PCI AER: support invalid error source IDs

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

Reviewed-by: Andrew Patterson <andrew.patterson@hp.com>
Signed-off-by: Zhang Yanmin <yanmin_zhang@linux.intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

diff --git a/Documentation/PCI/pcieaer-howto.txt b/Documentation/PCI/pcieaer-howto.txt
index f6b1ba7..5408b9b 100644 (file)
--- a/Documentation/PCI/pcieaer-howto.txt
+++ b/Documentation/PCI/pcieaer-howto.txt
@@ -61,6 +61,10 @@ 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, can be used when broken
+hardware (mostly chipsets) has root ports that cannot obtain the reporting
+source ID. nosourceid=n by default.
+
 2.3 AER error output
 When a PCI-E AER error is captured, an error message will be outputed to
 console. If it's a correctable error, it is outputed as a warning.

diff --git a/drivers/pci/pcie/aer/aerdrv.h b/drivers/pci/pcie/aer/aerdrv.h
index 3a69dde..dadf492 100644 (file)
--- a/drivers/pci/pcie/aer/aerdrv.h
+++ b/drivers/pci/pcie/aer/aerdrv.h
@@ -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 */

diff --git a/drivers/pci/pcie/aer/aerdrv_core.c b/drivers/pci/pcie/aer/aerdrv_core.c
index a7a3919..2750e7b 100644 (file)
--- a/drivers/pci/pcie/aer/aerdrv_core.c
+++ b/drivers/pci/pcie/aer/aerdrv_core.c
@@ -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 +145,87 @@ static void set_downstream_devices_error_reporting(struct pci_dev *dev,
        pci_walk_bus(dev->subordinate, set_device_error_reporting, &enable);
 }
 
-static int find_device_iter(struct device *device, void *data)
+static inline 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 (e_info->id == ((dev->bus->number << 8) | dev->devfn)) {
+               /*
+                * Device ID match
+                */
+               return 1;
+       }
 
-       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 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;
+       int result;
+       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)) {
+               result = compare_device_id(dev, e_info);
+               if (result)
+                       e_info->dev = dev;
+               return result;
+       }
+
+       /*
+        * 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;
                }
-
-               /*
-                * If device is P2P, check if it is an upstream?
-                */
-               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;
-                       }
+       } 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 +235,22 @@ static int find_device_iter(struct device *device, void *data)
 /**
  * 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);
 }
 
 static int report_error_detected(struct pci_dev *dev, void *data)
@@ -501,12 +545,12 @@ static pci_ers_result_t do_recovery(struct pcie_device *aerdev,
  */
 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 +558,9 @@ static void handle_error_source(struct pcie_device * aerdev,
                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 +717,16 @@ static int get_device_error_info(struct pci_dev *dev, struct aer_err_info *info)
 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) {
+               dev_printk(KERN_DEBUG, &p_device->port->dev,
+                       "Can't allocate mem when processing AER errors\n");
+               return;
+       }
 
        /*
         * There is a possibility that both correctable error and
@@ -688,31 +738,37 @@ static void aer_isr_one_error(struct pcie_device *p_device,
                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);
 }
 
 /**