xref: /linux/drivers/hwmon/xgene-hwmon.c (revision 3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * APM X-Gene SoC Hardware Monitoring Driver
4  *
5  * Copyright (c) 2016, Applied Micro Circuits Corporation
6  * Author: Loc Ho <lho@apm.com>
7  *         Hoan Tran <hotran@apm.com>
8  *
9  * This driver provides the following features:
10  *  - Retrieve CPU total power (uW)
11  *  - Retrieve IO total power (uW)
12  *  - Retrieve SoC temperature (milli-degree C) and alarm
13  */
14 #include <linux/acpi.h>
15 #include <linux/dma-mapping.h>
16 #include <linux/hwmon.h>
17 #include <linux/hwmon-sysfs.h>
18 #include <linux/io.h>
19 #include <linux/interrupt.h>
20 #include <linux/kfifo.h>
21 #include <linux/mailbox_controller.h>
22 #include <linux/mailbox_client.h>
23 #include <linux/module.h>
24 #include <linux/of.h>
25 #include <linux/platform_device.h>
26 
27 #include <acpi/pcc.h>
28 
29 /* SLIMpro message defines */
30 #define MSG_TYPE_DBG			0
31 #define MSG_TYPE_ERR			7
32 #define MSG_TYPE_PWRMGMT		9
33 
34 #define MSG_TYPE(v)			(((v) & 0xF0000000) >> 28)
35 #define MSG_TYPE_SET(v)			(((v) << 28) & 0xF0000000)
36 #define MSG_SUBTYPE(v)			(((v) & 0x0F000000) >> 24)
37 #define MSG_SUBTYPE_SET(v)		(((v) << 24) & 0x0F000000)
38 
39 #define DBG_SUBTYPE_SENSOR_READ		4
40 #define SENSOR_RD_MSG			0x04FFE902
41 #define SENSOR_RD_EN_ADDR(a)		((a) & 0x000FFFFF)
42 #define PMD_PWR_REG			0x20
43 #define PMD_PWR_MW_REG			0x26
44 #define SOC_PWR_REG			0x21
45 #define SOC_PWR_MW_REG			0x27
46 #define SOC_TEMP_REG			0x10
47 
48 #define TEMP_NEGATIVE_BIT		8
49 #define SENSOR_INVALID_DATA		BIT(15)
50 
51 #define PWRMGMT_SUBTYPE_TPC		1
52 #define TPC_ALARM			2
53 #define TPC_GET_ALARM			3
54 #define TPC_CMD(v)			(((v) & 0x00FF0000) >> 16)
55 #define TPC_CMD_SET(v)			(((v) << 16) & 0x00FF0000)
56 #define TPC_EN_MSG(hndl, cmd, type) \
57 	(MSG_TYPE_SET(MSG_TYPE_PWRMGMT) | \
58 	MSG_SUBTYPE_SET(hndl) | TPC_CMD_SET(cmd) | type)
59 
60 /*
61  * Arbitrary retries in case the remote processor is slow to respond
62  * to PCC commands
63  */
64 #define PCC_NUM_RETRIES			500
65 
66 #define ASYNC_MSG_FIFO_SIZE		16
67 #define MBOX_OP_TIMEOUTMS		1000
68 
69 #define WATT_TO_mWATT(x)		((x) * 1000)
70 #define mWATT_TO_uWATT(x)		((x) * 1000)
71 #define CELSIUS_TO_mCELSIUS(x)		((x) * 1000)
72 
73 #define to_xgene_hwmon_dev(cl)		\
74 	container_of(cl, struct xgene_hwmon_dev, mbox_client)
75 
76 enum xgene_hwmon_version {
77 	XGENE_HWMON_V1 = 0,
78 	XGENE_HWMON_V2 = 1,
79 };
80 
81 struct slimpro_resp_msg {
82 	u32 msg;
83 	u32 param1;
84 	u32 param2;
85 } __packed;
86 
87 struct xgene_hwmon_dev {
88 	struct device		*dev;
89 	struct mbox_chan	*mbox_chan;
90 	struct pcc_mbox_chan	*pcc_chan;
91 	struct mbox_client	mbox_client;
92 	int			mbox_idx;
93 
94 	spinlock_t		kfifo_lock;
95 	struct mutex		rd_mutex;
96 	struct completion	rd_complete;
97 	int			resp_pending;
98 	struct slimpro_resp_msg sync_msg;
99 
100 	struct work_struct	workq;
101 	struct kfifo_rec_ptr_1	async_msg_fifo;
102 
103 	struct device		*hwmon_dev;
104 	bool			temp_critical_alarm;
105 
106 	unsigned int		usecs_lat;
107 };
108 
109 /*
110  * This function tests and clears a bitmask then returns its old value
111  */
112 static u16 xgene_word_tst_and_clr(u16 *addr, u16 mask)
