diff options
| author | Russell King <rmk+kernel@arm.linux.org.uk> | 2014-04-25 12:58:29 +0100 |
|---|---|---|
| committer | Chris Ball <chris@printf.net> | 2014-05-22 07:26:29 -0400 |
| commit | de0b65a786ae83c8f6dfb712f65b9a36af70a981 (patch) | |
| tree | 5e806a20e51bafdb7a42e209239b98ab0620ceb6 /drivers/mmc/host | |
| parent | 0718e59ae259f7c48155b4e852d8b0632d59028e (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>
Diffstat (limited to 'drivers/mmc/host')
| -rw-r--r-- | drivers/mmc/host/sdhci.c | 11 |
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); |