diff options
| -rw-r--r-- | drivers/pci/hotplug/pci_hotplug_core.c | 69 | ||||
| -rw-r--r-- | drivers/pci/hotplug/pciehp_hpc.c | 35 | ||||
| -rw-r--r-- | drivers/pci/pci.h | 3 | ||||
| -rw-r--r-- | include/linux/pci.h | 8 |
4 files changed, 92 insertions, 23 deletions
diff --git a/drivers/pci/hotplug/pci_hotplug_core.c b/drivers/pci/hotplug/pci_hotplug_core.c index d30f1316c98e..d7fc3bc03964 100644 --- a/drivers/pci/hotplug/pci_hotplug_core.c +++ b/drivers/pci/hotplug/pci_hotplug_core.c @@ -492,6 +492,75 @@ void pci_hp_destroy(struct hotplug_slot *slot) } EXPORT_SYMBOL_GPL(pci_hp_destroy); +static DECLARE_WAIT_QUEUE_HEAD(pci_hp_link_change_wq); + +/** + * pci_hp_ignore_link_change - begin code section causing spurious link changes + * @pdev: PCI hotplug bridge + * + * Mark the beginning of a code section causing spurious link changes on the + * Secondary Bus of @pdev, e.g. as a side effect of a Secondary Bus Reset, + * D3cold transition, firmware update or FPGA reconfiguration. + * + * Hotplug drivers can thus check whether such a code section is executing + * concurrently, await it with pci_hp_spurious_link_change() and ignore the + * resulting link change events. + * + * Must be paired with pci_hp_unignore_link_change(). May be called both + * from the PCI core and from Endpoint drivers. May be called for bridges + * which are not hotplug-capable, in which case it has no effect because + * no hotplug driver is bound to the bridge. + */ +void pci_hp_ignore_link_change(struct pci_dev *pdev) +{ + set_bit(PCI_LINK_CHANGING, &pdev->priv_flags); + smp_mb__after_atomic(); /* pairs with implied barrier of wait_event() */ +} + +/** + * pci_hp_unignore_link_change - end code section causing spurious link changes + * @pdev: PCI hotplug bridge + * + * Mark the end of a code section causing spurious link changes on the + * Secondary Bus of @pdev. Must be paired with pci_hp_ignore_link_change(). + */ +void pci_hp_unignore_link_change(struct pci_dev *pdev) +{ + set_bit(PCI_LINK_CHANGED, &pdev->priv_flags); + mb(); /* ensure pci_hp_spurious_link_change() sees either bit set */ + clear_bit(PCI_LINK_CHANGING, &pdev->priv_flags); + wake_up_all(&pci_hp_link_change_wq); +} + +/** + * pci_hp_spurious_link_change - check for spurious link changes + * @pdev: PCI hotplug bridge + * + * Check whether a code section is executing concurrently which is causing + * spurious link changes on the Secondary Bus of @pdev. Await the end of the + * code section if so. + * + * May be called by hotplug drivers to check whether a link change is spurious + * and can be ignored. + * + * Because a genuine link change may have occurred in-between a spurious link + * change and the invocation of this function, hotplug drivers should perform + * sanity checks such as retrieving the current link state and bringing down + * the slot if the link is down. + * + * Return: %true if such a code section has been executing concurrently, + * otherwise %false. Also return %true if such a code section has not been + * executing concurrently, but at least once since the last invocation of this + * function. + */ +bool pci_hp_spurious_link_change(struct pci_dev *pdev) +{ + wait_event(pci_hp_link_change_wq, + !test_bit(PCI_LINK_CHANGING, &pdev->priv_flags)); + + return test_and_clear_bit(PCI_LINK_CHANGED, &pdev->priv_flags); +} + static int __init pci_hotplug_init(void) { int result; diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c index 388fbed25402..ebd342bda235 100644 --- a/drivers/pci/hotplug/pciehp_hpc.c +++ b/drivers/pci/hotplug/pciehp_hpc.c @@ -592,21 +592,21 @@ bool pciehp_device_replaced(struct controller *ctrl) return false; } -static void pciehp_ignore_dpc_link_change(struct controller *ctrl, - struct pci_dev *pdev, int irq, - u16 ignored_events) +static void pciehp_ignore_link_change(struct controller *ctrl, + struct pci_dev *pdev, int irq, + u16 ignored_events) { /* * Ignore link changes which occurred while waiting for DPC recovery. * Could