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);