drivers/vpd: Add VPD support

VPD reference: https://chromium.googlesource.com/chromiumos/platform/vpd/+/master/README.md

Copy ChromeOS VPD driver to add support for VPD without CROMEOS.
Possible use case:
* Storing calibration data
* Storing MAC address
* Storing serial
* Storing boot options

+ Now it's possible to define the VPD space by choosing
  one of the following enums: VPD_ANY, VPD_RW, VPD_RO.
+ CHROMEOS selects now VPD as part of it.
+ VPD is implemented as driver.

Change-Id: Id9263bd39bf25d024e93daa57053fefcb1adc53a
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/25046
Reviewed-by: David Hendricks <david.hendricks@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

1 files changed, 42 insertions, 0 deletions

diff --git a/src/drivers/vpd/vpd.h b/src/drivers/vpd/vpd.h
new file mode 100644
index 0000000000..6009b8bc0d
--- /dev/null
+++ b/src/drivers/vpd/vpd.h
@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef __VPD_H__
+#define __VPD_H__
+
+enum vpd_region {
+	VPD_ANY = 0,
+	VPD_RO = 1,
+	VPD_RW = 2
+};
+/*
+ * Reads VPD string value by key.
+ *
+ * Reads in at most one less than size characters from VPD and stores them
+ * into buffer. A terminating null byte ('\0') is stored after the last
+ * character in the buffer.
+ *
+ * Returns NULL if key is not found, otherwise buffer.
+ */
+char *vpd_gets(const char *key, char *buffer, int size, enum vpd_region region);
+
+/*
+ * Find VPD value by key.
+ *
+ * Searches for a VPD entry in the VPD cache. If found, places the size of the
+ * entry into '*size' and returns the pointer to the entry data.
+ *
+ * This function presumes that VPD is cached in DRAM (which is the case in the
+ * current implementation) and as such returns the pointer into the cache. The
+ * user is not supposed to modify the data, and does not have to free the
+ * memory.
+ *
+ * Returns NULL if key is not found.
+ */
+
+const void *vpd_find(const char *key, int *size, enum vpd_region region);
+
+#endif  /* __VPD_H__ */