pinctrl: amd: Detect and mask spurious interrupts

Leverage gpiochip_line_is_irq to check whether a pin has an irq
associated with it. The previous check ("irq == 0") didn't make much
sense. The irq variable refers to the pinctrl irq, and has nothing do to
with an individual pin.

On some systems, during suspend/resume cycle, the firmware leaves
an interrupt enabled on a pin that is not used by the kernel.
Without this patch that caused an interrupt storm.

Cc: stable@vger.kernel.org
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217315Signed-off-by: Kornel Dulęba <korneld@chromium.org>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://lore.kernel.org/r/20230421120625.3366-4-mario.limonciello@amd.comSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/pinctrl-amd.c

@@ -660,21 +660,21 @@ static bool do_amd_gpio_irq_handler(int irq, void *dev_id)
 			 * We must read the pin register again, in case the
 			 * value was changed while executing
 			 * generic_handle_domain_irq() above.
-			 * If we didn't find a mapping for the interrupt,
-			 * disable it in order to avoid a system hang caused
-			 * by an interrupt storm.
+			 * If the line is not an irq, disable it in order to
+			 * avoid a system hang caused by an interrupt storm.
 			 */
 			raw_spin_lock_irqsave(&gpio_dev->lock, flags);
 			regval = readl(regs + i);
-			if (irq == 0) {
-				regval &= ~BIT(INTERRUPT_ENABLE_OFF);
+			if (!gpiochip_line_is_irq(gc, irqnr + i)) {
+				regval &= ~BIT(INTERRUPT_MASK_OFF);
 				dev_dbg(&gpio_dev->pdev->dev,
 					"Disabling spurious GPIO IRQ %d\n",
 					irqnr + i);
+			} else {
+				ret = true;
 			}
 			writel(regval, regs + i);
 			raw_spin_unlock_irqrestore(&gpio_dev->lock, flags);
-			ret = true;
 		}
 	}
 	/* did not cause wake on resume context for shared IRQ */