cros: add cros_ec driver

This patch adds the cros_ec driver that implements the protocol for
communicating with Google's ChromeOS embedded controller.

Signed-off-by: Bernie Thompson <bhthompson@chromium.org>
Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Signed-off-by: Che-Liang Chiou <clchiou@chromium.org>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Gabe Black <gabeblack@chromium.org>
Signed-off-by: Hung-ying Tyan <tyanh@chromium.org>
Signed-off-by: Louis Yung-Chieh Lo <yjlou@chromium.org>
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>

1 files changed, 1304 insertions, 0 deletions

diff --git a/drivers/misc/cros_ec.c b/drivers/misc/cros_ec.c
new file mode 100644
index 000000000..6e774d921
--- /dev/null
+++ b/drivers/misc/cros_ec.c
@@ -0,0 +1,1304 @@
+/*
+ * Chromium OS cros_ec driver
+ *
+ * Copyright (c) 2012 The Chromium OS Authors.
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+/*
+ * 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;
+
+	if (cmd_version != 0 && !dev->cmd_version_is_supported) {
+		debug("%s: Command version >0 unsupported\n", __func__);
+		return -1;
+	}
+	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 {
+		dev->cmd_version_is_supported = 0;
+		if (ec_command_inptr(dev, EC_CMD_HELLO, 0, &req,
+			      sizeof(req), (uint8_t **)&resp,
+			      sizeof(*resp)) < 0) {
+			debug("%s: Failed both old and new command style\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;
+}
+
+/**
+ * Perform a flash read or write command
+ *
+ * @param dev		CROS-EC device to read/write
+ * @param is_write	1 do to a write, 0 to do a read
+ * @param argc		Number of arguments
+ * @param argv		Arguments (2 is region, 3 is address)
+ * @return 0 for ok, 1 for a usage error or -ve for ec command error
+ *	(negative EC_RES_...)
+ */
+static int do_read_write(struct cros_ec_dev *dev, int is_write, int argc,
+			 char * const argv[])
+{
+	uint32_t offset, size = -1U, region_size;
+	unsigned long addr;
+	char *endp;
+	int region;
+	int ret;
+
+	region = cros_ec_decode_region(argc - 2, argv + 2);
+	if (region == -1)
+		return 1;
+	if (argc < 4)
+		return 1;
+	addr = simple_strtoul(argv[3], &endp, 16);
+	if (*argv[3] == 0 || *endp != 0)
+		return 1;
+	if (argc > 4) {
+		size = simple_strtoul(argv[4], &endp, 16);
+		if (*argv[4] == 0 || *endp != 0)
+			return 1;
+	}
+
+	ret = cros_ec_flash_offset(dev, region, &offset, &region_size);
+	if (ret) {
+		debug("%s: Could not read region info\n", __func__);
+		return ret;
+	}
+	if (size == -1U)
+		size = region_size;
+
+	ret = is_write ?
+		cros_ec_flash_write(dev, (uint8_t *)addr, offset, size) :
+		cros_ec_flash_read(dev, (uint8_t *)addr, offset, size);
+	if (ret) {
+		debug("%s: Could not %s region\n", __func__,
+		      is_write ? "write" : "read");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int do_cros_ec(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	struct cros_ec_dev *dev = last_dev;
+	const char *cmd;
+	int ret = 0;
+
+	if (argc < 2)
+		return CMD_RET_USAGE;
+
+	cmd = argv[1];
+	if (0 == strcmp("init", cmd)) {
+		ret = cros_ec_init(gd->fdt_blob, &dev);
+		if (ret) {
+			printf("Could not init cros_ec device (err %d)\n", ret);
+			return 1;
+		}
+		return 0;
+	}
+
+	/* Just use the last allocated device; there should be only one */
+	if (!last_dev) {
+		printf("No CROS-EC device available\n");
+		return 1;
+	}
+	if (0 == strcmp("id", cmd)) {
+		char id[MSG_BYTES];
+
+		if (cros_ec_read_id(dev, id, sizeof(id))) {
+			debug("%s: Could not read KBC ID\n", __func__);
+			return 1;
+		}
+		printf("%s\n", id);
+	} else if (0 == strcmp("info", cmd)) {
+		struct ec_response_cros_ec_info info;
+
+		if (cros_ec_info(dev, &info)) {
