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SubjectRe: Support for TI FlashMedia (pci id 104c:8033, 104c:803b) flash card readers
Alex Dubov wrote:
> I also got a bug report from one of my users. Formerly, I used fixed timeout for data transfer,
> but now I'm setting a timeout from data->timeout_clks. This causes recurrent timeouts with some
> cards. Have you encountered this problem before? If yes, what will be the preferred solution?
>
>

Yup. The timeout calculation we currently have is broken with regard to
SD cards. Only some cards are affected though. Patch included.

Rgds
Pierre

[MMC] Fix SD timeout calculation

Secure Digital cards use a different algorithm to calculate the timeout
for data transfers. Using the MMC one works often, but not always.

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
---

drivers/mmc/mmc.c | 15 +++++++++++++--
drivers/mmc/mmc_block.c | 44 ++++++++++++++++++++++++++++++++++++--------
2 files changed, 49 insertions(+), 10 deletions(-)

diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index 33525bd..c0c7ef2 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -912,6 +912,7 @@ static void mmc_read_scrs(struct mmc_hos
struct mmc_request mrq;
struct mmc_command cmd;
struct mmc_data data;
+ unsigned int timeout_us;

struct scatterlist sg;

@@ -947,8 +948,18 @@ static void mmc_read_scrs(struct mmc_hos

memset(&data, 0, sizeof(struct mmc_data));

- data.timeout_ns = card->csd.tacc_ns * 10;
- data.timeout_clks = card->csd.tacc_clks * 10;
+ data.timeout_ns = card->csd.tacc_ns * 100;
+ data.timeout_clks = card->csd.tacc_clks * 100;
+
+ timeout_us = data.timeout_ns / 1000;
+ timeout_us += data.timeout_clks * 1000 /
+ (host->ios.clock / 1000);
+
+ if (timeout_us > 100000) {
+ data.timeout_ns = 100000000;
+ data.timeout_clks = 0;
+ }
+
data.blksz_bits = 3;
data.blksz = 1 << 3;
data.blocks = 1;
diff --git a/drivers/mmc/mmc_block.c b/drivers/mmc/mmc_block.c
index e033424..cb7fc8d 100644
--- a/drivers/mmc/mmc_block.c
+++ b/drivers/mmc/mmc_block.c
@@ -30,6 +30,7 @@ #include <linux/blkdev.h>
#include <linux/mutex.h>

#include <linux/mmc/card.h>
+#include <linux/mmc/host.h>
#include <linux/mmc/protocol.h>

#include <asm/system.h>
@@ -171,8 +172,6 @@ static int mmc_blk_issue_rq(struct mmc_q

brq.cmd.arg = req->sector << 9;
brq.cmd.flags = MMC_RSP_R1 | MMC_CMD_ADTC;
- brq.data.timeout_ns = card->csd.tacc_ns * 10;
- brq.data.timeout_clks = card->csd.tacc_clks * 10;
brq.data.blksz_bits = md->block_bits;
brq.data.blksz = 1 << md->block_bits;
brq.data.blocks = req->nr_sectors >> (md->block_bits - 9);
@@ -180,6 +179,41 @@ static int mmc_blk_issue_rq(struct mmc_q
brq.stop.arg = 0;
brq.stop.flags = MMC_RSP_R1B | MMC_CMD_AC;

+ brq.data.timeout_ns = card->csd.tacc_ns * 10;
+ brq.data.timeout_clks = card->csd.tacc_clks * 10;
+
+ /*
+ * Scale up the timeout by the r2w factor
+ */
+ if (rq_data_dir(req) == WRITE) {
+ brq.data.timeout_ns <<= card->csd.r2w_factor;
+ brq.data.timeout_clks <<= card->csd.r2w_factor;
+ }
+
+ /*
+ * SD cards use a 100 multiplier and has a upper limit
+ */
+ if (mmc_card_sd(card)) {
+ unsigned int limit_us, timeout_us;
+
+ brq.data.timeout_ns *= 10;
+ brq.data.timeout_clks *= 10;
+
+ if (rq_data_dir(req) == READ)
+ limit_us = 100000;
+ else
+ limit_us = 250000;
+
+ timeout_us = brq.data.timeout_ns / 1000;
+ timeout_us += brq.data.timeout_clks * 1000 /
+ (card->host->ios.clock / 1000);
+
+ if (timeout_us > limit_us) {
+ brq.data.timeout_ns = limit_us * 1000;
+ brq.data.timeout_clks = 0;
+ }
+ }
+
if (rq_data_dir(req) == READ) {
brq.cmd.opcode = brq.data.blocks > 1 ? MMC_READ_MULTIPLE_BLOCK : MMC_READ_SINGLE_BLOCK;
brq.data.flags |= MMC_DATA_READ;
@@ -187,12 +221,6 @@ static int mmc_blk_issue_rq(struct mmc_q
brq.cmd.opcode = MMC_WRITE_BLOCK;
brq.data.flags |= MMC_DATA_WRITE;
brq.data.blocks = 1;
-
- /*
- * Scale up the timeout by the r2w factor
- */
- brq.data.timeout_ns <<= card->csd.r2w_factor;
- brq.data.timeout_clks <<= card->csd.r2w_factor;
}

if (brq.data.blocks > 1) {
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