Training courses

Kernel and Embedded Linux

Bootlin training courses

Embedded Linux, kernel,
Yocto Project, Buildroot, real-time,
graphics, boot time, debugging...

Bootlin logo

Elixir Cross Referencer

  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
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * APM X-Gene SoC Hardware Monitoring Driver
 *
 * Copyright (c) 2016, Applied Micro Circuits Corporation
 * Author: Loc Ho <lho@apm.com>
 *         Hoan Tran <hotran@apm.com>
 *
 * This driver provides the following features:
 *  - Retrieve CPU total power (uW)
 *  - Retrieve IO total power (uW)
 *  - Retrieve SoC temperature (milli-degree C) and alarm
 */
#include <linux/acpi.h>
#include <linux/dma-mapping.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/io.h>
#include <linux/interrupt.h>
#include <linux/kfifo.h>
#include <linux/mailbox_controller.h>
#include <linux/mailbox_client.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>

#include <acpi/pcc.h>

/* SLIMpro message defines */
#define MSG_TYPE_DBG			0
#define MSG_TYPE_ERR			7
#define MSG_TYPE_PWRMGMT		9

#define MSG_TYPE(v)			(((v) & 0xF0000000) >> 28)
#define MSG_TYPE_SET(v)			(((v) << 28) & 0xF0000000)
#define MSG_SUBTYPE(v)			(((v) & 0x0F000000) >> 24)
#define MSG_SUBTYPE_SET(v)		(((v) << 24) & 0x0F000000)

#define DBG_SUBTYPE_SENSOR_READ		4
#define SENSOR_RD_MSG			0x04FFE902
#define SENSOR_RD_EN_ADDR(a)		((a) & 0x000FFFFF)
#define PMD_PWR_REG			0x20
#define PMD_PWR_MW_REG			0x26
#define SOC_PWR_REG			0x21
#define SOC_PWR_MW_REG			0x27
#define SOC_TEMP_REG			0x10

#define TEMP_NEGATIVE_BIT		8
#define SENSOR_INVALID_DATA		BIT(15)

#define PWRMGMT_SUBTYPE_TPC		1
#define TPC_ALARM			2
#define TPC_GET_ALARM			3
#define TPC_CMD(v)			(((v) & 0x00FF0000) >> 16)
#define TPC_CMD_SET(v)			(((v) << 16) & 0x00FF0000)
#define TPC_EN_MSG(hndl, cmd, type) \
	(MSG_TYPE_SET(MSG_TYPE_PWRMGMT) | \
	MSG_SUBTYPE_SET(hndl) | TPC_CMD_SET(cmd) | type)

/* PCC defines */
#define PCC_SIGNATURE_MASK		0x50424300
#define PCCC_GENERATE_DB_INT		BIT(15)
#define PCCS_CMD_COMPLETE		BIT(0)
#define PCCS_SCI_DOORBEL		BIT(1)
#define PCCS_PLATFORM_NOTIFICATION	BIT(3)
/*
 * Arbitrary retries in case the remote processor is slow to respond
 * to PCC commands
 */
#define PCC_NUM_RETRIES			500

#define ASYNC_MSG_FIFO_SIZE		16
#define MBOX_OP_TIMEOUTMS		1000

#define WATT_TO_mWATT(x)		((x) * 1000)
#define mWATT_TO_uWATT(x)		((x) * 1000)
#define CELSIUS_TO_mCELSIUS(x)		((x) * 1000)

#define to_xgene_hwmon_dev(cl)		\
	container_of(cl, struct xgene_hwmon_dev, mbox_client)

enum xgene_hwmon_version {
	XGENE_HWMON_V1 = 0,
	XGENE_HWMON_V2 = 1,
};

struct slimpro_resp_msg {
	u32 msg;
	u32 param1;
	u32 param2;
} __packed;

struct xgene_hwmon_dev {
	struct device		*dev;
	struct mbox_chan	*mbox_chan;
	struct mbox_client	mbox_client;
	int			mbox_idx;

	spinlock_t		kfifo_lock;
	struct mutex		rd_mutex;
	struct completion	rd_complete;
	int			resp_pending;
	struct slimpro_resp_msg sync_msg;

	struct work_struct	workq;
	struct kfifo_rec_ptr_1	async_msg_fifo;

	struct device		*hwmon_dev;
	bool			temp_critical_alarm;

	phys_addr_t		comm_base_addr;
	void			*pcc_comm_addr;
	u64			usecs_lat;
};

