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Date: Mon, 28 Feb 2022 20:19:41 -0800 From: "David E. Box" <david.e.box@...ux.intel.com> To: nirmal.patel@...ux.intel.com, jonathan.derrick@...ux.dev, lorenzo.pieralisi@....com, hch@...radead.org, kw@...ux.com, robh@...nel.org, bhelgaas@...gle.com, david.e.box@...ux.intel.com, michael.a.bottini@...ux.intel.com, rafael@...nel.org, me@...ityamohan.in Cc: linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org Subject: [PATCH V6 1/3] PCI/ASPM: Add pci_enable_default_link_state() From: Michael Bottini <michael.a.bottini@...ux.intel.com> 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@...ux.intel.com> Signed-off-by: David E. Box <david.e.box@...ux.intel.com> --- 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@...el.com drivers/pci/pcie/aspm.c | 54 +++++++++++++++++++++++++++++++++++++++++ include/linux/pci.h | 7 ++++++ 2 files changed, 61 insertions(+) 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
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