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Subject[PATCH 24/42]: ppc64: PCI Error Recovery: PPC64 core recovery routines
Various PCI bus errors can be signaled by newer PCI controllers.  The
core error recovery routines are architecture dependent. This patch adds
a recovery infrastructure for the PPC64 pSeries systems.

Signed-off-by: Linas Vepstas <linas@austin.ibm.com>

Index: linux-2.6.14-git3/arch/powerpc/platforms/pseries/eeh.c
===================================================================
--- linux-2.6.14-git3.orig/arch/powerpc/platforms/pseries/eeh.c 2005-11-02 14:36:41.255317484 -0600
+++ linux-2.6.14-git3/arch/powerpc/platforms/pseries/eeh.c 2005-11-02 14:41:18.427452474 -0600
@@ -485,6 +485,11 @@
if (PCI_DN(dn)) {
PCI_DN(dn)->eeh_mode |= mode_flag;

+ /* Mark the pci device driver too */
+ struct pci_dev *dev = PCI_DN(dn)->pcidev;
+ if (dev && dev->driver)
+ dev->error_state = pci_channel_io_frozen;
+
if (dn->child)
__eeh_mark_slot (dn->child, mode_flag);
}
@@ -544,6 +549,7 @@
int rets[3];
unsigned long flags;
struct pci_dn *pdn;
+ enum pci_channel_state state;
int rc = 0;

__get_cpu_var(total_mmio_ffs)++;
@@ -648,8 +654,13 @@
eeh_mark_slot (dn, EEH_MODE_ISOLATED);
spin_unlock_irqrestore(&confirm_error_lock, flags);

- eeh_send_failure_event (dn, dev, rets[0], rets[2]);
-
+ state = pci_channel_io_normal;
+ if ((rets[0] == 2) || (rets[0] == 4))
+ state = pci_channel_io_frozen;
+ if (rets[0] == 5)
+ state = pci_channel_io_perm_failure;
+ eeh_send_failure_event (dn, dev, state, rets[2]);
+
/* Most EEH events are due to device driver bugs. Having
* a stack trace will help the device-driver authors figure
* out what happened. So print that out. */
@@ -953,8 +964,10 @@
* But there are a few cases like display devices that make sense.
*/
enable = 1; /* i.e. we will do checking */
+#if 0
if ((*class_code >> 16) == PCI_BASE_CLASS_DISPLAY)
enable = 0;
+#endif

