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Subject[PATCH] mmc: change mmc_delay() to use usleep_range()
Date
Use the usleep_range() to simplify mmc_delay() and give some more
accuracy to it - but with an exception of mmc_card_sleepawake():
since sleep/awake timeout varies in a wide range, different
delay methods should be used.

Signed-off-by: Dmitry Antipov <dmitry.antipov@linaro.org>
---
drivers/mmc/core/core.h | 8 ++------
drivers/mmc/core/mmc_ops.c | 12 +++++++++---
2 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
index 14664f1..a77851e 100644
--- a/drivers/mmc/core/core.h
+++ b/drivers/mmc/core/core.h
@@ -47,12 +47,8 @@ void mmc_power_off(struct mmc_host *host);

static inline void mmc_delay(unsigned int ms)
{
- if (ms < 1000 / HZ) {
- cond_resched();
- mdelay(ms);
- } else {
- msleep(ms);
- }
+ unsigned long us = ms * USEC_PER_MSEC;
+ usleep_range(us, us + 1000);
}

void mmc_rescan(struct work_struct *work);
diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
index 4d41fa9..38d53ac 100644
--- a/drivers/mmc/core/mmc_ops.c
+++ b/drivers/mmc/core/mmc_ops.c
@@ -82,9 +82,15 @@ int mmc_card_sleepawake(struct mmc_host *host, int sleep)
* SEND_STATUS command to poll the status because that command (and most
* others) is invalid while the card sleeps.
*/
- if (!(host->caps & MMC_CAP_WAIT_WHILE_BUSY))
- mmc_delay(DIV_ROUND_UP(card->ext_csd.sa_timeout, 10000));
-
+ if (!(host->caps & MMC_CAP_WAIT_WHILE_BUSY)) {
+ /* JEDEC MMCA 4.41 specifies the timeout value is in 200ns..838.86ms
+ range. Round it up to 1us and use an appropriate delay method. */
+ unsigned long us = DIV_ROUND_UP(card->ext_csd.sa_timeout, 10);
+ if (us < 10)
+ udelay(us);
+ else
+ usleep_range(us, us + 100);
+ }
if (!sleep)
err = mmc_select_card(card);

--
1.7.7.5


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