cros_ec.c

/*
 * Chromium OS cros_ec driver
 *
 * Copyright (c) 2012 The Chromium OS Authors.
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */

/*
 * The Matrix Keyboard Protocol driver handles talking to the keyboard
 * controller chip. Mostly this is for keyboard functions, but some other
 * things have slipped in, so we provide generic services to talk to the
 * KBC.
 */

#include <common.h>
#include <command.h>
#include <i2c.h>
#include <cros_ec.h>
#include <fdtdec.h>
#include <malloc.h>
#include <spi.h>
#include <asm/io.h>
#include <asm-generic/gpio.h>

#ifdef DEBUG_TRACE
#define debug_trace(fmt, b...)	debug(fmt, #b)
#else
#define debug_trace(fmt, b...)
#endif

enum {
	/* Timeout waiting for a flash erase command to complete */
	CROS_EC_CMD_TIMEOUT_MS	= 5000,
	/* Timeout waiting for a synchronous hash to be recomputed */
	CROS_EC_CMD_HASH_TIMEOUT_MS = 2000,
};

static struct cros_ec_dev static_dev, *last_dev;

DECLARE_GLOBAL_DATA_PTR;

/* Note: depends on enum ec_current_image */
static const char * const ec_current_image_name[] = {"unknown", "RO", "RW"};

void cros_ec_dump_data(const char *name, int cmd, const uint8_t *data, int len)
{
#ifdef DEBUG
	int i;

	printf("%s: ", name);
	if (cmd != -1)
		printf("cmd=%#x: ", cmd);
	for (i = 0; i < len; i++)
		printf("%02x ", data[i]);
	printf("\n");
#endif
}

/*
 * Calculate a simple 8-bit checksum of a data block
 *
 * @param data	Data block to checksum
 * @param size	Size of data block in bytes
 * @return checksum value (0 to 255)
 */
int cros_ec_calc_checksum(const uint8_t *data, int size)
{
	int csum, i;

	for (i = csum = 0; i < size; i++)
		csum += data[i];
	return csum & 0xff;
}

static int send_command(struct cros_ec_dev *dev, uint8_t cmd, int cmd_version,
			const void *dout, int dout_len,
			uint8_t **dinp, int din_len)
{
	int ret;

	switch (dev->interface) {
#ifdef CONFIG_CROS_EC_SPI
	case CROS_EC_IF_SPI:
		ret = cros_ec_spi_command(dev, cmd, cmd_version,
					(const uint8_t *)dout, dout_len,
					dinp, din_len);
		break;
#endif
#ifdef CONFIG_CROS_EC_I2C
	case CROS_EC_IF_I2C:
		ret = cros_ec_i2c_command(dev, cmd, cmd_version,
					(const uint8_t *)dout, dout_len,
					dinp, din_len);
		break;
#endif
#ifdef CONFIG_CROS_EC_LPC
	case CROS_EC_IF_LPC:
		ret = cros_ec_lpc_command(dev, cmd, cmd_version,
					(const uint8_t *)dout, dout_len,
					dinp, din_len);
		break;
#endif
	case CROS_EC_IF_NONE:
	default:
		ret = -1;
	}

	return ret;
}

/**
 * Send a command to the CROS-EC device and return the reply.
 *
 * The device's internal input/output buffers are used.
 *
 * @param dev		CROS-EC device
 * @param cmd		Command to send (EC_CMD_...)
 * @param cmd_version	Version of command to send (EC_VER_...)
 * @param dout          Output data (may be NULL If dout_len=0)
 * @param dout_len      Size of output data in bytes
 * @param dinp          Response data (may be NULL If din_len=0).
 *			If not NULL, it will be updated to point to the data
 *			and will always be double word aligned (64-bits)
 * @param din_len       Maximum size of response in bytes
 * @return number of bytes in response, or -1 on error
 */
static int ec_command_inptr(struct cros_ec_dev *dev, uint8_t cmd,
		int cmd_version, const void *dout, int dout_len, uint8_t **dinp,
		int din_len)
{
	uint8_t *din;
	int len;

	len = send_command(dev, cmd, cmd_version, dout, dout_len,
				&din, din_len);