+			debug("%s: Could not read KBC info\n", __func__);
+			return 1;
+		}
+		printf("rows     = %u\n", info.rows);
+		printf("cols     = %u\n", info.cols);
+		printf("switches = %#x\n", info.switches);
+	} else if (0 == strcmp("curimage", cmd)) {
+		enum ec_current_image image;
+
+		if (cros_ec_read_current_image(dev, &image)) {
+			debug("%s: Could not read KBC image\n", __func__);
+			return 1;
+		}
+		printf("%d\n", image);
+	} else if (0 == strcmp("hash", cmd)) {
+		struct ec_response_vboot_hash hash;
+		int i;
+
+		if (cros_ec_read_hash(dev, &hash)) {
+			debug("%s: Could not read KBC hash\n", __func__);
+			return 1;
+		}
+
+		if (hash.hash_type == EC_VBOOT_HASH_TYPE_SHA256)
+			printf("type:    SHA-256\n");
+		else
+			printf("type:    %d\n", hash.hash_type);
+
+		printf("offset:  0x%08x\n", hash.offset);
+		printf("size:    0x%08x\n", hash.size);
+
+		printf("digest:  ");
+		for (i = 0; i < hash.digest_size; i++)
+			printf("%02x", hash.hash_digest[i]);
+		printf("\n");
+	} else if (0 == strcmp("reboot", cmd)) {
+		int region;
+		enum ec_reboot_cmd cmd;
+
+		if (argc >= 3 && !strcmp(argv[2], "cold"))
+			cmd = EC_REBOOT_COLD;
+		else {
+			region = cros_ec_decode_region(argc - 2, argv + 2);
+			if (region == EC_FLASH_REGION_RO)
+				cmd = EC_REBOOT_JUMP_RO;
+			else if (region == EC_FLASH_REGION_RW)
+				cmd = EC_REBOOT_JUMP_RW;
+			else
+				return CMD_RET_USAGE;
+		}
+
+		if (cros_ec_reboot(dev, cmd, 0)) {
+			debug("%s: Could not reboot KBC\n", __func__);
+			return 1;
+		}
+	} else if (0 == strcmp("events", cmd)) {
+		uint32_t events;
+
+		if (cros_ec_get_host_events(dev, &events)) {
+			debug("%s: Could not read host events\n", __func__);
+			return 1;
+		}
+		printf("0x%08x\n", events);
+	} else if (0 == strcmp("clrevents", cmd)) {
+		uint32_t events = 0x7fffffff;
+
+		if (argc >= 3)
+			events = simple_strtol(argv[2], NULL, 0);
+
+		if (cros_ec_clear_host_events(dev, events)) {
+			debug("%s: Could not clear host events\n", __func__);
+			return 1;
+		}
+	} else if (0 == strcmp("read", cmd)) {
+		ret = do_read_write(dev, 0, argc, argv);
+		if (ret > 0)
+			return CMD_RET_USAGE;
+	} else if (0 == strcmp("write", cmd)) {
+		ret = do_read_write(dev, 1, argc, argv);
+		if (ret > 0)
+			return CMD_RET_USAGE;
+	} else if (0 == strcmp("erase", cmd)) {
+		int region = cros_ec_decode_region(argc - 2, argv + 2);
+		uint32_t offset, size;
+
+		if (region == -1)
+			return CMD_RET_USAGE;
+		if (cros_ec_flash_offset(dev, region, &offset, &size)) {
+			debug("%s: Could not read region info\n", __func__);
+			ret = -1;
+		} else {
+			ret = cros_ec_flash_erase(dev, offset, size);
+			if (ret) {
+				debug("%s: Could not erase region\n",
+				      __func__);
+			}
+		}
+	} else if (0 == strcmp("regioninfo", cmd)) {
+		int region = cros_ec_decode_region(argc - 2, argv + 2);
+		uint32_t offset, size;
+
+		if (region == -1)
+			return CMD_RET_USAGE;
+		ret = cros_ec_flash_offset(dev, region, &offset, &size);
+		if (ret) {
+			debug("%s: Could not read region info\n", __func__);
+		} else {
+			printf("Region: %s\n", region == EC_FLASH_REGION_RO ?
+					"RO" : "RW");
+			printf("Offset: %x\n", offset);
+			printf("Size:   %x\n", size);
+		}
+	} else if (0 == strcmp("vbnvcontext", cmd)) {
+		uint8_t block[EC_VBNV_BLOCK_SIZE];
+		char buf[3];
+		int i, len;
+		unsigned long result;
+
+		if (argc <= 2) {
+			ret = cros_ec_read_vbnvcontext(dev, block);
+			if (!ret) {
+				printf("vbnv_block: ");
+				for (i = 0; i < EC_VBNV_BLOCK_SIZE; i++)
+					printf("%02x", block[i]);
+				putc('\n');
+			}
+		} else {
+			/*
+			 * TODO(clchiou): Move this to a utility function as
+			 * cmd_spi might want to call it.
