xref: /openbmc/linux/drivers/hwmon/xgene-hwmon.c (revision 81de3bf3)
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 /* PCC defines */
61 #define PCC_SIGNATURE_MASK		0x50424300
62 #define PCCC_GENERATE_DB_INT		BIT(15)
63 #define PCCS_CMD_COMPLETE		BIT(0)
64 #define PCCS_SCI_DOORBEL		BIT(1)
65 #define PCCS_PLATFORM_NOTIFICATION	BIT(3)
66 /*
67  * Arbitrary retries in case the remote processor is slow to respond
68  * to PCC commands
69  */
70 #define PCC_NUM_RETRIES			500
71 
72 #define ASYNC_MSG_FIFO_SIZE		16
73 #define MBOX_OP_TIMEOUTMS		1000
74 
75 #define WATT_TO_mWATT(x)		((x) * 1000)
76 #define mWATT_TO_uWATT(x)		((x) * 1000)
77 #define CELSIUS_TO_mCELSIUS(x)		((x) * 1000)
78 
79 #define to_xgene_hwmon_dev(cl)		\
80 	container_of(cl, struct xgene_hwmon_dev, mbox_client)
81 
82 enum xgene_hwmon_version {
83 	XGENE_HWMON_V1 = 0,
84 	XGENE_HWMON_V2 = 1,
85 };
86 
87 struct slimpro_resp_msg {
88 	u32 msg;
89 	u32 param1;
90 	u32 param2;
91 } __packed;
92 
93 struct xgene_hwmon_dev {
94 	struct device		*dev;
95 	struct mbox_chan	*mbox_chan;
96 	struct mbox_client	mbox_client;
97 	int			mbox_idx;
98 
99 	spinlock_t		kfifo_lock;
100 	struct mutex		rd_mutex;
101 	struct completion	rd_complete;
102 	int			resp_pending;
103 	struct slimpro_resp_msg sync_msg;
104 
105 	struct work_struct	workq;
106 	struct kfifo_rec_ptr_1	async_msg_fifo;
107 
108 	struct device		*hwmon_dev;
109 	bool			temp_critical_alarm;
110 
111 	phys_addr_t		comm_base_addr;
112 	void			*pcc_comm_addr;
113 	u64			usecs_lat;
114 };
115 
116 /*
117  * This function tests and clears a bitmask then returns its old value
118  */
119 static u16 xgene_word_tst_and_clr(u16 *addr, u16 mask)
120 {
121 	u16 ret, val;
122 
123 	val = le16_to_cpu(READ_ONCE(*addr));
124 	ret = val & mask;
125 	val &= ~mask;
126 	WRITE_ONCE(*addr, cpu_to_le16(val));
127 
128 	return ret;
129 }
130 
131 static int xgene_hwmon_pcc_rd(struct xgene_hwmon_dev *ctx, u32 *msg)
132 {
133 	struct acpi_pcct_shared_memory *generic_comm_base = ctx->pcc_comm_addr;
134 	u32 *ptr = (void *)(generic_comm_base + 1);
135 	int rc, i;
136 	u16 val;
137 
138 	mutex_lock(&ctx->rd_mutex);
139 	init_completion(&ctx->rd_complete);
140 	ctx->resp_pending = true;
141 
142 	/* Write signature for subspace */
143 	WRITE_ONCE(generic_comm_base->signature,
144 		   cpu_to_le32(PCC_SIGNATURE_MASK | ctx->mbox_idx));
145 
146 	/* Write to the shared command region */
147 	WRITE_ONCE(generic_comm_base->command,
148 		   cpu_to_le16(MSG_TYPE(msg[0]) | PCCC_GENERATE_DB_INT));
