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mmc: core: fix improper clock frequency being passed to set_ios

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This bug was introduced in the 'MMC-4.5 Power OFF Notify Rework' fix.

Prior to the aforementioned patch, during resume mmc_init_card was being
invoked. The aforesaid patch invokes mmc_card_awake, prior to which
mmc_power_up has already set the clock frequency to 400Khz. Since the card
init is not done again, this frequency stays as is and results in data
time-out errors.

Two new functions
	* mmc_save_ios
	* mmc_restore_ios
were added.
The mmc_save_ios is invoked during mmc_suspend process and it saves the
current ios values, while mmc_restore_ios is invoked during mmc_resume process
and restores the previous ios values before sending the awake command. This
ensures that the clock, timing, bus-width etc are set properly before any
request is sent to the driver.

Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
This commit is contained in:
Asutosh Das
2012-05-28 17:27:20 +05:30
committed by Stephen Boyd
parent 06d8e2a3ad
commit 460cee698a
2 changed files with 28 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

27
drivers/mmc/core/mmc.c
View File

@@ -1430,6 +1430,31 @@ static void mmc_detect(struct mmc_host *host)
} }
} }
/*
* Save ios settings
*/
static void mmc_save_ios(struct mmc_host *host)
{
BUG_ON(!host);
mmc_host_clk_hold(host);
memcpy(&host->saved_ios, &host->ios, sizeof(struct mmc_ios));
mmc_host_clk_release(host);
}
/*
* Restore ios setting
*/
static void mmc_restore_ios(struct mmc_host *host)
{
BUG_ON(!host);
memcpy(&host->ios, &host->saved_ios, sizeof(struct mmc_ios));
mmc_set_ios(host);
}
/* /*
* Suspend callback from host. * Suspend callback from host.
*/ */
@@ -1441,6 +1466,7 @@ static int mmc_suspend(struct mmc_host *host)
BUG_ON(!host->card); BUG_ON(!host->card);
mmc_claim_host(host); mmc_claim_host(host);
mmc_save_ios(host);
if (mmc_can_poweroff_notify(host->card) && if (mmc_can_poweroff_notify(host->card) &&
(host->caps2 & MMC_CAP2_POWER_OFF_VCCQ_DURING_SUSPEND)) { (host->caps2 & MMC_CAP2_POWER_OFF_VCCQ_DURING_SUSPEND)) {
err = mmc_poweroff_notify(host, MMC_PW_OFF_NOTIFY_SHORT); err = mmc_poweroff_notify(host, MMC_PW_OFF_NOTIFY_SHORT);
@@ -1473,6 +1499,7 @@ static int mmc_resume(struct mmc_host *host)
mmc_claim_host(host); mmc_claim_host(host);
if (mmc_card_is_sleep(host->card)) { if (mmc_card_is_sleep(host->card)) {
mmc_restore_ios(host);
err = mmc_card_awake(host); err = mmc_card_awake(host);
} else } else
err = mmc_init_card(host, host->ocr, host->card); err = mmc_init_card(host, host->ocr, host->card);

1
include/linux/mmc/host.h
View File

@@ -352,6 +352,7 @@ struct mmc_host {
} perf; } perf;
bool perf_enable; bool perf_enable;
#endif #endif
struct mmc_ios saved_ios;
unsigned long private[0] ____cacheline_aligned; unsigned long private[0] ____cacheline_aligned;
}; };