Merge branch 'upstream-linus' of master.kernel.org:/pub/scm/linux/kernel/git/jgarzik...
[sfrench/cifs-2.6.git] / arch / arm / mach-s3c2410 / dma.c
index 25855452fe8ce7029cbc4b726a77868e18bb4b23..717322a0916bd4f9a9f5831a11db6d6cb3fecc83 100644 (file)
@@ -1,35 +1,16 @@
-/* linux/arch/arm/mach-bast/dma.c
+/* linux/arch/arm/mach-s3c2410/dma.c
  *
- * (c) 2003-2005 Simtec Electronics
+ * Copyright (c) 2003-2005,2006 Simtec Electronics
  *     Ben Dooks <ben@simtec.co.uk>
  *
  * S3C2410 DMA core
  *
- * http://www.simtec.co.uk/products/EB2410ITX/
+ * http://armlinux.simtec.co.uk/
  *
  * 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
- */
+*/
 
 
 #ifdef CONFIG_S3C2410_DMA_DEBUG
 #include <asm/mach/dma.h>
 #include <asm/arch/map.h>
 
+#include "dma.h"
+
 /* io map for dma */
 static void __iomem *dma_base;
-static kmem_cache_t *dma_kmem;
+static struct kmem_cache *dma_kmem;
+
+struct s3c24xx_dma_selection dma_sel;
 
 /* dma channel state information */
-s3c2410_dma_chan_t s3c2410_chans[S3C2410_DMA_CHANNELS];
+struct s3c2410_dma_chan s3c2410_chans[S3C2410_DMA_CHANNELS];
 
 /* debugging functions */
 
@@ -74,12 +59,11 @@ s3c2410_dma_chan_t s3c2410_chans[S3C2410_DMA_CHANNELS];
 #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)
+dma_wrreg(struct s3c2410_dma_chan *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))
@@ -102,7 +86,7 @@ struct s3c2410_dma_regstate {
 */
 
 static void
-dmadbg_capture(s3c2410_dma_chan_t *chan, struct s3c2410_dma_regstate *regs)
+dmadbg_capture(struct s3c2410_dma_chan *chan, struct s3c2410_dma_regstate *regs)
 {
        regs->dcsrc    = dma_rdreg(chan, S3C2410_DMA_DCSRC);
        regs->disrc    = dma_rdreg(chan, S3C2410_DMA_DISRC);
@@ -112,7 +96,7 @@ dmadbg_capture(s3c2410_dma_chan_t *chan, struct s3c2410_dma_regstate *regs)
 }
 
 static void
-dmadbg_dumpregs(const char *fname, int line, s3c2410_dma_chan_t *chan,
+dmadbg_dumpregs(const char *fname, int line, struct s3c2410_dma_chan *chan,
                 struct s3c2410_dma_regstate *regs)
 {
        printk(KERN_DEBUG "dma%d: %s:%d: DCSRC=%08lx, DISRC=%08lx, DSTAT=%08lx DMT=%02lx, DCON=%08lx\n",
@@ -122,7 +106,7 @@ dmadbg_dumpregs(const char *fname, int line, s3c2410_dma_chan_t *chan,
 }
 
 static void
-dmadbg_showchan(const char *fname, int line, s3c2410_dma_chan_t *chan)
+dmadbg_showchan(const char *fname, int line, struct s3c2410_dma_chan *chan)
 {
        struct s3c2410_dma_regstate state;
 
@@ -136,7 +120,7 @@ dmadbg_showchan(const char *fname, int line, s3c2410_dma_chan_t *chan)
 }
 
 static void
-dmadbg_showregs(const char *fname, int line, s3c2410_dma_chan_t *chan)
+dmadbg_showregs(const char *fname, int line, struct s3c2410_dma_chan *chan)
 {
        struct s3c2410_dma_regstate state;
 
@@ -151,12 +135,20 @@ dmadbg_showregs(const char *fname, int line, s3c2410_dma_chan_t *chan)
 #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)
+static struct s3c2410_dma_chan *dma_chan_map[DMACH_MAX];
 
