// SPDX-License-Identifier: GPL-2.0
// ChromeOS EC communication protocol helper functions
//
// Copyright (C) 2015 Google, Inc

#include <linux/cleanup.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/limits.h>
#include <linux/module.h>
#include <linux/platform_data/cros_ec_commands.h>
#include <linux/platform_data/cros_ec_proto.h>
#include <linux/slab.h>
#include <linux/unaligned.h>

#include "cros_ec_trace.h"

#define EC_COMMAND_RETRIES      50
#define RWSIG_CONTINUE_RETRIES  8
#define RWSIG_CONTINUE_MAX_ERRORS_IN_ROW        3

static const int cros_ec_error_map[] = {
        [EC_RES_INVALID_COMMAND] = -EOPNOTSUPP,
        [EC_RES_ERROR] = -EIO,
        [EC_RES_INVALID_PARAM] = -EINVAL,
        [EC_RES_ACCESS_DENIED] = -EACCES,
        [EC_RES_INVALID_RESPONSE] = -EPROTO,
        [EC_RES_INVALID_VERSION] = -ENOPROTOOPT,
        [EC_RES_INVALID_CHECKSUM] = -EBADMSG,
        [EC_RES_IN_PROGRESS] = -EINPROGRESS,
        [EC_RES_UNAVAILABLE] = -ENODATA,
        [EC_RES_TIMEOUT] = -ETIMEDOUT,
        [EC_RES_OVERFLOW] = -EOVERFLOW,
        [EC_RES_INVALID_HEADER] = -EBADR,
        [EC_RES_REQUEST_TRUNCATED] = -EBADR,
        [EC_RES_RESPONSE_TOO_BIG] = -EFBIG,
        [EC_RES_BUS_ERROR] = -EFAULT,
        [EC_RES_BUSY] = -EBUSY,
        [EC_RES_INVALID_HEADER_VERSION] = -EBADMSG,
        [EC_RES_INVALID_HEADER_CRC] = -EBADMSG,
        [EC_RES_INVALID_DATA_CRC] = -EBADMSG,
        [EC_RES_DUP_UNAVAILABLE] = -ENODATA,
};

static int cros_ec_map_error(uint32_t result)
{
        int ret = 0;

        if (result != EC_RES_SUCCESS) {
                if (result < ARRAY_SIZE(cros_ec_error_map) && cros_ec_error_map[result])
                        ret = cros_ec_error_map[result];
                else
                        ret = -EPROTO;
        }

        return ret;
}

static int prepare_tx(struct cros_ec_device *ec_dev,
                      struct cros_ec_command *msg)
{
        struct ec_host_request *request;
        u8 *out;
        int i;
        u8 csum = 0;

        if (msg->outsize + sizeof(*request) > ec_dev->dout_size)
                return -EINVAL;

        out = ec_dev->dout;
        request = (struct ec_host_request *)out;
        request->struct_version = EC_HOST_REQUEST_VERSION;
        request->checksum = 0;
        request->command = msg->command;
        request->command_version = msg->version;
        request->reserved = 0;
        request->data_len = msg->outsize;

        for (i = 0; i < sizeof(*request); i++)
                csum += out[i];

        /* Copy data and update checksum */
        memcpy(out + sizeof(*request), msg->data, msg->outsize);
        for (i = 0; i < msg->outsize; i++)
                csum += msg->data[i];

        request->checksum = -csum;

        return sizeof(*request) + msg->outsize;
}

static int prepare_tx_legacy(struct cros_ec_device *ec_dev,
                             struct cros_ec_command *msg)
{
        u8 *out;
        u8 csum;
        int i;

        if (msg->outsize > EC_PROTO2_MAX_PARAM_SIZE)
                return -EINVAL;

        out = ec_dev->dout;
        out[0] = EC_CMD_VERSION0 + msg->version;
        out[1] = msg->command;
        out[2] = msg->outsize;
        csum = out[0] + out[1] + out[2];
        for (i = 0; i < msg->outsize; i++)
                csum += out[EC_MSG_TX_HEADER_BYTES + i] = msg->data[i];
        out[EC_MSG_TX_HEADER_BYTES + msg->outsize] = csum;

        return EC_MSG_TX_PROTO_BYTES + msg->outsize;
}

static int cros_ec_xfer_command(struct cros_ec_device *ec_dev, struct cros_ec_command *msg)
{
        int ret;
        int (*xfer_fxn)(struct cros_ec_device *ec, struct cros_ec_command *msg);

        if (ec_dev->proto_version > 2)
                xfer_fxn = ec_dev->pkt_xfer;
        else
                xfer_fxn = ec_dev->cmd_xfer;

        if (!xfer_fxn) {
                /*
                 * This error can happen if a communication error happened and
                 * the EC is trying to use protocol v2, on an underlying
                 * communication mechanism that does not support v2.
                 */
                dev_err_once(ec_dev->dev, "missing EC transfer API, cannot send command\n");
                return -EIO;
        }

        trace_cros_ec_request_start(msg);
        ret = (*xfer_fxn)(ec_dev, msg);
        trace_cros_ec_request_done(msg, ret);

        return ret;
}

static int cros_ec_wait_until_complete(struct cros_ec_device *ec_dev, uint32_t *result)
{
        DEFINE_RAW_FLEX(struct cros_ec_command, msg, data,
                        sizeof(struct ec_response_get_comms_status));
        struct ec_response_get_comms_status *status =
                        (struct ec_response_get_comms_status *)msg->data;
        int ret = 0, i;

        msg->version = 0;
        msg->command = EC_CMD_GET_COMMS_STATUS;
        msg->insize = sizeof(*status);
        msg->outsize = 0;

