xref: /openbmc/linux/drivers/fsi/fsi-occ.c (revision 287dcc2b)
1 // SPDX-License-Identifier: GPL-2.0
2 
3 #include <linux/device.h>
4 #include <linux/err.h>
5 #include <linux/errno.h>
6 #include <linux/fs.h>
7 #include <linux/fsi-sbefifo.h>
8 #include <linux/gfp.h>
9 #include <linux/idr.h>
10 #include <linux/kernel.h>
11 #include <linux/list.h>
12 #include <linux/miscdevice.h>
13 #include <linux/mm.h>
14 #include <linux/module.h>
15 #include <linux/mutex.h>
16 #include <linux/fsi-occ.h>
17 #include <linux/of.h>
18 #include <linux/of_device.h>
19 #include <linux/platform_device.h>
20 #include <linux/sched.h>
21 #include <linux/slab.h>
22 #include <linux/uaccess.h>
23 #include <asm/unaligned.h>
24 
25 #define OCC_SRAM_BYTES		4096
26 #define OCC_CMD_DATA_BYTES	4090
27 #define OCC_RESP_DATA_BYTES	4089
28 
29 #define OCC_P9_SRAM_CMD_ADDR	0xFFFBE000
30 #define OCC_P9_SRAM_RSP_ADDR	0xFFFBF000
31 
32 #define OCC_P10_SRAM_CMD_ADDR	0xFFFFD000
33 #define OCC_P10_SRAM_RSP_ADDR	0xFFFFE000
34 
35 #define OCC_P10_SRAM_MODE	0x58	/* Normal mode, OCB channel 2 */
36 
37 #define OCC_TIMEOUT_MS		1000
38 #define OCC_CMD_IN_PRG_WAIT_MS	50
39 
40 enum versions { occ_p9, occ_p10 };
41 
42 struct occ {
43 	struct device *dev;
44 	struct device *sbefifo;
45 	char name[32];
46 	int idx;
47 	bool platform_hwmon;
48 	u8 sequence_number;
49 	void *buffer;
50 	void *client_buffer;
51 	size_t client_buffer_size;
52 	size_t client_response_size;
53 	enum versions version;
54 	struct miscdevice mdev;
55 	struct mutex occ_lock;
56 };
57 
58 #define to_occ(x)	container_of((x), struct occ, mdev)
59 
60 struct occ_response {
61 	u8 seq_no;
62 	u8 cmd_type;
63 	u8 return_status;
64 	__be16 data_length;
65 	u8 data[OCC_RESP_DATA_BYTES + 2];	/* two bytes checksum */
66 } __packed;
67 
68 struct occ_client {
69 	struct occ *occ;
70 	struct mutex lock;
71 	size_t data_size;
72 	size_t read_offset;
73 	u8 *buffer;
74 };
75 
76 #define to_client(x)	container_of((x), struct occ_client, xfr)
77 
78 static DEFINE_IDA(occ_ida);
79 
80 static int occ_open(struct inode *inode, struct file *file)
81 {
82 	struct occ_client *client = kzalloc(sizeof(*client), GFP_KERNEL);
83 	struct miscdevice *mdev = file->private_data;
84 	struct occ *occ = to_occ(mdev);
85 
86 	if (!client)
87 		return -ENOMEM;
88 
89 	client->buffer = (u8 *)__get_free_page(GFP_KERNEL);
90 	if (!client->buffer) {
91 		kfree(client);
92 		return -ENOMEM;
93 	}
94 
95 	client->occ = occ;
96 	mutex_init(&client->lock);
97 	file->private_data = client;
98 	get_device(occ->dev);
99 
100 	/* We allocate a 1-page buffer, make sure it all fits */
101 	BUILD_BUG_ON((OCC_CMD_DATA_BYTES + 3) > PAGE_SIZE);
102 	BUILD_BUG_ON((OCC_RESP_DATA_BYTES + 7) > PAGE_SIZE);
103 
104 	return 0;
105 }
106 
107 static ssize_t occ_read(struct file *file, char __user *buf, size_t len,
108 			loff_t *offset)
109 {
110 	struct occ_client *client = file->private_data;
111 	ssize_t rc = 0;
112 
113 	if (!client)
