[PATCH v2 2/9] gpio: mxc: fix wakeup_pads bit operations

[Peng Fan (OSS)]

From: Peng Fan <peng.fan at nxp.com>

gpio_set_wake_irq() can be called concurrently for different pins on
the same port, so need to use atomic bitops when modifying wakeup_pads.

Since wakeup_pads is u32 but assign_bit() operate on unsigned long
pointers. On 64-bit platforms this causes an 8-byte read-modify-write
on a 4-byte field, corrupting the adjacent is_pad_wakeup member.
Change wakeup_pads to unsigned long and reorder to avoid the overlap.

And the enable/disable path unconditionally sets/clears the wakeup_pads
bit even when enable_irq_wake()/disable_irq_wake() fails. Only update
the bit on success.

While at here, simplify the logic by consolidating into a single
irq_set_irq_wake() call based on the enable parameter.

Fixes: f60c9eac54af ("gpio: mxc: enable pad wakeup on i.MX8x platforms")
Assisted-by: LLM
Signed-off-by: Peng Fan <peng.fan at nxp.com>
---
 drivers/gpio/gpio-mxc.c | 52 ++++++++++++++++++++++---------------------------
 1 file changed, 23 insertions(+), 29 deletions(-)

diff --git a/drivers/gpio/gpio-mxc.c b/drivers/gpio/gpio-mxc.c
index e05f276a50e8..0013f73d23bf 100644
--- a/drivers/gpio/gpio-mxc.c
+++ b/drivers/gpio/gpio-mxc.c
@@ -71,8 +71,8 @@ struct mxc_gpio_port {
 	u32 both_edges;
 	struct mxc_gpio_reg_saved gpio_saved_reg;
 	bool power_off;
-	u32 wakeup_pads;
 	bool is_pad_wakeup;
+	unsigned long wakeup_pads;
 	u32 pad_type[32];
 	const struct mxc_gpio_hwdata *hwdata;
 };
@@ -325,21 +325,17 @@ static int gpio_set_wake_irq(struct irq_data *d, u32 enable)
 	u32 gpio_idx = d->hwirq;
 	int ret;
 
-	if (enable) {
-		if (port->irq_high && (gpio_idx >= 16))
-			ret = enable_irq_wake(port->irq_high);
-		else
-			ret = enable_irq_wake(port->irq);
-		port->wakeup_pads |= BIT(gpio_idx);
-	} else {
-		if (port->irq_high && (gpio_idx >= 16))
-			ret = disable_irq_wake(port->irq_high);
-		else
-			ret = disable_irq_wake(port->irq);
-		port->wakeup_pads &= ~BIT(gpio_idx);
-	}
+	if (port->irq_high && (gpio_idx >= 16))
+		ret = irq_set_irq_wake(port->irq_high, enable);
+	else
+		ret = irq_set_irq_wake(port->irq, enable);
 
-	return ret;
+	if (ret)
+		return ret;
+
+	assign_bit(gpio_idx, &port->wakeup_pads, enable);
+
+	return 0;
 }
 
 static int mxc_gpio_init_gc(struct mxc_gpio_port *port, int irq_base)
@@ -598,22 +594,20 @@ static bool mxc_gpio_set_pad_wakeup(struct mxc_gpio_port *port, bool enable)
 		IMX_SCU_WAKEUP_LOW_LVL,		/* IRQ_TYPE_LEVEL_LOW */
 	};
 
-	for (i = 0; i < 32; i++) {
-		if ((port->wakeup_pads & (1 << i))) {
-			type = port->pad_type[i];
-			if (enable)
-				config = pad_type_map[type];
-			else
-				config = IMX_SCU_WAKEUP_OFF;
-
-			if (is_imx8qm && config == IMX_SCU_WAKEUP_FALL_EDGE) {
-				dev_warn_once(port->dev,
-					      "No falling-edge support for wakeup on i.MX8QM\n");
-				config = IMX_SCU_WAKEUP_OFF;
-			}
+	for_each_set_bit(i, &port->wakeup_pads, 32) {
+		type = port->pad_type[i];
+		if (enable)
+			config = pad_type_map[type];
+		else
+			config = IMX_SCU_WAKEUP_OFF;
 
-			ret |= mxc_gpio_generic_config(port, i, config);
+		if (is_imx8qm && config == IMX_SCU_WAKEUP_FALL_EDGE) {
+			dev_warn_once(port->dev,
+				      "No falling-edge support for wakeup on i.MX8QM\n");
+			config = IMX_SCU_WAKEUP_OFF;
 		}
+
+		ret |= mxc_gpio_generic_config(port, i, config);
 	}
 
 	return ret;

-- 
2.51.0