pinctrl: cherryview: Serialize register access in suspend/resume

If async suspend is enabled, the driver may access registers concurrently
with another instance which may fail because of the bug in Cherryview GPIO
hardware. Prevent this by taking the shared lock while accessing the
hardware in suspend and resume hooks.

Cc: stable@vger.kernel.org
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/pinctrl/intel/pinctrl-cherryview.c b/drivers/pinctrl/intel/pinctrl-cherryview.c
index 30389f4ccab4935c20ddcbed2c5a543e77d33fc5..097d835b3a508287ca54342f2f1bd381f68c8a2d 100644 (file)
--- a/drivers/pinctrl/intel/pinctrl-cherryview.c
+++ b/drivers/pinctrl/intel/pinctrl-cherryview.c
@@ -1656,8 +1656,11 @@ static int chv_pinctrl_suspend(struct device *dev)
 {
        struct platform_device *pdev = to_platform_device(dev);
        struct chv_pinctrl *pctrl = platform_get_drvdata(pdev);
+       unsigned long flags;
        int i;
 
+       raw_spin_lock_irqsave(&chv_lock, flags);
+
        pctrl->saved_intmask = readl(pctrl->regs + CHV_INTMASK);
 
        for (i = 0; i < pctrl->community->npins; i++) {
@@ -1678,6 +1681,8 @@ static int chv_pinctrl_suspend(struct device *dev)
                ctx->padctrl1 = readl(reg);
        }
 
+       raw_spin_unlock_irqrestore(&chv_lock, flags);
+
        return 0;
 }
 
@@ -1685,8 +1690,11 @@ static int chv_pinctrl_resume(struct device *dev)
 {
        struct platform_device *pdev = to_platform_device(dev);
        struct chv_pinctrl *pctrl = platform_get_drvdata(pdev);
+       unsigned long flags;
        int i;
 
+       raw_spin_lock_irqsave(&chv_lock, flags);
+
        /*
         * Mask all interrupts before restoring per-pin configuration
         * registers because we don't know in which state BIOS left them
@@ -1731,6 +1739,8 @@ static int chv_pinctrl_resume(struct device *dev)
        chv_writel(0xffff, pctrl->regs + CHV_INTSTAT);
        chv_writel(pctrl->saved_intmask, pctrl->regs + CHV_INTMASK);
 
+       raw_spin_unlock_irqrestore(&chv_lock, flags);
+
        return 0;
 }
 #endif