be several if DPC triggered multiple times consecutively. + * Also ignore link changes caused by Secondary Bus Reset, etc. */ synchronize_hardirq(irq); atomic_and(~ignored_events, &ctrl->pending_events); if (pciehp_poll_mode) pcie_capability_write_word(pdev, PCI_EXP_SLTSTA, ignored_events); - ctrl_info(ctrl, "Slot(%s): Link Down/Up ignored (recovered by DPC)\n", - slot_name(ctrl)); + ctrl_info(ctrl, "Slot(%s): Link Down/Up ignored\n", slot_name(ctrl)); /* * If the link is unexpectedly down after successful recovery, @@ -762,9 +762,11 @@ static irqreturn_t pciehp_ist(int irq, void *dev_id) /* * Ignore Link Down/Up events caused by Downstream Port Containment - * if recovery from the error succeeded. + * if recovery succeeded, or caused by Secondary Bus Reset, + * suspend to D3cold, firmware update, FPGA reconfiguration, etc. */ - if ((events & PCI_EXP_SLTSTA_DLLSC) && pci_dpc_recovered(pdev) && + if ((events & (PCI_EXP_SLTSTA_PDC | PCI_EXP_SLTSTA_DLLSC)) && + (pci_dpc_recovered(pdev) || pci_hp_spurious_link_change(pdev)) && ctrl->state == ON_STATE) { u16 ignored_events = PCI_EXP_SLTSTA_DLLSC; @@ -772,7 +774,7 @@ static irqreturn_t pciehp_ist(int irq, void *dev_id) ignored_events |= events & PCI_EXP_SLTSTA_PDC; events &= ~ignored_events; - pciehp_ignore_dpc_link_change(ctrl, pdev, irq, ignored_events); + pciehp_ignore_link_change(ctrl, pdev, irq, ignored_events); } /* @@ -937,7 +939,6 @@ int pciehp_reset_slot(struct hotplug_slot *hotplug_slot, bool probe) { struct controller *ctrl = to_ctrl(hotplug_slot); struct pci_dev *pdev = ctrl_dev(ctrl); - u16 stat_mask = 0, ctrl_mask = 0; int rc; if (probe) @@ -945,23 +946,11 @@ int pciehp_reset_slot(struct hotplug_slot *hotplug_slot, bool probe) down_write_nested(&ctrl->reset_lock, ctrl->depth); - if (!ATTN_BUTTN(ctrl)) { - ctrl_mask |= PCI_EXP_SLTCTL_PDCE; - stat_mask |= PCI_EXP_SLTSTA_PDC; - } - ctrl_mask |= PCI_EXP_SLTCTL_DLLSCE; - stat_mask |= PCI_EXP_SLTSTA_DLLSC; - - pcie_write_cmd(ctrl, 0, ctrl_mask); - ctrl_dbg(ctrl, "%s: SLOTCTRL %x write cmd %x\n", __func__, - pci_pcie_cap(ctrl->pcie->port) + PCI_EXP_SLTCTL, 0); + pci_hp_ignore_link_change(pdev); rc = pci_bridge_secondary_bus_reset(ctrl->pcie->port); - pcie_capability_write_word(pdev, PCI_EXP_SLTSTA, stat_mask); - pcie_write_cmd_nowait(ctrl, ctrl_mask, ctrl_mask); - ctrl_dbg(ctrl, "%s: SLOTCTRL %x write cmd %x\n", __func__, - pci_pcie_cap(ctrl->pcie->port) + PCI_EXP_SLTCTL, ctrl_mask); + pci_hp_unignore_link_change(pdev); up_write(&ctrl->reset_lock); return rc; diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index b81e99cd4b62..7db798bdcaaa 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -227,6 +227,7 @@ static inline int pci_proc_detach_bus(struct pci_bus *bus) { return 0; } /* Functions for PCI Hotplug drivers to use */ int pci_hp_add_bridge(struct pci_dev *dev); +bool pci_hp_spurious_link_change(struct pci_dev *pdev); #if defined(CONFIG_SYSFS) && defined(HAVE_PCI_LEGACY) void pci_create_legacy_files(struct pci_bus *bus); @@ -557,6 +558,8 @@ static inline int pci_dev_set_disconnected(struct pci_dev *dev, void *unused) #define PCI_DPC_RECOVERED 1 #define PCI_DPC_RECOVERING 2 #define PCI_DEV_REMOVED 3 +#define PCI_LINK_CHANGED 4 +#define PCI_LINK_CHANGING 5 static inline void pci_dev_assign_added(struct pci_dev *dev) { diff --git a/include/linux/pci.h b/include/linux/pci.h index 0e8e3fd77e96..833b54f3ce6d 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1848,6 +1848,14 @@ static inline bool pcie_aspm_support_enabled(void) { return false; } static inline bool pcie_aspm_enabled(struct pci_dev *pdev) { return false; } #endif +#ifdef CONFIG_HOTPLUG_PCI +void pci_hp_ignore_link_change(struct pci_dev *pdev); +void pci_hp_unignore_link_change(struct pci_dev *pdev); +#else +static inline void pci_hp_ignore_link_change(struct pci_dev *pdev) { } +static inline void pci_hp_unignore_link_change(struct pci_dev *pdev) { } +#endif + #ifdef CONFIG_PCIEAER bool pci_aer_available(void); #else |