1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2022 Microchip.
4 */
5
6#include <linux/device.h>
7#include <linux/kernel.h>
8#include <linux/module.h>
9#include <linux/rtc.h>
10#include <linux/tee_drv.h>
11
12#define RTC_INFO_VERSION	0x1
13
14#define TA_CMD_RTC_GET_INFO		0x0
15#define TA_CMD_RTC_GET_TIME		0x1
16#define TA_CMD_RTC_SET_TIME		0x2
17#define TA_CMD_RTC_GET_OFFSET		0x3
18#define TA_CMD_RTC_SET_OFFSET		0x4
19
20#define TA_RTC_FEATURE_CORRECTION	BIT(0)
21
22struct optee_rtc_time {
23	u32 tm_sec;
24	u32 tm_min;
25	u32 tm_hour;
26	u32 tm_mday;
27	u32 tm_mon;
28	u32 tm_year;
29	u32 tm_wday;
30};
31
32struct optee_rtc_info {
33	u64 version;
34	u64 features;
35	struct optee_rtc_time range_min;
36	struct optee_rtc_time range_max;
37};
38
39/**
40 * struct optee_rtc - OP-TEE RTC private data
41 * @dev:		OP-TEE based RTC device.
42 * @ctx:		OP-TEE context handler.
43 * @session_id:		RTC TA session identifier.
44 * @shm:		Memory pool shared with RTC device.
45 * @features:		Bitfield of RTC features
46 */
47struct optee_rtc {
48	struct device *dev;
49	struct tee_context *ctx;
50	u32 session_id;
51	struct tee_shm *shm;
52	u64 features;
53};
54
55static int optee_rtc_readtime(struct device *dev, struct rtc_time *tm)
56{
57	struct optee_rtc *priv = dev_get_drvdata(dev);
58	struct tee_ioctl_invoke_arg inv_arg = {0};
59	struct optee_rtc_time *optee_tm;
60	struct tee_param param[4] = {0};
61	int ret;
62
63	inv_arg.func = TA_CMD_RTC_GET_TIME;
64	inv_arg.session = priv->session_id;
65	inv_arg.num_params = 4;
66
67	/* Fill invoke cmd params */
68	param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT;
69	param[0].u.memref.shm = priv->shm;
70	param[0].u.memref.size = sizeof(struct optee_rtc_time);
71
72	ret = tee_client_invoke_func(priv->ctx, &inv_arg, param);
73	if (ret < 0 || inv_arg.ret != 0)
74		return ret ? ret : -EPROTO;
75
76	optee_tm = tee_shm_get_va(priv->shm, 0);
77	if (IS_ERR(optee_tm))
78		return PTR_ERR(optee_tm);
79
80	if (param[0].u.memref.size != sizeof(*optee_tm))
81		return -EPROTO;
82
83	tm->tm_sec = optee_tm->tm_sec;
84	tm->tm_min = optee_tm->tm_min;
85	tm->tm_hour = optee_tm->tm_hour;
86	tm->tm_mday = optee_tm->tm_mday;
87	tm->tm_mon = optee_tm->tm_mon;
88	tm->tm_year = optee_tm->tm_year - 1900;
89	tm->tm_wday = optee_tm->tm_wday;
90	tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
91
92	return 0;
93}
94
95static int optee_rtc_settime(struct device *dev, struct rtc_time *tm)
96{
97	struct optee_rtc *priv = dev_get_drvdata(dev);
98	struct tee_ioctl_invoke_arg inv_arg = {0};
99	struct tee_param param[4] = {0};
100	struct optee_rtc_time optee_tm;
101	void *rtc_data;
102	int ret;
103
104	optee_tm.tm_sec = tm->tm_sec;
105	optee_tm.tm_min = tm->tm_min;
106	optee_tm.tm_hour = tm->tm_hour;
107	optee_tm.tm_mday = tm->tm_mday;
108	optee_tm.tm_mon = tm->tm_mon;
109	optee_tm.tm_year = tm->tm_year + 1900;
110	optee_tm.tm_wday = tm->tm_wday;
111
112	inv_arg.func = TA_CMD_RTC_SET_TIME;
113	inv_arg.session = priv->session_id;
114	inv_arg.num_params = 4;
115
116	param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT;
117	param[0].u.memref.shm = priv->shm;
118	param[0].u.memref.size = sizeof(struct optee_rtc_time);
119
120	rtc_data = tee_shm_get_va(priv->shm, 0);
121	if (IS_ERR(rtc_data))
122		return PTR_ERR(rtc_data);
123