149 
150 	/* Flip CMD COMPLETE bit */
151 	val = le16_to_cpu(READ_ONCE(generic_comm_base->status));
152 	val &= ~PCCS_CMD_COMPLETE;
153 	WRITE_ONCE(generic_comm_base->status, cpu_to_le16(val));
154 
155 	/* Copy the message to the PCC comm space */
156 	for (i = 0; i < sizeof(struct slimpro_resp_msg) / 4; i++)
157 		WRITE_ONCE(ptr[i], cpu_to_le32(msg[i]));
158 
159 	/* Ring the doorbell */
160 	rc = mbox_send_message(ctx->mbox_chan, msg);
161 	if (rc < 0) {
162 		dev_err(ctx->dev, "Mailbox send error %d\n", rc);
163 		goto err;
164 	}
165 	if (!wait_for_completion_timeout(&ctx->rd_complete,
166 					 usecs_to_jiffies(ctx->usecs_lat))) {
167 		dev_err(ctx->dev, "Mailbox operation timed out\n");
168 		rc = -ETIMEDOUT;
169 		goto err;
170 	}
171 
172 	/* Check for error message */
173 	if (MSG_TYPE(ctx->sync_msg.msg) == MSG_TYPE_ERR) {
174 		rc = -EINVAL;
175 		goto err;
176 	}
177 
178 	msg[0] = ctx->sync_msg.msg;
179 	msg[1] = ctx->sync_msg.param1;
180 	msg[2] = ctx->sync_msg.param2;
181 
182 err:
183 	mbox_chan_txdone(ctx->mbox_chan, 0);
184 	ctx->resp_pending = false;
185 	mutex_unlock(&ctx->rd_mutex);
186 	return rc;
187 }
188 
189 static int xgene_hwmon_rd(struct xgene_hwmon_dev *ctx, u32 *msg)
190 {
191 	int rc;
192 
193 	mutex_lock(&ctx->rd_mutex);
194 	init_completion(&ctx->rd_complete);
195 	ctx->resp_pending = true;
196 
197 	rc = mbox_send_message(ctx->mbox_chan, msg);
198 	if (rc < 0) {
199 		dev_err(ctx->dev, "Mailbox send error %d\n", rc);
200 		goto err;
201 	}
202 
203 	if (!wait_for_completion_timeout(&ctx->rd_complete,
204 					 msecs_to_jiffies(MBOX_OP_TIMEOUTMS))) {
205 		dev_err(ctx->dev, "Mailbox operation timed out\n");
206 		rc = -ETIMEDOUT;
207 		goto err;
208 	}
209 
210 	/* Check for error message */
211 	if (MSG_TYPE(ctx->sync_msg.msg) == MSG_TYPE_ERR) {
212 		rc = -EINVAL;
213 		goto err;
214 	}
215 
216 	msg[0] = ctx->sync_msg.msg;
217 	msg[1] = ctx->sync_msg.param1;
218 	msg[2] = ctx->sync_msg.param2;
219 
220 err:
221 	ctx->resp_pending = false;
222 	mutex_unlock(&ctx->rd_mutex);
223 	return rc;
224 }
225 
226 static int xgene_hwmon_reg_map_rd(struct xgene_hwmon_dev *ctx, u32 addr,
227 				  u32 *data)
228 {
229 	u32 msg[3];
230 	int rc;
231 
232 	msg[0] = SENSOR_RD_MSG;
233 	msg[1] = SENSOR_RD_EN_ADDR(addr);
234 	msg[2] = 0;
235 
236 	if (acpi_disabled)
237 		rc = xgene_hwmon_rd(ctx, msg);
238 	else
239 		rc = xgene_hwmon_pcc_rd(ctx, msg);
240 
241 	if (rc < 0)
242 		return rc;
243 
244 	/*
245 	 * Check if sensor data is valid.
