1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * UCSI driver for ChromeOS EC
4 *
5 * Copyright 2024 Google LLC.
6 */
7
8 #include <linux/container_of.h>
9 #include <linux/dev_printk.h>
10 #include <linux/jiffies.h>
11 #include <linux/mod_devicetable.h>
12 #include <linux/module.h>
13 #include <linux/platform_data/cros_ec_commands.h>
14 #include <linux/platform_data/cros_usbpd_notify.h>
15 #include <linux/platform_data/cros_ec_proto.h>
16 #include <linux/platform_device.h>
17 #include <linux/slab.h>
18 #include <linux/wait.h>
19 #include <linux/usb/typec_altmode.h>
20
21 #include "ucsi.h"
22
23 /*
24 * Maximum size in bytes of a UCSI message between AP and EC
25 */
26 #define MAX_EC_DATA_SIZE 256
27
28 /*
29 * Maximum time in milliseconds the cros_ec_ucsi driver
30 * will wait for a response to a command or and ack.
31 */
32 #define WRITE_TMO_MS 5000
33
34 /* Number of times to attempt recovery from a write timeout before giving up. */
35 #define WRITE_TMO_CTR_MAX 5
36
37 /* Delay between mode entry/exit attempts, ms */
38 static const unsigned int mode_selection_delay = 1000;
39 /* Timeout for a mode entry attempt, ms */
40 static const unsigned int mode_selection_timeout = 4000;
41
42 struct cros_ucsi_data {
43 struct device *dev;
44 struct ucsi *ucsi;
45
46 struct cros_ec_device *ec;
47 struct notifier_block nb;
48 struct work_struct work;
49 struct delayed_work write_tmo;
50 int tmo_counter;
51
52 struct completion complete;
53 unsigned long flags;
54 };
55
cros_ucsi_read(struct ucsi * ucsi,unsigned int offset,void * val,size_t val_len)56 static int cros_ucsi_read(struct ucsi *ucsi, unsigned int offset, void *val,
57 size_t val_len)
58 {
59 struct cros_ucsi_data *udata = ucsi_get_drvdata(ucsi);
60 struct ec_params_ucsi_ppm_get req = {
61 .offset = offset,
62 .size = val_len,
63 };
64 int ret;
65
66 if (val_len > MAX_EC_DATA_SIZE) {
67 dev_err(udata->dev, "Can't read %zu bytes. Too big.\n", val_len);
68 return -EINVAL;
69 }
70
71 ret = cros_ec_cmd(udata->ec, 0, EC_CMD_UCSI_PPM_GET,
72 &req, sizeof(req), val, val_len);
73 if (ret < 0) {
74 dev_warn(udata->dev, "Failed to send EC message UCSI_PPM_GET: error=%d\n", ret);
75 return ret;
76 }
77 return 0;
78 }
79
cros_ucsi_read_version(struct ucsi * ucsi,u16 * version)80 static int cros_ucsi_read_version(struct ucsi *ucsi, u16 *version)
81 {
82 return cros_ucsi_read(ucsi, UCSI_VERSION, version, sizeof(*version));
83 }
84
cros_ucsi_read_cci(struct ucsi * ucsi,u32 * cci)85 static int cros_ucsi_read_cci(struct ucsi *ucsi, u32 *cci)
86 {
87 return cros_ucsi_read(ucsi, UCSI_CCI, cci, sizeof(*cci));
88 }
89
cros_ucsi_read_message_in(struct ucsi * ucsi,void * val,size_t val_len)90 static int cros_ucsi_read_message_in(struct ucsi *ucsi, void *val,
91 size_t val_len)
92 {
93 return cros_ucsi_read(ucsi, UCSI_MESSAGE_IN, val, val_len);
94 }
95
cros_ucsi_async_control(struct ucsi * ucsi,u64 cmd)96 static int cros_ucsi_async_control(struct ucsi *ucsi, u64 cmd)
97 {
98 struct cros_ucsi_data *udata = ucsi_get_drvdata(ucsi);
99 u8 ec_buf[sizeof(struct ec_params_ucsi_ppm_set) + sizeof(cmd)];
100 struct ec_params_ucsi_ppm_set *req = (struct ec_params_ucsi_ppm_set *) ec_buf;
101 int ret;
102
103 req->offset = UCSI_CONTROL;
104 memcpy(req->data, &cmd, sizeof(cmd));
105 ret = cros_ec_cmd(udata->ec, 0, EC_CMD_UCSI_PPM_SET,
106 req, sizeof(ec_buf), NULL, 0);
107 if (ret < 0) {
108 dev_warn(udata->dev, "Failed to send EC message UCSI_PPM_SET: error=%d\n", ret);
109 return ret;
110 }
111 return 0;
112 }
113
cros_ucsi_sync_control(struct ucsi * ucsi,u64 cmd,u32 * cci,void * data,size_t size)114 static int cros_ucsi_sync_control(struct ucsi *ucsi, u64 cmd, u32 *cci,
115 void *data, size_t size)
116 {
117 struct cros_ucsi_data *udata = ucsi_get_drvdata(ucsi);
118 int ret;
119
120 ret = ucsi_sync_control_common(ucsi, cmd, cci, data, size);
121 switch (ret) {
122 case -EBUSY:
123 /* EC may return -EBUSY if CCI.busy is set.
