scsi: lpfc: Adding ability to reset chip via pci bus reset

This patch adds a "pci_bus_reset" option to the board_mode sysfs attribute.
This option uses the pci_reset_bus() api to reset the PCIe link the adapter
is on, which will reset the chip/adapter.  Prior to issuing this option,
all functions on the same chip must be placed in the offline state by the
admin. After the reset, all of the instances may be brought online again.

The primary purpose of this functionality is to support cases where
firmware update required a chip reset but the admin did not want to reboot
the machine in order to instantiate the firmware update.

Sanity checks take place prior to the reset to ensure the adapter is the
sole entity on the PCIe bus and that all functions are in the offline
state.

Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 82 insertions, 2 deletions

diff --git a/drivers/scsi/lpfc/lpfc_attr.c b/drivers/scsi/lpfc/lpfc_attr.c
index 513ac1be861f..4bae72cbf3f6 100644
--- a/drivers/scsi/lpfc/lpfc_attr.c
+++ b/drivers/scsi/lpfc/lpfc_attr.c
@@ -1192,6 +1192,82 @@ out:
 }
 
 /**
+ * lpfc_reset_pci_bus - resets PCI bridge controller's secondary bus of an HBA
+ * @phba: lpfc_hba pointer.
+ *
+ * Description:
+ * Issues a PCI secondary bus reset for the phba->pcidev.
+ *
+ * Notes:
+ * First walks the bus_list to ensure only PCI devices with Emulex
+ * vendor id, device ids that support hot reset, only one occurrence
+ * of function 0, and all ports on the bus are in offline mode to ensure the
+ * hot reset only affects one valid HBA.
+ *
+ * Returns:
+ * -ENOTSUPP, cfg_enable_hba_reset must be of value 2
+ * -ENODEV,   NULL ptr to pcidev
+ * -EBADSLT,  detected invalid device
+ * -EBUSY,    port is not in offline state
+ *      0,    successful
+ */
+int
+lpfc_reset_pci_bus(struct lpfc_hba *phba)
+{
+	struct pci_dev *pdev = phba->pcidev;
+	struct Scsi_Host *shost = NULL;
+	struct lpfc_hba *phba_other = NULL;
+	struct pci_dev *ptr = NULL;
+	int res;
+
+	if (phba->cfg_enable_hba_reset != 2)
+		return -ENOTSUPP;
+
+	if (!pdev) {
+		lpfc_printf_log(phba, KERN_INFO, LOG_INIT, "8345 pdev NULL!\n");
+		return -ENODEV;
+	}
+
+	res = lpfc_check_pci_resettable(phba);
+	if (res)
+		return res;
+
+	/* Walk the list of devices on the pci_dev's bus */
+	list_for_each_entry(ptr, &pdev->bus->devices, bus_list) {
+		/* Check port is offline */
+		shost = pci_get_drvdata(ptr);
+		if (shost) {
+			phba_other =
+				((struct lpfc_vport *)shost->hostdata)->phba;
+			if (!(phba_other->pport->fc_flag & FC_OFFLINE_MODE)) {
+				lpfc_printf_log(phba_other, KERN_INFO, LOG_INIT,
+						"8349 WWPN = 0x%02x%02x%02x%02x"
+						"%02x%02x%02x%02x is not "
+						"offline!\n",
+						phba_other->wwpn[0],
+						phba_other->wwpn[1],
+						phba_other->wwpn[2],
+						phba_other->wwpn[3],
+						phba_other->wwpn[4],
+						phba_other->wwpn[5],
+						phba_other->wwpn[6],
+						phba_other->wwpn[7]);
+				return -EBUSY;
+			}
+		}
+	}
+
+	/* Issue PCI bus reset */
+	res = pci_reset_bus(pdev);
+	if (res) {
+		lpfc_printf_log(phba, KERN_ERR, LOG_INIT,
+				"8350 PCI reset bus failed: %d\n", res);
+	}
+
+	return res;
+}
+
+/**
  * lpfc_selective_reset - Offline then onlines the port
  * @phba: lpfc_hba pointer.
  *
@@ -1618,6 +1694,9 @@ lpfc_board_mode_store(struct device *dev, struct device_attribute *attr,
 		status = lpfc_sli4_pdev_reg_request(phba, LPFC_FW_RESET);
 	else if (strncmp(buf, "dv_reset", sizeof("dv_reset") - 1) == 0)
 		status = lpfc_sli4_pdev_reg_request(phba, LPFC_DV_RESET);
+	else if (strncmp(buf, "pci_bus_reset", sizeof("pci_bus_reset") - 1)
+		 == 0)
+		status = lpfc_reset_pci_bus(phba);
 	else if (strncmp(buf, "trunk", sizeof("trunk") - 1) == 0)
 		status = lpfc_set_trunking(phba, (char *)buf + sizeof("trunk"));
 	else
@@ -5376,9 +5455,10 @@ LPFC_ATTR_R(nvme_io_channel,
 # lpfc_enable_hba_reset: Allow or prevent HBA resets to the hardware.
 #       0  = HBA resets disabled
 #       1  = HBA resets enabled (default)
-# Value range is [0,1]. Default value is 1.
+#       2  = HBA reset via PCI bus reset enabled
+# Value range is [0,2]. Default value is 1.
 */
-LPFC_ATTR_R(enable_hba_reset, 1, 0, 1, "Enable HBA resets from the driver.");
+LPFC_ATTR_RW(enable_hba_reset, 1, 0, 2, "Enable HBA resets from the driver.");
 
 /*
 # lpfc_enable_hba_heartbeat: Disable HBA heartbeat timer..