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git://projects.qi-hardware.com/openwrt-xburst.git
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75 lines
2.7 KiB
Diff
75 lines
2.7 KiB
Diff
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This patch makes SDHC cards work with the mmc_spi driver.
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The problem is that they fail when reading the last block of the card using
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a multi-block read. This is because on SDHC the multiple block read has to be
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stopped with an explicit STOP command, which needs to be sent to the card
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while the incoming transfer is in progress.
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The 2.6.3[45] mmc-spi driver sends it after the last block transfer, so the
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SDHC card continues reading past the end of the card.
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This patch works around this by using single-block reads if we're reading the
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last blocks of the card.
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-martinwguy, 14 May 2010
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Date: Thu, 29 Apr 2010 21:30:36 +0300
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From: Mika Westerberg <mika.westerberg@iki.fi>
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To: Martin Guy <martinwguy@gmail.com>
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On Wed, Apr 21, 2010 at 02:10:08AM +0100, Martin Guy wrote:
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>
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> the SDHC cards I have don't work at all, spewing tons of:
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> mmcblk0: error -38 sending status comand
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> mmcblk0: error -38 sending read/write command, response 0x4, card status 0xff04
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> end_request: I/O error, dev mmcblk0, sector 7744509
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I bought today a new 4GB SDHC card and with that I get similar
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errors that you are getting. I hacked around quick fix which seems
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to work in my case. I'm wondering whether you could check if it
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helps with your SDHC card as well?
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This problem is easy to reproduce, just read last sector of the
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card (I wrote simple C program but running fdisk -l does the same).
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Patch is below.
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Thanks,
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MW
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From: Mika Westerberg <mika.westerberg@iki.fi>
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Date: Thu, 29 Apr 2010 21:14:32 +0300
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Subject: [PATCH] mmc_block: use single block reads for last block on SPI
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Some SD-cards fail when doing multiblock read for last block with SPI host. Real
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reason is not known but as workaround we can perform this last read using
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multiple single block reads.
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Signed-off-by: Mika Westerberg <mika.westerberg@iki.fi>
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---
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drivers/mmc/card/block.c | 19 +++++++++++++++++++
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1 files changed, 19 insertions(+), 0 deletions(-)
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--- a/drivers/mmc/card/block.c
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+++ b/drivers/mmc/card/block.c
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@@ -351,6 +351,22 @@ static int mmc_blk_issue_rw_rq(struct mm
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if (brq.data.blocks > card->host->max_blk_count)
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brq.data.blocks = card->host->max_blk_count;
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+ if (mmc_host_is_spi(card->host)) {
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+ /*
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+ * Some SD-cards fail when we are reading last block
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+ * with multiblock read. In these cases we automatically
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+ * use single block reads. This only happens on SPI
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+ * hosts.
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+ */
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+ if (rq_data_dir(req) == READ && brq.data.blocks > 1) {
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+ sector_t s = blk_rq_pos(req) + brq.data.blocks;
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+
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+ if (s >= get_capacity(md->disk)) {
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+ disable_multi = 1;
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+ }
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+ }
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+ }
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+
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/*
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* After a read error, we redo the request one sector at a time
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* in order to accurately determine which sectors can be read
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