	/* If the command doesn't complete, wait a while */
	if (len == -EC_RES_IN_PROGRESS) {
		struct ec_response_get_comms_status *resp;
		ulong start;

		/* Wait for command to complete */
		start = get_timer(0);
		do {
			int ret;

			mdelay(50);	/* Insert some reasonable delay */
			ret = send_command(dev, EC_CMD_GET_COMMS_STATUS, 0,
					NULL, 0,
					(uint8_t **)&resp, sizeof(*resp));
			if (ret < 0)
				return ret;

			if (get_timer(start) > CROS_EC_CMD_TIMEOUT_MS) {
				debug("%s: Command %#02x timeout\n",
				      __func__, cmd);
				return -EC_RES_TIMEOUT;
			}
		} while (resp->flags & EC_COMMS_STATUS_PROCESSING);

		/* OK it completed, so read the status response */
		/* not sure why it was 0 for the last argument */
		len = send_command(dev, EC_CMD_RESEND_RESPONSE, 0,
				NULL, 0, &din, din_len);
	}

	debug("%s: len=%d, dinp=%p, *dinp=%p\n", __func__, len, dinp, *dinp);
	if (dinp) {
		/* If we have any data to return, it must be 64bit-aligned */
		assert(len <= 0 || !((uintptr_t)din & 7));
		*dinp = din;
	}

	return len;
}

/**
 * Send a command to the CROS-EC device and return the reply.
 *
 * The device's internal input/output buffers are used.
 *
 * @param dev		CROS-EC device
 * @param cmd		Command to send (EC_CMD_...)
 * @param cmd_version	Version of command to send (EC_VER_...)
 * @param dout          Output data (may be NULL If dout_len=0)
 * @param dout_len      Size of output data in bytes
 * @param din           Response data (may be NULL If din_len=0).
 *			It not NULL, it is a place for ec_command() to copy the
 *      data to.
 * @param din_len       Maximum size of response in bytes
 * @return number of bytes in response, or -1 on error
 */
static int ec_command(struct cros_ec_dev *dev, uint8_t cmd, int cmd_version,
		      const void *dout, int dout_len,
		      void *din, int din_len)
{
	uint8_t *in_buffer;
	int len;

	assert((din_len == 0) || din);
	len = ec_command_inptr(dev, cmd, cmd_version, dout, dout_len,
			&in_buffer, din_len);
	if (len > 0) {
		/*
		 * If we were asked to put it somewhere, do so, otherwise just
		 * disregard the result.
		 */
		if (din && in_buffer) {
			assert(len <= din_len);
			memmove(din, in_buffer, len);
		}
	}
	return len;
}

int cros_ec_scan_keyboard(struct cros_ec_dev *dev, struct mbkp_keyscan *scan)
{
	if (ec_command(dev, EC_CMD_CROS_EC_STATE, 0, NULL, 0, scan,
		       sizeof(scan->data)) < sizeof(scan->data))
		return -1;

	return 0;
}

int cros_ec_read_id(struct cros_ec_dev *dev, char *id, int maxlen)
{
	struct ec_response_get_version *r;

	if (ec_command_inptr(dev, EC_CMD_GET_VERSION, 0, NULL, 0,
			(uint8_t **)&r, sizeof(*r)) < sizeof(*r))
		return -1;

	if (maxlen > sizeof(r->version_string_ro))
		maxlen = sizeof(r->version_string_ro);

	switch (r->current_image) {
	case EC_IMAGE_RO:
		memcpy(id, r->version_string_ro, maxlen);
		break;
	case EC_IMAGE_RW:
		memcpy(id, r->version_string_rw, maxlen);
		break;
	default:
		return -1;
	}

	id[maxlen - 1] = '\0';
	return 0;
}

int cros_ec_read_version(struct cros_ec_dev *dev,
		       struct ec_response_get_version **versionp)
{
	if (ec_command_inptr(dev, EC_CMD_GET_VERSION, 0, NULL, 0,
			(uint8_t **)versionp, sizeof(**versionp))
			< sizeof(**versionp))
		return -1;

