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Commit 55c25c2f authored by Jayachandran C's avatar Jayachandran C Committed by Ralf Baechle
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MIPS: mm: Move some checks out of 'for' loop in DMA operations 



The check cpu_needs_post_dma_flush() in mips_dma_sync_sg_for_cpu() and
the check !plat_device_is_coherent() in mips_dma_sync_sg_for_device()
can be moved outside the for loop.

As a side effect, this also avoids a GCC bug that caused kernel compile
to fail with the error:

arch/mips/mm/dma-default.c: In function 'mips_dma_sync_sg_for_cpu':
arch/mips/mm/dma-default.c:316:1: internal compiler error: in add_insn_before, at emit-rtl.c:3852

This gcc failure is seen in Code Sourcery toolchains [e.g. gcc version
4.7.2 (Sourcery CodeBench Lite 2012.09-99)] after commit "MIPS: Optimize
current_cpu_type() for better code."

Signed-off-by: default avatarJayachandran C <jchandra@broadcom.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5907/


Reviewed-by: default avatarMarkos Chandras <markos.chandras@imgtec.com>
Tested-by: default avatarMarkos Chandras <markos.chandras@imgtec.com>
Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent becee6b8

arch/mips/mm/dma-default.c

+4 −8
Original line number Original line Diff line number Diff line
@@ -308,26 +308,22 @@ static void mips_dma_sync_sg_for_cpu(struct device *dev, 
{

{

	int i;

	int i;





	/* Make sure that gcc doesn't leave the empty loop body.  */

	for (i = 0; i < nelems; i++, sg++) {

	if (cpu_needs_post_dma_flush(dev))

	if (cpu_needs_post_dma_flush(dev))

		for (i = 0; i < nelems; i++, sg++)

			__dma_sync(sg_page(sg), sg->offset, sg->length,

			__dma_sync(sg_page(sg), sg->offset, sg->length,

				   direction);

				   direction);

}

}

}





static void mips_dma_sync_sg_for_device(struct device *dev,

static void mips_dma_sync_sg_for_device(struct device *dev,

	struct scatterlist *sg, int nelems, enum dma_data_direction direction)

	struct scatterlist *sg, int nelems, enum dma_data_direction direction)

{

{

	int i;

	int i;





	/* Make sure that gcc doesn't leave the empty loop body.  */

	for (i = 0; i < nelems; i++, sg++) {

	if (!plat_device_is_coherent(dev))

	if (!plat_device_is_coherent(dev))

		for (i = 0; i < nelems; i++, sg++)

			__dma_sync(sg_page(sg), sg->offset, sg->length,

			__dma_sync(sg_page(sg), sg->offset, sg->length,

				   direction);

				   direction);

}

}

}





int mips_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)

int mips_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)

{

{