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 #define EC_MSG_TIMEOUT_MS 200
17 #define HOST_COMMAND_MARK 1
18 #define HOST_EVENT_MARK 2
19
20 /**
21 * struct cros_ec_rpmsg_response - rpmsg message format from from EC.
22 *
23 * @type: The type of message, should be either HOST_COMMAND_MARK or
24 * HOST_EVENT_MARK, representing that the message is a response to
25 * host command, or a host event.
26 * @data: ec_host_response for host command.
27 */
28 struct cros_ec_rpmsg_response {
29 u8 type;
30 u8 data[] __aligned(4);
31 };
32
33 /**
34 * struct cros_ec_rpmsg - information about a EC over rpmsg.
35 *
36 * @rpdev: rpmsg device we are connected to
37 * @xfer_ack: completion for host command transfer.
38 * @host_event_work: Work struct for pending host event.
39 */
40 struct cros_ec_rpmsg {
41 struct rpmsg_device *rpdev;
42 struct completion xfer_ack;
43 struct work_struct host_event_work;
44 struct rpmsg_endpoint *ept;
45 bool has_pending_host_event;
46 bool probe_done;
47 };
48
49 /**
50 * cros_ec_cmd_xfer_rpmsg - Transfer a message over rpmsg and receive the reply
51 *
52 * @ec_dev: ChromeOS EC device
53 * @ec_msg: Message to transfer
54 *
55 * This is only used for old EC proto version, and is not supported for this
56 * driver.
57 *
58 * Return: -EINVAL
59 */
cros_ec_cmd_xfer_rpmsg(struct cros_ec_device * ec_dev,struct cros_ec_command * ec_msg)60 static int cros_ec_cmd_xfer_rpmsg(struct cros_ec_device *ec_dev,
61 struct cros_ec_command *ec_msg)
62 {
63 return -EINVAL;
64 }
65
66 /**
67 * cros_ec_pkt_xfer_rpmsg - Transfer a packet over rpmsg and receive the reply
68 *
69 * @ec_dev: ChromeOS EC device
70 * @ec_msg: Message to transfer
71 *
72 * Return: number of bytes of the reply on success or negative error code.
73 */
cros_ec_pkt_xfer_rpmsg(struct cros_ec_device * ec_dev,struct cros_ec_command * ec_msg)74 static int cros_ec_pkt_xfer_rpmsg(struct cros_ec_device *ec_dev,
75 struct cros_ec_command *ec_msg)
76 {
77 struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
78 struct ec_host_response *response;
79 unsigned long timeout;
80 int len;
81 int ret;
82 u8 sum;
83 int i;
84
85 ec_msg->result = 0;
86 len = cros_ec_prepare_tx(ec_dev, ec_msg);
87 dev_dbg(ec_dev->dev, "prepared, len=%d\n", len);
88
89 reinit_completion(&ec_rpmsg->xfer_ack);
90 ret = rpmsg_send(ec_rpmsg->ept, ec_dev->dout, len);
91 if (ret) {
92 dev_err(ec_dev->dev, "rpmsg send failed\n");
93 return ret;
94 }
95
96 timeout = msecs_to_jiffies(EC_MSG_TIMEOUT_MS);
97 ret = wait_for_completion_timeout(&ec_rpmsg->xfer_ack, timeout);
98 if (!ret) {
99 dev_err(ec_dev->dev, "rpmsg send timeout\n");
100 return -EIO;
101 }
102
103 /* check response error code */
104 response = (struct ec_host_response *)ec_dev->din;
105 ec_msg->result = response->result;
106
107 ret = cros_ec_check_result(ec_dev, ec_msg);
108 if (ret)
109 goto exit;
110
111 if (response->data_len > ec_msg->insize) {
112 dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)",
113 response->data_len, ec_msg->insize);
114 ret = -EMSGSIZE;
