summaryrefslogtreecommitdiffstats
path: root/drivers/firmware/arm_scmi/optee.c
blob: e123de6e8c67a9719542666bd93116fe9cc41347 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2019-2021 Linaro Ltd.
 */

#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/tee_drv.h>
#include <linux/uuid.h>
#include <uapi/linux/tee.h>

#include "common.h"

#define SCMI_OPTEE_MAX_MSG_SIZE		128

enum scmi_optee_pta_cmd {
	/*
	 * PTA_SCMI_CMD_CAPABILITIES - Get channel capabilities
	 *
	 * [out]    value[0].a: Capability bit mask (enum pta_scmi_caps)
	 * [out]    value[0].b: Extended capabilities or 0
	 */
	PTA_SCMI_CMD_CAPABILITIES = 0,

	/*
	 * PTA_SCMI_CMD_PROCESS_SMT_CHANNEL - Process SCMI message in SMT buffer
	 *
	 * [in]     value[0].a: Channel handle
	 *
	 * Shared memory used for SCMI message/response exhange is expected
	 * already identified and bound to channel handle in both SCMI agent
	 * and SCMI server (OP-TEE) parts.
	 * The memory uses SMT header to carry SCMI meta-data (protocol ID and
	 * protocol message ID).
	 */
	PTA_SCMI_CMD_PROCESS_SMT_CHANNEL = 1,

	/*
	 * PTA_SCMI_CMD_PROCESS_SMT_CHANNEL_MESSAGE - Process SMT/SCMI message
	 *
	 * [in]     value[0].a: Channel handle
	 * [in/out] memref[1]: Message/response buffer (SMT and SCMI payload)
	 *
	 * Shared memory used for SCMI message/response is a SMT buffer
	 * referenced by param[1]. It shall be 128 bytes large to fit response
	 * payload whatever message playload size.
	 * The memory uses SMT header to carry SCMI meta-data (protocol ID and
	 * protocol message ID).
	 */
	PTA_SCMI_CMD_PROCESS_SMT_CHANNEL_MESSAGE = 2,

	/*
	 * PTA_SCMI_CMD_GET_CHANNEL - Get channel handle
	 *
	 * SCMI shm information are 0 if agent expects to use OP-TEE regular SHM
	 *
	 * [in]     value[0].a: Channel identifier
	 * [out]    value[0].a: Returned channel handle
	 * [in]     value[0].b: Requested capabilities mask (enum pta_scmi_caps)
	 */
	PTA_SCMI_CMD_GET_CHANNEL = 3,

	/*
	 * PTA_SCMI_CMD_PROCESS_MSG_CHANNEL - Process SCMI message in a MSG
	 * buffer pointed by memref parameters
	 *
	 * [in]     value[0].a: Channel handle
	 * [in]     memref[1]: Message buffer (MSG and SCMI payload)
	 * [out]    memref[2]: Response buffer (MSG and SCMI payload)
	 *
	 * Shared memories used for SCMI message/response are MSG buffers
	 * referenced by param[1] and param[2]. MSG transport protocol
	 * uses a 32bit header to carry SCMI meta-data (protocol ID and
	 * protocol message ID) followed by the effective SCMI message
	 * payload.
	 */
	PTA_SCMI_CMD_PROCESS_MSG_CHANNEL = 4,
};

/*
 * OP-TEE SCMI service capabilities bit flags (32bit)
 *
 * PTA_SCMI_CAPS_SMT_HEADER
 * When set, OP-TEE supports command using SMT header protocol (SCMI shmem) in
 * shared memory buffers to carry SCMI protocol synchronisation information.
 *
 * PTA_SCMI_CAPS_MSG_HEADER
 * When set, OP-TEE supports command using MSG header protocol in an OP-TEE
 * shared memory to carry SCMI protocol synchronisation information and SCMI
 * message payload.
 */
#define PTA_SCMI_CAPS_NONE		0
#define PTA_SCMI_CAPS_SMT_HEADER	BIT(0)
#define PTA_SCMI_CAPS_MSG_HEADER	BIT(1)
#define PTA_SCMI_CAPS_MASK		(PTA_SCMI_CAPS_SMT_HEADER | \
					 PTA_SCMI_CAPS_MSG_HEADER)