        /* Query the EC's status until it's no longer busy or we encounter an error. */
        for (i = 0; i < EC_COMMAND_RETRIES; ++i) {
                usleep_range(10000, 11000);

                ret = cros_ec_xfer_command(ec_dev, msg);
                if (ret == -EAGAIN)
                        continue;
                if (ret < 0)
                        return ret;

                *result = msg->result;
                if (msg->result != EC_RES_SUCCESS)
                        return ret;

                if (ret == 0) {
                        ret = -EPROTO;
                        break;
                }

                if (!(status->flags & EC_COMMS_STATUS_PROCESSING))
                        return ret;
        }

        if (i >= EC_COMMAND_RETRIES)
                ret = -EAGAIN;

        return ret;
}

static int cros_ec_send_command(struct cros_ec_device *ec_dev, struct cros_ec_command *msg)
{
        int ret = cros_ec_xfer_command(ec_dev, msg);

        if (msg->result == EC_RES_IN_PROGRESS)
                ret = cros_ec_wait_until_complete(ec_dev, &msg->result);

        return ret;
}

/**
 * cros_ec_prepare_tx() - Prepare an outgoing message in the output buffer.
 * @ec_dev: Device to register.
 * @msg: Message to write.
 *
 * This is used by all ChromeOS EC drivers to prepare the outgoing message
 * according to different protocol versions.
 *
 * Return: number of prepared bytes on success or negative error code.
 */
int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
                       struct cros_ec_command *msg)
{
        if (ec_dev->proto_version > 2)
                return prepare_tx(ec_dev, msg);

        return prepare_tx_legacy(ec_dev, msg);
}
EXPORT_SYMBOL(cros_ec_prepare_tx);

/**
 * cros_ec_check_result() - Check ec_msg->result.
 * @ec_dev: EC device.
 * @msg: Message to check.
 *
 * This is used by ChromeOS EC drivers to check the ec_msg->result for
 * EC_RES_IN_PROGRESS and to warn about them.
 *
 * The function should not check for furthermore error codes.  Otherwise,
 * it would break the ABI.
 *
 * Return: -EAGAIN if ec_msg->result == EC_RES_IN_PROGRESS.  Otherwise, 0.
 */
int cros_ec_check_result(struct cros_ec_device *ec_dev,
                         struct cros_ec_command *msg)
{
        switch (msg->result) {
        case EC_RES_SUCCESS:
                return 0;
        case EC_RES_IN_PROGRESS:
                dev_dbg(ec_dev->dev, "command 0x%02x in progress\n",
                        msg->command);
                return -EAGAIN;
        default:
                dev_dbg(ec_dev->dev, "command 0x%02x returned %d\n",
                        msg->command, msg->result);
                return 0;
        }
}
EXPORT_SYMBOL(cros_ec_check_result);

/**
 * cros_ec_get_host_event_wake_mask
 *
 * Get the mask of host events that cause wake from suspend.
 *
 * @ec_dev: EC device to call
 * @mask: result when function returns 0.
 *
 * LOCKING:
 * the caller has ec_dev->lock mutex, or the caller knows there is
 * no other command in progress.
 */
static int cros_ec_get_host_event_wake_mask(struct cros_ec_device *ec_dev, uint32_t *mask)
{
        struct cros_ec_command *msg;
        struct ec_response_host_event_mask *r;
        int ret, mapped;

        msg = kzalloc(sizeof(*msg) + sizeof(*r), GFP_KERNEL);
        if (!msg)
                return -ENOMEM;

        msg->command = EC_CMD_HOST_EVENT_GET_WAKE_MASK;
        msg->insize = sizeof(*r);

        ret = cros_ec_send_command(ec_dev, msg);
        if (ret < 0)
                goto exit;

        mapped = cros_ec_map_error(msg->result);
        if (mapped) {
                ret = mapped;
                goto exit;
        }

        if (ret == 0) {
                ret = -EPROTO;
                goto exit;
        }

        r = (struct ec_response_host_event_mask *)msg->data;
        *mask = r->mask;
        ret = 0;
exit:
        kfree(msg);
        return ret;
}

int cros_ec_rwsig_continue(struct cros_ec_device *ec_dev)
{
        struct cros_ec_command *msg;
        struct ec_params_rwsig_action *rwsig_action;
        int ret = 0;
        int error_count = 0;

        ec_dev->proto_version = 3;

