[ARM] 3753/1: S3C24XX: DMA fixes

Patch from Ben Dooks

A number of small issues with the S3C24XX DMA have
cropped up, which this patch fixes. These are:

  - check wether we can load another buff in start
  - update state handling in s3c2410_dma_lastxfer
  - only reload in irq if channel is not idle
  - more informative timeout errors (add source)
  - do not call request_irq() with irqs locked
  - added waitforstop function

The patch also adds a S3C2410_DMAOP_STARTED for
the occasions when the driver wants to ensure that
the DMA system load state is resynced after loading.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

2 files changed, 145 insertions, 19 deletions

diff --git a/arch/arm/mach-s3c2410/dma.c b/arch/arm/mach-s3c2410/dma.c
index 094cc52745c5..25855452fe8c 100644
--- a/arch/arm/mach-s3c2410/dma.c
+++ b/arch/arm/mach-s3c2410/dma.c
@@ -112,7 +112,7 @@ dmadbg_capture(s3c2410_dma_chan_t *chan, struct s3c2410_dma_regstate *regs)
 }
 
 static void
-dmadbg_showregs(const char *fname, int line, s3c2410_dma_chan_t *chan,
+dmadbg_dumpregs(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",
@@ -132,7 +132,16 @@ dmadbg_showchan(const char *fname, int line, s3c2410_dma_chan_t *chan)
                chan->number, fname, line, chan->load_state,
                chan->curr, chan->next, chan->end);
 
-        dmadbg_showregs(fname, line, chan, &state);
+        dmadbg_dumpregs(fname, line, chan, &state);
+}
+
+static void
+dmadbg_showregs(const char *fname, int line, s3c2410_dma_chan_t *chan)
+{
+        struct s3c2410_dma_regstate state;
+
+        dmadbg_capture(chan, &state);
+        dmadbg_dumpregs(fname, line, chan, &state);
 }
 
 #define dbg_showregs(chan) dmadbg_showregs(__FUNCTION__, __LINE__, (chan))
@@ -253,10 +262,14 @@ s3c2410_dma_loadbuffer(s3c2410_dma_chan_t *chan,
                          buf->next);
                 reload = (buf->next == NULL) ? S3C2410_DCON_NORELOAD : 0;
         } else {
-                pr_debug("load_state is %d => autoreload\n", chan->load_state);
+                //pr_debug("load_state is %d => autoreload\n", chan->load_state);
                 reload = S3C2410_DCON_AUTORELOAD;
         }
 
+        if ((buf->data & 0xf0000000) != 0x30000000) {
+                dmawarn("dmaload: buffer is %p\n", (void *)buf->data);
+        }
+
         writel(buf->data, chan->addr_reg);
 
         dma_wrreg(chan, S3C2410_DMA_DCON,
@@ -370,7 +383,7 @@ static int s3c2410_dma_start(s3c2410_dma_chan_t *chan)
         tmp |= S3C2410_DMASKTRIG_ON;
         dma_wrreg(chan, S3C2410_DMA_DMASKTRIG, tmp);
 
-        pr_debug("wrote %08lx to DMASKTRIG\n", tmp);
+        pr_debug("dma%d: %08lx to DMASKTRIG\n", chan->number, tmp);
 
 #if 0
         /* the dma buffer loads should take care of clearing the AUTO
@@ -384,7 +397,30 @@ static int s3c2410_dma_start(s3c2410_dma_chan_t *chan)
 
         dbg_showchan(chan);
 
+        /* if we've only loaded one buffer onto the channel, then chec
+         * to see if we have another, and if so, try and load it so when
+         * the first buffer is finished, the new one will be loaded onto
+         * the channel */
+
+        if (chan->next != NULL) {
+                if (chan->load_state == S3C2410_DMALOAD_1LOADED) {
+
+                        if (s3c2410_dma_waitforload(chan, __LINE__) == 0) {
+                                pr_debug("%s: buff not yet loaded, no more todo\n",
+                                         __FUNCTION__);
+                        } else {
+                                chan->load_state = S3C2410_DMALOAD_1RUNNING;
+                                s3c2410_dma_loadbuffer(chan, chan->next);
+                        }
+
+                } else if (chan->load_state == S3C2410_DMALOAD_1RUNNING) {
+                        s3c2410_dma_loadbuffer(chan, chan->next);
+                }
+        }
+
+
         local_irq_restore(flags);
+
         return 0;
 }
 