114 		return -ENODEV;
115 
116 	if (len > OCC_SRAM_BYTES)
117 		return -EINVAL;
118 
119 	mutex_lock(&client->lock);
120 
121 	/* This should not be possible ... */
122 	if (WARN_ON_ONCE(client->read_offset > client->data_size)) {
123 		rc = -EIO;
124 		goto done;
125 	}
126 
127 	/* Grab how much data we have to read */
128 	rc = min(len, client->data_size - client->read_offset);
129 	if (copy_to_user(buf, client->buffer + client->read_offset, rc))
130 		rc = -EFAULT;
131 	else
132 		client->read_offset += rc;
133 
134  done:
135 	mutex_unlock(&client->lock);
136 
137 	return rc;
138 }
139 
140 static ssize_t occ_write(struct file *file, const char __user *buf,
141 			 size_t len, loff_t *offset)
142 {
143 	struct occ_client *client = file->private_data;
144 	size_t rlen, data_length;
145 	ssize_t rc;
146 	u8 *cmd;
147 
148 	if (!client)
149 		return -ENODEV;
150 
151 	if (len > (OCC_CMD_DATA_BYTES + 3) || len < 3)
152 		return -EINVAL;
153 
154 	mutex_lock(&client->lock);
155 
156 	/* Construct the command */
157 	cmd = client->buffer;
158 
159 	/*
160 	 * Copy the user command (assume user data follows the occ command
161 	 * format)
162 	 * byte 0: command type
163 	 * bytes 1-2: data length (msb first)
164 	 * bytes 3-n: data
165 	 */
166 	if (copy_from_user(&cmd[1], buf, len)) {
167 		rc = -EFAULT;
168 		goto done;
169 	}
170 
171 	/* Extract data length */
172 	data_length = (cmd[2] << 8) + cmd[3];
173 	if (data_length > OCC_CMD_DATA_BYTES) {
174 		rc = -EINVAL;
175 		goto done;
176 	}
177 
178 	/* Submit command; 4 bytes before the data and 2 bytes after */
179 	rlen = PAGE_SIZE;
180 	rc = fsi_occ_submit(client->occ->dev, cmd, data_length + 6, cmd,
181 			    &rlen);
182 	if (rc)
183 		goto done;
184 
185 	/* Set read tracking data */
186 	client->data_size = rlen;
187 	client->read_offset = 0;
188 
189 	/* Done */
190 	rc = len;
191 
192  done:
193 	mutex_unlock(&client->lock);
194 
195 	return rc;
196 }
197 
198 static int occ_release(struct inode *inode, struct file *file)
199 {
200 	struct occ_client *client = file->private_data;
201 
202 	put_device(client->occ->dev);
203 	free_page((unsigned long)client->buffer);
204 	kfree(client);
205 
206 	return 0;
207 }
208 
209 static const struct file_operations occ_fops = {
210 	.owner = THIS_MODULE,
211 	.open = occ_open,
212 	.read = occ_read,
213 	.write = occ_write,
214 	.release = occ_release,
215 };
216 
217 static void occ_save_ffdc(struct occ *occ, __be32 *resp, size_t parsed_len,
218 			  size_t resp_len)
219 {
220 	if (resp_len > parsed_len) {
221 		size_t dh = resp_len - parsed_len;
222 		size_t ffdc_len = (dh - 1) * 4; /* SBE words are four bytes */
223 		__be32 *ffdc = &resp[parsed_len];
224 
225 		if (ffdc_len > occ->client_buffer_size)
226 			ffdc_len = occ->client_buffer_size;
227 
228 		memcpy(occ->client_buffer, ffdc, ffdc_len);
229 		occ->client_response_size = ffdc_len;
230 	}
231 }
232 
233 static int occ_verify_checksum(struct occ *occ, struct occ_response *resp,