        msg = kmalloc(sizeof(*msg) + sizeof(*rwsig_action), GFP_KERNEL);
        if (!msg)
                return -ENOMEM;

        msg->version = 0;
        msg->command = EC_CMD_RWSIG_ACTION;
        msg->insize = 0;
        msg->outsize = sizeof(*rwsig_action);

        rwsig_action = (struct ec_params_rwsig_action *)msg->data;
        rwsig_action->action = RWSIG_ACTION_CONTINUE;

        for (int i = 0; i < RWSIG_CONTINUE_RETRIES; i++) {
                ret = cros_ec_send_command(ec_dev, msg);

                if (ret < 0) {
                        if (++error_count >= RWSIG_CONTINUE_MAX_ERRORS_IN_ROW)
                                break;
                } else if (msg->result == EC_RES_INVALID_COMMAND) {
                        /*
                         * If EC_RES_INVALID_COMMAND is retured, it means RWSIG
                         * is not supported or EC is already in RW, so there is
                         * nothing left to do.
                         */
                        break;
                } else if (msg->result != EC_RES_SUCCESS) {
                        /* Unexpected command error. */
                        ret = cros_ec_map_error(msg->result);
                        break;
                } else {
                        /*
                         * The EC_CMD_RWSIG_ACTION succeed. Send the command
                         * more times, to make sure EC is in RW. A following
                         * command can timeout, because EC may need some time to
                         * initialize after jump to RW.
                         */
                        error_count = 0;
                }

                if (ret != -ETIMEDOUT)
                        usleep_range(90000, 100000);
        }

        kfree(msg);

        return ret;
}
EXPORT_SYMBOL(cros_ec_rwsig_continue);

static int cros_ec_get_proto_info(struct cros_ec_device *ec_dev, int devidx)
{
        struct cros_ec_command *msg;
        struct ec_response_get_protocol_info *info;
        int ret, mapped;

        ec_dev->proto_version = 3;
        if (devidx > 0)
                ec_dev->max_passthru = 0;

        msg = kzalloc(sizeof(*msg) + sizeof(*info), GFP_KERNEL);
        if (!msg)
                return -ENOMEM;

        msg->command = EC_CMD_PASSTHRU_OFFSET(devidx) | EC_CMD_GET_PROTOCOL_INFO;
        msg->insize = sizeof(*info);

        ret = cros_ec_send_command(ec_dev, msg);

        if (ret < 0) {
                dev_dbg(ec_dev->dev,
                        "failed to check for EC[%d] protocol version: %d\n",
                        devidx, ret);
                goto exit;
        }

        mapped = cros_ec_map_error(msg->result);
        if (mapped) {
                ret = mapped;
                goto exit;
        }

        if (ret == 0) {
                ret = -EPROTO;
                goto exit;
        }

        info = (struct ec_response_get_protocol_info *)msg->data;

        switch (devidx) {
        case CROS_EC_DEV_EC_INDEX:
                ec_dev->max_request = info->max_request_packet_size -
                                                sizeof(struct ec_host_request);
                ec_dev->max_response = info->max_response_packet_size -
                                                sizeof(struct ec_host_response);
                ec_dev->proto_version = min(EC_HOST_REQUEST_VERSION,
                                            fls(info->protocol_versions) - 1);
                ec_dev->din_size = info->max_response_packet_size + EC_MAX_RESPONSE_OVERHEAD;
                ec_dev->dout_size = info->max_request_packet_size + EC_MAX_REQUEST_OVERHEAD;

                dev_dbg(ec_dev->dev, "using proto v%u\n", ec_dev->proto_version);
                break;
        case CROS_EC_DEV_PD_INDEX:
                ec_dev->max_passthru = info->max_request_packet_size -
                                                sizeof(struct ec_host_request);

                dev_dbg(ec_dev->dev, "found PD chip\n");
                break;
        default:
                dev_dbg(ec_dev->dev, "unknown passthru index: %d\n", devidx);
                break;
        }

        ret = 0;
exit:
        kfree(msg);
        return ret;
}

static int cros_ec_get_proto_info_legacy(struct cros_ec_device *ec_dev)
{
        struct cros_ec_command *msg;
        struct ec_params_hello *params;
        struct ec_response_hello *response;
        int ret, mapped;

        ec_dev->proto_version = 2;

        msg = kzalloc(sizeof(*msg) + max(sizeof(*params), sizeof(*response)), GFP_KERNEL);
        if (!msg)
                return -ENOMEM;

        msg->command = EC_CMD_HELLO;
        msg->insize = sizeof(*response);
        msg->outsize = sizeof(*params);

        params = (struct ec_params_hello *)msg->data;
        params->in_data = 0xa0b0c0d0;

        ret = cros_ec_send_command(ec_dev, msg);
        if (ret < 0) {
                dev_dbg(ec_dev->dev, "EC failed to respond to v2 hello: %d\n", ret);
                goto exit;
        }

        mapped = cros_ec_map_error(msg->result);
        if (mapped) {
                ret = mapped;
                dev_err(ec_dev->dev, "EC responded to v2 hello with error: %d\n", msg->result);
                goto exit;
        }