@@ -436,12 +472,11 @@ int s3c2410_dma_enqueue(unsigned int channel, void *id,
         buf = kmem_cache_alloc(dma_kmem, GFP_ATOMIC);
         if (buf == NULL) {
                 pr_debug("%s: out of memory (%ld alloc)\n",
-                         __FUNCTION__, sizeof(*buf));
+                         __FUNCTION__, (long)sizeof(*buf));
                 return -ENOMEM;
         }
 
-        pr_debug("%s: new buffer %p\n", __FUNCTION__, buf);
-
+        //pr_debug("%s: new buffer %p\n", __FUNCTION__, buf);
         //dbg_showchan(chan);
 
         buf->next  = NULL;
@@ -537,14 +572,20 @@ s3c2410_dma_lastxfer(s3c2410_dma_chan_t *chan)
         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);
+                        printk(KERN_ERR "dma%d: timeout waiting for load (%s)\n",
+                               chan->number, __FUNCTION__);
                         return;
                 }
                 break;
 
+        case S3C2410_DMALOAD_1LOADED_1RUNNING:
+                /* I belive in this case we do not have anything to do
+                 * until the next buffer comes along, and we turn off the
+                 * reload */
+                return;
+
         default:
-                pr_debug("dma%d: lastxfer: unhandled load_state %d with no next",
+                pr_debug("dma%d: lastxfer: unhandled load_state %d with no next\n",
                          chan->number, chan->load_state);
                 return;
 
@@ -629,7 +670,14 @@ s3c2410_dma_irq(int irq, void *devpw, struct pt_regs *regs)
         } else {
         }
 
-        if (chan->next != NULL) {
+        /* only reload if the channel is still running... our buffer done
+         * routine may have altered the state by requesting the dma channel
+         * to stop or shutdown... */
+
+        /* todo: check that when the channel is shut-down from inside this
+         * function, we cope with unsetting reload, etc */
+
+        if (chan->next != NULL && chan->state != S3C2410_DMA_IDLE) {
                 unsigned long flags;
 
                 switch (chan->load_state) {
@@ -644,8 +692,8 @@ s3c2410_dma_irq(int irq, void *devpw, struct pt_regs *regs)
                 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);
+                                printk(KERN_ERR "dma%d: timeout waiting for load (%s)\n",
+                                       chan->number, __FUNCTION__);
                                 return IRQ_HANDLED;
                         }
 
@@ -678,8 +726,6 @@ s3c2410_dma_irq(int irq, void *devpw, struct pt_regs *regs)
         return IRQ_HANDLED;
 }
 
-
-
 /* s3c2410_request_dma
  *
  * get control of an dma channel
@@ -718,11 +764,17 @@ int s3c2410_dma_request(unsigned int channel, s3c2410_dma_client_t *client,
                 pr_debug("dma%d: %s : requesting irq %d\n",
                          channel, __FUNCTION__, chan->irq);
 
+                chan->irq_claimed = 1;
+                local_irq_restore(flags);
+
                 err = request_irq(chan->irq, s3c2410_dma_irq, IRQF_DISABLED,
                                   client->name, (void *)chan);
 
+                local_irq_save(flags);
+
                 if (err) {
                         chan->in_use = 0;
+                        chan->irq_claimed = 0;
                         local_irq_restore(flags);
 
                         printk(KERN_ERR "%s: cannot get IRQ %d for DMA %d\n",
@@ -730,7 +782,6 @@ int s3c2410_dma_request(unsigned int channel, s3c2410_dma_client_t *client,
                         return err;
                 }
 
-                chan->irq_claimed = 1;
                 chan->irq_enabled = 1;
         }
 
@@ -810,6 +861,7 @@ static int s3c2410_dma_dostop(s3c2410_dma_chan_t *chan)
 
         tmp = dma_rdreg(chan, S3C2410_DMA_DMASKTRIG);
         tmp |= S3C2410_DMASKTRIG_STOP;
+        //tmp &= ~S3C2410_DMASKTRIG_ON;
         dma_wrreg(chan, S3C2410_DMA_DMASKTRIG, tmp);
 
 #if 0
@@ -819,6 +871,7 @@ static int s3c2410_dma_dostop(s3c2410_dma_chan_t *chan)
         dma_wrreg(chan, S3C2410_DMA_DCON, tmp);
 #endif
 