/*
 * This function tests and clears a bitmask then returns its old value
 */
static u16 xgene_word_tst_and_clr(u16 *addr, u16 mask)
{
	u16 ret, val;

	val = le16_to_cpu(READ_ONCE(*addr));
	ret = val & mask;
	val &= ~mask;
	WRITE_ONCE(*addr, cpu_to_le16(val));

	return ret;
}

static int xgene_hwmon_pcc_rd(struct xgene_hwmon_dev *ctx, u32 *msg)
{
	struct acpi_pcct_shared_memory *generic_comm_base = ctx->pcc_comm_addr;
	u32 *ptr = (void *)(generic_comm_base + 1);
	int rc, i;
	u16 val;

	mutex_lock(&ctx->rd_mutex);
	init_completion(&ctx->rd_complete);
	ctx->resp_pending = true;

	/* Write signature for subspace */
	WRITE_ONCE(generic_comm_base->signature,
		   cpu_to_le32(PCC_SIGNATURE_MASK | ctx->mbox_idx));

	/* Write to the shared command region */
	WRITE_ONCE(generic_comm_base->command,
		   cpu_to_le16(MSG_TYPE(msg[0]) | PCCC_GENERATE_DB_INT));

	/* Flip CMD COMPLETE bit */
	val = le16_to_cpu(READ_ONCE(generic_comm_base->status));
	val &= ~PCCS_CMD_COMPLETE;
	WRITE_ONCE(generic_comm_base->status, cpu_to_le16(val));

	/* Copy the message to the PCC comm space */
	for (i = 0; i < sizeof(struct slimpro_resp_msg) / 4; i++)
		WRITE_ONCE(ptr[i], cpu_to_le32(msg[i]));

	/* Ring the doorbell */
	rc = mbox_send_message(ctx->mbox_chan, msg);
	if (rc < 0) {
		dev_err(ctx->dev, "Mailbox send error %d\n", rc);
		goto err;
	}
	if (!wait_for_completion_timeout(&ctx->rd_complete,
					 usecs_to_jiffies(ctx->usecs_lat))) {
		dev_err(ctx->dev, "Mailbox operation timed out\n");
		rc = -ETIMEDOUT;
		goto err;
	}

	/* Check for error message */
	if (MSG_TYPE(ctx->sync_msg.msg) == MSG_TYPE_ERR) {
		rc = -EINVAL;
		goto err;
	}

	msg[0] = ctx->sync_msg.msg;
	msg[1] = ctx->sync_msg.param1;
	msg[2] = ctx->sync_msg.param2;

err:
	mbox_chan_txdone(ctx->mbox_chan, 0);
	ctx->resp_pending = false;
	mutex_unlock(&ctx->rd_mutex);
	return rc;
}

static int xgene_hwmon_rd(struct xgene_hwmon_dev *ctx, u32 *msg)
{
	int rc;

	mutex_lock(&ctx->rd_mutex);
	init_completion(&ctx->rd_complete);
	ctx->resp_pending = true;

	rc = mbox_send_message(ctx->mbox_chan, msg);
	if (rc < 0) {
		dev_err(ctx->dev, "Mailbox send error %d\n", rc);
		goto err;
	}

	if (!wait_for_completion_timeout(&ctx->rd_complete,
					 msecs_to_jiffies(MBOX_OP_TIMEOUTMS))) {
		dev_err(ctx->dev, "Mailbox operation timed out\n");
		rc = -ETIMEDOUT;
		goto err;
	}

