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, 101 insertions, 20 deletions

diff --git a/drivers/scsi/lpfc/lpfc_scsi.c b/drivers/scsi/lpfc/lpfc_scsi.c
index 473d255f15c0..f61de71ff713 100644
--- a/drivers/scsi/lpfc/lpfc_scsi.c
+++ b/drivers/scsi/lpfc/lpfc_scsi.c
@@ -4460,6 +4460,66 @@ lpfc_tskmgmt_def_cmpl(struct lpfc_hba *phba,
 }
 
 /**
+ * lpfc_check_pci_resettable - Walks list of devices on pci_dev's bus to check
+ *                             if issuing a pci_bus_reset is possibly unsafe
+ * @phba: lpfc_hba pointer.
+ *
+ * Description:
+ * Walks the bus_list to ensure only PCI devices with Emulex
+ * vendor id, device ids that support hot reset, and only one occurrence
+ * of function 0.
+ *
+ * Returns:
+ * -EBADSLT,  detected invalid device
+ *      0,    successful
+ */
+int
+lpfc_check_pci_resettable(const struct lpfc_hba *phba)
+{
+	const struct pci_dev *pdev = phba->pcidev;
+	struct pci_dev *ptr = NULL;
+	u8 counter = 0;
+
+	/* Walk the list of devices on the pci_dev's bus */
+	list_for_each_entry(ptr, &pdev->bus->devices, bus_list) {
+		/* Check for Emulex Vendor ID */
+		if (ptr->vendor != PCI_VENDOR_ID_EMULEX) {
+			lpfc_printf_log(phba, KERN_INFO, LOG_INIT,
+					"8346 Non-Emulex vendor found: "
+					"0x%04x\n", ptr->vendor);
+			return -EBADSLT;
+		}
+
+		/* Check for valid Emulex Device ID */
+		switch (ptr->device) {
+		case PCI_DEVICE_ID_LANCER_FC:
+		case PCI_DEVICE_ID_LANCER_G6_FC:
+		case PCI_DEVICE_ID_LANCER_G7_FC:
+			break;
+		default:
+			lpfc_printf_log(phba, KERN_INFO, LOG_INIT,
+					"8347 Invalid device found: "
+					"0x%04x\n", ptr->device);
+			return -EBADSLT;
+		}
+
+		/* Check for only one function 0 ID to ensure only one HBA on
+		 * secondary bus
+		 */
+		if (ptr->devfn == 0) {
+			if (++counter > 1) {
+				lpfc_printf_log(phba, KERN_INFO, LOG_INIT,
+						"8348 More than one device on "
+						"secondary bus found\n");
+				return -EBADSLT;
+			}
+		}
+	}
+
+	return 0;
+}
+
+/**
  * lpfc_info - Info entry point of scsi_host_template data structure
  * @host: The scsi host for which this call is being executed.
  *
@@ -4473,32 +4533,53 @@ lpfc_info(struct Scsi_Host *host)
 {
 	struct lpfc_vport *vport = (struct lpfc_vport *) host->hostdata;
 	struct lpfc_hba   *phba = vport->phba;
-	int len, link_speed = 0;
-	static char  lpfcinfobuf[384];
+	int link_speed = 0;
+	static char lpfcinfobuf[384];
+	char tmp[384] = {0};
 
-	memset(lpfcinfobuf,0,384);
+	memset(lpfcinfobuf, 0, sizeof(lpfcinfobuf));
 	if (phba && phba->pcidev){
-		strncpy(lpfcinfobuf, phba->ModelDesc, 256);
-		len = strlen(lpfcinfobuf);
-		snprintf(lpfcinfobuf + len,
-			384-len,
-			" on PCI bus %02x device %02x irq %d",
-			phba->pcidev->bus->number,
-			phba->pcidev->devfn,
-			phba->pcidev->irq);
-		len = strlen(lpfcinfobuf);
+		/* Model Description */
+		scnprintf(tmp, sizeof(tmp), phba->ModelDesc);
+		if (strlcat(lpfcinfobuf, tmp, sizeof(lpfcinfobuf)) >=
+		    sizeof(lpfcinfobuf))
+			goto buffer_done;
+
+		/* PCI Info */
+		scnprintf(tmp, sizeof(tmp),
+			  " on PCI bus %02x device %02x irq %d",
+			  phba->pcidev->bus->number, phba->pcidev->devfn,
+			  phba->pcidev->irq);
+		if (strlcat(lpfcinfobuf, tmp, sizeof(lpfcinfobuf)) >=
+		    sizeof(lpfcinfobuf))
+			goto buffer_done;
+
+		/* Port Number */
 		if (phba->Port[0]) {
-			snprintf(lpfcinfobuf + len,
-				 384-len,
-				 " port %s",
-				 phba->Port);
+			scnprintf(tmp, sizeof(tmp), " port %s", phba->Port);
+			if (strlcat(lpfcinfobuf, tmp, sizeof(lpfcinfobuf)) >=
+			    sizeof(lpfcinfobuf))
+				goto buffer_done;
 		}
-		len = strlen(lpfcinfobuf);
+
+		/* Link Speed */
 		link_speed = lpfc_sli_port_speed_get(phba);
-		if (link_speed != 0)
-			snprintf(lpfcinfobuf + len, 384-len,
-				 " Logical Link Speed: %d Mbps", link_speed);
+		if (link_speed != 0) {
+			scnprintf(tmp, sizeof(tmp),
+				  " Logical Link Speed: %d Mbps", link_speed);
+			if (strlcat(lpfcinfobuf, tmp, sizeof(lpfcinfobuf)) >=
+			    sizeof(lpfcinfobuf))
+				goto buffer_done;
+		}
+
+		/* PCI resettable */
+		if (!lpfc_check_pci_resettable(phba)) {
+			scnprintf(tmp, sizeof(tmp), " PCI resettable");
+			strlcat(lpfcinfobuf, tmp, sizeof(lpfcinfobuf));
+		}
 	}
+
+buffer_done:
 	return lpfcinfobuf;
 }