summaryrefslogtreecommitdiffstats
path: root/drivers/firmware/arm_scpi.c
blob: 7e3e595c9f3011602cb08293fa38a29e94021e8a (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
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
/*
 * System Control and Power Interface (SCPI) Message Protocol driver
 *
 * SCPI Message Protocol is used between the System Control Processor(SCP)
 * and the Application Processors(AP). The Message Handling Unit(MHU)
 * provides a mechanism for inter-processor communication between SCP's
 * Cortex M3 and AP.
 *
 * SCP offers control and management of the core/cluster power states,
 * various power domain DVFS including the core/cluster, certain system
 * clocks configuration, thermal sensors and many others.
 *
 * Copyright (C) 2015 ARM Ltd.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program. If not, see <http://www.gnu.org/licenses/>.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/bitmap.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/mailbox_client.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/of_platform.h>
#include <linux/printk.h>
#include <linux/scpi_protocol.h>
#include <linux/slab.h>
#include <linux/sort.h>
#include <linux/spinlock.h>

#define CMD_ID_SHIFT		0
#define CMD_ID_MASK		0x7f
#define CMD_TOKEN_ID_SHIFT	8
#define CMD_TOKEN_ID_MASK	0xff
#define CMD_DATA_SIZE_SHIFT	16
#define CMD_DATA_SIZE_MASK	0x1ff
#define PACK_SCPI_CMD(cmd_id, tx_sz)			\
	((((cmd_id) & CMD_ID_MASK) << CMD_ID_SHIFT) |	\
	(((tx_sz) & CMD_DATA_SIZE_MASK) << CMD_DATA_SIZE_SHIFT))
#define ADD_SCPI_TOKEN(cmd, token)			\
	((cmd) |= (((token) & CMD_TOKEN_ID_MASK) << CMD_TOKEN_ID_SHIFT))

#define CMD_SIZE(cmd)	(((cmd) >> CMD_DATA_SIZE_SHIFT) & CMD_DATA_SIZE_MASK)
#define CMD_UNIQ_MASK	(CMD_TOKEN_ID_MASK << CMD_TOKEN_ID_SHIFT | CMD_ID_MASK)
#define CMD_XTRACT_UNIQ(cmd)	((cmd) & CMD_UNIQ_MASK)

#define SCPI_SLOT		0

#define MAX_DVFS_DOMAINS	8
#define MAX_DVFS_OPPS		8
#define DVFS_LATENCY(hdr)	(le32_to_cpu(hdr) >> 16)
#define DVFS_OPP_COUNT(hdr)	((le32_to_cpu(hdr) >> 8) & 0xff)

#define PROTOCOL_REV_MINOR_BITS	16
#define PROTOCOL_REV_MINOR_MASK	((1U << PROTOCOL_REV_MINOR_BITS) - 1)
#define PROTOCOL_REV_MAJOR(x)	((x) >> PROTOCOL_REV_MINOR_BITS)
#define PROTOCOL_REV_MINOR(x)	((x) & PROTOCOL_REV_MINOR_MASK)

#define FW_REV_MAJOR_BITS	24
#define FW_REV_MINOR_BITS	16
#define FW_REV_PATCH_MASK	((1U << FW_REV_MINOR_BITS) - 1)
#define FW_REV_MINOR_MASK	((1U << FW_REV_MAJOR_BITS) - 1)
#define FW_REV_MAJOR(x)		((x) >> FW_REV_MAJOR_BITS)
#define FW_REV_MINOR(x)		(((x) & FW_REV_MINOR_MASK) >> FW_REV_MINOR_BITS)
#define FW_REV_PATCH(x)		((x) & FW_REV_PATCH_MASK)