246 	 */
247 	if (msg[1] & SENSOR_INVALID_DATA)
248 		return -ENODATA;
249 
250 	*data = msg[1];
251 
252 	return rc;
253 }
254 
255 static int xgene_hwmon_get_notification_msg(struct xgene_hwmon_dev *ctx,
256 					    u32 *amsg)
257 {
258 	u32 msg[3];
259 	int rc;
260 
261 	msg[0] = TPC_EN_MSG(PWRMGMT_SUBTYPE_TPC, TPC_GET_ALARM, 0);
262 	msg[1] = 0;
263 	msg[2] = 0;
264 
265 	rc = xgene_hwmon_pcc_rd(ctx, msg);
266 	if (rc < 0)
267 		return rc;
268 
269 	amsg[0] = msg[0];
270 	amsg[1] = msg[1];
271 	amsg[2] = msg[2];
272 
273 	return rc;
274 }
275 
276 static int xgene_hwmon_get_cpu_pwr(struct xgene_hwmon_dev *ctx, u32 *val)
277 {
278 	u32 watt, mwatt;
279 	int rc;
280 
281 	rc = xgene_hwmon_reg_map_rd(ctx, PMD_PWR_REG, &watt);
282 	if (rc < 0)
283 		return rc;
284 
285 	rc = xgene_hwmon_reg_map_rd(ctx, PMD_PWR_MW_REG, &mwatt);
286 	if (rc < 0)
287 		return rc;
288 
289 	*val = WATT_TO_mWATT(watt) + mwatt;
290 	return 0;
291 }
292 
293 static int xgene_hwmon_get_io_pwr(struct xgene_hwmon_dev *ctx, u32 *val)
294 {
295 	u32 watt, mwatt;
296 	int rc;
297 
298 	rc = xgene_hwmon_reg_map_rd(ctx, SOC_PWR_REG, &watt);
299 	if (rc < 0)
300 		return rc;
301 
302 	rc = xgene_hwmon_reg_map_rd(ctx, SOC_PWR_MW_REG, &mwatt);
303 	if (rc < 0)
304 		return rc;
305 
306 	*val = WATT_TO_mWATT(watt) + mwatt;
307 	return 0;
308 }
309 
310 static int xgene_hwmon_get_temp(struct xgene_hwmon_dev *ctx, u32 *val)
311 {
312 	return xgene_hwmon_reg_map_rd(ctx, SOC_TEMP_REG, val);
313 }
314 
315 /*
316  * Sensor temperature/power functions
317  */
318 static ssize_t temp1_input_show(struct device *dev,
319 				struct device_attribute *attr,
320 				char *buf)
321 {
322 	struct xgene_hwmon_dev *ctx = dev_get_drvdata(dev);
323 	int rc, temp;
324 	u32 val;
325 
326 	rc = xgene_hwmon_get_temp(ctx, &val);
327 	if (rc < 0)
328 		return rc;
329 
330 	temp = sign_extend32(val, TEMP_NEGATIVE_BIT);
331 
332 	return snprintf(buf, PAGE_SIZE, "%d\n", CELSIUS_TO_mCELSIUS(temp));
333 }
334 
335 static ssize_t temp1_label_show(struct device *dev,
336 				struct device_attribute *attr,
337 				char *buf)
338 {
339 	return snprintf(buf, PAGE_SIZE, "SoC Temperature\n");
340 }
341 
342 static ssize_t temp1_critical_alarm_show(struct device *dev,
343 					 struct device_attribute *devattr,
344 					 char *buf)
345 {
346 	struct xgene_hwmon_dev *ctx = dev_get_drvdata(dev);
347 
348 	return snprintf(buf, PAGE_SIZE, "%d\n", ctx->temp_critical_alarm);
349 }
350 
351 static ssize_t power1_label_show(struct device *dev,
352 				 struct device_attribute *attr,
353 				 char *buf)
354 {
355 	return snprintf(buf, PAGE_SIZE, "CPU power\n");
356 }
357 
358 static ssize_t power2_label_show(struct device *dev,
359 				 struct device_attribute *attr,
360 				 char *buf)
361 {
362 	return snprintf(buf, PAGE_SIZE, "IO power\n");
363 }
364 
365 static ssize_t power1_input_show(struct device *dev,
366 				 struct device_attribute *attr,
367 				 char *buf)
368 {
369 	struct xgene_hwmon_dev *ctx = dev_get_drvdata(dev);
370 	u32 val;
371 	int rc;
372 
373 	rc = xgene_hwmon_get_cpu_pwr(ctx, &val);
374 	if (rc < 0)
375 		return rc;
376 
377 	return snprintf(buf, PAGE_SIZE, "%u\n", mWATT_TO_uWATT(val));
378 }
379 
380 static ssize_t power2_input_show(struct device *dev,
381 				 struct device_attribute *attr,
382 				 char *buf)
383 {
384 	struct xgene_hwmon_dev *ctx = dev_get_drvdata(dev);
385 	u32 val;
386 	int rc;
387 
