/*
* PCI Error Recovery Driver for RPA-compliant PPC64 platform.
* Copyright IBM Corp. 2004 2005
* Copyright Linas Vepstas <linas@linas.org> 2004, 2005
*
* 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 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 <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>
/**
* eeh_pcid_name - Retrieve name of PCI device driver
* @pdev: PCI device
*
* This routine is used to retrieve the name of PCI device driver
* if that's valid.
*/
static inline const char *eeh_pcid_name(struct pci_dev *pdev)
{
if (pdev && pdev->dev.driver)
return pdev->dev.driver->name;
return "";
}
/**
* 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->driver)
return NULL;
if (!try_module_get(pdev->driver->driver.owner))
return NULL;
return pdev->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->driver)
return;
module_put(pdev->driver->driver.owner);
}
#if 0
static void print_device_node_tree(struct pci_dn *pdn, int dent)
{
int i;
struct device_node *pc;
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;
pc = pdn->node->child;
while (pc) {
print_device_node_tree(PCI_DN(pc), dent);
pc = pc->sibling;
}
}
#endif
/**
* 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 pci_dev *dev)
{
struct eeh_dev *edev = pci_dev_to_eeh_dev(dev);
/* Don't disable MSI and MSI-X interrupts. They are
* effectively disabled by the DMA Stopped state
* when an EEH error occurs.
*/
if (dev->msi_enabled || dev->msix_enabled)
return;
if (!irq_has_action(dev->irq))
return;
edev->mode |= EEH_DEV_IRQ_DISABLED;
disable_irq_nosync(dev->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 pci_dev *dev)
{
struct eeh_dev *edev = pci_dev_to_eeh_dev(dev);
if ((edev->mode) & EEH_DEV_IRQ_DISABLED) {
edev->mode &= ~EEH_DEV_IRQ_DISABLED;
enable_irq(dev->irq);
}
}
/**
* eeh_report_error - Report pci error to each device driver
* @data: eeh device
* @userdata: return value
*
* Report an EEH error to each device driver, collect up and
* merge the device driver responses. Cumulative response
* passed back in "userdata".
*/
static void *eeh_report_error(void *data, void *userdata)
{
struct eeh_dev *edev = (struct eeh_dev *)data;
struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
enum pci_ers_result rc, *res = userdata;
struct pci_driver *driver;
/* We might not have the associated PCI device,
* then we should continue for next one.
*/
if (!dev) return NULL;
dev->error_state = pci_channel_io_frozen;
driver = eeh_pcid_get(dev);
if (!driver) return NULL;
eeh_disable_irq(dev);
if (!driver->err_handler ||
!driver->err_handler->error_detected) {
eeh_pcid_put(dev);
return NULL;
}
rc = driver->err_handler->error_detected(dev, pci_channel_io_frozen);
/* A driver that needs a reset trumps all others */
if (rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
if (*res == PCI_ERS_RESULT_NONE) *res = rc;
eeh_pcid_put(dev);
return NULL;
}
/**
* eeh_report_mmio_enabled - Tell drivers that MMIO has been enabled
* @data: eeh device
* @userdata: return value
*
* Tells each device driver that IO ports, MMIO and config space I/O
* are now enabled. Collects up and merges the device driver responses.
* Cumulative response passed back in "userdata".
*/
static void *eeh_report_mmio_enabled(void *data, void *userdata)
{
struct eeh_dev *edev = (struct eeh_dev *)data;
struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
enum pci_ers_result rc, *res = userdata;
struct pci_driver *driver;
driver = eeh_pcid_get(dev);
if (!driver) return NULL;
if (!driver->err_handler ||
!driver->err_handler->mmio_enabled) {
eeh_pcid_put(dev);
return NULL;
}
rc = driver->err_handler->mmio_enabled(dev);
/* A driver that needs a reset trumps all others */
if (rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
if (*res == PCI_ERS_RESULT_NONE) *res = rc;
eeh_pcid_put(dev);
return NULL;
}
/**
* eeh_report_reset - Tell device that slot has been reset
* @data: eeh device
* @userdata: return value
*
* 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 void *eeh_report_reset(void *data, void *userdata)
{
struct eeh_dev *edev = (struct eeh_dev *)data;
struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
enum pci_ers_result rc, *res = userdata;
struct pci_driver *driver;
if (!dev) return NULL;
dev->error_state = pci_channel_io_normal;
driver = eeh_pcid_get(dev);
if (!driver) return NULL;
eeh_enable_irq(dev);
if (!driver->err_handler ||
!driver->err_handler->slot_reset) {
eeh_pcid_put(dev);
return NULL;
}
rc = driver->err_handler->slot_reset(dev);
if ((*res == PCI_ERS_RESULT_NONE) ||
(*res == PCI_ERS_RESULT_RECOVERED)) *res = rc;
if (*res == PCI_ERS_RESULT_DISCONNECT &&
rc == PCI_ERS_RESULT_NEED_RESET) *res = rc;
eeh_pcid_put(dev);
return NULL;
}
/**
* eeh_report_resume - Tell device to resume normal operations
* @data: eeh device
* @userdata: return value
*
* 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 void *eeh_report_resume(void *data, void *userdata)
{
struct eeh_dev *edev = (struct eeh_dev *)data;
struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
struct pci_driver *driver;
if (!dev) return NULL;
dev->error_state = pci_channel_io_normal;
driver = eeh_pcid_get(dev);
if (!driver) return NULL;
eeh_enable_irq(dev);
if (!driver->err_handler ||
!driver->err_handler->resume) {
eeh_pcid_put(dev);
return NULL;
}
driver->err_handler->resume(dev);
eeh_pcid_put(dev);
return NULL;
}
/**
* eeh_report_failure - Tell device driver that device is dead.