	/* Check for error message */
	if (MSG_TYPE(ctx->sync_msg.msg) == MSG_TYPE_ERR) {
		rc = -EINVAL;
		goto err;
	}

	msg[0] = ctx->sync_msg.msg;
	msg[1] = ctx->sync_msg.param1;
	msg[2] = ctx->sync_msg.param2;

err:
	ctx->resp_pending = false;
	mutex_unlock(&ctx->rd_mutex);
	return rc;
}

static int xgene_hwmon_reg_map_rd(struct xgene_hwmon_dev *ctx, u32 addr,
				  u32 *data)
{
	u32 msg[3];
	int rc;

	msg[0] = SENSOR_RD_MSG;
	msg[1] = SENSOR_RD_EN_ADDR(addr);
	msg[2] = 0;

	if (acpi_disabled)
		rc = xgene_hwmon_rd(ctx, msg);
	else
		rc = xgene_hwmon_pcc_rd(ctx, msg);

	if (rc < 0)
		return rc;

	/*
	 * Check if sensor data is valid.
	 */
	if (msg[1] & SENSOR_INVALID_DATA)
		return -ENODATA;

	*data = msg[1];

	return rc;
}

static int xgene_hwmon_get_notification_msg(struct xgene_hwmon_dev *ctx,
					    u32 *amsg)
{
	u32 msg[3];
	int rc;

	msg[0] = TPC_EN_MSG(PWRMGMT_SUBTYPE_TPC, TPC_GET_ALARM, 0);
	msg[1] = 0;
	msg[2] = 0;

	rc = xgene_hwmon_pcc_rd(ctx, msg);
	if (rc < 0)
		return rc;

	amsg[0] = msg[0];
	amsg[1] = msg[1];
	amsg[2] = msg[2];

	return rc;
}

static int xgene_hwmon_get_cpu_pwr(struct xgene_hwmon_dev *ctx, u32 *val)
{
	u32 watt, mwatt;
	int rc;

	rc = xgene_hwmon_reg_map_rd(ctx, PMD_PWR_REG, &watt);
	if (rc < 0)
		return rc;

	rc = xgene_hwmon_reg_map_rd(ctx, PMD_PWR_MW_REG, &mwatt);
	if (rc < 0)
		return rc;

	*val = WATT_TO_mWATT(watt) + mwatt;
	return 0;
}

static int xgene_hwmon_get_io_pwr(struct xgene_hwmon_dev *ctx, u32 *val)
{
	u32 watt, mwatt;
	int rc;

	rc = xgene_hwmon_reg_map_rd(ctx, SOC_PWR_REG, &watt);
	if (rc < 0)
		return rc;

	rc = xgene_hwmon_reg_map_rd(ctx, SOC_PWR_MW_REG, &mwatt);
	if (rc < 0)
		return rc;

	*val = WATT_TO_mWATT(watt) + mwatt;
	return 0;
}

static int xgene_hwmon_get_temp(struct xgene_hwmon_dev *ctx, u32 *val)
{
	return xgene_hwmon_reg_map_rd(ctx, SOC_TEMP_REG, val);
}

/*
 * Sensor temperature/power functions
 */
static ssize_t temp1_input_show(struct device *dev,
				struct device_attribute *attr,
				char *buf)
{
	struct xgene_hwmon_dev *ctx = dev_get_drvdata(dev);
	int rc, temp;
	u32 val;

	rc = xgene_hwmon_get_temp(ctx, &val);
	if (rc < 0)
		return rc;

	temp = sign_extend32(val, TEMP_NEGATIVE_BIT);

	return snprintf(buf, PAGE_SIZE, "%d\n", CELSIUS_TO_mCELSIUS(temp));
}

static ssize_t temp1_label_show(struct device *dev,
				struct device_attribute *attr,
				char *buf)
{
	return snprintf(buf, PAGE_SIZE, "SoC Temperature\n");
}

static ssize_t temp1_critical_alarm_show(struct device *dev,
					 struct device_attribute *devattr,
					 char *buf)
{
	struct xgene_hwmon_dev *ctx = dev_get_drvdata(dev);

	return snprintf(buf, PAGE_SIZE, "%d\n", ctx->temp_critical_alarm);
}

static ssize_t power1_label_show(struct device *dev,
				 struct device_attribute *attr,
				 char *buf)
{
	return snprintf(buf, PAGE_SIZE, "CPU power\n");
}

