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android_kernel_xiaomi_sm8350/arch/powerpc/platforms/pseries/eeh.c
Mike Mason f36c5227cd powerpc/eeh: Don't panic when EEH_MAX_FAILS is exceeded 
This patch changes the EEH_MAX_FAILS action from panic to printing an
error message.  Panicking under under this condition is too harsh.
Although performance will be affected and the device may not recover,
the system is still running, which at the very least should allow for a
more graceful shutdown. The patch also removes the msleep() within a
spinlock, which can lead to a deadlock and is not recommended.

Signed-off-by: Mike Mason <mmlnx@us.ibm.com>
Acked-by: Linas Vepstas <linasvepstas@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2008-07-22 10:39:37 +10:00

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/*
* eeh.c
* Copyright IBM Corporation 2001, 2005, 2006
* Copyright Dave Engebretsen & Todd Inglett 2001
* Copyright Linas Vepstas 2005, 2006
*
* 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. 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Please address comments and feedback to Linas Vepstas <linas@austin.ibm.com>
*/
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/pci.h>
#include <linux/proc_fs.h>
#include <linux/rbtree.h>
#include <linux/seq_file.h>
#include <linux/spinlock.h>
#include <linux/of.h>
#include <asm/atomic.h>
#include <asm/eeh.h>
#include <asm/eeh_event.h>
#include <asm/io.h>
#include <asm/machdep.h>
#include <asm/ppc-pci.h>
#include <asm/rtas.h>
/** Overview:
* EEH, or "Extended Error Handling" is a PCI bridge technology for
* dealing with PCI bus errors that can't be dealt with within the
* usual PCI framework, except by check-stopping the CPU. Systems
* that are designed for high-availability/reliability cannot afford
* to crash due to a "mere" PCI error, thus the need for EEH.
* An EEH-capable bridge operates by converting a detected error
* into a "slot freeze", taking the PCI adapter off-line, making
* the slot behave, from the OS'es point of view, as if the slot
* were "empty": all reads return 0xff's and all writes are silently
* ignored. EEH slot isolation events can be triggered by parity
* errors on the address or data busses (e.g. during posted writes),
* which in turn might be caused by low voltage on the bus, dust,
* vibration, humidity, radioactivity or plain-old failed hardware.
*
* Note, however, that one of the leading causes of EEH slot
* freeze events are buggy device drivers, buggy device microcode,
* or buggy device hardware. This is because any attempt by the
* device to bus-master data to a memory address that is not
* assigned to the device will trigger a slot freeze. (The idea
* is to prevent devices-gone-wild from corrupting system memory).
* Buggy hardware/drivers will have a miserable time co-existing
* with EEH.
*
* Ideally, a PCI device driver, when suspecting that an isolation
* event has occured (e.g. by reading 0xff's), will then ask EEH
* whether this is the case, and then take appropriate steps to
* reset the PCI slot, the PCI device, and then resume operations.
* However, until that day, the checking is done here, with the
* eeh_check_failure() routine embedded in the MMIO macros. If
* the slot is found to be isolated, an "EEH Event" is synthesized
* and sent out for processing.
*/
/* If a device driver keeps reading an MMIO register in an interrupt
* handler after a slot isolation event, it might be broken.
* This sets the threshold for how many read attempts we allow
* before printing an error message.
*/
#define EEH_MAX_FAILS 2100000
/* Time to wait for a PCI slot to report status, in milliseconds */
#define PCI_BUS_RESET_WAIT_MSEC (60*1000)
/* RTAS tokens */
static int ibm_set_eeh_option;
static int ibm_set_slot_reset;
static int ibm_read_slot_reset_state;
static int ibm_read_slot_reset_state2;
static int ibm_slot_error_detail;
static int ibm_get_config_addr_info;
static int ibm_get_config_addr_info2;
static int ibm_configure_bridge;
int eeh_subsystem_enabled;
EXPORT_SYMBOL(eeh_subsystem_enabled);
/* Lock to avoid races due to multiple reports of an error */
static DEFINE_SPINLOCK(confirm_error_lock);
/* Buffer for reporting slot-error-detail rtas calls. Its here
* in BSS, and not dynamically alloced, so that it ends up in
* RMO where RTAS can access it.
*/
static unsigned char slot_errbuf[RTAS_ERROR_LOG_MAX];
static DEFINE_SPINLOCK(slot_errbuf_lock);
static int eeh_error_buf_size;
/* Buffer for reporting pci register dumps. Its here in BSS, and
* not dynamically alloced, so that it ends up in RMO where RTAS
* can access it.