+        /* should stop do this, or should we wait for flush? */
         chan->state      = S3C2410_DMA_IDLE;
         chan->load_state = S3C2410_DMALOAD_NONE;
 
@@ -827,6 +880,22 @@ static int s3c2410_dma_dostop(s3c2410_dma_chan_t *chan)
         return 0;
 }
 
+void s3c2410_dma_waitforstop(s3c2410_dma_chan_t *chan)
+{
+        unsigned long tmp;
+        unsigned int timeout = 0x10000;
+
+        while (timeout-- > 0) {
+                tmp = dma_rdreg(chan, S3C2410_DMA_DMASKTRIG);
+
+                if (!(tmp & S3C2410_DMASKTRIG_ON))
+                        return;
+        }
+
+        pr_debug("dma%d: failed to stop?\n", chan->number);
+}
+
+
 /* s3c2410_dma_flush
  *
  * stop the channel, and remove all current and pending transfers
@@ -837,7 +906,9 @@ static int s3c2410_dma_flush(s3c2410_dma_chan_t *chan)
         s3c2410_dma_buf_t *buf, *next;
         unsigned long flags;
 
-        pr_debug("%s:\n", __FUNCTION__);
+        pr_debug("%s: chan %p (%d)\n", __FUNCTION__, chan, chan->number);
+
+        dbg_showchan(chan);
 
         local_irq_save(flags);
 
@@ -864,11 +935,64 @@ static int s3c2410_dma_flush(s3c2410_dma_chan_t *chan)
                 }
         }
 
+        dbg_showregs(chan);
+
+        s3c2410_dma_waitforstop(chan);
+
+#if 0
+        /* should also clear interrupts, according to WinCE BSP */
+        {
+                unsigned long tmp;
+
+                tmp = dma_rdreg(chan, S3C2410_DMA_DCON);
+                tmp |= S3C2410_DCON_NORELOAD;
+                dma_wrreg(chan, S3C2410_DMA_DCON, tmp);
+        }
+#endif
+
+        dbg_showregs(chan);
+
         local_irq_restore(flags);
 
         return 0;
 }
 
+int
+s3c2410_dma_started(s3c2410_dma_chan_t *chan)
+{
+        unsigned long flags;
+
+        local_irq_save(flags);
+
+        dbg_showchan(chan);
+
+        /* if we've only loaded one buffer onto the channel, then chec
+         * to see if we have another, and if so, try and load it so when
+         * the first buffer is finished, the new one will be loaded onto
+         * the channel */
+
+        if (chan->next != NULL) {
+                if (chan->load_state == S3C2410_DMALOAD_1LOADED) {
+
+                        if (s3c2410_dma_waitforload(chan, __LINE__) == 0) {
+                                pr_debug("%s: buff not yet loaded, no more todo\n",
+                                         __FUNCTION__);
+                        } else {
+                                chan->load_state = S3C2410_DMALOAD_1RUNNING;
+                                s3c2410_dma_loadbuffer(chan, chan->next);
+                        }
+
+                } else if (chan->load_state == S3C2410_DMALOAD_1RUNNING) {
+                        s3c2410_dma_loadbuffer(chan, chan->next);
+                }
+        }
+
+
+        local_irq_restore(flags);
+
+        return 0;
+
+}
 
 int
 s3c2410_dma_ctrl(dmach_t channel, s3c2410_chan_op_t op)
@@ -885,14 +1009,15 @@ s3c2410_dma_ctrl(dmach_t channel, s3c2410_chan_op_t op)
                 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_STARTED:
+                return s3c2410_dma_started(chan);
+
         case S3C2410_DMAOP_TIMEOUT:
                 return 0;
 
diff --git a/include/asm-arm/arch-s3c2410/dma.h b/include/asm-arm/arch-s3c2410/dma.h
index 72964f9b8414..7463fd5252ce 100644
--- a/include/asm-arm/arch-s3c2410/dma.h
+++ b/include/asm-arm/arch-s3c2410/dma.h
@@ -104,6 +104,7 @@ enum s3c2410_chan_op_e {
         S3C2410_DMAOP_RESUME,
         S3C2410_DMAOP_FLUSH,
         S3C2410_DMAOP_TIMEOUT,           /* internal signal to handler */
+        S3C2410_DMAOP_STARTED,          /* indicate channel started */
 };
 
 typedef enum s3c2410_chan_op_e s3c2410_chan_op_t;