path: root/board/cr50/board_id.c

/* Copyright 2017 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 "common.h"
#include "board_id.h"
#include "endian.h"
#include "extension.h"
#include "flash_info.h"
#include "signed_header.h"
#include "system.h"
#include "util.h"

#define CPRINTS(format, args...) cprints(CC_RBOX, format, ## args)
#define CPRINTF(format, args...) cprintf(CC_RBOX, format, ## args)

/**
 * Return the image header for the current image copy
 */
const struct SignedHeader *get_current_image_header(void)
{
	return (const struct SignedHeader *)
			get_program_memory_addr(system_get_image_copy());
}

/**
 * Check the current header vs. the supplied Board ID
 *
 * @param board_id	Pointer to a Board ID structure to check
 * @param h		Pointer to the currently running image's header
 *
 * @return 0 if no mismatch, non-zero if mismatch
 */
static uint32_t check_board_id_vs_header(const struct board_id *id,
					 const struct SignedHeader *h)
{
	uint32_t mismatch;
	uint32_t header_board_id_type;
	uint32_t header_board_id_mask;
	uint32_t header_board_id_flags;

	/* Blank Board ID matches all headers */
	if (~(id->type & id->type_inv & id->flags) == 0)
		return 0;

	header_board_id_type = SIGNED_HEADER_PADDING ^ h->board_id_type;
	header_board_id_mask = SIGNED_HEADER_PADDING ^ h->board_id_type_mask;
	header_board_id_flags = SIGNED_HEADER_PADDING ^ h->board_id_flags;

	/* Blank header means this is a common image, can run on any device. */
	if ((header_board_id_type |
	     header_board_id_mask |
	     header_board_id_flags) == 0)
		return 0;

	/*
	 * Masked bits in header Board ID type must match type and inverse from
	 * flash.
	 */
	mismatch = header_board_id_type ^ id->type;
	mismatch |= header_board_id_type ^ ~id->type_inv;
	mismatch &= header_board_id_mask;

	/*
	 * All 1-bits in header Board ID flags must be present in flags from
	 * flash
	 */
	mismatch |=
		((header_board_id_flags & id->flags) != header_board_id_flags);

	return mismatch;
}

/**
 * Check board ID from the flash INFO1 space.
 *
 * @param id	Pointer to a Board ID structure to fill
 *
 * @return EC_SUCCESS of an error code in cases of vairous failures to read.
 */
static int read_board_id(struct board_id *id)
{
	uint32_t *id_p;
	int i;

	/*
	 * Board ID structure size is guaranteed to be divisible by 4, and it
	 * is guaranteed to be aligned at 4 bytes.
	 */

	id_p = (uint32_t *)id;

	/* Make sure INFO1 board ID space is readable */
	if (flash_info_read_enable(INFO_BOARD_SPACE_OFFSET,
				   INFO_BOARD_SPACE_PROTECT_SIZE) !=
	    EC_SUCCESS) {
		CPRINTS("%s: failed to enable read access to info", __func__);
		return EC_ERROR_ACCESS_DENIED;
	}

	for (i = 0; i < sizeof(*id); i += sizeof(uint32_t)) {
		int rv;

		rv = flash_physical_info_read_word
			(INFO_BOARD_SPACE_OFFSET +
			 offsetof(struct info1_board_space, bid) + i,
			 id_p);
		if (rv != EC_SUCCESS) {
			CPRINTF("%s: failed to read word %d, error %d\n",
				i, rv);
			return rv;
		}
		id_p++;
	}
	return EC_SUCCESS;
}

/**
 * Write board ID into the flash INFO1 space.
 *
 * @param id	Pointer to a Board ID structure to copy into INFO1
 *
 * @return EC_SUCCESS or an error code in cases of various failures to read or
 *              if the space has been already initialized.
 */
static int write_board_id(const struct board_id *id)
{
	struct board_id id_test;
	uint32_t rv;

	/*
	 * Make sure the current header will still validate against the
	 * proposed values.  If it doesn't, then programming these values
	 * would cause the next boot to fail.
	 */
	if (check_board_id_vs_header(id, get_current_image_header()) != 0) {
		CPRINTS("%s: Board ID wouldn't allow current header", __func__);
		return EC_ERROR_INVAL;
	}