static ssize_t power2_label_show(struct device *dev,
				 struct device_attribute *attr,
				 char *buf)
{
	return snprintf(buf, PAGE_SIZE, "IO power\n");
}

static ssize_t power1_input_show(struct device *dev,
				 struct device_attribute *attr,
				 char *buf)
{
	struct xgene_hwmon_dev *ctx = dev_get_drvdata(dev);
	u32 val;
	int rc;

	rc = xgene_hwmon_get_cpu_pwr(ctx, &val);
	if (rc < 0)
		return rc;

	return snprintf(buf, PAGE_SIZE, "%u\n", mWATT_TO_uWATT(val));
}

static ssize_t power2_input_show(struct device *dev,
				 struct device_attribute *attr,
				 char *buf)
{
	struct xgene_hwmon_dev *ctx = dev_get_drvdata(dev);
	u32 val;
	int rc;

	rc = xgene_hwmon_get_io_pwr(ctx, &val);
	if (rc < 0)
		return rc;

	return snprintf(buf, PAGE_SIZE, "%u\n", mWATT_TO_uWATT(val));
}

static DEVICE_ATTR_RO(temp1_label);
static DEVICE_ATTR_RO(temp1_input);
static DEVICE_ATTR_RO(temp1_critical_alarm);
static DEVICE_ATTR_RO(power1_label);
static DEVICE_ATTR_RO(power1_input);
static DEVICE_ATTR_RO(power2_label);
static DEVICE_ATTR_RO(power2_input);

static struct attribute *xgene_hwmon_attrs[] = {
	&dev_attr_temp1_label.attr,
	&dev_attr_temp1_input.attr,
	&dev_attr_temp1_critical_alarm.attr,
	&dev_attr_power1_label.attr,
	&dev_attr_power1_input.attr,
	&dev_attr_power2_label.attr,
	&dev_attr_power2_input.attr,
	NULL,
};

ATTRIBUTE_GROUPS(xgene_hwmon);

static int xgene_hwmon_tpc_alarm(struct xgene_hwmon_dev *ctx,
				 struct slimpro_resp_msg *amsg)
{
	ctx->temp_critical_alarm = !!amsg->param2;
	sysfs_notify(&ctx->dev->kobj, NULL, "temp1_critical_alarm");

	return 0;
}

static void xgene_hwmon_process_pwrmsg(struct xgene_hwmon_dev *ctx,
				       struct slimpro_resp_msg *amsg)
{
	if ((MSG_SUBTYPE(amsg->msg) == PWRMGMT_SUBTYPE_TPC) &&
	    (TPC_CMD(amsg->msg) == TPC_ALARM))
		xgene_hwmon_tpc_alarm(ctx, amsg);
}

/*
 * This function is called to process async work queue
 */
static void xgene_hwmon_evt_work(struct work_struct *work)
{
	struct slimpro_resp_msg amsg;
	struct xgene_hwmon_dev *ctx;
	int ret;

	ctx = container_of(work, struct xgene_hwmon_dev, workq);
	while (kfifo_out_spinlocked(&ctx->async_msg_fifo, &amsg,
				    sizeof(struct slimpro_resp_msg),
				    &ctx->kfifo_lock)) {
		/*
		 * If PCC, send a consumer command to Platform to get info
		 * If Slimpro Mailbox, get message from specific FIFO
		 */
		if (!acpi_disabled) {
			ret = xgene_hwmon_get_notification_msg(ctx,
							       (u32 *)&amsg);
			if (ret < 0)
				continue;
		}

		if (MSG_TYPE(amsg.msg) == MSG_TYPE_PWRMGMT)
			xgene_hwmon_process_pwrmsg(ctx, &amsg);
	}
}

static int xgene_hwmon_rx_ready(struct xgene_hwmon_dev *ctx, void *msg)
{
	if (IS_ERR_OR_NULL(ctx->hwmon_dev) && !ctx->resp_pending) {
		/* Enqueue to the FIFO */
		kfifo_in_spinlocked(&ctx->async_msg_fifo, msg,
				    sizeof(struct slimpro_resp_msg),
				    &ctx->kfifo_lock);
		return -ENODEV;
	}

	return 0;
}

/*
 * This function is called when the SLIMpro Mailbox received a message
 */
static void xgene_hwmon_rx_cb(struct mbox_client *cl, void *msg)
{
	struct xgene_hwmon_dev *ctx = to_xgene_hwmon_dev(cl);

