Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 1210 insertions, 0 deletions

diff --git a/arch/arm/mach-s3c2410/dma.c b/arch/arm/mach-s3c2410/dma.c
new file mode 100644
index 000000000000..bc229fab86d4
--- /dev/null
+++ b/arch/arm/mach-s3c2410/dma.c
@@ -0,0 +1,1210 @@
+/* linux/arch/arm/mach-bast/dma.c
+ *
+ * (c) 2003-2005 Simtec Electronics
+ *      Ben Dooks <ben@simtec.co.uk>
+ *
+ * S3C2410 DMA core
+ *
+ * http://www.simtec.co.uk/products/EB2410ITX/
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Changelog:
+ *  27-Feb-2005 BJD  Added kmem cache for dma descriptors
+ *  18-Nov-2004 BJD  Removed error for loading onto stopped channel
+ *  10-Nov-2004 BJD  Ensure all external symbols exported for modules
+ *  10-Nov-2004 BJD  Use sys_device and sysdev_class for power management
+ *  08-Aug-2004 BJD  Apply rmk's suggestions
+ *  21-Jul-2004 BJD  Ported to linux 2.6
+ *  12-Jul-2004 BJD  Finished re-write and change of API
+ *  06-Jul-2004 BJD  Rewrote dma code to try and cope with various problems
+ *  23-May-2003 BJD  Created file
+ *  19-Aug-2003 BJD  Cleanup, header fix, added URL
+ *
+ * This file is based on the Sangwook Lee/Samsung patches, re-written due
+ * to various ommisions from the code (such as flexible dma configuration)
+ * for use with the BAST system board.
+ *
+ * The re-write is pretty much complete, and should be good enough for any
+ * possible DMA function
+ */
+
+#include <linux/config.h>
+
+#ifdef CONFIG_S3C2410_DMA_DEBUG
+#define DEBUG
+#endif
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/interrupt.h>
+#include <linux/sysdev.h>
+#include <linux/slab.h>
+#include <linux/errno.h>
+#include <linux/delay.h>
+
+#include <asm/system.h>
+#include <asm/irq.h>
+#include <asm/hardware.h>
+#include <asm/io.h>
+#include <asm/dma.h>
+
+#include <asm/mach/dma.h>
+#include <asm/arch/map.h>
+
+/* io map for dma */
+static void __iomem *dma_base;
+static kmem_cache_t *dma_kmem;
+
+/* dma channel state information */
+s3c2410_dma_chan_t s3c2410_chans[S3C2410_DMA_CHANNELS];
+
+/* debugging functions */
+
+#define BUF_MAGIC (0xcafebabe)
+
+#define dmawarn(fmt...) printk(KERN_DEBUG fmt)
+
+#define dma_regaddr(chan, reg) ((chan)->regs + (reg))
+
+#if 1
+#define dma_wrreg(chan, reg, val) writel((val), (chan)->regs + (reg))
+#else
+static inline void
+dma_wrreg(s3c2410_dma_chan_t *chan, int reg, unsigned long val)
+{
+        pr_debug("writing %08x to register %08x\n",(unsigned int)val,reg);
+        writel(val, dma_regaddr(chan, reg));
+}
+
+#endif
+
+#define dma_rdreg(chan, reg) readl((chan)->regs + (reg))
+
+/* captured register state for debug */
+
+struct s3c2410_dma_regstate {
+        unsigned long         dcsrc;
+        unsigned long         disrc;
+        unsigned long         dstat;
+        unsigned long         dcon;
+        unsigned long         dmsktrig;
+};
+
+#ifdef CONFIG_S3C2410_DMA_DEBUG
+
+/* dmadbg_showregs
+ *
+ * simple debug routine to print the current state of the dma registers
+*/
+
+static void
+dmadbg_capture(s3c2410_dma_chan_t *chan, struct s3c2410_dma_regstate *regs)
+{
+        regs->dcsrc    = dma_rdreg(chan, S3C2410_DMA_DCSRC);
+        regs->disrc    = dma_rdreg(chan, S3C2410_DMA_DISRC);
+        regs->dstat    = dma_rdreg(chan, S3C2410_DMA_DSTAT);
+        regs->dcon     = dma_rdreg(chan, S3C2410_DMA_DCON);
+        regs->dmsktrig = dma_rdreg(chan, S3C2410_DMA_DMASKTRIG);
+}
+
+static void
+dmadbg_showregs(const char *fname, int line, s3c2410_dma_chan_t *chan,
+                 struct s3c2410_dma_regstate *regs)
+{
+        printk(KERN_DEBUG "dma%d: %s:%d: DCSRC=%08lx, DISRC=%08lx, DSTAT=%08lx DMT=%02lx, DCON=%08lx\n",
+               chan->number, fname, line,
+               regs->dcsrc, regs->disrc, regs->dstat, regs->dmsktrig,
+               regs->dcon);
+}
+
+static void
