--- /dev/null
+// 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)");
projects / platform / kernel / linux-rpi.git / commitdiff