Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
usb: typec: ucsi: Implement ChromeOS UCSI driver
Implementation of a UCSI transport driver for ChromeOS.
This driver will be loaded if the ChromeOS EC implements a PPM.
Signed-off-by: Pavan Holla <pholla@chromium.org>
Co-developed-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
Co-developed-by: Łukasz Bartosik <ukaszb@chromium.org>
Signed-off-by: Łukasz Bartosik <ukaszb@chromium.org>
Link: https://lore.kernel.org/r/20241231131047.1757434-3-ukaszb@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
authored by
Pavan Holla
and committed by
Greg Kroah-Hartman
f1a22417
401d07d5
+358
+7
MAINTAINERS
+7
MAINTAINERS
···
5457
5457
S: Maintained
5458
5458
F: drivers/watchdog/cros_ec_wdt.c
5459
5459
5460
+
CHROMEOS UCSI DRIVER
5461
+
M: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
5462
+
M: Łukasz Bartosik <ukaszb@chromium.org>
5463
+
L: chrome-platform@lists.linux.dev
5464
+
S: Maintained
5465
+
F: drivers/usb/typec/ucsi/cros_ec_ucsi.c
5466
+
5460
5467
CHRONTEL CH7322 CEC DRIVER
5461
5468
M: Joe Tessler <jrt@google.com>
5462
5469
L: linux-media@vger.kernel.org
+13
drivers/usb/typec/ucsi/Kconfig
+13
drivers/usb/typec/ucsi/Kconfig
···
69
69
To compile the driver as a module, choose M here: the module will be
70
70
called ucsi_glink.
71
71
72
+
config CROS_EC_UCSI
73
+
tristate "UCSI Driver for ChromeOS EC"
74
+
depends on MFD_CROS_EC_DEV
75
+
depends on CROS_USBPD_NOTIFY
76
+
depends on !EXTCON_TCSS_CROS_EC
77
+
default MFD_CROS_EC_DEV
78
+
help
79
+
This driver enables UCSI support for a ChromeOS EC. The EC is
80
+
expected to implement a PPM.
81
+
82
+
To compile the driver as a module, choose M here: the module
83
+
will be called cros_ec_ucsi.
84
+
72
85
config UCSI_LENOVO_YOGA_C630
73
86
tristate "UCSI Interface Driver for Lenovo Yoga C630"
74
87
depends on EC_LENOVO_YOGA_C630
+1
drivers/usb/typec/ucsi/Makefile
+1
drivers/usb/typec/ucsi/Makefile
+337
drivers/usb/typec/ucsi/cros_ec_ucsi.c
+337
drivers/usb/typec/ucsi/cros_ec_ucsi.c
···
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
+
20
+
#include "ucsi.h"
21
+
22
+
/*
23
+
* Maximum size in bytes of a UCSI message between AP and EC
24
+
*/
25
+
#define MAX_EC_DATA_SIZE 256
26
+
27
+
/*
28
+
* Maximum time in milliseconds the cros_ec_ucsi driver
29
+
* will wait for a response to a command or and ack.
