mmc: msm_sdcc: Fix issue where clocks could be disabled mid transaction

msmsdcc_enable_clocks() was incorrectly being called depending on
the state of host->clks_on. This means the busclk idle timer was never
being deleted if the clock was already on.. Bogus.

    Also fixes a possible double clk disable if the call to
del_timer_sync() in msmsdcc_disable_clocks() raced with
the busclk timer.

Signed-off-by: San Mehat <san@google.com>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>

1 files changed, 27 insertions, 34 deletions

diff --git a/drivers/mmc/host/msm_sdcc.c b/drivers/mmc/host/msm_sdcc.c
index 8329fd650c5f..47b1f2526521 100644
--- a/drivers/mmc/host/msm_sdcc.c
+++ b/drivers/mmc/host/msm_sdcc.c
@@ -61,7 +61,7 @@ static unsigned int msmsdcc_sdioirq;
 #define CMD_SPINMAX 20
 
 
-static inline void 
+static inline void
 msmsdcc_disable_clocks(struct msmsdcc_host *host, int deferr)
 {
         WARN_ON(!host->clks_on);
@@ -72,9 +72,14 @@ msmsdcc_disable_clocks(struct msmsdcc_host *host, int deferr)
                 mod_timer(&host->busclk_timer, jiffies + BUSCLK_TIMEOUT);
         } else {
                 del_timer_sync(&host->busclk_timer);
-                clk_disable(host->clk);
-                clk_disable(host->pclk);
-                host->clks_on = 0;
+                /* Need to check clks_on again in case the busclk
+                 * timer fired
+                 */
+                if (host->clks_on) {
+                        clk_disable(host->clk);
+                        clk_disable(host->pclk);
+                        host->clks_on = 0;
+                }
         }
 }
 
@@ -83,21 +88,21 @@ msmsdcc_enable_clocks(struct msmsdcc_host *host)
 {
         int rc;
 
-        WARN_ON(host->clks_on);
-
         del_timer_sync(&host->busclk_timer);
 
-        rc = clk_enable(host->pclk);
-        if (rc)
-                return rc;
-        rc = clk_enable(host->clk);
-        if (rc) {
-                clk_disable(host->pclk);
-                return rc;
+        if (!host->clks_on) {
+                rc = clk_enable(host->pclk);
+                if (rc)
+                        return rc;
+                rc = clk_enable(host->clk);
+                if (rc) {
+                        clk_disable(host->pclk);
+                        return rc;
+                }
+                udelay(1 + ((3 * USEC_PER_SEC) /
+                       (host->clk_rate ? host->clk_rate : msmsdcc_fmin)));
+                host->clks_on = 1;
         }
-        udelay(1 + ((3 * USEC_PER_SEC) /
-               (host->clk_rate ? host->clk_rate : msmsdcc_fmin)));
-        host->clks_on = 1;
         return 0;
 }
 
@@ -180,7 +185,8 @@ msmsdcc_dma_exec_func(struct msm_dmov_cmd *cmd)
         struct msmsdcc_host *host = (struct msmsdcc_host *)cmd->data;
 
         msmsdcc_writel(host, host->cmd_timeout, MMCIDATATIMER);
-        msmsdcc_writel(host, (unsigned int)host->curr.xfer_size, MMCIDATALENGTH);
+        msmsdcc_writel(host, (unsigned int)host->curr.xfer_size,
+                       MMCIDATALENGTH);
         msmsdcc_writel(host, host->cmd_pio_irqmask, MMCIMASK1);
         msmsdcc_writel(host, host->cmd_datactrl, MMCIDATACTRL);
 
@@ -854,13 +860,7 @@ msmsdcc_request(struct mmc_host *mmc, struct mmc_request *mrq)
                 return;
         }
 
-        /* Need to drop the host lock here in case
-         * the busclk wd fires 
-         */
-        spin_unlock_irqrestore(&host->lock, flags);
-        if (!host->clks_on)
-                msmsdcc_enable_clocks(host);
-        spin_lock_irqsave(&host->lock, flags);
+        msmsdcc_enable_clocks(host);
 
         host->curr.mrq = mrq;
 
@@ -893,11 +893,10 @@ msmsdcc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
         int rc;
         unsigned long flags;
 
-        if (!host->clks_on)
-                msmsdcc_enable_clocks(host);
-
         spin_lock_irqsave(&host->lock, flags);
 
+        msmsdcc_enable_clocks(host);
+
         if (ios->clock) {
                 if (ios->clock != host->clk_rate) {
                         rc = clk_set_rate(host->clk, ios->clock);
@@ -1026,13 +1025,9 @@ static void
 msmsdcc_busclk_expired(unsigned long _data)
 {
         struct msmsdcc_host     *host = (struct msmsdcc_host *) _data;
-        unsigned long           flags;
 
-        spin_lock_irqsave(&host->lock, flags);
-        dev_info(mmc_dev(host->mmc), "Bus clock timer expired\n");
         if (host->clks_on)
                 msmsdcc_disable_clocks(host, 0);
-        spin_unlock_irqrestore(&host->lock, flags);
 }
 
 static int
@@ -1324,10 +1319,8 @@ msmsdcc_suspend(struct platform_device *dev, pm_message_t state)
 
                 if (mmc->card && mmc->card->type != MMC_TYPE_SDIO)
                         rc = mmc_suspend_host(mmc, state);
-                if (!rc) {
+                if (!rc)
                         msmsdcc_writel(host, 0, MMCIMASK0);
-
-                }
                 if (host->clks_on)
                         msmsdcc_disable_clocks(host, 0);
         }