	/* Fail if Board ID is already programmed */
	rv = read_board_id(&id_test);
	if (rv != EC_SUCCESS) {
		CPRINTS("%s: error reading Board ID", __func__);
		return rv;
	}

	if (~(id_test.type & id_test.type_inv & id_test.flags) != 0) {
		CPRINTS("%s: Board ID already programmed", __func__);
		return EC_ERROR_ACCESS_DENIED;
	}

	/* Enable write access */
	if (flash_info_write_enable(INFO_BOARD_SPACE_OFFSET,
				    INFO_BOARD_SPACE_PROTECT_SIZE) !=
	    EC_SUCCESS) {
		CPRINTS("%s: failed to enable write access", __func__);
		return EC_ERROR_ACCESS_DENIED;
	}

	/* Write Board ID */
	rv = flash_info_physical_write(INFO_BOARD_SPACE_OFFSET +
			 offsetof(struct info1_board_space, bid),
				       sizeof(*id), (const char *)id);
	if (rv != EC_SUCCESS)
		CPRINTS("%s: write failed", __func__);

	/* Disable write access */
	flash_info_write_disable();

	return rv;
}

static enum vendor_cmd_rc vc_set_board_id(enum vendor_cmd_cc code,
					  void *buf,
					  size_t input_size,
					  size_t *response_size)
{
	struct board_id id;
	uint8_t *pbuf = buf;

	*response_size = 1;

	/* Exactly two fields are expected. */
	if (input_size != sizeof(id.type) + sizeof(id.flags)) {
		*pbuf = VENDOR_RC_BOGUS_ARGS;
		return VENDOR_RC_BOGUS_ARGS;
	}

	memcpy(&id.type, pbuf, sizeof(id.type));
	id.type = be32toh(id.type);
	id.type_inv = ~id.type;

	memcpy(&id.flags, pbuf + sizeof(id.type), sizeof(id.flags));
	id.flags = be32toh(id.flags);

	/* We care about the LSB only. */
	*pbuf = write_board_id(&id);

	return *pbuf;
}
DECLARE_VENDOR_COMMAND(VENDOR_CC_SET_BOARD_ID, vc_set_board_id);

static int command_board_id(int argc, char **argv)
{
	struct board_id id;
	int rv = EC_ERROR_PARAM_COUNT;

	if (argc == 1) {
		rv = read_board_id(&id);

		if (rv != EC_SUCCESS) {
			ccprintf("Failed to read board ID space\n");
			return rv;
		}
		ccprintf("Board ID: %08x, flags %08x\n", id.type, id.flags);

		if ((~id.type | ~id.type_inv | ~id.flags) == 0)
			return rv; /* The space is not initialized. */

		if (id.type != ~id.type_inv)
			ccprintf("Inv Type Mismatch (%08x instead of %08x)!\n",
				 id.type_inv, ~id.type);
	}
#ifdef CR50_DEV
	else if (argc == 3) {
		char *e;

		id.type = strtoi(argv[1], &e, 0);
		if (*e)
			return EC_ERROR_PARAM1;
		id.type_inv = ~id.type;
		id.flags = strtoi(argv[2], &e, 0);
		if (*e)
			return EC_ERROR_PARAM2;

		rv = write_board_id(&id);
	} else {
		ccprintf("specify board type and flags\n");
		rv = EC_ERROR_PARAM_COUNT;
	}
#endif
	return rv;
}
DECLARE_SAFE_CONSOLE_COMMAND(bid,
			     command_board_id, NULL, "Set/Get Board ID");

static enum vendor_cmd_rc vc_get_board_id(enum vendor_cmd_cc code,
					  void *buf,
					  size_t input_size,
					  size_t *response_size)
{
	struct board_id id;

	if (read_board_id(&id))
		return VENDOR_RC_READ_FLASH_FAIL;

	/* Convert to line representation. */
	id.type = htobe32(id.type);
	id.type_inv = htobe32(id.type_inv);
	id.flags = htobe32(id.flags);

	memcpy(buf, &id, sizeof(id));
	*response_size = sizeof(id);

	return VENDOR_RC_SUCCESS;
}
DECLARE_VENDOR_COMMAND(VENDOR_CC_GET_BOARD_ID, vc_get_board_id);