Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1222 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/eeh_driver.c b/arch/powerpc/kernel/eeh_driver.c
new file mode 100644
index 000000000..f27929517
--- /dev/null
+++ b/arch/powerpc/kernel/eeh_driver.c
@@ -0,0 +1,1222 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * PCI Error Recovery Driver for RPA-compliant PPC64 platform.
+ * Copyright IBM Corp. 2004 2005
+ * Copyright Linas Vepstas <linas@linas.org> 2004, 2005
+ *
+ * Send comments and feedback to Linas Vepstas <linas@austin.ibm.com>
+ */
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/pci_hotplug.h>
+#include <asm/eeh.h>
+#include <asm/eeh_event.h>
+#include <asm/ppc-pci.h>
+#include <asm/pci-bridge.h>
+#include <asm/rtas.h>
+
+struct eeh_rmv_data {
+	struct list_head removed_vf_list;
+	int removed_dev_count;
+};
+
+static int eeh_result_priority(enum pci_ers_result result)
+{
+	switch (result) {
+	case PCI_ERS_RESULT_NONE:
+		return 1;
+	case PCI_ERS_RESULT_NO_AER_DRIVER:
+		return 2;
+	case PCI_ERS_RESULT_RECOVERED:
+		return 3;
+	case PCI_ERS_RESULT_CAN_RECOVER:
+		return 4;
+	case PCI_ERS_RESULT_DISCONNECT:
+		return 5;
+	case PCI_ERS_RESULT_NEED_RESET:
+		return 6;
+	default:
+		WARN_ONCE(1, "Unknown pci_ers_result value: %d\n", (int)result);
+		return 0;
+	}
+};
+
+static const char *pci_ers_result_name(enum pci_ers_result result)
+{
+	switch (result) {
+	case PCI_ERS_RESULT_NONE:
+		return "none";
+	case PCI_ERS_RESULT_CAN_RECOVER:
+		return "can recover";
+	case PCI_ERS_RESULT_NEED_RESET:
+		return "need reset";
+	case PCI_ERS_RESULT_DISCONNECT:
+		return "disconnect";
+	case PCI_ERS_RESULT_RECOVERED:
+		return "recovered";
+	case PCI_ERS_RESULT_NO_AER_DRIVER:
+		return "no AER driver";
+	default:
+		WARN_ONCE(1, "Unknown result type: %d\n", (int)result);
+		return "unknown";
+	}
+};
+
+static enum pci_ers_result pci_ers_merge_result(enum pci_ers_result old,
+						enum pci_ers_result new)
+{
+	if (eeh_result_priority(new) > eeh_result_priority(old))
+		return new;
+	return old;
+}
+
+static bool eeh_dev_removed(struct eeh_dev *edev)
+{
+	return !edev || (edev->mode & EEH_DEV_REMOVED);
+}
+
+static bool eeh_edev_actionable(struct eeh_dev *edev)
+{
+	if (!edev->pdev)
+		return false;
+	if (edev->pdev->error_state == pci_channel_io_perm_failure)
+		return false;
+	if (eeh_dev_removed(edev))
+		return false;
+	if (eeh_pe_passed(edev->pe))
+		return false;
+
+	return true;
+}
+
+/**
+ * eeh_pcid_get - Get the PCI device driver
+ * @pdev: PCI device
+ *
+ * The function is used to retrieve the PCI device driver for
+ * the indicated PCI device. Besides, we will increase the reference
+ * of the PCI device driver to prevent that being unloaded on
+ * the fly. Otherwise, kernel crash would be seen.
+ */
+static inline struct pci_driver *eeh_pcid_get(struct pci_dev *pdev)
+{
+	if (!pdev || !pdev->dev.driver)
+		return NULL;
+
+	if (!try_module_get(pdev->dev.driver->owner))
+		return NULL;
+
+	return to_pci_driver(pdev->dev.driver);
+}
+
+/**
+ * eeh_pcid_put - Dereference on the PCI device driver
+ * @pdev: PCI device
+ *
+ * The function is called to do dereference on the PCI device
+ * driver of the indicated PCI device.
+ */
+static inline void eeh_pcid_put(struct pci_dev *pdev)
+{
+	if (!pdev || !pdev->dev.driver)
+		return;
+
+	module_put(pdev->dev.driver->owner);
+}
+
+/**
+ * eeh_disable_irq - Disable interrupt for the recovering device
+ * @dev: PCI device
+ *
+ * This routine must be called when reporting temporary or permanent
+ * error to the particular PCI device to disable interrupt of that
+ * device. If the device has enabled MSI or MSI-X interrupt, we needn't
+ * do real work because EEH should freeze DMA transfers for those PCI
+ * devices encountering EEH errors, which includes MSI or MSI-X.
+ */
+static void eeh_disable_irq(struct eeh_dev *edev)
+{
+	/* Don't disable MSI and MSI-X interrupts. They are
+	 * effectively disabled by the DMA Stopped state
+	 * when an EEH error occurs.
+	 */
+	if (edev->pdev->msi_enabled || edev->pdev->msix_enabled)
+		return;
+
+	if (!irq_has_action(edev->pdev->irq))
+		return;
+
+	edev->mode |= EEH_DEV_IRQ_DISABLED;
+	disable_irq_nosync(edev->pdev->irq);
+}
+
+/**
+ * eeh_enable_irq - Enable interrupt for the recovering device
+ * @dev: PCI device
+ *
+ * This routine must be called to enable interrupt while failed
+ * device could be resumed.
