| Message ID | 20220223134839.731138-1-hdegoede@redhat.com |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [1/2] i2c: designware: Lock the adapter while setting the suspended flag | expand |
On Wed, Feb 23, 2022 at 02:48:38PM +0100, Hans de Goede wrote: > Lock the adapter while setting the suspended flag, to ensure that other > locked code always sees the change immediately, rather then possibly using > a stale value. > > This involves splitting the suspend/resume callbacks into separate runtime > and normal suspend/resume calls. This is necessary because i2c_dw_xfer() > will get called by the i2c-core with the adapter locked and it in turn > calls the runtime-resume callback through pm_runtime_get_sync(). > > So the runtime versions of the suspend/resume callbacks cannot take > the adapter-lock. Note this patch simply makes the runtime suspend/resume > callbacks not deal with the suspended flag at all. During runtime the > pm_runtime_get_sync() from i2c_dw_xfer() will always ensure that the > adapter is resumed when necessary. > > The suspended flag check is only necessary to check proper suspend/resume > ordering during normal suspend/resume which makes the pm_runtime_get_sync() > call a no-op. Both patches look good to me and seems like a nice clean up. Not sure if the first one should be backported (and hence have a Fixes tag). Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > Signed-off-by: Hans de Goede <hdegoede@redhat.com> > --- > drivers/i2c/busses/i2c-designware-pcidrv.c | 31 +++++++++++++++++---- > drivers/i2c/busses/i2c-designware-platdrv.c | 31 +++++++++++++++++---- > 2 files changed, 52 insertions(+), 10 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-designware-pcidrv.c b/drivers/i2c/busses/i2c-designware-pcidrv.c > index ef4250f8852b..9553d7075223 100644 > --- a/drivers/i2c/busses/i2c-designware-pcidrv.c > +++ b/drivers/i2c/busses/i2c-designware-pcidrv.c > @@ -213,14 +213,30 @@ static struct dw_pci_controller dw_pci_controllers[] = { > }, > }; > > +static int __maybe_unused i2c_dw_pci_runtime_suspend(struct device *dev) > +{ > + struct dw_i2c_dev *i_dev = dev_get_drvdata(dev); > + > + i_dev->disable(i_dev); > + return 0; > +} > + > static int __maybe_unused i2c_dw_pci_suspend(struct device *dev) > { > struct dw_i2c_dev *i_dev = dev_get_drvdata(dev); > > + i2c_lock_bus(&i_dev->adapter, I2C_LOCK_ROOT_ADAPTER); > i_dev->suspended = true; > - i_dev->disable(i_dev); > + i2c_unlock_bus(&i_dev->adapter, I2C_LOCK_ROOT_ADAPTER); > > - return 0; > + return i2c_dw_pci_runtime_suspend(dev); > +} > + > +static int __maybe_unused i2c_dw_pci_runtime_resume(struct device *dev) > +{ > + struct dw_i2c_dev *i_dev = dev_get_drvdata(dev); > + > + return i_dev->init(i_dev); > } > > static int __maybe_unused i2c_dw_pci_resume(struct device *dev) > @@ -228,14 +244,19 @@ static int __maybe_unused i2c_dw_pci_resume(struct device *dev) > struct dw_i2c_dev *i_dev = dev_get_drvdata(dev); > int ret; > > - ret = i_dev->init(i_dev); > + ret = i2c_dw_pci_runtime_resume(dev); > + > + i2c_lock_bus(&i_dev->adapter, I2C_LOCK_ROOT_ADAPTER); > i_dev->suspended = false; > + i2c_unlock_bus(&i_dev->adapter, I2C_LOCK_ROOT_ADAPTER); > > return ret; > } > > -static UNIVERSAL_DEV_PM_OPS(i2c_dw_pm_ops, i2c_dw_pci_suspend, > - i2c_dw_pci_resume, NULL); > +static const struct dev_pm_ops i2c_dw_pm_ops = { > + SET_SYSTEM_SLEEP_PM_OPS(i2c_dw_pci_suspend, i2c_dw_pci_resume) > + SET_RUNTIME_PM_OPS(i2c_dw_pci_runtime_suspend, i2c_dw_pci_runtime_resume, NULL) > +}; > > static int i2c_dw_pci_probe(struct pci_dev *pdev, > const struct pci_device_id *id) > diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c > index 2bd81abc86f6..8e45f65bab73 100644 > --- a/drivers/i2c/busses/i2c-designware-platdrv.c > +++ b/drivers/i2c/busses/i2c-designware-platdrv.c > @@ -368,12 +368,10 @@ static void dw_i2c_plat_complete(struct device *dev) > #endif > > #ifdef CONFIG_PM > -static int dw_i2c_plat_suspend(struct device *dev) > +static int dw_i2c_plat_runtime_suspend(struct device *dev) > { > struct dw_i2c_dev *i_dev = dev_get_drvdata(dev); > > - i_dev->suspended = true; > - > if (i_dev->shared_with_punit) > return 0; > > @@ -383,7 +381,18 @@ static int dw_i2c_plat_suspend(struct device *dev) > return 0; > } > > -static int dw_i2c_plat_resume(struct device *dev) > +static int dw_i2c_plat_suspend(struct device *dev) > +{ > + struct dw_i2c_dev *i_dev = dev_get_drvdata(dev); > + > + i2c_lock_bus(&i_dev->adapter, I2C_LOCK_ROOT_ADAPTER); > + i_dev->suspended = true; > + i2c_unlock_bus(&i_dev->adapter, I2C_LOCK_ROOT_ADAPTER); > + > + return dw_i2c_plat_runtime_suspend(dev); > +} > + > +static int dw_i2c_plat_runtime_resume(struct device *dev) > { > struct dw_i2c_dev *i_dev = dev_get_drvdata(dev); > > @@ -391,7 +400,19 @@ static int dw_i2c_plat_resume(struct device *dev) > i2c_dw_prepare_clk(i_dev, true); > > i_dev->init(i_dev); > + > + return 0; > +} > + > +static int dw_i2c_plat_resume(struct device *dev) > +{ > + struct dw_i2c_dev *i_dev = dev_get_drvdata(dev); > + > + dw_i2c_plat_runtime_resume(dev); > + > + i2c_lock_bus(&i_dev->adapter, I2C_LOCK_ROOT_ADAPTER); > i_dev->suspended = false; > + i2c_unlock_bus(&i_dev->adapter, I2C_LOCK_ROOT_ADAPTER); > > return 0; > } > @@ -400,7 +421,7 @@ static const struct dev_pm_ops dw_i2c_dev_pm_ops = { > .prepare = dw_i2c_plat_prepare, > .complete = dw_i2c_plat_complete, > SET_LATE_SYSTEM_SLEEP_PM_OPS(dw_i2c_plat_suspend, dw_i2c_plat_resume) > - SET_RUNTIME_PM_OPS(dw_i2c_plat_suspend, dw_i2c_plat_resume, NULL) > + SET_RUNTIME_PM_OPS(dw_i2c_plat_runtime_suspend, dw_i2c_plat_runtime_resume, NULL) > }; > > #define DW_I2C_DEV_PMOPS (&dw_i2c_dev_pm_ops) > -- > 2.35.1 >
