| Submitter | Rafael Wysocki |
|---|---|
| Date | 2009-10-08 22:52:48 |
| Message ID | <200910090052.48493.rjw@sisk.pl> |
| Download | mbox | patch |
| Permalink | /patch/52615/ |
| State | Superseded |
| Headers | show |
Comments
On Thursday 08 October 2009 04:52:48 pm Rafael J. Wysocki wrote: > From: Rafael J. Wysocki <rjw@sisk.pl> > > Add function pci_check_pme_status() that will check the PME status > bit of given device and clear it along with the PME enable bit. It > will be necessary for PCI run-time power management. > > Based on a patch from Shaohua Li <shaohua.li@intel.com> > > Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> > --- > drivers/pci/pci.c | 35 +++++++++++++++++++++++++++++++++++ > drivers/pci/pci.h | 1 + > 2 files changed, 36 insertions(+) > > Index: linux-2.6/drivers/pci/pci.h > =================================================================== > --- linux-2.6.orig/drivers/pci/pci.h > +++ linux-2.6/drivers/pci/pci.h > @@ -49,6 +49,7 @@ struct pci_platform_pm_ops { > extern int pci_set_platform_pm(struct pci_platform_pm_ops *ops); > extern void pci_update_current_state(struct pci_dev *dev, pci_power_t state); > extern void pci_disable_enabled_device(struct pci_dev *dev); > +extern bool pci_check_pme_status(struct pci_dev *dev); > extern void pci_pm_init(struct pci_dev *dev); > extern void platform_pci_wakeup_init(struct pci_dev *dev); > extern void pci_allocate_cap_save_buffers(struct pci_dev *dev); > Index: linux-2.6/drivers/pci/pci.c > =================================================================== > --- linux-2.6.orig/drivers/pci/pci.c > +++ linux-2.6/drivers/pci/pci.c > @@ -1167,6 +1167,41 @@ int pci_set_pcie_reset_state(struct pci_ > } > > /** > + * pci_check_pme_status - Check if given device has generated PME. > + * @dev: Device to check. > + * > + * Check the PME status of the device, clear PME status and PME enable. Return > + * 'true' if PME has been generated by the device (and hasn't been spurious) or > + * 'false' otherwise. This comment confuses me because it implies that we always clear PME enable, but that's not what the code does. If PME_STATUS is not asserted, the code doesn't write anything. > + */ > +bool pci_check_pme_status(struct pci_dev *dev) > +{ > + int pmcsr_pos; > + u16 pmcsr; > + bool ret = false; > + > + if (!dev->pm_cap) > + return false; > + > + pmcsr_pos = dev->pm_cap + PCI_PM_CTRL; > + /* clear PME status and disable PME to avoid interrupt flood */ > + pci_read_config_word(dev, pmcsr_pos, &pmcsr); > + if (!(pmcsr & PCI_PM_CTRL_PME_STATUS)) > + return false; > + > + pmcsr |= PCI_PM_CTRL_PME_STATUS; > + /* Ignore spurious PME or clear PME enable if it's not spurious. */ > + if (pmcsr & PCI_PM_CTRL_PME_ENABLE) { > + pmcsr &= ~PCI_PM_CTRL_PME_ENABLE; > + ret = true; > + } > + > + pci_write_config_word(dev, pmcsr_pos, pmcsr); I can't tell whether the comment or the code is what was intended, but I think the following would be a clearer way to implement the comment: pci_read_config_word(..., &pmcsr); pci_write_config_word(..., (pmcsr | STATUS) & ~ENABLE); if ((pmcsr & ENABLE) && (pmcsr & STATUS)) return true; return false; Bjorn > + > + return ret; > +} > + > +/** > * pci_pme_capable - check the capability of PCI device to generate PME# > * @dev: PCI device to handle. > * @state: PCI state from which device will issue PME#. > -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Friday 09 October 2009, Bjorn Helgaas wrote: > On Thursday 08 October 2009 04:52:48 pm Rafael J. Wysocki wrote: > > From: Rafael J. Wysocki <rjw@sisk.pl> > > > > Add function pci_check_pme_status() that will check the PME status > > bit of given device and clear it along with the PME enable bit. It > > will be necessary for PCI run-time power management. > > > > Based on a patch from Shaohua Li <shaohua.li@intel.com> > > > > Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> > > --- > > drivers/pci/pci.c | 35 +++++++++++++++++++++++++++++++++++ > > drivers/pci/pci.h | 1 + > > 2 files changed, 36 insertions(+) > > > > Index: linux-2.6/drivers/pci/pci.h > > =================================================================== > > --- linux-2.6.orig/drivers/pci/pci.h > > +++ linux-2.6/drivers/pci/pci.h > > @@ -49,6 +49,7 @@ struct pci_platform_pm_ops { > > extern int pci_set_platform_pm(struct pci_platform_pm_ops *ops); > > extern void