diff options
Diffstat (limited to 'drivers/platform/chrome/cros_ec_rpmsg.c')
| -rw-r--r-- | drivers/platform/chrome/cros_ec_rpmsg.c | 258 |
1 files changed, 258 insertions, 0 deletions
diff --git a/drivers/platform/chrome/cros_ec_rpmsg.c b/drivers/platform/chrome/cros_ec_rpmsg.c new file mode 100644 index 000000000000..5d3fb2abad1d --- /dev/null +++ b/drivers/platform/chrome/cros_ec_rpmsg.c @@ -0,0 +1,258 @@ +// 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/mfd/cros_ec.h> +#include <linux/mfd/cros_ec_commands.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/rpmsg.h> +#include <linux/slab.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. + */ +struct cros_ec_rpmsg { + struct rpmsg_device *rpdev; + struct completion xfer_ack; + struct work_struct host_event_work; +}; + +/** + * 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 rpmsg_device *rpdev = ec_rpmsg->rpdev; + 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); + dev_dbg(ec_dev->dev, "prepared, len=%d\n", len); + + reinit_completion(&ec_rpmsg->xfer_ack); + ret = rpmsg_send(rpdev->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); + struct cros_ec_device *ec_dev = dev_get_drvdata(&ec_rpmsg->rpdev->dev); + bool wake_event = true; + int ret; + + ret = cros_ec_get_next_event(ec_dev, &wake_event); + + /* + * Signal only if wake host events or any interrupt if + * cros_ec_get_next_event() returned an error (default value for + * wake_event is true) + */ + if (wake_event && device_may_wakeup(ec_dev->dev)) + pm_wakeup_event(ec_dev->dev, 0); + + if (ret > 0) + blocking_notifier_call_chain(&ec_dev->event_notifier, + 0, ec_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) { + schedule_work(&ec_rpmsg->host_event_work); + } else { + dev_warn(ec_dev->dev, "rpmsg received invalid type = %d", + resp->type); + return -EINVAL; + } + + return 0; +} + +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; + + 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); + + return cros_ec_register(ec_dev); +} + +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; + + cancel_work_sync(&ec_rpmsg->host_event_work); +} + +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, + }, + .probe = cros_ec_rpmsg_probe, + .remove = cros_ec_rpmsg_remove, + .callback = cros_ec_rpmsg_callback, +}; + +module_rpmsg_driver(cros_ec_driver_rpmsg); + +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("ChromeOS EC multi function device (rpmsg)"); |