113 {
114 	u16 ret, val;
115 
116 	val = le16_to_cpu(READ_ONCE(*addr));
117 	ret = val & mask;
118 	val &= ~mask;
119 	WRITE_ONCE(*addr, cpu_to_le16(val));
120 
121 	return ret;
122 }
123 
124 static int xgene_hwmon_pcc_rd(struct xgene_hwmon_dev *ctx, u32 *msg)
125 {
126 	struct acpi_pcct_shared_memory __iomem *generic_comm_base =
127 							ctx->pcc_chan->shmem;
128 	u32 *ptr = (void *)(generic_comm_base + 1);
129 	int rc, i;
130 	u16 val;
131 
132 	mutex_lock(&ctx->rd_mutex);
133 	init_completion(&ctx->rd_complete);
134 	ctx->resp_pending = true;
135 
136 	/* Write to the shared command region */
137 	WRITE_ONCE(generic_comm_base->command,
138 		   cpu_to_le16(MSG_TYPE(msg[0]) | PCC_CMD_GENERATE_DB_INTR));
139 
140 	/* Flip CMD COMPLETE bit */
141 	val = le16_to_cpu(READ_ONCE(generic_comm_base->status));
142 	val &= ~PCC_STATUS_CMD_COMPLETE;
143 	WRITE_ONCE(generic_comm_base->status, cpu_to_le16(val));
144 
145 	/* Copy the message to the PCC comm space */
146 	for (i = 0; i < sizeof(struct slimpro_resp_msg) / 4; i++)
147 		WRITE_ONCE(ptr[i], cpu_to_le32(msg[i]));
148 
149 	/* Ring the doorbell */
150 	rc = mbox_send_message(ctx->mbox_chan, msg);
151 	if (rc < 0) {
152 		dev_err(ctx->dev, "Mailbox send error %d\n", rc);
153 		goto err;
154 	}
155 	if (!wait_for_completion_timeout(&ctx->rd_complete,
156 					 usecs_to_jiffies(ctx->usecs_lat))) {
157 		dev_err(ctx->dev, "Mailbox operation timed out\n");
158 		rc = -ETIMEDOUT;
159 		goto err;
160 	}
161 
162 	/* Check for error message */
163 	if (MSG_TYPE(ctx->sync_msg.msg) == MSG_TYPE_ERR) {
164 		rc = -EINVAL;
165 		goto err;
166 	}
167 
168 	msg[0] = ctx->sync_msg.msg;
169 	msg[1] = ctx->sync_msg.param1;
170 	msg[2] = ctx->sync_msg.param2;
171 
172 err:
173 	mbox_chan_txdone(ctx->mbox_chan, 0);
174 	ctx->resp_pending = false;
175 	mutex_unlock(&ctx->rd_mutex);
176 	return rc;
177 }
178 
179 static int xgene_hwmon_rd(struct xgene_hwmon_dev *ctx, u32 *msg)
180 {
181 	int rc;
182 
183 	mutex_lock(&ctx->rd_mutex);
184 	init_completion(&ctx->rd_complete);
185 	ctx->resp_pending = true;
186 
187 	rc = mbox_send_message(ctx->mbox_chan, msg);
188 	if (rc < 0) {
189 		dev_err(ctx->dev, "Mailbox send error %d\n", rc);
190 		goto err;
191 	}
192 
193 	if (!wait_for_completion_timeout(&ctx->rd_complete,
194 					 msecs_to_jiffies(MBOX_OP_TIMEOUTMS))) {
195 		dev_err(ctx->dev, "Mailbox operation timed out\n");
196 		rc = -ETIMEDOUT;
197 		goto err;
198 	}
199 
200 	/* Check for error message */
201 	if (MSG_TYPE(ctx->sync_msg.msg) == MSG_TYPE_ERR) {
202 		rc = -EINVAL;
203 		goto err;
204 	}
205 
206 	msg[0] = ctx->sync_msg.msg;
207 	msg[1] = ctx->sync_msg.param1;
208 	msg[2] = ctx->sync_msg.param2;
209 
210 err:
211 	ctx->resp_pending = false;
212 	mutex_unlock(&ctx->rd_mutex);
213 	return rc;
214 }
215 
216 static int xgene_hwmon_reg_map_rd(struct xgene_hwmon_dev *ctx, u32 addr,
217 				  u32 *data)
218 {
219 	u32 msg[3];
220 	int rc;
221 
222 	msg[0] = SENSOR_RD_MSG;
223 	msg[1] = SENSOR_RD_EN_ADDR(addr);
224 	msg[2] = 0;
225 
226 	if (acpi_disabled)
227 		rc = xgene_hwmon_rd(ctx, msg);
228 	else
229 		rc = xgene_hwmon_pcc_rd(ctx, msg);
230 
231 	if (rc < 0)
232 		return rc;
233 
234 	/*
235 	 * Check if sensor data is valid.