	return 0;
}

int cros_ec_read_build_info(struct cros_ec_dev *dev, char **strp)
{
	if (ec_command_inptr(dev, EC_CMD_GET_BUILD_INFO, 0, NULL, 0,
			(uint8_t **)strp, EC_HOST_PARAM_SIZE) < 0)
		return -1;

	return 0;
}

int cros_ec_read_current_image(struct cros_ec_dev *dev,
		enum ec_current_image *image)
{
	struct ec_response_get_version *r;

	if (ec_command_inptr(dev, EC_CMD_GET_VERSION, 0, NULL, 0,
			(uint8_t **)&r, sizeof(*r)) < sizeof(*r))
		return -1;

	*image = r->current_image;
	return 0;
}

static int cros_ec_wait_on_hash_done(struct cros_ec_dev *dev,
				  struct ec_response_vboot_hash *hash)
{
	struct ec_params_vboot_hash p;
	ulong start;

	start = get_timer(0);
	while (hash->status == EC_VBOOT_HASH_STATUS_BUSY) {
		mdelay(50);	/* Insert some reasonable delay */

		p.cmd = EC_VBOOT_HASH_GET;
		if (ec_command(dev, EC_CMD_VBOOT_HASH, 0, &p, sizeof(p),
		       hash, sizeof(*hash)) < 0)
			return -1;

		if (get_timer(start) > CROS_EC_CMD_HASH_TIMEOUT_MS) {
			debug("%s: EC_VBOOT_HASH_GET timeout\n", __func__);
			return -EC_RES_TIMEOUT;
		}
	}
	return 0;
}


int cros_ec_read_hash(struct cros_ec_dev *dev,
		struct ec_response_vboot_hash *hash)
{
	struct ec_params_vboot_hash p;
	int rv;

	p.cmd = EC_VBOOT_HASH_GET;
	if (ec_command(dev, EC_CMD_VBOOT_HASH, 0, &p, sizeof(p),
		       hash, sizeof(*hash)) < 0)
		return -1;

	/* If the EC is busy calculating the hash, fidget until it's done. */
	rv = cros_ec_wait_on_hash_done(dev, hash);
	if (rv)
		return rv;

	/* If the hash is valid, we're done. Otherwise, we have to kick it off
	 * again and wait for it to complete. Note that we explicitly assume
	 * that hashing zero bytes is always wrong, even though that would
	 * produce a valid hash value. */
	if (hash->status == EC_VBOOT_HASH_STATUS_DONE && hash->size)
		return 0;

	debug("%s: No valid hash (status=%d size=%d). Compute one...\n",
	      __func__, hash->status, hash->size);

	p.cmd = EC_VBOOT_HASH_RECALC;
	p.hash_type = EC_VBOOT_HASH_TYPE_SHA256;
	p.nonce_size = 0;
	p.offset = EC_VBOOT_HASH_OFFSET_RW;

	if (ec_command(dev, EC_CMD_VBOOT_HASH, 0, &p, sizeof(p),
		       hash, sizeof(*hash)) < 0)
		return -1;

	rv = cros_ec_wait_on_hash_done(dev, hash);
	if (rv)
		return rv;

	debug("%s: hash done\n", __func__);

	return 0;
}

static int cros_ec_invalidate_hash(struct cros_ec_dev *dev)
{
	struct ec_params_vboot_hash p;
	struct ec_response_vboot_hash *hash;

	/* We don't have an explict command for the EC to discard its current
	 * hash value, so we'll just tell it to calculate one that we know is
	 * wrong (we claim that hashing zero bytes is always invalid).
	 */
	p.cmd = EC_VBOOT_HASH_RECALC;
	p.hash_type = EC_VBOOT_HASH_TYPE_SHA256;
	p.nonce_size = 0;
	p.offset = 0;
	p.size = 0;

	debug("%s:\n", __func__);

	if (ec_command_inptr(dev, EC_CMD_VBOOT_HASH, 0, &p, sizeof(p),
		       (uint8_t **)&hash, sizeof(*hash)) < 0)
		return -1;