	/*
	 * While the driver registers with the mailbox framework, an interrupt
	 * can be pending before the probe function completes its
	 * initialization. If such condition occurs, just queue up the message
	 * as the driver is not ready for servicing the callback.
	 */
	if (xgene_hwmon_rx_ready(ctx, msg) < 0)
		return;

	/*
	 * Response message format:
	 * msg[0] is the return code of the operation
	 * msg[1] is the first parameter word
	 * msg[2] is the second parameter word
	 *
	 * As message only supports dword size, just assign it.
	 */

	/* Check for sync query */
	if (ctx->resp_pending &&
	    ((MSG_TYPE(((u32 *)msg)[0]) == MSG_TYPE_ERR) ||
	     (MSG_TYPE(((u32 *)msg)[0]) == MSG_TYPE_DBG &&
	      MSG_SUBTYPE(((u32 *)msg)[0]) == DBG_SUBTYPE_SENSOR_READ) ||
	     (MSG_TYPE(((u32 *)msg)[0]) == MSG_TYPE_PWRMGMT &&
	      MSG_SUBTYPE(((u32 *)msg)[0]) == PWRMGMT_SUBTYPE_TPC &&
	      TPC_CMD(((u32 *)msg)[0]) == TPC_ALARM))) {
		ctx->sync_msg.msg = ((u32 *)msg)[0];
		ctx->sync_msg.param1 = ((u32 *)msg)[1];
		ctx->sync_msg.param2 = ((u32 *)msg)[2];

		/* Operation waiting for response */
		complete(&ctx->rd_complete);

		return;
	}

	/* Enqueue to the FIFO */
	kfifo_in_spinlocked(&ctx->async_msg_fifo, msg,
			    sizeof(struct slimpro_resp_msg), &ctx->kfifo_lock);
	/* Schedule the bottom handler */
	schedule_work(&ctx->workq);
}

/*
 * This function is called when the PCC Mailbox received a message
 */
static void xgene_hwmon_pcc_rx_cb(struct mbox_client *cl, void *msg)
{
	struct xgene_hwmon_dev *ctx = to_xgene_hwmon_dev(cl);
	struct acpi_pcct_shared_memory *generic_comm_base = ctx->pcc_comm_addr;
	struct slimpro_resp_msg amsg;

	/*
	 * While the driver registers with the mailbox framework, an interrupt
	 * can be pending before the probe function completes its
	 * initialization. If such condition occurs, just queue up the message
	 * as the driver is not ready for servicing the callback.
	 */
	if (xgene_hwmon_rx_ready(ctx, &amsg) < 0)
		return;

	msg = generic_comm_base + 1;
	/* Check if platform sends interrupt */
	if (!xgene_word_tst_and_clr(&generic_comm_base->status,
				    PCCS_SCI_DOORBEL))
		return;

	/*
	 * Response message format:
	 * msg[0] is the return code of the operation
	 * msg[1] is the first parameter word
	 * msg[2] is the second parameter word
	 *
	 * As message only supports dword size, just assign it.
	 */

	/* Check for sync query */
	if (ctx->resp_pending &&
	    ((MSG_TYPE(((u32 *)msg)[0]) == MSG_TYPE_ERR) ||
	     (MSG_TYPE(((u32 *)msg)[0]) == MSG_TYPE_DBG &&
	      MSG_SUBTYPE(((u32 *)msg)[0]) == DBG_SUBTYPE_SENSOR_READ) ||
	     (MSG_TYPE(((u32 *)msg)[0]) == MSG_TYPE_PWRMGMT &&
	      MSG_SUBTYPE(((u32 *)msg)[0]) == PWRMGMT_SUBTYPE_TPC &&
	      TPC_CMD(((u32 *)msg)[0]) == TPC_ALARM))) {
		/* Check if platform completes command */
		if (xgene_word_tst_and_clr(&generic_comm_base->status,
					   PCCS_CMD_COMPLETE)) {
			ctx->sync_msg.msg = ((u32 *)msg)[0];
			ctx->sync_msg.param1 = ((u32 *)msg)[1];
			ctx->sync_msg.param2 = ((u32 *)msg)[2];

