vendorcode: Add ChromeOS VPD parser.

Copied (and unmodified) the minimal bits from ChromeOS libVPD:
 https://chromium.googlesource.com/chromiumos/platform/vpd

BUG=none
TEST=emerge-panther chromeos-coreboot-panther

Change-Id: Id75d1bfd16263ac1b94c22979f9892cf7908d5e6
Signed-off-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/187411
Reviewed-by: Yung-chieh Lo <yjlou@chromium.org>

src/vendorcode/google/chromeos/Makefile.inc

@@ -28,6 +28,8 @@ ramstage-y += gnvs.c
 romstage-y += fmap.c
 ramstage-y += fmap.c
 smm-y += fmap.c
+romstage-y += vpd_decode.c
+ramstage-y += vpd_decode.c
 ifneq ($(wildcard src/mainboard/$(MAINBOARDDIR)/chromeos.c),)
 ramstage-srcs += src/mainboard/$(MAINBOARDDIR)/chromeos.c
 romstage-srcs += src/mainboard/$(MAINBOARDDIR)/chromeos.c

src/vendorcode/google/chromeos/lib_vpd.h

@@ -0,0 +1,225 @@
+/*
+ * Copyright (c) 2013 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 __LIB_VPD__
+#define __LIB_VPD__
+
+#include <inttypes.h>
+
+enum {
+  VPD_OK = 0,
+  VPD_FAIL,
+};
+
+enum {
+  VPD_TYPE_TERMINATOR = 0,
+  VPD_TYPE_STRING,
+  VPD_TYPE_IMPLICIT_TERMINATOR = 0xff,
+};
+
+enum {
+  VPD_AS_LONG_AS = -1,
+};
+
+enum {  /* export_type */
+  VPD_EXPORT_KEY_VALUE = 1,
+  VPD_EXPORT_VALUE,
+  VPD_EXPORT_AS_PARAMETER,
+};
+
+/* Callback for decodeVpdString to invoke. */
+typedef int VpdDecodeCallback(const uint8_t *key, int32_t key_len,
+                              const uint8_t *value, int32_t value_len,
+                              void *arg);
+
+/* Container data types */
+struct StringPair {
+  uint8_t *key;
+  uint8_t *value;
+  int pad_len;
+  int filter_out;  /* TRUE means not exported. */
+  struct StringPair *next;
+};
+
+struct PairContainer {
+  struct StringPair *first;
+};
+
+
+/***********************************************************************
+ * Encode and decode VPD entries
+ ***********************************************************************/
+
+/* Encodes the len into multiple bytes with the following format.
+ *
+ *    7   6 ............ 0
+ *  +----+------------------+
+ *  |More|      Length      |  ...
+ *  +----+------------------+
+ *
+ * The encode_buf points to the actual position we are going to store.
+ * encoded_len will return the exact bytes we encoded in this function.
+ * Returns fail if the buffer is not long enough.
+ */
+int encodeLen(
+    const int32_t len,
+    uint8_t *encode_buf,
+    const int32_t max_len,
+    int32_t *encoded_len);
+
+/* Given an encoded string, this functions decodes the length field which varies
+ * from 1 byte to many bytes.
+ *
+ * The in points the actual byte going to be decoded. The *length returns
+ * the decoded length field. The number of consumed bytes will be stroed in
+ * decoded_len.
+ *
+ * Returns VPD_FAIL if more bit is 1, but actually reaches the end of string.
+ */
+int decodeLen(
+    const int32_t max_len,
+    const uint8_t *in,
+    int32_t *length,
+    int32_t *decoded_len);
+
+
+/* Encodes the terminator.
+ * When calling, the output_buf should point to the start of buffer while
+ * *generated_len should contain how many bytes exist in buffer now.
+ * After return, *generated_len would be plused the number of bytes generated
+ * in this function.
+ */
+int encodeVpdTerminator(
+    const int max_buffer_len,
+    uint8_t *output_buf,
+    int *generated_len);
+
+/* Encodes the given type/key/value pair into buffer.
+ *
+ * The pad_value_len is used to control the output value length.
+ * When pad_value_len > 0, the value is outputted into fixed length (pad \0
+ *                         if the value is shorter). Truncated if too long.
+ *      pad_value_len == VPD_NO_LIMIT, output the value as long as possible.
+ * This is useful when we want to fix the structure layout at beginning.
+ *
+ * The encoded string will be stored in output_buf. If it is longer than
+ * max_buffer_len, this function returns fail. If the buffer is long enough,
+ * the generated_len will be updated.
+ *
+ * When calling, the output_buf should point to the start of buffer while
+ * *generated_len should contain how many bytes exist in buffer now.
+ * After return, *generated_len would be plused the number of bytes generated
+ * in this function.
+ *
+ * The initial value of *generated_len can be non-zero, so that this value
+ * can be used between multiple calls to encodeVpd2Pair().
+ */
+int encodeVpdString(
+    const uint8_t *key,
+    const uint8_t *value,
+    const int pad_value_len,
+    const int max_buffer_len,
+    uint8_t *output_buf,
+    int *generated_len);
+
+
+/* Given the encoded string, this function invokes callback with extracted
+ * (key, value). The *consumed will be plused the number of bytes consumed in
+ * this function.
+ *
+ * The input_buf points to the first byte of the input buffer.
+ *
+ * The *consumed starts from 0, which is actually the next byte to be decoded.
+ * It can be non-zero to be used in multiple calls.
+ *
+ * If one entry is successfully decoded, sends it to callback and returns the
+ * result.
+ */
+int decodeVpdString(
+    const int32_t max_len,
+    const uint8_t *input_buf,
+    int32_t *consumed,
+    VpdDecodeCallback callback,
+    void *callback_arg);
+
+/***********************************************************************
+ * Container helpers
+ ***********************************************************************/
+void initContainer(struct PairContainer *container);
+
+struct StringPair *findString(struct PairContainer *container,
+                              const uint8_t *key,
+                              struct StringPair ***prev_next);
+
+/* If key is already existed in container, its value will be replaced.
+ * If not existed, creates new entry in container.
+ */
+void setString(struct PairContainer *container,
+               const uint8_t *key,
+               const uint8_t *value,
+               const int pad_len);
+
+/* merge all entries in src into dst. If key is duplicate, overwrite it.
+ */
+void mergeContainer(struct PairContainer *dst,
+                    const struct PairContainer *src);
+
+/* subtract src from dst.
+*/
+int subtractContainer(struct PairContainer *dst,
+                      const struct PairContainer *src);
+
+/* Given a container, encode its all entries into the buffer.
+ */
+int encodeContainer(const struct PairContainer *container,
+                    const int max_buf_len,
+                    uint8_t *buf,
+                    int *generated);
+
+/* Given a VPD blob, decode its entries and push into container.
+ */
+int decodeToContainer(struct PairContainer *container,
+                      const int32_t max_len,
+                      const uint8_t *input_buf,
+                      int32_t *consumed);
+
+/* Set filter for exporting functions.
+ * If filter is NULL, resets the filter so that everything can be exported.
+ */
+int setContainerFilter(struct PairContainer *container,
+                       const uint8_t *filter);
+
+/*
+ * Remove a key.
+ * Returns VPD_OK if deleted successfully. Otherwise, VPD_FAIL.
+ */
+int deleteKey(struct PairContainer *container,
+              const uint8_t *key);
+
+/*
+ * Returns number of pairs in container.
+ */
+int lenOfContainer(const struct PairContainer *container);
+
+/*
+ * Export the container content with human-readable text.
+ *
+ * The buf points to the first byte of buffer and *generated contains the number
+ * of bytes already existed in buffer.
+ *
+ * Afterward, the *generated will be plused on exact bytes this function has
+ * generated.
+ */
+int exportContainer(const int export_type,
+                    const struct PairContainer *container,
+                    const int max_buf_len,
+                    uint8_t *buf,
+                    int *generated);
+
+void destroyContainer(struct PairContainer *container);
+
+#endif  /* __LIB_VPD__ */

