mmc: sdhci-pxav3: fix race between runtime pm and irq

commit 3bb10f60933e84abfe2be69f60b3486f9b96348b upstream.

This patch is to fix a race condition that may cause an unhandled irq,
which results in big sdhci interrupt numbers and endless "mmc1: got irq
while runtime suspended" msgs before v3.15.

Consider following scenario:

      CPU0                            CPU1
                              sdhci_pxav3_runtime_suspend()
                               spin_lock_irqsave(&host->lock, flags);
 sdhci_irq()
  spining on the &host->lock
                               host->runtime_suspended = true;
                               spin_unlock_irqrestore(&host->lock, flags);
  get the &host->lock
  runtime_suspended is true now
  return IRQ_NONE;

Fix this race by using the core sdhci.c supplied sdhci_runtime_suspend_host()
in runtime suspend hook which will disable card interrupts. We also use the
sdhci_runtime_resume_host() in the runtime resume hook accordingly.

Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

diff --git a/drivers/mmc/host/sdhci-pxav3.c b/drivers/mmc/host/sdhci-pxav3.c
index f62655bc1604f4bd7d013cc8bca0acae7daba341..a30f42003fb80a056c4eb113bc64195b69ff2ee8 100644 (file)
--- a/drivers/mmc/host/sdhci-pxav3.c
+++ b/drivers/mmc/host/sdhci-pxav3.c
@@ -448,11 +448,11 @@ static int sdhci_pxav3_runtime_suspend(struct device *dev)
 {
        struct sdhci_host *host = dev_get_drvdata(dev);
        struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
-       unsigned long flags;
+       int ret;
 
-       spin_lock_irqsave(&host->lock, flags);
-       host->runtime_suspended = true;
-       spin_unlock_irqrestore(&host->lock, flags);
+       ret = sdhci_runtime_suspend_host(host);
+       if (ret)
+               return ret;
 
        clk_disable_unprepare(pltfm_host->clk);
 
@@ -463,15 +463,10 @@ static int sdhci_pxav3_runtime_resume(struct device *dev)
 {
        struct sdhci_host *host = dev_get_drvdata(dev);
        struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
-       unsigned long flags;
 
        clk_prepare_enable(pltfm_host->clk);
 
-       spin_lock_irqsave(&host->lock, flags);
-       host->runtime_suspended = false;
-       spin_unlock_irqrestore(&host->lock, flags);
-
-       return 0;
+       return sdhci_runtime_resume_host(host);
 }
 #endif