From: Krishna Chaitanya Chundru <krishna.chundru@xxxxxxxxxxxxxxxx> Date: Sat, 12 Apr 2025 07:19:56 +0530 Introduce a common API to check if the PCIe link is active, replacing duplicate code in multiple locations. Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@xxxxxxxxxxxxxxxx> Signed-off-by: Shawn Anastasio <sanastasio@xxxxxxxxxxxxxxxxxxxxx> --- (Resent since git-send-email failed to detect the Subject field from the patch file previously -- apologies!) This is an updated patch pulled from Krishna's v5 series: https://patchwork.kernel.org/project/linux-pci/list/?series=952665 The following changes to Krishna's v5 were made by me: - Revert pcie_link_is_active return type back to int per Lukas' review comments - Handle non-zero error returns at call site of the new function in pci.c/pci_bridge_wait_for_secondary_bus drivers/pci/hotplug/pciehp.h | 1 - drivers/pci/hotplug/pciehp_ctrl.c | 2 +- drivers/pci/hotplug/pciehp_hpc.c | 33 +++---------------------------- drivers/pci/pci.c | 26 +++++++++++++++++++++--- include/linux/pci.h | 4 ++++ 5 files changed, 31 insertions(+), 35 deletions(-) diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h index 273dd8c66f4e..acef728530e3 100644 --- a/drivers/pci/hotplug/pciehp.h +++ b/drivers/pci/hotplug/pciehp.h @@ -186,7 +186,6 @@ int pciehp_query_power_fault(struct controller *ctrl); int pciehp_card_present(struct controller *ctrl); int pciehp_card_present_or_link_active(struct controller *ctrl); int pciehp_check_link_status(struct controller *ctrl); -int pciehp_check_link_active(struct controller *ctrl); void pciehp_release_ctrl(struct controller *ctrl); int pciehp_sysfs_enable_slot(struct hotplug_slot *hotplug_slot); diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pciehp_ctrl.c index d603a7aa7483..4bb58ba1c766 100644 --- a/drivers/pci/hotplug/pciehp_ctrl.c +++ b/drivers/pci/hotplug/pciehp_ctrl.c @@ -260,7 +260,7 @@ void pciehp_handle_presence_or_link_change(struct controller *ctrl, u32 events) /* Turn the slot on if it's occupied or link is up */ mutex_lock(&ctrl->state_lock); present = pciehp_card_present(ctrl); - link_active = pciehp_check_link_active(ctrl); + link_active = pcie_link_is_active(ctrl->pcie->port); if (present <= 0 && link_active <= 0) { if (ctrl->state == BLINKINGON_STATE) { ctrl->state = OFF_STATE; diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c index 8a09fb6083e2..278bc21d531d 100644 --- a/drivers/pci/hotplug/pciehp_hpc.c +++ b/drivers/pci/hotplug/pciehp_hpc.c @@ -221,33 +221,6 @@ static void pcie_write_cmd_nowait(struct controller *ctrl, u16 cmd, u16 mask) pcie_do_write_cmd(ctrl, cmd, mask, false); } -/** - * pciehp_check_link_active() - Is the link active - * @ctrl: PCIe hotplug controller - * - * Check whether the downstream link is currently active. Note it is - * possible that the card is removed immediately after this so the - * caller may need to take it into account. - * - * If the hotplug controller itself is not available anymore returns - * %-ENODEV. - */ -int pciehp_check_link_active(struct controller *ctrl) -{ - struct pci_dev *pdev = ctrl_dev(ctrl); - u16 lnk_status; - int ret; - - ret = pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status); - if (ret == PCIBIOS_DEVICE_NOT_FOUND || PCI_POSSIBLE_ERROR(lnk_status)) - return -ENODEV; - - ret = !!