115 goto exit;
116 }
117
118 /* copy response packet payload and compute checksum */
119 memcpy(ec_msg->data, ec_dev->din + sizeof(*response),
120 response->data_len);
121
122 sum = 0;
123 for (i = 0; i < sizeof(*response) + response->data_len; i++)
124 sum += ec_dev->din[i];
125
126 if (sum) {
127 dev_err(ec_dev->dev, "bad packet checksum, calculated %x\n",
128 sum);
129 ret = -EBADMSG;
130 goto exit;
131 }
132
133 ret = response->data_len;
134 exit:
135 if (ec_msg->command == EC_CMD_REBOOT_EC)
136 msleep(EC_REBOOT_DELAY_MS);
137
138 return ret;
139 }
140
141 static void
cros_ec_rpmsg_host_event_function(struct work_struct * host_event_work)142 cros_ec_rpmsg_host_event_function(struct work_struct *host_event_work)
143 {
144 struct cros_ec_rpmsg *ec_rpmsg = container_of(host_event_work,
145 struct cros_ec_rpmsg,
146 host_event_work);
147 struct cros_ec_device *ec_dev = dev_get_drvdata(&ec_rpmsg->rpdev->dev);
148 bool wake_event = true;
149 int ret;
150
151 ret = cros_ec_get_next_event(ec_dev, &wake_event);
152
153 /*
154 * Signal only if wake host events or any interrupt if
155 * cros_ec_get_next_event() returned an error (default value for
156 * wake_event is true)
157 */
158 if (wake_event && device_may_wakeup(ec_dev->dev))
159 pm_wakeup_event(ec_dev->dev, 0);
160
161 if (ret > 0)
162 blocking_notifier_call_chain(&ec_dev->event_notifier,
163 0, ec_dev);
164 }
165
cros_ec_rpmsg_callback(struct rpmsg_device * rpdev,void * data,int len,void * priv,u32 src)166 static int cros_ec_rpmsg_callback(struct rpmsg_device *rpdev, void *data,
167 int len, void *priv, u32 src)
168 {
169 struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev);
170 struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
171 struct cros_ec_rpmsg_response *resp;
172
173 if (!len) {
174 dev_warn(ec_dev->dev, "rpmsg received empty response");
175 return -EINVAL;
176 }
177
178 resp = data;
179 len -= offsetof(struct cros_ec_rpmsg_response, data);
180 if (resp->type == HOST_COMMAND_MARK) {
181 if (len > ec_dev->din_size) {
182 dev_warn(ec_dev->dev,
183 "received length %d > din_size %d, truncating",
184 len, ec_dev->din_size);
185 len = ec_dev->din_size;
186 }
187
188 memcpy(ec_dev->din, resp->data, len);
189 complete(&ec_rpmsg->xfer_ack);
190 } else if (resp->type == HOST_EVENT_MARK) {
191 /*
192 * If the host event is sent before cros_ec_register is
193 * finished, queue the host event.
194 */
195 if (ec_rpmsg->probe_done)
196 schedule_work(&ec_rpmsg->host_event_work);
197 else
198 ec_rpmsg->has_pending_host_event = true;
199 } else {
200 dev_warn(ec_dev->dev, "rpmsg received invalid type = %d",
201 resp->type);
202 return -EINVAL;
203 }
204
205 return 0;
206 }
207
208 static struct rpmsg_endpoint *
cros_ec_rpmsg_create_ept(struct rpmsg_device * rpdev)209 cros_ec_rpmsg_create_ept(struct rpmsg_device *rpdev)
210 {
211 struct rpmsg_channel_info chinfo = {};
212
213 strscpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE);
214 chinfo.src = rpdev->src;
215 chinfo.dst = RPMSG_ADDR_ANY;
216