124	memcpy(rtc_data, &optee_tm, sizeof(struct optee_rtc_time));
125
126	ret = tee_client_invoke_func(priv->ctx, &inv_arg, param);
127	if (ret < 0 || inv_arg.ret != 0)
128		return ret ? ret : -EPROTO;
129
130	return 0;
131}
132
133static int optee_rtc_readoffset(struct device *dev, long *offset)
134{
135	struct optee_rtc *priv = dev_get_drvdata(dev);
136	struct tee_ioctl_invoke_arg inv_arg = {0};
137	struct tee_param param[4] = {0};
138	int ret;
139
140	if (!(priv->features & TA_RTC_FEATURE_CORRECTION))
141		return -EOPNOTSUPP;
142
143	inv_arg.func = TA_CMD_RTC_GET_OFFSET;
144	inv_arg.session = priv->session_id;
145	inv_arg.num_params = 4;
146
147	param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT;
148
149	ret = tee_client_invoke_func(priv->ctx, &inv_arg, param);
150	if (ret < 0 || inv_arg.ret != 0)
151		return ret ? ret : -EPROTO;
152
153	*offset = param[0].u.value.a;
154
155	return 0;
156}
157
158static int optee_rtc_setoffset(struct device *dev, long offset)
159{
160	struct optee_rtc *priv = dev_get_drvdata(dev);
161	struct tee_ioctl_invoke_arg inv_arg = {0};
162	struct tee_param param[4] = {0};
163	int ret;
164
165	if (!(priv->features & TA_RTC_FEATURE_CORRECTION))
166		return -EOPNOTSUPP;
167
168	inv_arg.func = TA_CMD_RTC_SET_OFFSET;
169	inv_arg.session = priv->session_id;
170	inv_arg.num_params = 4;
171
172	param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT;
173	param[0].u.value.a = offset;
174
175	ret = tee_client_invoke_func(priv->ctx, &inv_arg, param);
176	if (ret < 0 || inv_arg.ret != 0)
177		return ret ? ret : -EPROTO;
178
179	return 0;
180}
181
182static const struct rtc_class_ops optee_rtc_ops = {
183	.read_time	= optee_rtc_readtime,
184	.set_time	= optee_rtc_settime,
185	.set_offset	= optee_rtc_setoffset,
186	.read_offset	= optee_rtc_readoffset,
187};
188
189static int optee_rtc_read_info(struct device *dev, struct rtc_device *rtc,
190			       u64 *features)
191{
192	struct optee_rtc *priv = dev_get_drvdata(dev);
193	struct tee_ioctl_invoke_arg inv_arg = {0};
194	struct tee_param param[4] = {0};
195	struct optee_rtc_info *info;
196	struct optee_rtc_time *tm;
197	int ret;
198
199	inv_arg.func = TA_CMD_RTC_GET_INFO;
200	inv_arg.session = priv->session_id;
201	inv_arg.num_params = 4;
202
203	param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT;
204	param[0].u.memref.shm = priv->shm;
205	param[0].u.memref.size = sizeof(*info);
206
207	ret = tee_client_invoke_func(priv->ctx, &inv_arg, param);
208	if (ret < 0 || inv_arg.ret != 0)
209		return ret ? ret : -EPROTO;
210
211	info = tee_shm_get_va(priv->shm, 0);
212	if (IS_ERR(info))
213		return PTR_ERR(info);
214
215	if (param[0].u.memref.size != sizeof(*info))
216		return -EPROTO;
217
218	if (info->version != RTC_INFO_VERSION)
219		return -EPROTO;
220
221	*features = info->features;
222
223	tm = &info->range_min;
224	rtc->range_min = mktime64(tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_hour, tm->tm_min,
225				  tm->tm_sec);
226	tm = &info->range_max;
227	rtc->range_max = mktime64(tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_hour, tm->tm_min,
228				  tm->tm_sec);
229
230	return 0;
231}
232
233static int optee_ctx_match(struct tee_ioctl_version_data *ver, const void *data)
234{
235	if (ver->impl_id == TEE_IMPL_ID_OPTEE)
236		return 1;
237	else
238		return 0;
239}
240
