pci: Add helper to find a VPD resource data type

This patch adds the pci_vpd_find_tag() helper function to find VPD
resource data types in a buffer.
Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Signed-off-by: Michael Chan <mchan@broadcom.com>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bnx2.c

@@ -7769,28 +7769,12 @@ bnx2_read_vpd_fw_ver(struct bnx2 *bp)
 	}
 
 	for (i = 0; i <= BNX2_VPD_LEN - 3; ) {
-		unsigned char val = data[i];
 		unsigned int block_end;
 
-		if (val & PCI_VPD_LRDT) {
-			if (i + PCI_VPD_LRDT_TAG_SIZE > BNX2_VPD_LEN)
-				break;
-
-			if (val != PCI_VPD_LRDT_RO_DATA) {
-				i += PCI_VPD_LRDT_TAG_SIZE +
-				     pci_vpd_lrdt_size(&data[i]);
-
-				continue;
-			}
-		} else {
-			if ((val & PCI_VPD_SRDT_TIN_MASK) == PCI_VPD_STIN_END)
-				break;
-
-			i += PCI_VPD_SRDT_TAG_SIZE +
-			     pci_vpd_srdt_size(&data[i]);
-
-			continue;
-		}
+		i = pci_vpd_find_tag(data, i, BNX2_VPD_LEN,
+				     PCI_VPD_LRDT_RO_DATA);
+		if (i < 0)
+			break;
 
 		block_end = (i + PCI_VPD_LRDT_TAG_SIZE +
 			    pci_vpd_lrdt_size(&data[i]));

drivers/net/tg3.c

@@ -12547,7 +12547,7 @@ skip_phy_reset:
 static void __devinit tg3_read_partno(struct tg3 *tp)
 {
 	unsigned char vpd_data[TG3_NVM_VPD_LEN];   /* in little-endian format */
-	unsigned int i;
+	int i;
 	u32 magic;
 
 	if ((tp->tg3_flags3 & TG3_FLG3_NO_NVRAM) ||
@@ -12586,28 +12586,12 @@ static void __devinit tg3_read_partno(struct tg3 *tp)
 
 	/* Now parse and find the part number. */
 	for (i = 0; i < TG3_NVM_VPD_LEN - 2; ) {
-		unsigned char val = vpd_data[i];
 		unsigned int block_end;
 
-		if (val & PCI_VPD_LRDT) {
-			if (i + PCI_VPD_LRDT_TAG_SIZE > TG3_NVM_VPD_LEN)
-				break;
-
-			if (val != PCI_VPD_LRDT_RO_DATA) {
-				i += PCI_VPD_LRDT_TAG_SIZE +
-				     pci_vpd_lrdt_size(&vpd_data[i]);
-
-				continue;
-			}
-		} else {
-			if ((val & PCI_VPD_SRDT_TIN_MASK) == PCI_VPD_STIN_END)
-				break;
-
-			i += PCI_VPD_SRDT_TAG_SIZE +
-			     pci_vpd_srdt_size(&vpd_data[i]);
-
-			continue;
-		}
+		i = pci_vpd_find_tag(vpd_data, i, TG3_NVM_VPD_LEN,
+				     PCI_VPD_LRDT_RO_DATA);
+		if (i < 0)
+			break;
 
 		block_end = i + PCI_VPD_LRDT_TAG_SIZE +
 			    pci_vpd_lrdt_size(&vpd_data[i]);

drivers/pci/Makefile

@@ -4,7 +4,7 @@
 
 obj-y		+= access.o bus.o probe.o remove.o pci.o quirks.o \
 			pci-driver.o search.o pci-sysfs.o rom.o setup-res.o \
-			irq.o
+			irq.o vpd.o
 obj-$(CONFIG_PROC_FS) += proc.o
 obj-$(CONFIG_SYSFS) += slot.o
 

drivers/pci/vpd.c

+/*
+ * File:	vpd.c
+ * Purpose:	Provide PCI VPD support
+ *
+ * Copyright (C) 2010 Broadcom Corporation.
+ */
+
+#include <linux/pci.h>
+
+int pci_vpd_find_tag(const u8 *buf, unsigned int off, unsigned int len, u8 rdt)
+{
+	int i;
+
+	for (i = off; i < len; ) {
+		u8 val = buf[i];
+
+		if (val & PCI_VPD_LRDT) {
+			/* Don't return success of the tag isn't complete */
+			if (i + PCI_VPD_LRDT_TAG_SIZE > len)
+				break;
+
+			if (val == rdt)
+				return i;
+
+			i += PCI_VPD_LRDT_TAG_SIZE +
+			     pci_vpd_lrdt_size(&buf[i]);
+		} else {
+			u8 tag = val & ~PCI_VPD_SRDT_LEN_MASK;
+
+			if (tag == rdt)
+				return i;
+
+			if (tag == PCI_VPD_SRDT_END)
+				break;
+
+			i += PCI_VPD_SRDT_TAG_SIZE +
+			     pci_vpd_srdt_size(&buf[i]);
+		}
+	}
+
+	return -ENOENT;
+}
+EXPORT_SYMBOL_GPL(pci_vpd_find_tag);

include/linux/pci.h

@@ -1395,5 +1395,17 @@ static inline u8 pci_vpd_srdt_size(const u8 *srdt)
 	return (*srdt) & PCI_VPD_SRDT_LEN_MASK;
 }
 
+/**
+ * pci_vpd_find_tag - Locates the Resource Data Type tag provided
+ * @buf: Pointer to buffered vpd data
+ * @off: The offset into the buffer at which to begin the search
+ * @len: The length of the vpd buffer
+ * @rdt: The Resource Data Type to search for
+ *
+ * Returns the index where the Resource Data Type was found or
+ * -ENOENT otherwise.
+ */
+int pci_vpd_find_tag(const u8 *buf, unsigned int off, unsigned int len, u8 rdt);
+
 #endif /* __KERNEL__ */
 #endif /* LINUX_PCI_H */