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 dev_dbg(ec_dev->dev, "prepared, len=%d\n", len);
93
94 reinit_completion(&ec_rpmsg->xfer_ack);
95 ret = rpmsg_send(ec_rpmsg->ept, ec_dev->dout, len);
96 if (ret) {
97 dev_err(ec_dev->dev, "rpmsg send failed\n");
98 return ret;
99 }
100
101 timeout = msecs_to_jiffies(EC_MSG_TIMEOUT_MS);
102 ret = wait_for_completion_timeout(&ec_rpmsg->xfer_ack, timeout);
103 if (!ret) {
104 dev_err(ec_dev->dev, "rpmsg send timeout\n");
105 return -EIO;
106 }
107
108 /* check response error code */
109 response = (struct ec_host_response *)ec_dev->din;
110 ec_msg->result = response->result;
111
112 ret = cros_ec_check_result(ec_dev, ec_msg);
113 if (ret)
114 goto exit;
115
116 if (response->data_len > ec_msg->insize) {
117 dev_err(ec_dev->dev, "packet too long (%d bytes, expected %d)",
118 response->data_len, ec_msg->insize);
119 ret = -EMSGSIZE;
120 goto exit;
121 }
122
123 /* copy response packet payload and compute checksum */
124 memcpy(ec_msg->data, ec_dev->din + sizeof(*response),
125 response->data_len);
126
127 sum = 0;
128 for (i = 0; i < sizeof(*response) + response->data_len; i++)
129 sum += ec_dev->din[i];
130
131 if (sum) {
132 dev_err(ec_dev->dev, "bad packet checksum, calculated %x\n",
133 sum);
134 ret = -EBADMSG;
135 goto exit;
136 }
137
138 ret = response->data_len;
139 exit:
140 if (ec_msg->command == EC_CMD_REBOOT_EC)
141 msleep(EC_REBOOT_DELAY_MS);
142
143 return ret;
144 }
145
146 static void
cros_ec_rpmsg_host_event_function(struct work_struct * host_event_work)147 cros_ec_rpmsg_host_event_function(struct work_struct *host_event_work)
148 {
149 struct cros_ec_rpmsg *ec_rpmsg = container_of(host_event_work,
150 struct cros_ec_rpmsg,
151 host_event_work);
152
153 cros_ec_irq_thread(0, dev_get_drvdata(&ec_rpmsg->rpdev->dev));
154 }
155
cros_ec_rpmsg_callback(struct rpmsg_device * rpdev,void * data,int len,void * priv,u32 src)156 static int cros_ec_rpmsg_callback(struct rpmsg_device *rpdev, void *data,
157 int len, void *priv, u32 src)
158 {
159 struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev);
160 struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
161 struct cros_ec_rpmsg_response *resp;
162
163 if (!len) {
164 dev_warn(ec_dev->dev, "rpmsg received empty response");
165 return -EINVAL;
166 }
167
168 resp = data;
169 len -= offsetof(struct cros_ec_rpmsg_response, data);
170 if (resp->type == HOST_COMMAND_MARK) {
171 if (len > ec_dev->din_size) {
172 dev_warn(ec_dev->dev,
173 "received length %d > din_size %d, truncating",
174 len, ec_dev->din_size);
175 len = ec_dev->din_size;
176 }
177
178 memcpy(ec_dev->din, resp->data, len);
179 complete(&ec_rpmsg->xfer_ack);
180 } else if (resp->type == HOST_EVENT_MARK) {
181 /*
182 * If the host event is sent before cros_ec_register is
183 * finished, queue the host event.