#define MAX_RX_TIMEOUT		(msecs_to_jiffies(30))

enum scpi_error_codes {
	SCPI_SUCCESS = 0, /* Success */
	SCPI_ERR_PARAM = 1, /* Invalid parameter(s) */
	SCPI_ERR_ALIGN = 2, /* Invalid alignment */
	SCPI_ERR_SIZE = 3, /* Invalid size */
	SCPI_ERR_HANDLER = 4, /* Invalid handler/callback */
	SCPI_ERR_ACCESS = 5, /* Invalid access/permission denied */
	SCPI_ERR_RANGE = 6, /* Value out of range */
	SCPI_ERR_TIMEOUT = 7, /* Timeout has occurred */
	SCPI_ERR_NOMEM = 8, /* Invalid memory area or pointer */
	SCPI_ERR_PWRSTATE = 9, /* Invalid power state */
	SCPI_ERR_SUPPORT = 10, /* Not supported or disabled */
	SCPI_ERR_DEVICE = 11, /* Device error */
	SCPI_ERR_BUSY = 12, /* Device busy */
	SCPI_ERR_MAX
};

enum scpi_std_cmd {
	SCPI_CMD_INVALID		= 0x00,
	SCPI_CMD_SCPI_READY		= 0x01,
	SCPI_CMD_SCPI_CAPABILITIES	= 0x02,
	SCPI_CMD_SET_CSS_PWR_STATE	= 0x03,
	SCPI_CMD_GET_CSS_PWR_STATE	= 0x04,
	SCPI_CMD_SET_SYS_PWR_STATE	= 0x05,
	SCPI_CMD_SET_CPU_TIMER		= 0x06,
	SCPI_CMD_CANCEL_CPU_TIMER	= 0x07,
	SCPI_CMD_DVFS_CAPABILITIES	= 0x08,
	SCPI_CMD_GET_DVFS_INFO		= 0x09,
	SCPI_CMD_SET_DVFS		= 0x0a,
	SCPI_CMD_GET_DVFS		= 0x0b,
	SCPI_CMD_GET_DVFS_STAT		= 0x0c,
	SCPI_CMD_CLOCK_CAPABILITIES	= 0x0d,
	SCPI_CMD_GET_CLOCK_INFO		= 0x0e,
	SCPI_CMD_SET_CLOCK_VALUE	= 0x0f,
	SCPI_CMD_GET_CLOCK_VALUE	= 0x10,
	SCPI_CMD_PSU_CAPABILITIES	= 0x11,
	SCPI_CMD_GET_PSU_INFO		= 0x12,
	SCPI_CMD_SET_PSU		= 0x13,
	SCPI_CMD_GET_PSU		= 0x14,
	SCPI_CMD_SENSOR_CAPABILITIES	= 0x15,
	SCPI_CMD_SENSOR_INFO		= 0x16,
	SCPI_CMD_SENSOR_VALUE		= 0x17,
	SCPI_CMD_SENSOR_CFG_PERIODIC	= 0x18,
	SCPI_CMD_SENSOR_CFG_BOUNDS	= 0x19,
	SCPI_CMD_SENSOR_ASYNC_VALUE	= 0x1a,
	SCPI_CMD_SET_DEVICE_PWR_STATE	= 0x1b,
	SCPI_CMD_GET_DEVICE_PWR_STATE	= 0x1c,
	SCPI_CMD_COUNT
};

struct scpi_xfer {
	u32 slot; /* has to be first element */
	u32 cmd;
	u32 status;
	const void *tx_buf;
	void *rx_buf;
	unsigned int tx_len;
	unsigned int rx_len;
	struct list_head node;
	struct completion done;
};

struct scpi_chan {
	struct mbox_client cl;
	struct mbox_chan *chan;
	void __iomem *tx_payload;
	void __iomem *rx_payload;
	struct list_head rx_pending;
	struct list_head xfers_list;
	struct scpi_xfer *xfers;
	spinlock_t rx_lock; /* locking for the rx pending list */
	struct mutex xfers_lock;
	u8 token;
};

struct scpi_drvinfo {
	u32 protocol_version;
	u32 firmware_version;
	int num_chans;
	atomic_t next_chan;
	struct scpi_ops *scpi_ops;
	struct scpi_chan *channels;
	struct scpi_dvfs_info *dvfs[MAX_DVFS_DOMAINS];
};

