![Pi-Hsun Shih](/assets/img/avatar_default.png)
Add EC host command support through rpmsg. Signed-off-by: Pi-Hsun Shih <pihsun@chromium.org> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
259 lines
6.6 KiB
C
259 lines
6.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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//
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// Copyright 2018 Google LLC.
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#include <linux/completion.h>
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#include <linux/delay.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/mfd/cros_ec.h>
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#include <linux/mfd/cros_ec_commands.h>
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#include <linux/of.h>
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#include <linux/platform_device.h>
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#include <linux/rpmsg.h>
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#include <linux/slab.h>
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#define EC_MSG_TIMEOUT_MS 200
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#define HOST_COMMAND_MARK 1
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#define HOST_EVENT_MARK 2
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/**
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* struct cros_ec_rpmsg_response - rpmsg message format from from EC.
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*
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* @type: The type of message, should be either HOST_COMMAND_MARK or
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* HOST_EVENT_MARK, representing that the message is a response to
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* host command, or a host event.
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* @data: ec_host_response for host command.
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*/
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struct cros_ec_rpmsg_response {
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u8 type;
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u8 data[] __aligned(4);
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};
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/**
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* struct cros_ec_rpmsg - information about a EC over rpmsg.
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*
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* @rpdev: rpmsg device we are connected to
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* @xfer_ack: completion for host command transfer.
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* @host_event_work: Work struct for pending host event.
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*/
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struct cros_ec_rpmsg {
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struct rpmsg_device *rpdev;
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struct completion xfer_ack;
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struct work_struct host_event_work;
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};
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/**
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* cros_ec_cmd_xfer_rpmsg - Transfer a message over rpmsg and receive the reply
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*
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* @ec_dev: ChromeOS EC device
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* @ec_msg: Message to transfer
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*
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* This is only used for old EC proto version, and is not supported for this
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* driver.
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*
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* Return: -EINVAL
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*/
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static int cros_ec_cmd_xfer_rpmsg(struct cros_ec_device *ec_dev,
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struct cros_ec_command *ec_msg)
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{
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return -EINVAL;
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}
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/**
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* cros_ec_pkt_xfer_rpmsg - Transfer a packet over rpmsg and receive the reply
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*
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* @ec_dev: ChromeOS EC device
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* @ec_msg: Message to transfer
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*
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* Return: number of bytes of the reply on success or negative error code.
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*/
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static int cros_ec_pkt_xfer_rpmsg(struct cros_ec_device *ec_dev,
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struct cros_ec_command *ec_msg)
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{
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struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
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struct rpmsg_device *rpdev = ec_rpmsg->rpdev;
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struct ec_host_response *response;
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unsigned long timeout;
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int len;
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int ret;
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u8 sum;
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int i;
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ec_msg->result = 0;
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len = cros_ec_prepare_tx(ec_dev, ec_msg);
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dev_dbg(ec_dev->dev, "prepared, len=%d\n", len);
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reinit_completion(&ec_rpmsg->xfer_ack);
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ret = rpmsg_send(rpdev->ept, ec_dev->dout, len);
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if (ret) {
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dev_err(ec_dev->dev, "rpmsg send failed\n");
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return ret;
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}
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timeout = msecs_to_jiffies(EC_MSG_TIMEOUT_MS);
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ret = wait_for_completion_timeout(&ec_rpmsg->xfer_ack, timeout);
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if (!ret) {
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dev_err(ec_dev->dev, "rpmsg send timeout\n");
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return -EIO;
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}
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/* check response error code */
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response = (struct ec_host_response *)ec_dev->din;
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ec_msg->result = response->result;
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ret = cros_ec_check_result(ec_dev, ec_msg);
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if (ret)
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goto exit;
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if (response->data_len > ec_msg->insize) {
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dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)",
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response->data_len, ec_msg->insize);
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ret = -EMSGSIZE;
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goto exit;
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}
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/* copy response packet payload and compute checksum */
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memcpy(ec_msg->data, ec_dev->din + sizeof(*response),
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response->data_len);
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sum = 0;
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for (i = 0; i < sizeof(*response) + response->data_len; i++)
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sum += ec_dev->din[i];
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if (sum) {
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dev_err(ec_dev->dev, "bad packet checksum, calculated %x\n",
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sum);
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ret = -EBADMSG;
