* Nishanth Menon <nm@xxxxxx> [131203 17:40]: > Due to the cross dependencies between hwmod for automanaged device > information for OMAP and dts node definitions, we can run into scenarios > where the dts node is defined, however it's hwmod entry is yet to be > added. In these cases: > a) omap_device does not register a pm_domain (since it cannot find > hwmod entry). > b) driver does not know about (a), does a pm_runtime_get_sync which > never fails > c) It then tries to do some operation on the device (such as read the > revision register (as part of probe) without clock or adequate OMAP > generic PM operation performed for enabling the module. > > This causes a crash such as that reported in: > https://bugzilla.kernel.org/show_bug.cgi?id=66441 > > When 'ti,hwmod' is provided in dt node, it is expected that the device > will not function without the OMAP's power automanagement. Hence, when > we hit a fail condition (due to hwmod entries not present or other > similar scenario), fail at pm_domain level due to lack of data, provide > enough information for it to be fixed, however, it allows for the driver > to take appropriate measures to prevent crash. Kevin, any comments on this one? Regards, Tony > Reported-by: Tobias Jakobi <tjakobi@xxxxxxxxxxxxxxxxxxxxx> > Signed-off-by: Nishanth Menon <nm@xxxxxx> > --- > arch/arm/mach-omap2/omap_device.c | 24 ++++++++++++++++++++++++ > arch/arm/mach-omap2/omap_device.h | 1 + > 2 files changed, 25 insertions(+) > > diff --git a/arch/arm/mach-omap2/omap_device.c b/arch/arm/mach-omap2/omap_device.c > index 53f0735..e0a398c 100644 > --- a/arch/arm/mach-omap2/omap_device.c > +++ b/arch/arm/mach-omap2/omap_device.c > @@ -183,6 +183,10 @@ static int omap_device_build_from_dt(struct platform_device *pdev) > odbfd_exit1: > kfree(hwmods); > odbfd_exit: > + /* if data/we are at fault.. load up a fail handler */ > + if (ret) > + pdev->dev.pm_domain = &omap_device_fail_pm_domain; > + > return ret; > } > > @@ -604,6 +608,19 @@ static int _od_runtime_resume(struct device *dev) > > return pm_generic_runtime_resume(dev); > } > + > +static int _od_fail_runtime_suspend(struct device *dev) > +{ > + dev_warn(dev, "%s: FIXME: missing hwmod/omap_dev info\n", __func__); > + return -ENODEV; > +} > + > +static int _od_fail_runtime_resume(struct device *dev) > +{ > + dev_warn(dev, "%s: FIXME: missing hwmod/omap_dev info\n", __func__); > + return -ENODEV; > +} > + > #endif > > #ifdef CONFIG_SUSPEND > @@ -657,6 +674,13 @@ static int _od_resume_noirq(struct device *dev) > #define _od_resume_noirq NULL > #endif > > +struct dev_pm_domain omap_device_fail_pm_domain = { > + .ops = { > + SET_RUNTIME_PM_OPS(_od_fail_runtime_suspend, > + _od_fail_runtime_resume, NULL) > + } > +}; > + > struct dev_pm_domain omap_device_pm_domain = { > .ops = { > SET_RUNTIME_PM_OPS(_od_runtime_suspend, _od_runtime_resume, > diff --git a/arch/arm/mach-omap2/omap_device.h b/arch/arm/mach-omap2/omap_device.h > index 17ca1ae..78c02b3 100644 > --- a/arch/arm/mach-omap2/omap_device.h > +++ b/arch/arm/mach-omap2/omap_device.h > @@ -29,6 +29,7 @@ > #include "omap_hwmod.h" > > extern struct dev_pm_domain omap_device_pm_domain; > +extern struct dev_pm_domain omap_device_fail_pm_domain; > > /* omap_device._state values */ > #define OMAP_DEVICE_STATE_UNKNOWN 0 > -- > 1.7.9.5 > -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