+/* lookup_dma_channel
+ *
+ * change the dma channel number given into a real dma channel id
+*/
+
+static struct s3c2410_dma_chan *lookup_dma_channel(unsigned int channel)
+{
+       if (channel & DMACH_LOW_LEVEL)
+               return &s3c2410_chans[channel & ~DMACH_LOW_LEVEL];
+       else
+               return dma_chan_map[channel];
+}
 
 /* s3c2410_dma_stats_timeout
  *
@@ -164,7 +156,7 @@ dmadbg_showregs(const char *fname, int line, s3c2410_dma_chan_t *chan)
 */
 
 static void
-s3c2410_dma_stats_timeout(s3c2410_dma_stats_t *stats, int val)
+s3c2410_dma_stats_timeout(struct s3c2410_dma_stats *stats, int val)
 {
        if (stats == NULL)
                return;
@@ -183,7 +175,7 @@ s3c2410_dma_stats_timeout(s3c2410_dma_stats_t *stats, int val)
 */
 
 static int
-s3c2410_dma_waitforload(s3c2410_dma_chan_t *chan, int line)
+s3c2410_dma_waitforload(struct s3c2410_dma_chan *chan, int line)
 {
        int timeout = chan->load_timeout;
        int took;
@@ -230,8 +222,8 @@ s3c2410_dma_waitforload(s3c2410_dma_chan_t *chan, int line)
 */
 
 static inline int
-s3c2410_dma_loadbuffer(s3c2410_dma_chan_t *chan,
-                      s3c2410_dma_buf_t *buf)
+s3c2410_dma_loadbuffer(struct s3c2410_dma_chan *chan,
+                      struct s3c2410_dma_buf *buf)
 {
        unsigned long reload;
 
@@ -304,7 +296,7 @@ s3c2410_dma_loadbuffer(s3c2410_dma_chan_t *chan,
 */
 
 static void
-s3c2410_dma_call_op(s3c2410_dma_chan_t *chan, s3c2410_chan_op_t op)
+s3c2410_dma_call_op(struct s3c2410_dma_chan *chan, enum s3c2410_chan_op op)
 {
        if (chan->op_fn != NULL) {
                (chan->op_fn)(chan, op);
@@ -318,11 +310,13 @@ s3c2410_dma_call_op(s3c2410_dma_chan_t *chan, s3c2410_chan_op_t op)
 */
 
 static inline void
-s3c2410_dma_buffdone(s3c2410_dma_chan_t *chan, s3c2410_dma_buf_t *buf,
-                    s3c2410_dma_buffresult_t result)
+s3c2410_dma_buffdone(struct s3c2410_dma_chan *chan, struct s3c2410_dma_buf *buf,
+                    enum s3c2410_dma_buffresult result)
 {
+#if 0
        pr_debug("callback_fn=%p, buf=%p, id=%p, size=%d, result=%d\n",
                 chan->callback_fn, buf, buf->id, buf->size, result);
+#endif
 
        if (chan->callback_fn != NULL) {
                (chan->callback_fn)(chan, buf->id, buf->size, result);
@@ -334,7 +328,7 @@ s3c2410_dma_buffdone(s3c2410_dma_chan_t *chan, s3c2410_dma_buf_t *buf,
  * start a dma channel going
 */
 
-static int s3c2410_dma_start(s3c2410_dma_chan_t *chan)
+static int s3c2410_dma_start(struct s3c2410_dma_chan *chan)
 {
        unsigned long tmp;
        unsigned long flags;
@@ -430,7 +424,7 @@ static int s3c2410_dma_start(s3c2410_dma_chan_t *chan)
 */
 
 static int
-s3c2410_dma_canload(s3c2410_dma_chan_t *chan)
+s3c2410_dma_canload(struct s3c2410_dma_chan *chan)
 {
        if (chan->load_state == S3C2410_DMALOAD_NONE ||
            chan->load_state == S3C2410_DMALOAD_1RUNNING)
@@ -439,7 +433,6 @@ s3c2410_dma_canload(s3c2410_dma_chan_t *chan)
        return 0;
 }
 
-
 /* s3c2410_dma_enqueue
  *
  * queue an given buffer for dma transfer.
@@ -460,11 +453,12 @@ s3c2410_dma_canload(s3c2410_dma_chan_t *chan)
 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;
+       struct s3c2410_dma_chan *chan = lookup_dma_channel(channel);
+       struct s3c2410_dma_buf *buf;
        unsigned long flags;
 