			/* Operation waiting for response */
			complete(&ctx->rd_complete);

			return;
		}
	}

	/*
	 * Platform notifies interrupt to OSPM.
	 * OPSM schedules a consumer command to get this information
	 * in a workqueue. Platform must wait until OSPM has issued
	 * a consumer command that serves this notification.
	 */

	/* Enqueue to the FIFO */
	kfifo_in_spinlocked(&ctx->async_msg_fifo, &amsg,
			    sizeof(struct slimpro_resp_msg), &ctx->kfifo_lock);
	/* Schedule the bottom handler */
	schedule_work(&ctx->workq);
}

static void xgene_hwmon_tx_done(struct mbox_client *cl, void *msg, int ret)
{
	if (ret) {
		dev_dbg(cl->dev, "TX did not complete: CMD sent:%x, ret:%d\n",
			*(u16 *)msg, ret);
	} else {
		dev_dbg(cl->dev, "TX completed. CMD sent:%x, ret:%d\n",
			*(u16 *)msg, ret);
	}
}

#ifdef CONFIG_ACPI
static const struct acpi_device_id xgene_hwmon_acpi_match[] = {
	{"APMC0D29", XGENE_HWMON_V1},
	{"APMC0D8A", XGENE_HWMON_V2},
	{},
};
MODULE_DEVICE_TABLE(acpi, xgene_hwmon_acpi_match);
#endif

static int xgene_hwmon_probe(struct platform_device *pdev)
{
	struct xgene_hwmon_dev *ctx;
	struct mbox_client *cl;
	int rc;

	ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
	if (!ctx)
		return -ENOMEM;

	ctx->dev = &pdev->dev;
	platform_set_drvdata(pdev, ctx);
	cl = &ctx->mbox_client;

	spin_lock_init(&ctx->kfifo_lock);
	mutex_init(&ctx->rd_mutex);

	rc = kfifo_alloc(&ctx->async_msg_fifo,
			 sizeof(struct slimpro_resp_msg) * ASYNC_MSG_FIFO_SIZE,
			 GFP_KERNEL);
	if (rc)
		return -ENOMEM;

	INIT_WORK(&ctx->workq, xgene_hwmon_evt_work);

	/* Request mailbox channel */
	cl->dev = &pdev->dev;
	cl->tx_done = xgene_hwmon_tx_done;
	cl->tx_block = false;
	cl->tx_tout = MBOX_OP_TIMEOUTMS;
	cl->knows_txdone = false;
	if (acpi_disabled) {
		cl->rx_callback = xgene_hwmon_rx_cb;
		ctx->mbox_chan = mbox_request_channel(cl, 0);
		if (IS_ERR(ctx->mbox_chan)) {
			dev_err(&pdev->dev,
				"SLIMpro mailbox channel request failed\n");
			rc = -ENODEV;
			goto out_mbox_free;
		}
	} else {
		struct acpi_pcct_hw_reduced *cppc_ss;
		const struct acpi_device_id *acpi_id;
		int version;

		acpi_id = acpi_match_device(pdev->dev.driver->acpi_match_table,
					    &pdev->dev);
		if (!acpi_id)
			return -EINVAL;

		version = (int)acpi_id->driver_data;

		if (device_property_read_u32(&pdev->dev, "pcc-channel",
					     &ctx->mbox_idx)) {
			dev_err(&pdev->dev, "no pcc-channel property\n");
			rc = -ENODEV;
			goto out_mbox_free;
		}

		cl->rx_callback = xgene_hwmon_pcc_rx_cb;
		ctx->mbox_chan = pcc_mbox_request_channel(cl, ctx->mbox_idx);
		if (IS_ERR(ctx->mbox_chan)) {
			dev_err(&pdev->dev,
				"PPC channel request failed\n");
			rc = -ENODEV;
			goto out_mbox_free;
		}