388 	rc = xgene_hwmon_get_io_pwr(ctx, &val);
389 	if (rc < 0)
390 		return rc;
391 
392 	return snprintf(buf, PAGE_SIZE, "%u\n", mWATT_TO_uWATT(val));
393 }
394 
395 static DEVICE_ATTR_RO(temp1_label);
396 static DEVICE_ATTR_RO(temp1_input);
397 static DEVICE_ATTR_RO(temp1_critical_alarm);
398 static DEVICE_ATTR_RO(power1_label);
399 static DEVICE_ATTR_RO(power1_input);
400 static DEVICE_ATTR_RO(power2_label);
401 static DEVICE_ATTR_RO(power2_input);
402 
403 static struct attribute *xgene_hwmon_attrs[] = {
404 	&dev_attr_temp1_label.attr,
405 	&dev_attr_temp1_input.attr,
406 	&dev_attr_temp1_critical_alarm.attr,
407 	&dev_attr_power1_label.attr,
408 	&dev_attr_power1_input.attr,
409 	&dev_attr_power2_label.attr,
410 	&dev_attr_power2_input.attr,
411 	NULL,
412 };
413 
414 ATTRIBUTE_GROUPS(xgene_hwmon);
415 
416 static int xgene_hwmon_tpc_alarm(struct xgene_hwmon_dev *ctx,
417 				 struct slimpro_resp_msg *amsg)
418 {
419 	ctx->temp_critical_alarm = !!amsg->param2;
420 	sysfs_notify(&ctx->dev->kobj, NULL, "temp1_critical_alarm");
421 
422 	return 0;
423 }
424 
425 static void xgene_hwmon_process_pwrmsg(struct xgene_hwmon_dev *ctx,
426 				       struct slimpro_resp_msg *amsg)
427 {
428 	if ((MSG_SUBTYPE(amsg->msg) == PWRMGMT_SUBTYPE_TPC) &&
429 	    (TPC_CMD(amsg->msg) == TPC_ALARM))
430 		xgene_hwmon_tpc_alarm(ctx, amsg);
431 }
432 
433 /*
434  * This function is called to process async work queue
435  */
436 static void xgene_hwmon_evt_work(struct work_struct *work)
437 {
438 	struct slimpro_resp_msg amsg;
439 	struct xgene_hwmon_dev *ctx;
440 	int ret;
441 
442 	ctx = container_of(work, struct xgene_hwmon_dev, workq);
443 	while (kfifo_out_spinlocked(&ctx->async_msg_fifo, &amsg,
444 				    sizeof(struct slimpro_resp_msg),
445 				    &ctx->kfifo_lock)) {
446 		/*
447 		 * If PCC, send a consumer command to Platform to get info
448 		 * If Slimpro Mailbox, get message from specific FIFO
449 		 */
450 		if (!acpi_disabled) {
451 			ret = xgene_hwmon_get_notification_msg(ctx,
452 							       (u32 *)&amsg);
453 			if (ret < 0)
454 				continue;
455 		}
456 
457 		if (MSG_TYPE(amsg.msg) == MSG_TYPE_PWRMGMT)
458 			xgene_hwmon_process_pwrmsg(ctx, &amsg);
459 	}
460 }
461 
462 static int xgene_hwmon_rx_ready(struct xgene_hwmon_dev *ctx, void *msg)
463 {
464 	if (IS_ERR_OR_NULL(ctx->hwmon_dev) && !ctx->resp_pending) {
465 		/* Enqueue to the FIFO */
466 		kfifo_in_spinlocked(&ctx->async_msg_fifo, msg,
467 				    sizeof(struct slimpro_resp_msg),
468 				    &ctx->kfifo_lock);
469 		return -ENODEV;
470 	}
471 
472 	return 0;
473 }
474 
475 /*
476  * This function is called when the SLIMpro Mailbox received a message
477  */
478 static void xgene_hwmon_rx_cb(struct mbox_client *cl, void *msg)
479 {
480 	struct xgene_hwmon_dev *ctx = to_xgene_hwmon_dev(cl);
481 
482 	/*
483 	 * While the driver registers with the mailbox framework, an interrupt
484 	 * can be pending before the probe function completes its
485 	 * initialization. If such condition occurs, just queue up the message
486 	 * as the driver is not ready for servicing the callback.
487 	 */
488 	if (xgene_hwmon_rx_ready(ctx, msg) < 0)
489 		return;
490 
491 	/*
492 	 * Response message format:
493 	 * msg[0] is the return code of the operation
494 	 * msg[1] is the first parameter word
495 	 * msg[2] is the second parameter word
496 	 *
497 	 * As message only supports dword size, just assign it.
