[SCSI] PCI Error Recovery: IPR SCSI device driver

Various PCI bus errors can be signaled by newer PCI controllers.  This
patch adds the PCI error recovery callbacks to the IPR SCSI device driver.
The patch has been tested, and appears to work well.
Signed-off-by: NLinas Vepstas <linas@linas.org>
Signed-off-by: NBrian King <brking@us.ibm.com>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

drivers/scsi/ipr.c

@@ -5830,6 +5830,109 @@ static void ipr_initiate_ioa_reset(struct ipr_ioa_cfg *ioa_cfg,
 				shutdown_type);
 }
 
+/**
+ * ipr_reset_freeze - Hold off all I/O activity
+ * @ipr_cmd:	ipr command struct
+ *
+ * Description: If the PCI slot is frozen, hold off all I/O
+ * activity; then, as soon as the slot is available again,
+ * initiate an adapter reset.
+ */
+static int ipr_reset_freeze(struct ipr_cmnd *ipr_cmd)
+{
+	/* Disallow new interrupts, avoid loop */
+	ipr_cmd->ioa_cfg->allow_interrupts = 0;
+	list_add_tail(&ipr_cmd->queue, &ipr_cmd->ioa_cfg->pending_q);
+	ipr_cmd->done = ipr_reset_ioa_job;
+	return IPR_RC_JOB_RETURN;
+}
+
+/**
+ * ipr_pci_frozen - Called when slot has experienced a PCI bus error.
+ * @pdev:	PCI device struct
+ *
+ * Description: This routine is called to tell us that the PCI bus
+ * is down. Can't do anything here, except put the device driver
+ * into a holding pattern, waiting for the PCI bus to come back.
+ */
+static void ipr_pci_frozen(struct pci_dev *pdev)
+{
+	unsigned long flags = 0;
+	struct ipr_ioa_cfg *ioa_cfg = pci_get_drvdata(pdev);
+
+	spin_lock_irqsave(ioa_cfg->host->host_lock, flags);
+	_ipr_initiate_ioa_reset(ioa_cfg, ipr_reset_freeze, IPR_SHUTDOWN_NONE);
+	spin_unlock_irqrestore(ioa_cfg->host->host_lock, flags);
+}
+
+/**
+ * ipr_pci_slot_reset - Called when PCI slot has been reset.
+ * @pdev:	PCI device struct
+ *
+ * Description: This routine is called by the pci error recovery
+ * code after the PCI slot has been reset, just before we
+ * should resume normal operations.
+ */
+static pci_ers_result_t ipr_pci_slot_reset(struct pci_dev *pdev)
+{
+	unsigned long flags = 0;
+	struct ipr_ioa_cfg *ioa_cfg = pci_get_drvdata(pdev);
+
+	spin_lock_irqsave(ioa_cfg->host->host_lock, flags);
+	_ipr_initiate_ioa_reset(ioa_cfg, ipr_reset_restore_cfg_space,
+	                                 IPR_SHUTDOWN_NONE);
+	spin_unlock_irqrestore(ioa_cfg->host->host_lock, flags);
+	return PCI_ERS_RESULT_RECOVERED;
+}
+
+/**
+ * ipr_pci_perm_failure - Called when PCI slot is dead for good.
+ * @pdev:	PCI device struct
+ *
+ * Description: This routine is called when the PCI bus has
+ * permanently failed.
+ */
+static void ipr_pci_perm_failure(struct pci_dev *pdev)
+{
+	unsigned long flags = 0;
+	struct ipr_ioa_cfg *ioa_cfg = pci_get_drvdata(pdev);
+
+	spin_lock_irqsave(ioa_cfg->host->host_lock, flags);
+	if (ioa_cfg->sdt_state == WAIT_FOR_DUMP)
+		ioa_cfg->sdt_state = ABORT_DUMP;
+	ioa_cfg->reset_retries = IPR_NUM_RESET_RELOAD_RETRIES;
+	ioa_cfg->in_ioa_bringdown = 1;
+	ipr_initiate_ioa_reset(ioa_cfg, IPR_SHUTDOWN_NONE);
+	spin_unlock_irqrestore(ioa_cfg->host->host_lock, flags);
+}
+
+/**
+ * ipr_pci_error_detected - Called when a PCI error is detected.
+ * @pdev:	PCI device struct
+ * @state:	PCI channel state
+ *
+ * Description: Called when a PCI error is detected.
+ *
+ * Return value:
+ * 	PCI_ERS_RESULT_NEED_RESET or PCI_ERS_RESULT_DISCONNECT
+ */
+static pci_ers_result_t ipr_pci_error_detected(struct pci_dev *pdev,
+					       pci_channel_state_t state)
+{
+	switch (state) {
+	case pci_channel_io_frozen:
+		ipr_pci_frozen(pdev);
+		return PCI_ERS_RESULT_NEED_RESET;
+	case pci_channel_io_perm_failure:
+		ipr_pci_perm_failure(pdev);
+		return PCI_ERS_RESULT_DISCONNECT;
+		break;
+	default:
+		break;
+	}
+	return PCI_ERS_RESULT_NEED_RESET;
+}
+
 /**
  * ipr_probe_ioa_part2 - Initializes IOAs found in ipr_probe_ioa(..)
  * @ioa_cfg:	ioa cfg struct
@@ -6601,12 +6704,18 @@ static struct pci_device_id ipr_pci_table[] __devinitdata = {
 };
 MODULE_DEVICE_TABLE(pci, ipr_pci_table);
 
+static struct pci_error_handlers ipr_err_handler = {
+	.error_detected = ipr_pci_error_detected,
+	.slot_reset = ipr_pci_slot_reset,
+};
+
 static struct pci_driver ipr_driver = {
 	.name = IPR_NAME,
 	.id_table = ipr_pci_table,
 	.probe = ipr_probe,
 	.remove = ipr_remove,
 	.shutdown = ipr_shutdown,
+	.err_handler = &ipr_err_handler,
 };
 
 /**