Reported-by: Sinan Kaya <okaya@xxxxxxxxxx>
Reported-by: Ethan Zhao <haifeng.zhao@xxxxxxxxx>
Reported-by: Sathyanarayanan Kuppuswamy <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Ashok Raj <ashok.raj@xxxxxxxxx>
Cc: Keith Busch <kbusch@xxxxxxxxxx>
---
drivers/pci/hotplug/pciehp_hpc.c | 36 ++++++++++++++++
drivers/pci/pci.h | 4 ++
drivers/pci/pcie/dpc.c | 73 +++++++++++++++++++++++++++++---
3 files changed, 108 insertions(+), 5 deletions(-)
diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index fb3840e222ad..9d06939736c0 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -563,6 +563,32 @@ void pciehp_power_off_slot(struct controller *ctrl)
PCI_EXP_SLTCTL_PWR_OFF);
}
+static void pciehp_ignore_dpc_link_change(struct controller *ctrl,
+ struct pci_dev *pdev, int irq)
+{
+ /*
+ * Ignore link changes which occurred while waiting for DPC recovery.
+ * Could be several if DPC triggered multiple times consecutively.
+ */
+ synchronize_hardirq(irq);
+ atomic_and(~PCI_EXP_SLTSTA_DLLSC, &ctrl->pending_events);
+ if (pciehp_poll_mode)
+ pcie_capability_write_word(pdev, PCI_EXP_SLTSTA,
+ PCI_EXP_SLTSTA_DLLSC);
+ ctrl_info(ctrl, "Slot(%s): Link Down/Up ignored (recovered by DPC)\n",
+ slot_name(ctrl));
+
+ /*
+ * If the link is unexpectedly down after successful recovery,
+ * the corresponding link change may have been ignored above.
+ * Synthesize it to ensure that it is acted on.
+ */
+ down_read(&ctrl->reset_lock);
+ if (!pciehp_check_link_active(ctrl))
+ pciehp_request(ctrl, PCI_EXP_SLTSTA_DLLSC);
+ up_read(&ctrl->reset_lock);
+}
+
static irqreturn_t pciehp_isr(int irq, void *dev_id)
{
struct controller *ctrl = (struct controller *)dev_id;
@@ -706,6 +732,16 @@ static irqreturn_t pciehp_ist(int irq, void *dev_id)
PCI_EXP_SLTCTL_ATTN_IND_ON);
}
+ /*
+ * Ignore Link Down/Up events caused by Downstream Port Containment
+ * if recovery from the error succeeded.
+ */
+ if ((events & PCI_EXP_SLTSTA_DLLSC) && pci_dpc_recovered(pdev) &&
+ ctrl->state == ON_STATE) {
+ events &= ~PCI_EXP_SLTSTA_DLLSC;
+ pciehp_ignore_dpc_link_change(ctrl, pdev, irq);
+ }
+
/*
* Disable requests have higher priority than Presence Detect Changed
* or Data Link Layer State Changed events.
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 9684b468267f..e5ae5e860431 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -392,6 +392,8 @@ static inline bool pci_dev_is_disconnected(const struct pci_dev *dev)
/* pci_dev priv_flags */
#define PCI_DEV_ADDED 0
+#define PCI_DPC_RECOVERED 1
+#define PCI_DPC_RECOVERING 2
static inline void pci_dev_assign_added(struct pci_dev *dev, bool added)
{
@@ -446,10 +448,12 @@ void pci_restore_dpc_state(struct pci_dev *dev);
void pci_dpc_init(struct pci_dev *pdev);
void dpc_process_error(struct pci_dev *pdev);
pci_ers_result_t dpc_reset_link(struct pci_dev *pdev);
+bool pci_dpc_recovered(struct pci_dev *pdev);
#else
static inline void pci_save_dpc_state(struct pci_dev *dev) {}
static inline void pci_restore_dpc_state(struct pci_dev *dev) {}
static inline void pci_dpc_init(struct pci_dev *pdev) {}
+static inline bool pci_dpc_recovered(struct pci_dev *pdev) { return false; }
#endif
#ifdef CONFIG_PCIEPORTBUS
diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index e05aba86a317..da47c448db8a 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -71,6 +71,57 @@ void pci_restore_dpc_state(struct pci_dev *dev)
pci_write_config_word(dev, dev->dpc_cap + PCI_EXP_DPC_CTL, *cap);
}
+static DECLARE_WAIT_QUEUE_HEAD(dpc_completed_waitqueue);
+
+#ifdef CONFIG_HOTPLUG_PCI_PCIE
+static bool dpc_completed(struct pci_dev *pdev)
+{
+ u16 status;
+
+ pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_STATUS, &status);
+ if ((status != 0xffff) && (status & PCI_EXP_DPC_STATUS_TRIGGER))
+ return false;
+
+ if (test_bit(PCI_DPC_RECOVERING, &pdev->priv_flags))
+ return false;
+
+ return true;
+}
+
+/**
+ * pci_dpc_recovered - whether DPC triggered and has recovered successfully
+ * @pdev: PCI device
+ *
+ * Return true if DPC was triggered for @pdev and has recovered successfully.