		/*
		 * The PCC mailbox controller driver should
		 * have parsed the PCCT (global table of all
		 * PCC channels) and stored pointers to the
		 * subspace communication region in con_priv.
		 */
		cppc_ss = ctx->mbox_chan->con_priv;
		if (!cppc_ss) {
			dev_err(&pdev->dev, "PPC subspace not found\n");
			rc = -ENODEV;
			goto out;
		}

		if (!ctx->mbox_chan->mbox->txdone_irq) {
			dev_err(&pdev->dev, "PCC IRQ not supported\n");
			rc = -ENODEV;
			goto out;
		}

		/*
		 * This is the shared communication region
		 * for the OS and Platform to communicate over.
		 */
		ctx->comm_base_addr = cppc_ss->base_address;
		if (ctx->comm_base_addr) {
			if (version == XGENE_HWMON_V2)
				ctx->pcc_comm_addr = (void __force *)ioremap(
							ctx->comm_base_addr,
							cppc_ss->length);
			else
				ctx->pcc_comm_addr = memremap(
							ctx->comm_base_addr,
							cppc_ss->length,
							MEMREMAP_WB);
		} else {
			dev_err(&pdev->dev, "Failed to get PCC comm region\n");
			rc = -ENODEV;
			goto out;
		}

		if (!ctx->pcc_comm_addr) {
			dev_err(&pdev->dev,
				"Failed to ioremap PCC comm region\n");
			rc = -ENOMEM;
			goto out;
		}

		/*
		 * cppc_ss->latency is just a Nominal value. In reality
		 * the remote processor could be much slower to reply.
		 * So add an arbitrary amount of wait on top of Nominal.
		 */
		ctx->usecs_lat = PCC_NUM_RETRIES * cppc_ss->latency;
	}

	ctx->hwmon_dev = hwmon_device_register_with_groups(ctx->dev,
							   "apm_xgene",
							   ctx,
							   xgene_hwmon_groups);
	if (IS_ERR(ctx->hwmon_dev)) {
		dev_err(&pdev->dev, "Failed to register HW monitor device\n");
		rc = PTR_ERR(ctx->hwmon_dev);
		goto out;
	}

	/*
	 * Schedule the bottom handler if there is a pending message.
	 */
	schedule_work(&ctx->workq);

	dev_info(&pdev->dev, "APM X-Gene SoC HW monitor driver registered\n");

	return 0;

out:
	if (acpi_disabled)
		mbox_free_channel(ctx->mbox_chan);
	else
		pcc_mbox_free_channel(ctx->mbox_chan);
out_mbox_free:
	kfifo_free(&ctx->async_msg_fifo);

	return rc;
}

static int xgene_hwmon_remove(struct platform_device *pdev)
{
	struct xgene_hwmon_dev *ctx = platform_get_drvdata(pdev);

	hwmon_device_unregister(ctx->hwmon_dev);
	kfifo_free(&ctx->async_msg_fifo);
	if (acpi_disabled)
		mbox_free_channel(ctx->mbox_chan);
	else
		pcc_mbox_free_channel(ctx->mbox_chan);

	return 0;
}

static const struct of_device_id xgene_hwmon_of_match[] = {
	{.compatible = "apm,xgene-slimpro-hwmon"},
	{}
};
MODULE_DEVICE_TABLE(of, xgene_hwmon_of_match);

static struct platform_driver xgene_hwmon_driver __refdata = {
	.probe = xgene_hwmon_probe,
	.remove = xgene_hwmon_remove,
	.driver = {
		.name = "xgene-slimpro-hwmon",
		.of_match_table = xgene_hwmon_of_match,
		.acpi_match_table = ACPI_PTR(xgene_hwmon_acpi_match),
	},
};
module_platform_driver(xgene_hwmon_driver);

MODULE_DESCRIPTION("APM X-Gene SoC hardware monitor");
MODULE_LICENSE("GPL");