+dmadbg_showchan(const char *fname, int line, s3c2410_dma_chan_t *chan)
+{
+        struct s3c2410_dma_regstate state;
+
+        dmadbg_capture(chan, &state);
+
+        printk(KERN_DEBUG "dma%d: %s:%d: ls=%d, cur=%p, %p %p\n",
+               chan->number, fname, line, chan->load_state,
+               chan->curr, chan->next, chan->end);
+
+        dmadbg_showregs(fname, line, chan, &state);
+}
+
+#define dbg_showregs(chan) dmadbg_showregs(__FUNCTION__, __LINE__, (chan))
+#define dbg_showchan(chan) dmadbg_showchan(__FUNCTION__, __LINE__, (chan))
+#else
+#define dbg_showregs(chan) do { } while(0)
+#define dbg_showchan(chan) do { } while(0)
+#endif /* CONFIG_S3C2410_DMA_DEBUG */
+
+#define check_channel(chan) \
+  do { if ((chan) >= S3C2410_DMA_CHANNELS) { \
+    printk(KERN_ERR "%s: invalid channel %d\n", __FUNCTION__, (chan)); \
+    return -EINVAL; \
+  } } while(0)
+
+
+/* s3c2410_dma_stats_timeout
+ *
+ * Update DMA stats from timeout info
+*/
+
+static void
+s3c2410_dma_stats_timeout(s3c2410_dma_stats_t *stats, int val)
+{
+        if (stats == NULL)
+                return;
+
+        if (val > stats->timeout_longest)
+                stats->timeout_longest = val;
+        if (val < stats->timeout_shortest)
+                stats->timeout_shortest = val;
+
+        stats->timeout_avg += val;
+}
+
+/* s3c2410_dma_waitforload
+ *
+ * wait for the DMA engine to load a buffer, and update the state accordingly
+*/
+
+static int
+s3c2410_dma_waitforload(s3c2410_dma_chan_t *chan, int line)
+{
+        int timeout = chan->load_timeout;
+        int took;
+
+        if (chan->load_state != S3C2410_DMALOAD_1LOADED) {
+                printk(KERN_ERR "dma%d: s3c2410_dma_waitforload() called in loadstate %d from line %d\n", chan->number, chan->load_state, line);
+                return 0;
+        }
+
+        if (chan->stats != NULL)
+                chan->stats->loads++;
+
+        while (--timeout > 0) {
+                if ((dma_rdreg(chan, S3C2410_DMA_DSTAT) << (32-20)) != 0) {
+                        took = chan->load_timeout - timeout;
+
+                        s3c2410_dma_stats_timeout(chan->stats, took);
+
+                        switch (chan->load_state) {
+                        case S3C2410_DMALOAD_1LOADED:
+                                chan->load_state = S3C2410_DMALOAD_1RUNNING;
+                                break;
+
+                        default:
+                                printk(KERN_ERR "dma%d: unknown load_state in s3c2410_dma_waitforload() %d\n", chan->number, chan->load_state);
+                        }
+
+                        return 1;
+                }
+        }
+
+        if (chan->stats != NULL) {
+                chan->stats->timeout_failed++;
+        }
+
+        return 0;
+}
+
+
+
+/* s3c2410_dma_loadbuffer
+ *
+ * load a buffer, and update the channel state
+*/
+
+static inline int
+s3c2410_dma_loadbuffer(s3c2410_dma_chan_t *chan,
+                       s3c2410_dma_buf_t *buf)
+{
+        unsigned long reload;
+
+        pr_debug("s3c2410_chan_loadbuffer: loading buff %p (0x%08lx,0x%06x)\n",
+                 buf, (unsigned long)buf->data, buf->size);
+
+        if (buf == NULL) {
+                dmawarn("buffer is NULL\n");
+                return -EINVAL;
+        }
+
+        /* check the state of the channel before we do anything */
+
+        if (chan->load_state == S3C2410_DMALOAD_1LOADED) {
+                dmawarn("load_state is S3C2410_DMALOAD_1LOADED\n");
+        }
+
+        if (chan->load_state == S3C2410_DMALOAD_1LOADED_1RUNNING) {
+                dmawarn("state is S3C2410_DMALOAD_1LOADED_1RUNNING\n");
+        }
+
+        /* it would seem sensible if we are the last buffer to not bother
+         * with the auto-reload bit, so that the DMA engine will not try
+         * and load another transfer after this one has finished...
