1 files changed, 309 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 000000000..39d3b50a7
--- /dev/null
+++ b/drivers/platform/chrome/cros_ec_rpmsg.c
@@ -0,0 +1,309 @@
+// 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)");