30
+
*/
31
+
#define WRITE_TMO_MS 5000
32
+
33
+
/* Number of times to attempt recovery from a write timeout before giving up. */
34
+
#define WRITE_TMO_CTR_MAX 5
35
+
36
+
struct cros_ucsi_data {
37
+
struct device *dev;
38
+
struct ucsi *ucsi;
39
+
40
+
struct cros_ec_device *ec;
41
+
struct notifier_block nb;
42
+
struct work_struct work;
43
+
struct delayed_work write_tmo;
44
+
int tmo_counter;
45
+
46
+
struct completion complete;
47
+
unsigned long flags;
48
+
};
49
+
50
+
static int cros_ucsi_read(struct ucsi *ucsi, unsigned int offset, void *val,
51
+
size_t val_len)
52
+
{
53
+
struct cros_ucsi_data *udata = ucsi_get_drvdata(ucsi);
54
+
struct ec_params_ucsi_ppm_get req = {
55
+
.offset = offset,
56
+
.size = val_len,
57
+
};
58
+
int ret;
59
+
60
+
if (val_len > MAX_EC_DATA_SIZE) {
61
+
dev_err(udata->dev, "Can't read %zu bytes. Too big.", val_len);
62
+
return -EINVAL;
63
+
}
64
+
65
+
ret = cros_ec_cmd(udata->ec, 0, EC_CMD_UCSI_PPM_GET,
66
+
&req, sizeof(req), val, val_len);
67
+
if (ret < 0) {
68
+
dev_warn(udata->dev, "Failed to send EC message UCSI_PPM_GET: error=%d", ret);
69
+
return ret;
70
+
}
71
+
return 0;
72
+
}
73
+
74
+
static int cros_ucsi_read_version(struct ucsi *ucsi, u16 *version)
75
+
{
76
+
return cros_ucsi_read(ucsi, UCSI_VERSION, version, sizeof(*version));
77
+
}
78
+
79
+
static int cros_ucsi_read_cci(struct ucsi *ucsi, u32 *cci)
80
+
{
81
+
return cros_ucsi_read(ucsi, UCSI_CCI, cci, sizeof(*cci));
82
+
}
83
+
84
+
static int cros_ucsi_read_message_in(struct ucsi *ucsi, void *val,
85
+
size_t val_len)
86
+
{
87
+
return cros_ucsi_read(ucsi, UCSI_MESSAGE_IN, val, val_len);
88
+
}
89
+
90
+
static int cros_ucsi_async_control(struct ucsi *ucsi, u64 cmd)
91
+
{
92
+
struct cros_ucsi_data *udata = ucsi_get_drvdata(ucsi);
93
+
u8 ec_buf[sizeof(struct ec_params_ucsi_ppm_set) + sizeof(cmd)];
94
+
struct ec_params_ucsi_ppm_set *req = (struct ec_params_ucsi_ppm_set *) ec_buf;
95
+
int ret;
96
+
97
+
req->offset = UCSI_CONTROL;
98
+
memcpy(req->data, &cmd, sizeof(cmd));
99
+
ret = cros_ec_cmd(udata->ec, 0, EC_CMD_UCSI_PPM_SET,
100
+
req, sizeof(ec_buf), NULL, 0);
101
+
if (ret < 0) {
102
+
dev_warn(udata->dev, "Failed to send EC message UCSI_PPM_SET: error=%d", ret);
103
+
return ret;
104
+
}
105
+
return 0;
106
+
}
107
+
108
+
static int cros_ucsi_sync_control(struct ucsi *ucsi, u64 cmd)
109
+
{
110
+
struct cros_ucsi_data *udata = ucsi_get_drvdata(ucsi);
111
+
int ret;
112
+
113
+
ret = ucsi_sync_control_common(ucsi, cmd);
114
+
switch (ret) {
115
+
case -EBUSY:
116
+
/* EC may return -EBUSY if CCI.busy is set.
117
+
* Convert this to a timeout.
118
+
*/
119
+
case -ETIMEDOUT:
120
+
/* Schedule recovery attempt when we timeout
121
+
* or tried to send a command while still busy.