        if (ret == 0) {
                ret = -EPROTO;
                goto exit;
        }

        response = (struct ec_response_hello *)msg->data;
        if (response->out_data != 0xa1b2c3d4) {
                dev_err(ec_dev->dev,
                        "EC responded to v2 hello with bad result: %u\n",
                        response->out_data);
                ret = -EBADMSG;
                goto exit;
        }

        ec_dev->max_request = EC_PROTO2_MAX_PARAM_SIZE;
        ec_dev->max_response = EC_PROTO2_MAX_PARAM_SIZE;
        ec_dev->max_passthru = 0;
        ec_dev->pkt_xfer = NULL;
        ec_dev->din_size = EC_PROTO2_MSG_BYTES;
        ec_dev->dout_size = EC_PROTO2_MSG_BYTES;

        dev_dbg(ec_dev->dev, "falling back to proto v2\n");
        ret = 0;
exit:
        kfree(msg);
        return ret;
}

/**
 * cros_ec_get_host_command_version_mask
 *
 * Get the version mask of a given command.
 *
 * @ec_dev: EC device to call
 * @cmd: command to get the version of.
 * @mask: result when function returns 0.
 *
 * @return 0 on success, error code otherwise
 *
 * LOCKING:
 * the caller has ec_dev->lock mutex or the caller knows there is
 * no other command in progress.
 */
static int cros_ec_get_host_command_version_mask(struct cros_ec_device *ec_dev, u16 cmd, u32 *mask)
{
        struct ec_params_get_cmd_versions *pver;
        struct ec_response_get_cmd_versions *rver;
        struct cros_ec_command *msg;
        int ret, mapped;

        msg = kmalloc(sizeof(*msg) + max(sizeof(*rver), sizeof(*pver)),
                      GFP_KERNEL);
        if (!msg)
                return -ENOMEM;

        msg->version = 0;
        msg->command = EC_CMD_GET_CMD_VERSIONS;
        msg->insize = sizeof(*rver);
        msg->outsize = sizeof(*pver);

        pver = (struct ec_params_get_cmd_versions *)msg->data;
        pver->cmd = cmd;

        ret = cros_ec_send_command(ec_dev, msg);
        if (ret < 0)
                goto exit;

        mapped = cros_ec_map_error(msg->result);
        if (mapped) {
                ret = mapped;
                goto exit;
        }

        if (ret == 0) {
                ret = -EPROTO;
                goto exit;
        }

        rver = (struct ec_response_get_cmd_versions *)msg->data;
        *mask = rver->version_mask;
        ret = 0;
exit:
        kfree(msg);
        return ret;
}

/**
 * cros_ec_query_all() -  Query the protocol version supported by the
 *         ChromeOS EC.
 * @ec_dev: Device to register.
 *
 * Return: 0 on success or negative error code.
 */
int cros_ec_query_all(struct cros_ec_device *ec_dev)
{
        struct device *dev = ec_dev->dev;
        u32 ver_mask;
        int ret;

        /* First try sending with proto v3. */
        if (!cros_ec_get_proto_info(ec_dev, CROS_EC_DEV_EC_INDEX)) {
                /* Check for PD. */
                cros_ec_get_proto_info(ec_dev, CROS_EC_DEV_PD_INDEX);
        } else {
                /* Try querying with a v2 hello message. */
                ret = cros_ec_get_proto_info_legacy(ec_dev);
                if (ret) {
                        /*
                         * It's possible for a test to occur too early when
                         * the EC isn't listening. If this happens, we'll
                         * test later when the first command is run.
                         */
                        ec_dev->proto_version = EC_PROTO_VERSION_UNKNOWN;
                        dev_dbg(ec_dev->dev, "EC query failed: %d\n", ret);
                        return ret;
                }
        }

        devm_kfree(dev, ec_dev->din);
        devm_kfree(dev, ec_dev->dout);

        ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
        if (!ec_dev->din) {
                ret = -ENOMEM;
                goto exit;
        }

        ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL);
        if (!ec_dev->dout) {
                devm_kfree(dev, ec_dev->din);
                ret = -ENOMEM;
                goto exit;
        }

        /* Probe if MKBP event is supported */
        ret = cros_ec_get_host_command_version_mask(ec_dev, EC_CMD_GET_NEXT_EVENT, &ver_mask);
        if (ret < 0 || ver_mask == 0) {
                ec_dev->mkbp_event_supported = 0;
        } else {
                ec_dev->mkbp_event_supported = fls(ver_mask);

                dev_dbg(ec_dev->dev, "MKBP support version %u\n", ec_dev->mkbp_event_supported - 1);
        }

        /* Probe if host sleep v1 is supported for S0ix failure detection. */
        ret = cros_ec_get_host_command_version_mask(ec_dev, EC_CMD_HOST_SLEEP_EVENT, &ver_mask);
        ec_dev->host_sleep_v1 = (ret == 0 && (ver_mask & EC_VER_MASK(1)));