+         */
+        if (chan->load_state == S3C2410_DMALOAD_NONE) {
+                pr_debug("load_state is none, checking for noreload (next=%p)\n",
+                         buf->next);
+                reload = (buf->next == NULL) ? S3C2410_DCON_NORELOAD : 0;
+        } else {
+                pr_debug("load_state is %d => autoreload\n", chan->load_state);
+                reload = S3C2410_DCON_AUTORELOAD;
+        }
+
+        writel(buf->data, chan->addr_reg);
+
+        dma_wrreg(chan, S3C2410_DMA_DCON,
+                  chan->dcon | reload | (buf->size/chan->xfer_unit));
+
+        chan->next = buf->next;
+
+        /* update the state of the channel */
+
+        switch (chan->load_state) {
+        case S3C2410_DMALOAD_NONE:
+                chan->load_state = S3C2410_DMALOAD_1LOADED;
+                break;
+
+        case S3C2410_DMALOAD_1RUNNING:
+                chan->load_state = S3C2410_DMALOAD_1LOADED_1RUNNING;
+                break;
+
+        default:
+                dmawarn("dmaload: unknown state %d in loadbuffer\n",
+                        chan->load_state);
+                break;
+        }
+
+        return 0;
+}
+
+/* s3c2410_dma_call_op
+ *
+ * small routine to call the op routine with the given op if it has been
+ * registered
+*/
+
+static void
+s3c2410_dma_call_op(s3c2410_dma_chan_t *chan, s3c2410_chan_op_t op)
+{
+        if (chan->op_fn != NULL) {
+                (chan->op_fn)(chan, op);
+        }
+}
+
+/* s3c2410_dma_buffdone
+ *
+ * small wrapper to check if callback routine needs to be called, and
+ * if so, call it
+*/
+
+static inline void
+s3c2410_dma_buffdone(s3c2410_dma_chan_t *chan, s3c2410_dma_buf_t *buf,
+                     s3c2410_dma_buffresult_t result)
+{
+        pr_debug("callback_fn=%p, buf=%p, id=%p, size=%d, result=%d\n",
+                 chan->callback_fn, buf, buf->id, buf->size, result);
+
+        if (chan->callback_fn != NULL) {
+                (chan->callback_fn)(chan, buf->id, buf->size, result);
+        }
+}
+
+/* s3c2410_dma_start
+ *
+ * start a dma channel going
+*/
+
+static int s3c2410_dma_start(s3c2410_dma_chan_t *chan)
+{
+        unsigned long tmp;
+        unsigned long flags;
+
+        pr_debug("s3c2410_start_dma: channel=%d\n", chan->number);
+
+        local_irq_save(flags);
+
+        if (chan->state == S3C2410_DMA_RUNNING) {
+                pr_debug("s3c2410_start_dma: already running (%d)\n", chan->state);
+                local_irq_restore(flags);
+                return 0;
+        }
+
+        chan->state = S3C2410_DMA_RUNNING;
+
+        /* check wether there is anything to load, and if not, see
+         * if we can find anything to load
+         */
+
+        if (chan->load_state == S3C2410_DMALOAD_NONE) {
+                if (chan->next == NULL) {
+                        printk(KERN_ERR "dma%d: channel has nothing loaded\n",
+                               chan->number);
+                        chan->state = S3C2410_DMA_IDLE;
+                        local_irq_restore(flags);
+                        return -EINVAL;
+                }
+
+                s3c2410_dma_loadbuffer(chan, chan->next);
+        }
+
+        dbg_showchan(chan);
+
+        /* enable the channel */
+
+        if (!chan->irq_enabled) {
+                enable_irq(chan->irq);
+                chan->irq_enabled = 1;
+        }
+
+        /* start the channel going */
+
+        tmp = dma_rdreg(chan, S3C2410_DMA_DMASKTRIG);
+        tmp &= ~S3C2410_DMASKTRIG_STOP;
+        tmp |= S3C2410_DMASKTRIG_ON;
+        dma_wrreg(chan, S3C2410_DMA_DMASKTRIG, tmp);
+
+        pr_debug("wrote %08lx to DMASKTRIG\n", tmp);
+
+#if 0
+        /* the dma buffer loads should take care of clearing the AUTO
+         * reloading feature */
+        tmp = dma_rdreg(chan, S3C2410_DMA_DCON);
+        tmp &= ~S3C2410_DCON_NORELOAD;
+        dma_wrreg(chan, S3C2410_DMA_DCON, tmp);
+#endif
+
+        s3c2410_dma_call_op(chan, S3C2410_DMAOP_START);
+
+        dbg_showchan(chan);
+
+        local_irq_restore(flags);
+        return 0;
+}
+
+/* s3c2410_dma_canload
+ *
+ * work out if we can queue another buffer into the DMA engine
+*/
+
+static int
+s3c2410_dma_canload(s3c2410_dma_chan_t *chan)
+{
+        if (chan->load_state == S3C2410_DMALOAD_NONE ||
+            chan->load_state == S3C2410_DMALOAD_1RUNNING)
+                return 1;
+
+        return 0;
+}
+
+
+/* s3c2410_dma_enqueue
+ *
+ * queue an given buffer for dma transfer.
+ *
+ * id         the device driver's id information for this buffer
+ * data       the physical address of the buffer data
+ * size       the size of the buffer in bytes
+ *
+ * If the channel is not running, then the flag S3C2410_DMAF_AUTOSTART
+ * is checked, and if set, the channel is started. If this flag isn't set,
+ * then an error will be returned.
+ *
+ * It is possible to queue more than one DMA buffer onto a channel at
+ * once, and the code will deal with the re-loading of the next buffer
+ * when necessary.