184 */
185 if (ec_rpmsg->probe_done)
186 schedule_work(&ec_rpmsg->host_event_work);
187 else
188 ec_rpmsg->has_pending_host_event = true;
189 } else {
190 dev_warn(ec_dev->dev, "rpmsg received invalid type = %d",
191 resp->type);
192 return -EINVAL;
193 }
194
195 return 0;
196 }
197
198 static struct rpmsg_endpoint *
cros_ec_rpmsg_create_ept(struct rpmsg_device * rpdev)199 cros_ec_rpmsg_create_ept(struct rpmsg_device *rpdev)
200 {
201 struct rpmsg_channel_info chinfo = {};
202
203 strscpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE);
204 chinfo.src = rpdev->src;
205 chinfo.dst = RPMSG_ADDR_ANY;
206
207 return rpmsg_create_ept(rpdev, cros_ec_rpmsg_callback, NULL, chinfo);
208 }
209
cros_ec_rpmsg_probe(struct rpmsg_device * rpdev)210 static int cros_ec_rpmsg_probe(struct rpmsg_device *rpdev)
211 {
212 struct device *dev = &rpdev->dev;
213 struct cros_ec_rpmsg *ec_rpmsg;
214 struct cros_ec_device *ec_dev;
215 int ret;
216
217 ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
218 if (!ec_dev)
219 return -ENOMEM;
220
221 ec_rpmsg = devm_kzalloc(dev, sizeof(*ec_rpmsg), GFP_KERNEL);
222 if (!ec_rpmsg)
223 return -ENOMEM;
224
225 ec_dev->dev = dev;
226 ec_dev->priv = ec_rpmsg;
227 ec_dev->cmd_xfer = cros_ec_cmd_xfer_rpmsg;
228 ec_dev->pkt_xfer = cros_ec_pkt_xfer_rpmsg;
229 ec_dev->phys_name = dev_name(&rpdev->dev);
230 ec_dev->din_size = sizeof(struct ec_host_response) +
231 sizeof(struct ec_response_get_protocol_info);
232 ec_dev->dout_size = sizeof(struct ec_host_request);
233 dev_set_drvdata(dev, ec_dev);
234
235 ec_rpmsg->rpdev = rpdev;
236 init_completion(&ec_rpmsg->xfer_ack);
237 INIT_WORK(&ec_rpmsg->host_event_work,
238 cros_ec_rpmsg_host_event_function);
239
240 ec_rpmsg->ept = cros_ec_rpmsg_create_ept(rpdev);
241 if (!ec_rpmsg->ept)
242 return -ENOMEM;
243
244 ret = cros_ec_register(ec_dev);
245 if (ret < 0) {
246 rpmsg_destroy_ept(ec_rpmsg->ept);
247 cancel_work_sync(&ec_rpmsg->host_event_work);
248 return ret;
249 }
250
251 ec_rpmsg->probe_done = true;
252
253 if (ec_rpmsg->has_pending_host_event)
254 schedule_work(&ec_rpmsg->host_event_work);
255
256 return 0;
257 }
258
cros_ec_rpmsg_remove(struct rpmsg_device * rpdev)259 static void cros_ec_rpmsg_remove(struct rpmsg_device *rpdev)
260 {
261 struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev);
262 struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
263
264 cros_ec_unregister(ec_dev);
265 rpmsg_destroy_ept(ec_rpmsg->ept);
266 cancel_work_sync(&ec_rpmsg->host_event_work);
267 }
268
269 #ifdef CONFIG_PM_SLEEP
cros_ec_rpmsg_suspend(struct device * dev)270 static int cros_ec_rpmsg_suspend(struct device *dev)
271 {
272 struct cros_ec_device *ec_dev = dev_get_drvdata(dev);
273
274 return cros_ec_suspend(ec_dev);
275 }
276
cros_ec_rpmsg_resume(struct device * dev)277 static int cros_ec_rpmsg_resume(struct device *dev)
278 {
279 struct cros_ec_device *ec_dev = dev_get_drvdata(dev);
280
281 return cros_ec_resume(ec_dev);
282 }
283 #endif
284
285 static SIMPLE_DEV_PM_OPS(cros_ec_rpmsg_pm_ops, cros_ec_rpmsg_suspend,
286 cros_ec_rpmsg_resume);
287
288 static const struct of_device_id cros_ec_rpmsg_of_match[] = {
289 { .compatible = "google,cros-ec-rpmsg", },
290 { }
291 };
292 MODULE_DEVICE_TABLE(of, cros_ec_rpmsg_of_match);
293
294 static struct rpmsg_driver cros_ec_driver_rpmsg = {
295 .drv = {
296 .name = "cros-ec-rpmsg",
297 .of_match_table = cros_ec_rpmsg_of_match,
298 .pm = &cros_ec_rpmsg_pm_ops,
299 },
300 .probe = cros_ec_rpmsg_probe,
301 .remove = cros_ec_rpmsg_remove,
302 };
303
304 module_rpmsg_driver(cros_ec_driver_rpmsg);
305
306 MODULE_LICENSE("GPL v2");
307 MODULE_DESCRIPTION("ChromeOS EC multi function device (rpmsg)");
308