234 			       u16 data_length)
235 {
236 	/* Fetch the two bytes after the data for the checksum. */
237 	u16 checksum_resp = get_unaligned_be16(&resp->data[data_length]);
238 	u16 checksum;
239 	u16 i;
240 
241 	checksum = resp->seq_no;
242 	checksum += resp->cmd_type;
243 	checksum += resp->return_status;
244 	checksum += (data_length >> 8) + (data_length & 0xFF);
245 
246 	for (i = 0; i < data_length; ++i)
247 		checksum += resp->data[i];
248 
249 	if (checksum != checksum_resp) {
250 		dev_err(occ->dev, "Bad checksum: %04x!=%04x\n", checksum,
251 			checksum_resp);
252 		return -EBADE;
253 	}
254 
255 	return 0;
256 }
257 
258 static int occ_getsram(struct occ *occ, u32 offset, void *data, ssize_t len)
259 {
260 	u32 data_len = ((len + 7) / 8) * 8;	/* must be multiples of 8 B */
261 	size_t cmd_len, parsed_len, resp_data_len;
262 	size_t resp_len = OCC_MAX_RESP_WORDS;
263 	__be32 *resp = occ->buffer;
264 	__be32 cmd[6];
265 	int idx = 0, rc;
266 
267 	/*
268 	 * Magic sequence to do SBE getsram command. SBE will fetch data from
269 	 * specified SRAM address.
270 	 */
271 	switch (occ->version) {
272 	default:
273 	case occ_p9:
274 		cmd_len = 5;
275 		cmd[2] = cpu_to_be32(1);	/* Normal mode */
276 		cmd[3] = cpu_to_be32(OCC_P9_SRAM_RSP_ADDR + offset);
277 		break;
278 	case occ_p10:
279 		idx = 1;
280 		cmd_len = 6;
281 		cmd[2] = cpu_to_be32(OCC_P10_SRAM_MODE);
282 		cmd[3] = 0;
283 		cmd[4] = cpu_to_be32(OCC_P10_SRAM_RSP_ADDR + offset);
284 		break;
285 	}
286 
287 	cmd[0] = cpu_to_be32(cmd_len);
288 	cmd[1] = cpu_to_be32(SBEFIFO_CMD_GET_OCC_SRAM);
289 	cmd[4 + idx] = cpu_to_be32(data_len);
290 
291 	rc = sbefifo_submit(occ->sbefifo, cmd, cmd_len, resp, &resp_len);
292 	if (rc)
293 		return rc;
294 
295 	rc = sbefifo_parse_status(occ->sbefifo, SBEFIFO_CMD_GET_OCC_SRAM,
296 				  resp, resp_len, &parsed_len);
297 	if (rc > 0) {
298 		dev_err(occ->dev, "SRAM read returned failure status: %08x\n",
299 			rc);
300 		occ_save_ffdc(occ, resp, parsed_len, resp_len);
301 		return -ECOMM;
302 	} else if (rc) {
303 		return rc;
304 	}
305 
306 	resp_data_len = be32_to_cpu(resp[parsed_len - 1]);
307 	if (resp_data_len != data_len) {
308 		dev_err(occ->dev, "SRAM read expected %d bytes got %zd\n",
309 			data_len, resp_data_len);
310 		rc = -EBADMSG;
311 	} else {
312 		memcpy(data, resp, len);
313 	}
314 
315 	return rc;
316 }
317 
318 static int occ_putsram(struct occ *occ, const void *data, ssize_t len,
319 		       u8 seq_no, u16 checksum)
320 {
321 	u32 data_len = ((len + 7) / 8) * 8;	/* must be multiples of 8 B */
322 	size_t cmd_len, parsed_len, resp_data_len;
323 	size_t resp_len = OCC_MAX_RESP_WORDS;
324 	__be32 *buf = occ->buffer;
325 	u8 *byte_buf;
326 	int idx = 0, rc;
327 
328 	cmd_len = (occ->version == occ_p10) ? 6 : 5;
329 	cmd_len += data_len >> 2;
330 
331 	/*
332 	 * Magic sequence to do SBE putsram command. SBE will transfer
333 	 * data to specified SRAM address.
