1 // SPDX-License-Identifier: GPL-2.0
2 //
3 // Copyright 2018 Google LLC.
4
5 #include <linux/completion.h>
6 #include <linux/delay.h>
7 #include <linux/kernel.h>
8 #include <linux/module.h>
9 #include <linux/of.h>
10 #include <linux/platform_data/cros_ec_commands.h>
11 #include <linux/platform_data/cros_ec_proto.h>
12 #include <linux/platform_device.h>
13 #include <linux/rpmsg.h>
14 #include <linux/slab.h>
15
16 #include "cros_ec.h"
17
18 #define EC_MSG_TIMEOUT_MS 200
19 #define HOST_COMMAND_MARK 1
20 #define HOST_EVENT_MARK 2
21
22 /**
23 * struct cros_ec_rpmsg_response - rpmsg message format from from EC.
24 *
25 * @type: The type of message, should be either HOST_COMMAND_MARK or
26 * HOST_EVENT_MARK, representing that the message is a response to
27 * host command, or a host event.
28 * @data: ec_host_response for host command.
29 */
30 struct cros_ec_rpmsg_response {
31 u8 type;
32 u8 data[] __aligned(4);
33 };
34
35 /**
36 * struct cros_ec_rpmsg - information about a EC over rpmsg.
37 *
38 * @rpdev: rpmsg device we are connected to
39 * @xfer_ack: completion for host command transfer.
40 * @host_event_work: Work struct for pending host event.
41 * @ept: The rpmsg endpoint of this channel.
42 * @has_pending_host_event: Boolean used to check if there is a pending event.
43 * @probe_done: Flag to indicate that probe is done.
44 */
45 struct cros_ec_rpmsg {
46 struct rpmsg_device *rpdev;
47 struct completion xfer_ack;
48 struct work_struct host_event_work;
49 struct rpmsg_endpoint *ept;
50 bool has_pending_host_event;
51 bool probe_done;
52 };
53
54 /**
55 * cros_ec_cmd_xfer_rpmsg - Transfer a message over rpmsg and receive the reply
56 *
57 * @ec_dev: ChromeOS EC device
58 * @ec_msg: Message to transfer
59 *
60 * This is only used for old EC proto version, and is not supported for this
61 * driver.
62 *
63 * Return: -EINVAL
64 */
cros_ec_cmd_xfer_rpmsg(struct cros_ec_device * ec_dev,struct cros_ec_command * ec_msg)65 static int cros_ec_cmd_xfer_rpmsg(struct cros_ec_device *ec_dev,
66 struct cros_ec_command *ec_msg)
67 {
68 return -EINVAL;
69 }
70
71 /**
72 * cros_ec_pkt_xfer_rpmsg - Transfer a packet over rpmsg and receive the reply
73 *
74 * @ec_dev: ChromeOS EC device
75 * @ec_msg: Message to transfer
76 *
77 * Return: number of bytes of the reply on success or negative error code.