src/vendorcode/google/chromeos/vpd_decode.c

@@ -0,0 +1,85 @@
+/*
+ * 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.
+ *
+ */
+#include <assert.h>
+#include "lib_vpd.h"
+
+int decodeLen(
+    const int32_t max_len,
+    const uint8_t *in,
+    int32_t *length,
+    int32_t *decoded_len) {
+  uint8_t more;
+  int i = 0;
+
+  assert(length);
+  assert(decoded_len);
+
+  *length = 0;
+  do {
+    if (i >= max_len) return VPD_FAIL;
+    more = in[i] & 0x80;
+    *length <<= 7;
+    *length |= in[i] & 0x7f;
+    ++i;
+  } while (more);
+
+  *decoded_len = i;
+
+  return VPD_OK;
+}
+
+/* Sequentially decodes type, key, and value.
+ */
+int decodeVpdString(
+    const int32_t max_len,
+    const uint8_t *input_buf,
+    int32_t *consumed,
+    VpdDecodeCallback callback,
+    void *callback_arg) {
+  int type;
+  int32_t key_len, value_len;
+  int32_t decoded_len;
+  const uint8_t *key, *value;
+
+  /* type */
+  if (*consumed >= max_len)
+    return VPD_FAIL;
+
+  type = input_buf[*consumed];
+  switch (type) {
+    case VPD_TYPE_STRING:
+      (*consumed)++;
+
+      /* key */
+      if (VPD_OK != decodeLen(max_len - *consumed, &input_buf[*consumed],
+                              &key_len, &decoded_len) ||
+          *consumed + decoded_len >= max_len) {
+        return VPD_FAIL;
+      }
+
+      *consumed += decoded_len;
+      key = &input_buf[*consumed];
+      *consumed += key_len;
+
+      /* value */
+      if (VPD_OK != decodeLen(max_len - *consumed, &input_buf[*consumed],
+                              &value_len, &decoded_len) ||
+          *consumed + decoded_len > max_len) {
+        return VPD_FAIL;
+      }
+      *consumed += decoded_len;
+      value = &input_buf[*consumed];
+      *consumed += value_len;
+
+      return callback(key, key_len, value, value_len, callback_arg);
+
+    default:
+      return VPD_FAIL;
+      break;
+  }
+  return VPD_OK;
+}