PCI/DPC: Use defines with DPC reason fields

Add new defines for DPC reason fields and use them instead of literals.

Link: https://lore.kernel.org/r/20231018113254.17616-7-ilpo.jarvinen@linux.intel.com
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
[bhelgaas: shorten comments]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

Author: ij-intel

drivers/pci/pcie/dpc.c

@@ -274,20 +274,27 @@ void dpc_process_error(struct pci_dev *pdev)
 	pci_info(pdev, "containment event, status:%#06x source:%#06x\n",
 		 status, source);
 
-	reason = (status & PCI_EXP_DPC_STATUS_TRIGGER_RSN) >> 1;
-	ext_reason = (status & PCI_EXP_DPC_STATUS_TRIGGER_RSN_EXT) >> 5;
+	reason = status & PCI_EXP_DPC_STATUS_TRIGGER_RSN;
+	ext_reason = status & PCI_EXP_DPC_STATUS_TRIGGER_RSN_EXT;
 	pci_warn(pdev, "%s detected\n",
-		 (reason == 0) ? "unmasked uncorrectable error" :
-		 (reason == 1) ? "ERR_NONFATAL" :
-		 (reason == 2) ? "ERR_FATAL" :
-		 (ext_reason == 0) ? "RP PIO error" :
-		 (ext_reason == 1) ? "software trigger" :
-				     "reserved error");
+		 (reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_UNCOR) ?
+		 "unmasked uncorrectable error" :
+		 (reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_NFE) ?
+		 "ERR_NONFATAL" :
+		 (reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_FE) ?
+		 "ERR_FATAL" :
+		 (ext_reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_RP_PIO) ?
+		 "RP PIO error" :
+		 (ext_reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_SW_TRIGGER) ?
+		 "software trigger" :
+		 "reserved error");
 
 	/* show RP PIO error detail information */
-	if (pdev->dpc_rp_extensions && reason == 3 && ext_reason == 0)
+	if (pdev->dpc_rp_extensions &&
+	    reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_IN_EXT &&
+	    ext_reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_RP_PIO)
 		dpc_process_rp_pio_error(pdev);
-	else if (reason == 0 &&
+	else if (reason == PCI_EXP_DPC_STATUS_TRIGGER_RSN_UNCOR &&
 		 dpc_get_aer_uncorrect_severity(pdev, &info) &&
 		 aer_get_device_error_info(pdev, &info)) {
 		aer_print_error(pdev, &info);

include/uapi/linux/pci_regs.h

@@ -1044,9 +1044,15 @@
 #define PCI_EXP_DPC_STATUS		0x08	/* DPC Status */
 #define  PCI_EXP_DPC_STATUS_TRIGGER	    0x0001 /* Trigger Status */
 #define  PCI_EXP_DPC_STATUS_TRIGGER_RSN	    0x0006 /* Trigger Reason */
+#define  PCI_EXP_DPC_STATUS_TRIGGER_RSN_UNCOR  0x0000 /* Uncorrectable error */
+#define  PCI_EXP_DPC_STATUS_TRIGGER_RSN_NFE    0x0002 /* Rcvd ERR_NONFATAL */
+#define  PCI_EXP_DPC_STATUS_TRIGGER_RSN_FE     0x0004 /* Rcvd ERR_FATAL */
+#define  PCI_EXP_DPC_STATUS_TRIGGER_RSN_IN_EXT 0x0006 /* Reason in Trig Reason Extension field */
 #define  PCI_EXP_DPC_STATUS_INTERRUPT	    0x0008 /* Interrupt Status */
 #define  PCI_EXP_DPC_RP_BUSY		    0x0010 /* Root Port Busy */
 #define  PCI_EXP_DPC_STATUS_TRIGGER_RSN_EXT 0x0060 /* Trig Reason Extension */
+#define  PCI_EXP_DPC_STATUS_TRIGGER_RSN_RP_PIO		0x0000	/* RP PIO error */
+#define  PCI_EXP_DPC_STATUS_TRIGGER_RSN_SW_TRIGGER	0x0020	/* DPC SW Trigger bit */
 #define  PCI_EXP_DPC_RP_PIO_FEP		    0x1f00 /* RP PIO First Err Ptr */
 
 #define PCI_EXP_DPC_SOURCE_ID		 0x0A	/* DPC Source Identifier */