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>

2 files changed, 12 insertions, 0 deletions

diff --git a/arch/arm/mach-s3c2410/include/mach/dma.h b/arch/arm/mach-s3c2410/include/mach/dma.h
index c3a2629e0ded..92e2687009ea 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 1067619f0ba0..004edab23954 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 */