/**
 * struct scmi_optee_channel - Description of an OP-TEE SCMI channel
 *
 * @channel_id: OP-TEE channel ID used for this transport
 * @tee_session: TEE session identifier
 * @caps: OP-TEE SCMI channel capabilities
 * @rx_len: Response size
 * @mu: Mutex protection on channel access
 * @cinfo: SCMI channel information
 * @shmem: Virtual base address of the shared memory
 * @req: Shared memory protocol handle for SCMI request and synchronous response
 * @tee_shm: TEE shared memory handle @req or NULL if using IOMEM shmem
 * @link: Reference in agent's channel list
 */
struct scmi_optee_channel {
	u32 channel_id;
	u32 tee_session;
	u32 caps;
	u32 rx_len;
	struct mutex mu;
	struct scmi_chan_info *cinfo;
	union {
		struct scmi_shared_mem __iomem *shmem;
		struct scmi_msg_payld *msg;
	} req;
	struct tee_shm *tee_shm;
	struct list_head link;
};

/**
 * struct scmi_optee_agent - OP-TEE transport private data
 *
 * @dev: Device used for communication with TEE
 * @tee_ctx: TEE context used for communication
 * @caps: Supported channel capabilities
 * @mu: Mutex for protection of @channel_list
 * @channel_list: List of all created channels for the agent
 */
struct scmi_optee_agent {
	struct device *dev;
	struct tee_context *tee_ctx;
	u32 caps;
	struct mutex mu;
	struct list_head channel_list;
};

/* There can be only 1 SCMI service in OP-TEE we connect to */
static struct scmi_optee_agent *scmi_optee_private;

/* Forward reference to scmi_optee transport initialization */
static int scmi_optee_init(void);

/* Open a session toward SCMI OP-TEE service with REE_KERNEL identity */
static int open_session(struct scmi_optee_agent *agent, u32 *tee_session)
{
	struct device *dev = agent->dev;
	struct tee_client_device *scmi_pta = to_tee_client_device(dev);
	struct tee_ioctl_open_session_arg arg = { };
	int ret;

	memcpy(arg.uuid, scmi_pta->id.uuid.b, TEE_IOCTL_UUID_LEN);
	arg.clnt_login = TEE_IOCTL_LOGIN_REE_KERNEL;

	ret = tee_client_open_session(agent->tee_ctx, &arg, NULL);
	if (ret < 0 || arg.ret) {
		dev_err(dev, "Can't open tee session: %d / %#x\n", ret, arg.ret);
		return -EOPNOTSUPP;
	}

	*tee_session = arg.session;

	return 0;
}

static void close_session(struct scmi_optee_agent *agent, u32 tee_session)
{
	tee_client_close_session(agent->tee_ctx, tee_session);
}

static int get_capabilities(struct scmi_optee_agent *agent)
{
	struct tee_ioctl_invoke_arg arg = { };
	struct tee_param param[1] = { };
	u32 caps;
	u32 tee_session;
	int ret;

	ret = open_session(agent, &tee_session);
	if (ret)
		return ret;

	arg.func = PTA_SCMI_CMD_CAPABILITIES;
	arg.session = tee_session;
	arg.num_params = 1;

	param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT;

	ret = tee_client_invoke_func(agent->tee_ctx, &arg, param);

	close_session(agent, tee_session);

	if (ret < 0 || arg.ret) {
		dev_err(agent->dev, "Can't get capabilities: %d / %#x\n", ret, arg.ret);
		return -EOPNOTSUPP;
	}

	caps = param[0].u.value.a;

	if (!(caps & (PTA_SCMI_CAPS_SMT_HEADER | PTA_SCMI_CAPS_MSG_HEADER))) {
		dev_err(agent->dev, "OP-TEE SCMI PTA doesn't support SMT and MSG\n");
		return -EOPNOTSUPP;
	}

	agent->caps = caps;

	return 0;
}

static int get_channel(struct scmi_optee_channel *channel)
{
	struct device *dev = scmi_optee_private->dev;
	struct tee_ioctl_invoke_arg arg = { };
	struct tee_param param[1] = { };
	unsigned int caps = 0;
	int ret;