/*
 * The SCP firmware only executes in little-endian mode, so any buffers
 * shared through SCPI should have their contents converted to little-endian
 */
struct scpi_shared_mem {
	__le32 command;
	__le32 status;
	u8 payload[0];
} __packed;

struct scp_capabilities {
	__le32 protocol_version;
	__le32 event_version;
	__le32 platform_version;
	__le32 commands[4];
} __packed;

struct clk_get_info {
	__le16 id;
	__le16 flags;
	__le32 min_rate;
	__le32 max_rate;
	u8 name[20];
} __packed;

struct clk_get_value {
	__le32 rate;
} __packed;

struct clk_set_value {
	__le16 id;
	__le16 reserved;
	__le32 rate;
} __packed;

struct dvfs_info {
	__le32 header;
	struct {
		__le32 freq;
		__le32 m_volt;
	} opps[MAX_DVFS_OPPS];
} __packed;

struct dvfs_get {
	u8 index;
} __packed;

struct dvfs_set {
	u8 domain;
	u8 index;
} __packed;

struct sensor_capabilities {
	__le16 sensors;
} __packed;

struct _scpi_sensor_info {
	__le16 sensor_id;
	u8 class;
	u8 trigger_type;
	char name[20];
};

struct sensor_value {
	__le32 lo_val;
	__le32 hi_val;
} __packed;

static struct scpi_drvinfo *scpi_info;

static int scpi_linux_errmap[SCPI_ERR_MAX] = {
	/* better than switch case as long as return value is continuous */
	0, /* SCPI_SUCCESS */
	-EINVAL, /* SCPI_ERR_PARAM */
	-ENOEXEC, /* SCPI_ERR_ALIGN */
	-EMSGSIZE, /* SCPI_ERR_SIZE */
	-EINVAL, /* SCPI_ERR_HANDLER */
	-EACCES, /* SCPI_ERR_ACCESS */
	-ERANGE, /* SCPI_ERR_RANGE */
	-ETIMEDOUT, /* SCPI_ERR_TIMEOUT */
	-ENOMEM, /* SCPI_ERR_NOMEM */
	-EINVAL, /* SCPI_ERR_PWRSTATE */
	-EOPNOTSUPP, /* SCPI_ERR_SUPPORT */
	-EIO, /* SCPI_ERR_DEVICE */
	-EBUSY, /* SCPI_ERR_BUSY */
};

static inline int scpi_to_linux_errno(int errno)
{
	if (errno >= SCPI_SUCCESS && errno < SCPI_ERR_MAX)
		return scpi_linux_errmap[errno];
	return -EIO;
}

static void scpi_process_cmd(struct scpi_chan *ch, u32 cmd)
{
	unsigned long flags;
	struct scpi_xfer *t, *match = NULL;

	spin_lock_irqsave(&ch->rx_lock, flags);
	if (list_empty(&ch->rx_pending)) {
		spin_unlock_irqrestore(&ch->rx_lock, flags);
		return;
	}

	list_for_each_entry(t, &ch->rx_pending, node)
		if (CMD_XTRACT_UNIQ(t->cmd) == CMD_XTRACT_UNIQ(cmd)) {
			list_del(&t->node);
			match = t;
			break;
		}
	/* check if wait_for_completion is in progress or timed-out */
	if (match && !completion_done(&match->done)) {
		struct scpi_shared_mem *mem = ch->rx_payload;
		unsigned int len = min(match->rx_len, CMD_SIZE(cmd));

		match->status = le32_to_cpu(mem->status);
		memcpy_fromio(match->rx_buf, mem->payload, len);
		if (match->rx_len > len)
			memset(match->rx_buf + len, 0, match->rx_len - len);
		complete(&match->done);
	}
	spin_unlock_irqrestore(&ch->rx_lock, flags);
}

static void scpi_handle_remote_msg(struct mbox_client *c, void *msg)
{
	struct scpi_chan *ch = container_of(c, struct scpi_chan, cl);
	struct scpi_shared_mem *mem = ch->rx_payload;
	u32 cmd = le32_to_cpu(mem->command);

