board: ge: bx50v3: set eth0 MAC address

Define i2c mux configuration.  Add new vpd_reader which is used to read
vital product data.  Read VPD from EEPROM and set eth0 MAC address.

Signed-off-by: Ian Ray <ian.ray@ge.com>
Signed-off-by: Jose Alarcon <jose.alarcon@ge.com>
diff --git a/board/ge/bx50v3/vpd_reader.c b/board/ge/bx50v3/vpd_reader.c
new file mode 100644
index 0000000..98da893
--- /dev/null
+++ b/board/ge/bx50v3/vpd_reader.c
@@ -0,0 +1,228 @@
+/*
+ * Copyright 2016 General Electric Company
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include "vpd_reader.h"
+
+#include <linux/bch.h>
+#include <stdlib.h>
+
+
+/* BCH configuration */
+
+const struct {
+	int header_ecc_capability_bits;
+	int data_ecc_capability_bits;
+	unsigned int prim_poly;
+	struct {
+		int min;
+		int max;
+	} galois_field_order;
+} bch_configuration = {
+	.header_ecc_capability_bits = 4,
+	.data_ecc_capability_bits = 16,
+	.prim_poly = 0,
+	.galois_field_order = {
+		.min = 5,
+		.max = 15,
+	},
+};
+
+static int calculate_galois_field_order(size_t source_length)
+{
+	int gfo = bch_configuration.galois_field_order.min;
+
+	for (; gfo < bch_configuration.galois_field_order.max &&
+	     ((((1 << gfo) - 1) - ((int)source_length * 8)) < 0);
+	     gfo++) {
+	}
+
+	if (gfo == bch_configuration.galois_field_order.max) {
+		return -1;
+	}
+
+	return gfo + 1;
+}
+
+static int verify_bch(int ecc_bits, unsigned int prim_poly,
+	uint8_t * data, size_t data_length,
+	const uint8_t * ecc, size_t ecc_length)
+{
+	int gfo = calculate_galois_field_order(data_length);
+	if (gfo < 0) {
+		return -1;
+	}
+
+	struct bch_control * bch = init_bch(gfo, ecc_bits, prim_poly);
+	if (!bch) {
+		return -1;
+	}
+
+	if (bch->ecc_bytes != ecc_length) {
+		free_bch(bch);
+		return -1;
+	}
+
+	unsigned * errloc = (unsigned *)calloc(data_length, sizeof(unsigned));
+	int errors = decode_bch(
+			bch, data, data_length, ecc, NULL, NULL, errloc);
+	free_bch(bch);
+	if (errors < 0) {
+		free(errloc);
+		return -1;
+	}
+
+	if (errors > 0) {
+		for (int n = 0; n < errors; n++) {
+			if (errloc[n] >= 8 * data_length) {
+				/* n-th error located in ecc (no need for data correction) */
+			} else {
+				/* n-th error located in data */
+				data[errloc[n] / 8] ^= 1 << (errloc[n] % 8);
+			}
+		}
+	}
+
+	free(errloc);
+	return 0;
+}
+
+
+static const int ID = 0;
+static const int LEN = 1;
+static const int VER = 2;
+static const int TYP = 3;
+static const int BLOCK_SIZE = 4;
+
+static const uint8_t HEADER_BLOCK_ID = 0x00;
+static const uint8_t HEADER_BLOCK_LEN = 18;
+static const uint32_t HEADER_BLOCK_MAGIC = 0xca53ca53;
+static const size_t HEADER_BLOCK_VERIFY_LEN = 14;
+static const size_t HEADER_BLOCK_ECC_OFF = 14;
+static const size_t HEADER_BLOCK_ECC_LEN = 4;
+
+static const uint8_t ECC_BLOCK_ID = 0xFF;
+
+int vpd_reader(
+	size_t size,
+	uint8_t * data,
+	void * userdata,
+	int (*fn)(
+	    void * userdata,
+	    uint8_t id,
+	    uint8_t version,
+	    uint8_t type,
+	    size_t size,
+	    uint8_t const * data))
+{
+	if (   size < HEADER_BLOCK_LEN
+	    || data == NULL
+	    || fn == NULL) {
+		return -EINVAL;
+	}
+
+	/*
+	 * +--------------------+--------------------+--//--+--------------------+
+	 * | header block       | data block         | ...  | ecc block          |
+	 * +--------------------+--------------------+--//--+--------------------+
+	 * :                    :                           :
+	 * +------+-------+-----+                           +------+-------------+
+	 * | id   | magic | ecc |                           | ...  | ecc         |
+	 * | len  | off   |     |                           +------+-------------+
+	 * | ver  | size  |     |                           :
+	 * | type |       |     |                           :
+	 * +------+-------+-----+                           :
+	 * :              :     :                           :
+	 * <----- [1] ---->     <----------- [2] ----------->
+	 *
+	 * Repair (if necessary) the contents of header block [1] by using a
+	 * 4 byte ECC located at the end of the header block.  A successful
+	 * return value means that we can trust the header.
