| Message ID | 20240624092214.146935-4-quic_sibis@quicinc.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | arm64: dts: qcom: x1e80100: Enable bwmon support | expand |
On Mon, Jun 24, 2024 at 02:52:13PM GMT, Sibi Sankar wrote: > 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 <quic_sibis@quicinc.com> > --- > Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
diff --git a/drivers/soc/qcom/icc-bwmon.c b/drivers/soc/qcom/icc-bwmon.c index ecddb60bd665..e7851974084b 100644 --- a/drivers/soc/qcom/icc-bwmon.c +++ b/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 = {
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 <quic_sibis@quicinc.com> --- v3: * Update commit message describing the race condition. [Bjorn] * Update comment in the bwmon driver. [Dmitry] drivers/soc/qcom/icc-bwmon.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-)