cpm2: Fix race condition in CPM2 GPIO library.

The CPM2 GPIO library code uses the non thread-safe clrbits32/setbits32
macros. This patch protects them with a spinlock.
Signed-off-by: Laurent Pinchart <laurentp@cse-semaphore.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

arch/powerpc/sysdev/cpm_common.c

@@ -254,15 +254,11 @@ static int cpm2_gpio32_get(struct gpio_chip *gc, unsigned int gpio)
 	return !!(in_be32(&iop->dat) & pin_mask);
 }
 
-static void cpm2_gpio32_set(struct gpio_chip *gc, unsigned int gpio, int value)
+static void __cpm2_gpio32_set(struct of_mm_gpio_chip *mm_gc, u32 pin_mask,
+	int value)
 {
-	struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
 	struct cpm2_gpio32_chip *cpm2_gc = to_cpm2_gpio32_chip(mm_gc);
 	struct cpm2_ioports __iomem *iop = mm_gc->regs;
-	unsigned long flags;
-	u32 pin_mask = 1 << (31 - gpio);
-
-	spin_lock_irqsave(&cpm2_gc->lock, flags);
 
 	if (value)
 		cpm2_gc->cpdata |= pin_mask;
@@ -270,6 +266,18 @@ static void cpm2_gpio32_set(struct gpio_chip *gc, unsigned int gpio, int value)
 		cpm2_gc->cpdata &= ~pin_mask;
 
 	out_be32(&iop->dat, cpm2_gc->cpdata);
+}
+
+static void cpm2_gpio32_set(struct gpio_chip *gc, unsigned int gpio, int value)
+{
+	struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
+	struct cpm2_gpio32_chip *cpm2_gc = to_cpm2_gpio32_chip(mm_gc);
+	unsigned long flags;
+	u32 pin_mask = 1 << (31 - gpio);
+
+	spin_lock_irqsave(&cpm2_gc->lock, flags);
+
+	__cpm2_gpio32_set(mm_gc, pin_mask, value);
 
 	spin_unlock_irqrestore(&cpm2_gc->lock, flags);
 }
@@ -277,14 +285,17 @@ static void cpm2_gpio32_set(struct gpio_chip *gc, unsigned int gpio, int value)
 static int cpm2_gpio32_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
 {
 	struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
+	struct cpm2_gpio32_chip *cpm2_gc = to_cpm2_gpio32_chip(mm_gc);
 	struct cpm2_ioports __iomem *iop = mm_gc->regs;
-	u32 pin_mask;
+	unsigned long flags;
+	u32 pin_mask = 1 << (31 - gpio);
 
-	pin_mask = 1 << (31 - gpio);
+	spin_lock_irqsave(&cpm2_gc->lock, flags);
 
 	setbits32(&iop->dir, pin_mask);
+	__cpm2_gpio32_set(mm_gc, pin_mask, val);
 
-	cpm2_gpio32_set(gc, gpio, val);
+	spin_unlock_irqrestore(&cpm2_gc->lock, flags);
 
 	return 0;
 }
@@ -292,13 +303,17 @@ static int cpm2_gpio32_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
 static int cpm2_gpio32_dir_in(struct gpio_chip *gc, unsigned int gpio)
 {
 	struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
+	struct cpm2_gpio32_chip *cpm2_gc = to_cpm2_gpio32_chip(mm_gc);
 	struct cpm2_ioports __iomem *iop = mm_gc->regs;
-	u32 pin_mask;
+	unsigned long flags;
+	u32 pin_mask = 1 << (31 - gpio);
 
-	pin_mask = 1 << (31 - gpio);
+	spin_lock_irqsave(&cpm2_gc->lock, flags);
 
 	clrbits32(&iop->dir, pin_mask);
 
+	spin_unlock_irqrestore(&cpm2_gc->lock, flags);
+
 	return 0;
 }