498 	 */
499 
500 	/* Check for sync query */
501 	if (ctx->resp_pending &&
502 	    ((MSG_TYPE(((u32 *)msg)[0]) == MSG_TYPE_ERR) ||
503 	     (MSG_TYPE(((u32 *)msg)[0]) == MSG_TYPE_DBG &&
504 	      MSG_SUBTYPE(((u32 *)msg)[0]) == DBG_SUBTYPE_SENSOR_READ) ||
505 	     (MSG_TYPE(((u32 *)msg)[0]) == MSG_TYPE_PWRMGMT &&
506 	      MSG_SUBTYPE(((u32 *)msg)[0]) == PWRMGMT_SUBTYPE_TPC &&
507 	      TPC_CMD(((u32 *)msg)[0]) == TPC_ALARM))) {
508 		ctx->sync_msg.msg = ((u32 *)msg)[0];
509 		ctx->sync_msg.param1 = ((u32 *)msg)[1];
510 		ctx->sync_msg.param2 = ((u32 *)msg)[2];
511 
512 		/* Operation waiting for response */
513 		complete(&ctx->rd_complete);
514 
515 		return;
516 	}
517 
518 	/* Enqueue to the FIFO */
519 	kfifo_in_spinlocked(&ctx->async_msg_fifo, msg,
520 			    sizeof(struct slimpro_resp_msg), &ctx->kfifo_lock);
521 	/* Schedule the bottom handler */
522 	schedule_work(&ctx->workq);
523 }
524 
525 /*
526  * This function is called when the PCC Mailbox received a message
527  */
528 static void xgene_hwmon_pcc_rx_cb(struct mbox_client *cl, void *msg)
529 {
530 	struct xgene_hwmon_dev *ctx = to_xgene_hwmon_dev(cl);
531 	struct acpi_pcct_shared_memory *generic_comm_base = ctx->pcc_comm_addr;
532 	struct slimpro_resp_msg amsg;
533 
534 	/*
535 	 * While the driver registers with the mailbox framework, an interrupt
536 	 * can be pending before the probe function completes its
537 	 * initialization. If such condition occurs, just queue up the message
538 	 * as the driver is not ready for servicing the callback.
539 	 */
540 	if (xgene_hwmon_rx_ready(ctx, &amsg) < 0)
541 		return;
542 
543 	msg = generic_comm_base + 1;
544 	/* Check if platform sends interrupt */
545 	if (!xgene_word_tst_and_clr(&generic_comm_base->status,
546 				    PCCS_SCI_DOORBEL))
547 		return;
548 
549 	/*
550 	 * Response message format:
551 	 * msg[0] is the return code of the operation
552 	 * msg[1] is the first parameter word
553 	 * msg[2] is the second parameter word
554 	 *
555 	 * As message only supports dword size, just assign it.
556 	 */
557 
558 	/* Check for sync query */
559 	if (ctx->resp_pending &&
560 	    ((MSG_TYPE(((u32 *)msg)[0]) == MSG_TYPE_ERR) ||
561 	     (MSG_TYPE(((u32 *)msg)[0]) == MSG_TYPE_DBG &&
562 	      MSG_SUBTYPE(((u32 *)msg)[0]) == DBG_SUBTYPE_SENSOR_READ) ||
563 	     (MSG_TYPE(((u32 *)msg)[0]) == MSG_TYPE_PWRMGMT &&
564 	      MSG_SUBTYPE(((u32 *)msg)[0]) == PWRMGMT_SUBTYPE_TPC &&
565 	      TPC_CMD(((u32 *)msg)[0]) == TPC_ALARM))) {
566 		/* Check if platform completes command */
567 		if (xgene_word_tst_and_clr(&generic_comm_base->status,
568 					   PCCS_CMD_COMPLETE)) {
569 			ctx->sync_msg.msg = ((u32 *)msg)[0];
570 			ctx->sync_msg.param1 = ((u32 *)msg)[1];
571 			ctx->sync_msg.param2 = ((u32 *)msg)[2];
572 
573 			/* Operation waiting for response */
574 			complete(&ctx->rd_complete);
575 
576 			return;
577 		}
578 	}
579 
580 	/*
581 	 * Platform notifies interrupt to OSPM.
582 	 * OPSM schedules a consumer command to get this information
583 	 * in a workqueue. Platform must wait until OSPM has issued
584 	 * a consumer command that serves this notification.