236 	 */
237 	if (msg[1] & SENSOR_INVALID_DATA)
238 		return -ENODATA;
239 
240 	*data = msg[1];
241 
242 	return rc;
243 }
244 
245 static int xgene_hwmon_get_notification_msg(struct xgene_hwmon_dev *ctx,
246 					    u32 *amsg)
247 {
248 	u32 msg[3];
249 	int rc;
250 
251 	msg[0] = TPC_EN_MSG(PWRMGMT_SUBTYPE_TPC, TPC_GET_ALARM, 0);
252 	msg[1] = 0;
253 	msg[2] = 0;
254 
255 	rc = xgene_hwmon_pcc_rd(ctx, msg);
256 	if (rc < 0)
257 		return rc;
258 
259 	amsg[0] = msg[0];
260 	amsg[1] = msg[1];
261 	amsg[2] = msg[2];
262 
263 	return rc;
264 }
265 
266 static int xgene_hwmon_get_cpu_pwr(struct xgene_hwmon_dev *ctx, u32 *val)
267 {
268 	u32 watt, mwatt;
269 	int rc;
270 
271 	rc = xgene_hwmon_reg_map_rd(ctx, PMD_PWR_REG, &watt);
272 	if (rc < 0)
273 		return rc;
274 
275 	rc = xgene_hwmon_reg_map_rd(ctx, PMD_PWR_MW_REG, &mwatt);
276 	if (rc < 0)
277 		return rc;
278 
279 	*val = WATT_TO_mWATT(watt) + mwatt;
280 	return 0;
281 }
282 
283 static int xgene_hwmon_get_io_pwr(struct xgene_hwmon_dev *ctx, u32 *val)
284 {
285 	u32 watt, mwatt;
286 	int rc;
287 
288 	rc = xgene_hwmon_reg_map_rd(ctx, SOC_PWR_REG, &watt);
289 	if (rc < 0)
290 		return rc;
291 
292 	rc = xgene_hwmon_reg_map_rd(ctx, SOC_PWR_MW_REG, &mwatt);
293 	if (rc < 0)
294 		return rc;
295 
296 	*val = WATT_TO_mWATT(watt) + mwatt;
297 	return 0;
298 }
299 
300 static int xgene_hwmon_get_temp(struct xgene_hwmon_dev *ctx, u32 *val)
301 {
302 	return xgene_hwmon_reg_map_rd(ctx, SOC_TEMP_REG, val);
303 }
304 
305 /*
306  * Sensor temperature/power functions
307  */
308 static ssize_t temp1_input_show(struct device *dev,
309 				struct device_attribute *attr,
310 				char *buf)
311 {
312 	struct xgene_hwmon_dev *ctx = dev_get_drvdata(dev);
313 	int rc, temp;
314 	u32 val;
315 
316 	rc = xgene_hwmon_get_temp(ctx, &val);
317 	if (rc < 0)
318 		return rc;
319 
320 	temp = sign_extend32(val, TEMP_NEGATIVE_BIT);
321 
322 	return sysfs_emit(buf, "%d\n", CELSIUS_TO_mCELSIUS(temp));
323 }
324 
325 static ssize_t temp1_label_show(struct device *dev,
326 				struct device_attribute *attr,
327 				char *buf)
328 {
329 	return sysfs_emit(buf, "SoC Temperature\n");
330 }
331 
332 static ssize_t temp1_critical_alarm_show(struct device *dev,
333 					 struct device_attribute *devattr,
334 					 char *buf)
335 {
336 	struct xgene_hwmon_dev *ctx = dev_get_drvdata(dev);
337 
338 	return sysfs_emit(buf, "%d\n", ctx->temp_critical_alarm);
339 }
340 
341 static ssize_t power1_label_show(struct device *dev,
342 				 struct device_attribute *attr,
343 				 char *buf)
344 {
345 	return sysfs_emit(buf, "CPU power\n");
346 }
347 
348 static ssize_t power2_label_show(struct device *dev,
349 				 struct device_attribute *attr,
350 				 char *buf)
351 {
352 	return sysfs_emit(buf, "IO power\n");
353 }
354 
355 static ssize_t power1_input_show(struct device *dev,
356 				 struct device_attribute *attr,
357 				 char *buf)
358 {
359 	struct xgene_hwmon_dev *ctx = dev_get_drvdata(dev);
360 	u32 val;
361 	int rc;
362 
363 	rc = xgene_hwmon_get_cpu_pwr(ctx, &val);
364 	if (rc < 0)
365 		return rc;
366 
367 	return sysfs_emit(buf, "%u\n", mWATT_TO_uWATT(val));
368 }
369 
370 static ssize_t power2_input_show(struct device *dev,
