// SPDX-License-Identifier: GPL-2.0
//
// Copyright 2018 Google LLC.
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_data/cros_ec_commands.h>
#include <linux/platform_data/cros_ec_proto.h>
#include <linux/platform_device.h>
#include <linux/rpmsg.h>
#include <linux/slab.h>
#include "cros_ec.h"
#define EC_MSG_TIMEOUT_MS 200
#define HOST_COMMAND_MARK 1
#define HOST_EVENT_MARK 2
/**
* struct cros_ec_rpmsg_response - rpmsg message format from from EC.
*
* @type: The type of message, should be either HOST_COMMAND_MARK or
* HOST_EVENT_MARK, representing that the message is a response to
* host command, or a host event.
* @data: ec_host_response for host command.
*/
struct cros_ec_rpmsg_response {
u8 type;
u8 data[] __aligned(4);
};
/**
* struct cros_ec_rpmsg - information about a EC over rpmsg.
*
* @rpdev: rpmsg device we are connected to
* @xfer_ack: completion for host command transfer.
* @host_event_work: Work struct for pending host event.
* @ept: The rpmsg endpoint of this channel.
* @has_pending_host_event: Boolean used to check if there is a pending event.
* @probe_done: Flag to indicate that probe is done.
*/
struct cros_ec_rpmsg {
struct rpmsg_device *rpdev;
struct completion xfer_ack;
struct work_struct host_event_work;
struct rpmsg_endpoint *ept;
bool has_pending_host_event;
bool probe_done;
};
/**
* cros_ec_cmd_xfer_rpmsg - Transfer a message over rpmsg and receive the reply
*
* @ec_dev: ChromeOS EC device
* @ec_msg: Message to transfer
*
* This is only used for old EC proto version, and is not supported for this
* driver.
*
* Return: -EINVAL
*/
static int cros_ec_cmd_xfer_rpmsg(struct cros_ec_device *ec_dev,
struct cros_ec_command *ec_msg)
{
return -EINVAL;
}
/**
* cros_ec_pkt_xfer_rpmsg - Transfer a packet over rpmsg and receive the reply
*
* @ec_dev: ChromeOS EC device
* @ec_msg: Message to transfer
*
* Return: number of bytes of the reply on success or negative error code.
*/
static int cros_ec_pkt_xfer_rpmsg(struct cros_ec_device *ec_dev,
struct cros_ec_command *ec_msg)
{
struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
struct ec_host_response *response;
unsigned long timeout;
int len;
int ret;
u8 sum;
int i;
ec_msg->result = 0;
len = cros_ec_prepare_tx(ec_dev, ec_msg);
if (len < 0)
return len;
dev_dbg(ec_dev->dev, "prepared, len=%d\n", len);
reinit_completion(&ec_rpmsg->xfer_ack);
ret = rpmsg_send(ec_rpmsg->ept, ec_dev->dout, len);
if (ret) {
dev_err(ec_dev->dev, "rpmsg send failed\n");
return ret;
}
timeout = msecs_to_jiffies(EC_MSG_TIMEOUT_MS);
ret = wait_for_completion_timeout(&ec_rpmsg->xfer_ack, timeout);
if (!ret) {
dev_err(ec_dev->dev, "rpmsg send timeout\n");
return -EIO;
}
/* check response error code */
response = (struct ec_host_response *)ec_dev->din;
ec_msg->result = response->result;
ret = cros_ec_check_result(ec_dev, ec_msg);
if (ret)
goto exit;
if (response->data_len > ec_msg->insize) {
dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)",
response->data_len, ec_msg->insize);
ret = -EMSGSIZE;
goto exit;
}
/* copy response packet payload and compute checksum */
memcpy(ec_msg->data, ec_dev->din + sizeof(*response),
response->data_len);
sum = 0;
for (i = 0; i < sizeof(*response) + response->data_len; i++)
sum += ec_dev->din[i];
if (sum) {
dev_err(ec_dev->dev, "bad packet checksum, calculated %x\n",
sum);
ret = -EBADMSG;
goto exit;
}
ret = response->data_len;
exit:
if (ec_msg->command == EC_CMD_REBOOT_EC)
msleep(EC_REBOOT_DELAY_MS);
return ret;
}
static void
cros_ec_rpmsg_host_event_function(struct work_struct *host_event_work)
{
struct cros_ec_rpmsg *ec_rpmsg = container_of(host_event_work,
struct cros_ec_rpmsg,
host_event_work);
cros_ec_irq_thread(0, dev_get_drvdata(&ec_rpmsg->rpdev->dev));
}
static int cros_ec_rpmsg_callback(struct rpmsg_device *rpdev, void *data,
int len, void *priv, u32 src)
{
struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev);
struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
struct cros_ec_rpmsg_response *resp;
if (!len) {
dev_warn(ec_dev->dev, "rpmsg received empty response");
return -EINVAL;
}
resp = data;
len -= offsetof(struct cros_ec_rpmsg_response, data);
if (resp->type == HOST_COMMAND_MARK) {
if (len > ec_dev->din_size) {
dev_warn(ec_dev->dev,
"received length %d > din_size %d, truncating",
len, ec_dev->din_size);
len = ec_dev->din_size;
}
memcpy(ec_dev->din, resp->data, len);
complete(&ec_rpmsg->xfer_ack);
} else if (resp->type == HOST_EVENT_MARK) {
/*
* If the host event is sent before cros_ec_register is
* finished, queue the host event.