+ */
+static void eeh_enable_irq(struct eeh_dev *edev)
+{
+	if ((edev->mode) & EEH_DEV_IRQ_DISABLED) {
+		edev->mode &= ~EEH_DEV_IRQ_DISABLED;
+		/*
+		 * FIXME !!!!!
+		 *
+		 * This is just ass backwards. This maze has
+		 * unbalanced irq_enable/disable calls. So instead of
+		 * finding the root cause it works around the warning
+		 * in the irq_enable code by conditionally calling
+		 * into it.
+		 *
+		 * That's just wrong.The warning in the core code is
+		 * there to tell people to fix their asymmetries in
+		 * their own code, not by abusing the core information
+		 * to avoid it.
+		 *
+		 * I so wish that the assymetry would be the other way
+		 * round and a few more irq_disable calls render that
+		 * shit unusable forever.
+		 *
+		 *	tglx
+		 */
+		if (irqd_irq_disabled(irq_get_irq_data(edev->pdev->irq)))
+			enable_irq(edev->pdev->irq);
+	}
+}
+
+static void eeh_dev_save_state(struct eeh_dev *edev, void *userdata)
+{
+	struct pci_dev *pdev;
+
+	if (!edev)
+		return;
+
+	/*
+	 * We cannot access the config space on some adapters.
+	 * Otherwise, it will cause fenced PHB. We don't save
+	 * the content in their config space and will restore
+	 * from the initial config space saved when the EEH
+	 * device is created.
+	 */
+	if (edev->pe && (edev->pe->state & EEH_PE_CFG_RESTRICTED))
+		return;
+
+	pdev = eeh_dev_to_pci_dev(edev);
+	if (!pdev)
+		return;
+
+	pci_save_state(pdev);
+}
+
+static void eeh_set_channel_state(struct eeh_pe *root, pci_channel_state_t s)
+{
+	struct eeh_pe *pe;
+	struct eeh_dev *edev, *tmp;
+
+	eeh_for_each_pe(root, pe)
+		eeh_pe_for_each_dev(pe, edev, tmp)
+			if (eeh_edev_actionable(edev))
+				edev->pdev->error_state = s;
+}
+
+static void eeh_set_irq_state(struct eeh_pe *root, bool enable)
+{
+	struct eeh_pe *pe;
+	struct eeh_dev *edev, *tmp;
+
+	eeh_for_each_pe(root, pe) {
+		eeh_pe_for_each_dev(pe, edev, tmp) {
+			if (!eeh_edev_actionable(edev))
+				continue;
+
+			if (!eeh_pcid_get(edev->pdev))
+				continue;
+
+			if (enable)
+				eeh_enable_irq(edev);
+			else
+				eeh_disable_irq(edev);
+
+			eeh_pcid_put(edev->pdev);
+		}
+	}
+}
+
+typedef enum pci_ers_result (*eeh_report_fn)(struct eeh_dev *,
+					     struct pci_dev *,
+					     struct pci_driver *);
+static void eeh_pe_report_edev(struct eeh_dev *edev, eeh_report_fn fn,
+			       enum pci_ers_result *result)
+{
+	struct pci_dev *pdev;
+	struct pci_driver *driver;
+	enum pci_ers_result new_result;
+
+	pci_lock_rescan_remove();
+	pdev = edev->pdev;
+	if (pdev)
+		get_device(&pdev->dev);
+	pci_unlock_rescan_remove();
+	if (!pdev) {
+		eeh_edev_info(edev, "no device");
+		return;
+	}
+	device_lock(&pdev->dev);
+	if (eeh_edev_actionable(edev)) {
+		driver = eeh_pcid_get(pdev);
+
+		if (!driver)
+			eeh_edev_info(edev, "no driver");
+		else if (!driver->err_handler)
+			eeh_edev_info(edev, "driver not EEH aware");
+		else if (edev->mode & EEH_DEV_NO_HANDLER)
+			eeh_edev_info(edev, "driver bound too late");
+		else {
+			new_result = fn(edev, pdev, driver);
+			eeh_edev_info(edev, "%s driver reports: '%s'",
+				      driver->name,
+				      pci_ers_result_name(new_result));
+			if (result)
+				*result = pci_ers_merge_result(*result,
+							       new_result);
+		}
+		if (driver)
+			eeh_pcid_put(pdev);
+	} else {
+		eeh_edev_info(edev, "not actionable (%d,%d,%d)", !!pdev,
+			      !eeh_dev_removed(edev), !eeh_pe_passed(edev->pe));
+	}
+	device_unlock(&pdev->dev);
+	if (edev->pdev != pdev)
+		eeh_edev_warn(edev, "Device changed during processing!\n");
+	put_device(&pdev->dev);
+}
+
+static void eeh_pe_report(const char *name, struct eeh_pe *root,
+			  eeh_report_fn fn, enum pci_ers_result *result)
+{
+	struct eeh_pe *pe;
+	struct eeh_dev *edev, *tmp;
+
+	pr_info("EEH: Beginning: '%s'\n", name);
+	eeh_for_each_pe(root, pe) eeh_pe_for_each_dev(pe, edev, tmp)
+		eeh_pe_report_edev(edev, fn, result);
+	if (result)
+		pr_info("EEH: Finished:'%s' with aggregate recovery state:'%s'\n",
+			name, pci_ers_result_name(*result));
+	else
+		pr_info("EEH: Finished:'%s'", name);
+}
+
+/**
+ * eeh_report_error - Report pci error to each device driver
+ * @edev: eeh device
+ * @driver: device's PCI driver
+ *
+ * Report an EEH error to each device driver.
