OpenCellular/common/cbi.c

/* 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 "gpio.h"
#include "host_command.h"
#include "i2c.h"
#include "timer.h"
#include "util.h"

#define CPRINTS(format, args...) cprints(CC_SYSTEM, "CBI " format, ## args)

#define EEPROM_PAGE_WRITE_SIZE	16
#define EEPROM_PAGE_WRITE_MS	5
#define EC_ERROR_CBI_CACHE_INVALID	EC_ERROR_INTERNAL_FIRST

static int cached_read_result = EC_ERROR_CBI_CACHE_INVALID;
static uint8_t cbi[CBI_EEPROM_SIZE];
static struct cbi_header * const head = (struct cbi_header *)cbi;

static uint8_t cbi_crc8(const struct cbi_header *h)
{
	return crc8((uint8_t *)&h->crc + 1,
		    h->total_size - sizeof(h->magic) - sizeof(h->crc));
}

/*
 * Get board information from EEPROM
 */
static int do_read_board_info(void)
{
	uint8_t offset;

	CPRINTS("Reading board info");

	/* Read header */
	offset = 0;
	if (i2c_xfer(I2C_PORT_EEPROM, I2C_ADDR_EEPROM,
		     &offset, 1, cbi, sizeof(*head), I2C_XFER_SINGLE)) {
		CPRINTS("Failed to read header");
		return EC_ERROR_INVAL;
	}

	/* Check magic */
	if (memcmp(head->magic, cbi_magic, sizeof(head->magic))) {
		CPRINTS("Bad magic");
		return EC_ERROR_INVAL;
	}

	/* check version */
	if (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 (head->total_size < sizeof(*head) ||
			sizeof(cbi) < head->total_size) {
		CPRINTS("Bad size: %d", head->total_size);
		return EC_ERROR_OVERFLOW;
	}

	/* Read the data */
	offset = sizeof(*head);
	if (i2c_xfer(I2C_PORT_EEPROM, I2C_ADDR_EEPROM, &offset, 1,
		     head->data, head->total_size - sizeof(*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(head) != head->crc) {
		CPRINTS("Bad CRC");
		return EC_ERROR_INVAL;
	}

	return EC_SUCCESS;
}

static int read_board_info(void)
{
	if (cached_read_result == EC_ERROR_CBI_CACHE_INVALID) {
		cached_read_result = do_read_board_info();
		if (cached_read_result)
			/* On error (I2C or bad contents), retry a read */
			cached_read_result = do_read_board_info();
	}
	/* Else, we already tried and know the result. Return the cached
	 * error code immediately to avoid wasteful reads. */
	return cached_read_result;
}

static struct cbi_data *find_tag(enum cbi_data_tag tag)
{
	struct cbi_data *d;
	uint8_t *p;
	for (p = head->data; p + sizeof(*d) < cbi + head->total_size;) {
		d = (struct cbi_data *)p;
		if (d->tag == tag)
			return d;
		p += sizeof(*d) + d->size;
	}
	return NULL;
}

int cbi_get_board_info(enum cbi_data_tag tag, uint8_t *buf, uint8_t *size)
{
	const struct cbi_data *d;

	if (read_board_info())
		return EC_ERROR_UNKNOWN;

	d = find_tag(tag);
	if (!d)
		/* Not found */
		return EC_ERROR_UNKNOWN;
	if (*size < d->size)
		/* Insufficient buffer size */
		return EC_ERROR_INVAL;

	/* Clear the buffer in case len < *size */
	memset(buf, 0, *size);
	/* Copy the value */
	memcpy(buf, d->value, d->size);
	*size = d->size;
	return EC_SUCCESS;
}

int cbi_set_board_info(enum cbi_data_tag tag, const uint8_t *buf, uint8_t size)
{
	struct cbi_data *d;

	d = find_tag(tag);
	if (!d) {
		/* Not found. Check if new item would fit */
		if (sizeof(cbi) < head->total_size + sizeof(*d) + size)
			return EC_ERROR_OVERFLOW;
		/* Append new item */
		d = (struct cbi_data *)&cbi[head->total_size];
		d->tag = tag;
		d->size = size;
		memcpy(d->value, buf, d->size);
		head->total_size += (sizeof(*d) + size);
		return EC_SUCCESS;
	}
	/* No expand or shrink. Items are tightly packed. */
	if (d->size != size)
		return EC_ERROR_INVAL;
	/* Overwrite existing item */
	memcpy(d->value, buf, d->size);
	return EC_SUCCESS;
}

static int eeprom_is_write_protected(void)
{
	return !gpio_get_level(GPIO_WP_L);
}

static int write_board_info(void)
{
	/* The code is only tested for ST M24C02, whose page size for a single
	 * write is 16 byte. To support different EEPROMs, you may need to
	 * craft the i2c packets accordingly. */
	uint8_t buf[EEPROM_PAGE_WRITE_SIZE + 1];  /* '1' for offset byte */
	uint8_t *p = cbi;
	int rest = head->total_size;

	if (eeprom_is_write_protected()) {
		CPRINTS("Failed to write for WP");
		return EC_ERROR_ACCESS_DENIED;
	}