*/
#define EEH_PCI_REGS_LOG_LEN 4096
static unsigned char pci_regs_buf[EEH_PCI_REGS_LOG_LEN];
/* System monitoring statistics */
static unsigned long no_device;
static unsigned long no_dn;
static unsigned long no_cfg_addr;
static unsigned long ignored_check;
static unsigned long total_mmio_ffs;
static unsigned long false_positives;
static unsigned long slot_resets;
#define IS_BRIDGE(class_code) (((class_code)<<16) == PCI_BASE_CLASS_BRIDGE)
/* --------------------------------------------------------------- */
/* Below lies the EEH event infrastructure */
static void rtas_slot_error_detail(struct pci_dn *pdn, int severity,
char *driver_log, size_t loglen)
{
int config_addr;
unsigned long flags;
int rc;
/* Log the error with the rtas logger */
spin_lock_irqsave(&slot_errbuf_lock, flags);
memset(slot_errbuf, 0, eeh_error_buf_size);
/* Use PE configuration address, if present */
config_addr = pdn->eeh_config_addr;
if (pdn->eeh_pe_config_addr)
config_addr = pdn->eeh_pe_config_addr;
rc = rtas_call(ibm_slot_error_detail,
8, 1, NULL, config_addr,
BUID_HI(pdn->phb->buid),
BUID_LO(pdn->phb->buid),
virt_to_phys(driver_log), loglen,
virt_to_phys(slot_errbuf),
eeh_error_buf_size,
severity);
if (rc == 0)
log_error(slot_errbuf, ERR_TYPE_RTAS_LOG, 0);
spin_unlock_irqrestore(&slot_errbuf_lock, flags);
}
/**
* gather_pci_data - copy assorted PCI config space registers to buff
* @pdn: device to report data for
* @buf: point to buffer in which to log
* @len: amount of room in buffer
*
* This routine captures assorted PCI configuration space data,
* and puts them into a buffer for RTAS error logging.
*/
static size_t gather_pci_data(struct pci_dn *pdn, char * buf, size_t len)
{
struct pci_dev *dev = pdn->pcidev;
u32 cfg;
int cap, i;
int n = 0;
n += scnprintf(buf+n, len-n, "%s\n", pdn->node->full_name);
printk(KERN_WARNING "EEH: of node=%s\n", pdn->node->full_name);
rtas_read_config(pdn, PCI_VENDOR_ID, 4, &cfg);
n += scnprintf(buf+n, len-n, "dev/vend:%08x\n", cfg);
printk(KERN_WARNING "EEH: PCI device/vendor: %08x\n", cfg);
rtas_read_config(pdn, PCI_COMMAND, 4, &cfg);
n += scnprintf(buf+n, len-n, "cmd/stat:%x\n", cfg);
printk(KERN_WARNING "EEH: PCI cmd/status register: %08x\n", cfg);
if (!dev) {
printk(KERN_WARNING "EEH: no PCI device for this of node\n");
return n;
}
/* Gather bridge-specific registers */
if (dev->class >> 16 == PCI_BASE_CLASS_BRIDGE) {
rtas_read_config(pdn, PCI_SEC_STATUS, 2, &cfg);
n += scnprintf(buf+n, len-n, "sec stat:%x\n", cfg);
printk(KERN_WARNING "EEH: Bridge secondary status: %04x\n", cfg);
rtas_read_config(pdn, PCI_BRIDGE_CONTROL, 2, &cfg);
n += scnprintf(buf+n, len-n, "brdg ctl:%x\n", cfg);
printk(KERN_WARNING "EEH: Bridge control: %04x\n", cfg);
}
/* Dump out the PCI-X command and status regs */
cap = pci_find_capability(dev, PCI_CAP_ID_PCIX);
if (cap) {
rtas_read_config(pdn, cap, 4, &cfg);
n += scnprintf(buf+n, len-n, "pcix-cmd:%x\n", cfg);
printk(KERN_WARNING "EEH: PCI-X cmd: %08x\n", cfg);
rtas_read_config(pdn, cap+4, 4, &cfg);
n += scnprintf(buf+n, len-n, "pcix-stat:%x\n", cfg);
printk(KERN_WARNING "EEH: PCI-X status: %08x\n", cfg);
}
/* If PCI-E capable, dump PCI-E cap 10, and the AER */
cap = pci_find_capability(dev, PCI_CAP_ID_EXP);
if (cap) {
n += scnprintf(buf+n, len-n, "pci-e cap10:\n");
printk(KERN_WARNING
"EEH: PCI-E capabilities and status follow:\n");
for (i=0; i<=8; i++) {
rtas_read_config(pdn, cap+4*i, 4, &cfg);
n += scnprintf(buf+n, len-n, "%02x:%x\n", 4*i, cfg);
printk(KERN_WARNING "EEH: PCI-E %02x: %08x\n", i, cfg);
}
cap = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
if (cap) {
n += scnprintf(buf+n, len-n, "pci-e AER:\n");
printk(KERN_WARNING
"EEH: PCI-E AER capability register set follows:\n");
for (i=0; i<14; i++) {
rtas_read_config(pdn, cap+4*i, 4, &cfg);
n += scnprintf(buf+n, len-n, "%02x:%x\n", 4*i, cfg);
printk(KERN_WARNING "EEH: PCI-E AER %02x: %08x\n", i, cfg);
}
}
}
/* Gather status on devices under the bridge */
if (dev->class >> 16 == PCI_BASE_CLASS_BRIDGE) {
struct device_node *dn;
for_each_child_of_node(pdn->node, dn) {
pdn = PCI_DN(dn);
if (pdn)
n += gather_pci_data(pdn, buf+n, len-n);
}
}
return n;
}
void eeh_slot_error_detail(struct pci_dn *pdn, int severity)
{
size_t loglen = 0;
pci_regs_buf[0] = 0;
rtas_pci_enable(pdn, EEH_THAW_MMIO);
loglen = gather_pci_data(pdn, pci_regs_buf, EEH_PCI_REGS_LOG_LEN);
rtas_slot_error_detail(pdn, severity, pci_regs_buf, loglen);
}
/**
* read_slot_reset_state - Read the reset state of a device node's slot
* @dn: device node to read
* @rets: array to return results in
*/
static int read_slot_reset_state(struct pci_dn *pdn, int rets[])
{
int token, outputs;
int config_addr;
if (ibm_read_slot_reset_state2 != RTAS_UNKNOWN_SERVICE) {
token = ibm_read_slot_reset_state2;
outputs = 4;
} else {
token = ibm_read_slot_reset_state;
rets[2] = 0; /* fake PE Unavailable info */
outputs = 3;
}
/* Use PE configuration address, if present */
config_addr = pdn->eeh_config_addr;
if (pdn->eeh_pe_config_addr)
config_addr = pdn->eeh_pe_config_addr;
return rtas_call(token, 3, outputs, rets, config_addr,
BUID_HI(pdn->phb->buid), BUID_LO(pdn->phb->buid));
}
/**
* eeh_wait_for_slot_status - returns error status of slot
* @pdn pci device node
* @max_wait_msecs maximum number to millisecs to wait
*
* Return negative value if a permanent error, else return
* Partition Endpoint (PE) status value.