Hi Andy, On 2/23/22 15:52, Andy Shevchenko wrote: > On Wed, Feb 23, 2022 at 02:48:38PM +0100, Hans de Goede wrote: >> Lock the adapter while setting the suspended flag, to ensure that other >> locked code always sees the change immediately, rather then possibly using >> a stale value. >> >> This involves splitting the suspend/resume callbacks into separate runtime >> and normal suspend/resume calls. This is necessary because i2c_dw_xfer() >> will get called by the i2c-core with the adapter locked and it in turn >> calls the runtime-resume callback through pm_runtime_get_sync(). >> >> So the runtime versions of the suspend/resume callbacks cannot take >> the adapter-lock. Note this patch simply makes the runtime suspend/resume >> callbacks not deal with the suspended flag at all. During runtime the >> pm_runtime_get_sync() from i2c_dw_xfer() will always ensure that the >> adapter is resumed when necessary. >> >> The suspended flag check is only necessary to check proper suspend/resume >> ordering during normal suspend/resume which makes the pm_runtime_get_sync() >> call a no-op. > > Both patches look good to me and seems like a nice clean up. Not sure if the > first one should be backported (and hence have a Fixes tag). > > Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Thank you for the review. As for adding a Fixes: tag, this was inspired by an actual bug-report, but it did not help in fixing the bug, so I left the fixes tag out. If you or Wolfram still want to add a Fixes tag, then it should be: Fixes: 275154155538 ("i2c: designware: Do not allow i2c_dw_xfer() calls while suspended") Regards, Hans > >> Signed-off-by: Hans de Goede <hdegoede@redhat.com> >> --- >> drivers/i2c/busses/i2c-designware-pcidrv.c | 31 +++++++++++++++++---- >> drivers/i2c/busses/i2c-designware-platdrv.c | 31 +++++++++++++++++---- >> 2 files changed, 52 insertions(+), 10 deletions(-) >> >> diff --git a/drivers/i2c/busses/i2c-designware-pcidrv.c b/drivers/i2c/busses/i2c-designware-pcidrv.c >> index ef4250f8852b..9553d7075223 100644 >> --- a/drivers/i2c/busses/i2c-designware-pcidrv.c >> +++ b/drivers/i2c/busses/i2c-designware-pcidrv.c >> @@ -213,14 +213,30 @@ static struct dw_pci_controller dw_pci_controllers[] = { >> }, >> }; >> >> +static int __maybe_unused i2c_dw_pci_runtime_suspend(struct device *dev) >> +{ >> + struct dw_i2c_dev *i_dev = dev_get_drvdata(dev); >> + >> + i_dev->disable(i_dev); >> + return 0; >> +} >> + >> static int __maybe_unused i2c_dw_pci_suspend(struct device *dev) >> { >> struct dw_i2c_dev *i_dev = dev_get_drvdata(dev); >> >> + i2c_lock_bus(&i_dev->adapter, I2C_LOCK_ROOT_ADAPTER); >> i_dev->suspended = true; >> - i_dev->disable(i_dev); >> + i2c_unlock_bus(&i_dev->adapter, I2C_LOCK_ROOT_ADAPTER); >> >> - return 0; >> + return i2c_dw_pci_runtime_suspend(dev); >> +} >> + >> +static int __maybe_unused i2c_dw_pci_runtime_resume(struct device *dev) >> +{ >> + struct dw_i2c_dev *i_dev = dev_get_drvdata(dev); >> + >> + return i_dev->init(i_dev); >> } >> >> static int __maybe_unused i2c_dw_pci_resume(struct device *dev) >> @@ -228,14 +244,19 @@ static int __maybe_unused i2c_dw_pci_resume(struct device *dev) >> struct dw_i2c_dev *i_dev = dev_get_drvdata(dev); >> int ret; >> >> - ret = i_dev->init(i_dev); >> + ret = i2c_dw_pci_runtime_resume(dev); >> + >> + i2c_lock_bus(&i_dev->adapter, I2C_LOCK_ROOT_ADAPTER); >> i_dev->suspended = false; >> + i2c_unlock_bus(&i_dev->adapter, I2C_LOCK_ROOT_ADAPTER); >> >> return