585 	 */
586 
587 	/* Enqueue to the FIFO */
588 	kfifo_in_spinlocked(&ctx->async_msg_fifo, &amsg,
589 			    sizeof(struct slimpro_resp_msg), &ctx->kfifo_lock);
590 	/* Schedule the bottom handler */
591 	schedule_work(&ctx->workq);
592 }
593 
594 static void xgene_hwmon_tx_done(struct mbox_client *cl, void *msg, int ret)
595 {
596 	if (ret) {
597 		dev_dbg(cl->dev, "TX did not complete: CMD sent:%x, ret:%d\n",
598 			*(u16 *)msg, ret);
599 	} else {
600 		dev_dbg(cl->dev, "TX completed. CMD sent:%x, ret:%d\n",
601 			*(u16 *)msg, ret);
602 	}
603 }
604 
605 #ifdef CONFIG_ACPI
606 static const struct acpi_device_id xgene_hwmon_acpi_match[] = {
607 	{"APMC0D29", XGENE_HWMON_V1},
608 	{"APMC0D8A", XGENE_HWMON_V2},
609 	{},
610 };
611 MODULE_DEVICE_TABLE(acpi, xgene_hwmon_acpi_match);
612 #endif
613 
614 static int xgene_hwmon_probe(struct platform_device *pdev)
615 {
616 	struct xgene_hwmon_dev *ctx;
617 	struct mbox_client *cl;
618 	int rc;
619 
620 	ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
621 	if (!ctx)
622 		return -ENOMEM;
623 
624 	ctx->dev = &pdev->dev;
625 	platform_set_drvdata(pdev, ctx);
626 	cl = &ctx->mbox_client;
627 
628 	spin_lock_init(&ctx->kfifo_lock);
629 	mutex_init(&ctx->rd_mutex);
630 
631 	rc = kfifo_alloc(&ctx->async_msg_fifo,
632 			 sizeof(struct slimpro_resp_msg) * ASYNC_MSG_FIFO_SIZE,
633 			 GFP_KERNEL);
634 	if (rc)
635 		return -ENOMEM;
636 
637 	INIT_WORK(&ctx->workq, xgene_hwmon_evt_work);
638 
639 	/* Request mailbox channel */
640 	cl->dev = &pdev->dev;
641 	cl->tx_done = xgene_hwmon_tx_done;
642 	cl->tx_block = false;
643 	cl->tx_tout = MBOX_OP_TIMEOUTMS;
644 	cl->knows_txdone = false;
645 	if (acpi_disabled) {
646 		cl->rx_callback = xgene_hwmon_rx_cb;
647 		ctx->mbox_chan = mbox_request_channel(cl, 0);
648 		if (IS_ERR(ctx->mbox_chan)) {
649 			dev_err(&pdev->dev,
650 				"SLIMpro mailbox channel request failed\n");
651 			rc = -ENODEV;
652 			goto out_mbox_free;
653 		}
654 	} else {
655 		struct acpi_pcct_hw_reduced *cppc_ss;
656 		const struct acpi_device_id *acpi_id;
657 		int version;
658 
659 		acpi_id = acpi_match_device(pdev->dev.driver->acpi_match_table,
660 					    &pdev->dev);
661 		if (!acpi_id)
662 			return -EINVAL;
663 
664 		version = (int)acpi_id->driver_data;
665 
666 		if (device_property_read_u32(&pdev->dev, "pcc-channel",
667 					     &ctx->mbox_idx)) {
668 			dev_err(&pdev->dev, "no pcc-channel property\n");
669 			rc = -ENODEV;
670 			goto out_mbox_free;
671 		}
672 
673 		cl->rx_callback = xgene_hwmon_pcc_rx_cb;
674 		ctx->mbox_chan = pcc_mbox_request_channel(cl, ctx->mbox_idx);
675 		if (IS_ERR(ctx->mbox_chan)) {
676 			dev_err(&pdev->dev,
677 				"PPC channel request failed\n");
678 			rc = -ENODEV;
679 			goto out_mbox_free;
680 		}
681 
682 		/*
683 		 * The PCC mailbox controller driver should
684 		 * have parsed the PCCT (global table of all
685 		 * PCC channels) and stored pointers to the
686 		 * subspace communication region in con_priv.