	buf[0] = 0;	/* Offset 0 */
	while (rest > 0) {
		int size = MIN(EEPROM_PAGE_WRITE_SIZE, rest);
		int rv;
		rest -= size;
		memcpy(&buf[1], p, size);
		rv = i2c_xfer(I2C_PORT_EEPROM, I2C_ADDR_EEPROM, buf, size + 1,
			      NULL, 0, I2C_XFER_SINGLE);
		if (rv) {
			CPRINTS("Failed to write for %d", rv);
			return rv;
		}
		/* Wait for internal write cycle completion */
		msleep(EEPROM_PAGE_WRITE_MS);
		buf[0] += size;
		p += size;
	}

	return EC_SUCCESS;
}

int cbi_get_board_version(uint32_t *ver)
{
	uint8_t size = sizeof(*ver);
	return cbi_get_board_info(CBI_TAG_BOARD_VERSION, (uint8_t *)ver, &size);
}

int cbi_get_sku_id(uint32_t *id)
{
	uint8_t size = sizeof(*id);
	return cbi_get_board_info(CBI_TAG_SKU_ID, (uint8_t *)id, &size);
}

int cbi_get_oem_id(uint32_t *id)
{
	uint8_t size = sizeof(*id);
	return cbi_get_board_info(CBI_TAG_OEM_ID, (uint8_t *)id, &size);
}

/*
 * For backward compatibility. New code should use cbi_get_board_version.
 */
int board_get_version(void)
{
	uint32_t ver;
	uint8_t size = sizeof(ver);
	if (cbi_get_board_info(CBI_TAG_BOARD_VERSION, (uint8_t *)&ver, &size))
		return -1;
	return ver;
}

static int hc_cbi_get(struct host_cmd_handler_args *args)
{
	const struct __ec_align4 ec_params_get_cbi *p = args->params;
	uint8_t size = MIN(args->response_max, UINT8_MAX);

	if (p->flag & CBI_GET_RELOAD)
		cached_read_result = EC_ERROR_CBI_CACHE_INVALID;

	if (cbi_get_board_info(p->tag, args->response, &size))
		return EC_RES_INVALID_PARAM;

	args->response_size = size;
	return EC_RES_SUCCESS;
}
DECLARE_HOST_COMMAND(EC_CMD_GET_CROS_BOARD_INFO,
		     hc_cbi_get,
		     EC_VER_MASK(0));

static int hc_cbi_set(struct host_cmd_handler_args *args)
{
	const struct __ec_align4 ec_params_set_cbi *p = args->params;
	int rv;

	if (p->flag & CBI_SET_INIT) {
		memset(cbi, 0, sizeof(cbi));
		memcpy(head->magic, cbi_magic, sizeof(cbi_magic));
		head->total_size = sizeof(*head);
		cached_read_result = EC_SUCCESS;
	} else {
		if (read_board_info())
			return EC_RES_ERROR;
	}

	if (cbi_set_board_info(p->tag, p->data, p->size))
		return EC_RES_INVALID_PARAM;

	/* Whether we're modifying existing data or creating new one,
	 * we take over the format. */
	head->major_version = CBI_VERSION_MAJOR;
	head->minor_version = CBI_VERSION_MINOR;
	head->crc = cbi_crc8(head);

	/* Skip write if client asks so. */
	if (p->flag & CBI_SET_NO_SYNC)
		return EC_RES_SUCCESS;

	rv = write_board_info();
	if (rv)
		return (rv == EC_ERROR_ACCESS_DENIED) ?
				EC_RES_ACCESS_DENIED : EC_RES_ERROR;

	return EC_RES_SUCCESS;
}
DECLARE_HOST_COMMAND(EC_CMD_SET_CROS_BOARD_INFO,
		     hc_cbi_set,
		     EC_VER_MASK(0));

static void dump_cbi(void)
{
	int i;
	for (i = 0; i < head->total_size; i++) {
		ccprintf(" %02x", cbi[i]);
		if (i % 16 == 15)
			ccprintf("\n");
	}
	ccprintf("\n");
}

static int command_dump_cbi(int argc, char **argv)
{
	uint32_t val;

	ccprintf("CBI_VERSION: 0x%04x\n", head->version);
	ccprintf("TOTAL_SIZE: %u\n", head->total_size);
	ccprintf("BOARD_VERSION: ");
	if (cbi_get_board_version(&val) == EC_SUCCESS)
		ccprintf("%u (0x%x)\n", val, val);
	else
		ccprintf("UNKNOWN\n");

	ccprintf("OEM_ID: ");
	if (cbi_get_oem_id(&val) == EC_SUCCESS)
		ccprintf("%u (0x%x)\n", val, val);
	else
		ccprintf("UNKNOWN\n");

	ccprintf("SKU_ID: ");
	if (cbi_get_sku_id(&val) == EC_SUCCESS)
		ccprintf("%u (0x%x)\n", val, val);
	else
		ccprintf("UNKNOWN\n");

	dump_cbi();
	return EC_SUCCESS;
}
DECLARE_CONSOLE_COMMAND(cbi, command_dump_cbi, NULL, NULL);