	scpi_process_cmd(ch, cmd);
}

static void scpi_tx_prepare(struct mbox_client *c, void *msg)
{
	unsigned long flags;
	struct scpi_xfer *t = msg;
	struct scpi_chan *ch = container_of(c, struct scpi_chan, cl);
	struct scpi_shared_mem *mem = (struct scpi_shared_mem *)ch->tx_payload;

	if (t->tx_buf)
		memcpy_toio(mem->payload, t->tx_buf, t->tx_len);
	if (t->rx_buf) {
		if (!(++ch->token))
			++ch->token;
		ADD_SCPI_TOKEN(t->cmd, ch->token);
		spin_lock_irqsave(&ch->rx_lock, flags);
		list_add_tail(&t->node, &ch->rx_pending);
		spin_unlock_irqrestore(&ch->rx_lock, flags);
	}
	mem->command = cpu_to_le32(t->cmd);
}

static struct scpi_xfer *get_scpi_xfer(struct scpi_chan *ch)
{
	struct scpi_xfer *t;

	mutex_lock(&ch->xfers_lock);
	if (list_empty(&ch->xfers_list)) {
		mutex_unlock(&ch->xfers_lock);
		return NULL;
	}
	t = list_first_entry(&ch->xfers_list, struct scpi_xfer, node);
	list_del(&t->node);
	mutex_unlock(&ch->xfers_lock);
	return t;
}

static void put_scpi_xfer(struct scpi_xfer *t, struct scpi_chan *ch)
{
	mutex_lock(&ch->xfers_lock);
	list_add_tail(&t->node, &ch->xfers_list);
	mutex_unlock(&ch->xfers_lock);
}

static int scpi_send_message(u8 cmd, void *tx_buf, unsigned int tx_len,
			     void *rx_buf, unsigned int rx_len)
{
	int ret;
	u8 chan;
	struct scpi_xfer *msg;
	struct scpi_chan *scpi_chan;

	chan = atomic_inc_return(&scpi_info->next_chan) % scpi_info->num_chans;
	scpi_chan = scpi_info->channels + chan;

	msg = get_scpi_xfer(scpi_chan);
	if (!msg)
		return -ENOMEM;

	msg->slot = BIT(SCPI_SLOT);
	msg->cmd = PACK_SCPI_CMD(cmd, tx_len);
	msg->tx_buf = tx_buf;
	msg->tx_len = tx_len;
	msg->rx_buf = rx_buf;
	msg->rx_len = rx_len;
	init_completion(&msg->done);

	ret = mbox_send_message(scpi_chan->chan, msg);
	if (ret < 0 || !rx_buf)
		goto out;

	if (!wait_for_completion_timeout(&msg->done, MAX_RX_TIMEOUT))
		ret = -ETIMEDOUT;
	else
		/* first status word */
		ret = msg->status;
out:
	if (ret < 0 && rx_buf) /* remove entry from the list if timed-out */
		scpi_process_cmd(scpi_chan, msg->cmd);

	put_scpi_xfer(msg, scpi_chan);
	/* SCPI error codes > 0, translate them to Linux scale*/
	return ret > 0 ? scpi_to_linux_errno(ret) : ret;
}

static u32 scpi_get_version(void)
{
	return scpi_info->protocol_version;
}

static int
scpi_clk_get_range(u16 clk_id, unsigned long *min, unsigned long *max)
{
	int ret;
	struct clk_get_info clk;
	__le16 le_clk_id = cpu_to_le16(clk_id);

	ret = scpi_send_message(SCPI_CMD_GET_CLOCK_INFO, &le_clk_id,
				sizeof(le_clk_id), &clk, sizeof(clk));
	if (!ret) {
		*min = le32_to_cpu(clk.min_rate);
		*max = le32_to_cpu(clk.max_rate);
	}
	return ret;
}

static unsigned long scpi_clk_get_val(u16 clk_id)
{
	int ret;
	struct clk_get_value clk;
	__le16 le_clk_id = cpu_to_le16(clk_id);

	ret = scpi_send_message(SCPI_CMD_GET_CLOCK_VALUE, &le_clk_id,
				sizeof(le_clk_id), &clk, sizeof(clk));
	return ret ? ret : le32_to_cpu(clk.rate);
}

