PCI: add interface to set visible size of VPD

The VPD on all devices may not be 32K. Unfortunately, there is no
generic way to find the size, so this adds a simple API hook
to reset it.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

drivers/pci/access.c

@@ -339,6 +339,29 @@ int pci_vpd_pci22_init(struct pci_dev *dev)
 	return 0;
 }
 
+/**
+ * pci_vpd_truncate - Set available Vital Product Data size
+ * @dev:	pci device struct
+ * @size:	available memory in bytes
+ *
+ * Adjust size of available VPD area.
+ */
+int pci_vpd_truncate(struct pci_dev *dev, size_t size)
+{
+	if (!dev->vpd)
+		return -EINVAL;
+
+	/* limited by the access method */
+	if (size > dev->vpd->len)
+		return -EINVAL;
+
+	dev->vpd->len = size;
+	dev->vpd->attr->size = size;
+
+	return 0;
+}
+EXPORT_SYMBOL(pci_vpd_truncate);
+
 /**
  * pci_block_user_cfg_access - Block userspace PCI config reads/writes
  * @dev:	pci device struct