	/* No need to wait for it to finish */
	return 0;
}

int cros_ec_reboot(struct cros_ec_dev *dev, enum ec_reboot_cmd cmd,
		uint8_t flags)
{
	struct ec_params_reboot_ec p;

	p.cmd = cmd;
	p.flags = flags;

	if (ec_command_inptr(dev, EC_CMD_REBOOT_EC, 0, &p, sizeof(p), NULL, 0)
			< 0)
		return -1;

	if (!(flags & EC_REBOOT_FLAG_ON_AP_SHUTDOWN)) {
		/*
		 * EC reboot will take place immediately so delay to allow it
		 * to complete.  Note that some reboot types (EC_REBOOT_COLD)
		 * will reboot the AP as well, in which case we won't actually
		 * get to this point.
		 */
		/*
		 * TODO(rspangler@chromium.org): Would be nice if we had a
		 * better way to determine when the reboot is complete.  Could
		 * we poll a memory-mapped LPC value?
		 */
		udelay(50000);
	}

	return 0;
}

int cros_ec_interrupt_pending(struct cros_ec_dev *dev)
{
	/* no interrupt support : always poll */
	if (!fdt_gpio_isvalid(&dev->ec_int))
		return 1;

	return !gpio_get_value(dev->ec_int.gpio);
}

int cros_ec_info(struct cros_ec_dev *dev, struct ec_response_cros_ec_info *info)
{
	if (ec_command(dev, EC_CMD_CROS_EC_INFO, 0, NULL, 0, info,
			sizeof(*info)) < sizeof(*info))
		return -1;

	return 0;
}

int cros_ec_get_host_events(struct cros_ec_dev *dev, uint32_t *events_ptr)
{
	struct ec_response_host_event_mask *resp;

	/*
	 * Use the B copy of the event flags, because the main copy is already
	 * used by ACPI/SMI.
	 */
	if (ec_command_inptr(dev, EC_CMD_HOST_EVENT_GET_B, 0, NULL, 0,
		       (uint8_t **)&resp, sizeof(*resp)) < sizeof(*resp))
		return -1;

	if (resp->mask & EC_HOST_EVENT_MASK(EC_HOST_EVENT_INVALID))
		return -1;

	*events_ptr = resp->mask;
	return 0;
}

int cros_ec_clear_host_events(struct cros_ec_dev *dev, uint32_t events)
{
	struct ec_params_host_event_mask params;

	params.mask = events;

	/*
	 * Use the B copy of the event flags, so it affects the data returned
	 * by cros_ec_get_host_events().
	 */
	if (ec_command_inptr(dev, EC_CMD_HOST_EVENT_CLEAR_B, 0,
		       &params, sizeof(params), NULL, 0) < 0)
		return -1;

	return 0;
}

int cros_ec_flash_protect(struct cros_ec_dev *dev,
		       uint32_t set_mask, uint32_t set_flags,
		       struct ec_response_flash_protect *resp)
{
	struct ec_params_flash_protect params;

	params.mask = set_mask;
	params.flags = set_flags;

	if (ec_command(dev, EC_CMD_FLASH_PROTECT, EC_VER_FLASH_PROTECT,
		       &params, sizeof(params),
		       resp, sizeof(*resp)) < sizeof(*resp))
		return -1;

	return 0;
}

static int cros_ec_check_version(struct cros_ec_dev *dev)
{
	struct ec_params_hello req;
	struct ec_response_hello *resp;

#ifdef CONFIG_CROS_EC_LPC
	/* LPC has its own way of doing this */
	if (dev->interface == CROS_EC_IF_LPC)
		return cros_ec_lpc_check_version(dev);
#endif

