ARM: S3C64XX: DMA: Protect buffer pointers while manipulation

Ensure the DMA buffer points are not updated from
another source during the process of enquing a buffer.

Signed-off-by: Jassi Brar <jassi.brar@samsung.com>
[ben-linux@fluff.org: Updated patch comment]
Signed-off-by: Ben Dooks <ben-linux@fluff.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/arch/arm/plat-s3c64xx/dma.c b/arch/arm/plat-s3c64xx/dma.c
index 266a10745a85..6fa706f0f42a 100644
--- a/arch/arm/plat-s3c64xx/dma.c
+++ b/arch/arm/plat-s3c64xx/dma.c
@@ -339,6 +339,7 @@ int s3c2410_dma_enqueue(unsigned int channel, void *id,
         struct s3c64xx_dma_buff *next;
         struct s3c64xx_dma_buff *buff;
         struct pl080s_lli *lli;
+        unsigned long flags;
         int ret;
 
         WARN_ON(!chan);
@@ -366,6 +367,8 @@ int s3c2410_dma_enqueue(unsigned int channel, void *id,
 
         s3c64xx_dma_fill_lli(chan, lli, data, size);
 
+        local_irq_save(flags);
+
         if ((next = chan->next) != NULL) {
                 struct s3c64xx_dma_buff *end = chan->end;
                 struct pl080s_lli *endlli = end->lli;
@@ -397,6 +400,8 @@ int s3c2410_dma_enqueue(unsigned int channel, void *id,
                 s3c64xx_lli_to_regs(chan, lli);
         }
 
+        local_irq_restore(flags);
+
         show_lli(lli);
 
         dbg_showchan(chan);