+*/
+
+int s3c2410_dma_enqueue(unsigned int channel, void *id,
+                        dma_addr_t data, int size)
+{
+        s3c2410_dma_chan_t *chan = &s3c2410_chans[channel];
+        s3c2410_dma_buf_t *buf;
+        unsigned long flags;
+
+        check_channel(channel);
+
+        pr_debug("%s: id=%p, data=%08x, size=%d\n",
+                 __FUNCTION__, id, (unsigned int)data, size);
+
+        buf = kmem_cache_alloc(dma_kmem, GFP_ATOMIC);
+        if (buf == NULL) {
+                pr_debug("%s: out of memory (%d alloc)\n",
+                         __FUNCTION__, sizeof(*buf));
+                return -ENOMEM;
+        }
+
+        pr_debug("%s: new buffer %p\n", __FUNCTION__, buf);
+
+        //dbg_showchan(chan);
+
+        buf->next  = NULL;
+        buf->data  = buf->ptr = data;
+        buf->size  = size;
+        buf->id    = id;
+        buf->magic = BUF_MAGIC;
+
+        local_irq_save(flags);
+
+        if (chan->curr == NULL) {
+                /* we've got nothing loaded... */
+                pr_debug("%s: buffer %p queued onto empty channel\n",
+                         __FUNCTION__, buf);
+
+                chan->curr = buf;
+                chan->end  = buf;
+                chan->next = NULL;
+        } else {
+                pr_debug("dma%d: %s: buffer %p queued onto non-empty channel\n",
+                         chan->number, __FUNCTION__, buf);
+
+                if (chan->end == NULL)
+                        pr_debug("dma%d: %s: %p not empty, and chan->end==NULL?\n",
+                                 chan->number, __FUNCTION__, chan);
+
+                chan->end->next = buf;
+                chan->end = buf;
+        }
+
+        /* if necessary, update the next buffer field */
+        if (chan->next == NULL)
+                chan->next = buf;
+
+        /* check to see if we can load a buffer */
+        if (chan->state == S3C2410_DMA_RUNNING) {
+                if (chan->load_state == S3C2410_DMALOAD_1LOADED && 1) {
+                        if (s3c2410_dma_waitforload(chan, __LINE__) == 0) {
+                                printk(KERN_ERR "dma%d: loadbuffer:"
+                                       "timeout loading buffer\n",
+                                       chan->number);
+                                dbg_showchan(chan);
+                                local_irq_restore(flags);
+                                return -EINVAL;
+                        }
+                }
+
+                while (s3c2410_dma_canload(chan) && chan->next != NULL) {
+                        s3c2410_dma_loadbuffer(chan, chan->next);
+                }
+        } else if (chan->state == S3C2410_DMA_IDLE) {
+                if (chan->flags & S3C2410_DMAF_AUTOSTART) {
+                        s3c2410_dma_ctrl(chan->number, S3C2410_DMAOP_START);
+                }
+        }
+
+        local_irq_restore(flags);
+        return 0;
+}
+
+EXPORT_SYMBOL(s3c2410_dma_enqueue);
+
+static inline void
+s3c2410_dma_freebuf(s3c2410_dma_buf_t *buf)
+{
+        int magicok = (buf->magic == BUF_MAGIC);
+
+        buf->magic = -1;
+
+        if (magicok) {
+                kmem_cache_free(dma_kmem, buf);
+        } else {
+                printk("s3c2410_dma_freebuf: buff %p with bad magic\n", buf);
+        }
+}
+
+/* s3c2410_dma_lastxfer
+ *
+ * called when the system is out of buffers, to ensure that the channel
+ * is prepared for shutdown.
+*/
+
+static inline void
+s3c2410_dma_lastxfer(s3c2410_dma_chan_t *chan)
+{
+        pr_debug("dma%d: s3c2410_dma_lastxfer: load_state %d\n",
+                 chan->number, chan->load_state);
+
+        switch (chan->load_state) {
+        case S3C2410_DMALOAD_NONE:
+                break;
+
+        case S3C2410_DMALOAD_1LOADED:
+                if (s3c2410_dma_waitforload(chan, __LINE__) == 0) {
+                                /* flag error? */
+                        printk(KERN_ERR "dma%d: timeout waiting for load\n",
+                               chan->number);
+                        return;
+                }
+                break;
+
+        default:
+                pr_debug("dma%d: lastxfer: unhandled load_state %d with no next",
+                         chan->number, chan->load_state);
+                return;
+
+        }
+
+        /* hopefully this'll shut the damned thing up after the transfer... */
+        dma_wrreg(chan, S3C2410_DMA_DCON, chan->dcon | S3C2410_DCON_NORELOAD);
+}
+
+
+#define dmadbg2(x...)
+
+static irqreturn_t
+s3c2410_dma_irq(int irq, void *devpw, struct pt_regs *regs)
+{
+        s3c2410_dma_chan_t *chan = (s3c2410_dma_chan_t *)devpw;
+        s3c2410_dma_buf_t  *buf;
+
+        buf = chan->curr;
+
+        dbg_showchan(chan);
+
+        /* modify the channel state */
+
+        switch (chan->load_state) {
+        case S3C2410_DMALOAD_1RUNNING:
+                /* TODO - if we are running only one buffer, we probably
+                 * want to reload here, and then worry about the buffer
+                 * callback */
+
+                chan->load_state = S3C2410_DMALOAD_NONE;
+                break;
+
+        case S3C2410_DMALOAD_1LOADED:
+                /* iirc, we should go back to NONE loaded here, we
+                 * had a buffer, and it was never verified as being
+                 * loaded.