-       check_channel(channel);
+       if (chan == NULL)
+               return -EINVAL;
 
        pr_debug("%s: id=%p, data=%08x, size=%d\n",
                 __FUNCTION__, id, (unsigned int)data, size);
@@ -540,7 +534,7 @@ int s3c2410_dma_enqueue(unsigned int channel, void *id,
 EXPORT_SYMBOL(s3c2410_dma_enqueue);
 
 static inline void
-s3c2410_dma_freebuf(s3c2410_dma_buf_t *buf)
+s3c2410_dma_freebuf(struct s3c2410_dma_buf *buf)
 {
        int magicok = (buf->magic == BUF_MAGIC);
 
@@ -560,10 +554,12 @@ s3c2410_dma_freebuf(s3c2410_dma_buf_t *buf)
 */
 
 static inline void
-s3c2410_dma_lastxfer(s3c2410_dma_chan_t *chan)
+s3c2410_dma_lastxfer(struct s3c2410_dma_chan *chan)
 {
+#if 0
        pr_debug("dma%d: s3c2410_dma_lastxfer: load_state %d\n",
                 chan->number, chan->load_state);
+#endif
 
        switch (chan->load_state) {
        case S3C2410_DMALOAD_NONE:
@@ -599,10 +595,10 @@ s3c2410_dma_lastxfer(s3c2410_dma_chan_t *chan)
 #define dmadbg2(x...)
 
 static irqreturn_t
-s3c2410_dma_irq(int irq, void *devpw, struct pt_regs *regs)
+s3c2410_dma_irq(int irq, void *devpw)
 {
-       s3c2410_dma_chan_t *chan = (s3c2410_dma_chan_t *)devpw;
-       s3c2410_dma_buf_t  *buf;
+       struct s3c2410_dma_chan *chan = (struct s3c2410_dma_chan *)devpw;
+       struct s3c2410_dma_buf  *buf;
 
        buf = chan->curr;
 
@@ -718,7 +714,8 @@ s3c2410_dma_irq(int irq, void *devpw, struct pt_regs *regs)
                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);
+                       s3c2410_dma_ctrl(chan->number | DMACH_LOW_LEVEL,
+                                        S3C2410_DMAOP_STOP);
                }
        }
 
@@ -726,37 +723,34 @@ s3c2410_dma_irq(int irq, void *devpw, struct pt_regs *regs)
        return IRQ_HANDLED;
 }
 
+static struct s3c2410_dma_chan *s3c2410_dma_map_channel(int channel);
+
 /* s3c2410_request_dma
  *
  * get control of an dma channel
 */
 
-int s3c2410_dma_request(unsigned int channel, s3c2410_dma_client_t *client,
+int s3c2410_dma_request(unsigned int channel,
+                       struct s3c2410_dma_client *client,
                        void *dev)
 {
-       s3c2410_dma_chan_t *chan = &s3c2410_chans[channel];
+       struct s3c2410_dma_chan *chan;
        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 = s3c2410_dma_map_channel(channel);
+       if (chan == NULL) {
+               local_irq_restore(flags);
+               return -EBUSY;
        }
 
+       dbg_showchan(chan);
+
        chan->client = client;
        chan->in_use = 1;
 
@@ -807,16 +801,16 @@ EXPORT_SYMBOL(s3c2410_dma_request);
  * allowed to go through.
 */
 
-int s3c2410_dma_free(dmach_t channel, s3c2410_dma_client_t *client)
+int s3c2410_dma_free(dmach_t channel, struct s3c2410_dma_client *client)
 {
-       s3c2410_dma_chan_t *chan = &s3c2410_chans[channel];
+       struct s3c2410_dma_chan *chan = lookup_dma_channel(channel);
        unsigned long flags;
 
-       check_channel(channel);
+       if (chan == NULL)
+               return -EINVAL;
 
        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);
@@ -837,8 +831,12 @@ int s3c2410_dma_free(dmach_t channel, s3c2410_dma_client_t *client)
 
        if (chan->irq_claimed)
                free_irq(chan->irq, (void *)chan);
+
        chan->irq_claimed = 0;
 
