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mmc: core: Fixup suspend/resume issues for UHS-I cards
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Even if cards supports 1.8V I/O voltage those should anyway be
initialized at 3.3V I/O according to (e)MMC, SD and SDIO specs.
Some eMMC and embedded SDIO devices are able to be initialized
at 1.8V as well, but it is better to be safe.

Do note that initialization in this context means that the card
has been completely powered off, otherwise the card will remain
at the last I/O voltage level that were negotitiated.

Due to the above being taken care of the suspend/resume issues
for UHS-I SD-cards has been fixed.

Signed-off-by: Ulf Hansson <ulf.hansson@stericsson.com>
Acked-by: Philip Rakity <prakity@marvell.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
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Ulf Hansson authored and Chris Ball committed Mar 4, 2012
1 parent 8f7f6b7 commit e774747
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Showing 4 changed files with 17 additions and 5 deletions.
3 changes: 3 additions & 0 deletions drivers/mmc/core/core.c
Original file line number Diff line number Diff line change
Expand Up @@ -2068,6 +2068,9 @@ static int mmc_rescan_try_freq(struct mmc_host *host, unsigned freq)
*/
mmc_hw_reset_for_init(host);

/* Initialization should be done at 3.3 V I/O voltage. */
mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_330, 0);

/*
* sdio_reset sends CMD52 to reset card. Since we do not know
* if the card is being re-initialized, just send it. CMD52
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3 changes: 3 additions & 0 deletions drivers/mmc/core/mmc.c
Original file line number Diff line number Diff line change
Expand Up @@ -816,6 +816,9 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
if (!mmc_host_is_spi(host))
mmc_set_bus_mode(host, MMC_BUSMODE_OPENDRAIN);

/* Initialization should be done at 3.3 V I/O voltage. */
mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_330, 0);

/*
* Since we're changing the OCR value, we seem to
* need to tell some cards to go back to the idle
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8 changes: 3 additions & 5 deletions drivers/mmc/core/sd.c
Original file line number Diff line number Diff line change
Expand Up @@ -911,6 +911,9 @@ static int mmc_sd_init_card(struct mmc_host *host, u32 ocr,
BUG_ON(!host);
WARN_ON(!host->claimed);

/* The initialization should be done at 3.3 V I/O voltage. */
mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_330, 0);

err = mmc_sd_get_cid(host, ocr, cid, &rocr);
if (err)
return err;
Expand Down Expand Up @@ -1156,11 +1159,6 @@ int mmc_attach_sd(struct mmc_host *host)
BUG_ON(!host);
WARN_ON(!host->claimed);

/* Make sure we are at 3.3V signalling voltage */
err = mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_330, false);
if (err)
return err;

/* Disable preset value enable if already set since last time */
if (host->ops->enable_preset_value) {
mmc_host_clk_hold(host);
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8 changes: 8 additions & 0 deletions drivers/mmc/core/sdio.c
Original file line number Diff line number Diff line change
Expand Up @@ -585,6 +585,9 @@ static int mmc_sdio_init_card(struct mmc_host *host, u32 ocr,
* Inform the card of the voltage
*/
if (!powered_resume) {
/* The initialization should be done at 3.3 V I/O voltage. */
mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_330, 0);

err = mmc_send_io_op_cond(host, host->ocr, &ocr);
if (err)
goto err;
Expand Down Expand Up @@ -996,6 +999,11 @@ static int mmc_sdio_power_restore(struct mmc_host *host)
* With these steps taken, mmc_select_voltage() is also required to
* restore the correct voltage setting of the card.
*/

/* The initialization should be done at 3.3 V I/O voltage. */
if (!mmc_card_keep_power(host))
mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_330, 0);

sdio_reset(host);
mmc_go_idle(host);
mmc_send_if_cond(host, host->ocr_avail);
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