687 		 */
688 		cppc_ss = ctx->mbox_chan->con_priv;
689 		if (!cppc_ss) {
690 			dev_err(&pdev->dev, "PPC subspace not found\n");
691 			rc = -ENODEV;
692 			goto out;
693 		}
694 
695 		if (!ctx->mbox_chan->mbox->txdone_irq) {
696 			dev_err(&pdev->dev, "PCC IRQ not supported\n");
697 			rc = -ENODEV;
698 			goto out;
699 		}
700 
701 		/*
702 		 * This is the shared communication region
703 		 * for the OS and Platform to communicate over.
704 		 */
705 		ctx->comm_base_addr = cppc_ss->base_address;
706 		if (ctx->comm_base_addr) {
707 			if (version == XGENE_HWMON_V2)
708 				ctx->pcc_comm_addr = (void __force *)ioremap(
709 							ctx->comm_base_addr,
710 							cppc_ss->length);
711 			else
712 				ctx->pcc_comm_addr = memremap(
713 							ctx->comm_base_addr,
714 							cppc_ss->length,
715 							MEMREMAP_WB);
716 		} else {
717 			dev_err(&pdev->dev, "Failed to get PCC comm region\n");
718 			rc = -ENODEV;
719 			goto out;
720 		}
721 
722 		if (!ctx->pcc_comm_addr) {
723 			dev_err(&pdev->dev,
724 				"Failed to ioremap PCC comm region\n");
725 			rc = -ENOMEM;
726 			goto out;
727 		}
728 
729 		/*
730 		 * cppc_ss->latency is just a Nominal value. In reality
731 		 * the remote processor could be much slower to reply.
732 		 * So add an arbitrary amount of wait on top of Nominal.
733 		 */
734 		ctx->usecs_lat = PCC_NUM_RETRIES * cppc_ss->latency;
735 	}
736 
737 	ctx->hwmon_dev = hwmon_device_register_with_groups(ctx->dev,
738 							   "apm_xgene",
739 							   ctx,
740 							   xgene_hwmon_groups);
741 	if (IS_ERR(ctx->hwmon_dev)) {
742 		dev_err(&pdev->dev, "Failed to register HW monitor device\n");
743 		rc = PTR_ERR(ctx->hwmon_dev);
744 		goto out;
745 	}
746 
747 	/*
748 	 * Schedule the bottom handler if there is a pending message.
749 	 */
750 	schedule_work(&ctx->workq);
751 
752 	dev_info(&pdev->dev, "APM X-Gene SoC HW monitor driver registered\n");
753 
754 	return 0;
755 
756 out:
757 	if (acpi_disabled)
758 		mbox_free_channel(ctx->mbox_chan);
759 	else
760 		pcc_mbox_free_channel(ctx->mbox_chan);
761 out_mbox_free:
762 	kfifo_free(&ctx->async_msg_fifo);
763 
764 	return rc;
765 }
766 
767 static int xgene_hwmon_remove(struct platform_device *pdev)
768 {
769 	struct xgene_hwmon_dev *ctx = platform_get_drvdata(pdev);
770 
771 	hwmon_device_unregister(ctx->hwmon_dev);
772 	kfifo_free(&ctx->async_msg_fifo);
773 	if (acpi_disabled)
774 		mbox_free_channel(ctx->mbox_chan);
775 	else
776 		pcc_mbox_free_channel(ctx->mbox_chan);
777 
778 	return 0;
779 }
780 
781 static const struct of_device_id xgene_hwmon_of_match[] = {
782 	{.compatible = "apm,xgene-slimpro-hwmon"},
783 	{}
784 };
785 MODULE_DEVICE_TABLE(of, xgene_hwmon_of_match);
786 
787 static struct platform_driver xgene_hwmon_driver __refdata = {
788 	.probe = xgene_hwmon_probe,
789 	.remove = xgene_hwmon_remove,
790 	.driver = {
791 		.name = "xgene-slimpro-hwmon",
792 		.of_match_table = xgene_hwmon_of_match,
793 		.acpi_match_table = ACPI_PTR(xgene_hwmon_acpi_match),
794 	},
795 };
796 module_platform_driver(xgene_hwmon_driver);
797 
798 MODULE_DESCRIPTION("APM X-Gene SoC hardware monitor");
799 MODULE_LICENSE("GPL");
800