diff options
Diffstat (limited to 'target/linux/ep93xx/patches-2.6.39/002-mmc_spi_fix_sdhc.patch')
| -rw-r--r-- | target/linux/ep93xx/patches-2.6.39/002-mmc_spi_fix_sdhc.patch | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/target/linux/ep93xx/patches-2.6.39/002-mmc_spi_fix_sdhc.patch b/target/linux/ep93xx/patches-2.6.39/002-mmc_spi_fix_sdhc.patch new file mode 100644 index 000000000..5211e00c4 --- /dev/null +++ b/target/linux/ep93xx/patches-2.6.39/002-mmc_spi_fix_sdhc.patch @@ -0,0 +1,74 @@ +This patch makes SDHC cards work with the mmc_spi driver. + +The problem is that they fail when reading the last block of the card using +a multi-block read. This is because on SDHC the multiple block read has to be +stopped with an explicit STOP command, which needs to be sent to the card +while the incoming transfer is in progress. +The 2.6.3[45] mmc-spi driver sends it after the last block transfer, so the +SDHC card continues reading past the end of the card. +This patch works around this by using single-block reads if we're reading the +last blocks of the card. + -martinwguy, 14 May 2010 + +Date: Thu, 29 Apr 2010 21:30:36 +0300 +From: Mika Westerberg <mika.westerberg@iki.fi> +To: Martin Guy <martinwguy@gmail.com> + +On Wed, Apr 21, 2010 at 02:10:08AM +0100, Martin Guy wrote: +> +> the SDHC cards I have don't work at all, spewing tons of: +> mmcblk0: error -38 sending status comand +> mmcblk0: error -38 sending read/write command, response 0x4, card status 0xff04 +> end_request: I/O error, dev mmcblk0, sector 7744509 + +I bought today a new 4GB SDHC card and with that I get similar +errors that you are getting. I hacked around quick fix which seems +to work in my case. I'm wondering whether you could check if it +helps with your SDHC card as well? + +This problem is easy to reproduce, just read last sector of the +card (I wrote simple C program but running fdisk -l does the same). + +Patch is below. + +Thanks, +MW + +From: Mika Westerberg <mika.westerberg@iki.fi> +Date: Thu, 29 Apr 2010 21:14:32 +0300 +Subject: [PATCH] mmc_block: use single block reads for last block on SPI + +Some SD-cards fail when doing multiblock read for last block with SPI host. Real +reason is not known but as workaround we can perform this last read using +multiple single block reads. + +Signed-off-by: Mika Westerberg <mika.westerberg@iki.fi> +--- + drivers/mmc/card/block.c | 19 +++++++++++++++++++ + 1 files changed, 19 insertions(+), 0 deletions(-) + +--- a/drivers/mmc/card/block.c ++++ b/drivers/mmc/card/block.c +@@ -366,6 +366,22 @@ static int mmc_blk_issue_rw_rq(struct mm + if (brq.data.blocks > card->host->max_blk_count) + brq.data.blocks = card->host->max_blk_count; + ++ if (mmc_host_is_spi(card->host)) { ++ /* ++ * Some SD-cards fail when we are reading last block ++ * with multiblock read. In these cases we automatically ++ * use single block reads. This only happens on SPI ++ * hosts. ++ */ ++ if (rq_data_dir(req) == READ && brq.data.blocks > 1) { ++ sector_t s = blk_rq_pos(req) + brq.data.blocks; ++ ++ if (s >= get_capacity(md->disk)) { ++ disable_multi = 1; ++ } ++ } ++ } ++ + /* + * After a read error, we redo the request one sector at a time + * in order to accurately determine which sectors can be read |