*
* If @max_wait_msecs is positive, then this routine will
* sleep until a valid status can be obtained, or until
* the max allowed wait time is exceeded, in which case
* a -2 is returned.
*/
int
eeh_wait_for_slot_status(struct pci_dn *pdn, int max_wait_msecs)
{
int rc;
int rets[3];
int mwait;
while (1) {
rc = read_slot_reset_state(pdn, rets);
if (rc) return rc;
if (rets[1] == 0) return -1; /* EEH is not supported */
if (rets[0] != 5) return rets[0]; /* return actual status */
if (rets[2] == 0) return -1; /* permanently unavailable */
if (max_wait_msecs <= 0) break;
mwait = rets[2];
if (mwait <= 0) {
printk (KERN_WARNING
"EEH: Firmware returned bad wait value=%d\n", mwait);
mwait = 1000;
} else if (mwait > 300*1000) {
printk (KERN_WARNING
"EEH: Firmware is taking too long, time=%d\n", mwait);
mwait = 300*1000;
}
max_wait_msecs -= mwait;
msleep (mwait);
}
printk(KERN_WARNING "EEH: Timed out waiting for slot status\n");
return -2;
}
/**
* eeh_token_to_phys - convert EEH address token to phys address
* @token i/o token, should be address in the form 0xA....
*/
static inline unsigned long eeh_token_to_phys(unsigned long token)
{
pte_t *ptep;
unsigned long pa;
ptep = find_linux_pte(init_mm.pgd, token);
if (!ptep)
return token;
pa = pte_pfn(*ptep) << PAGE_SHIFT;
return pa | (token & (PAGE_SIZE-1));
}
/**
* Return the "partitionable endpoint" (pe) under which this device lies
*/
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;
}
/** Mark all devices that are children of this device as failed.
* Mark the device driver too, so that it can see the failure
* immediately; this is critical, since some drivers poll
* status registers in interrupts ... If a driver is polling,
* and the slot is frozen, then the driver can deadlock in
* an interrupt context, which is bad.
*/
static void __eeh_mark_slot(struct device_node *parent, int mode_flag)
{
struct device_node *dn;
for_each_child_of_node(parent, dn) {
if (PCI_DN(dn)) {
/* Mark the pci device driver too */
struct pci_dev *dev = PCI_DN(dn)->pcidev;
PCI_DN(dn)->eeh_mode |= mode_flag;
if (dev && dev->driver)
dev->error_state = pci_channel_io_frozen;
__eeh_mark_slot(dn, mode_flag);
}
}
}
void eeh_mark_slot (struct device_node *dn, int mode_flag)
{
struct pci_dev *dev;
dn = find_device_pe (dn);
/* Back up one, since config addrs might be shared */
if (!pcibios_find_pci_bus(dn) && PCI_DN(dn->parent))
dn = dn->parent;
PCI_DN(dn)->eeh_mode |= mode_flag;
/* Mark the pci device too */
dev = PCI_DN(dn)->pcidev;
if (dev)
dev->error_state = pci_channel_io_frozen;
__eeh_mark_slot(dn, mode_flag);
}
static void __eeh_clear_slot(struct device_node *parent, int mode_flag)
{
struct device_node *dn;
for_each_child_of_node(parent, dn) {
if (PCI_DN(dn)) {
PCI_DN(dn)->eeh_mode &= ~mode_flag;
PCI_DN(dn)->eeh_check_count = 0;
__eeh_clear_slot(dn, mode_flag);
}
}
}
void eeh_clear_slot (struct device_node *dn, int mode_flag)
{
unsigned long flags;
spin_lock_irqsave(&confirm_error_lock, flags);
dn = find_device_pe (dn);
/* Back up one, since config addrs might be shared */
if (!pcibios_find_pci_bus(dn) && PCI_DN(dn->parent))
dn = dn->parent;
PCI_DN(dn)->eeh_mode &= ~mode_flag;
PCI_DN(dn)->eeh_check_count = 0;
__eeh_clear_slot(dn, mode_flag);
spin_unlock_irqrestore(&confirm_error_lock, flags);
}
/**
* eeh_dn_check_failure - check if all 1's data is due to EEH slot freeze
* @dn device node
* @dev pci device, if known
*
* Check for an EEH failure for the given device node. Call this
* routine if the result of a read was all 0xff's and you want to
* find out if this is due to an EEH slot freeze. This routine
* will query firmware for the EEH status.