ret; >> } >> >> -static UNIVERSAL_DEV_PM_OPS(i2c_dw_pm_ops, i2c_dw_pci_suspend, >> - i2c_dw_pci_resume, NULL); >> +static const struct dev_pm_ops i2c_dw_pm_ops = { >> + SET_SYSTEM_SLEEP_PM_OPS(i2c_dw_pci_suspend, i2c_dw_pci_resume) >> + SET_RUNTIME_PM_OPS(i2c_dw_pci_runtime_suspend, i2c_dw_pci_runtime_resume, NULL) >> +}; >> >> static int i2c_dw_pci_probe(struct pci_dev *pdev, >> const struct pci_device_id *id) >> diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c >> index 2bd81abc86f6..8e45f65bab73 100644 >> --- a/drivers/i2c/busses/i2c-designware-platdrv.c >> +++ b/drivers/i2c/busses/i2c-designware-platdrv.c >> @@ -368,12 +368,10 @@ static void dw_i2c_plat_complete(struct device *dev) >> #endif >> >> #ifdef CONFIG_PM >> -static int dw_i2c_plat_suspend(struct device *dev) >> +static int dw_i2c_plat_runtime_suspend(struct device *dev) >> { >> struct dw_i2c_dev *i_dev = dev_get_drvdata(dev); >> >> - i_dev->suspended = true; >> - >> if (i_dev->shared_with_punit) >> return 0; >> >> @@ -383,7 +381,18 @@ static int dw_i2c_plat_suspend(struct device *dev) >> return 0; >> } >> >> -static int dw_i2c_plat_resume(struct device *dev) >> +static int dw_i2c_plat_suspend(struct device *dev) >> +{ >> + struct dw_i2c_dev *i_dev = dev_get_drvdata(dev); >> + >> + i2c_lock_bus(&i_dev->adapter, I2C_LOCK_ROOT_ADAPTER); >> + i_dev->suspended = true; >> + i2c_unlock_bus(&i_dev->adapter, I2C_LOCK_ROOT_ADAPTER); >> + >> + return dw_i2c_plat_runtime_suspend(dev); >> +} >> + >> +static int dw_i2c_plat_runtime_resume(struct device *dev) >> { >> struct dw_i2c_dev *i_dev = dev_get_drvdata(dev); >> >> @@ -391,7 +400,19 @@ static int dw_i2c_plat_resume(struct device *dev) >> i2c_dw_prepare_clk(i_dev, true); >> >> i_dev->init(i_dev); >> + >> + return 0; >> +} >> + >> +static int dw_i2c_plat_resume(struct device *dev) >> +{ >> + struct dw_i2c_dev *i_dev = dev_get_drvdata(dev); >> + >> + dw_i2c_plat_runtime_resume(dev); >> + >> + i2c_lock_bus(&i_dev->adapter, I2C_LOCK_ROOT_ADAPTER); >> i_dev->suspended = false; >> + i2c_unlock_bus(&i_dev->adapter, I2C_LOCK_ROOT_ADAPTER); >> >> return 0; >> } >> @@ -400,7 +421,7 @@ static const struct dev_pm_ops dw_i2c_dev_pm_ops = { >> .prepare = dw_i2c_plat_prepare, >> .complete = dw_i2c_plat_complete, >> SET_LATE_SYSTEM_SLEEP_PM_OPS(dw_i2c_plat_suspend, dw_i2c_plat_resume) >> - SET_RUNTIME_PM_OPS(dw_i2c_plat_suspend, dw_i2c_plat_resume, NULL) >> + SET_RUNTIME_PM_OPS(dw_i2c_plat_runtime_suspend, dw_i2c_plat_runtime_resume, NULL) >> }; >> >> #define DW_I2C_DEV_PMOPS (&dw_i2c_dev_pm_ops) >> -- >> 2.35.1 >> >
On 2/23/22 17:15, Hans de Goede wrote: > Hi Andy, > > On 2/23/22 15:52, Andy Shevchenko wrote: >> On Wed, Feb 23, 2022 at 02:48:38PM +0100, Hans de Goede wrote: >>> Lock the adapter while setting the suspended flag, to ensure that other >>> locked code always sees the change immediately, rather then possibly using >>> a stale value. >>> >>> This involves splitting the suspend/resume callbacks into separate runtime >>> and normal suspend/resume calls. This is necessary because i2c_dw_xfer() >>> will