From fa5501890d8974301042e0202d342a6cbe8609f4 Mon Sep 17 00:00:00 2001 From: Ulf Hansson Date: Wed, 9 May 2012 16:15:26 +0200 Subject: [PATCH] mmc: core: Prevent eMMC VCC supply to be cut from late init For eMMC cards that has been initialized from a bootloader, the VCC voltage supply must not be cut in an uncontrolled manner, without first sending SLEEP or POWEROFF_NOTIFY. The regulator_init_complete late initcall, may cut the VCC regulator if it's reference counter is zero. To be able to prevent the regulator from being cut, mmc_start_host, which should execute at device init and thus before late init, calls mmc_power_up. Then the host driver is able to increase the reference to the regulator. Signed-off-by: Ulf Hansson Reviewed-by: Mark Brown Signed-off-by: Chris Ball --- drivers/mmc/core/core.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index ba821fe70bca..0b6141d29dbd 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -42,6 +42,7 @@ #include "sdio_ops.h" static struct workqueue_struct *workqueue; +static const unsigned freqs[] = { 400000, 300000, 200000, 100000 }; /* * Enabling software CRCs on the data blocks can be a significant (30%) @@ -1157,6 +1158,9 @@ static void mmc_power_up(struct mmc_host *host) { int bit; + if (host->ios.power_mode == MMC_POWER_ON) + return; + mmc_host_clk_hold(host); /* If ocr is set, we use it */ @@ -1199,6 +1203,10 @@ static void mmc_power_up(struct mmc_host *host) void mmc_power_off(struct mmc_host *host) { int err = 0; + + if (host->ios.power_mode == MMC_POWER_OFF) + return; + mmc_host_clk_hold(host); host->ios.clock = 0; @@ -2005,7 +2013,6 @@ EXPORT_SYMBOL(mmc_detect_card_removed); void mmc_rescan(struct work_struct *work) { - static const unsigned freqs[] = { 400000, 300000, 200000, 100000 }; struct mmc_host *host = container_of(work, struct mmc_host, detect.work); int i; @@ -2044,8 +2051,12 @@ void mmc_rescan(struct work_struct *work) */ mmc_bus_put(host); - if (host->ops->get_cd && host->ops->get_cd(host) == 0) + if (host->ops->get_cd && host->ops->get_cd(host) == 0) { + mmc_claim_host(host); + mmc_power_off(host); + mmc_release_host(host); goto out; + } mmc_claim_host(host); for (i = 0; i < ARRAY_SIZE(freqs); i++) { @@ -2063,7 +2074,8 @@ void mmc_rescan(struct work_struct *work) void mmc_start_host(struct mmc_host *host) { - mmc_power_off(host); + host->f_init = max(freqs[0], host->f_min); + mmc_power_up(host); mmc_detect_change(host, 0); } -- GitLab