+	 */
+	int ret = verify_bch(
+		bch_configuration.header_ecc_capability_bits,
+		bch_configuration.prim_poly,
+		data,
+		HEADER_BLOCK_VERIFY_LEN,
+		&data[HEADER_BLOCK_ECC_OFF],
+		HEADER_BLOCK_ECC_LEN);
+	if (ret < 0) {
+		return ret;
+	}
+
+	/* Validate header block { id, length, version, type }. */
+	if (   data[ID] != HEADER_BLOCK_ID
+	    || data[LEN] != HEADER_BLOCK_LEN
+	    || data[VER] != 0
+	    || data[TYP] != 0
+	    || ntohl(*(uint32_t *)(&data[4])) != HEADER_BLOCK_MAGIC) {
+		return -EINVAL;
+	}
+
+	uint32_t offset = ntohl(*(uint32_t *)(&data[8]));
+	uint16_t size_bits = ntohs(*(uint16_t *)(&data[12]));
+
+	/* Check that ECC header fits. */
+	if (offset + 3 >= size) {
+		return -EINVAL;
+	}
+
+	/* Validate ECC block. */
+	uint8_t * ecc = &data[offset];
+	if (   ecc[ID] != ECC_BLOCK_ID
+	    || ecc[LEN] < BLOCK_SIZE
+	    || ecc[LEN] + offset > size
+	    || ecc[LEN] - BLOCK_SIZE != size_bits / 8
+	    || ecc[VER] != 1
+	    || ecc[TYP] != 1) {
+		return -EINVAL;
+	}
+
+	/*
+	 * Use the header block to locate the ECC block and verify the data
+	 * blocks [2] against the ecc block ECC.
+	 */
+	ret = verify_bch(
+		bch_configuration.data_ecc_capability_bits,
+		bch_configuration.prim_poly,
+		&data[data[LEN]],
+		offset - data[LEN],
+		&data[offset + BLOCK_SIZE],
+		ecc[LEN] - BLOCK_SIZE);
+	if (ret < 0) {
+		return ret;
+	}
+
+	/* Stop after ECC.  Ignore possible zero padding. */
+	size = offset;
+
+	for (;;) {
+		/* Move to next block. */
+		size -= data[LEN];
+		data += data[LEN];
+
+		if (size == 0) {
+			/* Finished iterating through blocks. */
+			return 0;
+		}
+
+		if (   size < BLOCK_SIZE
+		    || data[LEN] < BLOCK_SIZE) {
+			/* Not enough data for a header, or short header. */
+			return -EINVAL;
+		}
+
+		ret = fn(
+			userdata,
+			data[ID],
+			data[VER],
+			data[TYP],
+			data[LEN] - BLOCK_SIZE,
+			&data[BLOCK_SIZE]);
+		if (ret) {
+			return ret;
+		}
+	}
+}