soc: qcom: icc-bwmon: Allow for interrupts to be shared across instances

The multiple BWMONv4 instances available on the X1E80100 SoC use the
same interrupt number. Mark them are shared to allow for re-use across
instances.

Using IRQF_SHARED coupled with devm_request_threaded_irq implies that
the irq can still trigger during/after bwmon_remove due to other active
bwmon instances. Handle this race by relying on bwmon_disable to disable
the interrupt and coupled with explicit request/free irqs.

Signed-off-by: Sibi Sankar <[email protected]>
Reviewed-by: Dmitry Baryshkov <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Bjorn Andersson <[email protected]>

Author: Sibi Sankar

drivers/soc/qcom/icc-bwmon.c

@@ -783,9 +783,14 @@ static int bwmon_probe(struct platform_device *pdev)
 	bwmon->dev = dev;
 
 	bwmon_disable(bwmon);
-	ret = devm_request_threaded_irq(dev, bwmon->irq, bwmon_intr,
-					bwmon_intr_thread,
-					IRQF_ONESHOT, dev_name(dev), bwmon);
+
+	/*
+	 * SoCs with multiple cpu-bwmon instances can end up using a shared interrupt
+	 * line. Using the devm_ variant might result in the IRQ handler being executed
+	 * after bwmon_disable in bwmon_remove()
+	 */
+	ret = request_threaded_irq(bwmon->irq, bwmon_intr, bwmon_intr_thread,
+				   IRQF_ONESHOT | IRQF_SHARED, dev_name(dev), bwmon);
 	if (ret)
 		return dev_err_probe(dev, ret, "failed to request IRQ\n");
 
@@ -800,6 +805,7 @@ static void bwmon_remove(struct platform_device *pdev)
 	struct icc_bwmon *bwmon = platform_get_drvdata(pdev);
 
 	bwmon_disable(bwmon);
+	free_irq(bwmon->irq, bwmon);
 }
 
 static const struct icc_bwmon_data msm8998_bwmon_data = {