These cards show abysmal write performance when
writes < 12K that are 8K unaligned cross an 8K barrier.
Change-Id: I3b015a93ae21d077b447e7d6fbe81255dbd2b0df
Signed-off-by: Andrei Warkentin <andreiw@xxxxxxxxxxxx>
---
drivers/mmc/card/Kconfig | 9 +++++++++
drivers/mmc/card/block.c | 20 ++++++++++++++++++++
2 files changed, 29 insertions(+), 0 deletions(-)
diff --git a/drivers/mmc/card/Kconfig b/drivers/mmc/card/Kconfig
index 86948f9..1a9e4aa 100644
--- a/drivers/mmc/card/Kconfig
+++ b/drivers/mmc/card/Kconfig
@@ -14,6 +14,15 @@ config MMC_BLOCK
mount the filesystem. Almost everyone wishing MMC support
should say Y or M here.
+config MMC_BLOCK_QUIRK_TOSHIBA_32NM
+ tristate "Toshiba MMC 32nm technology flash device quirks"
+ depends on MMC_BLOCK
+ default n
+ help
+ Say Y if you have a Toshiba 32nm technology flash device,
+ such as MMC32G or MMC16G eMMCs. This enables a performance
+ improvement for flash page unaligned writes.
+
config MMC_BLOCK_BOUNCE
bool "Use bounce buffer for simple hosts"
depends on MMC_BLOCK
diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index a8f18c7..5250748 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -729,8 +729,28 @@ mmc_blk_set_blksize(struct mmc_blk_data *md, struct mmc_card *card)
return 0;
}
+#ifdef CONFIG_MMC_BLOCK_QUIRK_TOSHIBA_32NM
+static void toshiba_32nm_fixup(struct mmc_card *card, int data)
+{
+ struct mmc_blk_data *md = mmc_get_drvdata(card);
+ printk(KERN_INFO "Applying Toshiba 32nm workarounds\n");
+
+ /* Page size 8K, this card doesn't like unaligned writes
+ across 8K boundary. */
+ md->write_align_size = 8192;
+
+ /* Doing the alignment for accesses > 12K seems to
+ result in decreased perf. */
+ md->write_align_limit = 12288;
+}
+#endif /* CONFIG_MMC_BLOCK_QUIRK_TOSHIBA_32NM */
+
static const struct mmc_fixup blk_fixups[] =
{
+#ifdef CONFIG_MMC_BLOCK_QUIRK_TOSHIBA_32NM
+ MMC_FIXUP("MMC16G", 0x11, 0x0, toshiba_32nm_fixup, 0),
+ MMC_FIXUP("MMC32G", 0x11, 0x0100, toshiba_32nm_fixup, 0),
+#endif /* CONFIG_MMC_BLOCK_QUIRK_TOSHIBA_32NM */
END_FIXUP
};
--
1.7.0.4
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