From: "Wolfgang Mües" <wolfgang.mues@auerswald.de>
To: Pierre Ossman <drzeus@drzeus.cx>
Cc: "Andrew Morton" <akpm@linux-foundation.org>,
"Matt Fleming" <matt@console-pimps.org>,
"David Brownell" <dbrownell@users.sourceforge.net>,
"Mike Frysinger" <vapier.adi@gmail.com>,
linux-kernel@vger.kernel.org
Subject: [PATCH] mmc_spi: speedup for slow cards, less wear-out
Date: Wed, 8 Apr 2009 10:14:07 +0100 [thread overview]
Message-ID: <200904081114.07653.wolfgang.mues@auerswald.de> (raw)
From: Wolfgang Muees <wolfgang.mues@auerswald.de>
o Speedup for slow cards by transfering more data at once.
This patch also reduces the amount of wear-out of the flash
blocks because fewer partial blocks are written.
Signed-off-by: Wolfgang Muees <wolfgang.mues@auerswald.de>
---
diff -uprN 2_6_29_rc7_patch1253467/drivers/mmc/host/mmc_spi.c 2_6_29_rc7_patch_wearout_speedup/drivers/mmc/host/mmc_spi.c
--- 2_6_29_rc7_patch1253467/drivers/mmc/host/mmc_spi.c 2009-04-07 17:19:21.000000000 +0200
+++ 2_6_29_rc7_patch_wearout_speedup/drivers/mmc/host/mmc_spi.c 2009-04-08 11:11:20.000000000 +0200
@@ -97,6 +97,14 @@
*/
#define r1b_timeout (HZ * 3)
+/* One of the critical speed parameters is the amount of data which may
+ * be transfered in one command. If this value is too low, the SD card
+ * controller has to do multiple partial block writes (argggh!). With
+ * today (2008) SD cards there is little speed gain if we transfer more
+ * than 64 KBytes at a time. So use this value until there is any indication
+ * that we should do more here.
+ */
+#define MMC_SPI_BLOCKSATONCE 128
/****************************************************************************/
@@ -1366,6 +1374,10 @@ static int mmc_spi_probe(struct spi_devi
mmc->ops = &mmc_spi_ops;
mmc->max_blk_size = MMC_SPI_BLOCKSIZE;
+ mmc->max_hw_segs = MMC_SPI_BLOCKSATONCE;
+ mmc->max_phys_segs = MMC_SPI_BLOCKSATONCE;
+ mmc->max_req_size = MMC_SPI_BLOCKSATONCE * MMC_SPI_BLOCKSIZE;
+ mmc->max_blk_count = MMC_SPI_BLOCKSATONCE;
mmc->caps = MMC_CAP_SPI;
---
regards
i. A. Wolfgang Mües
--
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next reply other threads:[~2009-04-08 9:14 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-08 9:14 Wolfgang Mües [this message]
2009-04-10 22:04 ` Pierre Ossman
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