summaryrefslogtreecommitdiffstats
path: root/drivers/fsi/fsi-occ.c
blob: 9eeb856c8905e49c74f07e7212a4804a0eaf019a (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
// SPDX-License-Identifier: GPL-2.0

#include <linux/device.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/fsi-sbefifo.h>
#include <linux/gfp.h>
#include <linux/idr.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/fsi-occ.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <asm/unaligned.h>

#define OCC_SRAM_BYTES		4096
#define OCC_CMD_DATA_BYTES	4090
#define OCC_RESP_DATA_BYTES	4089

#define OCC_SRAM_CMD_ADDR	0xFFFBE000
#define OCC_SRAM_RSP_ADDR	0xFFFBF000

/*
 * Assume we don't have much FFDC, if we do we'll overflow and
 * fail the command. This needs to be big enough for simple
 * commands as well.
 */
#define OCC_SBE_STATUS_WORDS	32

#define OCC_TIMEOUT_MS		1000
#define OCC_CMD_IN_PRG_WAIT_MS	50

struct occ {
	struct device *dev;
	struct device *sbefifo;
	char name[32];
	int idx;
	struct miscdevice mdev;
	struct mutex occ_lock;
};

#define to_occ(x)	container_of((x), struct occ, mdev)

struct occ_response {
	u8 seq_no;
	u8 cmd_type;
	u8 return_status;
	__be16 data_length;
	u8 data[OCC_RESP_DATA_BYTES + 2];	/* two bytes checksum */
} __packed;

struct occ_client {
	struct occ *occ;
	struct mutex lock;
	size_t data_size;
	size_t read_offset;
	u8 *buffer;
};

#define to_client(x)	container_of((x), struct occ_client, xfr)

static DEFINE_IDA(occ_ida);

static int occ_open(struct inode *inode, struct file *file)
{
	struct occ_client *client = kzalloc(sizeof(*client), GFP_KERNEL);
	struct miscdevice *mdev = file->private_data;
	struct occ *occ = to_occ(mdev);

	if (!client)
		return -ENOMEM;

	client->buffer = (u8 *)__get_free_page(GFP_KERNEL);
	if (!client->buffer) {
		kfree(client);
		return -ENOMEM;
	}

	client->occ = occ;
	mutex_init(&client->lock);
	file->private_data = client;

	/* We allocate a 1-page buffer, make sure it all fits */
	BUILD_BUG_ON((OCC_CMD_DATA_BYTES + 3) > PAGE_SIZE);
	BUILD_BUG_ON((OCC_RESP_DATA_BYTES + 7) > PAGE_SIZE);

	return 0;
}

static ssize_t occ_read(struct file *file, char __user *buf, size_t len,
			loff_t *offset)
{
	struct occ_client *client = file->private_data;
	ssize_t rc = 0;

	if (!client)
		return -ENODEV;

	if (len > OCC_SRAM_BYTES)
		return -EINVAL;

	mutex_lock(&client->lock);

	/* This should not be possible ... */
	if (WARN_ON_ONCE(client->read_offset > client->data_size)) {
		rc = -EIO;
		goto done;
	}

	/* Grab how much data we have to read */
	rc = min(len, client->data_size - client->read_offset);
	if (copy_to_user(buf, client->buffer + client->read_offset, rc))
		rc = -EFAULT;
	else
		client->read_offset += rc;

 done:
	mutex_unlock(&client->lock);

	return rc;
}

static ssize_t occ_write(struct file *file, const char __user *buf,
			 size_t len, loff_t *offset)
{
	struct occ_client *client = file->private_data;
	size_t rlen, data_length;
	u16 checksum = 0;
	ssize_t rc, i;
	u8 *cmd;

	if (!client)
		return -ENODEV;

	if (len > (OCC_CMD_DATA_BYTES + 3) || len < 3)
		return -EINVAL;

	mutex_lock(&client->lock);

	/* Construct the command */
	cmd = client->buffer;

	/* Sequence number (we could increment and compare with response) */
	cmd[0] = 1;

	/*
	 * Copy the user command (assume user data follows the occ command
	 * format)
	 * byte 0: command type
	 * bytes 1-2: data length (msb first)
	 * bytes 3-n: data
	 */
	if (copy_from_user(&cmd[1], buf, len)) {
		rc = -EFAULT;
		goto done;
	}

	/* Extract data length */
	data_length = (cmd[2] << 8) + cmd[3];
	if (data_length > OCC_CMD_DATA_BYTES) {
		rc = -EINVAL;
		goto done;
	}

	/* Calculate checksum */
	for (i = 0; i < data_length + 4; ++i)
		checksum += cmd[i];

	cmd[data_length + 4] = checksum >> 8;
	cmd[data_length + 5] = checksum & 0xFF;

	/* Submit command */
	rlen = PAGE_SIZE;
	rc = fsi_occ_submit(client->occ->dev, cmd, data_length + 6, cmd,
			    &rlen);
	if (rc)
		goto done;

