From: Guixin Liu <kanie@linux.alibaba.com>
Date: Fri, 8 May 2026 08:21:27 +0000 (+0800)
Subject: PCI: Introduce named defines for PCI ROM
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=113e86bc58a918f85d250723436a4d541a873358;p=thirdparty%2Flinux.git

PCI: Introduce named defines for PCI ROM

Convert the magic numbers associated with PCI ROM into named
definitions. Some of these definitions will be used in the second
fix patch.

Signed-off-by: Guixin Liu <kanie@linux.alibaba.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Reviewed-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Link: https://patch.msgid.link/20260508082128.3344255-2-kanie@linux.alibaba.com
---

diff --git a/drivers/pci/rom.c b/drivers/pci/rom.c
index e18d3a4383ba6..d4a141bd148b4 100644
--- a/drivers/pci/rom.c
+++ b/drivers/pci/rom.c
@@ -5,13 +5,28 @@
  * (C) Copyright 2004 Jon Smirl <jonsmirl@yahoo.com>
  * (C) Copyright 2004 Silicon Graphics, Inc. Jesse Barnes <jbarnes@sgi.com>
  */
+
+#include <linux/bits.h>
 #include <linux/kernel.h>
 #include <linux/export.h>
 #include <linux/pci.h>
+#include <linux/sizes.h>
 #include <linux/slab.h>
 
 #include "pci.h"
 
+#define PCI_ROM_HEADER_SIZE			0x1A
+#define PCI_ROM_POINTER_TO_DATA_STRUCT		0x18
+#define PCI_ROM_LAST_IMAGE_INDICATOR		0x15
+#define PCI_ROM_LAST_IMAGE_INDICATOR_BIT	BIT(7)
+#define PCI_ROM_IMAGE_LEN			0x10
+#define PCI_ROM_IMAGE_SECTOR_SIZE		SZ_512
+#define PCI_ROM_IMAGE_SIGNATURE			0xAA55
+
+/* Data structure signature is "PCIR" in ASCII representation */
+#define PCI_ROM_DATA_STRUCT_SIGNATURE		0x52494350
+#define PCI_ROM_DATA_STRUCT_LEN			0x0A
+
 /**
  * pci_enable_rom - enable ROM decoding for a PCI device
  * @pdev: PCI device to enable
@@ -91,26 +106,27 @@ static size_t pci_get_rom_size(struct pci_dev *pdev, void __iomem *rom,
 	do {
 		void __iomem *pds;
 		/* Standard PCI ROMs start out with these bytes 55 AA */
-		if (readw(image) != 0xAA55) {
-			pci_info(pdev, "Invalid PCI ROM header signature: expecting 0xaa55, got %#06x\n",
-				 readw(image));
+		if (readw(image) != PCI_ROM_IMAGE_SIGNATURE) {
+			pci_info(pdev, "Invalid PCI ROM header signature: expecting %#06x, got %#06x\n",
+				 PCI_ROM_IMAGE_SIGNATURE, readw(image));
 			break;
 		}
-		/* get the PCI data structure and check its "PCIR" signature */
-		pds = image + readw(image + 24);
-		if (readl(pds) != 0x52494350) {
-			pci_info(pdev, "Invalid PCI ROM data signature: expecting 0x52494350, got %#010x\n",
-				 readl(pds));
+		/* Get the PCI data structure and check its "PCIR" signature */
+		pds = image + readw(image + PCI_ROM_POINTER_TO_DATA_STRUCT);
+		if (readl(pds) != PCI_ROM_DATA_STRUCT_SIGNATURE) {
+			pci_info(pdev, "Invalid PCI ROM data signature: expecting %#010x, got %#010x\n",
+				 PCI_ROM_DATA_STRUCT_SIGNATURE, readl(pds));
 			break;
 		}
-		last_image = readb(pds + 21) & 0x80;
-		length = readw(pds + 16);
-		image += length * 512;
+		last_image = readb(pds + PCI_ROM_LAST_IMAGE_INDICATOR) &
+				   PCI_ROM_LAST_IMAGE_INDICATOR_BIT;
+		length = readw(pds + PCI_ROM_IMAGE_LEN);
+		image += length * PCI_ROM_IMAGE_SECTOR_SIZE;
 		/* Avoid iterating through memory outside the resource window */
 		if (image >= rom + size)
 			break;
 		if (!last_image) {
-			if (readw(image) != 0xAA55) {
+			if (readw(image) != PCI_ROM_IMAGE_SIGNATURE) {
 				pci_info(pdev, "No more image in the PCI ROM\n");
 				break;
 			}