*
* Returns 0 if there has not been an EEH error; otherwise returns
* a non-zero value and queues up a slot isolation event notification.
*
* It is safe to call this routine in an interrupt context.
*/
int eeh_dn_check_failure(struct device_node *dn, struct pci_dev *dev)
{
int ret;
int rets[3];
unsigned long flags;
struct pci_dn *pdn;
int rc = 0;
const char *location;
total_mmio_ffs++;
if (!eeh_subsystem_enabled)
return 0;
if (!dn) {
no_dn++;
return 0;
}
dn = find_device_pe(dn);
pdn = PCI_DN(dn);
/* Access to IO BARs might get this far and still not want checking. */
if (!(pdn->eeh_mode & EEH_MODE_SUPPORTED) ||
pdn->eeh_mode & EEH_MODE_NOCHECK) {
ignored_check++;
#ifdef DEBUG
printk ("EEH:ignored check (%x) for %s %s\n",
pdn->eeh_mode, pci_name (dev), dn->full_name);
#endif
return 0;
}
if (!pdn->eeh_config_addr && !pdn->eeh_pe_config_addr) {
no_cfg_addr++;
return 0;
}
/* If we already have a pending isolation event for this
* slot, we know it's bad already, we don't need to check.
* Do this checking under a lock; as multiple PCI devices
* in one slot might report errors simultaneously, and we
* only want one error recovery routine running.
*/
spin_lock_irqsave(&confirm_error_lock, flags);
rc = 1;
if (pdn->eeh_mode & EEH_MODE_ISOLATED) {
pdn->eeh_check_count ++;
if (pdn->eeh_check_count % EEH_MAX_FAILS == 0) {
location = of_get_property(dn, "ibm,loc-code", NULL);
printk (KERN_ERR "EEH: %d reads ignored for recovering device at "
"location=%s driver=%s pci addr=%s\n",
pdn->eeh_check_count, location,
dev->driver->name, pci_name(dev));
printk (KERN_ERR "EEH: Might be infinite loop in %s driver\n",
dev->driver->name);
dump_stack();
}
goto dn_unlock;
}
/*
* Now test for an EEH failure. This is VERY expensive.
* Note that the eeh_config_addr may be a parent device
* in the case of a device behind a bridge, or it may be
* function zero of a multi-function device.
* In any case they must share a common PHB.
*/
ret = read_slot_reset_state(pdn, rets);
/* If the call to firmware failed, punt */
if (ret != 0) {
printk(KERN_WARNING "EEH: read_slot_reset_state() failed; rc=%d dn=%s\n",
ret, dn->full_name);
false_positives++;
pdn->eeh_false_positives ++;
rc = 0;
goto dn_unlock;
}
/* Note that config-io to empty slots may fail;
* they are empty when they don't have children. */
if ((rets[0] == 5) && (rets[2] == 0) && (dn->child == NULL)) {
false_positives++;
pdn->eeh_false_positives ++;
rc = 0;
goto dn_unlock;
}
/* If EEH is not supported on this device, punt. */
if (rets[1] != 1) {
printk(KERN_WARNING "EEH: event on unsupported device, rc=%d dn=%s\n",
ret, dn->full_name);
false_positives++;
pdn->eeh_false_positives ++;
rc = 0;
goto dn_unlock;
}
/* If not the kind of error we know about, punt. */
if (rets[0] != 1 && rets[0] != 2 && rets[0] != 4 && rets[0] != 5) {
false_positives++;
pdn->eeh_false_positives ++;
rc = 0;
goto dn_unlock;
}
slot_resets++;
/* Avoid repeated reports of this failure, including problems
* with other functions on this device, and functions under
* bridges. */
eeh_mark_slot (dn, EEH_MODE_ISOLATED);
spin_unlock_irqrestore(&confirm_error_lock, flags);
eeh_send_failure_event (dn, dev);
/* 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. */
dump_stack();
return 1;
dn_unlock:
spin_unlock_irqrestore(&confirm_error_lock, flags);
return rc;
}
EXPORT_SYMBOL_GPL(eeh_dn_check_failure);
/**
* eeh_check_failure - check if all 1's data is due to EEH slot freeze
* @token i/o token, should be address in the form 0xA....
* @val value, should be all 1's (XXX why do we need this arg??)
*
* Check for an EEH failure at the given token address. Call this
* routine if the result of a read was all 0xff's and you want to
* find out if this is due to an EEH slot freeze event. This routine
* will query firmware for the EEH status.
*
* Note this routine is safe to call in an interrupt context.