	/*
	 * TODO(sjg@chromium.org).
	 * There is a strange oddity here with the EC. We could just ignore
	 * the response, i.e. pass the last two parameters as NULL and 0.
	 * In this case we won't read back very many bytes from the EC.
	 * On the I2C bus the EC gets upset about this and will try to send
	 * the bytes anyway. This means that we will have to wait for that
	 * to complete before continuing with a new EC command.
	 *
	 * This problem is probably unique to the I2C bus.
	 *
	 * So for now, just read all the data anyway.
	 */
	dev->cmd_version_is_supported = 1;
	if (ec_command_inptr(dev, EC_CMD_HELLO, 0, &req, sizeof(req),
		       (uint8_t **)&resp, sizeof(*resp)) > 0) {
		/* It appears to understand new version commands */
		dev->cmd_version_is_supported = 1;
	} else {
		printf("%s: ERROR: old EC interface not supported\n",
		       __func__);
		return -1;
	}

	return 0;
}

int cros_ec_test(struct cros_ec_dev *dev)
{
	struct ec_params_hello req;
	struct ec_response_hello *resp;

	req.in_data = 0x12345678;
	if (ec_command_inptr(dev, EC_CMD_HELLO, 0, &req, sizeof(req),
		       (uint8_t **)&resp, sizeof(*resp)) < sizeof(*resp)) {
		printf("ec_command_inptr() returned error\n");
		return -1;
	}
	if (resp->out_data != req.in_data + 0x01020304) {
		printf("Received invalid handshake %x\n", resp->out_data);
		return -1;
	}

	return 0;
}

int cros_ec_flash_offset(struct cros_ec_dev *dev, enum ec_flash_region region,
		      uint32_t *offset, uint32_t *size)
{
	struct ec_params_flash_region_info p;
	struct ec_response_flash_region_info *r;
	int ret;

	p.region = region;
	ret = ec_command_inptr(dev, EC_CMD_FLASH_REGION_INFO,
			 EC_VER_FLASH_REGION_INFO,
			 &p, sizeof(p), (uint8_t **)&r, sizeof(*r));
	if (ret != sizeof(*r))
		return -1;

	if (offset)
		*offset = r->offset;
	if (size)
		*size = r->size;

	return 0;
}

int cros_ec_flash_erase(struct cros_ec_dev *dev, uint32_t offset, uint32_t size)
{
	struct ec_params_flash_erase p;

	p.offset = offset;
	p.size = size;
	return ec_command_inptr(dev, EC_CMD_FLASH_ERASE, 0, &p, sizeof(p),
			NULL, 0);
}

/**
 * Write a single block to the flash
 *
 * Write a block of data to the EC flash. The size must not exceed the flash
 * write block size which you can obtain from cros_ec_flash_write_burst_size().
 *
 * The offset starts at 0. You can obtain the region information from
 * cros_ec_flash_offset() to find out where to write for a particular region.
 *
 * Attempting to write to the region where the EC is currently running from
 * will result in an error.
 *
 * @param dev		CROS-EC device
 * @param data		Pointer to data buffer to write
 * @param offset	Offset within flash to write to.
 * @param size		Number of bytes to write
 * @return 0 if ok, -1 on error
 */
static int cros_ec_flash_write_block(struct cros_ec_dev *dev,
		const uint8_t *data, uint32_t offset, uint32_t size)
{
	struct ec_params_flash_write p;

	p.offset = offset;
	p.size = size;
	assert(data && p.size <= sizeof(p.data));
	memcpy(p.data, data, p.size);

	return ec_command_inptr(dev, EC_CMD_FLASH_WRITE, 0,
			  &p, sizeof(p), NULL, 0) >= 0 ? 0 : -1;
}

/**
 * Return optimal flash write burst size
 */
static int cros_ec_flash_write_burst_size(struct cros_ec_dev *dev)
{
	struct ec_params_flash_write p;
	return sizeof(p.data);
}