static int scpi_clk_set_val(u16 clk_id, unsigned long rate)
{
	int stat;
	struct clk_set_value clk = {
		.id = cpu_to_le16(clk_id),
		.rate = cpu_to_le32(rate)
	};

	return scpi_send_message(SCPI_CMD_SET_CLOCK_VALUE, &clk, sizeof(clk),
				 &stat, sizeof(stat));
}

static int scpi_dvfs_get_idx(u8 domain)
{
	int ret;
	struct dvfs_get dvfs;

	ret = scpi_send_message(SCPI_CMD_GET_DVFS, &domain, sizeof(domain),
				&dvfs, sizeof(dvfs));
	return ret ? ret : dvfs.index;
}

static int scpi_dvfs_set_idx(u8 domain, u8 index)
{
	int stat;
	struct dvfs_set dvfs = {domain, index};

	return scpi_send_message(SCPI_CMD_SET_DVFS, &dvfs, sizeof(dvfs),
				 &stat, sizeof(stat));
}

static int opp_cmp_func(const void *opp1, const void *opp2)
{
	const struct scpi_opp *t1 = opp1, *t2 = opp2;

	return t1->freq - t2->freq;
}

static struct scpi_dvfs_info *scpi_dvfs_get_info(u8 domain)
{
	struct scpi_dvfs_info *info;
	struct scpi_opp *opp;
	struct dvfs_info buf;
	int ret, i;

	if (domain >= MAX_DVFS_DOMAINS)
		return ERR_PTR(-EINVAL);

	if (scpi_info->dvfs[domain])	/* data already populated */
		return scpi_info->dvfs[domain];

	ret = scpi_send_message(SCPI_CMD_GET_DVFS_INFO, &domain, sizeof(domain),
				&buf, sizeof(buf));

	if (ret)
		return ERR_PTR(ret);

	info = kmalloc(sizeof(*info), GFP_KERNEL);
	if (!info)
		return ERR_PTR(-ENOMEM);

	info->count = DVFS_OPP_COUNT(buf.header);
	info->latency = DVFS_LATENCY(buf.header) * 1000; /* uS to nS */

	info->opps = kcalloc(info->count, sizeof(*opp), GFP_KERNEL);
	if (!info->opps) {
		kfree(info);
		return ERR_PTR(-ENOMEM);
	}

	for (i = 0, opp = info->opps; i < info->count; i++, opp++) {
		opp->freq = le32_to_cpu(buf.opps[i].freq);
		opp->m_volt = le32_to_cpu(buf.opps[i].m_volt);
	}

	sort(info->opps, info->count, sizeof(*opp), opp_cmp_func, NULL);

	scpi_info->dvfs[domain] = info;
	return info;
}

static int scpi_sensor_get_capability(u16 *sensors)
{
	struct sensor_capabilities cap_buf;
	int ret;

	ret = scpi_send_message(SCPI_CMD_SENSOR_CAPABILITIES, NULL, 0, &cap_buf,
				sizeof(cap_buf));
	if (!ret)
		*sensors = le16_to_cpu(cap_buf.sensors);

	return ret;
}

static int scpi_sensor_get_info(u16 sensor_id, struct scpi_sensor_info *info)
{
	__le16 id = cpu_to_le16(sensor_id);
	struct _scpi_sensor_info _info;
	int ret;

	ret = scpi_send_message(SCPI_CMD_SENSOR_INFO, &id, sizeof(id),
				&_info, sizeof(_info));
	if (!ret) {
		memcpy(info, &_info, sizeof(*info));
		info->sensor_id = le16_to_cpu(_info.sensor_id);
	}

	return ret;
}

int scpi_sensor_get_value(u16 sensor, u64 *val)
{
	__le16 id = cpu_to_le16(sensor);
	struct sensor_value buf;
	int ret;

	ret = scpi_send_message(SCPI_CMD_SENSOR_VALUE, &id, sizeof(id),
				&buf, sizeof(buf));
	if (!ret)
		*val = (u64)le32_to_cpu(buf.hi_val) << 32 |
			le32_to_cpu(buf.lo_val);

