[PATCH V4: 2/3] pci: Provide aer support when the error source id is bad

Zhang, Yanmin
2009-06-12T03:08:34Z

﻿﻿﻿When the bus id part of error source id is equal to 0 or nosourceid=1,
kernel probes the AER status registers of all devices under the root port
to find the initial error reporter.

﻿﻿﻿Signed-off-by: ﻿Zhang Yanmin <yanmin.zhang@linux.intel.com>

---

--- linux-2.6_next_pciwalk/drivers/pci/pcie/aer/aerdrv_core.c 2009-06-12 05:31:53.000000000 +0800
+++ linux-2.6_next_aernoid/drivers/pci/pcie/aer/aerdrv_core.c 2009-06-12 05:39:24.000000000 +0800
@@ -26,7 +26,9 @@
#include "aerdrv.h"

static int forceload;
+static int nosourceid;
module_param(forceload, bool, 0);
+module_param(nosourceid, bool, 0);

int pci_enable_pcie_error_reporting(struct pci_dev *dev)
{
@@ -143,34 +145,82 @@ static void set_downstream_devices_error
pci_walk_bus(dev->subordinate, set_device_error_reporting, &enable);
}

-static int find_device_iter(struct device *device, void *data)
+static int compare_device_id(struct pci_dev *dev, struct aer_err_info *e_info)
{
- struct pci_dev *dev;
- u16 id = *(unsigned long *)data;
- u8 secondary, subordinate, d_bus = id >> 8;
-
- if (device->bus == &pci_bus_type) {
- dev = to_pci_dev(device);
- if (id == ((dev->bus->number << 8) | dev->devfn)) {
- /*
- * Device ID match
- */
- *(unsigned long*)data = (unsigned long)device;
- return 1;
- }
-
+ if (e_info->id == ((dev->bus->number << 8) | dev->devfn)) {
/*
- * If device is P2P, check if it is an upstream?
+ * Device ID match
*/
- if (dev->hdr_type & PCI_HEADER_TYPE_BRIDGE) {
- pci_read_config_byte(dev, PCI_SECONDARY_BUS,
- &secondary);
- pci_read_config_byte(dev, PCI_SUBORDINATE_BUS,
- &subordinate);
- if (d_bus >= secondary && d_bus <= subordinate) {
- *(unsigned long*)data = (unsigned long)device;
- return 1;
- }
+ e_info->dev = dev;
+ return 1;
+ }
+
+ return 0;
+}
+
+#define PCI_BUS(x) (((x) >> 8) & 0xff)
+
+static int find_device_iter(struct pci_dev *dev, void *data)
+{
+ int pos;
+ u32 status;
+ u32 mask;
+ u16 reg16;
+ struct aer_err_info *e_info = (struct aer_err_info *)data;
+
+ /*
+ * When bus id is equal to 0, it might be a bad id
+ * reported by root port.
+ */
+ if (!nosourceid && (PCI_BUS(e_info->id) != 0))
+ return compare_device_id(dev, e_info);
+
+ /*
+ * Next is to check when bus id is equal to 0 or
+ * nosourceid==y. Some ports might lose the bus
+ * id of error source id. We check AER status
+ * registers to find the initial reporter.
+ */
+ if (atomic_read(&dev->enable_cnt) == 0)
+ return 0;
+ pos = pci_find_capability(dev, PCI_CAP_ID_EXP);
+ if (!pos)
+ return 0;
+ /* Check if AER is enabled */
+ pci_read_config_word(dev, pos+PCI_EXP_DEVCTL, &reg16);
+ if (!(reg16 & (
+ PCI_EXP_DEVCTL_CERE |
+ PCI_EXP_DEVCTL_NFERE |
+ PCI_EXP_DEVCTL_FERE |
+ PCI_EXP_DEVCTL_URRE)))
+ return 0;
+ pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
+ if (!pos)
+ return 0;
+
+ status = 0;
+ mask = 0;
+ if (e_info->severity == AER_CORRECTABLE) {
+ pci_read_config_dword(dev,
+ pos + PCI_ERR_COR_STATUS,
+ &status);
+ pci_read_config_dword(dev,
+ pos + PCI_ERR_COR_MASK,
+ &mask);
+ if (status & ERR_CORRECTABLE_ERROR_MASK & ~mask) {
+ e_info->dev = dev;
+ return 1;
+ }
+ } else {
+ pci_read_config_dword(dev,
+ pos + PCI_ERR_UNCOR_STATUS,
+ &status);
+ pci_read_config_dword(dev,
+ pos + PCI_ERR_UNCOR_MASK,
+ &mask);
+ if (status & ERR_UNCORRECTABLE_ERROR_MASK & ~mask) {
+ e_info->dev = dev;
+ return 1;
}
}

@@ -180,33 +230,23 @@ static int find_device_iter(struct devic
/**
* find_source_device - search through device hierarchy for source device
* @parent: pointer to Root Port pci_dev data structure
- * @id: device ID of agent who sends an error message to this Root Port
+ * @err_info: including detailed error information such like id
*
* Invoked when error is detected at the Root Port.
*/
-static struct device* find_source_device(struct pci_dev *parent, u16 id)
+static void find_source_device(struct pci_dev *parent,
+ struct aer_err_info *e_info)
{
struct pci_dev *dev = parent;
- struct device *device;
- unsigned long device_addr;
- int status;
+ int result;