	if (channel->tee_shm)
		caps = PTA_SCMI_CAPS_MSG_HEADER;
	else
		caps = PTA_SCMI_CAPS_SMT_HEADER;

	arg.func = PTA_SCMI_CMD_GET_CHANNEL;
	arg.session = channel->tee_session;
	arg.num_params = 1;

	param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INOUT;
	param[0].u.value.a = channel->channel_id;
	param[0].u.value.b = caps;

	ret = tee_client_invoke_func(scmi_optee_private->tee_ctx, &arg, param);

	if (ret || arg.ret) {
		dev_err(dev, "Can't get channel with caps %#x: %d / %#x\n", caps, ret, arg.ret);
		return -EOPNOTSUPP;
	}

	/* From now on use channel identifer provided by OP-TEE SCMI service */
	channel->channel_id = param[0].u.value.a;
	channel->caps = caps;

	return 0;
}

static int invoke_process_smt_channel(struct scmi_optee_channel *channel)
{
	struct tee_ioctl_invoke_arg arg = {
		.func = PTA_SCMI_CMD_PROCESS_SMT_CHANNEL,
		.session = channel->tee_session,
		.num_params = 1,
	};
	struct tee_param param[1] = { };
	int ret;

	param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT;
	param[0].u.value.a = channel->channel_id;

	ret = tee_client_invoke_func(scmi_optee_private->tee_ctx, &arg, param);
	if (ret < 0 || arg.ret) {
		dev_err(scmi_optee_private->dev, "Can't invoke channel %u: %d / %#x\n",
			channel->channel_id, ret, arg.ret);
		return -EIO;
	}

	return 0;
}

static int invoke_process_msg_channel(struct scmi_optee_channel *channel, size_t msg_size)
{
	struct tee_ioctl_invoke_arg arg = {
		.func = PTA_SCMI_CMD_PROCESS_MSG_CHANNEL,
		.session = channel->tee_session,
		.num_params = 3,
	};
	struct tee_param param[3] = { };
	int ret;

	param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT;
	param[0].u.value.a = channel->channel_id;

	param[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT;
	param[1].u.memref.shm = channel->tee_shm;
	param[1].u.memref.size = msg_size;

	param[2].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT;
	param[2].u.memref.shm = channel->tee_shm;
	param[2].u.memref.size = SCMI_OPTEE_MAX_MSG_SIZE;

	ret = tee_client_invoke_func(scmi_optee_private->tee_ctx, &arg, param);
	if (ret < 0 || arg.ret) {
		dev_err(scmi_optee_private->dev, "Can't invoke channel %u: %d / %#x\n",
			channel->channel_id, ret, arg.ret);
		return -EIO;
	}

	/* Save response size */
	channel->rx_len = param[2].u.memref.size;

	return 0;
}

static int scmi_optee_link_supplier(struct device *dev)
{
	if (!scmi_optee_private) {
		if (scmi_optee_init())
			dev_dbg(dev, "Optee bus not yet ready\n");

		/* Wait for optee bus */
		return -EPROBE_DEFER;
	}

	if (!device_link_add(dev, scmi_optee_private->dev, DL_FLAG_AUTOREMOVE_CONSUMER)) {
		dev_err(dev, "Adding link to supplier optee device failed\n");
		return -ECANCELED;
	}

	return 0;
}

static bool scmi_optee_chan_available(struct device_node *of_node, int idx)
{
	u32 channel_id;

	return !of_property_read_u32_index(of_node, "linaro,optee-channel-id",
					   idx, &channel_id);
}

static void scmi_optee_clear_channel(struct scmi_chan_info *cinfo)
{
	struct scmi_optee_channel *channel = cinfo->transport_info;

	if (!channel->tee_shm)
		shmem_clear_channel(channel->req.shmem);
}

static int setup_dynamic_shmem(struct device *dev, struct scmi_optee_channel *channel)
{
	const size_t msg_size = SCMI_OPTEE_MAX_MSG_SIZE;
	void *shbuf;

	channel->tee_shm = tee_shm_alloc_kernel_buf(scmi_optee_private->tee_ctx, msg_size);
	if (IS_ERR(channel->tee_shm)) {
		dev_err(channel->cinfo->dev, "shmem allocation failed\n");
		return -ENOMEM;
	}