371 				 struct device_attribute *attr,
372 				 char *buf)
373 {
374 	struct xgene_hwmon_dev *ctx = dev_get_drvdata(dev);
375 	u32 val;
376 	int rc;
377 
378 	rc = xgene_hwmon_get_io_pwr(ctx, &val);
379 	if (rc < 0)
380 		return rc;
381 
382 	return sysfs_emit(buf, "%u\n", mWATT_TO_uWATT(val));
383 }
384 
385 static DEVICE_ATTR_RO(temp1_label);
386 static DEVICE_ATTR_RO(temp1_input);
387 static DEVICE_ATTR_RO(temp1_critical_alarm);
388 static DEVICE_ATTR_RO(power1_label);
389 static DEVICE_ATTR_RO(power1_input);
390 static DEVICE_ATTR_RO(power2_label);
391 static DEVICE_ATTR_RO(power2_input);
392 
393 static struct attribute *xgene_hwmon_attrs[] = {
394 	&dev_attr_temp1_label.attr,
395 	&dev_attr_temp1_input.attr,
396 	&dev_attr_temp1_critical_alarm.attr,
397 	&dev_attr_power1_label.attr,
398 	&dev_attr_power1_input.attr,
399 	&dev_attr_power2_label.attr,
400 	&dev_attr_power2_input.attr,
401 	NULL,
402 };
403 
404 ATTRIBUTE_GROUPS(xgene_hwmon);
405 
406 static int xgene_hwmon_tpc_alarm(struct xgene_hwmon_dev *ctx,
407 				 struct slimpro_resp_msg *amsg)
408 {
409 	ctx->temp_critical_alarm = !!amsg->param2;
410 	sysfs_notify(&ctx->dev->kobj, NULL, "temp1_critical_alarm");
411 
412 	return 0;
413 }
414 
415 static void xgene_hwmon_process_pwrmsg(struct xgene_hwmon_dev *ctx,
416 				       struct slimpro_resp_msg *amsg)
417 {
418 	if ((MSG_SUBTYPE(amsg->msg) == PWRMGMT_SUBTYPE_TPC) &&
419 	    (TPC_CMD(amsg->msg) == TPC_ALARM))
420 		xgene_hwmon_tpc_alarm(ctx, amsg);
421 }
422 
423 /*
424  * This function is called to process async work queue
425  */
426 static void xgene_hwmon_evt_work(struct work_struct *work)
427 {
428 	struct slimpro_resp_msg amsg;
429 	struct xgene_hwmon_dev *ctx;
430 	int ret;
431 
432 	ctx = container_of(work, struct xgene_hwmon_dev, workq);
433 	while (kfifo_out_spinlocked(&ctx->async_msg_fifo, &amsg,
434 				    sizeof(struct slimpro_resp_msg),
435 				    &ctx->kfifo_lock)) {
436 		/*
437 		 * If PCC, send a consumer command to Platform to get info
438 		 * If Slimpro Mailbox, get message from specific FIFO
439 		 */
440 		if (!acpi_disabled) {
441 			ret = xgene_hwmon_get_notification_msg(ctx,
442 							       (u32 *)&amsg);
443 			if (ret < 0)
444 				continue;
445 		}
446 
447 		if (MSG_TYPE(amsg.msg) == MSG_TYPE_PWRMGMT)
448 			xgene_hwmon_process_pwrmsg(ctx, &amsg);
449 	}
450 }
451 
452 static int xgene_hwmon_rx_ready(struct xgene_hwmon_dev *ctx, void *msg)
453 {
454 	if (IS_ERR_OR_NULL(ctx->hwmon_dev) && !ctx->resp_pending) {
455 		/* Enqueue to the FIFO */
456 		kfifo_in_spinlocked(&ctx->async_msg_fifo, msg,
457 				    sizeof(struct slimpro_resp_msg),
458 				    &ctx->kfifo_lock);
459 		return -ENODEV;
460 	}
461 
462 	return 0;
463 }
464 
465 /*
466  * This function is called when the SLIMpro Mailbox received a message
467  */
468 static void xgene_hwmon_rx_cb(struct mbox_client *cl, void *msg)
469 {
470 	struct xgene_hwmon_dev *ctx = to_xgene_hwmon_dev(cl);
471 
472 	/*
473 	 * While the driver registers with the mailbox framework, an interrupt
474 	 * can be pending before the probe function completes its
475 	 * initialization. If such condition occurs, just queue up the message
476 	 * as the driver is not ready for servicing the callback.