241static int optee_rtc_probe(struct device *dev)
242{
243	struct tee_client_device *rtc_device = to_tee_client_device(dev);
244	struct tee_ioctl_open_session_arg sess_arg;
245	struct optee_rtc *priv;
246	struct rtc_device *rtc;
247	struct tee_shm *shm;
248	int ret, err;
249
250	memset(&sess_arg, 0, sizeof(sess_arg));
251
252	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
253	if (!priv)
254		return -ENOMEM;
255
256	rtc = devm_rtc_allocate_device(dev);
257	if (IS_ERR(rtc))
258		return PTR_ERR(rtc);
259
260	/* Open context with TEE driver */
261	priv->ctx = tee_client_open_context(NULL, optee_ctx_match, NULL, NULL);
262	if (IS_ERR(priv->ctx))
263		return -ENODEV;
264
265	/* Open session with rtc Trusted App */
266	export_uuid(sess_arg.uuid, &rtc_device->id.uuid);
267	sess_arg.clnt_login = TEE_IOCTL_LOGIN_REE_KERNEL;
268
269	ret = tee_client_open_session(priv->ctx, &sess_arg, NULL);
270	if (ret < 0 || sess_arg.ret != 0) {
271		dev_err(dev, "tee_client_open_session failed, err: %x\n", sess_arg.ret);
272		err = -EINVAL;
273		goto out_ctx;
274	}
275	priv->session_id = sess_arg.session;
276
277	shm = tee_shm_alloc_kernel_buf(priv->ctx, sizeof(struct optee_rtc_info));
278	if (IS_ERR(shm)) {
279		dev_err(priv->dev, "tee_shm_alloc_kernel_buf failed\n");
280		err = PTR_ERR(shm);
281		goto out_sess;
282	}
283
284	priv->shm = shm;
285	priv->dev = dev;
286	dev_set_drvdata(dev, priv);
287
288	rtc->ops = &optee_rtc_ops;
289
290	err = optee_rtc_read_info(dev, rtc, &priv->features);
291	if (err) {
292		dev_err(dev, "Failed to get RTC features from OP-TEE\n");
293		goto out_shm;
294	}
295
296	err = devm_rtc_register_device(rtc);
297	if (err)
298		goto out_shm;
299
300	/*
301	 * We must clear this bit after registering because rtc_register_device
302	 * will set it if it sees that .set_offset is provided.
303	 */
304	if (!(priv->features & TA_RTC_FEATURE_CORRECTION))
305		clear_bit(RTC_FEATURE_CORRECTION, rtc->features);
306
307	return 0;
308
309out_shm:
310	tee_shm_free(priv->shm);
311out_sess:
312	tee_client_close_session(priv->ctx, priv->session_id);
313out_ctx:
314	tee_client_close_context(priv->ctx);
315
316	return err;
317}
318
319static int optee_rtc_remove(struct device *dev)
320{
321	struct optee_rtc *priv = dev_get_drvdata(dev);
322
323	tee_client_close_session(priv->ctx, priv->session_id);
324	tee_client_close_context(priv->ctx);
325
326	return 0;
327}
328
329static const struct tee_client_device_id optee_rtc_id_table[] = {
330	{UUID_INIT(0xf389f8c8, 0x845f, 0x496c,
331		   0x8b, 0xbe, 0xd6, 0x4b, 0xd2, 0x4c, 0x92, 0xfd)},
332	{}
333};
334
335MODULE_DEVICE_TABLE(tee, optee_rtc_id_table);
336
337static struct tee_client_driver optee_rtc_driver = {
338	.id_table	= optee_rtc_id_table,
339	.driver		= {
340		.name		= "optee_rtc",
341		.bus		= &tee_bus_type,
342		.probe		= optee_rtc_probe,
343		.remove		= optee_rtc_remove,
344	},
345};
346
347static int __init optee_rtc_mod_init(void)
348{
349	return driver_register(&optee_rtc_driver.driver);
350}
351
352static void __exit optee_rtc_mod_exit(void)
353{
354	driver_unregister(&optee_rtc_driver.driver);
355}
356
357module_init(optee_rtc_mod_init);
358module_exit(optee_rtc_mod_exit);
359
360MODULE_LICENSE("GPL v2");
361MODULE_AUTHOR("Cl��ment L��ger <clement.leger@bootlin.com>");
362MODULE_DESCRIPTION("OP-TEE based RTC driver");
363