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>

1 files changed, 40 insertions, 40 deletions

diff --git a/drivers/mmc/host/msm_sdcc.c b/drivers/mmc/host/msm_sdcc.c
index 4c068e5fe6b2..977932a4bf4b 100644
--- 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);