*/
unsigned long eeh_check_failure(const volatile void __iomem *token, unsigned long val)
{
unsigned long addr;
struct pci_dev *dev;
struct device_node *dn;
/* Finding the phys addr + pci device; this is pretty quick. */
addr = eeh_token_to_phys((unsigned long __force) token);
dev = pci_get_device_by_addr(addr);
if (!dev) {
no_device++;
return val;
}
dn = pci_device_to_OF_node(dev);
eeh_dn_check_failure (dn, dev);
pci_dev_put(dev);
return val;
}
EXPORT_SYMBOL(eeh_check_failure);
/* ------------------------------------------------------------- */
/* The code below deals with error recovery */
/**
* rtas_pci_enable - enable MMIO or DMA transfers for this slot
* @pdn pci device node
*/
int
rtas_pci_enable(struct pci_dn *pdn, int function)
{
int config_addr;
int rc;
/* Use PE configuration address, if present */
config_addr = pdn->eeh_config_addr;
if (pdn->eeh_pe_config_addr)
config_addr = pdn->eeh_pe_config_addr;
rc = rtas_call(ibm_set_eeh_option, 4, 1, NULL,
config_addr,
BUID_HI(pdn->phb->buid),
BUID_LO(pdn->phb->buid),
function);
if (rc)
printk(KERN_WARNING "EEH: Unexpected state change %d, err=%d dn=%s\n",
function, rc, pdn->node->full_name);
rc = eeh_wait_for_slot_status (pdn, PCI_BUS_RESET_WAIT_MSEC);
if ((rc == 4) && (function == EEH_THAW_MMIO))
return 0;
return rc;
}
/**
* rtas_pci_slot_reset - raises/lowers the pci #RST line
* @pdn pci device node
* @state: 1/0 to raise/lower the #RST
*
* Clear the EEH-frozen condition on a slot. This routine
* asserts the PCI #RST line if the 'state' argument is '1',
* and drops the #RST line if 'state is '0'. This routine is
* safe to call in an interrupt context.
*
*/
static void
rtas_pci_slot_reset(struct pci_dn *pdn, int state)
{
int config_addr;
int rc;
BUG_ON (pdn==NULL);
if (!pdn->phb) {
printk (KERN_WARNING "EEH: in slot reset, device node %s has no phb\n",
pdn->node->full_name);
return;
}
/* Use PE configuration address, if present */
config_addr = pdn->eeh_config_addr;
if (pdn->eeh_pe_config_addr)
config_addr = pdn->eeh_pe_config_addr;
rc = rtas_call(ibm_set_slot_reset,4,1, NULL,
config_addr,
BUID_HI(pdn->phb->buid),
BUID_LO(pdn->phb->buid),
state);
if (rc)
printk (KERN_WARNING "EEH: Unable to reset the failed slot,"
" (%d) #RST=%d dn=%s\n",
rc, state, pdn->node->full_name);
}
/**
* pcibios_set_pcie_slot_reset - Set PCI-E reset state
* @dev: pci device struct
* @state: reset state to enter
*
* Return value:
* 0 if success
**/
int pcibios_set_pcie_reset_state(struct pci_dev *dev, enum pcie_reset_state state)
{
struct device_node *dn = pci_device_to_OF_node(dev);
struct pci_dn *pdn = PCI_DN(dn);
switch (state) {
case pcie_deassert_reset:
rtas_pci_slot_reset(pdn, 0);
break;
case pcie_hot_reset:
rtas_pci_slot_reset(pdn, 1);
break;
case pcie_warm_reset:
rtas_pci_slot_reset(pdn, 3);
break;
default:
return -EINVAL;
};
return 0;
}
/**
* rtas_set_slot_reset -- assert the pci #RST line for 1/4 second
* @pdn: pci device node to be reset.
*
* Return 0 if success, else a non-zero value.
*/
static void __rtas_set_slot_reset(struct pci_dn *pdn)
{
rtas_pci_slot_reset (pdn, 1);
/* The PCI bus requires that the reset be held high for at least
* a 100 milliseconds. We wait a bit longer 'just in case'. */
#define PCI_BUS_RST_HOLD_TIME_MSEC 250
msleep (PCI_BUS_RST_HOLD_TIME_MSEC);
/* We might get hit with another EEH freeze as soon as the
* pci slot reset line is dropped. Make sure we don't miss
* these, and clear the flag now. */
eeh_clear_slot (pdn->node, EEH_MODE_ISOLATED);
rtas_pci_slot_reset (pdn, 0);
/* After a PCI slot has been reset, the PCI Express spec requires
* a 1.5 second idle time for the bus to stabilize, before starting
* up traffic. */
#define PCI_BUS_SETTLE_TIME_MSEC 1800
msleep (PCI_BUS_SETTLE_TIME_MSEC);
}
int rtas_set_slot_reset(struct pci_dn *pdn)
{
int i, rc;
/* Take three shots at resetting the bus */
for (i=0; i<3; i++) {
__rtas_set_slot_reset(pdn);
rc = eeh_wait_for_slot_status(pdn, PCI_BUS_RESET_WAIT_MSEC);
if (rc == 0)
return 0;
if (rc < 0) {
printk(KERN_ERR "EEH: unrecoverable slot failure %s\n",
pdn->node->full_name);
return -1;
}
printk(KERN_ERR "EEH: bus reset %d failed on slot %s, rc=%d\n",
i+1, pdn->node->full_name, rc);
}
return -1;
}
/* ------------------------------------------------------- */
/** Save and restore of PCI BARs
*
* Although firmware will set up BARs during boot, it doesn't
* set up device BAR's after a device reset, although it will,
* if requested, set up bridge configuration. Thus, we need to
* configure the PCI devices ourselves.
