CBI: Read board info from EEPROM

This patch adds Cros Board Info APIs. It reads board info from EEPROM.
This patch sets CONFIG_CBI for Fizz to make it use CBI.

BUG=b:70294260
BRANCH=none
TEST=Read data from EEPROM.

Change-Id: I7eb4323188817d46b0450f1d65ac34d1b7e4e220
Reviewed-on: https://chromium-review.googlesource.com/707741
Commit-Ready: Daisuke Nojiri <dnojiri@chromium.org>
Tested-by: Daisuke Nojiri <dnojiri@chromium.org>
Reviewed-by: Daisuke Nojiri <dnojiri@chromium.org>

6 files changed, 203 insertions, 0 deletions

diff --git a/board/fizz/board.c b/board/fizz/board.c
index 2089777a01..9756aa05c0 100644
--- a/board/fizz/board.c
+++ b/board/fizz/board.c
@@ -17,6 +17,7 @@
 #include "charger.h"
 #include "chipset.h"
 #include "console.h"
+#include "cros_board_info.h"
 #include "driver/pmic_tps650x30.h"
 #include "driver/temp_sensor/tmp432.h"
 #include "driver/tcpm/ps8xxx.h"
@@ -449,6 +450,10 @@ DECLARE_HOOK(HOOK_AC_CHANGE, board_extpower, HOOK_PRIO_DEFAULT);
 /* Initialize board. */
 static void board_init(void)
 {
+	uint32_t version;
+	if (cbi_get_board_version(&version) == EC_SUCCESS)
+		CPRINTS("Board Version: 0x%04x", version);
+
 	/* Provide AC status to the PCH */
 	board_extpower();
 
diff --git a/board/fizz/board.h b/board/fizz/board.h
index 9409cfffb3..67b7d20aad 100644
--- a/board/fizz/board.h
+++ b/board/fizz/board.h
@@ -18,6 +18,9 @@
 /* EC */
 #define CONFIG_ADC
 #define CONFIG_BOARD_VERSION
+#define CONFIG_BOARD_SPECIFIC_VERSION
+#define CONFIG_CRC8
+#define CONFIG_CROS_BOARD_INFO
 #define CONFIG_DEDICATED_RECOVERY_BUTTON
 #define CONFIG_EMULATED_SYSRQ
 #define CONFIG_LED_COMMON
@@ -130,6 +133,7 @@
 