477 	 */
478 	if (xgene_hwmon_rx_ready(ctx, msg) < 0)
479 		return;
480 
481 	/*
482 	 * Response message format:
483 	 * msg[0] is the return code of the operation
484 	 * msg[1] is the first parameter word
485 	 * msg[2] is the second parameter word
486 	 *
487 	 * As message only supports dword size, just assign it.
488 	 */
489 
490 	/* Check for sync query */
491 	if (ctx->resp_pending &&
492 	    ((MSG_TYPE(((u32 *)msg)[0]) == MSG_TYPE_ERR) ||
493 	     (MSG_TYPE(((u32 *)msg)[0]) == MSG_TYPE_DBG &&
494 	      MSG_SUBTYPE(((u32 *)msg)[0]) == DBG_SUBTYPE_SENSOR_READ) ||
495 	     (MSG_TYPE(((u32 *)msg)[0]) == MSG_TYPE_PWRMGMT &&
496 	      MSG_SUBTYPE(((u32 *)msg)[0]) == PWRMGMT_SUBTYPE_TPC &&
497 	      TPC_CMD(((u32 *)msg)[0]) == TPC_ALARM))) {
498 		ctx->sync_msg.msg = ((u32 *)msg)[0];
499 		ctx->sync_msg.param1 = ((u32 *)msg)[1];
500 		ctx->sync_msg.param2 = ((u32 *)msg)[2];
501 
502 		/* Operation waiting for response */
503 		complete(&ctx->rd_complete);
504 
505 		return;
506 	}
507 
508 	/* Enqueue to the FIFO */
509 	kfifo_in_spinlocked(&ctx->async_msg_fifo, msg,
510 			    sizeof(struct slimpro_resp_msg), &ctx->kfifo_lock);
511 	/* Schedule the bottom handler */
512 	schedule_work(&ctx->workq);
513 }
514 
515 /*
516  * This function is called when the PCC Mailbox received a message
517  */
518 static void xgene_hwmon_pcc_rx_cb(struct mbox_client *cl, void *msg)
519 {
520 	struct xgene_hwmon_dev *ctx = to_xgene_hwmon_dev(cl);
521 	struct acpi_pcct_shared_memory __iomem *generic_comm_base =
522 							ctx->pcc_chan->shmem;
523 	struct slimpro_resp_msg amsg;
524 
525 	/*
526 	 * While the driver registers with the mailbox framework, an interrupt
527 	 * can be pending before the probe function completes its
528 	 * initialization. If such condition occurs, just queue up the message
529 	 * as the driver is not ready for servicing the callback.
530 	 */
531 	if (xgene_hwmon_rx_ready(ctx, &amsg) < 0)
532 		return;
533 
534 	msg = generic_comm_base + 1;
535 	/* Check if platform sends interrupt */
536 	if (!xgene_word_tst_and_clr(&generic_comm_base->status,
537 				    PCC_STATUS_SCI_DOORBELL))
538 		return;
539 
540 	/*
541 	 * Response message format:
542 	 * msg[0] is the return code of the operation
543 	 * msg[1] is the first parameter word
544 	 * msg[2] is the second parameter word
545 	 *
546 	 * As message only supports dword size, just assign it.