334 	 */
335 	buf[0] = cpu_to_be32(cmd_len);
336 	buf[1] = cpu_to_be32(SBEFIFO_CMD_PUT_OCC_SRAM);
337 
338 	switch (occ->version) {
339 	default:
340 	case occ_p9:
341 		buf[2] = cpu_to_be32(1);	/* Normal mode */
342 		buf[3] = cpu_to_be32(OCC_P9_SRAM_CMD_ADDR);
343 		break;
344 	case occ_p10:
345 		idx = 1;
346 		buf[2] = cpu_to_be32(OCC_P10_SRAM_MODE);
347 		buf[3] = 0;
348 		buf[4] = cpu_to_be32(OCC_P10_SRAM_CMD_ADDR);
349 		break;
350 	}
351 
352 	buf[4 + idx] = cpu_to_be32(data_len);
353 	memcpy(&buf[5 + idx], data, len);
354 
355 	byte_buf = (u8 *)&buf[5 + idx];
356 	/*
357 	 * Overwrite the first byte with our sequence number and the last two
358 	 * bytes with the checksum.
359 	 */
360 	byte_buf[0] = seq_no;
361 	byte_buf[len - 2] = checksum >> 8;
362 	byte_buf[len - 1] = checksum & 0xff;
363 
364 	rc = sbefifo_submit(occ->sbefifo, buf, cmd_len, buf, &resp_len);
365 	if (rc)
366 		return rc;
367 
368 	rc = sbefifo_parse_status(occ->sbefifo, SBEFIFO_CMD_PUT_OCC_SRAM,
369 				  buf, resp_len, &parsed_len);
370 	if (rc > 0) {
371 		dev_err(occ->dev, "SRAM write returned failure status: %08x\n",
372 			rc);
373 		occ_save_ffdc(occ, buf, parsed_len, resp_len);
374 		return -ECOMM;
375 	} else if (rc) {
376 		return rc;
377 	}
378 
379 	if (parsed_len != 1) {
380 		dev_err(occ->dev, "SRAM write response length invalid: %zd\n",
381 			parsed_len);
382 		rc = -EBADMSG;
383 	} else {
384 		resp_data_len = be32_to_cpu(buf[0]);
385 		if (resp_data_len != data_len) {
386 			dev_err(occ->dev,
387 				"SRAM write expected %d bytes got %zd\n",
388 				data_len, resp_data_len);
389 			rc = -EBADMSG;
390 		}
391 	}
392 
393 	return rc;
394 }
395 
396 static int occ_trigger_attn(struct occ *occ)
397 {
398 	__be32 *buf = occ->buffer;
399 	size_t cmd_len, parsed_len, resp_data_len;
400 	size_t resp_len = OCC_MAX_RESP_WORDS;
401 	int idx = 0, rc;
402 
403 	switch (occ->version) {
404 	default:
405 	case occ_p9:
406 		cmd_len = 7;
407 		buf[2] = cpu_to_be32(3); /* Circular mode */
408 		buf[3] = 0;
409 		break;
410 	case occ_p10:
411 		idx = 1;
412 		cmd_len = 8;
413 		buf[2] = cpu_to_be32(0xd0); /* Circular mode, OCB Channel 1 */
414 		buf[3] = 0;
415 		buf[4] = 0;
416 		break;
417 	}
418 
419 	buf[0] = cpu_to_be32(cmd_len);		/* Chip-op length in words */
420 	buf[1] = cpu_to_be32(SBEFIFO_CMD_PUT_OCC_SRAM);
421 	buf[4 + idx] = cpu_to_be32(8);		/* Data length in bytes */
422 	buf[5 + idx] = cpu_to_be32(0x20010000);	/* Trigger OCC attention */
423 	buf[6 + idx] = 0;
424 
425 	rc = sbefifo_submit(occ->sbefifo, buf, cmd_len, buf, &resp_len);
426 	if (rc)
427 		return rc;
428 
429 	rc = sbefifo_parse_status(occ->sbefifo, SBEFIFO_CMD_PUT_OCC_SRAM,
