[pci] Add a mechanism for using a PCI VPD field as an NVS device

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/include/ipxe/nvsvpd.h

@@ -0,0 +1,33 @@
+#ifndef _IPXE_NVSVPD_H
+#define _IPXE_NVSVPD_H
+
+/**
+ * @file
+ *
+ * Non-Volatile Storage using Vital Product Data
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <ipxe/nvs.h>
+#include <ipxe/pcivpd.h>
+
+/** An NVS VPD device */
+struct nvs_vpd_device {
+	/** NVS device */
+	struct nvs_device nvs;
+	/** PCI VPD device */
+	struct pci_vpd vpd;
+	/** Starting address
+	 *
+	 * This address is added to the NVS address to form the VPD
+	 * address.
+	 */
+	unsigned int address;
+};
+
+extern int nvs_vpd_init ( struct nvs_vpd_device *nvsvpd, struct pci_device *pci,
+			  unsigned int field );
+
+#endif /* IPXE_NVSVPD_H */