	return ret;
}

static struct scpi_ops scpi_ops = {
	.get_version = scpi_get_version,
	.clk_get_range = scpi_clk_get_range,
	.clk_get_val = scpi_clk_get_val,
	.clk_set_val = scpi_clk_set_val,
	.dvfs_get_idx = scpi_dvfs_get_idx,
	.dvfs_set_idx = scpi_dvfs_set_idx,
	.dvfs_get_info = scpi_dvfs_get_info,
	.sensor_get_capability = scpi_sensor_get_capability,
	.sensor_get_info = scpi_sensor_get_info,
	.sensor_get_value = scpi_sensor_get_value,
};

struct scpi_ops *get_scpi_ops(void)
{
	return scpi_info ? scpi_info->scpi_ops : NULL;
}
EXPORT_SYMBOL_GPL(get_scpi_ops);

static int scpi_init_versions(struct scpi_drvinfo *info)
{
	int ret;
	struct scp_capabilities caps;

	ret = scpi_send_message(SCPI_CMD_SCPI_CAPABILITIES, NULL, 0,
				&caps, sizeof(caps));
	if (!ret) {
		info->protocol_version = le32_to_cpu(caps.protocol_version);
		info->firmware_version = le32_to_cpu(caps.platform_version);
	}
	return ret;
}

static ssize_t protocol_version_show(struct device *dev,
				     struct device_attribute *attr, char *buf)
{
	struct scpi_drvinfo *scpi_info = dev_get_drvdata(dev);

	return sprintf(buf, "%d.%d\n",
		       PROTOCOL_REV_MAJOR(scpi_info->protocol_version),
		       PROTOCOL_REV_MINOR(scpi_info->protocol_version));
}
static DEVICE_ATTR_RO(protocol_version);

static ssize_t firmware_version_show(struct device *dev,
				     struct device_attribute *attr, char *buf)
{
	struct scpi_drvinfo *scpi_info = dev_get_drvdata(dev);

	return sprintf(buf, "%d.%d.%d\n",
		       FW_REV_MAJOR(scpi_info->firmware_version),
		       FW_REV_MINOR(scpi_info->firmware_version),
		       FW_REV_PATCH(scpi_info->firmware_version));
}
static DEVICE_ATTR_RO(firmware_version);

static struct attribute *versions_attrs[] = {
	&dev_attr_firmware_version.attr,
	&dev_attr_protocol_version.attr,
	NULL,
};
ATTRIBUTE_GROUPS(versions);

static void
scpi_free_channels(struct device *dev, struct scpi_chan *pchan, int count)
{
	int i;

	for (i = 0; i < count && pchan->chan; i++, pchan++) {
		mbox_free_channel(pchan->chan);
		devm_kfree(dev, pchan->xfers);
		devm_iounmap(dev, pchan->rx_payload);
	}
}

static int scpi_remove(struct platform_device *pdev)
{
	int i;
	struct device *dev = &pdev->dev;
	struct scpi_drvinfo *info = platform_get_drvdata(pdev);

	scpi_info = NULL; /* stop exporting SCPI ops through get_scpi_ops */

	of_platform_depopulate(dev);
	sysfs_remove_groups(&dev->kobj, versions_groups);
	scpi_free_channels(dev, info->channels, info->num_chans);
	platform_set_drvdata(pdev, NULL);

	for (i = 0; i < MAX_DVFS_DOMAINS && info->dvfs[i]; i++) {
		kfree(info->dvfs[i]->opps);
		kfree(info->dvfs[i]);
	}
	devm_kfree(dev, info->channels);
	devm_kfree(dev, info);

	return 0;
}

#define MAX_SCPI_XFERS		10
static int scpi_alloc_xfer_list(struct device *dev, struct scpi_chan *ch)
{
	int i;
	struct scpi_xfer *xfers;

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

	ch->xfers = xfers;
	for (i = 0; i < MAX_SCPI_XFERS; i++, xfers++)
		list_add_tail(&xfers->node, &ch->xfers_list);
	return 0;
}

static int scpi_probe(struct platform_device *pdev)
{
	int count, idx, ret;
	struct resource res;
	struct scpi_chan *scpi_chan;
	struct device *dev = &pdev->dev;
	struct device_node *np = dev->of_node;