	/* Set read tracking data */
	client->data_size = rlen;
	client->read_offset = 0;

	/* Done */
	rc = len;

 done:
	mutex_unlock(&client->lock);

	return rc;
}

static int occ_release(struct inode *inode, struct file *file)
{
	struct occ_client *client = file->private_data;

	free_page((unsigned long)client->buffer);
	kfree(client);

	return 0;
}

static const struct file_operations occ_fops = {
	.owner = THIS_MODULE,
	.open = occ_open,
	.read = occ_read,
	.write = occ_write,
	.release = occ_release,
};

static int occ_verify_checksum(struct occ_response *resp, u16 data_length)
{
	/* Fetch the two bytes after the data for the checksum. */
	u16 checksum_resp = get_unaligned_be16(&resp->data[data_length]);
	u16 checksum;
	u16 i;

	checksum = resp->seq_no;
	checksum += resp->cmd_type;
	checksum += resp->return_status;
	checksum += (data_length >> 8) + (data_length & 0xFF);

	for (i = 0; i < data_length; ++i)
		checksum += resp->data[i];

	if (checksum != checksum_resp)
		return -EBADMSG;

	return 0;
}

static int occ_getsram(struct occ *occ, u32 address, void *data, ssize_t len)
{
	u32 data_len = ((len + 7) / 8) * 8;	/* must be multiples of 8 B */
	size_t resp_len, resp_data_len;
	__be32 *resp, cmd[5];
	int rc;

	/*
	 * Magic sequence to do SBE getsram command. SBE will fetch data from
	 * specified SRAM address.
	 */
	cmd[0] = cpu_to_be32(0x5);
	cmd[1] = cpu_to_be32(SBEFIFO_CMD_GET_OCC_SRAM);
	cmd[2] = cpu_to_be32(1);
	cmd[3] = cpu_to_be32(address);
	cmd[4] = cpu_to_be32(data_len);

	resp_len = (data_len >> 2) + OCC_SBE_STATUS_WORDS;
	resp = kzalloc(resp_len << 2, GFP_KERNEL);
	if (!resp)
		return -ENOMEM;

	rc = sbefifo_submit(occ->sbefifo, cmd, 5, resp, &resp_len);
	if (rc)
		goto free;

	rc = sbefifo_parse_status(occ->sbefifo, SBEFIFO_CMD_GET_OCC_SRAM,
				  resp, resp_len, &resp_len);
	if (rc)
		goto free;

	resp_data_len = be32_to_cpu(resp[resp_len - 1]);
	if (resp_data_len != data_len) {
		dev_err(occ->dev, "SRAM read expected %d bytes got %zd\n",
			data_len, resp_data_len);
		rc = -EBADMSG;
	} else {
		memcpy(data, resp, len);
	}

free:
	/* Convert positive SBEI status */
	if (rc > 0) {
		dev_err(occ->dev, "SRAM read returned failure status: %08x\n",
			rc);
		rc = -EBADMSG;
	}

	kfree(resp);
	return rc;
}

static int occ_putsram(struct occ *occ, u32 address, const void *data,
		       ssize_t len)
{
	size_t cmd_len, buf_len, resp_len, resp_data_len;
	u32 data_len = ((len + 7) / 8) * 8;	/* must be multiples of 8 B */
	__be32 *buf;
	int rc;

	/*
	 * We use the same buffer for command and response, make
	 * sure it's big enough
	 */
	resp_len = OCC_SBE_STATUS_WORDS;
	cmd_len = (data_len >> 2) + 5;
	buf_len = max(cmd_len, resp_len);
	buf = kzalloc(buf_len << 2, GFP_KERNEL);
	if (!buf)
		return -ENOMEM;

	/*
	 * Magic sequence to do SBE putsram command. SBE will transfer
	 * data to specified SRAM address.
	 */
	buf[0] = cpu_to_be32(cmd_len);
	buf[1] = cpu_to_be32(SBEFIFO_CMD_PUT_OCC_SRAM);
	buf[2] = cpu_to_be32(1);
	buf[3] = cpu_to_be32(address);
	buf[4] = cpu_to_be32(data_len);

	memcpy(&buf[5], data, len);

	rc = sbefifo_submit(occ->sbefifo, buf, cmd_len, buf, &resp_len);
	if (rc)
		goto free;

	rc = sbefifo_parse_status(occ->sbefifo, SBEFIFO_CMD_PUT_OCC_SRAM,
				  buf, resp_len, &resp_len);
	if (rc)
		goto free;

	if (resp_len != 1) {
		dev_err(occ->dev, "SRAM write response length invalid: %zd\n",
			resp_len);
		rc = -EBADMSG;
	} else {
		resp_data_len = be32_to_cpu(buf[0]);
		if (resp_data_len != data_len) {
			dev_err(occ->dev,
				"SRAM write expected %d bytes got %zd\n",
				data_len, resp_data_len);
			rc = -EBADMSG;
		}
	}

free:
	/* Convert positive SBEI status */
	if (rc > 0) {
		dev_err(occ->dev, "SRAM write returned failure status: %08x\n",
			rc);
		rc = -EBADMSG;
	}

	kfree(buf);
	return rc;
}

static int occ_trigger_attn(struct occ *occ)
{
	__be32 buf[OCC_SBE_STATUS_WORDS];
	size_t resp_len, resp_data_len;
	int rc;