547 	 */
548 
549 	/* Check for sync query */
550 	if (ctx->resp_pending &&
551 	    ((MSG_TYPE(((u32 *)msg)[0]) == MSG_TYPE_ERR) ||
552 	     (MSG_TYPE(((u32 *)msg)[0]) == MSG_TYPE_DBG &&
553 	      MSG_SUBTYPE(((u32 *)msg)[0]) == DBG_SUBTYPE_SENSOR_READ) ||
554 	     (MSG_TYPE(((u32 *)msg)[0]) == MSG_TYPE_PWRMGMT &&
555 	      MSG_SUBTYPE(((u32 *)msg)[0]) == PWRMGMT_SUBTYPE_TPC &&
556 	      TPC_CMD(((u32 *)msg)[0]) == TPC_ALARM))) {
557 		/* Check if platform completes command */
558 		if (xgene_word_tst_and_clr(&generic_comm_base->status,
559 					   PCC_STATUS_CMD_COMPLETE)) {
560 			ctx->sync_msg.msg = ((u32 *)msg)[0];
561 			ctx->sync_msg.param1 = ((u32 *)msg)[1];
562 			ctx->sync_msg.param2 = ((u32 *)msg)[2];
563 
564 			/* Operation waiting for response */
565 			complete(&ctx->rd_complete);
566 
567 			return;
568 		}
569 	}
570 
571 	/*
572 	 * Platform notifies interrupt to OSPM.
573 	 * OPSM schedules a consumer command to get this information
574 	 * in a workqueue. Platform must wait until OSPM has issued
575 	 * a consumer command that serves this notification.
576 	 */
577 
578 	/* Enqueue to the FIFO */
579 	kfifo_in_spinlocked(&ctx->async_msg_fifo, &amsg,
580 			    sizeof(struct slimpro_resp_msg), &ctx->kfifo_lock);
581 	/* Schedule the bottom handler */
582 	schedule_work(&ctx->workq);
583 }
584 
585 static void xgene_hwmon_tx_done(struct mbox_client *cl, void *msg, int ret)
586 {
587 	if (ret) {
588 		dev_dbg(cl->dev, "TX did not complete: CMD sent:%x, ret:%d\n",
589 			*(u16 *)msg, ret);
590 	} else {
591 		dev_dbg(cl->dev, "TX completed. CMD sent:%x, ret:%d\n",
592 			*(u16 *)msg, ret);
593 	}
594 }
595 
596 #ifdef CONFIG_ACPI
597 static const struct acpi_device_id xgene_hwmon_acpi_match[] = {
598 	{"APMC0D29", XGENE_HWMON_V1},
599 	{"APMC0D8A", XGENE_HWMON_V2},
600 	{},
601 };
602 MODULE_DEVICE_TABLE(acpi, xgene_hwmon_acpi_match);
603 #endif
604 
605 static int xgene_hwmon_probe(struct platform_device *pdev)
606 {
607 	struct xgene_hwmon_dev *ctx;
608 	struct mbox_client *cl;
609 	int rc;
610 
611 	ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
612 	if (!ctx)
613 		return -ENOMEM;
614 
615 	ctx->dev = &pdev->dev;
616 	platform_set_drvdata(pdev, ctx);
617 	cl = &ctx->mbox_client;
618 
619 	spin_lock_init(&ctx->kfifo_lock);
620 	mutex_init(&ctx->rd_mutex);
621 
622 	rc = kfifo_alloc(&ctx->async_msg_fifo,
623 			 sizeof(struct slimpro_resp_msg) * ASYNC_MSG_FIFO_SIZE,
624 			 GFP_KERNEL);
625 	if (rc)
626 		return -ENOMEM;
627 
628 	INIT_WORK(&ctx->workq, xgene_hwmon_evt_work);
629 
630 	/* Request mailbox channel */
631 	cl->dev = &pdev->dev;
632 	cl->tx_done = xgene_hwmon_tx_done;
633 	cl->tx_block = false;
634 	cl->tx_tout = MBOX_OP_TIMEOUTMS;
635 	cl->knows_txdone = false;
636 	if (acpi_disabled) {
637 		cl->rx_callback = xgene_hwmon_rx_cb;
638 		ctx->mbox_chan = mbox_request_channel(cl, 0);
639 		if (IS_ERR(ctx->mbox_chan)) {
640 			dev_err(&pdev->dev,
641 				"SLIMpro mailbox channel request failed\n");
642 			rc = -ENODEV;
643 			goto out_mbox_free;
644 		}