+ */
+static enum pci_ers_result eeh_report_error(struct eeh_dev *edev,
+					    struct pci_dev *pdev,
+					    struct pci_driver *driver)
+{
+	enum pci_ers_result rc;
+
+	if (!driver->err_handler->error_detected)
+		return PCI_ERS_RESULT_NONE;
+
+	eeh_edev_info(edev, "Invoking %s->error_detected(IO frozen)",
+		      driver->name);
+	rc = driver->err_handler->error_detected(pdev, pci_channel_io_frozen);
+
+	edev->in_error = true;
+	pci_uevent_ers(pdev, PCI_ERS_RESULT_NONE);
+	return rc;
+}
+
+/**
+ * eeh_report_mmio_enabled - Tell drivers that MMIO has been enabled
+ * @edev: eeh device
+ * @driver: device's PCI driver
+ *
+ * Tells each device driver that IO ports, MMIO and config space I/O
+ * are now enabled.
+ */
+static enum pci_ers_result eeh_report_mmio_enabled(struct eeh_dev *edev,
+						   struct pci_dev *pdev,
+						   struct pci_driver *driver)
+{
+	if (!driver->err_handler->mmio_enabled)
+		return PCI_ERS_RESULT_NONE;
+	eeh_edev_info(edev, "Invoking %s->mmio_enabled()", driver->name);
+	return driver->err_handler->mmio_enabled(pdev);
+}
+
+/**
+ * eeh_report_reset - Tell device that slot has been reset
+ * @edev: eeh device
+ * @driver: device's PCI driver
+ *
+ * This routine must be called while EEH tries to reset particular
+ * PCI device so that the associated PCI device driver could take
+ * some actions, usually to save data the driver needs so that the
+ * driver can work again while the device is recovered.
+ */
+static enum pci_ers_result eeh_report_reset(struct eeh_dev *edev,
+					    struct pci_dev *pdev,
+					    struct pci_driver *driver)
+{
+	if (!driver->err_handler->slot_reset || !edev->in_error)
+		return PCI_ERS_RESULT_NONE;
+	eeh_edev_info(edev, "Invoking %s->slot_reset()", driver->name);
+	return driver->err_handler->slot_reset(pdev);
+}
+
+static void eeh_dev_restore_state(struct eeh_dev *edev, void *userdata)
+{
+	struct pci_dev *pdev;
+
+	if (!edev)
+		return;
+
+	/*
+	 * The content in the config space isn't saved because
+	 * the blocked config space on some adapters. We have
+	 * to restore the initial saved config space when the
+	 * EEH device is created.
+	 */
+	if (edev->pe && (edev->pe->state & EEH_PE_CFG_RESTRICTED)) {
+		if (list_is_last(&edev->entry, &edev->pe->edevs))
+			eeh_pe_restore_bars(edev->pe);
+
+		return;
+	}
+
+	pdev = eeh_dev_to_pci_dev(edev);
+	if (!pdev)
+		return;
+
+	pci_restore_state(pdev);
+}
+
+/**
+ * eeh_report_resume - Tell device to resume normal operations
+ * @edev: eeh device
+ * @driver: device's PCI driver
+ *
+ * This routine must be called to notify the device driver that it
+ * could resume so that the device driver can do some initialization
+ * to make the recovered device work again.
+ */
+static enum pci_ers_result eeh_report_resume(struct eeh_dev *edev,
+					     struct pci_dev *pdev,
+					     struct pci_driver *driver)
+{
+	if (!driver->err_handler->resume || !edev->in_error)
+		return PCI_ERS_RESULT_NONE;
+
+	eeh_edev_info(edev, "Invoking %s->resume()", driver->name);
+	driver->err_handler->resume(pdev);
+
+	pci_uevent_ers(edev->pdev, PCI_ERS_RESULT_RECOVERED);
+#ifdef CONFIG_PCI_IOV
+	if (eeh_ops->notify_resume)
+		eeh_ops->notify_resume(edev);
+#endif
+	return PCI_ERS_RESULT_NONE;
+}
+
+/**
+ * eeh_report_failure - Tell device driver that device is dead.
+ * @edev: eeh device
+ * @driver: device's PCI driver
+ *
+ * This informs the device driver that the device is permanently
+ * dead, and that no further recovery attempts will be made on it.
+ */
+static enum pci_ers_result eeh_report_failure(struct eeh_dev *edev,
+					      struct pci_dev *pdev,
+					      struct pci_driver *driver)
+{
+	enum pci_ers_result rc;
+
+	if (!driver->err_handler->error_detected)
+		return PCI_ERS_RESULT_NONE;
+
+	eeh_edev_info(edev, "Invoking %s->error_detected(permanent failure)",
+		      driver->name);
+	rc = driver->err_handler->error_detected(pdev,
+						 pci_channel_io_perm_failure);
+
+	pci_uevent_ers(pdev, PCI_ERS_RESULT_DISCONNECT);
+	return rc;
+}
+
+static void *eeh_add_virt_device(struct eeh_dev *edev)
+{
+	struct pci_driver *driver;
+	struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
+
+	if (!(edev->physfn)) {
+		eeh_edev_warn(edev, "Not for VF\n");
+		return NULL;
+	}
+
+	driver = eeh_pcid_get(dev);
+	if (driver) {
+		if (driver->err_handler) {
+			eeh_pcid_put(dev);
+			return NULL;
+		}
+		eeh_pcid_put(dev);
+	}
+
+#ifdef CONFIG_PCI_IOV
+	pci_iov_add_virtfn(edev->physfn, edev->vf_index);
+#endif
+	return NULL;
+}
+
+static void eeh_rmv_device(struct eeh_dev *edev, void *userdata)
+{
+	struct pci_driver *driver;
+	struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
+	struct eeh_rmv_data *rmv_data = (struct eeh_rmv_data *)userdata;
+
+	/*
+	 * Actually, we should remove the PCI bridges as well.