+                 */
+
+                chan->load_state = S3C2410_DMALOAD_NONE;
+                break;
+
+        case S3C2410_DMALOAD_1LOADED_1RUNNING:
+                /* we'll worry about checking to see if another buffer is
+                 * ready after we've called back the owner. This should
+                 * ensure we do not wait around too long for the DMA
+                 * engine to start the next transfer
+                 */
+
+                chan->load_state = S3C2410_DMALOAD_1LOADED;
+                break;
+
+        case S3C2410_DMALOAD_NONE:
+                printk(KERN_ERR "dma%d: IRQ with no loaded buffer?\n",
+                       chan->number);
+                break;
+
+        default:
+                printk(KERN_ERR "dma%d: IRQ in invalid load_state %d\n",
+                       chan->number, chan->load_state);
+                break;
+        }
+
+        if (buf != NULL) {
+                /* update the chain to make sure that if we load any more
+                 * buffers when we call the callback function, things should
+                 * work properly */
+
+                chan->curr = buf->next;
+                buf->next  = NULL;
+
+                if (buf->magic != BUF_MAGIC) {
+                        printk(KERN_ERR "dma%d: %s: buf %p incorrect magic\n",
+                               chan->number, __FUNCTION__, buf);
+                        return IRQ_HANDLED;
+                }
+
+                s3c2410_dma_buffdone(chan, buf, S3C2410_RES_OK);
+
+                /* free resouces */
+                s3c2410_dma_freebuf(buf);
+        } else {
+        }
+
+        if (chan->next != NULL) {
+                unsigned long flags;
+
+                switch (chan->load_state) {
+                case S3C2410_DMALOAD_1RUNNING:
+                        /* don't need to do anything for this state */
+                        break;
+
+                case S3C2410_DMALOAD_NONE:
+                        /* can load buffer immediately */
+                        break;
+
+                case S3C2410_DMALOAD_1LOADED:
+                        if (s3c2410_dma_waitforload(chan, __LINE__) == 0) {
+                                /* flag error? */
+                                printk(KERN_ERR "dma%d: timeout waiting for load\n",
+                                       chan->number);
+                                return IRQ_HANDLED;
+                        }
+
+                        break;
+
+                case S3C2410_DMALOAD_1LOADED_1RUNNING:
+                        goto no_load;
+
+                default:
+                        printk(KERN_ERR "dma%d: unknown load_state in irq, %d\n",
+                               chan->number, chan->load_state);
+                        return IRQ_HANDLED;
+                }
+
+                local_irq_save(flags);
+                s3c2410_dma_loadbuffer(chan, chan->next);
+                local_irq_restore(flags);
+        } else {
+                s3c2410_dma_lastxfer(chan);
+
+                /* see if we can stop this channel.. */
+                if (chan->load_state == S3C2410_DMALOAD_NONE) {
+                        pr_debug("dma%d: end of transfer, stopping channel (%ld)\n",
+                                 chan->number, jiffies);
+                        s3c2410_dma_ctrl(chan->number, S3C2410_DMAOP_STOP);
+                }
+        }
+
+ no_load:
+        return IRQ_HANDLED;
+}
+
+
+
+/* s3c2410_request_dma
+ *
+ * get control of an dma channel
+*/
+
+int s3c2410_dma_request(unsigned int channel, s3c2410_dma_client_t *client,
+                        void *dev)
+{
+        s3c2410_dma_chan_t *chan = &s3c2410_chans[channel];
+        unsigned long flags;
+        int err;
+
+        pr_debug("dma%d: s3c2410_request_dma: client=%s, dev=%p\n",
+                 channel, client->name, dev);
+
+        check_channel(channel);
+
+        local_irq_save(flags);
+
+        dbg_showchan(chan);
+
+        if (chan->in_use) {
+                if (client != chan->client) {
+                        printk(KERN_ERR "dma%d: already in use\n", channel);
+                        local_irq_restore(flags);
+                        return -EBUSY;
+                } else {
+                        printk(KERN_ERR "dma%d: client already has channel\n", channel);
+                }
+        }
+
+        chan->client = client;
+        chan->in_use = 1;
+
+        if (!chan->irq_claimed) {
+                pr_debug("dma%d: %s : requesting irq %d\n",
+                         channel, __FUNCTION__, chan->irq);
+
+                err = request_irq(chan->irq, s3c2410_dma_irq, SA_INTERRUPT,
+                                  client->name, (void *)chan);
+
+                if (err) {
+                        chan->in_use = 0;
+                        local_irq_restore(flags);
+
+                        printk(KERN_ERR "%s: cannot get IRQ %d for DMA %d\n",
+                               client->name, chan->irq, chan->number);
+                        return err;
+                }
+
+                chan->irq_claimed = 1;
+                chan->irq_enabled = 1;
+        }
+
+        local_irq_restore(flags);
+
+        /* need to setup */
+
+        pr_debug("%s: channel initialised, %p\n", __FUNCTION__, chan);
+
+        return 0;
+}
+
+EXPORT_SYMBOL(s3c2410_dma_request);
+
+/* s3c2410_dma_free
+ *
+ * release the given channel back to the system, will stop and flush
+ * any outstanding transfers, and ensure the channel is ready for the
+ * next claimant.
