[ARM] dma: RiscPC: don't modify DMA SG entries
We should not be modifying the scatterlist passed to us from the
driver code; doing so breaks assumptions made by the DMA API code,
and could cause problems if the driver retries a transfer using an
old scatterlist.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mach-rpc/dma.c b/arch/arm/mach-rpc/dma.c
index 1f77cdc..c47d974 100644
--- a/arch/arm/mach-rpc/dma.c
+++ b/arch/arm/mach-rpc/dma.c
@@ -32,6 +32,8 @@
unsigned long base; /* Controller base address */
int irq; /* Controller IRQ */
struct scatterlist cur_sg; /* Current controller buffer */
+ dma_addr_t dma_addr;
+ unsigned int dma_len;
};
#if 0
@@ -57,10 +59,10 @@
unsigned long end, offset, flags = 0;
if (idma->dma.sg) {
- sg->dma_address = idma->dma.sg->dma_address;
+ sg->dma_address = idma->dma_addr;
offset = sg->dma_address & ~PAGE_MASK;
- end = offset + idma->dma.sg->length;
+ end = offset + idma->dma_len;
if (end > PAGE_SIZE)
end = PAGE_SIZE;
@@ -70,12 +72,14 @@
sg->length = end - TRANSFER_SIZE;
- idma->dma.sg->length -= end - offset;
- idma->dma.sg->dma_address += end - offset;
+ idma->dma_len -= end - offset;
+ idma->dma_addr += end - offset;
- if (idma->dma.sg->length == 0) {
+ if (idma->dma_len == 0) {
if (idma->dma.sgcount > 1) {
idma->dma.sg = sg_next(idma->dma.sg);
+ idma->dma_addr = idma->dma.sg->dma_address;
+ idma->dma_len = idma->dma.sg->length;
idma->dma.sgcount--;
} else {
idma->dma.sg = NULL;