+	 * However, that's lots of complexity to do that,
+	 * particularly some of devices under the bridge might
+	 * support EEH. So we just care about PCI devices for
+	 * simplicity here.
+	 */
+	if (!eeh_edev_actionable(edev) ||
+	    (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE))
+		return;
+
+	if (rmv_data) {
+		driver = eeh_pcid_get(dev);
+		if (driver) {
+			if (driver->err_handler &&
+			    driver->err_handler->error_detected &&
+			    driver->err_handler->slot_reset) {
+				eeh_pcid_put(dev);
+				return;
+			}
+			eeh_pcid_put(dev);
+		}
+	}
+
+	/* Remove it from PCI subsystem */
+	pr_info("EEH: Removing %s without EEH sensitive driver\n",
+		pci_name(dev));
+	edev->mode |= EEH_DEV_DISCONNECTED;
+	if (rmv_data)
+		rmv_data->removed_dev_count++;
+
+	if (edev->physfn) {
+#ifdef CONFIG_PCI_IOV
+		pci_iov_remove_virtfn(edev->physfn, edev->vf_index);
+		edev->pdev = NULL;
+#endif
+		if (rmv_data)
+			list_add(&edev->rmv_entry, &rmv_data->removed_vf_list);
+	} else {
+		pci_lock_rescan_remove();
+		pci_stop_and_remove_bus_device(dev);
+		pci_unlock_rescan_remove();
+	}
+}
+
+static void *eeh_pe_detach_dev(struct eeh_pe *pe, void *userdata)
+{
+	struct eeh_dev *edev, *tmp;
+
+	eeh_pe_for_each_dev(pe, edev, tmp) {
+		if (!(edev->mode & EEH_DEV_DISCONNECTED))
+			continue;
+
+		edev->mode &= ~(EEH_DEV_DISCONNECTED | EEH_DEV_IRQ_DISABLED);
+		eeh_pe_tree_remove(edev);
+	}
+
+	return NULL;
+}
+
+/*
+ * Explicitly clear PE's frozen state for PowerNV where
+ * we have frozen PE until BAR restore is completed. It's
+ * harmless to clear it for pSeries. To be consistent with
+ * PE reset (for 3 times), we try to clear the frozen state
+ * for 3 times as well.
+ */
+static int eeh_clear_pe_frozen_state(struct eeh_pe *root, bool include_passed)
+{
+	struct eeh_pe *pe;
+	int i;
+
+	eeh_for_each_pe(root, pe) {
+		if (include_passed || !eeh_pe_passed(pe)) {
+			for (i = 0; i < 3; i++)
+				if (!eeh_unfreeze_pe(pe))
+					break;
+			if (i >= 3)
+				return -EIO;
+		}
+	}
+	eeh_pe_state_clear(root, EEH_PE_ISOLATED, include_passed);
+	return 0;
+}
+
+int eeh_pe_reset_and_recover(struct eeh_pe *pe)
+{
+	int ret;
+
+	/* Bail if the PE is being recovered */
+	if (pe->state & EEH_PE_RECOVERING)
+		return 0;
+
+	/* Put the PE into recovery mode */
+	eeh_pe_state_mark(pe, EEH_PE_RECOVERING);
+
+	/* Save states */
+	eeh_pe_dev_traverse(pe, eeh_dev_save_state, NULL);
+
+	/* Issue reset */
+	ret = eeh_pe_reset_full(pe, true);
+	if (ret) {
+		eeh_pe_state_clear(pe, EEH_PE_RECOVERING, true);
+		return ret;
+	}
+
+	/* Unfreeze the PE */
+	ret = eeh_clear_pe_frozen_state(pe, true);
+	if (ret) {
+		eeh_pe_state_clear(pe, EEH_PE_RECOVERING, true);
+		return ret;
+	}
+
+	/* Restore device state */
+	eeh_pe_dev_traverse(pe, eeh_dev_restore_state, NULL);
+
+	/* Clear recovery mode */
+	eeh_pe_state_clear(pe, EEH_PE_RECOVERING, true);
+
+	return 0;
+}
+
+/**
+ * eeh_reset_device - Perform actual reset of a pci slot
+ * @driver_eeh_aware: Does the device's driver provide EEH support?
+ * @pe: EEH PE
+ * @bus: PCI bus corresponding to the isolcated slot
+ * @rmv_data: Optional, list to record removed devices
+ *
+ * This routine must be called to do reset on the indicated PE.
+ * During the reset, udev might be invoked because those affected
+ * PCI devices will be removed and then added.
+ */
+static int eeh_reset_device(struct eeh_pe *pe, struct pci_bus *bus,
+			    struct eeh_rmv_data *rmv_data,
+			    bool driver_eeh_aware)
+{
+	time64_t tstamp;
+	int cnt, rc;
+	struct eeh_dev *edev;
+	struct eeh_pe *tmp_pe;
+	bool any_passed = false;
+
+	eeh_for_each_pe(pe, tmp_pe)
+		any_passed |= eeh_pe_passed(tmp_pe);
+
+	/* pcibios will clear the counter; save the value */
+	cnt = pe->freeze_count;
+	tstamp = pe->tstamp;
+
+	/*
+	 * We don't remove the corresponding PE instances because
+	 * we need the information afterwords. The attached EEH
+	 * devices are expected to be attached soon when calling
+	 * into pci_hp_add_devices().
