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Commit fa4e9989 authored by Russell King's avatar Russell King Committed by Russell King
Browse files

[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: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 308d333a

arch/arm/mach-rpc/dma.c

+9 −5
Original line number Original line Diff line number Diff line
@@ -32,6 +32,8 @@ struct iomd_dma { 
	unsigned long		base;		/* Controller base address */

	unsigned long		base;		/* Controller base address */

	int			irq;		/* Controller IRQ */

	int			irq;		/* Controller IRQ */

	struct scatterlist	cur_sg;		/* Current controller buffer */

	struct scatterlist	cur_sg;		/* Current controller buffer */

	dma_addr_t		dma_addr;

	unsigned int		dma_len;

};

};





#if 0

#if 0
@@ -57,10 +59,10 @@ static void iomd_get_next_sg(struct scatterlist *sg, struct iomd_dma *idma) 
	unsigned long end, offset, flags = 0;

	unsigned long end, offset, flags = 0;





	if (idma->dma.sg) {

	if (idma->dma.sg) {

		sg->dma_address = idma->dma.sg->dma_address;

		sg->dma_address = idma->dma_addr;

		offset = sg->dma_address & ~PAGE_MASK;

		offset = sg->dma_address & ~PAGE_MASK;





		end = offset + idma->dma.sg->length;

		end = offset + idma->dma_len;





		if (end > PAGE_SIZE)

		if (end > PAGE_SIZE)

			end = PAGE_SIZE;

			end = PAGE_SIZE;
@@ -70,12 +72,14 @@ static void iomd_get_next_sg(struct scatterlist *sg, struct iomd_dma *idma) 




		sg->length = end - TRANSFER_SIZE;

		sg->length = end - TRANSFER_SIZE;





		idma->dma.sg->length -= end - offset;

		idma->dma_len -= end - offset;

		idma->dma.sg->dma_address += end - offset;

		idma->dma_addr += end - offset;





		if (idma->dma.sg->length == 0) {

		if (idma->dma_len == 0) {

			if (idma->dma.sgcount > 1) {

			if (idma->dma.sgcount > 1) {

				idma->dma.sg = sg_next(idma->dma.sg);

				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--;

				idma->dma.sgcount--;

			} else {

			} else {

				idma->dma.sg = NULL;

				idma->dma.sg = NULL;