get called by the i2c-core with the adapter locked and it in turn >>> calls the runtime-resume callback through pm_runtime_get_sync(). >>> >>> So the runtime versions of the suspend/resume callbacks cannot take >>> the adapter-lock. Note this patch simply makes the runtime suspend/resume >>> callbacks not deal with the suspended flag at all. During runtime the >>> pm_runtime_get_sync() from i2c_dw_xfer() will always ensure that the >>> adapter is resumed when necessary. >>> >>> The suspended flag check is only necessary to check proper suspend/resume >>> ordering during normal suspend/resume which makes the pm_runtime_get_sync() >>> call a no-op. >> >> Both patches look good to me and seems like a nice clean up. Not sure if the >> first one should be backported (and hence have a Fixes tag). >> >> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > > Thank you for the review. As for adding a Fixes: tag, this was inspired > by an actual bug-report, but it did not help in fixing the bug, so I left > the fixes tag out. > > If you or Wolfram still want to add a Fixes tag, then it should be: > > Fixes: 275154155538 ("i2c: designware: Do not allow i2c_dw_xfer() calls while suspended") > Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
diff --git a/drivers/i2c/busses/i2c-designware-pcidrv.c b/drivers/i2c/busses/i2c-designware-pcidrv.c index ef4250f8852b..9553d7075223 100644 --- a/drivers/i2c/busses/i2c-designware-pcidrv.c +++ b/drivers/i2c/busses/i2c-designware-pcidrv.c @@ -213,14 +213,30 @@ static struct dw_pci_controller dw_pci_controllers[] = { }, }; +static int __maybe_unused i2c_dw_pci_runtime_suspend(struct device *dev) +{ + struct dw_i2c_dev *i_dev = dev_get_drvdata(dev); + + i_dev->disable(i_dev); + return 0; +} + static int __maybe_unused i2c_dw_pci_suspend(struct device *dev) { struct dw_i2c_dev *i_dev = dev_get_drvdata(dev); + i2c_lock_bus(&i_dev->adapter, I2C_LOCK_ROOT_ADAPTER); i_dev->suspended = true; - i_dev->disable(i_dev); + i2c_unlock_bus(&i_dev->adapter, I2C_LOCK_ROOT_ADAPTER); - return 0; + return i2c_dw_pci_runtime_suspend(dev); +} + +static int __maybe_unused i2c_dw_pci_runtime_resume(struct device *dev) +{ + struct dw_i2c_dev *i_dev = dev_get_drvdata(dev); + + return i_dev->init(i_dev); } static int __maybe_unused i2c_dw_pci_resume(struct device *dev) @@ -228,14 +244,19 @@ static int __maybe_unused i2c_dw_pci_resume(struct device *dev) struct dw_i2c_dev *i_dev = dev_get_drvdata(dev); int ret; - ret = i_dev->init(i_dev); + ret = i2c_dw_pci_runtime_resume(dev); + + i2c_lock_bus(&i_dev->adapter, I2C_LOCK_ROOT_ADAPTER); i_dev->suspended = false; + i2c_unlock_bus(&i_dev->adapter, I2C_LOCK_ROOT_ADAPTER); return ret; } -static UNIVERSAL_DEV_PM_OPS(i2c_dw_pm_ops, i2c_dw_pci_suspend, - i2c_dw_pci_resume, NULL); +static const struct dev_pm_ops i2c_dw_pm_ops = { + SET_SYSTEM_SLEEP_PM_OPS(i2c_dw_pci_suspend, i2c_dw_pci_resume) + SET_RUNTIME_PM_OPS(i2c_dw_pci_runtime_suspend, i2c_dw_pci_runtime_resume, NULL) +}; static int i2c_dw_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c