+ *
+ * Note, although a warning is currently printed if the freeing client
+ * info is not the same as the registrant's client info, the free is still
+ * allowed to go through.
+*/
+
+int s3c2410_dma_free(dmach_t channel, s3c2410_dma_client_t *client)
+{
+        s3c2410_dma_chan_t *chan = &s3c2410_chans[channel];
+        unsigned long flags;
+
+        check_channel(channel);
+
+        local_irq_save(flags);
+
+
+        if (chan->client != client) {
+                printk(KERN_WARNING "dma%d: possible free from different client (channel %p, passed %p)\n",
+                       channel, chan->client, client);
+        }
+
+        /* sort out stopping and freeing the channel */
+
+        if (chan->state != S3C2410_DMA_IDLE) {
+                pr_debug("%s: need to stop dma channel %p\n",
+                       __FUNCTION__, chan);
+
+                /* possibly flush the channel */
+                s3c2410_dma_ctrl(channel, S3C2410_DMAOP_STOP);
+        }
+
+        chan->client = NULL;
+        chan->in_use = 0;
+
+        local_irq_restore(flags);
+
+        return 0;
+}
+
+EXPORT_SYMBOL(s3c2410_dma_free);
+
+static int s3c2410_dma_dostop(s3c2410_dma_chan_t *chan)
+{
+        unsigned long tmp;
+        unsigned long flags;
+
+        pr_debug("%s:\n", __FUNCTION__);
+
+        dbg_showchan(chan);
+
+        local_irq_save(flags);
+
+        s3c2410_dma_call_op(chan,  S3C2410_DMAOP_STOP);
+
+        tmp = dma_rdreg(chan, S3C2410_DMA_DMASKTRIG);
+        tmp |= S3C2410_DMASKTRIG_STOP;
+        dma_wrreg(chan, S3C2410_DMA_DMASKTRIG, tmp);
+
+#if 0
+        /* should also clear interrupts, according to WinCE BSP */
+        tmp = dma_rdreg(chan, S3C2410_DMA_DCON);
+        tmp |= S3C2410_DCON_NORELOAD;
+        dma_wrreg(chan, S3C2410_DMA_DCON, tmp);
+#endif
+
+        chan->state      = S3C2410_DMA_IDLE;
+        chan->load_state = S3C2410_DMALOAD_NONE;
+
+        local_irq_restore(flags);
+
+        return 0;
+}
+
+/* s3c2410_dma_flush
+ *
+ * stop the channel, and remove all current and pending transfers
+*/
+
+static int s3c2410_dma_flush(s3c2410_dma_chan_t *chan)
+{
+        s3c2410_dma_buf_t *buf, *next;
+        unsigned long flags;
+
+        pr_debug("%s:\n", __FUNCTION__);
+
+        local_irq_save(flags);
+
+        if (chan->state != S3C2410_DMA_IDLE) {
+                pr_debug("%s: stopping channel...\n", __FUNCTION__ );
+                s3c2410_dma_ctrl(chan->number, S3C2410_DMAOP_STOP);
+        }
+
+        buf = chan->curr;
+        if (buf == NULL)
+                buf = chan->next;
+
+        chan->curr = chan->next = chan->end = NULL;
+
+        if (buf != NULL) {
+                for ( ; buf != NULL; buf = next) {
+                        next = buf->next;
+
+                        pr_debug("%s: free buffer %p, next %p\n",
+                               __FUNCTION__, buf, buf->next);
+
+                        s3c2410_dma_buffdone(chan, buf, S3C2410_RES_ABORT);
+                        s3c2410_dma_freebuf(buf);
+                }
+        }
+
+        local_irq_restore(flags);
+
+        return 0;
+}
+
+
+int
+s3c2410_dma_ctrl(dmach_t channel, s3c2410_chan_op_t op)
+{
+        s3c2410_dma_chan_t *chan = &s3c2410_chans[channel];
+
+        check_channel(channel);
+
+        switch (op) {
+        case S3C2410_DMAOP_START:
+                return s3c2410_dma_start(chan);
+
+        case S3C2410_DMAOP_STOP:
+                return s3c2410_dma_dostop(chan);
+
+        case S3C2410_DMAOP_PAUSE:
+                return -ENOENT;
+
+        case S3C2410_DMAOP_RESUME:
+                return -ENOENT;
+
+        case S3C2410_DMAOP_FLUSH:
+                return s3c2410_dma_flush(chan);
+
+        case S3C2410_DMAOP_TIMEOUT:
+                return 0;
+
+        }
+
+        return -ENOENT;      /* unknown, don't bother */
+}
+
+EXPORT_SYMBOL(s3c2410_dma_ctrl);
+
+/* DMA configuration for each channel
+ *
+ * DISRCC -> source of the DMA (AHB,APB)
+ * DISRC  -> source address of the DMA
+ * DIDSTC -> destination of the DMA (AHB,APD)
+ * DIDST  -> destination address of the DMA
+*/
+
+/* s3c2410_dma_config
+ *
+ * xfersize:     size of unit in bytes (1,2,4)
+ * dcon:         base value of the DCONx register