*/
/**
* __restore_bars - Restore the Base Address Registers
* @pdn: pci device node
*
* Loads the PCI configuration space base address registers,
* the expansion ROM base address, the latency timer, and etc.
* from the saved values in the device node.
*/
static inline void __restore_bars (struct pci_dn *pdn)
{
int i;
u32 cmd;
if (NULL==pdn->phb) return;
for (i=4; i<10; i++) {
rtas_write_config(pdn, i*4, 4, pdn->config_space[i]);
}
/* 12 == Expansion ROM Address */
rtas_write_config(pdn, 12*4, 4, pdn->config_space[12]);
#define BYTE_SWAP(OFF) (8*((OFF)/4)+3-(OFF))
#define SAVED_BYTE(OFF) (((u8 *)(pdn->config_space))[BYTE_SWAP(OFF)])
rtas_write_config (pdn, PCI_CACHE_LINE_SIZE, 1,
SAVED_BYTE(PCI_CACHE_LINE_SIZE));
rtas_write_config (pdn, PCI_LATENCY_TIMER, 1,
SAVED_BYTE(PCI_LATENCY_TIMER));
/* max latency, min grant, interrupt pin and line */
rtas_write_config(pdn, 15*4, 4, pdn->config_space[15]);
/* Restore PERR & SERR bits, some devices require it,
don't touch the other command bits */
rtas_read_config(pdn, PCI_COMMAND, 4, &cmd);
if (pdn->config_space[1] & PCI_COMMAND_PARITY)
cmd |= PCI_COMMAND_PARITY;
else
cmd &= ~PCI_COMMAND_PARITY;
if (pdn->config_space[1] & PCI_COMMAND_SERR)
cmd |= PCI_COMMAND_SERR;
else
cmd &= ~PCI_COMMAND_SERR;
rtas_write_config(pdn, PCI_COMMAND, 4, cmd);
}
/**
* eeh_restore_bars - restore the PCI config space info
*
* This routine performs a recursive walk to the children
* of this device as well.
*/
void eeh_restore_bars(struct pci_dn *pdn)
{
struct device_node *dn;
if (!pdn)
return;
if ((pdn->eeh_mode & EEH_MODE_SUPPORTED) && !IS_BRIDGE(pdn->class_code))
__restore_bars (pdn);
for_each_child_of_node(pdn->node, dn)
eeh_restore_bars (PCI_DN(dn));
}
/**
* eeh_save_bars - save device bars
*
* Save the values of the device bars. Unlike the restore
* routine, this routine is *not* recursive. This is because
* PCI devices are added individuallly; but, for the restore,
* an entire slot is reset at a time.
*/
static void eeh_save_bars(struct pci_dn *pdn)
{
int i;
if (!pdn )
return;
for (i = 0; i < 16; i++)
rtas_read_config(pdn, i * 4, 4, &pdn->config_space[i]);
}
void
rtas_configure_bridge(struct pci_dn *pdn)
{
int config_addr;
int rc;
/* Use PE configuration address, if present */
config_addr = pdn->eeh_config_addr;
if (pdn->eeh_pe_config_addr)
config_addr = pdn->eeh_pe_config_addr;
rc = rtas_call(ibm_configure_bridge,3,1, NULL,
config_addr,
BUID_HI(pdn->phb->buid),
BUID_LO(pdn->phb->buid));
if (rc) {
printk (KERN_WARNING "EEH: Unable to configure device bridge (%d) for %s\n",
rc, pdn->node->full_name);
}
}
/* ------------------------------------------------------------- */
/* The code below deals with enabling EEH for devices during the
* early boot sequence. EEH must be enabled before any PCI probing
* can be done.
*/
#define EEH_ENABLE 1
struct eeh_early_enable_info {
unsigned int buid_hi;
unsigned int buid_lo;
};
static int get_pe_addr (int config_addr,
struct eeh_early_enable_info *info)
{
unsigned int rets[3];
int ret;
/* Use latest config-addr token on power6 */
if (ibm_get_config_addr_info2 != RTAS_UNKNOWN_SERVICE) {
/* Make sure we have a PE in hand */
ret = rtas_call (ibm_get_config_addr_info2, 4, 2, rets,
config_addr, info->buid_hi, info->buid_lo, 1);
if (ret || (rets[0]==0))
return 0;
ret = rtas_call (ibm_get_config_addr_info2, 4, 2, rets,
config_addr, info->buid_hi, info->buid_lo, 0);
if (ret)
return 0;
return rets[0];
}
/* Use older config-addr token on power5 */
if (ibm_get_config_addr_info != RTAS_UNKNOWN_SERVICE) {
ret = rtas_call (ibm_get_config_addr_info, 4, 2, rets,
config_addr, info->buid_hi, info->buid_lo, 0);
if (ret)
return 0;
return rets[0];
}
return 0;
}
/* Enable eeh for the given device node. */
static void *early_enable_eeh(struct device_node *dn, void *data)
{
unsigned int rets[3];
struct eeh_early_enable_info *info = data;
int ret;
const u32 *class_code = of_get_property(dn, "class-code", NULL);
const u32 *vendor_id = of_get_property(dn, "vendor-id", NULL);
const u32 *device_id = of_get_property(dn, "device-id", NULL);
const u32 *regs;
int enable;
struct pci_dn *pdn = PCI_DN(dn);
pdn->class_code = 0;
pdn->eeh_mode = 0;
pdn->eeh_check_count = 0;
pdn->eeh_freeze_count = 0;
pdn->eeh_false_positives = 0;
if (!of_device_is_available(dn))
return NULL;
/* Ignore bad nodes. */