+ * Wait for recovery if it hasn't completed yet. Called from the PCIe hotplug
+ * driver to recognize and ignore Link Down/Up events caused by DPC.
+ */
+bool pci_dpc_recovered(struct pci_dev *pdev)
+{
+ struct pci_host_bridge *host;
+
+ if (!pdev->dpc_cap)
+ return false;
+
+ /*
+ * Synchronization between hotplug and DPC is not supported
+ * if DPC is owned by firmware and EDR is not enabled.
+ */
+ host = pci_find_host_bridge(pdev->bus);
+ if (!host->native_dpc && !IS_ENABLED(CONFIG_PCIE_EDR))
+ return false;
+
+ /*
+ * Need a timeout in case DPC never completes due to failure of
+ * dpc_wait_rp_inactive().
+ */
+ wait_event_timeout(dpc_completed_waitqueue, dpc_completed(pdev),
+ msecs_to_jiffies(3000));
+
+ return test_and_clear_bit(PCI_DPC_RECOVERED, &pdev->priv_flags);
+}
+#endif /* CONFIG_HOTPLUG_PCI_PCIE */
+
static int dpc_wait_rp_inactive(struct pci_dev *pdev)
{
unsigned long timeout = jiffies + HZ;
@@ -91,8 +142,11 @@ static int dpc_wait_rp_inactive(struct pci_dev *pdev)
pci_ers_result_t dpc_reset_link(struct pci_dev *pdev)
{
+ pci_ers_result_t ret;
u16 cap;
+ set_bit(PCI_DPC_RECOVERING, &pdev->priv_flags);
+
/*
* DPC disables the Link automatically in hardware, so it has
* already been reset by the time we get here.
@@ -106,18 +160,27 @@ pci_ers_result_t dpc_reset_link(struct pci_dev *pdev)
if (!pcie_wait_for_link(pdev, false))
pci_info(pdev, "Data Link Layer Link Active not cleared in 1000 msec\n");
- if (pdev->dpc_rp_extensions && dpc_wait_rp_inactive(pdev))
- return PCI_ERS_RESULT_DISCONNECT;
+ if (pdev->dpc_rp_extensions && dpc_wait_rp_inactive(pdev)) {
+ clear_bit(PCI_DPC_RECOVERED, &pdev->priv_flags);
+ ret = PCI_ERS_RESULT_DISCONNECT;
+ goto out;
+ }
pci_write_config_word(pdev, cap + PCI_EXP_DPC_STATUS,
PCI_EXP_DPC_STATUS_TRIGGER);
if (!pcie_wait_for_link(pdev, true)) {
pci_info(pdev, "Data Link Layer Link Active not set in 1000 msec\n");
- return PCI_ERS_RESULT_DISCONNECT;
+ clear_bit(PCI_DPC_RECOVERED, &pdev->priv_flags);
+ ret = PCI_ERS_RESULT_DISCONNECT;
+ } else {
+ set_bit(PCI_DPC_RECOVERED, &pdev->priv_flags);
+ ret = PCI_ERS_RESULT_RECOVERED;
}
-
- return PCI_ERS_RESULT_RECOVERED;
+out:
+ clear_bit(PCI_DPC_RECOVERING, &pdev->priv_flags);
+ wake_up_all(&dpc_completed_waitqueue);
+ return ret;
}
static void dpc_process_rp_pio_error(struct pci_dev *pdev)