        /* Get host event wake mask. */
        ret = cros_ec_get_host_event_wake_mask(ec_dev, &ec_dev->host_event_wake_mask);
        if (ret < 0) {
                /*
                 * If the EC doesn't support EC_CMD_HOST_EVENT_GET_WAKE_MASK,
                 * use a reasonable default. Note that we ignore various
                 * battery, AC status, and power-state events, because (a)
                 * those can be quite common (e.g., when sitting at full
                 * charge, on AC) and (b) these are not actionable wake events;
                 * if anything, we'd like to continue suspending (to save
                 * power), not wake up.
                 */
                ec_dev->host_event_wake_mask = U32_MAX &
                        ~(EC_HOST_EVENT_MASK(EC_HOST_EVENT_LID_CLOSED) |
                          EC_HOST_EVENT_MASK(EC_HOST_EVENT_AC_DISCONNECTED) |
                          EC_HOST_EVENT_MASK(EC_HOST_EVENT_BATTERY_LOW) |
                          EC_HOST_EVENT_MASK(EC_HOST_EVENT_BATTERY_CRITICAL) |
                          EC_HOST_EVENT_MASK(EC_HOST_EVENT_BATTERY) |
                          EC_HOST_EVENT_MASK(EC_HOST_EVENT_PD_MCU) |
                          EC_HOST_EVENT_MASK(EC_HOST_EVENT_BATTERY_STATUS));
                /*
                 * Old ECs may not support this command. Complain about all
                 * other errors.
                 */
                if (ret != -EOPNOTSUPP)
                        dev_err(ec_dev->dev,
                                "failed to retrieve wake mask: %d\n", ret);
        }

        ret = 0;

exit:
        return ret;
}
EXPORT_SYMBOL(cros_ec_query_all);

/**
 * cros_ec_cmd_xfer() - Send a command to the ChromeOS EC.
 * @ec_dev: EC device.
 * @msg: Message to write.
 *
 * Call this to send a command to the ChromeOS EC. This should be used instead
 * of calling the EC's cmd_xfer() callback directly. This function does not
 * convert EC command execution error codes to Linux error codes. Most
 * in-kernel users will want to use cros_ec_cmd_xfer_status() instead since
 * that function implements the conversion.
 *
 * Return:
 * >0 - EC command was executed successfully. The return value is the number
 *      of bytes returned by the EC (excluding the header).
 * =0 - EC communication was successful. EC command execution results are
 *      reported in msg->result. The result will be EC_RES_SUCCESS if the
 *      command was executed successfully or report an EC command execution
 *      error.
 * <0 - EC communication error. Return value is the Linux error code.
 */
int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev, struct cros_ec_command *msg)
{
        int ret;

        mutex_lock(&ec_dev->lock);
        if (ec_dev->proto_version == EC_PROTO_VERSION_UNKNOWN) {
                ret = cros_ec_query_all(ec_dev);
                if (ret) {
                        dev_err(ec_dev->dev,
                                "EC version unknown and query failed; aborting command\n");
                        mutex_unlock(&ec_dev->lock);
                        return ret;
                }
        }

        if (msg->insize > ec_dev->max_response) {
                dev_dbg(ec_dev->dev, "clamping message receive buffer\n");
                msg->insize = ec_dev->max_response;
        }

        if (msg->command < EC_CMD_PASSTHRU_OFFSET(CROS_EC_DEV_PD_INDEX)) {
                if (msg->outsize > ec_dev->max_request) {
                        dev_err(ec_dev->dev,
                                "request of size %u is too big (max: %u)\n",
                                msg->outsize,
                                ec_dev->max_request);
                        mutex_unlock(&ec_dev->lock);
                        return -EMSGSIZE;
                }
        } else {
                if (msg->outsize > ec_dev->max_passthru) {
                        dev_err(ec_dev->dev,
                                "passthru rq of size %u is too big (max: %u)\n",
                                msg->outsize,
                                ec_dev->max_passthru);
                        mutex_unlock(&ec_dev->lock);
                        return -EMSGSIZE;
                }
        }

        ret = cros_ec_send_command(ec_dev, msg);
        mutex_unlock(&ec_dev->lock);

        return ret;
}
EXPORT_SYMBOL(cros_ec_cmd_xfer);

/**
 * cros_ec_cmd_xfer_status() - Send a command to the ChromeOS EC.
 * @ec_dev: EC device.
 * @msg: Message to write.
 *
 * Call this to send a command to the ChromeOS EC. This should be used instead of calling the EC's
 * cmd_xfer() callback directly. It returns success status only if both the command was transmitted
 * successfully and the EC replied with success status.
 *
 * Return:
 * >=0 - The number of bytes transferred.
 * <0 - Linux error code
 */
int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
                            struct cros_ec_command *msg)
{
        int ret, mapped;

        ret = cros_ec_cmd_xfer(ec_dev, msg);
        if (ret < 0)
                return ret;

        mapped = cros_ec_map_error(msg->result);
        if (mapped) {
                dev_dbg(ec_dev->dev, "Command result (err: %d [%d])\n",
                        msg->result, mapped);
                ret = mapped;
        }