if (!class_code || !vendor_id || !device_id)
return NULL;
/* There is nothing to check on PCI to ISA bridges */
if (dn->type && !strcmp(dn->type, "isa")) {
pdn->eeh_mode |= EEH_MODE_NOCHECK;
return NULL;
}
pdn->class_code = *class_code;
/* Ok... see if this device supports EEH. Some do, some don't,
* and the only way to find out is to check each and every one. */
regs = of_get_property(dn, "reg", NULL);
if (regs) {
/* First register entry is addr (00BBSS00) */
/* Try to enable eeh */
ret = rtas_call(ibm_set_eeh_option, 4, 1, NULL,
regs[0], info->buid_hi, info->buid_lo,
EEH_ENABLE);
enable = 0;
if (ret == 0) {
pdn->eeh_config_addr = regs[0];
/* If the newer, better, ibm,get-config-addr-info is supported,
* then use that instead. */
pdn->eeh_pe_config_addr = get_pe_addr(pdn->eeh_config_addr, info);
/* Some older systems (Power4) allow the
* ibm,set-eeh-option call to succeed even on nodes
* where EEH is not supported. Verify support
* explicitly. */
ret = read_slot_reset_state(pdn, rets);
if ((ret == 0) && (rets[1] == 1))
enable = 1;
}
if (enable) {
eeh_subsystem_enabled = 1;
pdn->eeh_mode |= EEH_MODE_SUPPORTED;
#ifdef DEBUG
printk(KERN_DEBUG "EEH: %s: eeh enabled, config=%x pe_config=%x\n",
dn->full_name, pdn->eeh_config_addr, pdn->eeh_pe_config_addr);
#endif
} else {
/* This device doesn't support EEH, but it may have an
* EEH parent, in which case we mark it as supported. */
if (dn->parent && PCI_DN(dn->parent)
&& (PCI_DN(dn->parent)->eeh_mode & EEH_MODE_SUPPORTED)) {
/* Parent supports EEH. */
pdn->eeh_mode |= EEH_MODE_SUPPORTED;
pdn->eeh_config_addr = PCI_DN(dn->parent)->eeh_config_addr;
return NULL;
}
}
} else {
printk(KERN_WARNING "EEH: %s: unable to get reg property.\n",
dn->full_name);
}
eeh_save_bars(pdn);
return NULL;
}
/*
* Initialize EEH by trying to enable it for all of the adapters in the system.
* As a side effect we can determine here if eeh is supported at all.
* Note that we leave EEH on so failed config cycles won't cause a machine
* check. If a user turns off EEH for a particular adapter they are really
* telling Linux to ignore errors. Some hardware (e.g. POWER5) won't
* grant access to a slot if EEH isn't enabled, and so we always enable
* EEH for all slots/all devices.
*
* The eeh-force-off option disables EEH checking globally, for all slots.
* Even if force-off is set, the EEH hardware is still enabled, so that
* newer systems can boot.
*/
void __init eeh_init(void)
{
struct device_node *phb, *np;
struct eeh_early_enable_info info;
spin_lock_init(&confirm_error_lock);
spin_lock_init(&slot_errbuf_lock);
np = of_find_node_by_path("/rtas");
if (np == NULL)
return;
ibm_set_eeh_option = rtas_token("ibm,set-eeh-option");
ibm_set_slot_reset = rtas_token("ibm,set-slot-reset");
ibm_read_slot_reset_state2 = rtas_token("ibm,read-slot-reset-state2");
ibm_read_slot_reset_state = rtas_token("ibm,read-slot-reset-state");
ibm_slot_error_detail = rtas_token("ibm,slot-error-detail");
ibm_get_config_addr_info = rtas_token("ibm,get-config-addr-info");
ibm_get_config_addr_info2 = rtas_token("ibm,get-config-addr-info2");
ibm_configure_bridge = rtas_token ("ibm,configure-bridge");
if (ibm_set_eeh_option == RTAS_UNKNOWN_SERVICE)
return;
eeh_error_buf_size = rtas_token("rtas-error-log-max");
if (eeh_error_buf_size == RTAS_UNKNOWN_SERVICE) {
eeh_error_buf_size = 1024;
}
if (eeh_error_buf_size > RTAS_ERROR_LOG_MAX) {
printk(KERN_WARNING "EEH: rtas-error-log-max is bigger than allocated "
"buffer ! (%d vs %d)", eeh_error_buf_size, RTAS_ERROR_LOG_MAX);
eeh_error_buf_size = RTAS_ERROR_LOG_MAX;
}
/* Enable EEH for all adapters. Note that eeh requires buid's */
for (phb = of_find_node_by_name(NULL, "pci"); phb;
phb = of_find_node_by_name(phb, "pci")) {
unsigned long buid;
buid = get_phb_buid(phb);
if (buid == 0 || PCI_DN(phb) == NULL)
continue;
info.buid_lo = BUID_LO(buid);
info.buid_hi = BUID_HI(buid);
traverse_pci_devices(phb, early_enable_eeh, &info);
}
if (eeh_subsystem_enabled)
printk(KERN_INFO "EEH: PCI Enhanced I/O Error Handling Enabled\n");
else
printk(KERN_WARNING "EEH: No capable adapters found\n");
}
/**
* eeh_add_device_early - enable EEH for the indicated device_node
* @dn: device node for which to set up EEH
*
* This routine must be used to perform EEH initialization for PCI
* devices that were added after system boot (e.g. hotplug, dlpar).