430 				  buf, resp_len, &parsed_len);
431 	if (rc > 0) {
432 		dev_err(occ->dev, "SRAM attn returned failure status: %08x\n",
433 			rc);
434 		occ_save_ffdc(occ, buf, parsed_len, resp_len);
435 		return -ECOMM;
436 	} else if (rc) {
437 		return rc;
438 	}
439 
440 	if (parsed_len != 1) {
441 		dev_err(occ->dev, "SRAM attn response length invalid: %zd\n",
442 			parsed_len);
443 		rc = -EBADMSG;
444 	} else {
445 		resp_data_len = be32_to_cpu(buf[0]);
446 		if (resp_data_len != 8) {
447 			dev_err(occ->dev,
448 				"SRAM attn expected 8 bytes got %zd\n",
449 				resp_data_len);
450 			rc = -EBADMSG;
451 		}
452 	}
453 
454 	return rc;
455 }
456 
457 static bool fsi_occ_response_not_ready(struct occ_response *resp, u8 seq_no,
458 				       u8 cmd_type)
459 {
460 	return resp->return_status == OCC_RESP_CMD_IN_PRG ||
461 		resp->return_status == OCC_RESP_CRIT_INIT ||
462 		resp->seq_no != seq_no || resp->cmd_type != cmd_type;
463 }
464 
465 int fsi_occ_submit(struct device *dev, const void *request, size_t req_len,
466 		   void *response, size_t *resp_len)
467 {
468 	const unsigned long timeout = msecs_to_jiffies(OCC_TIMEOUT_MS);
469 	const unsigned long wait_time =
470 		msecs_to_jiffies(OCC_CMD_IN_PRG_WAIT_MS);
471 	struct occ *occ = dev_get_drvdata(dev);
472 	struct occ_response *resp = response;
473 	size_t user_resp_len = *resp_len;
474 	u8 seq_no;
475 	u8 cmd_type;
476 	u16 checksum = 0;
477 	u16 resp_data_length;
478 	const u8 *byte_request = (const u8 *)request;
479 	unsigned long end;
480 	int rc;
481 	size_t i;
482 
483 	*resp_len = 0;
484 
485 	if (!occ)
486 		return -ENODEV;
487 
488 	if (user_resp_len < 7) {
489 		dev_dbg(dev, "Bad resplen %zd\n", user_resp_len);
490 		return -EINVAL;
491 	}
492 
493 	cmd_type = byte_request[1];
494 
495 	/* Checksum the request, ignoring first byte (sequence number). */
496 	for (i = 1; i < req_len - 2; ++i)
497 		checksum += byte_request[i];
498 
499 	rc = mutex_lock_interruptible(&occ->occ_lock);
500 	if (rc)
501 		return rc;
502 
503 	occ->client_buffer = response;
504 	occ->client_buffer_size = user_resp_len;
505 	occ->client_response_size = 0;
506 
507 	if (!occ->buffer) {
508 		rc = -ENOENT;
509 		goto done;
510 	}
511 
512 	/*
513 	 * Get a sequence number and update the counter. Avoid a sequence
514 	 * number of 0 which would pass the response check below even if the
515 	 * OCC response is uninitialized. Any sequence number the user is
516 	 * trying to send is overwritten since this function is the only common
517 	 * interface to the OCC and therefore the only place we can guarantee
518 	 * unique sequence numbers.