*/
if (ec_rpmsg->probe_done)
schedule_work(&ec_rpmsg->host_event_work);
else
ec_rpmsg->has_pending_host_event = true;
} else {
dev_warn(ec_dev->dev, "rpmsg received invalid type = %d",
resp->type);
return -EINVAL;
}
return 0;
}
static struct rpmsg_endpoint *
cros_ec_rpmsg_create_ept(struct rpmsg_device *rpdev)
{
struct rpmsg_channel_info chinfo = {};
strscpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE);
chinfo.src = rpdev->src;
chinfo.dst = RPMSG_ADDR_ANY;
return rpmsg_create_ept(rpdev, cros_ec_rpmsg_callback, NULL, chinfo);
}
static int cros_ec_rpmsg_probe(struct rpmsg_device *rpdev)
{
struct device *dev = &rpdev->dev;
struct cros_ec_rpmsg *ec_rpmsg;
struct cros_ec_device *ec_dev;
int ret;
ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
if (!ec_dev)
return -ENOMEM;
ec_rpmsg = devm_kzalloc(dev, sizeof(*ec_rpmsg), GFP_KERNEL);
if (!ec_rpmsg)
return -ENOMEM;
ec_dev->dev = dev;
ec_dev->priv = ec_rpmsg;
ec_dev->cmd_xfer = cros_ec_cmd_xfer_rpmsg;
ec_dev->pkt_xfer = cros_ec_pkt_xfer_rpmsg;
ec_dev->phys_name = dev_name(&rpdev->dev);
ec_dev->din_size = sizeof(struct ec_host_response) +
sizeof(struct ec_response_get_protocol_info);
ec_dev->dout_size = sizeof(struct ec_host_request);
dev_set_drvdata(dev, ec_dev);
ec_rpmsg->rpdev = rpdev;
init_completion(&ec_rpmsg->xfer_ack);
INIT_WORK(&ec_rpmsg->host_event_work,
cros_ec_rpmsg_host_event_function);
ec_rpmsg->ept = cros_ec_rpmsg_create_ept(rpdev);
if (!ec_rpmsg->ept)
return -ENOMEM;
ret = cros_ec_register(ec_dev);
if (ret < 0) {
rpmsg_destroy_ept(ec_rpmsg->ept);
cancel_work_sync(&ec_rpmsg->host_event_work);
return ret;
}
ec_rpmsg->probe_done = true;
if (ec_rpmsg->has_pending_host_event)
schedule_work(&ec_rpmsg->host_event_work);
return 0;
}
static void cros_ec_rpmsg_remove(struct rpmsg_device *rpdev)
{
struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev);
struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
cros_ec_unregister(ec_dev);
rpmsg_destroy_ept(ec_rpmsg->ept);
cancel_work_sync(&ec_rpmsg->host_event_work);
}
#ifdef CONFIG_PM_SLEEP
static int cros_ec_rpmsg_suspend(struct device *dev)
{
struct cros_ec_device *ec_dev = dev_get_drvdata(dev);
return cros_ec_suspend(ec_dev);
}
static int cros_ec_rpmsg_resume(struct device *dev)
{
struct cros_ec_device *ec_dev = dev_get_drvdata(dev);
return cros_ec_resume(ec_dev);
}
#endif
static SIMPLE_DEV_PM_OPS(cros_ec_rpmsg_pm_ops, cros_ec_rpmsg_suspend,
cros_ec_rpmsg_resume);
static const struct of_device_id cros_ec_rpmsg_of_match[] = {
{ .compatible = "google,cros-ec-rpmsg", },
{ }
};
MODULE_DEVICE_TABLE(of, cros_ec_rpmsg_of_match);
static struct rpmsg_driver cros_ec_driver_rpmsg = {
.drv = {
.name = "cros-ec-rpmsg",
.of_match_table = cros_ec_rpmsg_of_match,
.pm = &cros_ec_rpmsg_pm_ops,
},
.probe = cros_ec_rpmsg_probe,
.remove = cros_ec_rpmsg_remove,
};
module_rpmsg_driver(cros_ec_driver_rpmsg);
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("ChromeOS EC multi function device (rpmsg)");
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