index 2bd81abc86f6..8e45f65bab73 100644 --- a/drivers/i2c/busses/i2c-designware-platdrv.c +++ b/drivers/i2c/busses/i2c-designware-platdrv.c @@ -368,12 +368,10 @@ static void dw_i2c_plat_complete(struct device *dev) #endif #ifdef CONFIG_PM -static int dw_i2c_plat_suspend(struct device *dev) +static int dw_i2c_plat_runtime_suspend(struct device *dev) { struct dw_i2c_dev *i_dev = dev_get_drvdata(dev); - i_dev->suspended = true; - if (i_dev->shared_with_punit) return 0; @@ -383,7 +381,18 @@ static int dw_i2c_plat_suspend(struct device *dev) return 0; } -static int dw_i2c_plat_resume(struct device *dev) +static int dw_i2c_plat_suspend(struct device *dev) +{ + struct dw_i2c_dev *i_dev = dev_get_drvdata(dev); + + i2c_lock_bus(&i_dev->adapter, I2C_LOCK_ROOT_ADAPTER); + i_dev->suspended = true; + i2c_unlock_bus(&i_dev->adapter, I2C_LOCK_ROOT_ADAPTER); + + return dw_i2c_plat_runtime_suspend(dev); +} + +static int dw_i2c_plat_runtime_resume(struct device *dev) { struct dw_i2c_dev *i_dev = dev_get_drvdata(dev); @@ -391,7 +400,19 @@ static int dw_i2c_plat_resume(struct device *dev) i2c_dw_prepare_clk(i_dev, true); i_dev->init(i_dev); + + return 0; +} + +static int dw_i2c_plat_resume(struct device *dev) +{ + struct dw_i2c_dev *i_dev = dev_get_drvdata(dev); + + dw_i2c_plat_runtime_resume(dev); + + i2c_lock_bus(&i_dev->adapter, I2C_LOCK_ROOT_ADAPTER); i_dev->suspended = false; + i2c_unlock_bus(&i_dev->adapter, I2C_LOCK_ROOT_ADAPTER); return 0; } @@ -400,7 +421,7 @@ static const struct dev_pm_ops dw_i2c_dev_pm_ops = { .prepare = dw_i2c_plat_prepare, .complete = dw_i2c_plat_complete, SET_LATE_SYSTEM_SLEEP_PM_OPS(dw_i2c_plat_suspend, dw_i2c_plat_resume) - SET_RUNTIME_PM_OPS(dw_i2c_plat_suspend, dw_i2c_plat_resume, NULL) + SET_RUNTIME_PM_OPS(dw_i2c_plat_runtime_suspend, dw_i2c_plat_runtime_resume, NULL) }; #define DW_I2C_DEV_PMOPS (&dw_i2c_dev_pm_ops)
Lock the adapter while setting the suspended flag, to ensure that other locked code always sees the change immediately, rather then possibly using a stale value. This involves splitting the suspend/resume callbacks into separate runtime and normal suspend/resume calls. This is necessary because i2c_dw_xfer() will get called by the i2c-core with the adapter locked and it in turn calls the runtime-resume callback through pm_runtime_get_sync(). So the runtime versions of the suspend/resume callbacks cannot take the adapter-lock. Note this patch simply makes the runtime suspend/resume callbacks not deal with the suspended flag at all. During runtime the pm_runtime_get_sync() from i2c_dw_xfer() will always ensure that the adapter is resumed when necessary. The suspended flag check is only necessary to check proper suspend/resume ordering during normal suspend/resume which makes the pm_runtime_get_sync() call a no-op. Signed-off-by: Hans de Goede <hdegoede@redhat.com> --- drivers/i2c/busses/i2c-designware-pcidrv.c | 31 +++++++++++++++++---- drivers/i2c/busses/i2c-designware-platdrv.c | 31 +++++++++++++++++---- 2 files changed, 52 insertions(+), 10 deletions(-)