+*/
+
+int s3c2410_dma_config(dmach_t channel,
+                       int xferunit,
+                       int dcon)
+{
+        s3c2410_dma_chan_t *chan = &s3c2410_chans[channel];
+
+        pr_debug("%s: chan=%d, xfer_unit=%d, dcon=%08x\n",
+                 __FUNCTION__, channel, xferunit, dcon);
+
+        check_channel(channel);
+
+        switch (xferunit) {
+        case 1:
+                dcon |= S3C2410_DCON_BYTE;
+                break;
+
+        case 2:
+                dcon |= S3C2410_DCON_HALFWORD;
+                break;
+
+        case 4:
+                dcon |= S3C2410_DCON_WORD;
+                break;
+
+        default:
+                pr_debug("%s: bad transfer size %d\n", __FUNCTION__, xferunit);
+                return -EINVAL;
+        }
+
+        dcon |= S3C2410_DCON_HWTRIG;
+        dcon |= S3C2410_DCON_INTREQ;
+
+        pr_debug("%s: dcon now %08x\n", __FUNCTION__, dcon);
+
+        chan->dcon = dcon;
+        chan->xfer_unit = xferunit;
+
+        return 0;
+}
+
+EXPORT_SYMBOL(s3c2410_dma_config);
+
+int s3c2410_dma_setflags(dmach_t channel, unsigned int flags)
+{
+        s3c2410_dma_chan_t *chan = &s3c2410_chans[channel];
+
+        check_channel(channel);
+
+        pr_debug("%s: chan=%p, flags=%08x\n", __FUNCTION__, chan, flags);
+
+        chan->flags = flags;
+
+        return 0;
+}
+
+EXPORT_SYMBOL(s3c2410_dma_setflags);
+
+
+/* do we need to protect the settings of the fields from
+ * irq?
+*/
+
+int s3c2410_dma_set_opfn(dmach_t channel, s3c2410_dma_opfn_t rtn)
+{
+        s3c2410_dma_chan_t *chan = &s3c2410_chans[channel];
+
+        check_channel(channel);
+
+        pr_debug("%s: chan=%p, op rtn=%p\n", __FUNCTION__, chan, rtn);
+
+        chan->op_fn = rtn;
+
+        return 0;
+}
+
+EXPORT_SYMBOL(s3c2410_dma_set_opfn);
+
+int s3c2410_dma_set_buffdone_fn(dmach_t channel, s3c2410_dma_cbfn_t rtn)
+{
+        s3c2410_dma_chan_t *chan = &s3c2410_chans[channel];
+
+        check_channel(channel);
+
+        pr_debug("%s: chan=%p, callback rtn=%p\n", __FUNCTION__, chan, rtn);
+
+        chan->callback_fn = rtn;
+
+        return 0;
+}
+
+EXPORT_SYMBOL(s3c2410_dma_set_buffdone_fn);
+
+/* s3c2410_dma_devconfig
+ *
+ * configure the dma source/destination hardware type and address
+ *
+ * source:    S3C2410_DMASRC_HW: source is hardware
+ *            S3C2410_DMASRC_MEM: source is memory
+ *
+ * hwcfg:     the value for xxxSTCn register,
+ *            bit 0: 0=increment pointer, 1=leave pointer
+ *            bit 1: 0=soucre is AHB, 1=soucre is APB
+ *
+ * devaddr:   physical address of the source
+*/
+
+int s3c2410_dma_devconfig(int channel,
+                          s3c2410_dmasrc_t source,
+                          int hwcfg,
+                          unsigned long devaddr)
+{
+        s3c2410_dma_chan_t *chan = &s3c2410_chans[channel];
+
+        check_channel(channel);
+
+        pr_debug("%s: source=%d, hwcfg=%08x, devaddr=%08lx\n",
+                 __FUNCTION__, (int)source, hwcfg, devaddr);
+
+        chan->source = source;
+        chan->dev_addr = devaddr;
+
+        switch (source) {
+        case S3C2410_DMASRC_HW:
+                /* source is hardware */
+                pr_debug("%s: hw source, devaddr=%08lx, hwcfg=%d\n",
+                         __FUNCTION__, devaddr, hwcfg);
+                dma_wrreg(chan, S3C2410_DMA_DISRCC, hwcfg & 3);
+                dma_wrreg(chan, S3C2410_DMA_DISRC,  devaddr);
+                dma_wrreg(chan, S3C2410_DMA_DIDSTC, (0<<1) | (0<<0));
+
+                chan->addr_reg = dma_regaddr(chan, S3C2410_DMA_DIDST);
+                return 0;
+
+        case S3C2410_DMASRC_MEM:
+                /* source is memory */
+                pr_debug( "%s: mem source, devaddr=%08lx, hwcfg=%d\n",
+                          __FUNCTION__, devaddr, hwcfg);
+                dma_wrreg(chan, S3C2410_DMA_DISRCC, (0<<1) | (0<<0));
+                dma_wrreg(chan, S3C2410_DMA_DIDST,  devaddr);
+                dma_wrreg(chan, S3C2410_DMA_DIDSTC, hwcfg & 3);
+
+                chan->addr_reg = dma_regaddr(chan, S3C2410_DMA_DISRC);
+                return 0;
+        }
+
+        printk(KERN_ERR "dma%d: invalid source type (%d)\n", channel, source);