645 	} else {
646 		struct pcc_mbox_chan *pcc_chan;
647 		const struct acpi_device_id *acpi_id;
648 
649 		acpi_id = acpi_match_device(pdev->dev.driver->acpi_match_table,
650 					    &pdev->dev);
651 		if (!acpi_id) {
652 			rc = -EINVAL;
653 			goto out_mbox_free;
654 		}
655 
656 		if (device_property_read_u32(&pdev->dev, "pcc-channel",
657 					     &ctx->mbox_idx)) {
658 			dev_err(&pdev->dev, "no pcc-channel property\n");
659 			rc = -ENODEV;
660 			goto out_mbox_free;
661 		}
662 
663 		cl->rx_callback = xgene_hwmon_pcc_rx_cb;
664 		pcc_chan = pcc_mbox_request_channel(cl, ctx->mbox_idx);
665 		if (IS_ERR(pcc_chan)) {
666 			dev_err(&pdev->dev,
667 				"PPC channel request failed\n");
668 			rc = -ENODEV;
669 			goto out_mbox_free;
670 		}
671 
672 		ctx->pcc_chan = pcc_chan;
673 		ctx->mbox_chan = pcc_chan->mchan;
674 
675 		if (!ctx->mbox_chan->mbox->txdone_irq) {
676 			dev_err(&pdev->dev, "PCC IRQ not supported\n");
677 			rc = -ENODEV;
678 			goto out;
679 		}
680 
681 		/*
682 		 * pcc_chan->latency is just a Nominal value. In reality
683 		 * the remote processor could be much slower to reply.
684 		 * So add an arbitrary amount of wait on top of Nominal.
685 		 */
686 		ctx->usecs_lat = PCC_NUM_RETRIES * pcc_chan->latency;
687 	}
688 
689 	ctx->hwmon_dev = hwmon_device_register_with_groups(ctx->dev,
690 							   "apm_xgene",
691 							   ctx,
692 							   xgene_hwmon_groups);
693 	if (IS_ERR(ctx->hwmon_dev)) {
694 		dev_err(&pdev->dev, "Failed to register HW monitor device\n");
695 		rc = PTR_ERR(ctx->hwmon_dev);
696 		goto out;
697 	}
698 
699 	/*
700 	 * Schedule the bottom handler if there is a pending message.
701 	 */
702 	schedule_work(&ctx->workq);
703 
704 	dev_info(&pdev->dev, "APM X-Gene SoC HW monitor driver registered\n");
705 
706 	return 0;
707 
708 out:
709 	if (acpi_disabled)
710 		mbox_free_channel(ctx->mbox_chan);
711 	else
712 		pcc_mbox_free_channel(ctx->pcc_chan);
713 out_mbox_free:
714 	kfifo_free(&ctx->async_msg_fifo);
715 
716 	return rc;
717 }
718 
719 static void xgene_hwmon_remove(struct platform_device *pdev)
720 {
721 	struct xgene_hwmon_dev *ctx = platform_get_drvdata(pdev);
722 
723 	cancel_work_sync(&ctx->workq);
724 	hwmon_device_unregister(ctx->hwmon_dev);
725 	kfifo_free(&ctx->async_msg_fifo);
726 	if (acpi_disabled)
727 		mbox_free_channel(ctx->mbox_chan);
728 	else
729 		pcc_mbox_free_channel(ctx->pcc_chan);
730 }
731 
732 static const struct of_device_id xgene_hwmon_of_match[] = {
733 	{.compatible = "apm,xgene-slimpro-hwmon"},
734 	{}
735 };
736 MODULE_DEVICE_TABLE(of, xgene_hwmon_of_match);
737 
738 static struct platform_driver xgene_hwmon_driver = {
739 	.probe = xgene_hwmon_probe,
740 	.remove = xgene_hwmon_remove,
741 	.driver = {
742 		.name = "xgene-slimpro-hwmon",
743 		.of_match_table = xgene_hwmon_of_match,
744 		.acpi_match_table = ACPI_PTR(xgene_hwmon_acpi_match),
745 	},
746 };
747 module_platform_driver(xgene_hwmon_driver);
748 
749 MODULE_DESCRIPTION("APM X-Gene SoC hardware monitor");
750 MODULE_LICENSE("GPL");
751