122
+
*/
123
+
cancel_delayed_work_sync(&udata->write_tmo);
124
+
schedule_delayed_work(&udata->write_tmo,
125
+
msecs_to_jiffies(WRITE_TMO_MS));
126
+
break;
127
+
case 0:
128
+
/* Successful write. Cancel any pending recovery work. */
129
+
cancel_delayed_work_sync(&udata->write_tmo);
130
+
break;
131
+
}
132
+
133
+
return ret;
134
+
}
135
+
136
+
struct ucsi_operations cros_ucsi_ops = {
137
+
.read_version = cros_ucsi_read_version,
138
+
.read_cci = cros_ucsi_read_cci,
139
+
.read_message_in = cros_ucsi_read_message_in,
140
+
.async_control = cros_ucsi_async_control,
141
+
.sync_control = cros_ucsi_sync_control,
142
+
};
143
+
144
+
static void cros_ucsi_work(struct work_struct *work)
145
+
{
146
+
struct cros_ucsi_data *udata = container_of(work, struct cros_ucsi_data, work);
147
+
u32 cci;
148
+
149
+
if (cros_ucsi_read_cci(udata->ucsi, &cci))
150
+
return;
151
+
152
+
ucsi_notify_common(udata->ucsi, cci);
153
+
}
154
+
155
+
static void cros_ucsi_write_timeout(struct work_struct *work)
156
+
{
157
+
struct cros_ucsi_data *udata =
158
+
container_of(work, struct cros_ucsi_data, write_tmo.work);
159
+
u32 cci;
160
+
u64 cmd;
161
+
162
+
if (cros_ucsi_read(udata->ucsi, UCSI_CCI, &cci, sizeof(cci))) {
163
+
dev_err(udata->dev,
164
+
"Reading CCI failed; no write timeout recovery possible.");
165
+
return;
166
+
}
167
+
168
+
if (cci & UCSI_CCI_BUSY) {
169
+
udata->tmo_counter++;
170
+
171
+
if (udata->tmo_counter <= WRITE_TMO_CTR_MAX)
172
+
schedule_delayed_work(&udata->write_tmo,
173
+
msecs_to_jiffies(WRITE_TMO_MS));
174
+
else
175
+
dev_err(udata->dev,
176
+
"PPM unresponsive - too many write timeouts.");
177
+
178
+
return;
179
+
}
180
+
181
+
/* No longer busy means we can reset our timeout counter. */
182
+
udata->tmo_counter = 0;
183
+
184
+
/* Need to ack previous command which may have timed out. */
185
+
if (cci & UCSI_CCI_COMMAND_COMPLETE) {
186
+
cmd = UCSI_ACK_CC_CI | UCSI_ACK_COMMAND_COMPLETE;
187
+
cros_ucsi_async_control(udata->ucsi, cmd);
188
+
189
+
/* Check again after a few seconds that the system has
190
+
* recovered to make sure our async write above was successful.
191
+
*/
192
+
schedule_delayed_work(&udata->write_tmo,
193
+
msecs_to_jiffies(WRITE_TMO_MS));
194
+
return;
195
+
}
196
+
197
+
/* We recovered from a previous timeout. Treat this as a recovery from
198
+
* suspend and call resume.
199
+
*/
200
+
ucsi_resume(udata->ucsi);
201
+
}
202
+
203
+
static int cros_ucsi_event(struct notifier_block *nb,
204
+
unsigned long host_event, void *_notify)
205
+
{
206
+
struct cros_ucsi_data *udata = container_of(nb, struct cros_ucsi_data, nb);
207
+
208
+
if (!(host_event & PD_EVENT_PPM))
209
+
return NOTIFY_OK;
210
+
211
+
dev_dbg(udata->dev, "UCSI notification received");
212
+
flush_work(&udata->work);
213
+
schedule_work(&udata->work);
214
+
215
+
return NOTIFY_OK;
216
+
}
217
+
218
+
static void cros_ucsi_destroy(struct cros_ucsi_data *udata)
219
+
{
220
+
cros_usbpd_unregister_notify(&udata->nb);
221
+
cancel_delayed_work_sync(&udata->write_tmo);
222
+
cancel_work_sync(&udata->work);
223
+
ucsi_destroy(udata->ucsi);
224
+
}
225
+
226
+
static int cros_ucsi_probe(struct platform_device *pdev)
227
+
{
228
+
struct device *dev = &pdev->dev;
229
+
struct cros_ec_dev *ec_data = dev_get_drvdata(dev->parent);