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

	count = of_count_phandle_with_args(np, "mboxes", "#mbox-cells");
	if (count < 0) {
		dev_err(dev, "no mboxes property in '%s'\n", np->full_name);
		return -ENODEV;
	}

	scpi_chan = devm_kcalloc(dev, count, sizeof(*scpi_chan), GFP_KERNEL);
	if (!scpi_chan)
		return -ENOMEM;

	for (idx = 0; idx < count; idx++) {
		resource_size_t size;
		struct scpi_chan *pchan = scpi_chan + idx;
		struct mbox_client *cl = &pchan->cl;
		struct device_node *shmem = of_parse_phandle(np, "shmem", idx);

		if (of_address_to_resource(shmem, 0, &res)) {
			dev_err(dev, "failed to get SCPI payload mem resource\n");
			ret = -EINVAL;
			goto err;
		}

		size = resource_size(&res);
		pchan->rx_payload = devm_ioremap(dev, res.start, size);
		if (!pchan->rx_payload) {
			dev_err(dev, "failed to ioremap SCPI payload\n");
			ret = -EADDRNOTAVAIL;
			goto err;
		}
		pchan->tx_payload = pchan->rx_payload + (size >> 1);

		cl->dev = dev;
		cl->rx_callback = scpi_handle_remote_msg;
		cl->tx_prepare = scpi_tx_prepare;
		cl->tx_block = true;
		cl->tx_tout = 20;
		cl->knows_txdone = false; /* controller can't ack */

		INIT_LIST_HEAD(&pchan->rx_pending);
		INIT_LIST_HEAD(&pchan->xfers_list);
		spin_lock_init(&pchan->rx_lock);
		mutex_init(&pchan->xfers_lock);

		ret = scpi_alloc_xfer_list(dev, pchan);
		if (!ret) {
			pchan->chan = mbox_request_channel(cl, idx);
			if (!IS_ERR(pchan->chan))
				continue;
			ret = PTR_ERR(pchan->chan);
			if (ret != -EPROBE_DEFER)
				dev_err(dev, "failed to get channel%d err %d\n",
					idx, ret);
		}
err:
		scpi_free_channels(dev, scpi_chan, idx);
		scpi_info = NULL;
		return ret;
	}

	scpi_info->channels = scpi_chan;
	scpi_info->num_chans = count;
	platform_set_drvdata(pdev, scpi_info);

	ret = scpi_init_versions(scpi_info);
	if (ret) {
		dev_err(dev, "incorrect or no SCP firmware found\n");
		scpi_remove(pdev);
		return ret;
	}

	_dev_info(dev, "SCP Protocol %d.%d Firmware %d.%d.%d version\n",
		  PROTOCOL_REV_MAJOR(scpi_info->protocol_version),
		  PROTOCOL_REV_MINOR(scpi_info->protocol_version),
		  FW_REV_MAJOR(scpi_info->firmware_version),
		  FW_REV_MINOR(scpi_info->firmware_version),
		  FW_REV_PATCH(scpi_info->firmware_version));
	scpi_info->scpi_ops = &scpi_ops;

	ret = sysfs_create_groups(&dev->kobj, versions_groups);
	if (ret)
		dev_err(dev, "unable to create sysfs version group\n");

	return of_platform_populate(dev->of_node, NULL, NULL, dev);
}

static const struct of_device_id scpi_of_match[] = {
	{.compatible = "arm,scpi"},
	{},
};

MODULE_DEVICE_TABLE(of, scpi_of_match);

static struct platform_driver scpi_driver = {
	.driver = {
		.name = "scpi_protocol",
		.of_match_table = scpi_of_match,
	},
	.probe = scpi_probe,
	.remove = scpi_remove,
};
module_platform_driver(scpi_driver);

MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
MODULE_DESCRIPTION("ARM SCPI mailbox protocol driver");
MODULE_LICENSE("GPL v2");