mmc: core: Ensure clocks are always enabled before host interaction

Ensure clocks are always enabled before any interaction with the
host controller driver. This makes sure that there is no race
between host execution and the core layer turning off clocks
in different context with clock gating framework.

Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Per Forlin <per.forlin@stericsson.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

1 files changed, 18 insertions, 4 deletions

diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index c63ad03c29c7..5017f9354ce2 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -451,9 +451,11 @@ static int sd_select_driver_type(struct mmc_card *card, u8 *status)
          * information and let the hardware specific code
          * return what is possible given the options
          */
+        mmc_host_clk_hold(card->host);
         drive_strength = card->host->ops->select_drive_strength(
                 card->sw_caps.uhs_max_dtr,
                 host_drv_type, card_drv_type);
+        mmc_host_clk_release(card->host);
 
         err = mmc_sd_switch(card, 1, 2, drive_strength, status);
         if (err)
@@ -660,9 +662,12 @@ static int mmc_sd_init_uhs_card(struct mmc_card *card)
                 goto out;
 
         /* SPI mode doesn't define CMD19 */
-        if (!mmc_host_is_spi(card->host) && card->host->ops->execute_tuning)
+        if (!mmc_host_is_spi(card->host) && card->host->ops->execute_tuning) {
+                mmc_host_clk_hold(card->host);
                 err = card->host->ops->execute_tuning(card->host,
                                                       MMC_SEND_TUNING_BLOCK);
+                mmc_host_clk_release(card->host);
+        }
 
 out:
         kfree(status);
@@ -850,8 +855,11 @@ int mmc_sd_setup_card(struct mmc_host *host, struct mmc_card *card,
         if (!reinit) {
                 int ro = -1;
 
-                if (host->ops->get_ro)
+                if (host->ops->get_ro) {
+                        mmc_host_clk_hold(card->host);
                         ro = host->ops->get_ro(host);
+                        mmc_host_clk_release(card->host);
+                }
 
                 if (ro < 0) {
                         pr_warning("%s: host does not "
@@ -967,8 +975,11 @@ static int mmc_sd_init_card(struct mmc_host *host, u32 ocr,
                  * Since initialization is now complete, enable preset
                  * value registers for UHS-I cards.
                  */
-                if (host->ops->enable_preset_value)
+                if (host->ops->enable_preset_value) {
+                        mmc_host_clk_hold(card->host);
                         host->ops->enable_preset_value(host, true);
+                        mmc_host_clk_release(card->host);
+                }
         } else {
                 /*
                  * Attempt to change to high-speed (if supported)
@@ -1151,8 +1162,11 @@ int mmc_attach_sd(struct mmc_host *host)
                 return err;
 
         /* Disable preset value enable if already set since last time */
-        if (host->ops->enable_preset_value)
+        if (host->ops->enable_preset_value) {
+                mmc_host_clk_hold(host);
                 host->ops->enable_preset_value(host, false);
+                mmc_host_clk_release(host);
+        }
 
         err = mmc_send_app_op_cond(host, 0, &ocr);
         if (err)