+       if (!(channel & DMACH_LOW_LEVEL))
+               dma_chan_map[channel] = NULL;
+
        local_irq_restore(flags);
 
        return 0;
@@ -846,10 +844,10 @@ int s3c2410_dma_free(dmach_t channel, s3c2410_dma_client_t *client)
 
 EXPORT_SYMBOL(s3c2410_dma_free);
 
-static int s3c2410_dma_dostop(s3c2410_dma_chan_t *chan)
+static int s3c2410_dma_dostop(struct s3c2410_dma_chan *chan)
 {
-       unsigned long tmp;
        unsigned long flags;
+       unsigned long tmp;
 
        pr_debug("%s:\n", __FUNCTION__);
 
@@ -880,7 +878,7 @@ static int s3c2410_dma_dostop(s3c2410_dma_chan_t *chan)
        return 0;
 }
 
-void s3c2410_dma_waitforstop(s3c2410_dma_chan_t *chan)
+void s3c2410_dma_waitforstop(struct s3c2410_dma_chan *chan)
 {
        unsigned long tmp;
        unsigned int timeout = 0x10000;
@@ -901,9 +899,9 @@ void s3c2410_dma_waitforstop(s3c2410_dma_chan_t *chan)
  * stop the channel, and remove all current and pending transfers
 */
 
-static int s3c2410_dma_flush(s3c2410_dma_chan_t *chan)
+static int s3c2410_dma_flush(struct s3c2410_dma_chan *chan)
 {
-       s3c2410_dma_buf_t *buf, *next;
+       struct s3c2410_dma_buf *buf, *next;
        unsigned long flags;
 
        pr_debug("%s: chan %p (%d)\n", __FUNCTION__, chan, chan->number);
@@ -958,7 +956,7 @@ static int s3c2410_dma_flush(s3c2410_dma_chan_t *chan)
 }
 
 int
-s3c2410_dma_started(s3c2410_dma_chan_t *chan)
+s3c2410_dma_started(struct s3c2410_dma_chan *chan)
 {
        unsigned long flags;
 
@@ -995,11 +993,12 @@ s3c2410_dma_started(s3c2410_dma_chan_t *chan)
 }
 
 int
-s3c2410_dma_ctrl(dmach_t channel, s3c2410_chan_op_t op)
+s3c2410_dma_ctrl(dmach_t channel, enum s3c2410_chan_op op)
 {
-       s3c2410_dma_chan_t *chan = &s3c2410_chans[channel];
+       struct s3c2410_dma_chan *chan = lookup_dma_channel(channel);
 
-       check_channel(channel);
+       if (chan == NULL)
+               return -EINVAL;
 
        switch (op) {
        case S3C2410_DMAOP_START:
@@ -1046,12 +1045,19 @@ int s3c2410_dma_config(dmach_t channel,
                       int xferunit,
                       int dcon)
 {
-       s3c2410_dma_chan_t *chan = &s3c2410_chans[channel];
+       struct s3c2410_dma_chan *chan = lookup_dma_channel(channel);
 
        pr_debug("%s: chan=%d, xfer_unit=%d, dcon=%08x\n",
                 __FUNCTION__, channel, xferunit, dcon);
 
-       check_channel(channel);
+       if (chan == NULL)
+               return -EINVAL;
+
+       printk("Initial dcon is %08x\n", dcon);
+
+       dcon |= chan->dcon & dma_sel.dcon_mask;
+
+       printk("New dcon is %08x\n", dcon);
 
        switch (xferunit) {
        case 1:
@@ -1086,9 +1092,10 @@ EXPORT_SYMBOL(s3c2410_dma_config);
 
 int s3c2410_dma_setflags(dmach_t channel, unsigned int flags)
 {
-       s3c2410_dma_chan_t *chan = &s3c2410_chans[channel];
+       struct s3c2410_dma_chan *chan = lookup_dma_channel(channel);
 
-       check_channel(channel);
+       if (chan == NULL)
+               return -EINVAL;
 
        pr_debug("%s: chan=%p, flags=%08x\n", __FUNCTION__, chan, flags);
 
