On Thu, Oct 21, 2021 at 02:55:01PM +0300, Dmitry Osipenko wrote:
> Older device-trees don't specify padctrl interrupt and xhci-tegra driver
> now fails to probe with -EINVAL using those device-trees. Check interrupt
> presence and disallow runtime PM suspension if it's missing to fix the
> trouble.
>
> Fixes: 971ee247060d ("usb: xhci: tegra: Enable ELPG for runtime/system PM")
> Reported-by: Nicolas Chauvet <kwizart@xxxxxxxxx>
> Tested-by: Nicolas Chauvet <kwizart@xxxxxxxxx>
> Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
> ---
> drivers/usb/host/xhci-tegra.c | 32 +++++++++++++++++++++-----------
> 1 file changed, 21 insertions(+), 11 deletions(-)
Thanks for typing this up. A couple of minor comments below.
> diff --git a/drivers/usb/host/xhci-tegra.c b/drivers/usb/host/xhci-tegra.c
> index 1bf494b649bd..47927a1df3dc 100644
> --- a/drivers/usb/host/xhci-tegra.c
> +++ b/drivers/usb/host/xhci-tegra.c
> @@ -1454,10 +1454,13 @@ static int tegra_xusb_probe(struct platform_device *pdev)
> goto put_padctl;
> }
>
> - tegra->padctl_irq = of_irq_get(np, 0);
> - if (tegra->padctl_irq <= 0) {
> - err = (tegra->padctl_irq == 0) ? -ENODEV : tegra->padctl_irq;
> - goto put_padctl;
> + /* Older device-trees don't specify padctrl interrupt */
> + if (of_property_read_bool(np, "interrupts")) {
Can't we just rely on the return value from of_irq_get() instead of
explicitly checking for the presence of the "interrupts" property? All
we really want is to make this interrupt optional. As far as I can tell,
of_irq_get() will return -EINVAL (via of_irq_parse_one() and then
of_property_read_u32_index()) if the property doesn't exist, so I'd
think it should be possible to turn this into something like this:
tegra->padctl_irq = of_irq_get(np, 0);
if (tegra->padctl_irq == -EINVAL)
tegra->padctl_irq = 0;
> + tegra->padctl_irq = of_irq_get(np, 0);
> + if (tegra->padctl_irq <= 0) {
> + err = (tegra->padctl_irq == 0) ? -ENODEV : tegra->padctl_irq;
> + goto put_padctl;
> + }
> }
>
> tegra->host_clk = devm_clk_get(&pdev->dev, "xusb_host");
> @@ -1696,11 +1699,15 @@ static int tegra_xusb_probe(struct platform_device *pdev)
> goto remove_usb3;
> }
>
> - err = devm_request_threaded_irq(&pdev->dev, tegra->padctl_irq, NULL, tegra_xusb_padctl_irq,
> - IRQF_ONESHOT, dev_name(&pdev->dev), tegra);
> - if (err < 0) {
> - dev_err(&pdev->dev, "failed to request padctl IRQ: %d\n", err);
> - goto remove_usb3;
> + if (tegra->padctl_irq) {
> + err = devm_request_threaded_irq(&pdev->dev, tegra->padctl_irq,
> + NULL, tegra_xusb_padctl_irq,
> + IRQF_ONESHOT, dev_name(&pdev->dev),
> + tegra);
> + if (err < 0) {
> + dev_err(&pdev->dev, "failed to request padctl IRQ: %d\n", err);
> + goto remove_usb3;
> + }
> }
>
> err = tegra_xusb_enable_firmware_messages(tegra);
> @@ -2132,7 +2139,7 @@ static __maybe_unused int tegra_xusb_suspend(struct device *dev)
> tegra->suspended = true;
> pm_runtime_disable(dev);
>
> - if (device_may_wakeup(dev)) {
> + if (device_may_wakeup(dev) && tegra->padctl_irq) {
I wondered if perhaps there was a way to make device_may_wakeup() return
false if we don't have that IRQ. Intuitively I would've thought that the
calls to device_wakeup_enable() and device_init_wakeup() set this all up
but after looking at the code I'm not sure if omitting them would
actually cause device_may_wakeup() to return false. That would certainly
be nicer than these double checks.
> if (enable_irq_wake(tegra->padctl_irq))
> dev_err(dev, "failed to enable padctl wakes\n");
> }
> @@ -2161,7 +2168,7 @@ static __maybe_unused int tegra_xusb_resume(struct device *dev)
> return err;
> }
>
> - if (device_may_wakeup(dev)) {
> + if (device_may_wakeup(dev) && tegra->padctl_irq) {
> if (disable_irq_wake(tegra->padctl_irq))
> dev_err(dev, "failed to disable padctl wakes\n");
> }
> @@ -2179,6 +2186,9 @@ static __maybe_unused int tegra_xusb_runtime_suspend(struct device *dev)
> struct tegra_xusb *tegra = dev_get_drvdata(dev);
> int ret;
>
> + if (!tegra->padctl_irq)
> + return -EOPNOTSUPP;
> +
Similarly, couldn't we enable all that runtime PM stuff conditionally so
that these functions would only ever get called when runtime PM is
actually available? That seems a bit nicer than having this return
-EOPNOTSUPP.
Thierry
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