+        return -EINVAL;
+}
+
+EXPORT_SYMBOL(s3c2410_dma_devconfig);
+
+/* s3c2410_dma_getposition
+ *
+ * returns the current transfer points for the dma source and destination
+*/
+
+int s3c2410_dma_getposition(dmach_t channel, dma_addr_t *src, dma_addr_t *dst)
+{
+        s3c2410_dma_chan_t *chan = &s3c2410_chans[channel];
+
+        check_channel(channel);
+
+        if (src != NULL)
+                *src = dma_rdreg(chan, S3C2410_DMA_DCSRC);
+
+        if (dst != NULL)
+                *dst = dma_rdreg(chan, S3C2410_DMA_DCDST);
+
+        return 0;
+}
+
+EXPORT_SYMBOL(s3c2410_dma_getposition);
+
+
+/* system device class */
+
+#ifdef CONFIG_PM
+
+static int s3c2410_dma_suspend(struct sys_device *dev, pm_message_t state)
+{
+        s3c2410_dma_chan_t *cp = container_of(dev, s3c2410_dma_chan_t, dev);
+
+        printk(KERN_DEBUG "suspending dma channel %d\n", cp->number);
+
+        if (dma_rdreg(cp, S3C2410_DMA_DMASKTRIG) & S3C2410_DMASKTRIG_ON) {
+                /* the dma channel is still working, which is probably
+                 * a bad thing to do over suspend/resume. We stop the
+                 * channel and assume that the client is either going to
+                 * retry after resume, or that it is broken.
+                 */
+
+                printk(KERN_INFO "dma: stopping channel %d due to suspend\n",
+                       cp->number);
+
+                s3c2410_dma_dostop(cp);
+        }
+
+        return 0;
+}
+
+static int s3c2410_dma_resume(struct sys_device *dev)
+{
+        return 0;
+}
+
+#else
+#define s3c2410_dma_suspend NULL
+#define s3c2410_dma_resume  NULL
+#endif /* CONFIG_PM */
+
+static struct sysdev_class dma_sysclass = {
+        set_kset_name("s3c24xx-dma"),
+        .suspend        = s3c2410_dma_suspend,
+        .resume         = s3c2410_dma_resume,
+};
+
+/* kmem cache implementation */
+
+static void s3c2410_dma_cache_ctor(void *p, kmem_cache_t *c, unsigned long f)
+{
+        memset(p, 0, sizeof(s3c2410_dma_buf_t));
+}
+
+
+/* initialisation code */
+
+static int __init s3c2410_init_dma(void)
+{
+        s3c2410_dma_chan_t *cp;
+        int channel;
+        int ret;
+
+        printk("S3C2410 DMA Driver, (c) 2003-2004 Simtec Electronics\n");
+
+        dma_base = ioremap(S3C2410_PA_DMA, 0x200);
+        if (dma_base == NULL) {
+                printk(KERN_ERR "dma failed to remap register block\n");
+                return -ENOMEM;
+        }
+
+        ret = sysdev_class_register(&dma_sysclass);
+        if (ret != 0) {
+                printk(KERN_ERR "dma sysclass registration failed\n");
+                goto err;
+        }
+
+        dma_kmem = kmem_cache_create("dma_desc", sizeof(s3c2410_dma_buf_t), 0,
+                                     SLAB_HWCACHE_ALIGN,
+                                     s3c2410_dma_cache_ctor, NULL);
+
+        if (dma_kmem == NULL) {
+                printk(KERN_ERR "dma failed to make kmem cache\n");
+                ret = -ENOMEM;
+                goto err;
+        }
+
+        for (channel = 0; channel < S3C2410_DMA_CHANNELS; channel++) {
+                cp = &s3c2410_chans[channel];
+
+                memset(cp, 0, sizeof(s3c2410_dma_chan_t));
+
+                /* dma channel irqs are in order.. */
+                cp->number = channel;
+                cp->irq    = channel + IRQ_DMA0;
+                cp->regs   = dma_base + (channel*0x40);
+
+                /* point current stats somewhere */
+                cp->stats  = &cp->stats_store;
+                cp->stats_store.timeout_shortest = LONG_MAX;
+
+                /* basic channel configuration */
+
+                cp->load_timeout = 1<<18;
+
+                /* register system device */
+
+                cp->dev.cls = &dma_sysclass;
+                cp->dev.id  = channel;
+                ret = sysdev_register(&cp->dev);
+
+                printk("DMA channel %d at %p, irq %d\n",
+                       cp->number, cp->regs, cp->irq);
+        }
+
+        return 0;
+
+ err:
+        kmem_cache_destroy(dma_kmem);
+        iounmap(dma_base);
+        dma_base = NULL;
+        return ret;
+}
+
+__initcall(s3c2410_init_dma);