        return ret;
}
EXPORT_SYMBOL(cros_ec_cmd_xfer_status);

static int get_next_event_xfer(struct cros_ec_device *ec_dev,
                               struct cros_ec_command *msg,
                               struct ec_response_get_next_event_v3 *event,
                               int version, uint32_t size)
{
        int ret;

        msg->version = version;
        msg->command = EC_CMD_GET_NEXT_EVENT;
        msg->insize = size;
        msg->outsize = 0;

        ret = cros_ec_cmd_xfer_status(ec_dev, msg);
        if (ret > 0) {
                ec_dev->event_size = ret - 1;
                ec_dev->event_data = *event;
        }

        return ret;
}

static int get_next_event(struct cros_ec_device *ec_dev)
{
        DEFINE_RAW_FLEX(struct cros_ec_command, msg, data,
                        sizeof(struct ec_response_get_next_event_v3));
        struct ec_response_get_next_event_v3 *event =
                        (struct ec_response_get_next_event_v3 *)msg->data;
        int cmd_version = ec_dev->mkbp_event_supported - 1;
        u32 size;

        if (ec_dev->suspended) {
                dev_dbg(ec_dev->dev, "Device suspended.\n");
                return -EHOSTDOWN;
        }

        if (cmd_version == 0) {
                size = sizeof(struct ec_response_get_next_event);
        } else if (cmd_version < 3) {
                size = sizeof(struct ec_response_get_next_event_v1);
        } else {
                /*
                 * The max version we support is v3. So, we speak v3 even if the
                 * EC says it supports v4+.
                 */
                cmd_version = 3;
                size = sizeof(struct ec_response_get_next_event_v3);
        }

        return get_next_event_xfer(ec_dev, msg, event, cmd_version, size);
}

static int get_keyboard_state_event(struct cros_ec_device *ec_dev)
{
        u8 buffer[sizeof(struct cros_ec_command) +
                  sizeof(ec_dev->event_data.data)];
        struct cros_ec_command *msg = (struct cros_ec_command *)&buffer;

        msg->version = 0;
        msg->command = EC_CMD_MKBP_STATE;
        msg->insize = sizeof(ec_dev->event_data.data);
        msg->outsize = 0;

        ec_dev->event_size = cros_ec_cmd_xfer_status(ec_dev, msg);
        ec_dev->event_data.event_type = EC_MKBP_EVENT_KEY_MATRIX;
        memcpy(&ec_dev->event_data.data, msg->data,
               sizeof(ec_dev->event_data.data));

        return ec_dev->event_size;
}

/**
 * cros_ec_get_next_event() - Fetch next event from the ChromeOS EC.
 * @ec_dev: Device to fetch event from.
 * @wake_event: Pointer to a bool set to true upon return if the event might be
 *              treated as a wake event. Ignored if null.
 * @has_more_events: Pointer to bool set to true if more than one event is
 *              pending.
 *              Some EC will set this flag to indicate cros_ec_get_next_event()
 *              can be called multiple times in a row.
 *              It is an optimization to prevent issuing a EC command for
 *              nothing or wait for another interrupt from the EC to process
 *              the next message.
 *              Ignored if null.
 *
 * Return: negative error code on errors; 0 for no data; or else number of
 * bytes received (i.e., an event was retrieved successfully). Event types are
 * written out to @ec_dev->event_data.event_type on success.
 */
int cros_ec_get_next_event(struct cros_ec_device *ec_dev,
                           bool *wake_event,
                           bool *has_more_events)
{
        u8 event_type;
        u32 host_event;
        int ret;
        u32 ver_mask;

        /*
         * Default value for wake_event.
         * Wake up on keyboard event, wake up for spurious interrupt or link
         * error to the EC.
         */
        if (wake_event)
                *wake_event = true;

        /*
         * Default value for has_more_events.
         * EC will raise another interrupt if AP does not process all events
         * anyway.
         */
        if (has_more_events)
                *has_more_events = false;

        if (!ec_dev->mkbp_event_supported)
                return get_keyboard_state_event(ec_dev);

        ret = get_next_event(ec_dev);
        /*
         * -ENOPROTOOPT is returned when EC returns EC_RES_INVALID_VERSION.
         * This can occur when EC based device (e.g. Fingerprint MCU) jumps to
         * the RO image which doesn't support newer version of the command. In
         * this case we will attempt to update maximum supported version of the
         * EC_CMD_GET_NEXT_EVENT.
         */
        if (ret == -ENOPROTOOPT) {
                dev_dbg(ec_dev->dev,
                        "GET_NEXT_EVENT returned invalid version error.\n");
                mutex_lock(&ec_dev->lock);
                ret = cros_ec_get_host_command_version_mask(ec_dev,
                                                        EC_CMD_GET_NEXT_EVENT,
                                                        &ver_mask);
                mutex_unlock(&ec_dev->lock);
                if (ret < 0 || ver_mask == 0)
                        /*
                         * Do not change the MKBP supported version if we can't
                         * obtain supported version correctly. Please note that
                         * calling EC_CMD_GET_NEXT_EVENT returned
                         * EC_RES_INVALID_VERSION which means that the command
                         * is present.
                         */
                        return -ENOPROTOOPT;

                ec_dev->mkbp_event_supported = fls(ver_mask);
                dev_dbg(ec_dev->dev, "MKBP support version changed to %u\n",
                        ec_dev->mkbp_event_supported - 1);