pci_update_current_state(struct pci_dev *dev, pci_power_t state); > > extern void pci_disable_enabled_device(struct pci_dev *dev); > > +extern bool pci_check_pme_status(struct pci_dev *dev); > > extern void pci_pm_init(struct pci_dev *dev); > > extern void platform_pci_wakeup_init(struct pci_dev *dev); > > extern void pci_allocate_cap_save_buffers(struct pci_dev *dev); > > Index: linux-2.6/drivers/pci/pci.c > > =================================================================== > > --- linux-2.6.orig/drivers/pci/pci.c > > +++ linux-2.6/drivers/pci/pci.c > > @@ -1167,6 +1167,41 @@ int pci_set_pcie_reset_state(struct pci_ > > } > > > > /** > > + * pci_check_pme_status - Check if given device has generated PME. > > + * @dev: Device to check. > > + * > > + * Check the PME status of the device, clear PME status and PME enable. Return > > + * 'true' if PME has been generated by the device (and hasn't been spurious) or > > + * 'false' otherwise. > > This comment confuses me because it implies that we always clear PME enable, > but that's not what the code does. If PME_STATUS is not asserted, the code > doesn't write anything. Well, that's a shortcut, perhaps going too far. It should say "clear PME status and PME enable, if the PME status was set". Will fix. > > + */ > > +bool pci_check_pme_status(struct pci_dev *dev) > > +{ > > + int pmcsr_pos; > > + u16 pmcsr; > > + bool ret = false; > > + > > + if (!dev->pm_cap) > > + return false; > > + > > + pmcsr_pos = dev->pm_cap + PCI_PM_CTRL; > > + /* clear PME status and disable PME to avoid interrupt flood */ > > + pci_read_config_word(dev, pmcsr_pos, &pmcsr); > > + if (!(pmcsr & PCI_PM_CTRL_PME_STATUS)) > > + return false; > > + > > + pmcsr |= PCI_PM_CTRL_PME_STATUS; > > + /* Ignore spurious PME or clear PME enable if it's not spurious. */ > > + if (pmcsr & PCI_PM_CTRL_PME_ENABLE) { > > + pmcsr &= ~PCI_PM_CTRL_PME_ENABLE; > > + ret = true; > > + } > > + > > + pci_write_config_word(dev, pmcsr_pos, pmcsr); > > I can't tell whether the comment or the code is what was intended, The code. I'll fix the comment. > but I think the following would be a clearer way to implement the > comment: > > pci_read_config_word(..., &pmcsr); > pci_write_config_word(..., (pmcsr | STATUS) & ~ENABLE); > > if ((pmcsr & ENABLE) && (pmcsr & STATUS)) > return true; > return false; Thanks, Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Patch
Index: linux-2.6/drivers/pci/pci.h =================================================================== --- linux-2.6.orig/drivers/pci/pci.h +++ linux-2.6/drivers/pci/pci.h @@ -49,6 +49,7 @@ struct pci_platform_pm_ops { extern int pci_set_platform_pm(struct pci_platform_pm_ops *ops); extern void pci_update_current_state(struct pci_dev *dev, pci_power_t state); extern void pci_disable_enabled_device(struct pci_dev *dev); +extern bool pci_check_pme_status(struct pci_dev *dev); extern void pci_pm_init(struct pci_dev *dev); extern void platform_pci_wakeup_init(struct pci_dev *dev); extern void pci_allocate_cap_save_buffers(struct pci_dev *dev); Index: linux-2.6/drivers/pci/pci.c =================================================================== --- linux-2.6.orig/drivers/pci/pci.c +++ linux-2.6/drivers/pci/pci.c @@ -1167,6 +1167,41 @@ int pci_set_pcie_reset_state(struct pci_ } /** + * pci_check_pme_status - Check if given device has generated PME. + * @dev: Device to check. + * + * Check the PME status of the device, clear PME status and PME enable. Return + * 'true' if PME has been generated by the device (and hasn't been spurious) or + * 'false' otherwise. + */ +bool pci_check_pme_status(struct pci_dev *dev) +{ + int pmcsr_pos; + u16 pmcsr; + bool ret = false; + + if (!dev->pm_cap) + return false; + + pmcsr_pos = dev->pm_cap + PCI_PM_CTRL; + /* clear PME status and disable PME to avoid interrupt flood */ + pci_read_config_word(dev, pmcsr_pos, &pmcsr); + if (!(pmcsr & PCI_PM_CTRL_PME_STATUS)) + return false; + + pmcsr |= PCI_PM_CTRL_PME_STATUS; + /* Ignore spurious PME or clear PME enable if it's not spurious. */ + if (pmcsr & PCI_PM_CTRL_PME_ENABLE) { + pmcsr &= ~PCI_PM_CTRL_PME_ENABLE; + ret = true; + } + + pci_write_config_word(dev, pmcsr_pos, pmcsr); + + return ret; +} + +/** * pci_pme_capable - check the capability of PCI device to generate PME# * @dev: PCI device to handle. * @state: PCI state from which device will issue PME#.