/**
 * Check if a block of data is erased (all 0xff)
 *
 * This function is useful when dealing with flash, for checking whether a
 * data block is erased and thus does not need to be programmed.
 *
 * @param data		Pointer to data to check (must be word-aligned)
 * @param size		Number of bytes to check (must be word-aligned)
 * @return 0 if erased, non-zero if any word is not erased
 */
static int cros_ec_data_is_erased(const uint32_t *data, int size)
{
	assert(!(size & 3));
	size /= sizeof(uint32_t);
	for (; size > 0; size -= 4, data++)
		if (*data != -1U)
			return 0;

	return 1;
}

int cros_ec_flash_write(struct cros_ec_dev *dev, const uint8_t *data,
		     uint32_t offset, uint32_t size)
{
	uint32_t burst = cros_ec_flash_write_burst_size(dev);
	uint32_t end, off;
	int ret;

	/*
	 * TODO: round up to the nearest multiple of write size.  Can get away
	 * without that on link right now because its write size is 4 bytes.
	 */
	end = offset + size;
	for (off = offset; off < end; off += burst, data += burst) {
		uint32_t todo;

		/* If the data is empty, there is no point in programming it */
		todo = min(end - off, burst);
		if (dev->optimise_flash_write &&
				cros_ec_data_is_erased((uint32_t *)data, todo))
			continue;

		ret = cros_ec_flash_write_block(dev, data, off, todo);
		if (ret)
			return ret;
	}

	return 0;
}

/**
 * Read a single block from the flash
 *
 * Read a block of data from the EC flash. The size must not exceed the flash
 * write block size which you can obtain from cros_ec_flash_write_burst_size().
 *
 * The offset starts at 0. You can obtain the region information from
 * cros_ec_flash_offset() to find out where to read for a particular region.
 *
 * @param dev		CROS-EC device
 * @param data		Pointer to data buffer to read into
 * @param offset	Offset within flash to read from
 * @param size		Number of bytes to read
 * @return 0 if ok, -1 on error
 */
static int cros_ec_flash_read_block(struct cros_ec_dev *dev, uint8_t *data,
				 uint32_t offset, uint32_t size)
{
	struct ec_params_flash_read p;

	p.offset = offset;
	p.size = size;

	return ec_command(dev, EC_CMD_FLASH_READ, 0,
			  &p, sizeof(p), data, size) >= 0 ? 0 : -1;
}

int cros_ec_flash_read(struct cros_ec_dev *dev, uint8_t *data, uint32_t offset,
		    uint32_t size)
{
	uint32_t burst = cros_ec_flash_write_burst_size(dev);
	uint32_t end, off;
	int ret;

	end = offset + size;
	for (off = offset; off < end; off += burst, data += burst) {
		ret = cros_ec_flash_read_block(dev, data, off,
					    min(end - off, burst));
		if (ret)
			return ret;
	}

	return 0;
}

int cros_ec_flash_update_rw(struct cros_ec_dev *dev,
			 const uint8_t *image, int image_size)
{
	uint32_t rw_offset, rw_size;
	int ret;

	if (cros_ec_flash_offset(dev, EC_FLASH_REGION_RW, &rw_offset, &rw_size))
		return -1;
	if (image_size > rw_size)
		return -1;

	/* Invalidate the existing hash, just in case the AP reboots
	 * unexpectedly during the update. If that happened, the EC RW firmware
	 * would be invalid, but the EC would still have the original hash.
	 */
	ret = cros_ec_invalidate_hash(dev);
	if (ret)
		return ret;

	/*
	 * Erase the entire RW section, so that the EC doesn't see any garbage
	 * past the new image if it's smaller than the current image.
	 *
	 * TODO: could optimize this to erase just the current image, since
	 * presumably everything past that is 0xff's.  But would still need to
	 * round up to the nearest multiple of erase size.
	 */
	ret = cros_ec_flash_erase(dev, rw_offset, rw_size);
	if (ret)
		return ret;