* @data: eeh device
* @userdata: return value
*
* This informs the device driver that the device is permanently
* dead, and that no further recovery attempts will be made on it.
*/
static void *eeh_report_failure(void *data, void *userdata)
{
struct eeh_dev *edev = (struct eeh_dev *)data;
struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
struct pci_driver *driver;
if (!dev) return NULL;
dev->error_state = pci_channel_io_perm_failure;
driver = eeh_pcid_get(dev);
if (!driver) return NULL;
eeh_disable_irq(dev);
if (!driver->err_handler ||
!driver->err_handler->error_detected) {
eeh_pcid_put(dev);
return NULL;
}
driver->err_handler->error_detected(dev, pci_channel_io_perm_failure);
eeh_pcid_put(dev);
return NULL;
}
/**
* eeh_reset_device - Perform actual reset of a pci slot
* @pe: EEH PE
* @bus: PCI bus corresponding to the isolcated slot
*
* 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)
{
int cnt, rc;
/* pcibios will clear the counter; save the value */
cnt = pe->freeze_count;
/*
* 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 pcibios_add_pci_devices().
*/
if (bus)
__pcibios_remove_pci_devices(bus, 0);
/* 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.
*/
rc = eeh_reset_pe(pe);
if (rc)
return rc;
/* Restore PE */
eeh_ops->configure_bridge(pe);
eeh_pe_restore_bars(pe);
/* 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);
}
pe->freeze_count = cnt;
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 150
/**
* eeh_handle_event - Reset a PCI device after hard lockup.
* @pe: EEH 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_event(struct eeh_pe *pe)
{
struct pci_bus *frozen_bus;
int rc = 0;
enum pci_ers_result result = PCI_ERS_RESULT_NONE;
frozen_bus = eeh_pe_bus_get(pe);
if (!frozen_bus) {
pr_err("%s: Cannot find PCI bus for PHB#%d-PE#%x\n",
__func__, pe->phb->global_number, pe->addr);
return;
}
pe->freeze_count++;
if (pe->freeze_count > EEH_MAX_ALLOWED_FREEZES)
goto excess_failures;
pr_warning("EEH: This PCI device has failed %d times in the last hour\n",
pe->freeze_count);
/* 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.
*/
eeh_pe_dev_traverse(pe, eeh_report_error, &result);
/* Get the current PCI slot state. This can take a long time,
* sometimes over 3 seconds for certain systems.
*/
rc = eeh_ops->wait_state(pe, MAX_WAIT_FOR_RECOVERY*1000);
if (rc < 0 || rc == EEH_STATE_NOT_SUPPORT) {
printk(KERN_WARNING "EEH: Permanent failure\n");
goto hard_fail;
}
/* Since rtas may enable MMIO when posting the error log,
* don't post the error log until after all dev drivers
* have been informed.
*/
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) {
rc = eeh_reset_device(pe, frozen_bus);
if (rc) {
printk(KERN_WARNING "EEH: Unable to reset, rc=%d\n", rc);
goto hard_fail;
}
}
/* If all devices reported they can proceed, then re-enable MMIO */
if (result == PCI_ERS_RESULT_CAN_RECOVER) {
rc = eeh_pci_enable(pe, EEH_OPT_THAW_MMIO);
if (rc < 0)
goto hard_fail;
if (rc) {
result = PCI_ERS_RESULT_NEED_RESET;
} else {
result = PCI_ERS_RESULT_NONE;
eeh_pe_dev_traverse(pe, eeh_report_mmio_enabled, &result);
}
}
/* If all devices reported they can proceed, then re-enable DMA */
if (result == PCI_ERS_RESULT_CAN_RECOVER) {
rc = eeh_pci_enable(pe, EEH_OPT_THAW_DMA);
if (rc < 0)
goto hard_fail;
if (rc)
result = PCI_ERS_RESULT_NEED_RESET;
else
result = PCI_ERS_RESULT_RECOVERED;
}
/* If any device has a hard failure, then shut off everything. */
if (result == PCI_ERS_RESULT_DISCONNECT) {
printk(KERN_WARNING "EEH: Device driver gave up\n");
goto hard_fail;
}
/* If any device called out for a reset, then reset the slot */
if (result == PCI_ERS_RESULT_NEED_RESET) {
rc = eeh_reset_device(pe, NULL);
if (rc) {
printk(KERN_WARNING "EEH: Cannot reset, rc=%d\n", rc);
goto hard_fail;
}
result = PCI_ERS_RESULT_NONE;
eeh_pe_dev_traverse(pe, eeh_report_reset, &result);
}
/* All devices should claim they have recovered by now. */
if ((result != PCI_ERS_RESULT_RECOVERED) &&
(result != PCI_ERS_RESULT_NONE)) {
printk(KERN_WARNING "EEH: Not recovered\n");
goto hard_fail;
}
/* Tell all device drivers that they can resume operations */
eeh_pe_dev_traverse(pe, eeh_report_resume, NULL);
return;
excess_failures:
/*
* 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: PHB#%d-PE#%x has failed %d times in the\n"
"last hour and has been permanently disabled.\n"
"Please try reseating or replacing it.\n",
pe->phb->global_number, pe->addr,
pe->freeze_count);
goto perm_error;
hard_fail:
pr_err("EEH: Unable to recover from failure from PHB#%d-PE#%x.\n"
"Please try reseating or replacing it\n",
pe->phb->global_number, pe->addr);
perm_error:
eeh_slot_error_detail(pe, EEH_LOG_PERM);
/* Notify all devices that they're about to go down. */
eeh_pe_dev_traverse(pe, eeh_report_failure, NULL);
/* Shut down the device drivers for good. */
if (frozen_bus)
pcibios_remove_pci_devices(frozen_bus);
}