	shbuf = tee_shm_get_va(channel->tee_shm, 0);
	memset(shbuf, 0, msg_size);
	channel->req.msg = shbuf;
	channel->rx_len = msg_size;

	return 0;
}

static int setup_static_shmem(struct device *dev, struct scmi_chan_info *cinfo,
			      struct scmi_optee_channel *channel)
{
	struct device_node *np;
	resource_size_t size;
	struct resource res;
	int ret;

	np = of_parse_phandle(cinfo->dev->of_node, "shmem", 0);
	if (!of_device_is_compatible(np, "arm,scmi-shmem")) {
		ret = -ENXIO;
		goto out;
	}

	ret = of_address_to_resource(np, 0, &res);
	if (ret) {
		dev_err(dev, "Failed to get SCMI Tx shared memory\n");
		goto out;
	}

	size = resource_size(&res);

	channel->req.shmem = devm_ioremap(dev, res.start, size);
	if (!channel->req.shmem) {
		dev_err(dev, "Failed to ioremap SCMI Tx shared memory\n");
		ret = -EADDRNOTAVAIL;
		goto out;
	}

	ret = 0;

out:
	of_node_put(np);

	return ret;
}

static int setup_shmem(struct device *dev, struct scmi_chan_info *cinfo,
		       struct scmi_optee_channel *channel)
{
	if (of_property_present(cinfo->dev->of_node, "shmem"))
		return setup_static_shmem(dev, cinfo, channel);
	else
		return setup_dynamic_shmem(dev, channel);
}

static int scmi_optee_chan_setup(struct scmi_chan_info *cinfo, struct device *dev, bool tx)
{
	struct scmi_optee_channel *channel;
	uint32_t channel_id;
	int ret;

	if (!tx)
		return -ENODEV;

	channel = devm_kzalloc(dev, sizeof(*channel), GFP_KERNEL);
	if (!channel)
		return -ENOMEM;

	ret = of_property_read_u32_index(cinfo->dev->of_node, "linaro,optee-channel-id",
					 0, &channel_id);
	if (ret)
		return ret;

	cinfo->transport_info = channel;
	channel->cinfo = cinfo;
	channel->channel_id = channel_id;
	mutex_init(&channel->mu);

	ret = setup_shmem(dev, cinfo, channel);
	if (ret)
		return ret;

	ret = open_session(scmi_optee_private, &channel->tee_session);
	if (ret)
		goto err_free_shm;

	ret = get_channel(channel);
	if (ret)
		goto err_close_sess;

	/* Enable polling */
	cinfo->no_completion_irq = true;

	mutex_lock(&scmi_optee_private->mu);
	list_add(&channel->link, &scmi_optee_private->channel_list);
	mutex_unlock(&scmi_optee_private->mu);

	return 0;

err_close_sess:
	close_session(scmi_optee_private, channel->tee_session);
err_free_shm:
	if (channel->tee_shm)
		tee_shm_free(channel->tee_shm);

	return ret;
}

static int scmi_optee_chan_free(int id, void *p, void *data)
{
	struct scmi_chan_info *cinfo = p;
	struct scmi_optee_channel *channel = cinfo->transport_info;

	mutex_lock(&scmi_optee_private->mu);
	list_del(&channel->link);
	mutex_unlock(&scmi_optee_private->mu);

	close_session(scmi_optee_private, channel->tee_session);

	if (channel->tee_shm) {
		tee_shm_free(channel->tee_shm);
		channel->tee_shm = NULL;
	}

	cinfo->transport_info = NULL;
	channel->cinfo = NULL;

	return 0;
}

static int scmi_optee_send_message(struct scmi_chan_info *cinfo,
				   struct scmi_xfer *xfer)
{
	struct scmi_optee_channel *channel = cinfo->transport_info;
	int ret;

	mutex_lock(&channel->mu);

	if (channel->tee_shm) {
		msg_tx_prepare(channel->req.msg, xfer);
		ret = invoke_process_msg_channel(channel, msg_command_size(xfer));
	} else {
		shmem_tx_prepare(channel->req.shmem, xfer, cinfo);
		ret = invoke_process_smt_channel(channel);
	}

	if (ret)
		mutex_unlock(&channel->mu);