+			 */
+			memset(block, 0, EC_VBNV_BLOCK_SIZE);
+			len = strlen(argv[2]);
+			buf[2] = '\0';
+			for (i = 0; i < EC_VBNV_BLOCK_SIZE; i++) {
+				if (i * 2 >= len)
+					break;
+				buf[0] = argv[2][i * 2];
+				if (i * 2 + 1 >= len)
+					buf[1] = '0';
+				else
+					buf[1] = argv[2][i * 2 + 1];
+				strict_strtoul(buf, 16, &result);
+				block[i] = result;
+			}
+			ret = cros_ec_write_vbnvcontext(dev, block);
+		}
+		if (ret) {
+			debug("%s: Could not %s VbNvContext\n", __func__,
+					argc <= 2 ?  "read" : "write");
+		}
+	} else if (0 == strcmp("test", cmd)) {
+		int result = cros_ec_test(dev);
+
+		if (result)
+			printf("Test failed with error %d\n", result);
+		else
+			puts("Test passed\n");
+	} else if (0 == strcmp("version", cmd)) {
+		struct ec_response_get_version *p;
+		char *build_string;
+
+		ret = cros_ec_read_version(dev, &p);
+		if (!ret) {
+			/* Print versions */
+			printf("RO version:    %1.*s\n",
+			       sizeof(p->version_string_ro),
+			       p->version_string_ro);
+			printf("RW version:    %1.*s\n",
+			       sizeof(p->version_string_rw),
+			       p->version_string_rw);
+			printf("Firmware copy: %s\n",
+				(p->current_image <
+					ARRAY_SIZE(ec_current_image_name) ?
+				ec_current_image_name[p->current_image] :
+				"?"));
+			ret = cros_ec_read_build_info(dev, &build_string);
+			if (!ret)
+				printf("Build info:    %s\n", build_string);
+		}
+	} else if (0 == strcmp("ldo", cmd)) {
+		uint8_t index, state;
+		char *endp;
+
+		if (argc < 3)
+			return CMD_RET_USAGE;
+		index = simple_strtoul(argv[2], &endp, 10);
+		if (*argv[2] == 0 || *endp != 0)
+			return CMD_RET_USAGE;
+		if (argc > 3) {
+			state = simple_strtoul(argv[3], &endp, 10);
+			if (*argv[3] == 0 || *endp != 0)
+				return CMD_RET_USAGE;
+			ret = cros_ec_set_ldo(dev, index, state);
+		} else {
+			ret = cros_ec_get_ldo(dev, index, &state);
+			if (!ret) {
+				printf("LDO%d: %s\n", index,
+					state == EC_LDO_STATE_ON ?
+					"on" : "off");
+			}
+		}
+
+		if (ret) {
+			debug("%s: Could not access LDO%d\n", __func__, index);
+			return ret;
+		}
+	} else {
+		return CMD_RET_USAGE;
+	}
+
+	if (ret < 0) {
+		printf("Error: CROS-EC command failed (error %d)\n", ret);
+		ret = 1;
+	}
+
+	return ret;
+}
+
+U_BOOT_CMD(
+	crosec,	5,	1,	do_cros_ec,
+	"CROS-EC utility command",
+	"init                Re-init CROS-EC (done on startup automatically)\n"
+	"crosec id                  Read CROS-EC ID\n"
+	"crosec info                Read CROS-EC info\n"
+	"crosec curimage            Read CROS-EC current image\n"
+	"crosec hash                Read CROS-EC hash\n"
+	"crosec reboot [rw | ro | cold]  Reboot CROS-EC\n"
+	"crosec events              Read CROS-EC host events\n"
+	"crosec clrevents [mask]    Clear CROS-EC host events\n"
+	"crosec regioninfo <ro|rw>  Read image info\n"
+	"crosec erase <ro|rw>       Erase EC image\n"
+	"crosec read <ro|rw> <addr> [<size>]   Read EC image\n"
+	"crosec write <ro|rw> <addr> [<size>]  Write EC image\n"
+	"crosec vbnvcontext [hexstring]        Read [write] VbNvContext from EC\n"
+	"crosec ldo <idx> [<state>] Switch/Read LDO state\n"
+	"crosec test                run tests on cros_ec\n"
+	"crosec version             Read CROS-EC version"
+);
+#endif