217 return rpmsg_create_ept(rpdev, cros_ec_rpmsg_callback, NULL, chinfo);
218 }
219
cros_ec_rpmsg_probe(struct rpmsg_device * rpdev)220 static int cros_ec_rpmsg_probe(struct rpmsg_device *rpdev)
221 {
222 struct device *dev = &rpdev->dev;
223 struct cros_ec_rpmsg *ec_rpmsg;
224 struct cros_ec_device *ec_dev;
225 int ret;
226
227 ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
228 if (!ec_dev)
229 return -ENOMEM;
230
231 ec_rpmsg = devm_kzalloc(dev, sizeof(*ec_rpmsg), GFP_KERNEL);
232 if (!ec_rpmsg)
233 return -ENOMEM;
234
235 ec_dev->dev = dev;
236 ec_dev->priv = ec_rpmsg;
237 ec_dev->cmd_xfer = cros_ec_cmd_xfer_rpmsg;
238 ec_dev->pkt_xfer = cros_ec_pkt_xfer_rpmsg;
239 ec_dev->phys_name = dev_name(&rpdev->dev);
240 ec_dev->din_size = sizeof(struct ec_host_response) +
241 sizeof(struct ec_response_get_protocol_info);
242 ec_dev->dout_size = sizeof(struct ec_host_request);
243 dev_set_drvdata(dev, ec_dev);
244
245 ec_rpmsg->rpdev = rpdev;
246 init_completion(&ec_rpmsg->xfer_ack);
247 INIT_WORK(&ec_rpmsg->host_event_work,
248 cros_ec_rpmsg_host_event_function);
249
250 ec_rpmsg->ept = cros_ec_rpmsg_create_ept(rpdev);
251 if (!ec_rpmsg->ept)
252 return -ENOMEM;
253
254 ret = cros_ec_register(ec_dev);
255 if (ret < 0) {
256 rpmsg_destroy_ept(ec_rpmsg->ept);
257 cancel_work_sync(&ec_rpmsg->host_event_work);
258 return ret;
259 }
260
261 ec_rpmsg->probe_done = true;
262
263 if (ec_rpmsg->has_pending_host_event)
264 schedule_work(&ec_rpmsg->host_event_work);
265
266 return 0;
267 }
268
cros_ec_rpmsg_remove(struct rpmsg_device * rpdev)269 static void cros_ec_rpmsg_remove(struct rpmsg_device *rpdev)
270 {
271 struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev);
272 struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
273
274 cros_ec_unregister(ec_dev);
275 rpmsg_destroy_ept(ec_rpmsg->ept);
276 cancel_work_sync(&ec_rpmsg->host_event_work);
277 }
278
279 #ifdef CONFIG_PM_SLEEP
cros_ec_rpmsg_suspend(struct device * dev)280 static int cros_ec_rpmsg_suspend(struct device *dev)
281 {
282 struct cros_ec_device *ec_dev = dev_get_drvdata(dev);
283
284 return cros_ec_suspend(ec_dev);
285 }
286
cros_ec_rpmsg_resume(struct device * dev)287 static int cros_ec_rpmsg_resume(struct device *dev)
288 {
289 struct cros_ec_device *ec_dev = dev_get_drvdata(dev);
290
291 return cros_ec_resume(ec_dev);
292 }
293 #endif
294
295 static SIMPLE_DEV_PM_OPS(cros_ec_rpmsg_pm_ops, cros_ec_rpmsg_suspend,
296 cros_ec_rpmsg_resume);
297
298 static const struct of_device_id cros_ec_rpmsg_of_match[] = {
299 { .compatible = "google,cros-ec-rpmsg", },
300 { }
301 };
302 MODULE_DEVICE_TABLE(of, cros_ec_rpmsg_of_match);
303
304 static struct rpmsg_driver cros_ec_driver_rpmsg = {
305 .drv = {
306 .name = "cros-ec-rpmsg",
307 .of_match_table = cros_ec_rpmsg_of_match,
308 .pm = &cros_ec_rpmsg_pm_ops,
309 },
310 .probe = cros_ec_rpmsg_probe,
311 .remove = cros_ec_rpmsg_remove,
312 };
313
314 module_rpmsg_driver(cros_ec_driver_rpmsg);
315
316 MODULE_LICENSE("GPL v2");
317 MODULE_DESCRIPTION("ChromeOS EC multi function device (rpmsg)");
318