	return ret;
}

static void scmi_optee_fetch_response(struct scmi_chan_info *cinfo,
				      struct scmi_xfer *xfer)
{
	struct scmi_optee_channel *channel = cinfo->transport_info;

	if (channel->tee_shm)
		msg_fetch_response(channel->req.msg, channel->rx_len, xfer);
	else
		shmem_fetch_response(channel->req.shmem, xfer);
}

static void scmi_optee_mark_txdone(struct scmi_chan_info *cinfo, int ret,
				   struct scmi_xfer *__unused)
{
	struct scmi_optee_channel *channel = cinfo->transport_info;

	mutex_unlock(&channel->mu);
}

static struct scmi_transport_ops scmi_optee_ops = {
	.link_supplier = scmi_optee_link_supplier,
	.chan_available = scmi_optee_chan_available,
	.chan_setup = scmi_optee_chan_setup,
	.chan_free = scmi_optee_chan_free,
	.send_message = scmi_optee_send_message,
	.mark_txdone = scmi_optee_mark_txdone,
	.fetch_response = scmi_optee_fetch_response,
	.clear_channel = scmi_optee_clear_channel,
};

static int scmi_optee_ctx_match(struct tee_ioctl_version_data *ver, const void *data)
{
	return ver->impl_id == TEE_IMPL_ID_OPTEE;
}

static int scmi_optee_service_probe(struct device *dev)
{
	struct scmi_optee_agent *agent;
	struct tee_context *tee_ctx;
	int ret;

	/* Only one SCMI OP-TEE device allowed */
	if (scmi_optee_private) {
		dev_err(dev, "An SCMI OP-TEE device was already initialized: only one allowed\n");
		return -EBUSY;
	}

	tee_ctx = tee_client_open_context(NULL, scmi_optee_ctx_match, NULL, NULL);
	if (IS_ERR(tee_ctx))
		return -ENODEV;

	agent = devm_kzalloc(dev, sizeof(*agent), GFP_KERNEL);
	if (!agent) {
		ret = -ENOMEM;
		goto err;
	}

	agent->dev = dev;
	agent->tee_ctx = tee_ctx;
	INIT_LIST_HEAD(&agent->channel_list);
	mutex_init(&agent->mu);

	ret = get_capabilities(agent);
	if (ret)
		goto err;

	/* Ensure agent resources are all visible before scmi_optee_private is */
	smp_mb();
	scmi_optee_private = agent;

	return 0;

err:
	tee_client_close_context(tee_ctx);

	return ret;
}

static int scmi_optee_service_remove(struct device *dev)
{
	struct scmi_optee_agent *agent = scmi_optee_private;

	if (!scmi_optee_private)
		return -EINVAL;

	if (!list_empty(&scmi_optee_private->channel_list))
		return -EBUSY;

	/* Ensure cleared reference is visible before resources are released */
	smp_store_mb(scmi_optee_private, NULL);

	tee_client_close_context(agent->tee_ctx);

	return 0;
}

static const struct tee_client_device_id scmi_optee_service_id[] = {
	{
		UUID_INIT(0xa8cfe406, 0xd4f5, 0x4a2e,
			  0x9f, 0x8d, 0xa2, 0x5d, 0xc7, 0x54, 0xc0, 0x99)
	},
	{ }
};

MODULE_DEVICE_TABLE(tee, scmi_optee_service_id);

static struct tee_client_driver scmi_optee_driver = {
	.id_table	= scmi_optee_service_id,
	.driver		= {
		.name = "scmi-optee",
		.bus = &tee_bus_type,
		.probe = scmi_optee_service_probe,
		.remove = scmi_optee_service_remove,
	},
};

static int scmi_optee_init(void)
{
	return driver_register(&scmi_optee_driver.driver);
}

static void scmi_optee_exit(void)
{
	if (scmi_optee_private)
		driver_unregister(&scmi_optee_driver.driver);
}

const struct scmi_desc scmi_optee_desc = {
	.transport_exit = scmi_optee_exit,
	.ops = &scmi_optee_ops,
	.max_rx_timeout_ms = 30,
	.max_msg = 20,
	.max_msg_size = SCMI_OPTEE_MAX_MSG_SIZE,
	.sync_cmds_completed_on_ret = true,
};