[PATCH] PCI Error Recovery: header file patch

Various PCI bus errors can be signaled by newer PCI controllers.
Recovering from those errors requires an infrastructure to notify
affected device drivers of the error, and a way of walking through a
reset sequence.  This patch adds a set of callbacks to be used by error
recovery routines to notify device drivers of the various stages of
recovery.

Signed-off-by: Linas Vepstas <linas@austin.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 67 insertions, 0 deletions

diff --git a/include/linux/pci.h b/include/linux/pci.h
index d0e003926744..0a44072383ec 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -78,6 +78,23 @@ typedef int __bitwise pci_power_t;
 #define PCI_UNKNOWN     ((pci_power_t __force) 5)
 #define PCI_POWER_ERROR ((pci_power_t __force) -1)
 
+/** The pci_channel state describes connectivity between the CPU and
+ *  the pci device.  If some PCI bus between here and the pci device
+ *  has crashed or locked up, this info is reflected here.
+ */
+typedef unsigned int __bitwise pci_channel_state_t;
+
+enum pci_channel_state {
+        /* I/O channel is in normal state */
+        pci_channel_io_normal = (__force pci_channel_state_t) 1,
+
+        /* I/O to channel is blocked */
+        pci_channel_io_frozen = (__force pci_channel_state_t) 2,
+
+        /* PCI card is dead */
+        pci_channel_io_perm_failure = (__force pci_channel_state_t) 3,
+};
+
 /*
  * The pci_dev structure is used to describe PCI devices.
  */
@@ -111,6 +128,7 @@ struct pci_dev {
                                            this is D0-D3, D0 being fully functional,
                                            and D3 being off. */
 
+        pci_channel_state_t error_state;        /* current connectivity state */
         struct  device  dev;            /* Generic device interface */
 
         /* device is compatible with these IDs */
@@ -233,6 +251,54 @@ struct pci_dynids {
         unsigned int use_driver_data:1; /* pci_driver->driver_data is used */
 };
 
+/* ---------------------------------------------------------------- */
+/** PCI Error Recovery System (PCI-ERS).  If a PCI device driver provides
+ *  a set fof callbacks in struct pci_error_handlers, then that device driver
+ *  will be notified of PCI bus errors, and will be driven to recovery
+ *  when an error occurs.
+ */
+
+typedef unsigned int __bitwise pci_ers_result_t;
+
+enum pci_ers_result {
+        /* no result/none/not supported in device driver */
+        PCI_ERS_RESULT_NONE = (__force pci_ers_result_t) 1,
+
+        /* Device driver can recover without slot reset */
+        PCI_ERS_RESULT_CAN_RECOVER = (__force pci_ers_result_t) 2,
+
+        /* Device driver wants slot to be reset. */
+        PCI_ERS_RESULT_NEED_RESET = (__force pci_ers_result_t) 3,
+
+        /* Device has completely failed, is unrecoverable */
+        PCI_ERS_RESULT_DISCONNECT = (__force pci_ers_result_t) 4,
+
+        /* Device driver is fully recovered and operational */
+        PCI_ERS_RESULT_RECOVERED = (__force pci_ers_result_t) 5,
+};
+
+/* PCI bus error event callbacks */
+struct pci_error_handlers
+{
+        /* PCI bus error detected on this device */
+        pci_ers_result_t (*error_detected)(struct pci_dev *dev,
+                              enum pci_channel_state error);
+
+        /* MMIO has been re-enabled, but not DMA */
+        pci_ers_result_t (*mmio_enabled)(struct pci_dev *dev);
+
+        /* PCI Express link has been reset */
+        pci_ers_result_t (*link_reset)(struct pci_dev *dev);
+
+        /* PCI slot has been reset */
+        pci_ers_result_t (*slot_reset)(struct pci_dev *dev);
+
+        /* Device driver may resume normal operations */
+        void (*resume)(struct pci_dev *dev);
+};
+
+/* ---------------------------------------------------------------- */
+
 struct module;
 struct pci_driver {
         struct list_head node;
@@ -245,6 +311,7 @@ struct pci_driver {
         int  (*enable_wake) (struct pci_dev *dev, pci_power_t state, int enable);   /* Enable wake event */
         void (*shutdown) (struct pci_dev *dev);
 
+        struct pci_error_handlers *err_handler;
         struct device_driver    driver;
         struct pci_dynids dynids;
 };