78 */
cros_ec_pkt_xfer_rpmsg(struct cros_ec_device * ec_dev,struct cros_ec_command * ec_msg)79 static int cros_ec_pkt_xfer_rpmsg(struct cros_ec_device *ec_dev,
80 struct cros_ec_command *ec_msg)
81 {
82 struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
83 struct ec_host_response *response;
84 unsigned long timeout;
85 int len;
86 int ret;
87 u8 sum;
88 int i;
89
90 ec_msg->result = 0;
91 len = cros_ec_prepare_tx(ec_dev, ec_msg);
92 if (len < 0)
93 return len;
94 dev_dbg(ec_dev->dev, "prepared, len=%d\n", len);
95
96 reinit_completion(&ec_rpmsg->xfer_ack);
97 ret = rpmsg_send(ec_rpmsg->ept, ec_dev->dout, len);
98 if (ret) {
99 dev_err(ec_dev->dev, "rpmsg send failed\n");
100 return ret;
101 }
102
103 timeout = msecs_to_jiffies(EC_MSG_TIMEOUT_MS);
104 ret = wait_for_completion_timeout(&ec_rpmsg->xfer_ack, timeout);
105 if (!ret) {
106 dev_err(ec_dev->dev, "rpmsg send timeout\n");
107 return -EIO;
108 }
109
110 /* check response error code */
111 response = (struct ec_host_response *)ec_dev->din;
112 ec_msg->result = response->result;
113
114 ret = cros_ec_check_result(ec_dev, ec_msg);
115 if (ret)
116 goto exit;
117
118 if (response->data_len > ec_msg->insize) {
119 dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)",
120 response->data_len, ec_msg->insize);
121 ret = -EMSGSIZE;
122 goto exit;
123 }
124
125 /* copy response packet payload and compute checksum */
126 memcpy(ec_msg->data, ec_dev->din + sizeof(*response),
127 response->data_len);
128
129 sum = 0;
130 for (i = 0; i < sizeof(*response) + response->data_len; i++)
131 sum += ec_dev->din[i];
132
133 if (sum) {
134 dev_err(ec_dev->dev, "bad packet checksum, calculated %x\n",
135 sum);
136 ret = -EBADMSG;
137 goto exit;
138 }
139
140 ret = response->data_len;
141 exit:
142 if (ec_msg->command == EC_CMD_REBOOT_EC)
143 msleep(EC_REBOOT_DELAY_MS);
144
145 return ret;
146 }
147
148 static void
cros_ec_rpmsg_host_event_function(struct work_struct * host_event_work)149 cros_ec_rpmsg_host_event_function(struct work_struct *host_event_work)
150 {
151 struct cros_ec_rpmsg *ec_rpmsg = container_of(host_event_work,
152 struct cros_ec_rpmsg,
153 host_event_work);
154
155 cros_ec_irq_thread(0, dev_get_drvdata(&ec_rpmsg->rpdev->dev));
156 }
157
cros_ec_rpmsg_callback(struct rpmsg_device * rpdev,void * data,int len,void * priv,u32 src)158 static int cros_ec_rpmsg_callback(struct rpmsg_device *rpdev, void *data,
159 int len, void *priv, u32 src)
160 {
161 struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev);
162 struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
163 struct cros_ec_rpmsg_response *resp;
164
165 if (!len) {
166 dev_warn(ec_dev->dev, "rpmsg received empty response");
167 return -EINVAL;
168 }
169
170 resp = data;
171 len -= offsetof(struct cros_ec_rpmsg_response, data);
172 if (resp->type == HOST_COMMAND_MARK) {
173 if (len > ec_dev->din_size) {
174 dev_warn(ec_dev->dev,
175 "received length %d > din_size %d, truncating",
176 len, ec_dev->din_size);
177 len = ec_dev->din_size;
178 }
179
180 memcpy(ec_dev->din, resp->data, len);
181 complete(&ec_rpmsg->xfer_ack);
182 } else if (resp->type == HOST_EVENT_MARK) {
183 /*
184 * If the host event is sent before cros_ec_register is
185 * finished, queue the host event.
