On Mon, Feb 28, 2022 at 08:19:41PM -0800, David E. Box wrote: > From: Michael Bottini <michael.a.bottini@xxxxxxxxxxxxxxx> > > Add pci_enable_default_link_state() to allow devices to change the default > BIOS configured states. Clears the BIOS default settings then sets the new > states and reconfigures the link under the semaphore. Also add > PCIE_LINK_STATE_ALL macro for convenience for callers that want to enable > all link states. > > Signed-off-by: Michael Bottini <michael.a.bottini@xxxxxxxxxxxxxxx> > Signed-off-by: David E. Box <david.e.box@xxxxxxxxxxxxxxx> > --- > V6 > - No change > V5 > - Rename to pci_enable_default_link_state and model after > pci_disable_link_state() as suggested by Bjorn. > - Add helper PCIE_LINK_STATE_ALL which sets bits for all links states and > clock pm. > - Clarify commit language to indicate the function changes the default > link states (not ASPM policy). > V4 > - Refactor vmd_enable_apsm() to exit early, making the lines shorter > and more readable. Suggested by Christoph. > V3 > - No changes > V2 > - Use return status to print pci_info message if ASPM cannot be enabled. > - Add missing static declaration, caught by lkp@xxxxxxxxx > > > drivers/pci/pcie/aspm.c | 54 +++++++++++++++++++++++++++++++++++++++++ > include/linux/pci.h | 7 ++++++ > 2 files changed, 61 insertions(+) This requires Bjorn's ACK, delegated to him in patchwork. Lorenzo > diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c > index a96b7424c9bc..b2752851b1ba 100644 > --- a/drivers/pci/pcie/aspm.c > +++ b/drivers/pci/pcie/aspm.c > @@ -1132,6 +1132,60 @@ int pci_disable_link_state(struct pci_dev *pdev, int state) > } > EXPORT_SYMBOL(pci_disable_link_state); > > +/** > + * pci_enable_default_link_state - Clears and sets the default device link state > + * so that the link may be allowed to enter the specified states. Note that > + * if the BIOS didn't grant ASPM control to the OS, this does nothing because > + * we can't touch the LNKCTL register. Also note that this does not enable > + * states disabled by pci_disable_link_state(). Returns 0 or a negative errno. > + * > + * @pdev: PCI device > + * @state: Mask of ASPM link states to enable > + */ > +int pci_enable_default_link_state(struct pci_dev *pdev, int state) > +{ > + struct pcie_link_state *link = pcie_aspm_get_link(pdev); > + > + if (!link) > + return -EINVAL; > + /* > + * A driver requested that ASPM be enabled on this device, but > + * if we don't have permission to manage ASPM (e.g., on ACPI > + * systems we have to observe the FADT ACPI_FADT_NO_ASPM bit and > + * the _OSC method), we can't honor that request. > + */ > + if (aspm_disabled) { > + pci_warn(pdev, "can't override BIOS ASPM; OS doesn't have ASPM control\n"); > + return -EPERM; > + } > + > + down_read(&pci_bus_sem); > + mutex_lock(&aspm_lock); > + link->aspm_default = 0; > + if (state & PCIE_LINK_STATE_L0S) > + link->aspm_default |= ASPM_STATE_L0S; > + if (state & PCIE_LINK_STATE_L1) > + /* L1 PM substates require L1 */ > + link->aspm_default |= ASPM_STATE_L1 | ASPM_STATE_L1SS; > + if (state & PCIE_LINK_STATE_L1_1) > + link->aspm_default |= ASPM_STATE_L1_1; > + if (state & PCIE_LINK_STATE_L1_2) > + link->aspm_default |= ASPM_STATE_L1_2; > + if (state & PCIE_LINK_STATE_L1_1_PCIPM) > + link->aspm_default |= ASPM_STATE_L1_1_PCIPM; > + if (state & PCIE_LINK_STATE_L1_2_PCIPM) > + link->aspm_default |= ASPM_STATE_L1_2_PCIPM; > + pcie_config_aspm_link(link, policy_to_aspm_state(link)); > + > + link->clkpm_default = (state & PCIE_LINK_STATE_CLKPM) ? 1 : 0; > + pcie_set_clkpm(link, policy_to_clkpm_state(link)); > + mutex_unlock(&aspm_lock); > + up_read(&pci_bus_sem); > + > + return 0; > +} > +EXPORT_SYMBOL(pci_enable_default_link_state); > + > static int pcie_aspm_set_policy(const char *val, > const struct kernel_param *kp) > { > diff --git a/include/linux/pci.h b/include/linux/pci.h > index 8253a5413d7c..fd710afe0209 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -1641,10 +1641,15 @@ extern bool pcie_ports_native; > #define PCIE_LINK_STATE_L1_2 BIT(4) > #define PCIE_LINK_STATE_L1_1_PCIPM BIT(5) > #define PCIE_LINK_STATE_L1_2_PCIPM BIT(6) > +#define PCIE_LINK_STATE_ALL (PCIE_LINK_STATE_L0S | PCIE_LINK_STATE_L1 |\ > + PCIE_LINK_STATE_CLKPM | PCIE_LINK_STATE_L1_1 |\ > + PCIE_LINK_STATE_L1_2 | PCIE_LINK_STATE_L1_1_PCIPM |\ > + PCIE_LINK_STATE_L1_2_PCIPM) > > #ifdef CONFIG_PCIEASPM > int pci_disable_link_state(struct pci_dev *pdev, int state); > int pci_disable_link_state_locked(struct pci_dev *pdev, int state); > +int pci_enable_default_link_state(struct pci_dev *pdev, int state); > void pcie_no_aspm(void); > bool pcie_aspm_support_enabled(void); > bool pcie_aspm_enabled(struct pci_dev *pdev); > @@ -1653,6 +1658,8 @@ static inline int pci_disable_link_state(struct pci_dev *pdev, int state) > { return 0; } > static inline int pci_disable_link_state_locked(struct pci_dev *pdev, int state) > { return 0; } > +static inline int pci_enable_default_link_state(struct pci_dev *pdev, int state) > +{ return 0; } > static inline void pcie_no_aspm(void) { } > static inline bool pcie_aspm_support_enabled(void) { return false; } > static inline bool pcie_aspm_enabled(struct pci_dev *pdev) { return false; } > -- > 2.25.1 > >