	/* Write the image */
	ret = cros_ec_flash_write(dev, image, rw_offset, image_size);
	if (ret)
		return ret;

	return 0;
}

int cros_ec_read_vbnvcontext(struct cros_ec_dev *dev, uint8_t *block)
{
	struct ec_params_vbnvcontext p;
	int len;

	p.op = EC_VBNV_CONTEXT_OP_READ;

	len = ec_command(dev, EC_CMD_VBNV_CONTEXT, EC_VER_VBNV_CONTEXT,
			&p, sizeof(p), block, EC_VBNV_BLOCK_SIZE);
	if (len < EC_VBNV_BLOCK_SIZE)
		return -1;

	return 0;
}

int cros_ec_write_vbnvcontext(struct cros_ec_dev *dev, const uint8_t *block)
{
	struct ec_params_vbnvcontext p;
	int len;

	p.op = EC_VBNV_CONTEXT_OP_WRITE;
	memcpy(p.block, block, sizeof(p.block));

	len = ec_command_inptr(dev, EC_CMD_VBNV_CONTEXT, EC_VER_VBNV_CONTEXT,
			&p, sizeof(p), NULL, 0);
	if (len < 0)
		return -1;

	return 0;
}

int cros_ec_set_ldo(struct cros_ec_dev *dev, uint8_t index, uint8_t state)
{
	struct ec_params_ldo_set params;

	params.index = index;
	params.state = state;

	if (ec_command_inptr(dev, EC_CMD_LDO_SET, 0,
		       &params, sizeof(params),
		       NULL, 0))
		return -1;

	return 0;
}

int cros_ec_get_ldo(struct cros_ec_dev *dev, uint8_t index, uint8_t *state)
{
	struct ec_params_ldo_get params;
	struct ec_response_ldo_get *resp;

	params.index = index;

	if (ec_command_inptr(dev, EC_CMD_LDO_GET, 0,
		       &params, sizeof(params),
		       (uint8_t **)&resp, sizeof(*resp)) < sizeof(*resp))
		return -1;

	*state = resp->state;

	return 0;
}

/**
 * Decode MBKP details from the device tree and allocate a suitable device.
 *
 * @param blob		Device tree blob
 * @param node		Node to decode from
 * @param devp		Returns a pointer to the new allocated device
 * @return 0 if ok, -1 on error
 */
static int cros_ec_decode_fdt(const void *blob, int node,
		struct cros_ec_dev **devp)
{
	enum fdt_compat_id compat;
	struct cros_ec_dev *dev;
	int parent;

	/* See what type of parent we are inside (this is expensive) */
	parent = fdt_parent_offset(blob, node);
	if (parent < 0) {
		debug("%s: Cannot find node parent\n", __func__);
		return -1;
	}

	dev = &static_dev;
	dev->node = node;
	dev->parent_node = parent;

	compat = fdtdec_lookup(blob, parent);
	switch (compat) {
#ifdef CONFIG_CROS_EC_SPI
	case COMPAT_SAMSUNG_EXYNOS_SPI:
		dev->interface = CROS_EC_IF_SPI;
		if (cros_ec_spi_decode_fdt(dev, blob))
			return -1;
		break;
#endif
#ifdef CONFIG_CROS_EC_I2C
	case COMPAT_SAMSUNG_S3C2440_I2C:
		dev->interface = CROS_EC_IF_I2C;
		if (cros_ec_i2c_decode_fdt(dev, blob))
			return -1;
		break;
#endif
#ifdef CONFIG_CROS_EC_LPC
	case COMPAT_INTEL_LPC:
		dev->interface = CROS_EC_IF_LPC;
		break;
#endif
	default:
		debug("%s: Unknown compat id %d\n", __func__, compat);
		return -1;
	}

	fdtdec_decode_gpio(blob, node, "ec-interrupt", &dev->ec_int);
	dev->optimise_flash_write = fdtdec_get_bool(blob, node,
						    "optimise-flash-write");
	*devp = dev;

	return 0;
}

int cros_ec_init(const void *blob, struct cros_ec_dev **cros_ecp)
{
	char id[MSG_BYTES];
	struct cros_ec_dev *dev;
	int node = 0;