 /* I2C addresses */
 #define I2C_ADDR_TCPC0		0x16
+#define I2C_ADDR_EEPROM		0xa0
 
 /* Verify and jump to RW image on boot */
 #define CONFIG_VBOOT_EFS
diff --git a/common/build.mk b/common/build.mk
index 589c71bf3c..7b70378541 100644
--- a/common/build.mk
+++ b/common/build.mk
@@ -26,6 +26,7 @@ common-$(CONFIG_BLUETOOTH_LE)+=bluetooth_le.o
 common-$(CONFIG_BLUETOOTH_LE_STACK)+=btle_hci_controller.o btle_ll.o
 common-$(CONFIG_CAPSENSE)+=capsense.o
 common-$(CONFIG_CASE_CLOSED_DEBUG_V1)+=ccd_config.o
+common-$(CONFIG_CROS_BOARD_INFO)+=cbi.o
 common-$(CONFIG_CHARGE_MANAGER)+=charge_manager.o
 common-$(CONFIG_CHARGE_RAMP_HW)+=charge_ramp.o
 common-$(CONFIG_CHARGE_RAMP_SW)+=charge_ramp.o charge_ramp_sw.o
diff --git a/common/cbi.c b/common/cbi.c
new file mode 100644
index 0000000000..dce8475d81
--- /dev/null
+++ b/common/cbi.c
@@ -0,0 +1,127 @@
+/* Copyright 2018 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.
+ *
+ * Cros Board Info
+ */
+
+#include "common.h"
+#include "console.h"
+#include "crc8.h"
+#include "cros_board_info.h"
+#include "i2c.h"
+#include "util.h"
+
+#define CPRINTS(format, args...) cprints(CC_SYSTEM, "CBI " format, ## args)
+
+static struct board_info bi;
+/* TODO: Init it to -1. On error (I2C or bad contents), retry a read and set it
+ * to enum ec_error_list if it still fails. The successive calls can be
+ * immediately returned with the cached error code. This will avoid attempting
+ * reads doomed to fail. */
+static int initialized;
+
+static uint8_t cbi_crc8(const struct board_info *bi)
+{
+	return crc8((uint8_t *)&bi->head.crc + 1, bi->head.total_size - 4);
+}
+
+/*
+ * Get board information from EEPROM
+ */
+static int read_board_info(void)
+{
+	uint8_t buf[256];
+	uint8_t offset;
+
+	if (initialized)
+		return EC_SUCCESS;
+
+	CPRINTS("Reading board info");
+
+	/* Read header */
+	offset = 0;
+	if (i2c_xfer(I2C_PORT_EEPROM, I2C_ADDR_EEPROM,
+		     &offset, 1, buf, sizeof(bi.head), I2C_XFER_SINGLE)) {
+		CPRINTS("Failed to read header");
+		return EC_ERROR_INVAL;
+	}
+	memcpy(&bi.head, buf, sizeof(bi.head));
+
+	/* Check magic */
+	if (memcmp(bi.head.magic, cbi_magic, sizeof(bi.head.magic))) {
+		CPRINTS("Bad magic");
+		return EC_ERROR_INVAL;
+	}
+
+	/* check version */
+	if (bi.head.major_version > CBI_VERSION_MAJOR) {
+		CPRINTS("Version mismatch");
+		return EC_ERROR_INVAL;
+	}
+
+	/* Check the data size. It's expected to support up to 64k but our
+	 * buffer has practical limitation. */
+	if (bi.head.total_size < sizeof(bi) ||
+			bi.head.total_size > sizeof(buf)) {
+		CPRINTS("Bad size: %d", bi.head.total_size);
+		return EC_ERROR_OVERFLOW;
+	}
+
+	/* Read the rest */
+	offset = sizeof(bi.head);
+	if (i2c_xfer(I2C_PORT_EEPROM, I2C_ADDR_EEPROM, &offset, 1,
+		     buf + sizeof(bi.head),
+		     bi.head.total_size - sizeof(bi.head),
+		     I2C_XFER_SINGLE)) {
+		CPRINTS("Failed to read body");
+		return EC_ERROR_INVAL;
+	}
+
+	/* Check CRC. This supports new fields unknown to this parser. */
+	if (cbi_crc8((struct board_info *)&buf) != bi.head.crc) {
+		CPRINTS("Bad CRC");
+		return EC_ERROR_INVAL;
+	}
+
+	/* Save only the data we understand. */
+	memcpy(&bi.head + 1, &buf[sizeof(bi.head)],
+	       sizeof(bi) - sizeof(bi.head));
+	/* If we're handling previous version, clear all new fields */
+
+	initialized = 1;
+
+	return EC_SUCCESS;
+}
+
+int cbi_get_board_version(uint32_t *version)
+{
+	if (read_board_info())
+		return EC_ERROR_UNKNOWN;
+	*version = bi.version;
+	return EC_SUCCESS;
+}
+
+int cbi_get_sku_id(uint32_t *sku_id)
+{
+	if (read_board_info())
+		return EC_ERROR_UNKNOWN;
+	*sku_id = bi.sku_id;
+	return EC_SUCCESS;
+}
+
+int cbi_get_oem_id(uint32_t *oem_id)
+{
+	if (read_board_info())
+		return EC_ERROR_UNKNOWN;
+	*oem_id = bi.oem_id;
+	return EC_SUCCESS;
+}
+
+int board_get_version(void)
+{
+	uint32_t version;
+	if (cbi_get_board_version(&version))
+		return -1;
+	return version;
+}
diff --git a/include/config.h b/include/config.h
index 5126164767..cb2dc59f81 100644
--- a/include/config.h
+++ b/include/config.h
@@ -3118,6 +3118,12 @@
  */
 #undef CONFIG_BOARD_ID_SUPPORT
 
+/*
+ * Define this to enable Cros Board Info support. I2C_EEPROM_PORT and
+ * I2C_EEPROM_ADDR must be defined as well.
+ */
+#undef CONFIG_CROS_BOARD_INFO
+
 /*****************************************************************************/
 /*
  * Include board and core configs, since those hold the CONFIG_ constants for a
diff --git a/include/cros_board_info.h b/include/cros_board_info.h
new file mode 100644
index 0000000000..8d140f1d25
--- /dev/null
+++ b/include/cros_board_info.h
@@ -0,0 +1,60 @@
+/* Copyright 2018 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.
+ *
+ * Cros Board Info
+ */
+#ifndef __CROS_EC_CROS_BOARD_INFO_H
+#define __CROS_EC_CROS_BOARD_INFO_H
+
+#include "common.h"
+
+#define CBI_VERSION_MAJOR 0
+#define CBI_VERSION_MINOR 0
+static const uint8_t cbi_magic[] = { 0x43, 0x42, 0x49 };  /* 'C' 'B' 'I' */
+
+struct cbi_header {
+	uint8_t magic[3];
+	/* CRC of 'struct board_info' excluding magic and crc */
+	uint8_t crc;
+	/* Data format version. Parsers are expected to process data as long
+	 * as major version is equal or younger. */
+	union {
+		struct {
+			uint8_t minor_version;
+			uint8_t major_version;
+		};
+		uint16_t version;
+	};
+	/* Total size of data. It can be larger than sizeof(struct board_info)
+	 * if future versions add additional fields. */
+	uint16_t total_size;
+} __attribute__((packed));
+
+struct board_info {
+	struct cbi_header head;
+	/* Board version */
+	union {
+		struct {
+			uint8_t minor_version;
+			uint8_t major_version;
+		};
+		uint16_t version;
+	};
+	/* OEM ID */
+	uint8_t oem_id;
+	/* SKU ID */
+	uint8_t sku_id;
+} __attribute__((packed));
+
+/**
+ * Board info accessors
+ *
+ * @param version/sku_id/oem_id [OUT] Data read from EEPROM
+ * @return EC_SUCCESS on success or EC_ERROR_* otherwise.
+ */
+int cbi_get_board_version(uint32_t *version);
+int cbi_get_sku_id(uint32_t *sku_id);
+int cbi_get_oem_id(uint32_t *oem_id);
+
+#endif /* __CROS_EC_CROS_BOARD_INFO_H */