if (!enable)
pdn->eeh_mode |= EEH_MODE_NOCHECK;
Index: linux-2.6.14-git3/arch/powerpc/platforms/pseries/eeh_driver.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.14-git3/arch/powerpc/platforms/pseries/eeh_driver.c 2005-11-02 14:41:18.435451353 -0600
@@ -0,0 +1,366 @@
+/*
+ * PCI Error Recovery Driver for RPA-compliant PPC64 platform.
+ * Copyright (C) 2004, 2005 Linas Vepstas <linas@linas.org>
+ *
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or (at
+ * your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ * NON INFRINGEMENT. See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * Send feedback to <linas@us.ibm.com>
+ *
+ */
+#include <linux/delay.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/notifier.h>
+#include <linux/pci.h>
+#include <asm/eeh.h>
+#include <asm/eeh_event.h>
+#include <asm/ppc-pci.h>
+#include <asm/pci-bridge.h>
+#include <asm/prom.h>
+#include <asm/rtas.h>
+
+
+static inline const char * pcid_name (struct pci_dev *pdev)
+{
+ if (pdev->dev.driver)
+ return pdev->dev.driver->name;
+ return "";
+}
+
+/**
+ * Return the "partitionable endpoint" (pe) under which this device lies
+ */
+static struct device_node * find_device_pe(struct device_node *dn)
+{
+ while ((dn->parent) && PCI_DN(dn->parent) &&
+ (PCI_DN(dn->parent)->eeh_mode & EEH_MODE_SUPPORTED)) {
+ dn = dn->parent;
+ }
+ return dn;
+}
+
+
+#ifdef DEBUG
+static void print_device_node_tree (struct pci_dn *pdn, int dent)
+{
+ int i;
+ if (!pdn) return;
+ for (i=0;i<dent; i++)
+ printk(" ");
+ printk("dn=%s mode=%x \tcfg_addr=%x pe_addr=%x \tfull=%s\n",
+ pdn->node->name, pdn->eeh_mode, pdn->eeh_config_addr,
+ pdn->eeh_pe_config_addr, pdn->node->full_name);
+ dent += 3;
+ struct device_node *pc = pdn->node->child;
+ while (pc) {
+ print_device_node_tree(PCI_DN(pc), dent);
+ pc = pc->sibling;
+ }
+}
+#endif
+
+/**
+ * irq_in_use - return true if this irq is being used
+ */
+static int irq_in_use(unsigned int irq)
+{
+ int rc = 0;
+ unsigned long flags;
+ struct irq_desc *desc = irq_desc + irq;
+
+ spin_lock_irqsave(&desc->lock, flags);
+ if (desc->action)
+ rc = 1;
+ spin_unlock_irqrestore(&desc->lock, flags);
+ return rc;
+}
+
+/* ------------------------------------------------------- */
+/** eeh_report_error - report an EEH error to each device,
+ * collect up and merge the device responses.
+ */
+
+static void eeh_report_error(struct pci_dev *dev, void *userdata)
+{
+ enum pcierr_result rc, *res = userdata;
+ struct pci_driver *driver = dev->driver;
+
+ dev->error_state = pci_channel_io_frozen;
+
+ if (!driver)
+ return;
+
+ if (irq_in_use (dev->irq)) {
+ struct device_node *dn = pci_device_to_OF_node(dev);
+ PCI_DN(dn)->eeh_mode |= EEH_MODE_IRQ_DISABLED;
+ disable_irq_nosync(dev->irq);
+ }
+ if (!driver->err_handler)
+ return;
+ if (!driver->err_handler->error_detected)
+ return;
+
+ rc = driver->err_handler->error_detected (dev, pci_channel_io_frozen);
+ if (*res == PCIERR_RESULT_NONE) *res = rc;
+ if (*res == PCIERR_RESULT_NEED_RESET) return;
+ if (*res == PCIERR_RESULT_DISCONNECT &&
+ rc == PCIERR_RESULT_NEED_RESET) *res = rc;
+}
+
+/** eeh_report_reset -- tell this device that the pci slot
+ * has been reset.
+ */
+
+static void eeh_report_reset(struct pci_dev *dev, void *userdata)
+{
+ struct pci_driver *driver = dev->driver;
+ struct device_node *dn = pci_device_to_OF_node(dev);
+
+ if (!driver)
+ return;
+
+ if ((PCI_DN(dn)->eeh_mode) & EEH_MODE_IRQ_DISABLED) {
+ PCI_DN(dn)->eeh_mode &= ~EEH_MODE_IRQ_DISABLED;
+ enable_irq(dev->irq);
+ }
+ if (!driver->err_handler)
+ return;
+ if (!driver->err_handler->slot_reset)
+ return;
+
+ driver->err_handler->slot_reset(dev);
+}
+
+static void eeh_report_resume(struct pci_dev *dev, void *userdata)
+{
+ struct pci_driver *driver = dev->driver;
+
+ dev->error_state = pci_channel_io_normal;
+
+ if (!driver)
+ return;
+ if (!driver->err_handler)
+ return;
+ if (!driver->err_handler->resume)
+ return;
+
+ driver->err_handler->resume(dev);
+}
+
+static void eeh_report_failure(struct pci_dev *dev, void *userdata)
+{
+ struct pci_driver *driver = dev->driver;
+
+ dev->error_state = pci_channel_io_perm_failure;
+
+ if (!driver)
+ return;
+
+ if (irq_in_use (dev->irq)) {
+ struct device_node *dn = pci_device_to_OF_node(dev);
+ PCI_DN(dn)->eeh_mode |= EEH_MODE_IRQ_DISABLED;
+ disable_irq_nosync(dev->irq);
+ }
+ if (!driver->err_handler)
+ return;
+ if (!driver->err_handler->error_detected)
+ return;
+ driver->err_handler->error_detected(dev, pci_channel_io_perm_failure);
+}
+
+/* ------------------------------------------------------- */
+/**
+ * handle_eeh_events -- reset a PCI device after hard lockup.
+ *
+ * pSeries systems will isolate a PCI slot if the PCI-Host
+ * bridge detects address or data parity errors, DMA's
+ * occuring to wild addresses (which usually happen due to
+ * bugs in device drivers or in PCI adapter firmware).
+ * Slot isolations also occur if #SERR, #PERR or other misc
+ * PCI-related errors are detected.
+ *
+ * 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).