124 * Convert this to a timeout.
125 */
126 case -ETIMEDOUT:
127 /* Schedule recovery attempt when we timeout
128 * or tried to send a command while still busy.
129 */
130 cancel_delayed_work_sync(&udata->write_tmo);
131 schedule_delayed_work(&udata->write_tmo,
132 msecs_to_jiffies(WRITE_TMO_MS));
133 break;
134 case 0:
135 /* Successful write. Cancel any pending recovery work. */
136 cancel_delayed_work_sync(&udata->write_tmo);
137 break;
138 }
139
140 return ret;
141 }
142
cros_ucsi_add_partner_altmodes(struct ucsi_connector * con)143 static void cros_ucsi_add_partner_altmodes(struct ucsi_connector *con)
144 {
145 if (!con->typec_cap.no_mode_control)
146 typec_mode_selection_start(con->partner,
147 mode_selection_delay,
148 mode_selection_timeout);
149 }
150
cros_ucsi_remove_partner_altmodes(struct ucsi_connector * con)151 static void cros_ucsi_remove_partner_altmodes(struct ucsi_connector *con)
152 {
153 if (!con->typec_cap.no_mode_control)
154 typec_mode_selection_delete(con->partner);
155 }
156
157 static const struct ucsi_operations cros_ucsi_ops = {
158 .read_version = cros_ucsi_read_version,
159 .read_cci = cros_ucsi_read_cci,
160 .poll_cci = cros_ucsi_read_cci,
161 .read_message_in = cros_ucsi_read_message_in,
162 .async_control = cros_ucsi_async_control,
163 .sync_control = cros_ucsi_sync_control,
164 .add_partner_altmodes = cros_ucsi_add_partner_altmodes,
165 .remove_partner_altmodes = cros_ucsi_remove_partner_altmodes,
166 };
167
cros_ucsi_work(struct work_struct * work)168 static void cros_ucsi_work(struct work_struct *work)
169 {
170 struct cros_ucsi_data *udata = container_of(work, struct cros_ucsi_data, work);
171 u32 cci;
172
173 if (cros_ucsi_read_cci(udata->ucsi, &cci))
174 return;
175
176 ucsi_notify_common(udata->ucsi, cci);
177 }
178
cros_ucsi_write_timeout(struct work_struct * work)179 static void cros_ucsi_write_timeout(struct work_struct *work)
180 {
181 struct cros_ucsi_data *udata =
182 container_of(work, struct cros_ucsi_data, write_tmo.work);
183 u32 cci;
184 u64 cmd;
185
186 if (cros_ucsi_read(udata->ucsi, UCSI_CCI, &cci, sizeof(cci))) {
187 dev_err(udata->dev,
188 "Reading CCI failed; no write timeout recovery possible.\n");
189 return;
190 }
191
192 if (cci & UCSI_CCI_BUSY) {
193 udata->tmo_counter++;
194
195 if (udata->tmo_counter <= WRITE_TMO_CTR_MAX)
196 schedule_delayed_work(&udata->write_tmo,
197 msecs_to_jiffies(WRITE_TMO_MS));
198 else
199 dev_err(udata->dev,
200 "PPM unresponsive - too many write timeouts.\n");
201
202 return;
203 }
204
205 /* No longer busy means we can reset our timeout counter. */
206 udata->tmo_counter = 0;
207
208 /* Need to ack previous command which may have timed out. */
209 if (cci & UCSI_CCI_COMMAND_COMPLETE) {
210 cmd = UCSI_ACK_CC_CI | UCSI_ACK_COMMAND_COMPLETE;
211 cros_ucsi_async_control(udata->ucsi, cmd);
212
213 /* Check again after a few seconds that the system has
214 * recovered to make sure our async write above was successful.
215 */
216 schedule_delayed_work(&udata->write_tmo,
217 msecs_to_jiffies(WRITE_TMO_MS));
218 return;
219 }
220
221 /* We recovered from a previous timeout. Treat this as a recovery from
222 * suspend and call resume.
223 */
224 ucsi_resume(udata->ucsi);
225 }
226
cros_ucsi_event(struct notifier_block * nb,unsigned long host_event,void * _notify)227 static int cros_ucsi_event(struct notifier_block *nb,
228 unsigned long host_event, void *_notify)
229 {
230 struct cros_ucsi_data *udata = container_of(nb, struct cros_ucsi_data, nb);
231
232 if (host_event & PD_EVENT_INIT) {
233 /* Late init event received from ChromeOS EC. Treat this as a
234 * system resume to re-enable communication with the PPM.
