mmc: msm_sdcc: Clean up clock management and add a 10us delay after enabling clocks

It appears that in some cases there may be a delay on the ARM9 in enabling our clock.
As a result, we may put the controller into a bad state. Delay 10us after enabling
clocks to let the peripheral settle. Note - this is all imperical.

Also ensure set_ios() callback grabs the host lock.

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 4c068e5..977932a 100644 (file)
--- a/drivers/mmc/host/msm_sdcc.c
+++ b/drivers/mmc/host/msm_sdcc.c
@@ -735,20 +735,42 @@ msmsdcc_request(struct mmc_host *mmc, struct mmc_request *mrq)
        spin_unlock_irqrestore(&host->lock, flags);
 }
 
+static int inline
+msmsdcc_enable_clocks(struct msmsdcc_host *host, int enable)
+{
+       int rc;
+       if (enable) {
+               rc = clk_enable(host->pclk);
+               if (rc)
+                       return rc;
+               rc = clk_enable(host->clk);
+               if (rc) {
+                       clk_disable(host->pclk);
+                       return rc;
+               }
+               host->clks_on = 1;
+               udelay(10);
+       } else {
+               clk_disable(host->clk);
+               clk_disable(host->pclk);
+               host->clks_on = 0;
+       }
+       return 0;
+}
+
 static void
 msmsdcc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 {
        struct msmsdcc_host *host = mmc_priv(mmc);
        u32 clk = 0, pwr = 0;
        int rc;
+       unsigned long flags;
 
+       spin_lock_irqsave(&host->lock, flags);
        if (ios->clock) {
 
-               if (!host->clks_on) {
-                       clk_enable(host->pclk);
-                       clk_enable(host->clk);
-                       host->clks_on = 1;
-               }
+               if (!host->clks_on)
+                       msmsdcc_enable_clocks(host, 1);
                if (ios->clock != host->clk_rate) {
                        rc = clk_set_rate(host->clk, ios->clock);
                        if (rc < 0)
@@ -793,11 +815,9 @@ msmsdcc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
                writel(pwr, host->base + MMCIPOWER);
        }
 
-       if (!(clk & MCI_CLK_ENABLE) && host->clks_on) {
-               clk_disable(host->clk);
-               clk_disable(host->pclk);
-               host->clks_on = 0;
-       }
+       if (!(clk & MCI_CLK_ENABLE) && host->clks_on)
+               msmsdcc_enable_clocks(host, 0);
+       spin_unlock_irqrestore(&host->lock, flags);
 }
 
 static void msmsdcc_enable_sdio_irq(struct mmc_host *mmc, int enable)
@@ -899,7 +919,6 @@ msmsdcc_command_expired(unsigned long _data)
        pr_err("%s: Command timeout (%p %p %p %p)\n",
               mmc_hostname(host->mmc), mrq, mrq->cmd,
               mrq->data, host->dma.sg);
-
        mrq->cmd->error = -ETIMEDOUT;
        msmsdcc_stop_data(host);
 
@@ -1031,31 +1050,21 @@ msmsdcc_probe(struct platform_device *pdev)
         */
        msmsdcc_init_dma(host);
 
-       /*
-        * Setup main peripheral bus clock
-        */
+       /* Get our clocks */
        host->pclk = clk_get(&pdev->dev, "sdc_pclk");
        if (IS_ERR(host->pclk)) {
                ret = PTR_ERR(host->pclk);
                goto host_free;
        }
 
-       ret = clk_enable(host->pclk);
-       if (ret)
-               goto pclk_put;
-
-       host->pclk_rate = clk_get_rate(host->pclk);
-
-       /*
-        * Setup SDC MMC clock
-        */
        host->clk = clk_get(&pdev->dev, "sdc_clk");
        if (IS_ERR(host->clk)) {
                ret = PTR_ERR(host->clk);
-               goto pclk_disable;
+               goto pclk_put;
        }
 
-       ret = clk_enable(host->clk);
+       /* Enable clocks */
+       ret = msmsdcc_enable_clocks(host, 1);
        if (ret)
                goto clk_put;
 
@@ -1065,10 +1074,9 @@ msmsdcc_probe(struct platform_device *pdev)
                goto clk_disable;
        }
 
+       host->pclk_rate = clk_get_rate(host->pclk);
        host->clk_rate = clk_get_rate(host->clk);
 
-       host->clks_on = 1;
-
        /*
         * Setup MMC host structure
         */
@@ -1187,11 +1195,9 @@ msmsdcc_probe(struct platform_device *pdev)
        if (host->stat_irq)
                free_irq(host->stat_irq, host);
  clk_disable:
-       clk_disable(host->clk);
+       msmsdcc_enable_clocks(host, 0);
  clk_put:
        clk_put(host->clk);
- pclk_disable:
-       clk_disable(host->pclk);
  pclk_put:
        clk_put(host->pclk);
  host_free:
@@ -1217,11 +1223,8 @@ msmsdcc_suspend(struct platform_device *dev, pm_message_t state)
                if (!rc) {
                        writel(0, host->base + MMCIMASK0);
 
-                       if (host->clks_on) {
-                               clk_disable(host->clk);
-                               clk_disable(host->pclk);
-                               host->clks_on = 0;
-                       }
+                       if (host->clks_on)
+                               msmsdcc_enable_clocks(host, 0);
                }
        }
        return rc;
@@ -1238,11 +1241,8 @@ msmsdcc_resume(struct platform_device *dev)
 
                spin_lock_irqsave(&host->lock, flags);
 
-               if (!host->clks_on) {
-                       clk_enable(host->pclk);
-                       clk_enable(host->clk);
-                       host->clks_on = 1;
-               }
+               if (!host->clks_on)
+                       msmsdcc_enable_clocks(host, 1);
 
                writel(host->saved_irq0mask, host->base + MMCIMASK0);