summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorRussell King <rmk+kernel@arm.linux.org.uk>2014-04-25 12:58:29 +0100
committerChris Ball <chris@printf.net>2014-05-22 07:26:29 -0400
commitde0b65a786ae83c8f6dfb712f65b9a36af70a981 (patch)
tree5e806a20e51bafdb7a42e209239b98ab0620ceb6
parent0718e59ae259f7c48155b4e852d8b0632d59028e (diff)
mmc: sdhci: avoid sync'ing the SG if there's no misalignment
On read, we don't need to sync the whole scatterlist and then check whether any segments need copying - if we check first, we avoid potentially expensive cache handling. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Tested-by: Markus Pargmann <mpa@pengutronix.de> Tested-by: Stephen Warren <swarren@nvidia.com> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Chris Ball <chris@printf.net>
-rw-r--r--drivers/mmc/host/sdhci.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 074157e8e73d..4f878bcfaa2d 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -602,6 +602,7 @@ static void sdhci_adma_table_post(struct sdhci_host *host,
u8 *align;
char *buffer;
unsigned long flags;
+ bool has_unaligned;
if (data->flags & MMC_DATA_READ)
direction = DMA_FROM_DEVICE;
@@ -614,7 +615,15 @@ static void sdhci_adma_table_post(struct sdhci_host *host,
dma_unmap_single(mmc_dev(host->mmc), host->align_addr,
128 * 4, direction);
- if (data->flags & MMC_DATA_READ) {
+ /* Do a quick scan of the SG list for any unaligned mappings */
+ has_unaligned = false;
+ for_each_sg(data->sg, sg, host->sg_count, i)
+ if (sg_dma_address(sg) & 3) {
+ has_unaligned = true;
+ break;
+ }
+
+ if (has_unaligned && data->flags & MMC_DATA_READ) {
dma_sync_sg_for_cpu(mmc_dev(host->mmc), data->sg,
data->sg_len, direction);