+ */
+
+/**
+ * eeh_reset_device() -- perform actual reset of a pci slot
+ * Args: bus: pointer to the pci bus structure corresponding
+ * to the isolated slot. A non-null value will
+ * cause all devices under the bus to be removed
+ * and then re-added.
+ * pe_dn: pointer to a "Partionable Endpoint" device node.
+ * This is the top-level structure on which pci
+ * bus resets can be performed.
+ */
+
+static void eeh_reset_device (struct pci_dn *pe_dn, struct pci_bus *bus)
+{
+ if (bus)
+ pcibios_remove_pci_devices(bus);
+
+ /* Reset the pci controller. (Asserts RST#; resets config space).
+ * Reconfigure bridges and devices */
+ rtas_set_slot_reset(pe_dn);
+
+ /* Walk over all functions on this device */
+ rtas_configure_bridge(pe_dn);
+ eeh_restore_bars(pe_dn);
+
+ /* 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 (bus) {
+ ssleep (5);
+ pcibios_add_pci_devices(bus);
+ }
+}
+
+/* The longest amount of time to wait for a pci device
+ * to come back on line, in seconds.
+ */
+#define MAX_WAIT_FOR_RECOVERY 15
+
+void handle_eeh_events (struct eeh_event *event)
+{
+ struct device_node *frozen_dn;
+ struct pci_dn *frozen_pdn;
+ struct pci_bus *frozen_bus;
+ int perm_failure = 0;
+
+ frozen_dn = find_device_pe(event->dn);
+ frozen_bus = pcibios_find_pci_bus(frozen_dn);
+
+ if (!frozen_dn) {
+ printk(KERN_ERR "EEH: Error: Cannot find partition endpoint for %s\n",
+ pci_name(event->dev));
+ return;
+ }
+
+ /* There are two different styles for coming up with the PE.
+ * In the old style, it was the highest EEH-capable device
+ * which was always an EADS pci bridge. In the new style,
+ * there might not be any EADS bridges, and even when there are,
+ * the firmware marks them as "EEH incapable". So another
+ * two-step is needed to find the pci bus.. */
+ if (!frozen_bus)
+ frozen_bus = pcibios_find_pci_bus (frozen_dn->parent);
+
+ if (!frozen_bus) {
+ printk(KERN_ERR "EEH: Cannot find PCI bus for %s\n",
+ frozen_dn->full_name);
+ return;
+ }
+
+#if 0
+ /* We may get "permanent failure" messages on empty slots.
+ * These are false alarms. Empty slots have no child dn. */
+ if ((event->state == pci_channel_io_perm_failure) && (frozen_device == NULL))
+ return;
+#endif
+
+ frozen_pdn = PCI_DN(frozen_dn);
+ frozen_pdn->eeh_freeze_count++;
+
+ if (frozen_pdn->eeh_freeze_count > EEH_MAX_ALLOWED_FREEZES)
+ perm_failure = 1;
+
+ /* If the reset state is a '5' and the time to reset is 0 (infinity)
+ * or is more then 15 seconds, then mark this as a permanent failure.
+ */
+ if ((event->state == pci_channel_io_perm_failure) &&
+ ((event->time_unavail <= 0) ||
+ (event->time_unavail > MAX_WAIT_FOR_RECOVERY*1000)))
+ {
+ perm_failure = 1;
+ }
+
+ /* Log the error with the rtas logger. */
+ if (perm_failure) {
+ /*
+ * 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.
+ */
+ printk(KERN_ERR
+ "EEH: PCI device %s - %s has failed %d times \n"
+ "and has been permanently disabled. Please try reseating\n"
+ "this device or replacing it.\n",
+ pci_name (frozen_pdn->pcidev),
+ pcid_name(frozen_pdn->pcidev),
+ frozen_pdn->eeh_freeze_count);
+
+ eeh_slot_error_detail(frozen_pdn, 2 /* Permanent Error */);
+
+ /* Notify all devices that they're about to go down. */
+ pci_walk_bus(frozen_bus, eeh_report_failure, 0);
+
+ /* Shut down the device drivers for good. */
+ pcibios_remove_pci_devices(frozen_bus);
+ return;
+ }
+
+ eeh_slot_error_detail(frozen_pdn, 1 /* Temporary Error */);
+ printk(KERN_WARNING
+ "EEH: This PCI device has failed %d times since last reboot: %s - %s\n",
+ frozen_pdn->eeh_freeze_count,
+ pci_name (frozen_pdn->pcidev),
+ pcid_name(frozen_pdn->pcidev));
+
+ /* 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.
+ */
+ enum pcierr_result result = PCIERR_RESULT_NONE;
+ pci_walk_bus(frozen_bus, eeh_report_error, &result);
+
+ /* 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 == PCIERR_RESULT_NONE) {
+ eeh_reset_device(frozen_pdn, frozen_bus);
+ }
+
+ /* If any device called out for a reset, then reset the slot */
+ if (result == PCIERR_RESULT_NEED_RESET) {
+ eeh_reset_device(frozen_pdn, NULL);
+ pci_walk_bus(frozen_bus, eeh_report_reset, 0);
+ }
+
+ /* If all devices reported they can proceed, the re-enable PIO */
+ if (result == PCIERR_RESULT_CAN_RECOVER) {
+ /* XXX Not supported; we brute-force reset the device */
+ eeh_reset_device(frozen_pdn, NULL);
+ pci_walk_bus(frozen_bus, eeh_report_reset, 0);
+ }
+
+ /* Tell all device drivers that they can resume operations */
+ pci_walk_bus(frozen_bus, eeh_report_resume, 0);
+}
+
+/* ---------- end of file ---------- */
Index: linux-2.6.14-git3/arch/powerpc/platforms/pseries/eeh_event.c
===================================================================
--- linux-2.6.14-git3.orig/arch/powerpc/platforms/pseries/eeh_event.c 2005-11-02 14:32:35.731739983 -0600
+++ linux-2.6.14-git3/arch/powerpc/platforms/pseries/eeh_event.c 2005-11-02 14:41:18.440450652 -0600
@@ -21,6 +21,7 @@
#include <linux/list.h>
#include <linux/pci.h>
#include <asm/eeh_event.h>
+#include <asm/ppc-pci.h>