* This routine must be called before any i/o is performed to the
* adapter (inluding any config-space i/o).
* Whether this actually enables EEH or not for this device depends
* on the CEC architecture, type of the device, on earlier boot
* command-line arguments & etc.
*/
static void eeh_add_device_early(struct device_node *dn)
{
struct pci_controller *phb;
struct eeh_early_enable_info info;
if (!dn || !PCI_DN(dn))
return;
phb = PCI_DN(dn)->phb;
/* USB Bus children of PCI devices will not have BUID's */
if (NULL == phb || 0 == phb->buid)
return;
info.buid_hi = BUID_HI(phb->buid);
info.buid_lo = BUID_LO(phb->buid);
early_enable_eeh(dn, &info);
}
void eeh_add_device_tree_early(struct device_node *dn)
{
struct device_node *sib;
for_each_child_of_node(dn, sib)
eeh_add_device_tree_early(sib);
eeh_add_device_early(dn);
}
EXPORT_SYMBOL_GPL(eeh_add_device_tree_early);
/**
* eeh_add_device_late - perform EEH initialization for the indicated pci device
* @dev: pci device for which to set up EEH
*
* This routine must be used to complete EEH initialization for PCI
* devices that were added after system boot (e.g. hotplug, dlpar).
*/
static void eeh_add_device_late(struct pci_dev *dev)
{
struct device_node *dn;
struct pci_dn *pdn;
if (!dev || !eeh_subsystem_enabled)
return;
#ifdef DEBUG
printk(KERN_DEBUG "EEH: adding device %s\n", pci_name(dev));
#endif
pci_dev_get (dev);
dn = pci_device_to_OF_node(dev);
pdn = PCI_DN(dn);
pdn->pcidev = dev;
pci_addr_cache_insert_device(dev);
eeh_sysfs_add_device(dev);
}
void eeh_add_device_tree_late(struct pci_bus *bus)
{
struct pci_dev *dev;
list_for_each_entry(dev, &bus->devices, bus_list) {
eeh_add_device_late(dev);
if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
struct pci_bus *subbus = dev->subordinate;
if (subbus)
eeh_add_device_tree_late(subbus);
}
}
}
EXPORT_SYMBOL_GPL(eeh_add_device_tree_late);
/**
* eeh_remove_device - undo EEH setup for the indicated pci device
* @dev: pci device to be removed
*
* This routine should be called when a device is removed from
* a running system (e.g. by hotplug or dlpar). It unregisters
* the PCI device from the EEH subsystem. I/O errors affecting
* this device will no longer be detected after this call; thus,
* i/o errors affecting this slot may leave this device unusable.
*/
static void eeh_remove_device(struct pci_dev *dev)
{
struct device_node *dn;
if (!dev || !eeh_subsystem_enabled)
return;
/* Unregister the device with the EEH/PCI address search system */
#ifdef DEBUG
printk(KERN_DEBUG "EEH: remove device %s\n", pci_name(dev));
#endif
pci_addr_cache_remove_device(dev);
eeh_sysfs_remove_device(dev);
dn = pci_device_to_OF_node(dev);
if (PCI_DN(dn)->pcidev) {
PCI_DN(dn)->pcidev = NULL;
pci_dev_put (dev);
}
}
void eeh_remove_bus_device(struct pci_dev *dev)
{
struct pci_bus *bus = dev->subordinate;
struct pci_dev *child, *tmp;
eeh_remove_device(dev);
if (bus && dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
list_for_each_entry_safe(child, tmp, &bus->devices, bus_list)
eeh_remove_bus_device(child);
}
}
EXPORT_SYMBOL_GPL(eeh_remove_bus_device);
static int proc_eeh_show(struct seq_file *m, void *v)
{
if (0 == eeh_subsystem_enabled) {
seq_printf(m, "EEH Subsystem is globally disabled\n");
seq_printf(m, "eeh_total_mmio_ffs=%ld\n", total_mmio_ffs);
} else {
seq_printf(m, "EEH Subsystem is enabled\n");
seq_printf(m,
"no device=%ld\n"
"no device node=%ld\n"
"no config address=%ld\n"
"check not wanted=%ld\n"
"eeh_total_mmio_ffs=%ld\n"
"eeh_false_positives=%ld\n"
"eeh_slot_resets=%ld\n",
no_device, no_dn, no_cfg_addr,
ignored_check, total_mmio_ffs,
false_positives,
slot_resets);
}
return 0;
}
static int proc_eeh_open(struct inode *inode, struct file *file)
{
return single_open(file, proc_eeh_show, NULL);
}
static const struct file_operations proc_eeh_operations = {
.open = proc_eeh_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static int __init eeh_init_proc(void)
{
if (machine_is(pseries))
proc_create("ppc64/eeh", 0, NULL, &proc_eeh_operations);
return 0;
}
__initcall(eeh_init_proc);
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