                /* Try to get next event with new MKBP support version set. */
                ret = get_next_event(ec_dev);
        }

        if (ret <= 0)
                return ret;

        if (has_more_events)
                *has_more_events = ec_dev->event_data.event_type &
                        EC_MKBP_HAS_MORE_EVENTS;
        ec_dev->event_data.event_type &= EC_MKBP_EVENT_TYPE_MASK;

        if (wake_event) {
                event_type = ec_dev->event_data.event_type;
                host_event = cros_ec_get_host_event(ec_dev);

                /*
                 * Sensor events need to be parsed by the sensor sub-device.
                 * Defer them, and don't report the wakeup here.
                 */
                if (event_type == EC_MKBP_EVENT_SENSOR_FIFO) {
                        *wake_event = false;
                } else if (host_event) {
                        /* rtc_update_irq() already handles wakeup events. */
                        if (host_event & EC_HOST_EVENT_MASK(EC_HOST_EVENT_RTC))
                                *wake_event = false;
                        /* Masked host-events should not count as wake events. */
                        if (!(host_event & ec_dev->host_event_wake_mask))
                                *wake_event = false;
                }
        }

        return ret;
}
EXPORT_SYMBOL(cros_ec_get_next_event);

/**
 * cros_ec_get_host_event() - Return a mask of event set by the ChromeOS EC.
 * @ec_dev: Device to fetch event from.
 *
 * When MKBP is supported, when the EC raises an interrupt, we collect the
 * events raised and call the functions in the ec notifier. This function
 * is a helper to know which events are raised.
 *
 * Return: 0 on error or non-zero bitmask of one or more EC_HOST_EVENT_*.
 */
u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev)
{
        u32 host_event;

        if (!ec_dev->mkbp_event_supported)
                return 0;

        if (ec_dev->event_data.event_type != EC_MKBP_EVENT_HOST_EVENT)
                return 0;

        if (ec_dev->event_size != sizeof(host_event)) {
                dev_warn(ec_dev->dev, "Invalid host event size\n");
                return 0;
        }

        host_event = get_unaligned_le32(&ec_dev->event_data.data.host_event);

        return host_event;
}
EXPORT_SYMBOL(cros_ec_get_host_event);

/**
 * cros_ec_check_features() - Test for the presence of EC features
 *
 * @ec: EC device, does not have to be connected directly to the AP,
 *      can be daisy chained through another device.
 * @feature: One of ec_feature_code bit.
 *
 * Call this function to test whether the ChromeOS EC supports a feature.
 *
 * Return: true if supported, false if not (or if an error was encountered).
 */
bool cros_ec_check_features(struct cros_ec_dev *ec, int feature)
{
        struct ec_response_get_features *features = &ec->features;
        int ret;

        if (features->flags[0] == -1U && features->flags[1] == -1U) {
                /* features bitmap not read yet */
                ret = cros_ec_cmd(ec->ec_dev, 0, EC_CMD_GET_FEATURES + ec->cmd_offset,
                                  NULL, 0, features, sizeof(*features));
                if (ret < 0) {
                        dev_warn(ec->dev, "cannot get EC features: %d\n", ret);
                        memset(features, 0, sizeof(*features));
                }

                dev_dbg(ec->dev, "EC features %08x %08x\n",
                        features->flags[0], features->flags[1]);
        }

        return !!(features->flags[feature / 32] & EC_FEATURE_MASK_0(feature));
}
EXPORT_SYMBOL_GPL(cros_ec_check_features);

/**
 * cros_ec_get_sensor_count() - Return the number of MEMS sensors supported.
 *
 * @ec: EC device, does not have to be connected directly to the AP,
 *      can be daisy chained through another device.
 * Return: < 0 in case of error.
 */
int cros_ec_get_sensor_count(struct cros_ec_dev *ec)
{
        /*
         * Issue a command to get the number of sensor reported.
         * If not supported, check for legacy mode.
         */
        int ret, sensor_count;
        struct ec_params_motion_sense *params;
        struct ec_response_motion_sense *resp;
        struct cros_ec_command *msg;
        struct cros_ec_device *ec_dev = ec->ec_dev;
        u8 status;

        msg = kzalloc(sizeof(*msg) + max(sizeof(*params), sizeof(*resp)),
                      GFP_KERNEL);
        if (!msg)
                return -ENOMEM;

        msg->version = 1;
        msg->command = EC_CMD_MOTION_SENSE_CMD + ec->cmd_offset;
        msg->outsize = sizeof(*params);
        msg->insize = sizeof(*resp);

        params = (struct ec_params_motion_sense *)msg->data;
        params->cmd = MOTIONSENSE_CMD_DUMP;

        ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
        if (ret < 0) {
                sensor_count = ret;
        } else {
                resp = (struct ec_response_motion_sense *)msg->data;
                sensor_count = resp->dump.sensor_count;
        }
        kfree(msg);

        /*
         * Check legacy mode: Let's find out if sensors are accessible
         * via LPC interface.
         */
        if (sensor_count < 0 && ec->cmd_offset == 0 && ec_dev->cmd_readmem) {
                ret = ec_dev->cmd_readmem(ec_dev, EC_MEMMAP_ACC_STATUS,
                                1, &status);
                if (ret >= 0 &&
                    (status & EC_MEMMAP_ACC_STATUS_PRESENCE_BIT)) {
                        /*
                         * We have 2 sensors, one in the lid, one in the base.
                         */
                        sensor_count = 2;
                } else {
                        /*
                         * EC uses LPC interface and no sensors are presented.
                         */
                        sensor_count = 0;
                }
        }
        return sensor_count;
}
EXPORT_SYMBOL_GPL(cros_ec_get_sensor_count);

/**
 * cros_ec_cmd - Send a command to the EC.
 *
 * @ec_dev: EC device
 * @version: EC command version
 * @command: EC command
 * @outdata: EC command output data
 * @outsize: Size of outdata
 * @indata: EC command input data
 * @insize: Size of indata
 *
 * Return: >= 0 on success, negative error number on failure.
 */
int cros_ec_cmd(struct cros_ec_device *ec_dev,
                unsigned int version,
                int command,
                const void *outdata,
                size_t outsize,
                void *indata,
                size_t insize)
{
        struct cros_ec_command *msg;
        int ret;

        msg = kzalloc(sizeof(*msg) + max(insize, outsize), GFP_KERNEL);
        if (!msg)
                return -ENOMEM;

        msg->version = version;
        msg->command = command;
        msg->outsize = outsize;
        msg->insize = insize;

        if (outsize)
                memcpy(msg->data, outdata, outsize);

        ret = cros_ec_cmd_xfer_status(ec_dev, msg);
        if (ret < 0)
                goto error;

        if (insize)
                memcpy(indata, msg->data, insize);
error:
        kfree(msg);
        return ret;
}
EXPORT_SYMBOL_GPL(cros_ec_cmd);

/**
 * cros_ec_cmd_readmem - Read from EC memory.
 *
 * @ec_dev: EC device
 * @offset: Is within EC_LPC_ADDR_MEMMAP region.
 * @size: Number of bytes to read.
 * @dest: EC command output data
 *
 * Return: >= 0 on success, negative error number on failure.
 */
int cros_ec_cmd_readmem(struct cros_ec_device *ec_dev, u8 offset, u8 size, void *dest)
{
        struct ec_params_read_memmap params = {};

        if (!size)
                return -EINVAL;

        if (ec_dev->cmd_readmem)
                return ec_dev->cmd_readmem(ec_dev, offset, size, dest);

        params.offset = offset;
        params.size = size;
        return cros_ec_cmd(ec_dev, 0, EC_CMD_READ_MEMMAP,
                           &params, sizeof(params), dest, size);
}
EXPORT_SYMBOL_GPL(cros_ec_cmd_readmem);

/**
 * cros_ec_get_cmd_versions - Get supported version mask.
 *
 * @ec_dev: EC device
 * @cmd: Command to test
 *
 * Return: version mask on success, negative error number on failure.
 */
int cros_ec_get_cmd_versions(struct cros_ec_device *ec_dev, u16 cmd)
{
        struct ec_params_get_cmd_versions req_v0;
        struct ec_params_get_cmd_versions_v1 req_v1;
        struct ec_response_get_cmd_versions resp;
        int ret;

        if (cmd <= U8_MAX) {
                req_v0.cmd = cmd;
                ret = cros_ec_cmd(ec_dev, 0, EC_CMD_GET_CMD_VERSIONS,
                                  &req_v0, sizeof(req_v0), &resp, sizeof(resp));
        } else {
                req_v1.cmd = cmd;
                ret = cros_ec_cmd(ec_dev, 1, EC_CMD_GET_CMD_VERSIONS,
                                  &req_v1, sizeof(req_v1), &resp, sizeof(resp));
        }

        if (ret == -EINVAL)
                return 0; /* Command not implemented */
        else if (ret < 0)
                return ret;
        else
                return resp.version_mask;
}
EXPORT_SYMBOL_GPL(cros_ec_get_cmd_versions);

/**
 * cros_ec_device_registered - Return if the ec_dev is registered.
 *
 * @ec_dev: EC device
 *
 * Return: true if registered.  Otherwise, false.
 */
bool cros_ec_device_registered(struct cros_ec_device *ec_dev)
{
        guard(mutex)(&ec_dev->lock);
        return ec_dev->registered;
}
EXPORT_SYMBOL_GPL(cros_ec_device_registered);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("ChromeOS EC communication protocol helpers");