/** Overview:
* EEH error states may be detected within exception handlers;
@@ -37,31 +38,6 @@
DECLARE_WORK(eeh_event_wq, eeh_thread_launcher, NULL);

/**
- * eeh_panic - call panic() for an eeh event that cannot be handled.
- * The philosophy of this routine is that it is better to panic and
- * halt the OS than it is to risk possible data corruption by
- * oblivious device drivers that don't know better.
- *
- * @dev pci device that had an eeh event
- * @reset_state current reset state of the device slot
- */
-static void eeh_panic(struct pci_dev *dev, int reset_state)
-{
- /*
- * Since the panic_on_oops sysctl is used to halt the system
- * in light of potential corruption, we can use it here.
- */
- if (panic_on_oops) {
- panic("EEH: MMIO failure (%d) on device:%s\n", reset_state,
- pci_name(dev));
- }
- else {
- printk(KERN_INFO "EEH: Ignored MMIO failure (%d) on device:%s\n",
- reset_state, pci_name(dev));
- }
-}
-
-/**
* eeh_event_handler - dispatch EEH events. The detection of a frozen
* slot can occur inside an interrupt, where it can be hard to do
* anything about it. The goal of this routine is to pull these
@@ -82,10 +58,16 @@

spin_lock_irqsave(&eeh_eventlist_lock, flags);
event = NULL;
+
+ /* Unqueue the event, get ready to process. */
if (!list_empty(&eeh_eventlist)) {
event = list_entry(eeh_eventlist.next, struct eeh_event, list);
list_del(&event->list);
}
+
+ if (event)
+ eeh_mark_slot(event->dn, EEH_MODE_RECOVERING);
+
spin_unlock_irqrestore(&eeh_eventlist_lock, flags);
if (event == NULL)
break;
@@ -93,8 +75,11 @@
printk(KERN_INFO "EEH: Detected PCI bus error on device %s\n",
pci_name(event->dev));

