linux-kernel - [PATCH v2 4/4] pinctrl: rockchip: Protect read-modify-write with the spinlock

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Date:	Tue, 21 Oct 2014 10:47:35 -0700
From:	Doug Anderson <dianders@...omium.org>
To:	Linus Walleij <linus.walleij@...aro.org>,
	Heiko Stuebner <heiko@...ech.de>
Cc:	Chris Zhong <zyw@...k-chips.com>,
	Sonny Rao <sonnyrao@...omium.org>,
	linux-rockchip@...ts.infradead.org,
	linux-arm-kernel@...ts.infradead.org,
	Doug Anderson <dianders@...omium.org>,
	linux-kernel@...r.kernel.org
Subject: [PATCH v2 4/4] pinctrl: rockchip: Protect read-modify-write with the spinlock

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 <dianders@...omium.org>
---
Changes in v2:
- Made sure to release the lock in an error condition.

 drivers/pinctrl/pinctrl-rockchip.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/pinctrl/pinctrl-rockchip.c b/drivers/pinctrl/pinctrl-rockchip.c
index 6c14f6c..59a5461 100644
--- a/drivers/pinctrl/pinctrl-rockchip.c
+++ b/drivers/pinctrl/pinctrl-rockchip.c
@@ -861,6 +861,7 @@ static int _rockchip_pmx_gpio_set_direction(struct gpio_chip *chip,
 {
 	struct rockchip_pin_bank *bank;
 	int ret;
+	unsigned long flags;
 	u32 data;
 
 	bank = gc_to_pin_bank(chip);
@@ -869,6 +870,8 @@ static int _rockchip_pmx_gpio_set_direction(struct gpio_chip *chip,
 	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)
@@ -877,6 +880,8 @@ static int _rockchip_pmx_gpio_set_direction(struct gpio_chip *chip,
 		data &= ~BIT(pin);
 	writel_relaxed(data, bank->reg_base + GPIO_SWPORT_DDR);
 
+	spin_unlock_irqrestore(&bank->slock, flags);
+
 	return 0;
 }
 
@@ -1394,6 +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);
 
@@ -1439,10 +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);
@@ -1456,6 +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 */
@@ -1463,15 +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);
@@ -1514,6 +1530,7 @@ static int rockchip_irq_set_type(struct irq_data *d, unsigned int type)
 		break;
 	default:
 		irq_gc_unlock(gc);
+		spin_unlock_irqrestore(&bank->slock, flags);
 		return -EINVAL;
 	}
 
@@ -1521,6 +1538,7 @@ 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;
 }
-- 
2.1.0.rc2.206.gedb03e5

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