	*cros_ecp = NULL;
	do {
		node = fdtdec_next_compatible(blob, node,
					      COMPAT_GOOGLE_CROS_EC);
		if (node < 0) {
			debug("%s: Node not found\n", __func__);
			return 0;
		}
	} while (!fdtdec_get_is_enabled(blob, node));

	if (cros_ec_decode_fdt(blob, node, &dev)) {
		debug("%s: Failed to decode device.\n", __func__);
		return -CROS_EC_ERR_FDT_DECODE;
	}

	switch (dev->interface) {
#ifdef CONFIG_CROS_EC_SPI
	case CROS_EC_IF_SPI:
		if (cros_ec_spi_init(dev, blob)) {
			debug("%s: Could not setup SPI interface\n", __func__);
			return -CROS_EC_ERR_DEV_INIT;
		}
		break;
#endif
#ifdef CONFIG_CROS_EC_I2C
	case CROS_EC_IF_I2C:
		if (cros_ec_i2c_init(dev, blob))
			return -CROS_EC_ERR_DEV_INIT;
		break;
#endif
#ifdef CONFIG_CROS_EC_LPC
	case CROS_EC_IF_LPC:
		if (cros_ec_lpc_init(dev, blob))
			return -CROS_EC_ERR_DEV_INIT;
		break;
#endif
	case CROS_EC_IF_NONE:
	default:
		return 0;
	}

	/* we will poll the EC interrupt line */
	fdtdec_setup_gpio(&dev->ec_int);
	if (fdt_gpio_isvalid(&dev->ec_int))
		gpio_direction_input(dev->ec_int.gpio);

	if (cros_ec_check_version(dev)) {
		debug("%s: Could not detect CROS-EC version\n", __func__);
		return -CROS_EC_ERR_CHECK_VERSION;
	}

	if (cros_ec_read_id(dev, id, sizeof(id))) {
		debug("%s: Could not read KBC ID\n", __func__);
		return -CROS_EC_ERR_READ_ID;
	}

	/* Remember this device for use by the cros_ec command */
	last_dev = *cros_ecp = dev;
	debug("Google Chrome EC CROS-EC driver ready, id '%s'\n", id);

	return 0;
}

#ifdef CONFIG_CMD_CROS_EC
int cros_ec_decode_region(int argc, char * const argv[])
{
	if (argc > 0) {
		if (0 == strcmp(*argv, "rw"))
			return EC_FLASH_REGION_RW;
		else if (0 == strcmp(*argv, "ro"))
			return EC_FLASH_REGION_RO;

		debug("%s: Invalid region '%s'\n", __func__, *argv);
	} else {
		debug("%s: Missing region parameter\n", __func__);
	}

	return -1;
}

int cros_ec_decode_ec_flash(const void *blob, struct fdt_cros_ec *config)
{
	int flash_node, node;

	node = fdtdec_next_compatible(blob, 0, COMPAT_GOOGLE_CROS_EC);
	if (node < 0) {
		debug("Failed to find chrome-ec node'\n");
		return -1;
	}

	flash_node = fdt_subnode_offset(blob, node, "flash");
	if (flash_node < 0) {
		debug("Failed to find flash node\n");
		return -1;
	}

	if (fdtdec_read_fmap_entry(blob, flash_node, "flash",
				   &config->flash)) {
		debug("Failed to decode flash node in chrome-ec'\n");
		return -1;
	}

	config->flash_erase_value = fdtdec_get_int(blob, flash_node,
						    "erase-value", -1);
	for (node = fdt_first_subnode(blob, flash_node); node >= 0;
	     node = fdt_next_subnode(blob, node)) {
		const char *name = fdt_get_name(blob, node, NULL);
		enum ec_flash_region region;

		if (0 == strcmp(name, "ro")) {
			region = EC_FLASH_REGION_RO;
		} else if (0 == strcmp(name, "rw")) {
			region = EC_FLASH_REGION_RW;
		} else if (0 == strcmp(name, "wp-ro")) {
			region = EC_FLASH_REGION_WP_RO;
		} else {
			debug("Unknown EC flash region name '%s'\n", name);
			return -1;
		}

		if (fdtdec_read_fmap_entry(blob, node, "reg",
					   &config->region[region])) {
			debug("Failed to decode flash region in chrome-ec'\n");
			return -1;
		}
	}

	return 0;
}