- eeh_panic (event->dev, event->state);
+ handle_eeh_events(event);
+
+ eeh_clear_slot(event->dn, EEH_MODE_RECOVERING);

+ pci_dev_put(event->dev);
kfree(event);
}

@@ -122,7 +107,7 @@
*/
int eeh_send_failure_event (struct device_node *dn,
struct pci_dev *dev,
- int state,
+ enum pci_channel_state state,
int time_unavail)
{
unsigned long flags;
Index: linux-2.6.14-git3/include/asm-powerpc/eeh_event.h
===================================================================
--- linux-2.6.14-git3.orig/include/asm-powerpc/eeh_event.h 2005-11-02 14:32:35.718741805 -0600
+++ linux-2.6.14-git3/include/asm-powerpc/eeh_event.h 2005-11-02 14:41:18.444450091 -0600
@@ -29,7 +29,7 @@
struct list_head list;
struct device_node *dn; /* struct device node */
struct pci_dev *dev; /* affected device */
- int state;
+ enum pci_channel_state state; /* PCI bus state for the affected device */
int time_unavail; /* milliseconds until device might be available */
};

@@ -46,7 +46,10 @@
*/
int eeh_send_failure_event (struct device_node *dn,
struct pci_dev *dev,
- int reset_state,
+ enum pci_channel_state state,
int time_unavail);

+/* Main recovery function */
+void handle_eeh_events (struct eeh_event *);
+
#endif /* ASM_PPC64_EEH_EVENT_H */
Index: linux-2.6.14-git3/arch/powerpc/platforms/pseries/Makefile
===================================================================
--- linux-2.6.14-git3.orig/arch/powerpc/platforms/pseries/Makefile 2005-11-02 14:40:05.531674439 -0600
+++ linux-2.6.14-git3/arch/powerpc/platforms/pseries/Makefile 2005-11-02 14:41:48.393250352 -0600
@@ -3,4 +3,4 @@
obj-$(CONFIG_SMP) += smp.o
obj-$(CONFIG_IBMVIO) += vio.o
obj-$(CONFIG_XICS) += xics.o
-obj-$(CONFIG_EEH) += eeh.o eeh_event.o
+obj-$(CONFIG_EEH) += eeh.o eeh_driver.o eeh_event.o
Index: linux-2.6.14-git3/include/asm-powerpc/ppc-pci.h
===================================================================
--- linux-2.6.14-git3.orig/include/asm-powerpc/ppc-pci.h 2005-11-02 14:35:39.295004776 -0600
+++ linux-2.6.14-git3/include/asm-powerpc/ppc-pci.h 2005-11-02 14:41:18.454448689 -0600
@@ -54,6 +54,15 @@
/* ---- EEH internal-use-only related routines ---- */
#ifdef CONFIG_EEH
/**
+ * eeh_slot_error_detail -- record and EEH error condition to the log
+ * @severity: 1 if temporary, 2 if permanent failure.
+ *
+ * Obtains the the EEH error details from the RTAS subsystem,
+ * and then logs these details with the RTAS error log system.
+ */
+void eeh_slot_error_detail (struct pci_dn *pdn, int severity);
+
+/**
* rtas_set_slot_reset -- unfreeze a frozen slot
*
* Clear the EEH-frozen condition on a slot. This routine
Index: linux-2.6.14-git3/include/asm-ppc64/eeh.h
===================================================================
--- linux-2.6.14-git3.orig/include/asm-ppc64/eeh.h 2005-11-02 14:36:41.263316362 -0600
+++ linux-2.6.14-git3/include/asm-ppc64/eeh.h 2005-11-02 14:41:18.461447707 -0600
@@ -31,9 +31,11 @@
#ifdef CONFIG_EEH

/* Values for eeh_mode bits in device_node */
-#define EEH_MODE_SUPPORTED (1<<0)
-#define EEH_MODE_NOCHECK (1<<1)
-#define EEH_MODE_ISOLATED (1<<2)
+#define EEH_MODE_SUPPORTED (1<<0)
+#define EEH_MODE_NOCHECK (1<<1)
+#define EEH_MODE_ISOLATED (1<<2)
+#define EEH_MODE_RECOVERING (1<<3)
+#define EEH_MODE_IRQ_DISABLED (1<<4)

/* Max number of EEH freezes allowed before we consider the device
* to be permanently disabled. */
-
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