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>

diff --git a/drivers/mmc/host/msm_sdcc.c b/drivers/mmc/host/msm_sdcc.c
index 8329fd6..47b1f25 100644 (file)
--- 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);
        }