(lnk_status & PCI_EXP_LNKSTA_DLLLA); - ctrl_dbg(ctrl, "%s: lnk_status = %x\n", __func__, lnk_status); - - return ret; -} - static bool pci_bus_check_dev(struct pci_bus *bus, int devfn) { u32 l; @@ -467,7 +440,7 @@ int pciehp_card_present_or_link_active(struct controller *ctrl) if (ret) return ret; - return pciehp_check_link_active(ctrl); + return pcie_link_is_active(ctrl_dev(ctrl)); } int pciehp_query_power_fault(struct controller *ctrl) @@ -584,7 +557,7 @@ static void pciehp_ignore_dpc_link_change(struct controller *ctrl, * Synthesize it to ensure that it is acted on. */ down_read_nested(&ctrl->reset_lock, ctrl->depth); - if (!pciehp_check_link_active(ctrl)) + if (!pcie_link_is_active(ctrl_dev(ctrl))) pciehp_request(ctrl, PCI_EXP_SLTSTA_DLLSC); up_read(&ctrl->reset_lock); } @@ -884,7 +857,7 @@ int pciehp_slot_reset(struct pcie_device *dev) pcie_capability_write_word(dev->port, PCI_EXP_SLTSTA, PCI_EXP_SLTSTA_DLLSC); - if (!pciehp_check_link_active(ctrl)) + if (!pcie_link_is_active(ctrl_dev(ctrl))) pciehp_request(ctrl, PCI_EXP_SLTSTA_DLLSC); return 0; diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index e77d5b53c0ce..3bb8354b14bf 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -4926,7 +4926,6 @@ int pci_bridge_wait_for_secondary_bus(struct pci_dev *dev, char *reset_type) return 0; if (pcie_get_speed_cap(dev) <= PCIE_SPEED_5_0GT) { - u16 status; pci_dbg(dev, "waiting %d ms for downstream link\n", delay); msleep(delay); @@ -4942,8 +4941,7 @@ int pci_bridge_wait_for_secondary_bus(struct pci_dev *dev, char *reset_type) if (!dev->link_active_reporting) return -ENOTTY; - pcie_capability_read_word(dev, PCI_EXP_LNKSTA, &status); - if (!(status & PCI_EXP_LNKSTA_DLLLA)) + if (pcie_link_is_active(dev) <= 0) return -ENOTTY; return pci_dev_wait(child, reset_type, @@ -6247,6 +6245,28 @@ void pcie_print_link_status(struct pci_dev *dev) } EXPORT_SYMBOL(pcie_print_link_status); +/** + * pcie_link_is_active() - Checks if the link is active or not + * @pdev: PCI device to query + * + * Check whether the link is active or not. + * + * Return: link state, or -ENODEV if the config read failes. + */ +int pcie_link_is_active(struct pci_dev *pdev) +{ + u16 lnk_status; + int ret; + + ret = pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status); + if (ret == PCIBIOS_DEVICE_NOT_FOUND || PCI_POSSIBLE_ERROR(lnk_status)) + return -ENODEV; + + pci_dbg(pdev, "lnk_status = %x\n", lnk_status); + return !!(lnk_status & PCI_EXP_LNKSTA_DLLLA); +} +EXPORT_SYMBOL(pcie_link_is_active); + /** * pci_select_bars - Make BAR mask from the type of resource * @dev: the PCI device for which BAR mask is made diff --git a/include/linux/pci.h b/include/linux/pci.h index 51e2bd6405cd..a79a9919320c 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1945,6 +1945,7 @@ pci_release_mem_regions(struct pci_dev *pdev) pci_select_bars(pdev, IORESOURCE_MEM)); } +int pcie_link_is_active(struct pci_dev *dev); #else /* CONFIG_PCI is not enabled */ static inline void pci_set_flags(int flags) { } @@ -2093,6 +2094,9 @@ pci_alloc_irq_vectors(struct pci_dev *dev, unsigned int min_vecs, { return -ENOSPC; } + +static inline bool pcie_link_is_active(struct pci_dev *dev) +{ return false; } #endif /* CONFIG_PCI */ /* Include architecture-dependent settings and functions */ -- 2.30.2