/* Is Root Port an agent that sends error message? */
- if (id == ((dev->bus->number << 8) | dev->devfn))
- return &dev->dev;
-
- do {
- device_addr = id;
- if ((status = device_for_each_child(&dev->dev,
- &device_addr, find_device_iter))) {
- device = (struct device*)device_addr;
- dev = to_pci_dev(device);
- if (id == ((dev->bus->number << 8) | dev->devfn))
- return device;
- }
- }while (status);
+ result = find_device_iter(dev, e_info);
+ if (result)
+ return;

- return NULL;
+ pci_walk_bus(parent->subordinate, find_device_iter, e_info);
+ return;
}

static int report_error_detected(struct pci_dev *dev, void *data)
@@ -501,12 +541,12 @@ static pci_ers_result_t do_recovery(stru
*/
static void handle_error_source(struct pcie_device * aerdev,
struct pci_dev *dev,
- struct aer_err_info info)
+ struct aer_err_info *info)
{
pci_ers_result_t status = 0;
int pos;

- if (info.severity == AER_CORRECTABLE) {
+ if (info->severity == AER_CORRECTABLE) {
/*
* Correctable error does not need software intevention.
* No need to go through error recovery process.
@@ -514,9 +554,9 @@ static void handle_error_source(struct p
pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
if (pos)
pci_write_config_dword(dev, pos + PCI_ERR_COR_STATUS,
- info.status);
+ info->status);
} else {
- status = do_recovery(aerdev, dev, info.severity);
+ status = do_recovery(aerdev, dev, info->severity);
if (status == PCI_ERS_RESULT_RECOVERED) {
dev_printk(KERN_DEBUG, &dev->dev, "AER driver "
"successfully recovered\n");
@@ -673,10 +713,13 @@ static int get_device_error_info(struct
static void aer_isr_one_error(struct pcie_device *p_device,
struct aer_err_source *e_src)
{
- struct device *s_device;
- struct aer_err_info e_info = {0, 0, 0,};
+ struct aer_err_info *e_info;
int i;
- u16 id;
+
+ /* struct aer_err_info might be big, so we allocate it with slab */
+ e_info = kmalloc(sizeof(struct aer_err_info), GFP_KERNEL);
+ if (e_info == NULL)
+ return;

/*
* There is a possibility that both correctable error and
@@ -688,31 +731,37 @@ static void aer_isr_one_error(struct pci
if (!(e_src->status & i))
continue;

+ memset(e_info, 0, sizeof(struct aer_err_info));
+
/* Init comprehensive error information */
if (i & PCI_ERR_ROOT_COR_RCV) {
- id = ERR_COR_ID(e_src->id);
- e_info.severity = AER_CORRECTABLE;
+ e_info->id = ERR_COR_ID(e_src->id);
+ e_info->severity = AER_CORRECTABLE;
} else {
- id = ERR_UNCOR_ID(e_src->id);
- e_info.severity = ((e_src->status >> 6) & 1);
+ e_info->id = ERR_UNCOR_ID(e_src->id);
+ e_info->severity = ((e_src->status >> 6) & 1);
}
if (e_src->status &
(PCI_ERR_ROOT_MULTI_COR_RCV |
PCI_ERR_ROOT_MULTI_UNCOR_RCV))
- e_info.flags |= AER_MULTI_ERROR_VALID_FLAG;
- if (!(s_device = find_source_device(p_device->port, id))) {
+ e_info->flags |= AER_MULTI_ERROR_VALID_FLAG;
+
+ find_source_device(p_device->port, e_info);
+ if (e_info->dev == NULL) {
printk(KERN_DEBUG "%s->can't find device of ID%04x\n",
- __func__, id);
+ __func__, e_info->id);
continue;
}
- if (get_device_error_info(to_pci_dev(s_device), &e_info) ==
+ if (get_device_error_info(e_info->dev, e_info) ==
AER_SUCCESS) {
- aer_print_error(to_pci_dev(s_device), &e_info);
+ aer_print_error(e_info->dev, e_info);
handle_error_source(p_device,
- to_pci_dev(s_device),
+ e_info->dev,
e_info);
}
}
+
+ kfree(e_info);
}

/**
--- linux-2.6_next_pciwalk/drivers/pci/pcie/aer/aerdrv.h 2009-06-12 05:27:46.000000000 +0800
+++ linux-2.6_next_aernoid/drivers/pci/pcie/aer/aerdrv.h 2009-06-12 05:39:24.000000000 +0800
@@ -58,6 +58,8 @@ struct header_log_regs {
};

struct aer_err_info {
+ struct pci_dev *dev;
+ u16 id;
int severity; /* 0:NONFATAL | 1:FATAL | 2:COR */
int flags;
unsigned int status; /* COR/UNCOR Error Status */
--- linux-2.6_next_pciwalk/Documentation/PCI/pcieaer-howto.txt 2009-06-12 05:27:40.000000000 +0800
+++ linux-2.6_next_aernoid/Documentation/PCI/pcieaer-howto.txt 2009-06-12 05:39:24.000000000 +0800
@@ -60,6 +60,8 @@ forceload, a parameter of type bool, cou
be initiated although firmwares have no _OSC support. To enable the
walkaround, pls. add aerdriver.forceload=y to kernel boot parameter line
when booting kernel. Note that forceload=n by default.
+nosourceid, another parameter of type bool, is used when hardware (mostly
+chipset) has errata that root ports couldn't get error reporting source id.

2.3 AER error output
When a PCI-E AER error is captured, an error message will be outputed to