+	 */
+	eeh_pe_state_mark(pe, EEH_PE_KEEP);
+	if (any_passed || driver_eeh_aware || (pe->type & EEH_PE_VF)) {
+		eeh_pe_dev_traverse(pe, eeh_rmv_device, rmv_data);
+	} else {
+		pci_lock_rescan_remove();
+		pci_hp_remove_devices(bus);
+		pci_unlock_rescan_remove();
+	}
+
+	/*
+	 * Reset the pci controller. (Asserts RST#; resets config space).
+	 * Reconfigure bridges and devices. Don't try to bring the system
+	 * up if the reset failed for some reason.
+	 *
+	 * During the reset, it's very dangerous to have uncontrolled PCI
+	 * config accesses. So we prefer to block them. However, controlled
+	 * PCI config accesses initiated from EEH itself are allowed.
+	 */
+	rc = eeh_pe_reset_full(pe, false);
+	if (rc)
+		return rc;
+
+	pci_lock_rescan_remove();
+
+	/* Restore PE */
+	eeh_ops->configure_bridge(pe);
+	eeh_pe_restore_bars(pe);
+
+	/* Clear frozen state */
+	rc = eeh_clear_pe_frozen_state(pe, false);
+	if (rc) {
+		pci_unlock_rescan_remove();
+		return rc;
+	}
+
+	/* Give the system 5 seconds to finish running the user-space
+	 * hotplug shutdown scripts, e.g. ifdown for ethernet.  Yes,
+	 * this is a hack, but if we don't do this, and try to bring
+	 * the device up before the scripts have taken it down,
+	 * potentially weird things happen.
+	 */
+	if (!driver_eeh_aware || rmv_data->removed_dev_count) {
+		pr_info("EEH: Sleep 5s ahead of %s hotplug\n",
+			(driver_eeh_aware ? "partial" : "complete"));
+		ssleep(5);
+
+		/*
+		 * The EEH device is still connected with its parent
+		 * PE. We should disconnect it so the binding can be
+		 * rebuilt when adding PCI devices.
+		 */
+		edev = list_first_entry(&pe->edevs, struct eeh_dev, entry);
+		eeh_pe_traverse(pe, eeh_pe_detach_dev, NULL);
+		if (pe->type & EEH_PE_VF) {
+			eeh_add_virt_device(edev);
+		} else {
+			if (!driver_eeh_aware)
+				eeh_pe_state_clear(pe, EEH_PE_PRI_BUS, true);
+			pci_hp_add_devices(bus);
+		}
+	}
+	eeh_pe_state_clear(pe, EEH_PE_KEEP, true);
+
+	pe->tstamp = tstamp;
+	pe->freeze_count = cnt;
+
+	pci_unlock_rescan_remove();
+	return 0;
+}
+
+/* The longest amount of time to wait for a pci device
+ * to come back on line, in seconds.
+ */
+#define MAX_WAIT_FOR_RECOVERY 300
+
+
+/* Walks the PE tree after processing an event to remove any stale PEs.
+ *
+ * NB: This needs to be recursive to ensure the leaf PEs get removed
+ * before their parents do. Although this is possible to do recursively
+ * we don't since this is easier to read and we need to garantee
+ * the leaf nodes will be handled first.
+ */
+static void eeh_pe_cleanup(struct eeh_pe *pe)
+{
+	struct eeh_pe *child_pe, *tmp;
+
+	list_for_each_entry_safe(child_pe, tmp, &pe->child_list, child)
+		eeh_pe_cleanup(child_pe);
+
+	if (pe->state & EEH_PE_KEEP)
+		return;
+
+	if (!(pe->state & EEH_PE_INVALID))
+		return;
+
+	if (list_empty(&pe->edevs) && list_empty(&pe->child_list)) {
+		list_del(&pe->child);
+		kfree(pe);
+	}
+}
+
+/**
+ * eeh_check_slot_presence - Check if a device is still present in a slot
+ * @pdev: pci_dev to check
+ *
+ * This function may return a false positive if we can't determine the slot's
+ * presence state. This might happen for PCIe slots if the PE containing
+ * the upstream bridge is also frozen, or the bridge is part of the same PE
+ * as the device.
+ *
+ * This shouldn't happen often, but you might see it if you hotplug a PCIe
+ * switch.
+ */
+static bool eeh_slot_presence_check(struct pci_dev *pdev)
+{
+	const struct hotplug_slot_ops *ops;
+	struct pci_slot *slot;
+	u8 state;
+	int rc;
+
+	if (!pdev)
+		return false;
+
+	if (pdev->error_state == pci_channel_io_perm_failure)
+		return false;
+
+	slot = pdev->slot;
+	if (!slot || !slot->hotplug)
+		return true;
+
+	ops = slot->hotplug->ops;
+	if (!ops || !ops->get_adapter_status)
+		return true;
+
+	/* set the attention indicator while we've got the slot ops */
+	if (ops->set_attention_status)
+		ops->set_attention_status(slot->hotplug, 1);
+
+	rc = ops->get_adapter_status(slot->hotplug, &state);
+	if (rc)
+		return true;
+
+	return !!state;
+}
+
+static void eeh_clear_slot_attention(struct pci_dev *pdev)
+{
+	const struct hotplug_slot_ops *ops;
+	struct pci_slot *slot;
+
+	if (!pdev)
+		return;
+
+	if (pdev->error_state == pci_channel_io_perm_failure)
+		return;
+
+	slot = pdev->slot;
+	if (!slot || !slot->hotplug)
+		return;
+
+	ops = slot->hotplug->ops;
+	if (!ops || !ops->set_attention_status)
+		return;
+
+	ops->set_attention_status(slot->hotplug, 0);
+}
+
+/**
+ * eeh_handle_normal_event - Handle EEH events on a specific PE
+ * @pe: EEH PE - which should not be used after we return, as it may
+ * have been invalidated.