230
+
struct cros_ucsi_data *udata;
231
+
int ret;
232
+
233
+
udata = devm_kzalloc(dev, sizeof(*udata), GFP_KERNEL);
234
+
if (!udata)
235
+
return -ENOMEM;
236
+
237
+
udata->dev = dev;
238
+
239
+
udata->ec = ec_data->ec_dev;
240
+
if (!udata->ec) {
241
+
dev_err(dev, "couldn't find parent EC device");
242
+
return -ENODEV;
243
+
}
244
+
245
+
platform_set_drvdata(pdev, udata);
246
+
247
+
INIT_WORK(&udata->work, cros_ucsi_work);
248
+
INIT_DELAYED_WORK(&udata->write_tmo, cros_ucsi_write_timeout);
249
+
init_completion(&udata->complete);
250
+
251
+
udata->ucsi = ucsi_create(dev, &cros_ucsi_ops);
252
+
if (IS_ERR(udata->ucsi)) {
253
+
dev_err(dev, "failed to allocate UCSI instance");
254
+
return PTR_ERR(udata->ucsi);
255
+
}
256
+
257
+
ucsi_set_drvdata(udata->ucsi, udata);
258
+
259
+
udata->nb.notifier_call = cros_ucsi_event;
260
+
ret = cros_usbpd_register_notify(&udata->nb);
261
+
if (ret) {
262
+
dev_err(dev, "failed to register notifier: error=%d", ret);
263
+
ucsi_destroy(udata->ucsi);
264
+
return ret;
265
+
}
266
+
267
+
ret = ucsi_register(udata->ucsi);
268
+
if (ret) {
269
+
dev_err(dev, "failed to register UCSI: error=%d", ret);
270
+
cros_ucsi_destroy(udata);
271
+
return ret;
272
+
}
273
+
274
+
return 0;
275
+
}
276
+
277
+
static void cros_ucsi_remove(struct platform_device *dev)
278
+
{
279
+
struct cros_ucsi_data *udata = platform_get_drvdata(dev);
280
+
281
+
ucsi_unregister(udata->ucsi);
282
+
cros_ucsi_destroy(udata);
283
+
}
284
+
285
+
static int __maybe_unused cros_ucsi_suspend(struct device *dev)
286
+
{
287
+
struct cros_ucsi_data *udata = dev_get_drvdata(dev);
288
+
289
+
cancel_delayed_work_sync(&udata->write_tmo);
290
+
cancel_work_sync(&udata->work);
291
+
292
+
return 0;
293
+
}
294
+
295
+
static void __maybe_unused cros_ucsi_complete(struct device *dev)
296
+
{
297
+
struct cros_ucsi_data *udata = dev_get_drvdata(dev);
298
+
299
+
ucsi_resume(udata->ucsi);
300
+
}
301
+
302
+
/*
303
+
* UCSI protocol is also used on ChromeOS platforms which reply on
304
+
* cros_ec_lpc.c driver for communication with embedded controller (EC).
305
+
* On such platforms communication with the EC is not available until
306
+
* the .complete() callback of the cros_ec_lpc driver is executed.
307
+
* For this reason we delay ucsi_resume() until the .complete() stage
308
+
* otherwise UCSI SET_NOTIFICATION_ENABLE command will fail and we won't
309
+
* receive any UCSI notifications from the EC where PPM is implemented.
310
+
*/
311
+
static const struct dev_pm_ops cros_ucsi_pm_ops = {
312
+
#ifdef CONFIG_PM_SLEEP
313
+
.suspend = cros_ucsi_suspend,
314
+
.complete = cros_ucsi_complete,
315
+
#endif
316
+
};
317
+
318
+
static const struct platform_device_id cros_ucsi_id[] = {
319
+
{ KBUILD_MODNAME, 0 },
320
+
{}
321
+
};
322
+
MODULE_DEVICE_TABLE(platform, cros_ucsi_id);
323
+
324
+
static struct platform_driver cros_ucsi_driver = {
325
+
.driver = {
326
+
.name = KBUILD_MODNAME,
327
+
.pm = &cros_ucsi_pm_ops,
328
+
},
329
+
.id_table = cros_ucsi_id,
330
+
.probe = cros_ucsi_probe,
331
+
.remove = cros_ucsi_remove,
332
+
};
333
+
334
+
module_platform_driver(cros_ucsi_driver);
335
+
336
+
MODULE_LICENSE("GPL");
337
+
MODULE_DESCRIPTION("UCSI driver for ChromeOS EC");