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authorBen Dooks <ben-linux@fluff.org>2009-09-22 16:48:56 +0100
committerBen Dooks <ben-linux@fluff.org>2009-10-28 18:22:57 +0000
commite3d8024891dbfec6cf36c9b76177650f48118462 (patch)
tree2046fa2ec4259e32b02ef29107fa6ace142e8f8f
parent964fe080d94db82a3268443e9b9ece4c60246414 (diff)
downloadop-kernel-dev-e3d8024891dbfec6cf36c9b76177650f48118462.zip
op-kernel-dev-e3d8024891dbfec6cf36c9b76177650f48118462.tar.gz
ARM: S3C: Add info for supporting circular DMA buffers
The S3C64XX DMA implementation will work a lot better with the ability to enqueue circular buffers as the hardware can do it's own linked-list management. Add a function s3c_dma_has_circular() to show that the system can do this and a flag for the channel. Update the s3c24xx/s3c64xx I2S DMA code to deal with this. Signed-off-by: Ben Dooks <ben@simtec.co.uk> Signed-off-by: Ben Dooks <ben-linux@fluff.org> Acked-by: Mark Brown <broonie@@opensource.wolfsonmicro.com>
-rw-r--r--arch/arm/mach-s3c2410/include/mach/dma.h7
-rw-r--r--arch/arm/mach-s3c6400/include/mach/dma.h5
-rw-r--r--sound/soc/s3c24xx/s3c24xx-pcm.c17
3 files changed, 27 insertions, 2 deletions
diff --git a/arch/arm/mach-s3c2410/include/mach/dma.h b/arch/arm/mach-s3c2410/include/mach/dma.h
index c3a2629..92e2687 100644
--- a/arch/arm/mach-s3c2410/include/mach/dma.h
+++ b/arch/arm/mach-s3c2410/include/mach/dma.h
@@ -110,6 +110,8 @@ enum s3c2410_dma_loadst {
* waiting for reloads */
#define S3C2410_DMAF_AUTOSTART (1<<1) /* auto-start if buffer queued */
+#define S3C2410_DMAF_CIRCULAR (1 << 2) /* no circular dma support */
+
/* dma buffer */
struct s3c2410_dma_buf;
@@ -194,4 +196,9 @@ struct s3c2410_dma_chan {
typedef unsigned long dma_device_t;
+static inline bool s3c_dma_has_circular(void)
+{
+ return false;
+}
+
#endif /* __ASM_ARCH_DMA_H */
diff --git a/arch/arm/mach-s3c6400/include/mach/dma.h b/arch/arm/mach-s3c6400/include/mach/dma.h
index 1067619..004edab 100644
--- a/arch/arm/mach-s3c6400/include/mach/dma.h
+++ b/arch/arm/mach-s3c6400/include/mach/dma.h
@@ -68,6 +68,11 @@ static __inline__ int s3c_dma_has_circular(void)
#define S3C2410_DMAF_CIRCULAR (1 << 0)
+static inline bool s3c_dma_has_circular(void)
+{
+ return false;
+}
+
#include <plat/dma.h>
#endif /* __ASM_ARCH_IRQ_H */
diff --git a/sound/soc/s3c24xx/s3c24xx-pcm.c b/sound/soc/s3c24xx/s3c24xx-pcm.c
index 5cbbdc8..1f35c6f 100644
--- a/sound/soc/s3c24xx/s3c24xx-pcm.c
+++ b/sound/soc/s3c24xx/s3c24xx-pcm.c
@@ -75,11 +75,19 @@ static void s3c24xx_pcm_enqueue(struct snd_pcm_substream *substream)
{
struct s3c24xx_runtime_data *prtd = substream->runtime->private_data;
dma_addr_t pos = prtd->dma_pos;
+ unsigned int limit;
int ret;
pr_debug("Entered %s\n", __func__);
- while (prtd->dma_loaded < prtd->dma_limit) {
+ if (s3c_dma_has_circular()) {
+ limit = (prtd->dma_end - prtd->dma_start) / prtd->dma_period;
+ } else
+ limit = prtd->dma_limit;
+
+ pr_debug("%s: loaded %d, limit %d\n", __func__, prtd->dma_loaded, limit);
+
+ while (prtd->dma_loaded < limit) {
unsigned long len = prtd->dma_period;
pr_debug("dma_loaded: %d\n", prtd->dma_loaded);
@@ -123,7 +131,7 @@ static void s3c24xx_audio_buffdone(struct s3c2410_dma_chan *channel,
snd_pcm_period_elapsed(substream);
spin_lock(&prtd->lock);
- if (prtd->state & ST_RUNNING) {
+ if (prtd->state & ST_RUNNING && !s3c_dma_has_circular()) {
prtd->dma_loaded--;
s3c24xx_pcm_enqueue(substream);
}
@@ -164,6 +172,11 @@ static int s3c24xx_pcm_hw_params(struct snd_pcm_substream *substream,
printk(KERN_ERR "failed to get dma channel\n");
return ret;
}
+
+ /* use the circular buffering if we have it available. */
+ if (s3c_dma_has_circular())
+ s3c2410_dma_setflags(prtd->params->channel,
+ S3C2410_DMAF_CIRCULAR);
}
s3c2410_dma_set_buffdone_fn(prtd->params->channel,
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