235 */
236 dev_dbg(udata->dev, "Late PD init received\n");
237 ucsi_resume(udata->ucsi);
238 }
239
240 if (host_event & PD_EVENT_PPM) {
241 dev_dbg(udata->dev, "UCSI notification received\n");
242 flush_work(&udata->work);
243 schedule_work(&udata->work);
244 }
245
246 return NOTIFY_OK;
247 }
248
cros_ucsi_destroy(struct cros_ucsi_data * udata)249 static void cros_ucsi_destroy(struct cros_ucsi_data *udata)
250 {
251 cros_usbpd_unregister_notify(&udata->nb);
252 cancel_delayed_work_sync(&udata->write_tmo);
253 cancel_work_sync(&udata->work);
254 ucsi_destroy(udata->ucsi);
255 }
256
cros_ucsi_probe(struct platform_device * pdev)257 static int cros_ucsi_probe(struct platform_device *pdev)
258 {
259 struct device *dev = &pdev->dev;
260 struct cros_ec_dev *ec_data = dev_get_drvdata(dev->parent);
261 struct cros_ucsi_data *udata;
262 int ret;
263
264 udata = devm_kzalloc(dev, sizeof(*udata), GFP_KERNEL);
265 if (!udata)
266 return -ENOMEM;
267
268 udata->dev = dev;
269
270 udata->ec = ec_data->ec_dev;
271 if (!udata->ec)
272 return dev_err_probe(dev, -ENODEV, "couldn't find parent EC device\n");
273
274 platform_set_drvdata(pdev, udata);
275
276 INIT_WORK(&udata->work, cros_ucsi_work);
277 INIT_DELAYED_WORK(&udata->write_tmo, cros_ucsi_write_timeout);
278 init_completion(&udata->complete);
279
280 udata->ucsi = ucsi_create(dev, &cros_ucsi_ops);
281 if (IS_ERR(udata->ucsi))
282 return dev_err_probe(dev, PTR_ERR(udata->ucsi), "failed to allocate UCSI instance\n");
283
284 ucsi_set_drvdata(udata->ucsi, udata);
285
286 udata->nb.notifier_call = cros_ucsi_event;
287 ret = cros_usbpd_register_notify(&udata->nb);
288 if (ret) {
289 dev_err_probe(dev, ret, "failed to register notifier\n");
290 ucsi_destroy(udata->ucsi);
291 return ret;
292 }
293
294 ret = ucsi_register(udata->ucsi);
295 if (ret) {
296 dev_err_probe(dev, ret, "failed to register UCSI\n");
297 cros_ucsi_destroy(udata);
298 return ret;
299 }
300
301 return 0;
302 }
303
cros_ucsi_remove(struct platform_device * dev)304 static void cros_ucsi_remove(struct platform_device *dev)
305 {
306 struct cros_ucsi_data *udata = platform_get_drvdata(dev);
307
308 ucsi_unregister(udata->ucsi);
309 cros_ucsi_destroy(udata);
310 }
311
cros_ucsi_suspend(struct device * dev)312 static int __maybe_unused cros_ucsi_suspend(struct device *dev)
313 {
314 struct cros_ucsi_data *udata = dev_get_drvdata(dev);
315
316 cancel_delayed_work_sync(&udata->write_tmo);
317 cancel_work_sync(&udata->work);
318
319 return 0;
320 }
321
cros_ucsi_complete(struct device * dev)322 static void __maybe_unused cros_ucsi_complete(struct device *dev)
323 {
324 struct cros_ucsi_data *udata = dev_get_drvdata(dev);
325
326 ucsi_resume(udata->ucsi);
327 }
328
329 /*
330 * UCSI protocol is also used on ChromeOS platforms which reply on
331 * cros_ec_lpc.c driver for communication with embedded controller (EC).
332 * On such platforms communication with the EC is not available until
333 * the .complete() callback of the cros_ec_lpc driver is executed.
334 * For this reason we delay ucsi_resume() until the .complete() stage
335 * otherwise UCSI SET_NOTIFICATION_ENABLE command will fail and we won't
336 * receive any UCSI notifications from the EC where PPM is implemented.
337 */
338 static const struct dev_pm_ops cros_ucsi_pm_ops = {
339 #ifdef CONFIG_PM_SLEEP
340 .suspend = cros_ucsi_suspend,
341 .complete = cros_ucsi_complete,
342 #endif
343 };
344
345 static const struct platform_device_id cros_ucsi_id[] = {
346 { KBUILD_MODNAME, 0 },
347 {}
348 };
349 MODULE_DEVICE_TABLE(platform, cros_ucsi_id);
350
351 static struct platform_driver cros_ucsi_driver = {
352 .driver = {
353 .name = KBUILD_MODNAME,
354 .pm = &cros_ucsi_pm_ops,
355 },
356 .id_table = cros_ucsi_id,
357 .probe = cros_ucsi_probe,
358 .remove = cros_ucsi_remove,
359 };
360
361 module_platform_driver(cros_ucsi_driver);
362
363 MODULE_LICENSE("GPL");
364 MODULE_DESCRIPTION("UCSI driver for ChromeOS EC");
365