On Wed, Sep 25, 2013 at 06:31:05PM +0530, Jayachandran C wrote:
The patch was missing the required Signed-off-by, added below.
> 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: Jayachandran C <jchandra@xxxxxxxxxxxx>
> ---
> arch/mips/mm/dma-default.c | 12 ++++--------
> 1 file changed, 4 insertions(+), 8 deletions(-)
>
> diff --git a/arch/mips/mm/dma-default.c b/arch/mips/mm/dma-default.c
> index e45e4b0..2e94185 100644
> --- a/arch/mips/mm/dma-default.c
> +++ b/arch/mips/mm/dma-default.c
> @@ -307,12 +307,10 @@ static void mips_dma_sync_sg_for_cpu(struct device *dev,
> {
> 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,
> direction);
> - }
> }
>
> static void mips_dma_sync_sg_for_device(struct device *dev,
> @@ -320,12 +318,10 @@ static void mips_dma_sync_sg_for_device(struct device *dev,
> {
> 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,
> direction);
> - }
> }
>
> int mips_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
JC.