186 */
187 if (ec_rpmsg->probe_done)
188 schedule_work(&ec_rpmsg->host_event_work);
189 else
190 ec_rpmsg->has_pending_host_event = true;
191 } else {
192 dev_warn(ec_dev->dev, "rpmsg received invalid type = %d",
193 resp->type);
194 return -EINVAL;
195 }
196
197 return 0;
198 }
199
200 static struct rpmsg_endpoint *
cros_ec_rpmsg_create_ept(struct rpmsg_device * rpdev)201 cros_ec_rpmsg_create_ept(struct rpmsg_device *rpdev)
202 {
203 struct rpmsg_channel_info chinfo = {};
204
205 strscpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE);
206 chinfo.src = rpdev->src;
207 chinfo.dst = RPMSG_ADDR_ANY;
208
209 return rpmsg_create_ept(rpdev, cros_ec_rpmsg_callback, NULL, chinfo);
210 }
211
cros_ec_rpmsg_probe(struct rpmsg_device * rpdev)212 static int cros_ec_rpmsg_probe(struct rpmsg_device *rpdev)
213 {
214 struct device *dev = &rpdev->dev;
215 struct cros_ec_rpmsg *ec_rpmsg;
216 struct cros_ec_device *ec_dev;
217 int ret;
218
219 ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
220 if (!ec_dev)
221 return -ENOMEM;
222
223 ec_rpmsg = devm_kzalloc(dev, sizeof(*ec_rpmsg), GFP_KERNEL);
224 if (!ec_rpmsg)
225 return -ENOMEM;
226
227 ec_dev->dev = dev;
228 ec_dev->priv = ec_rpmsg;
229 ec_dev->cmd_xfer = cros_ec_cmd_xfer_rpmsg;
230 ec_dev->pkt_xfer = cros_ec_pkt_xfer_rpmsg;
231 ec_dev->phys_name = dev_name(&rpdev->dev);
232 ec_dev->din_size = sizeof(struct ec_host_response) +
233 sizeof(struct ec_response_get_protocol_info);
234 ec_dev->dout_size = sizeof(struct ec_host_request);
235 dev_set_drvdata(dev, ec_dev);
236
237 ec_rpmsg->rpdev = rpdev;
238 init_completion(&ec_rpmsg->xfer_ack);
239 INIT_WORK(&ec_rpmsg->host_event_work,
240 cros_ec_rpmsg_host_event_function);
241
242 ec_rpmsg->ept = cros_ec_rpmsg_create_ept(rpdev);
243 if (!ec_rpmsg->ept)
244 return -ENOMEM;
245
246 ret = cros_ec_register(ec_dev);
247 if (ret < 0) {
248 rpmsg_destroy_ept(ec_rpmsg->ept);
249 cancel_work_sync(&ec_rpmsg->host_event_work);
250 return ret;
251 }
252
253 ec_rpmsg->probe_done = true;
254
255 if (ec_rpmsg->has_pending_host_event)
256 schedule_work(&ec_rpmsg->host_event_work);
257
258 return 0;
259 }
260
cros_ec_rpmsg_remove(struct rpmsg_device * rpdev)261 static void cros_ec_rpmsg_remove(struct rpmsg_device *rpdev)
262 {
263 struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev);
264 struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
265
266 cros_ec_unregister(ec_dev);
267 rpmsg_destroy_ept(ec_rpmsg->ept);
268 cancel_work_sync(&ec_rpmsg->host_event_work);
269 }
270
271 #ifdef CONFIG_PM_SLEEP
cros_ec_rpmsg_suspend(struct device * dev)272 static int cros_ec_rpmsg_suspend(struct device *dev)
273 {
274 struct cros_ec_device *ec_dev = dev_get_drvdata(dev);
275
276 return cros_ec_suspend(ec_dev);
277 }
278
cros_ec_rpmsg_resume(struct device * dev)279 static int cros_ec_rpmsg_resume(struct device *dev)
280 {
281 struct cros_ec_device *ec_dev = dev_get_drvdata(dev);
282
283 return cros_ec_resume(ec_dev);
284 }
285 #endif
286
287 static SIMPLE_DEV_PM_OPS(cros_ec_rpmsg_pm_ops, cros_ec_rpmsg_suspend,
288 cros_ec_rpmsg_resume);
289
290 static const struct of_device_id cros_ec_rpmsg_of_match[] = {
291 { .compatible = "google,cros-ec-rpmsg", },
292 { }
293 };
294 MODULE_DEVICE_TABLE(of, cros_ec_rpmsg_of_match);
295
296 static struct rpmsg_driver cros_ec_driver_rpmsg = {
297 .drv = {
298 .name = "cros-ec-rpmsg",
299 .of_match_table = cros_ec_rpmsg_of_match,
300 .pm = &cros_ec_rpmsg_pm_ops,
301 },
302 .probe = cros_ec_rpmsg_probe,
303 .remove = cros_ec_rpmsg_remove,
304 };
305
306 module_rpmsg_driver(cros_ec_driver_rpmsg);
307
308 MODULE_LICENSE("GPL v2");
309 MODULE_DESCRIPTION("ChromeOS EC multi function device (rpmsg)");
310