@@ -1106,9 +1113,10 @@ EXPORT_SYMBOL(s3c2410_dma_setflags);
 
 int s3c2410_dma_set_opfn(dmach_t channel, s3c2410_dma_opfn_t rtn)
 {
-       s3c2410_dma_chan_t *chan = &s3c2410_chans[channel];
+       struct s3c2410_dma_chan *chan = lookup_dma_channel(channel);
 
-       check_channel(channel);
+       if (chan == NULL)
+               return -EINVAL;
 
        pr_debug("%s: chan=%p, op rtn=%p\n", __FUNCTION__, chan, rtn);
 
@@ -1121,9 +1129,10 @@ 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];
+       struct s3c2410_dma_chan *chan = lookup_dma_channel(channel);
 
-       check_channel(channel);
+       if (chan == NULL)
+               return -EINVAL;
 
        pr_debug("%s: chan=%p, callback rtn=%p\n", __FUNCTION__, chan, rtn);
 
@@ -1149,13 +1158,14 @@ EXPORT_SYMBOL(s3c2410_dma_set_buffdone_fn);
 */
 
 int s3c2410_dma_devconfig(int channel,
-                         s3c2410_dmasrc_t source,
+                         enum s3c2410_dmasrc source,
                          int hwcfg,
                          unsigned long devaddr)
 {
-       s3c2410_dma_chan_t *chan = &s3c2410_chans[channel];
+       struct s3c2410_dma_chan *chan = lookup_dma_channel(channel);
 
-       check_channel(channel);
+       if (chan == NULL)
+               return -EINVAL;
 
        pr_debug("%s: source=%d, hwcfg=%08x, devaddr=%08lx\n",
                 __FUNCTION__, (int)source, hwcfg, devaddr);
@@ -1200,9 +1210,10 @@ EXPORT_SYMBOL(s3c2410_dma_devconfig);
 
 int s3c2410_dma_getposition(dmach_t channel, dma_addr_t *src, dma_addr_t *dst)
 {
-       s3c2410_dma_chan_t *chan = &s3c2410_chans[channel];
+       struct s3c2410_dma_chan *chan = lookup_dma_channel(channel);
 
-       check_channel(channel);
+       if (chan == NULL)
+               return -EINVAL;
 
        if (src != NULL)
                *src = dma_rdreg(chan, S3C2410_DMA_DCSRC);
@@ -1222,7 +1233,7 @@ EXPORT_SYMBOL(s3c2410_dma_getposition);
 
 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);
+       struct s3c2410_dma_chan *cp = container_of(dev, struct s3c2410_dma_chan, dev);
 
        printk(KERN_DEBUG "suspending dma channel %d\n", cp->number);
 
@@ -1252,7 +1263,7 @@ static int s3c2410_dma_resume(struct sys_device *dev)
 #define s3c2410_dma_resume  NULL
 #endif /* CONFIG_PM */
 
-static struct sysdev_class dma_sysclass = {
+struct sysdev_class dma_sysclass = {
        set_kset_name("s3c24xx-dma"),
        .suspend        = s3c2410_dma_suspend,
        .resume         = s3c2410_dma_resume,
@@ -1260,21 +1271,20 @@ static struct sysdev_class dma_sysclass = {
 
 /* kmem cache implementation */
 
-static void s3c2410_dma_cache_ctor(void *p, kmem_cache_t *c, unsigned long f)
+static void s3c2410_dma_cache_ctor(void *p, struct kmem_cache *c, unsigned long f)
 {
-       memset(p, 0, sizeof(s3c2410_dma_buf_t));
+       memset(p, 0, sizeof(struct s3c2410_dma_buf));
 }
 
-
 /* initialisation code */
 
 static int __init s3c2410_init_dma(void)
 {
-       s3c2410_dma_chan_t *cp;
+       struct s3c2410_dma_chan *cp;
        int channel;
        int ret;
 
-       printk("S3C2410 DMA Driver, (c) 2003-2004 Simtec Electronics\n");
+       printk("S3C24XX DMA Driver, (c) 2003-2004,2006 Simtec Electronics\n");
 
        dma_base = ioremap(S3C24XX_PA_DMA, 0x200);
        if (dma_base == NULL) {
@@ -1282,13 +1292,15 @@ static int __init s3c2410_init_dma(void)
                return -ENOMEM;
        }
 