519 	 */
520 	seq_no = occ->sequence_number++;
521 	if (!occ->sequence_number)
522 		occ->sequence_number = 1;
523 	checksum += seq_no;
524 
525 	rc = occ_putsram(occ, request, req_len, seq_no, checksum);
526 	if (rc)
527 		goto done;
528 
529 	rc = occ_trigger_attn(occ);
530 	if (rc)
531 		goto done;
532 
533 	end = jiffies + timeout;
534 	while (true) {
535 		/* Read occ response header */
536 		rc = occ_getsram(occ, 0, resp, 8);
537 		if (rc)
538 			goto done;
539 
540 		if (fsi_occ_response_not_ready(resp, seq_no, cmd_type)) {
541 			if (time_after(jiffies, end)) {
542 				dev_err(occ->dev,
543 					"resp timeout status=%02x seq=%d cmd=%d, our seq=%d cmd=%d\n",
544 					resp->return_status, resp->seq_no,
545 					resp->cmd_type, seq_no, cmd_type);
546 				rc = -ETIMEDOUT;
547 				goto done;
548 			}
549 
550 			set_current_state(TASK_UNINTERRUPTIBLE);
551 			schedule_timeout(wait_time);
552 		} else {
553 			/* Extract size of response data */
554 			resp_data_length =
555 				get_unaligned_be16(&resp->data_length);
556 
557 			/*
558 			 * Message size is data length + 5 bytes header + 2
559 			 * bytes checksum
560 			 */
561 			if ((resp_data_length + 7) > user_resp_len) {
562 				rc = -EMSGSIZE;
563 				goto done;
564 			}
565 
566 			/*
567 			 * Get the entire response including the header again,
568 			 * in case it changed
569 			 */
570 			if (resp_data_length > 1) {
571 				rc = occ_getsram(occ, 0, resp,
572 						 resp_data_length + 7);
573 				if (rc)
574 					goto done;
575 
576 				if (!fsi_occ_response_not_ready(resp, seq_no,
577 								cmd_type))
578 					break;
579 			} else {
580 				break;
581 			}
582 		}
583 	}
584 
585 	dev_dbg(dev, "resp_status=%02x resp_data_len=%d\n",
586 		resp->return_status, resp_data_length);
587 
588 	rc = occ_verify_checksum(occ, resp, resp_data_length);
589 	if (rc)
590 		goto done;
591 
592 	occ->client_response_size = resp_data_length + 7;
593 
594  done:
595 	*resp_len = occ->client_response_size;
596 	mutex_unlock(&occ->occ_lock);
597 
598 	return rc;
599 }
600 EXPORT_SYMBOL_GPL(fsi_occ_submit);
601 
602 static int occ_unregister_platform_child(struct device *dev, void *data)
603 {
604 	struct platform_device *hwmon_dev = to_platform_device(dev);
605 
606 	platform_device_unregister(hwmon_dev);
607 
608 	return 0;
609 }
610 
611 static int occ_unregister_of_child(struct device *dev, void *data)
612 {
613 	struct platform_device *hwmon_dev = to_platform_device(dev);
614 
615 	of_device_unregister(hwmon_dev);
616 	if (dev->of_node)
617 		of_node_clear_flag(dev->of_node, OF_POPULATED);
618 
619 	return 0;
620 }
621 
622 static int occ_probe(struct platform_device *pdev)
623 {
624 	int rc;
625 	u32 reg;
626 	char child_name[32];
627 	struct occ *occ;
628 	struct platform_device *hwmon_dev = NULL;
629 	struct device_node *hwmon_node;
630 	struct device *dev = &pdev->dev;
631 	struct platform_device_info hwmon_dev_info = {
632 		.parent = dev,
633 		.name = "occ-hwmon",
634 	};
635 
636 	occ = devm_kzalloc(dev, sizeof(*occ), GFP_KERNEL);
637 	if (!occ)
638 		return -ENOMEM;
639 
640 	/* SBE words are always four bytes */
641 	occ->buffer = kvmalloc(OCC_MAX_RESP_WORDS * 4, GFP_KERNEL);
642 	if (!occ->buffer)
643 		return -ENOMEM;
644 
645 	occ->version = (uintptr_t)of_device_get_match_data(dev);
646 	occ->dev = dev;
647 	occ->sbefifo = dev->parent;
648 	/*
649 	 * Quickly derive a pseudo-random number from jiffies so that
650 	 * re-probing the driver doesn't accidentally overlap sequence numbers.