+ *
+ * Attempts to recover the given PE.  If recovery fails or the PE has failed
+ * too many times, remove the PE.
+ *
+ * While PHB detects address or data parity errors on particular PCI
+ * slot, the associated PE will be frozen. Besides, DMA's occurring
+ * to wild addresses (which usually happen due to bugs in device
+ * drivers or in PCI adapter firmware) can cause EEH error. #SERR,
+ * #PERR or other misc PCI-related errors also can trigger EEH errors.
+ *
+ * Recovery process consists of unplugging the device driver (which
+ * generated hotplug events to userspace), then issuing a PCI #RST to
+ * the device, then reconfiguring the PCI config space for all bridges
+ * & devices under this slot, and then finally restarting the device
+ * drivers (which cause a second set of hotplug events to go out to
+ * userspace).
+ */
+void eeh_handle_normal_event(struct eeh_pe *pe)
+{
+	struct pci_bus *bus;
+	struct eeh_dev *edev, *tmp;
+	struct eeh_pe *tmp_pe;
+	int rc = 0;
+	enum pci_ers_result result = PCI_ERS_RESULT_NONE;
+	struct eeh_rmv_data rmv_data =
+		{LIST_HEAD_INIT(rmv_data.removed_vf_list), 0};
+	int devices = 0;
+
+	bus = eeh_pe_bus_get(pe);
+	if (!bus) {
+		pr_err("%s: Cannot find PCI bus for PHB#%x-PE#%x\n",
+			__func__, pe->phb->global_number, pe->addr);
+		return;
+	}
+
+	/*
+	 * When devices are hot-removed we might get an EEH due to
+	 * a driver attempting to touch the MMIO space of a removed
+	 * device. In this case we don't have a device to recover
+	 * so suppress the event if we can't find any present devices.
+	 *
+	 * The hotplug driver should take care of tearing down the
+	 * device itself.
+	 */
+	eeh_for_each_pe(pe, tmp_pe)
+		eeh_pe_for_each_dev(tmp_pe, edev, tmp)
+			if (eeh_slot_presence_check(edev->pdev))
+				devices++;
+
+	if (!devices) {
+		pr_debug("EEH: Frozen PHB#%x-PE#%x is empty!\n",
+			pe->phb->global_number, pe->addr);
+		goto out; /* nothing to recover */
+	}
+
+	/* Log the event */
+	if (pe->type & EEH_PE_PHB) {
+		pr_err("EEH: Recovering PHB#%x, location: %s\n",
+			pe->phb->global_number, eeh_pe_loc_get(pe));
+	} else {
+		struct eeh_pe *phb_pe = eeh_phb_pe_get(pe->phb);
+
+		pr_err("EEH: Recovering PHB#%x-PE#%x\n",
+		       pe->phb->global_number, pe->addr);
+		pr_err("EEH: PE location: %s, PHB location: %s\n",
+		       eeh_pe_loc_get(pe), eeh_pe_loc_get(phb_pe));
+	}
+
+#ifdef CONFIG_STACKTRACE
+	/*
+	 * Print the saved stack trace now that we've verified there's
+	 * something to recover.
+	 */
+	if (pe->trace_entries) {
+		void **ptrs = (void **) pe->stack_trace;
+		int i;
+
+		pr_err("EEH: Frozen PHB#%x-PE#%x detected\n",
+		       pe->phb->global_number, pe->addr);
+
+		/* FIXME: Use the same format as dump_stack() */
+		pr_err("EEH: Call Trace:\n");
+		for (i = 0; i < pe->trace_entries; i++)
+			pr_err("EEH: [%pK] %pS\n", ptrs[i], ptrs[i]);
+
+		pe->trace_entries = 0;
+	}
+#endif /* CONFIG_STACKTRACE */
+
+	eeh_for_each_pe(pe, tmp_pe)
+		eeh_pe_for_each_dev(tmp_pe, edev, tmp)
+			edev->mode &= ~EEH_DEV_NO_HANDLER;
+
+	eeh_pe_update_time_stamp(pe);
+	pe->freeze_count++;
+	if (pe->freeze_count > eeh_max_freezes) {
+		pr_err("EEH: PHB#%x-PE#%x has failed %d times in the last hour and has been permanently disabled.\n",
+		       pe->phb->global_number, pe->addr,
+		       pe->freeze_count);
+
+		goto recover_failed;
+	}
+
+	/* Walk the various device drivers attached to this slot through
+	 * a reset sequence, giving each an opportunity to do what it needs
+	 * to accomplish the reset.  Each child gets a report of the
+	 * status ... if any child can't handle the reset, then the entire
+	 * slot is dlpar removed and added.
+	 *
+	 * When the PHB is fenced, we have to issue a reset to recover from
+	 * the error. Override the result if necessary to have partially
+	 * hotplug for this case.
+	 */
+	pr_warn("EEH: This PCI device has failed %d times in the last hour and will be permanently disabled after %d failures.\n",
+		pe->freeze_count, eeh_max_freezes);
+	pr_info("EEH: Notify device drivers to shutdown\n");
+	eeh_set_channel_state(pe, pci_channel_io_frozen);
+	eeh_set_irq_state(pe, false);
+	eeh_pe_report("error_detected(IO frozen)", pe,
+		      eeh_report_error, &result);
+	if (result == PCI_ERS_RESULT_DISCONNECT)
+		goto recover_failed;
+
+	/*
+	 * Error logged on a PHB are always fences which need a full
+	 * PHB reset to clear so force that to happen.
