[4/4] pinctrl: rockchip: Protect read-modify-write with the spinlock

Commit Message

Doug Anderson Oct. 20, 2014, 11:27 p.m. UTC

There were a few instances where the rockchip pinctrl driver would do
read-modify-write with no spinlock.  Add a spinlock for these cases.

Signed-off-by: Doug Anderson <[e-mail]>
---
 drivers/pinctrl/pinctrl-rockchip.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

Comments

Doug Anderson Oct. 20, 2014, 11:57 p.m. UTC | #1

Hi,

On Mon, Oct 20, 2014 at 4:27 PM, Doug Anderson <[e-mail]> wrote:
> @@ -1464,15 +1474,20 @@ static int rockchip_irq_set_type(struct irq_data *d, unsigned int type)
>         if (ret < 0)
>                 return ret;
>
> +       spin_lock_irqsave(&bank->slock, flags);
> +
>         data = readl_relaxed(bank->reg_base + GPIO_SWPORT_DDR);
>         data &= ~mask;
>         writel_relaxed(data, bank->reg_base + GPIO_SWPORT_DDR);
>
> +       spin_unlock_irqrestore(&bank->slock, flags);
> +
>         if (type & IRQ_TYPE_EDGE_BOTH)
>                 __irq_set_handler_locked(d->irq, handle_edge_irq);
>         else
>                 __irq_set_handler_locked(d->irq, handle_level_irq);
>
> +       spin_lock_irqsave(&bank->slock, flags);
>         irq_gc_lock(gc);
>
>         level = readl_relaxed(gc->reg_base + GPIO_INTTYPE_LEVEL);
> @@ -1522,6 +1537,7 @@ static int rockchip_irq_set_type(struct irq_data *d, unsigned int type)
>         writel_relaxed(polarity, gc->reg_base + GPIO_INT_POLARITY);
>
>         irq_gc_unlock(gc);
> +       spin_unlock_irqrestore(&bank->slock, flags);

I just reviewed this again myself and I realized that there was an
error path case that I missed.  I'll plan to spin tomorrow and include
any extra feedback people have.

I'll also note that I'd love any extra scrutiny people have on this
patch.  I'm submitting it totally based on code inspection and am
nowhere near an expert on this driver.  I mostly just looked for all
of the read/modify/wites using writel and added the lock...

-Doug

Patch

diff --git a/drivers/pinctrl/pinctrl-rockchip.c b/drivers/pinctrl/pinctrl-rockchip.c
index 14a5683..669e5e8 100644
--- a/drivers/pinctrl/pinctrl-rockchip.c
+++ b/drivers/pinctrl/pinctrl-rockchip.c
@@ -871,6 +871,8 @@  static int _rockchip_pmx_gpio_set_direction(struct gpio_chip *gc,
 	if (ret < 0)
 		return ret;
 
+	spin_lock_irqsave(&bank->slock, flags);
+
 	data = readl_relaxed(bank->reg_base + GPIO_SWPORT_DDR);
 	/* set bit to 1 for output, 0 for input */
 	if (!input)
@@ -879,6 +881,8 @@  static int _rockchip_pmx_gpio_set_direction(struct gpio_chip *gc,
 		data &= ~BIT(pin);
 	writel_relaxed(data, bank->reg_base + GPIO_SWPORT_DDR);
 
+	spin_unlock_irqrestore(&bank->slock, flags);
+
 	return 0;
 }
 
@@ -1395,6 +1399,7 @@  static void rockchip_irq_demux(unsigned int irq, struct irq_desc *desc)
 	u32 polarity = 0, data = 0;
 	u32 pend;
 	bool edge_changed = false;
+	unsigned long flags;
 
 	dev_dbg(bank->drvdata->dev, "got irq for bank %s\n", bank->name);
 
@@ -1440,10 +1445,14 @@  static void rockchip_irq_demux(unsigned int irq, struct irq_desc *desc)
 
 	if (bank->toggle_edge_mode && edge_changed) {
 		/* Interrupt params should only be set with ints disabled */
+		spin_lock_irqsave(&bank->slock, flags);
+
 		data = readl_relaxed(bank->reg_base + GPIO_INTEN);
 		writel_relaxed(0, bank->reg_base + GPIO_INTEN);
 		writel(polarity, bank->reg_base + GPIO_INT_POLARITY);
 		writel(data, bank->reg_base + GPIO_INTEN);
+
+		spin_unlock_irqrestore(&bank->slock, flags);
 	}
 
 	chained_irq_exit(chip, desc);
@@ -1457,6 +1466,7 @@  static int rockchip_irq_set_type(struct irq_data *d, unsigned int type)
 	u32 polarity;
 	u32 level;
 	u32 data;
+	unsigned long flags;
 	int ret;
 
 	/* make sure the pin is configured as gpio input */
@@ -1464,15 +1474,20 @@  static int rockchip_irq_set_type(struct irq_data *d, unsigned int type)
 	if (ret < 0)
 		return ret;
 
+	spin_lock_irqsave(&bank->slock, flags);
+
 	data = readl_relaxed(bank->reg_base + GPIO_SWPORT_DDR);
 	data &= ~mask;
 	writel_relaxed(data, bank->reg_base + GPIO_SWPORT_DDR);
 
+	spin_unlock_irqrestore(&bank->slock, flags);
+
 	if (type & IRQ_TYPE_EDGE_BOTH)
 		__irq_set_handler_locked(d->irq, handle_edge_irq);
 	else
 		__irq_set_handler_locked(d->irq, handle_level_irq);
 
+	spin_lock_irqsave(&bank->slock, flags);
 	irq_gc_lock(gc);
 
 	level = readl_relaxed(gc->reg_base + GPIO_INTTYPE_LEVEL);
@@ -1522,6 +1537,7 @@  static int rockchip_irq_set_type(struct irq_data *d, unsigned int type)
 	writel_relaxed(polarity, gc->reg_base + GPIO_INT_POLARITY);
 
 	irq_gc_unlock(gc);
+	spin_unlock_irqrestore(&bank->slock, flags);
 
 	return 0;
 }