+       printk("Registering sysclass\n");
+
        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,
+       dma_kmem = kmem_cache_create("dma_desc", sizeof(struct s3c2410_dma_buf), 0,
                                     SLAB_HWCACHE_ALIGN,
                                     s3c2410_dma_cache_ctor, NULL);
 
@@ -1301,7 +1313,7 @@ static int __init s3c2410_init_dma(void)
        for (channel = 0; channel < S3C2410_DMA_CHANNELS; channel++) {
                cp = &s3c2410_chans[channel];
 
-               memset(cp, 0, sizeof(s3c2410_dma_chan_t));
+               memset(cp, 0, sizeof(struct s3c2410_dma_chan));
 
                /* dma channel irqs are in order.. */
                cp->number = channel;
@@ -1335,4 +1347,95 @@ static int __init s3c2410_init_dma(void)
        return ret;
 }
 
-__initcall(s3c2410_init_dma);
+core_initcall(s3c2410_init_dma);
+
+static inline int is_channel_valid(unsigned int channel)
+{
+       return (channel & DMA_CH_VALID);
+}
+
+/* s3c2410_dma_map_channel()
+ *
+ * turn the virtual channel number into a real, and un-used hardware
+ * channel.
+ *
+ * currently this code uses first-free channel from the specified harware
+ * map, not taking into account anything that the board setup code may
+ * have to say about the likely peripheral set to be in use.
+*/
+
+struct s3c2410_dma_chan *s3c2410_dma_map_channel(int channel)
+{
+       struct s3c24xx_dma_map *ch_map;
+       struct s3c2410_dma_chan *dmach;
+       int ch;
+
+       if (dma_sel.map == NULL || channel > dma_sel.map_size)
+               return NULL;
+
+       ch_map = dma_sel.map + channel;
+
+       for (ch = 0; ch < S3C2410_DMA_CHANNELS; ch++) {
+               if (!is_channel_valid(ch_map->channels[ch]))
+                       continue;
+
+               if (s3c2410_chans[ch].in_use == 0) {
+                       printk("mapped channel %d to %d\n", channel, ch);
+                       break;
+               }
+       }
+
+       if (ch >= S3C2410_DMA_CHANNELS)
+               return NULL;
+
+       /* update our channel mapping */
+
+       dmach = &s3c2410_chans[ch];
+       dma_chan_map[channel] = dmach;
+
+       /* select the channel */
+
+       (dma_sel.select)(dmach, ch_map);
+
+       return dmach;
+}
+
+static void s3c24xx_dma_show_ch(struct s3c24xx_dma_map *map, int ch)
+{
+       /* show the channel configuration */
+
+       printk("%2d: %20s, channels %c%c%c%c\n", ch, map->name,
+              (is_channel_valid(map->channels[0]) ? '0' : '-'),
+              (is_channel_valid(map->channels[1]) ? '1' : '-'),
+              (is_channel_valid(map->channels[2]) ? '2' : '-'),
+              (is_channel_valid(map->channels[3]) ? '3' : '-'));
+}
+
+static int s3c24xx_dma_check_entry(struct s3c24xx_dma_map *map, int ch)
+{
+       if (1)
+               s3c24xx_dma_show_ch(map, ch);
+
+       return 0;
+}
+
+int __init s3c24xx_dma_init_map(struct s3c24xx_dma_selection *sel)
+{
+       struct s3c24xx_dma_map *nmap;
+       size_t map_sz = sizeof(*nmap) * sel->map_size;
+       int ptr;
+
+       nmap = kmalloc(map_sz, GFP_KERNEL);
+       if (nmap == NULL)
+               return -ENOMEM;
+
+       memcpy(nmap, sel->map, map_sz);
+       memcpy(&dma_sel, sel, sizeof(*sel));
+
+       dma_sel.map = nmap;
+
+       for (ptr = 0; ptr < sel->map_size; ptr++)
+               s3c24xx_dma_check_entry(nmap+ptr, ptr);
+
+       return 0;
+}