+	 */
+	if ((pe->type & EEH_PE_PHB) && result != PCI_ERS_RESULT_NONE)
+		result = PCI_ERS_RESULT_NEED_RESET;
+
+	/* Get the current PCI slot state. This can take a long time,
+	 * sometimes over 300 seconds for certain systems.
+	 */
+	rc = eeh_wait_state(pe, MAX_WAIT_FOR_RECOVERY * 1000);
+	if (rc < 0 || rc == EEH_STATE_NOT_SUPPORT) {
+		pr_warn("EEH: Permanent failure\n");
+		goto recover_failed;
+	}
+
+	/* Since rtas may enable MMIO when posting the error log,
+	 * don't post the error log until after all dev drivers
+	 * have been informed.
+	 */
+	pr_info("EEH: Collect temporary log\n");
+	eeh_slot_error_detail(pe, EEH_LOG_TEMP);
+
+	/* If all device drivers were EEH-unaware, then shut
+	 * down all of the device drivers, and hope they
+	 * go down willingly, without panicing the system.
+	 */
+	if (result == PCI_ERS_RESULT_NONE) {
+		pr_info("EEH: Reset with hotplug activity\n");
+		rc = eeh_reset_device(pe, bus, NULL, false);
+		if (rc) {
+			pr_warn("%s: Unable to reset, err=%d\n", __func__, rc);
+			goto recover_failed;
+		}
+	}
+
+	/* If all devices reported they can proceed, then re-enable MMIO */
+	if (result == PCI_ERS_RESULT_CAN_RECOVER) {
+		pr_info("EEH: Enable I/O for affected devices\n");
+		rc = eeh_pci_enable(pe, EEH_OPT_THAW_MMIO);
+		if (rc < 0)
+			goto recover_failed;
+
+		if (rc) {
+			result = PCI_ERS_RESULT_NEED_RESET;
+		} else {
+			pr_info("EEH: Notify device drivers to resume I/O\n");
+			eeh_pe_report("mmio_enabled", pe,
+				      eeh_report_mmio_enabled, &result);
+		}
+	}
+	if (result == PCI_ERS_RESULT_CAN_RECOVER) {
+		pr_info("EEH: Enabled DMA for affected devices\n");
+		rc = eeh_pci_enable(pe, EEH_OPT_THAW_DMA);
+		if (rc < 0)
+			goto recover_failed;
+
+		if (rc) {
+			result = PCI_ERS_RESULT_NEED_RESET;
+		} else {
+			/*
+			 * We didn't do PE reset for the case. The PE
+			 * is still in frozen state. Clear it before
+			 * resuming the PE.
+			 */
+			eeh_pe_state_clear(pe, EEH_PE_ISOLATED, true);
+			result = PCI_ERS_RESULT_RECOVERED;
+		}
+	}
+
+	/* If any device called out for a reset, then reset the slot */
+	if (result == PCI_ERS_RESULT_NEED_RESET) {
+		pr_info("EEH: Reset without hotplug activity\n");
+		rc = eeh_reset_device(pe, bus, &rmv_data, true);
+		if (rc) {
+			pr_warn("%s: Cannot reset, err=%d\n", __func__, rc);
+			goto recover_failed;
+		}
+
+		result = PCI_ERS_RESULT_NONE;
+		eeh_set_channel_state(pe, pci_channel_io_normal);
+		eeh_set_irq_state(pe, true);
+		eeh_pe_report("slot_reset", pe, eeh_report_reset,
+			      &result);
+	}
+
+	if ((result == PCI_ERS_RESULT_RECOVERED) ||
+	    (result == PCI_ERS_RESULT_NONE)) {
+		/*
+		 * For those hot removed VFs, we should add back them after PF
+		 * get recovered properly.
+		 */
+		list_for_each_entry_safe(edev, tmp, &rmv_data.removed_vf_list,
+					 rmv_entry) {
+			eeh_add_virt_device(edev);
+			list_del(&edev->rmv_entry);
+		}
+
+		/* Tell all device drivers that they can resume operations */
+		pr_info("EEH: Notify device driver to resume\n");
+		eeh_set_channel_state(pe, pci_channel_io_normal);
+		eeh_set_irq_state(pe, true);
+		eeh_pe_report("resume", pe, eeh_report_resume, NULL);
+		eeh_for_each_pe(pe, tmp_pe) {
+			eeh_pe_for_each_dev(tmp_pe, edev, tmp) {
+				edev->mode &= ~EEH_DEV_NO_HANDLER;
+				edev->in_error = false;
+			}
+		}
+
+		pr_info("EEH: Recovery successful.\n");
+		goto out;
+	}
+
+recover_failed:
+	/*
+	 * About 90% of all real-life EEH failures in the field
+	 * are due to poorly seated PCI cards. Only 10% or so are
+	 * due to actual, failed cards.
+	 */
+	pr_err("EEH: Unable to recover from failure from PHB#%x-PE#%x.\n"
+		"Please try reseating or replacing it\n",
+		pe->phb->global_number, pe->addr);
+
+	eeh_slot_error_detail(pe, EEH_LOG_PERM);
+
+	/* Notify all devices that they're about to go down. */
+	eeh_set_channel_state(pe, pci_channel_io_perm_failure);
+	eeh_set_irq_state(pe, false);
+	eeh_pe_report("error_detected(permanent failure)", pe,
+		      eeh_report_failure, NULL);
+
+	/* Mark the PE to be removed permanently */
+	eeh_pe_state_mark(pe, EEH_PE_REMOVED);
+
+	/*
+	 * Shut down the device drivers for good. We mark
+	 * all removed devices correctly to avoid access
+	 * the their PCI config any more.