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goto exit;
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}
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ret = response->data_len;
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exit:
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if (ec_msg->command == EC_CMD_REBOOT_EC)
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msleep(EC_REBOOT_DELAY_MS);
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return ret;
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}
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static void
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cros_ec_rpmsg_host_event_function(struct work_struct *host_event_work)
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{
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struct cros_ec_rpmsg *ec_rpmsg = container_of(host_event_work,
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struct cros_ec_rpmsg,
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host_event_work);
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struct cros_ec_device *ec_dev = dev_get_drvdata(&ec_rpmsg->rpdev->dev);
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bool wake_event = true;
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int ret;
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ret = cros_ec_get_next_event(ec_dev, &wake_event);
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/*
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* Signal only if wake host events or any interrupt if
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* cros_ec_get_next_event() returned an error (default value for
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* wake_event is true)
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*/
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if (wake_event && device_may_wakeup(ec_dev->dev))
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pm_wakeup_event(ec_dev->dev, 0);
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if (ret > 0)
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blocking_notifier_call_chain(&ec_dev->event_notifier,
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0, ec_dev);
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}
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static int cros_ec_rpmsg_callback(struct rpmsg_device *rpdev, void *data,
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int len, void *priv, u32 src)
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{
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struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev);
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struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
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struct cros_ec_rpmsg_response *resp;
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if (!len) {
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dev_warn(ec_dev->dev, "rpmsg received empty response");
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return -EINVAL;
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}
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resp = data;
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len -= offsetof(struct cros_ec_rpmsg_response, data);
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if (resp->type == HOST_COMMAND_MARK) {
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if (len > ec_dev->din_size) {
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dev_warn(ec_dev->dev,
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"received length %d > din_size %d, truncating",
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len, ec_dev->din_size);
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len = ec_dev->din_size;
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}
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memcpy(ec_dev->din, resp->data, len);
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complete(&ec_rpmsg->xfer_ack);
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} else if (resp->type == HOST_EVENT_MARK) {
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schedule_work(&ec_rpmsg->host_event_work);
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} else {
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dev_warn(ec_dev->dev, "rpmsg received invalid type = %d",
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resp->type);
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return -EINVAL;
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}
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return 0;
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}
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static int cros_ec_rpmsg_probe(struct rpmsg_device *rpdev)
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{
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struct device *dev = &rpdev->dev;
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struct cros_ec_rpmsg *ec_rpmsg;
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struct cros_ec_device *ec_dev;
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ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
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if (!ec_dev)
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return -ENOMEM;
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ec_rpmsg = devm_kzalloc(dev, sizeof(*ec_rpmsg), GFP_KERNEL);
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if (!ec_rpmsg)
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return -ENOMEM;
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ec_dev->dev = dev;
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ec_dev->priv = ec_rpmsg;
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ec_dev->cmd_xfer = cros_ec_cmd_xfer_rpmsg;
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ec_dev->pkt_xfer = cros_ec_pkt_xfer_rpmsg;
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ec_dev->phys_name = dev_name(&rpdev->dev);
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ec_dev->din_size = sizeof(struct ec_host_response) +
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sizeof(struct ec_response_get_protocol_info);
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ec_dev->dout_size = sizeof(struct ec_host_request);
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dev_set_drvdata(dev, ec_dev);
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ec_rpmsg->rpdev = rpdev;
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init_completion(&ec_rpmsg->xfer_ack);
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INIT_WORK(&ec_rpmsg->host_event_work,
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cros_ec_rpmsg_host_event_function);
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return cros_ec_register(ec_dev);
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}
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static void cros_ec_rpmsg_remove(struct rpmsg_device *rpdev)
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{
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struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev);
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struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
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cancel_work_sync(&ec_rpmsg->host_event_work);
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}
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static const struct of_device_id cros_ec_rpmsg_of_match[] = {
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{ .compatible = "google,cros-ec-rpmsg", },
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{ }
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};
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MODULE_DEVICE_TABLE(of, cros_ec_rpmsg_of_match);
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static struct rpmsg_driver cros_ec_driver_rpmsg = {
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.drv = {
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.name = "cros-ec-rpmsg",
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.of_match_table = cros_ec_rpmsg_of_match,
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},
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.probe = cros_ec_rpmsg_probe,
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.remove = cros_ec_rpmsg_remove,
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.callback = cros_ec_rpmsg_callback,
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};
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module_rpmsg_driver(cros_ec_driver_rpmsg);
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MODULE_LICENSE("GPL v2");
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MODULE_DESCRIPTION("ChromeOS EC multi function device (rpmsg)");
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