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, 16 insertions, 3 deletions

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index f545a3e6eb80..b3063b741df3 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -290,8 +290,11 @@ static void mmc_wait_for_req_done(struct mmc_host *host,
 static void mmc_pre_req(struct mmc_host *host, struct mmc_request *mrq,
                  bool is_first_req)
 {
-        if (host->ops->pre_req)
+        if (host->ops->pre_req) {
+                mmc_host_clk_hold(host);
                 host->ops->pre_req(host, mrq, is_first_req);
+                mmc_host_clk_release(host);
+        }
 }
 
 /**
@@ -306,8 +309,11 @@ static void mmc_pre_req(struct mmc_host *host, struct mmc_request *mrq,
 static void mmc_post_req(struct mmc_host *host, struct mmc_request *mrq,
                          int err)
 {
-        if (host->ops->post_req)
+        if (host->ops->post_req) {
+                mmc_host_clk_hold(host);
                 host->ops->post_req(host, mrq, err);
+                mmc_host_clk_release(host);
+        }
 }
 
 /**
@@ -620,7 +626,9 @@ int mmc_host_enable(struct mmc_host *host)
                 int err;
 
                 host->en_dis_recurs = 1;
+                mmc_host_clk_hold(host);
                 err = host->ops->enable(host);
+                mmc_host_clk_release(host);
                 host->en_dis_recurs = 0;
 
                 if (err) {
@@ -640,7 +648,9 @@ static int mmc_host_do_disable(struct mmc_host *host, int lazy)
                 int err;
 
                 host->en_dis_recurs = 1;
+                mmc_host_clk_hold(host);
                 err = host->ops->disable(host, lazy);
+                mmc_host_clk_release(host);
                 host->en_dis_recurs = 0;
 
                 if (err < 0) {
@@ -1203,8 +1213,11 @@ int mmc_set_signal_voltage(struct mmc_host *host, int signal_voltage, bool cmd11
 
         host->ios.signal_voltage = signal_voltage;
 
-        if (host->ops->start_signal_voltage_switch)
+        if (host->ops->start_signal_voltage_switch) {
+                mmc_host_clk_hold(host);
                 err = host->ops->start_signal_voltage_switch(host, &host->ios);
+                mmc_host_clk_release(host);
+        }
 
         return err;
 }