+	 */
+	if (pe->type & EEH_PE_VF) {
+		eeh_pe_dev_traverse(pe, eeh_rmv_device, NULL);
+		eeh_pe_dev_mode_mark(pe, EEH_DEV_REMOVED);
+	} else {
+		eeh_pe_state_clear(pe, EEH_PE_PRI_BUS, true);
+		eeh_pe_dev_mode_mark(pe, EEH_DEV_REMOVED);
+
+		pci_lock_rescan_remove();
+		pci_hp_remove_devices(bus);
+		pci_unlock_rescan_remove();
+		/* The passed PE should no longer be used */
+		return;
+	}
+
+out:
+	/*
+	 * Clean up any PEs without devices. While marked as EEH_PE_RECOVERYING
+	 * we don't want to modify the PE tree structure so we do it here.
+	 */
+	eeh_pe_cleanup(pe);
+
+	/* clear the slot attention LED for all recovered devices */
+	eeh_for_each_pe(pe, tmp_pe)
+		eeh_pe_for_each_dev(tmp_pe, edev, tmp)
+			eeh_clear_slot_attention(edev->pdev);
+
+	eeh_pe_state_clear(pe, EEH_PE_RECOVERING, true);
+}
+
+/**
+ * eeh_handle_special_event - Handle EEH events without a specific failing PE
+ *
+ * Called when an EEH event is detected but can't be narrowed down to a
+ * specific PE.  Iterates through possible failures and handles them as
+ * necessary.
+ */
+void eeh_handle_special_event(void)
+{
+	struct eeh_pe *pe, *phb_pe, *tmp_pe;
+	struct eeh_dev *edev, *tmp_edev;
+	struct pci_bus *bus;
+	struct pci_controller *hose;
+	unsigned long flags;
+	int rc;
+
+
+	do {
+		rc = eeh_ops->next_error(&pe);
+
+		switch (rc) {
+		case EEH_NEXT_ERR_DEAD_IOC:
+			/* Mark all PHBs in dead state */
+			eeh_serialize_lock(&flags);
+
+			/* Purge all events */
+			eeh_remove_event(NULL, true);
+
+			list_for_each_entry(hose, &hose_list, list_node) {
+				phb_pe = eeh_phb_pe_get(hose);
+				if (!phb_pe) continue;
+
+				eeh_pe_mark_isolated(phb_pe);
+			}
+
+			eeh_serialize_unlock(flags);
+
+			break;
+		case EEH_NEXT_ERR_FROZEN_PE:
+		case EEH_NEXT_ERR_FENCED_PHB:
+		case EEH_NEXT_ERR_DEAD_PHB:
+			/* Mark the PE in fenced state */
+			eeh_serialize_lock(&flags);
+
+			/* Purge all events of the PHB */
+			eeh_remove_event(pe, true);
+
+			if (rc != EEH_NEXT_ERR_DEAD_PHB)
+				eeh_pe_state_mark(pe, EEH_PE_RECOVERING);
+			eeh_pe_mark_isolated(pe);
+
+			eeh_serialize_unlock(flags);
+
+			break;
+		case EEH_NEXT_ERR_NONE:
+			return;
+		default:
+			pr_warn("%s: Invalid value %d from next_error()\n",
+				__func__, rc);
+			return;
+		}
+
+		/*
+		 * For fenced PHB and frozen PE, it's handled as normal
+		 * event. We have to remove the affected PHBs for dead
+		 * PHB and IOC
+		 */
+		if (rc == EEH_NEXT_ERR_FROZEN_PE ||
+		    rc == EEH_NEXT_ERR_FENCED_PHB) {
+			eeh_pe_state_mark(pe, EEH_PE_RECOVERING);
+			eeh_handle_normal_event(pe);
+		} else {
+			eeh_for_each_pe(pe, tmp_pe)
+				eeh_pe_for_each_dev(tmp_pe, edev, tmp_edev)
+					edev->mode &= ~EEH_DEV_NO_HANDLER;
+
+			/* Notify all devices to be down */
+			eeh_pe_state_clear(pe, EEH_PE_PRI_BUS, true);
+			eeh_set_channel_state(pe, pci_channel_io_perm_failure);
+			eeh_pe_report(
+				"error_detected(permanent failure)", pe,
+				eeh_report_failure, NULL);
+
+			pci_lock_rescan_remove();
+			list_for_each_entry(hose, &hose_list, list_node) {
+				phb_pe = eeh_phb_pe_get(hose);
+				if (!phb_pe ||
+				    !(phb_pe->state & EEH_PE_ISOLATED) ||
+				    (phb_pe->state & EEH_PE_RECOVERING))
+					continue;
+
+				bus = eeh_pe_bus_get(phb_pe);
+				if (!bus) {
+					pr_err("%s: Cannot find PCI bus for "
+					       "PHB#%x-PE#%x\n",
+					       __func__,
+					       pe->phb->global_number,
+					       pe->addr);
+					break;
+				}
+				pci_hp_remove_devices(bus);
+			}
+			pci_unlock_rescan_remove();
+		}
+
+		/*
+		 * If we have detected dead IOC, we needn't proceed
+		 * any more since all PHBs would have been removed
+		 */
+		if (rc == EEH_NEXT_ERR_DEAD_IOC)
+			break;
+	} while (rc != EEH_NEXT_ERR_NONE);
+}