->dma_desc_pool = dma_pool_create("at_hdmac_desc_pool",
+                        &pdev->dev, sizeof(struct at_desc),
+                        4 /* word alignment */, 0);
+        if (!atdma->dma_desc_pool) {
+                dev_err(&pdev->dev, "No memory for descriptors dma pool\n");
+                err = -ENOMEM;
+                goto err_pool_create;
+        }
+
+        /* clear any pending interrupt */
+        while (dma_readl(atdma, EBCISR))
+                cpu_relax();
+
+        /* initialize channels related values */
+        INIT_LIST_HEAD(&atdma->dma_common.channels);
+        for (i = 0; i < pdata->nr_channels; i++, atdma->dma_common.chancnt++) {
+                struct at_dma_chan      *atchan = &atdma->chan[i];
+
+                atchan->chan_common.device = &atdma->dma_common;
+                atchan->chan_common.cookie = atchan->completed_cookie = 1;
+                atchan->chan_common.chan_id = i;
+                list_add_tail(&atchan->chan_common.device_node,
+                                &atdma->dma_common.channels);
+
+                atchan->ch_regs = atdma->regs + ch_regs(i);
+                spin_lock_init(&atchan->lock);
+                atchan->mask = 1 << i;
+
+                INIT_LIST_HEAD(&atchan->active_list);
+                INIT_LIST_HEAD(&atchan->queue);
+                INIT_LIST_HEAD(&atchan->free_list);
+
+                tasklet_init(&atchan->tasklet, atc_tasklet,
+                                (unsigned long)atchan);
+                atc_enable_irq(atchan);
+        }
+
+        /* set base routines */
+        atdma->dma_common.device_alloc_chan_resources = atc_alloc_chan_resources;
+        atdma->dma_common.device_free_chan_resources = atc_free_chan_resources;
+        atdma->dma_common.device_is_tx_complete = atc_is_tx_complete;
+        atdma->dma_common.device_issue_pending = atc_issue_pending;
+        atdma->dma_common.dev = &pdev->dev;
+
+        /* set prep routines based on capability */
+        if (dma_has_cap(DMA_MEMCPY, atdma->dma_common.cap_mask))
+                atdma->dma_common.device_prep_dma_memcpy = atc_prep_dma_memcpy;
+
+        if (dma_has_cap(DMA_SLAVE, atdma->dma_common.cap_mask)) {
+                atdma->dma_common.device_prep_slave_sg = atc_prep_slave_sg;
+                atdma->dma_common.device_terminate_all = atc_terminate_all;
+        }
+
+        dma_writel(atdma, EN, AT_DMA_ENABLE);
+
+        dev_info(&pdev->dev, "Atmel AHB DMA Controller ( %s%s), %d channels\n",
+          dma_has_cap(DMA_MEMCPY, atdma->dma_common.cap_mask) ? "cpy " : "",
+          dma_has_cap(DMA_SLAVE, atdma->dma_common.cap_mask)  ? "slave " : "",
+          atdma->dma_common.chancnt);
+
+        dma_async_device_register(&atdma->dma_common);
+
+        return 0;
+
+err_pool_create:
+        platform_set_drvdata(pdev, NULL);
+        free_irq(platform_get_irq(pdev, 0), atdma);
+err_irq:
+        clk_disable(atdma->clk);
+        clk_put(atdma->clk);
+err_clk:
+        iounmap(atdma->regs);
+        atdma->regs = NULL;
+err_release_r:
+        release_mem_region(io->start, size);
+err_kfree:
+        kfree(atdma);
+        return err;
+}
+
+static int __exit at_dma_remove(struct platform_device *pdev)
+{
+        struct at_dma           *atdma = platform_get_drvdata(pdev);
+        struct dma_chan         *chan, *_chan;
+        struct resource         *io;
+
+        at_dma_off(atdma);
+        dma_async_device_unregister(&atdma->dma_common);
+
+        dma_pool_destroy(atdma->dma_desc_pool);
+        platform_set_drvdata(pdev, NULL);
+        free_irq(platform_get_irq(pdev, 0), atdma);
+
+        list_for_each_entry_safe(chan, _chan, &atdma->dma_common.channels,
+                        device_node) {
+                struct at_dma_chan      *atchan = to_at_dma_chan(chan);
+
+                /* Disable interrupts */
+                atc_disable_irq(atchan);
+                tasklet_disable(&atchan->tasklet);
+
+                tasklet_kill(&atchan->tasklet);
+                list_del(&chan->device_node);
+        }
+
+        clk_disable(atdma->clk);
+        clk_put(atdma->clk);
+
+        iounmap(atdma->regs);
+        atdma->regs = NULL;
+
+        io = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        release_mem_region(io->start, io->end - io->start + 1);
+
+        kfree(atdma);
+
+        return 0;
+}
+
+static void at_dma_shutdown(struct platform_device *pdev)
+{
+        struct at_dma   *atdma = platform_get_drvdata(pdev);
+
+        at_dma_off(platform_get_drvdata(pdev));
+        clk_disable(atdma->clk);
+}
+
+static int at_dma_suspend_late(struct platform_device *pdev, pm_message_t mesg)
+{
+        struct at_dma   *atdma = platform_get_drvdata(pdev);
+
+        at_dma_off(platform_get_drvdata(pdev));
+        clk_disable(atdma->clk);
+        return 0;
+}
+
+static int at_dma_resume_early(struct platform_device *pdev)
+{
+        struct at_dma   *atdma = platform_get_drvdata(pdev);
+
+        clk_enable(atdma->clk);
+        dma_writel(atdma, EN, AT_DMA_ENABLE);
+        return 0;
+
+}
+
+static struct platform_driver at_dma_driver = {
+        .remove         = __exit_p(at_dma_remove),
+        .shutdown       = at_dma_shutdown,
+        .suspend_late   = at_dma_suspend_late,
+        .resume_early   = at_dma_resume_early,
+        .driver = {
+                .name   = "at_hdmac",
+        },
+};
+
+static int __init at_dma_init(void)
+{
+        return platform_driver_probe(&at_dma_driver, at_dma_probe);
+}
+module_init(at_dma_init);
+
+static void __exit at_dma_exit(void)
+{
+        platform_driver_unregister(&at_dma_driver);
+}
+module_exit(at_dma_exit);
+
+MODULE_DESCRIPTION("Atmel AHB DMA Controller driver");
+MODULE_AUTHOR("Nicolas Ferre <nicolas.ferre@atmel.com>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:at_hdmac");