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SubjectRe: [MMC] Fix SD timeout calculation
On Sun, Jun 18, 2006 at 02:34:37PM +0200, Pierre Ossman wrote:
> Secure Digital cards use a different algorithm to calculate the timeout
> for data transfers. Using the MMC one works often, but not always.

Applied, thanks.

I'm wondering about this cleanup though - both the timeout calculations
appear to be identical, so making this a library function seems to be
the right way to go... unless you know different?

diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index c0c7ef2..74eaaee 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -247,6 +247,55 @@ int mmc_wait_for_app_cmd(struct mmc_host

EXPORT_SYMBOL(mmc_wait_for_app_cmd);

+/**
+ * mmc_set_data_timeout - set the timeout for a data command
+ * @data: data phase for command
+ * @card: the MMC card associated with the data transfer
+ * @write: flag to differentiate reads from writes
+ */
+void mmc_set_data_timeout(struct mmc_data *data, const struct mmc_card *card,
+ int write)
+{
+ unsigned int mult;
+
+ /*
+ * SD cards use a 100 multiplier rather than 10
+ */
+ mult = mmc_card_sd(card) ? 100 : 10;
+
+ /*
+ * Scale up the multiplier (and therefore the timeout) by
+ * the r2w factor for writes.
+ */
+ if (write)
+ mult <<= card->csd.r2w_factor;
+
+ data->timeout_ns = card->csd.tacc_ns * mult;
+ data->timeout_clks = card->csd.tacc_clks * mult;
+
+ /*
+ * SD cards also have an upper limit on the timeout.
+ */
+ if (mmc_card_sd(card)) {
+ unsigned int timeout_us, limit_us;
+
+ timeout_us = data->timeout_ns / 1000;
+ timeout_us += data->timeout_clks * 1000 /
+ (card->host->ios.clock / 1000);
+
+ if (write)
+ limit_us = 250000;
+ else
+ limit_us = 100000;
+
+ if (timeout_us > limit_us) {
+ data->timeout_ns = limit_us * 1000;
+ data->timeout_clks = 0;
+ }
+ }
+}
+EXPORT_SYMBOL(mmc_set_data_timeout);
+
static int mmc_select_card(struct mmc_host *host, struct mmc_card *card);

/**
@@ -908,12 +957,9 @@ static void mmc_read_scrs(struct mmc_hos
{
int err;
struct mmc_card *card;
-
struct mmc_request mrq;
struct mmc_command cmd;
struct mmc_data data;
- unsigned int timeout_us;
-
struct scatterlist sg;

list_for_each_entry(card, &host->cards, node) {
@@ -948,17 +994,7 @@ static void mmc_read_scrs(struct mmc_hos

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

- 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;
- }
+ mmc_set_data_timeout(&data, card, 0);

data.blksz_bits = 3;
data.blksz = 1 << 3;
diff --git a/drivers/mmc/mmc_block.c b/drivers/mmc/mmc_block.c
index 515fb22..d6fcc46 100644
--- a/drivers/mmc/mmc_block.c
+++ b/drivers/mmc/mmc_block.c
@@ -179,40 +179,7 @@ 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;
- }
- }
+ mmc_set_data_timeout(&brq.data, card, rq_data_dir(req) != READ);

if (rq_data_dir(req) == READ) {
brq.cmd.opcode = brq.data.blocks > 1 ? MMC_READ_MULTIPLE_BLOCK : MMC_READ_SINGLE_BLOCK;
diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
index 03a14a3..627e2c0 100644
--- a/include/linux/mmc/mmc.h
+++ b/include/linux/mmc/mmc.h
@@ -105,6 +105,8 @@ extern int mmc_wait_for_cmd(struct mmc_h
extern int mmc_wait_for_app_cmd(struct mmc_host *, unsigned int,
struct mmc_command *, int);

+extern void mmc_set_data_timeout(struct mmc_data *, const struct mmc_card *, int);
+
extern int __mmc_claim_host(struct mmc_host *host, struct mmc_card *card);

static inline void mmc_claim_host(struct mmc_host *host)
-
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