651 	 */
652 	occ->sequence_number = (u8)((jiffies % 0xff) + 1);
653 	mutex_init(&occ->occ_lock);
654 
655 	if (dev->of_node) {
656 		rc = of_property_read_u32(dev->of_node, "reg", &reg);
657 		if (!rc) {
658 			/* make sure we don't have a duplicate from dts */
659 			occ->idx = ida_simple_get(&occ_ida, reg, reg + 1,
660 						  GFP_KERNEL);
661 			if (occ->idx < 0)
662 				occ->idx = ida_simple_get(&occ_ida, 1, INT_MAX,
663 							  GFP_KERNEL);
664 		} else {
665 			occ->idx = ida_simple_get(&occ_ida, 1, INT_MAX,
666 						  GFP_KERNEL);
667 		}
668 	} else {
669 		occ->idx = ida_simple_get(&occ_ida, 1, INT_MAX, GFP_KERNEL);
670 	}
671 
672 	platform_set_drvdata(pdev, occ);
673 
674 	snprintf(occ->name, sizeof(occ->name), "occ%d", occ->idx);
675 	occ->mdev.fops = &occ_fops;
676 	occ->mdev.minor = MISC_DYNAMIC_MINOR;
677 	occ->mdev.name = occ->name;
678 	occ->mdev.parent = dev;
679 
680 	rc = misc_register(&occ->mdev);
681 	if (rc) {
682 		dev_err(dev, "failed to register miscdevice: %d\n", rc);
683 		ida_simple_remove(&occ_ida, occ->idx);
684 		kvfree(occ->buffer);
685 		return rc;
686 	}
687 
688 	hwmon_node = of_get_child_by_name(dev->of_node, hwmon_dev_info.name);
689 	if (hwmon_node) {
690 		snprintf(child_name, sizeof(child_name), "%s.%d", hwmon_dev_info.name, occ->idx);
691 		hwmon_dev = of_platform_device_create(hwmon_node, child_name, dev);
692 		of_node_put(hwmon_node);
693 	}
694 
695 	if (!hwmon_dev) {
696 		occ->platform_hwmon = true;
697 		hwmon_dev_info.id = occ->idx;
698 		hwmon_dev = platform_device_register_full(&hwmon_dev_info);
699 		if (IS_ERR(hwmon_dev))
700 			dev_warn(dev, "failed to create hwmon device\n");
701 	}
702 
703 	return 0;
704 }
705 
706 static int occ_remove(struct platform_device *pdev)
707 {
708 	struct occ *occ = platform_get_drvdata(pdev);
709 
710 	misc_deregister(&occ->mdev);
711 
712 	mutex_lock(&occ->occ_lock);
713 	kvfree(occ->buffer);
714 	occ->buffer = NULL;
715 	mutex_unlock(&occ->occ_lock);
716 
717 	if (occ->platform_hwmon)
718 		device_for_each_child(&pdev->dev, NULL, occ_unregister_platform_child);
719 	else
720 		device_for_each_child(&pdev->dev, NULL, occ_unregister_of_child);
721 
722 	ida_simple_remove(&occ_ida, occ->idx);
723 
724 	return 0;
725 }
726 
727 static const struct of_device_id occ_match[] = {
728 	{
729 		.compatible = "ibm,p9-occ",
730 		.data = (void *)occ_p9
731 	},
732 	{
733 		.compatible = "ibm,p10-occ",
734 		.data = (void *)occ_p10
735 	},
736 	{ },
737 };
738 MODULE_DEVICE_TABLE(of, occ_match);
739 
740 static struct platform_driver occ_driver = {
741 	.driver = {
742 		.name = "occ",
743 		.of_match_table	= occ_match,
744 	},
745 	.probe	= occ_probe,
746 	.remove = occ_remove,
747 };
748 
749 static int occ_init(void)
750 {
751 	return platform_driver_register(&occ_driver);
752 }
753 
754 static void occ_exit(void)
755 {
756 	platform_driver_unregister(&occ_driver);
757 
758 	ida_destroy(&occ_ida);
759 }
760 
761 module_init(occ_init);
762 module_exit(occ_exit);
763 
764 MODULE_AUTHOR("Eddie James <eajames@linux.ibm.com>");
765 MODULE_DESCRIPTION("BMC P9 OCC driver");
766 MODULE_LICENSE("GPL");
767