| Message ID | 20241210-s2r-cdns-v6-2-28a17f9715a2@bootlin.com |
|---|---|
| State | New |
| Headers | show |
| Series | Fix USB suspend on TI J7200 (cdns3-ti, cdns3, xhci) | expand |
On 10/12/2024 19:13, Théo Lebrun wrote: > At runtime_resume(), read the W1 (Wrapper Register 1) register to detect > if an hardware reset occurred. If it did, run the hardware init sequence. > > This callback will be called at system-wide resume. Previously, if a > reset occurred during suspend, we would crash. The wrapper config had > not been written, leading to invalid register accesses inside cdns3. > Did I understand right that the Controller reset can happen only at system suspend and never at runtime suspend? If so do you really need the runtime suspend/resume hooks? you should have different system suspend/resume hooks than runtime suspend/resume hooks and deal with the re-initialization in system resume hook. > Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com> > --- > drivers/usb/cdns3/cdns3-ti.c | 25 +++++++++++++++++++++++++ > 1 file changed, 25 insertions(+) > > diff --git a/drivers/usb/cdns3/cdns3-ti.c b/drivers/usb/cdns3/cdns3-ti.c > index d704eb39820ad08a8774be7f00aa473c3ff267c0..d35be7db7616ef5e5bed7dbd53b78a094809f7cc 100644 > --- a/drivers/usb/cdns3/cdns3-ti.c > +++ b/drivers/usb/cdns3/cdns3-ti.c > @@ -188,6 +188,12 @@ static int cdns_ti_probe(struct platform_device *pdev) > data->vbus_divider = device_property_read_bool(dev, "ti,vbus-divider"); > data->usb2_only = device_property_read_bool(dev, "ti,usb2-only"); > > + /* > + * The call below to pm_runtime_get_sync() MIGHT reset hardware, if it > + * detects it as uninitialised. We want to enforce a reset at probe, > + * and so do it manually here. This means the first runtime_resume() > + * will be a no-op. > + */ Separate system sleep hooks will also prevent this kind of behavior. > cdns_ti_reset_and_init_hw(data); > > pm_runtime_enable(dev); > @@ -232,6 +238,24 @@ static void cdns_ti_remove(struct platform_device *pdev) > platform_set_drvdata(pdev, NULL); > } > > +static int cdns_ti_runtime_resume(struct device *dev) > +{ > + const u32 mask = USBSS_W1_PWRUP_RST | USBSS_W1_MODESTRAP_SEL; > + struct cdns_ti *data = dev_get_drvdata(dev); > + u32 w1; > + > + w1 = cdns_ti_readl(data, USBSS_W1); > + if ((w1 & mask) != mask) > + cdns_ti_reset_and_init_hw(data); > + > + return 0; > +} > + > +static const struct dev_pm_ops cdns_ti_pm_ops = { > + RUNTIME_PM_OPS(NULL, cdns_ti_runtime_resume, NULL) > + SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, pm_runtime_force_resume) > +}; > + > static const struct of_device_id cdns_ti_of_match[] = { > { .compatible = "ti,j721e-usb", }, > { .compatible = "ti,am64-usb", }, > @@ -245,6 +269,7 @@ static struct platform_driver cdns_ti_driver = { > .driver = { > .name = "cdns3-ti", > .of_match_table = cdns_ti_of_match, > + .pm = pm_ptr(&cdns_ti_pm_ops), > }, > }; > >
diff --git a/drivers/usb/cdns3/cdns3-ti.c b/drivers/usb/cdns3/cdns3-ti.c index d704eb39820ad08a8774be7f00aa473c3ff267c0..d35be7db7616ef5e5bed7dbd53b78a094809f7cc 100644 --- a/drivers/usb/cdns3/cdns3-ti.c +++ b/drivers/usb/cdns3/cdns3-ti.c @@ -188,6 +188,12 @@ static int cdns_ti_probe(struct platform_device *pdev) data->vbus_divider = device_property_read_bool(dev, "ti,vbus-divider"); data->usb2_only = device_property_read_bool(dev, "ti,usb2-only"); + /* + * The call below to pm_runtime_get_sync() MIGHT reset hardware, if it + * detects it as uninitialised. We want to enforce a reset at probe, + * and so do it manually here. This means the first runtime_resume() + * will be a no-op. + */ cdns_ti_reset_and_init_hw(data); pm_runtime_enable(dev); @@ -232,6 +238,24 @@ static void cdns_ti_remove(struct platform_device *pdev) platform_set_drvdata(pdev, NULL); } +static int cdns_ti_runtime_resume(struct device *dev) +{ + const u32 mask = USBSS_W1_PWRUP_RST | USBSS_W1_MODESTRAP_SEL; + struct cdns_ti *data = dev_get_drvdata(dev); + u32 w1; + + w1 = cdns_ti_readl(data, USBSS_W1); + if ((w1 & mask) != mask) + cdns_ti_reset_and_init_hw(data); + + return 0; +} + +static const struct dev_pm_ops cdns_ti_pm_ops = { + RUNTIME_PM_OPS(NULL, cdns_ti_runtime_resume, NULL) + SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, pm_runtime_force_resume) +}; + static const struct of_device_id cdns_ti_of_match[] = { { .compatible = "ti,j721e-usb", }, { .compatible = "ti,am64-usb", }, @@ -245,6 +269,7 @@ static struct platform_driver cdns_ti_driver = { .driver = { .name = "cdns3-ti", .of_match_table = cdns_ti_of_match, + .pm = pm_ptr(&cdns_ti_pm_ops), }, };
At runtime_resume(), read the W1 (Wrapper Register 1) register to detect if an hardware reset occurred. If it did, run the hardware init sequence. This callback will be called at system-wide resume. Previously, if a reset occurred during suspend, we would crash. The wrapper config had not been written, leading to invalid register accesses inside cdns3. Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com> --- drivers/usb/cdns3/cdns3-ti.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+)