Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 47fa9613 authored by Russell King's avatar Russell King Committed by Ulf Hansson
Browse files

mmc: sdhci: avoid walking SG list for writes 



If we are writing data to the card, there is no point in walking the
scatterlist to find out if there are any unaligned entries; this is a
needless waste of CPU cycles.  Avoid this by checking for a non-read
tranfer first.

Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Tested-by: default avatarGregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent acc3ad13

drivers/mmc/host/sdhci.c

+22 −20
Original line number Diff line number Diff line
@@ -559,22 +559,23 @@ static void sdhci_adma_table_post(struct sdhci_host *host, 
	void *align;

	char *buffer;

	unsigned long flags;

	bool has_unaligned;



	if (data->flags & MMC_DATA_READ)

		direction = DMA_FROM_DEVICE;

	else

		direction = DMA_TO_DEVICE;



	if (data->flags & MMC_DATA_READ) {

		bool has_unaligned = false;



		/* 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) & SDHCI_ADMA2_MASK) {

				has_unaligned = true;

				break;

			}



	if (has_unaligned && data->flags & MMC_DATA_READ) {

		if (has_unaligned) {

			dma_sync_sg_for_cpu(mmc_dev(host->mmc), data->sg,

				data->sg_len, direction);
@@ -593,6 +594,7 @@ static void sdhci_adma_table_post(struct sdhci_host *host, 
				}

			}

		}

	}



	if (data->host_cookie == COOKIE_MAPPED) {

		dma_unmap_sg(mmc_dev(host->mmc), data->sg,