	BUILD_BUG_ON(OCC_SBE_STATUS_WORDS < 7);
	resp_len = OCC_SBE_STATUS_WORDS;

	buf[0] = cpu_to_be32(0x5 + 0x2);        /* Chip-op length in words */
	buf[1] = cpu_to_be32(SBEFIFO_CMD_PUT_OCC_SRAM);
	buf[2] = cpu_to_be32(0x3);              /* Mode: Circular */
	buf[3] = cpu_to_be32(0x0);              /* Address: ignore in mode 3 */
	buf[4] = cpu_to_be32(0x8);              /* Data length in bytes */
	buf[5] = cpu_to_be32(0x20010000);       /* Trigger OCC attention */
	buf[6] = 0;

	rc = sbefifo_submit(occ->sbefifo, buf, 7, buf, &resp_len);
	if (rc)
		goto error;

	rc = sbefifo_parse_status(occ->sbefifo, SBEFIFO_CMD_PUT_OCC_SRAM,
				  buf, resp_len, &resp_len);
	if (rc)
		goto error;

	if (resp_len != 1) {
		dev_err(occ->dev, "SRAM attn response length invalid: %zd\n",
			resp_len);
		rc = -EBADMSG;
	} else {
		resp_data_len = be32_to_cpu(buf[0]);
		if (resp_data_len != 8) {
			dev_err(occ->dev,
				"SRAM attn expected 8 bytes got %zd\n",
				resp_data_len);
			rc = -EBADMSG;
		}
	}

 error:
	/* Convert positive SBEI status */
	if (rc > 0) {
		dev_err(occ->dev, "SRAM attn returned failure status: %08x\n",
			rc);
		rc = -EBADMSG;
	}

	return rc;
}

int fsi_occ_submit(struct device *dev, const void *request, size_t req_len,
		   void *response, size_t *resp_len)
{
	const unsigned long timeout = msecs_to_jiffies(OCC_TIMEOUT_MS);
	const unsigned long wait_time =
		msecs_to_jiffies(OCC_CMD_IN_PRG_WAIT_MS);
	struct occ *occ = dev_get_drvdata(dev);
	struct occ_response *resp = response;
	u8 seq_no;
	u16 resp_data_length;
	unsigned long start;
	int rc;

	if (!occ)
		return -ENODEV;

	if (*resp_len < 7) {
		dev_dbg(dev, "Bad resplen %zd\n", *resp_len);
		return -EINVAL;
	}

	mutex_lock(&occ->occ_lock);

	/* Extract the seq_no from the command (first byte) */
	seq_no = *(const u8 *)request;
	rc = occ_putsram(occ, OCC_SRAM_CMD_ADDR, request, req_len);
	if (rc)
		goto done;

	rc = occ_trigger_attn(occ);
	if (rc)
		goto done;

	/* Read occ response header */
	start = jiffies;
	do {
		rc = occ_getsram(occ, OCC_SRAM_RSP_ADDR, resp, 8);
		if (rc)
			goto done;

		if (resp->return_status == OCC_RESP_CMD_IN_PRG ||
		    resp->seq_no != seq_no) {
			rc = -ETIMEDOUT;

			if (time_after(jiffies, start + timeout)) {
				dev_err(occ->dev, "resp timeout status=%02x "
					"resp seq_no=%d our seq_no=%d\n",
					resp->return_status, resp->seq_no,
					seq_no);
				goto done;
			}

			set_current_state(TASK_UNINTERRUPTIBLE);
			schedule_timeout(wait_time);
		}
	} while (rc);

	/* Extract size of response data */
	resp_data_length = get_unaligned_be16(&resp->data_length);

	/* Message size is data length + 5 bytes header + 2 bytes checksum */
	if ((resp_data_length + 7) > *resp_len) {
		rc = -EMSGSIZE;
		goto done;
	}

	dev_dbg(dev, "resp_status=%02x resp_data_len=%d\n",
		resp->return_status, resp_data_length);

	/* Grab the rest */
	if (resp_data_length > 1) {
		/* already got 3 bytes resp, also need 2 bytes checksum */
		rc = occ_getsram(occ, OCC_SRAM_RSP_ADDR + 8,
				 &resp->data[3], resp_data_length - 1);
		if (rc)
			goto done;
	}

	*resp_len = resp_data_length + 7;
	rc = occ_verify_checksum(resp, resp_data_length);

 done:
	mutex_unlock(&occ->occ_lock);

	return rc;
}
EXPORT_SYMBOL_GPL(fsi_occ_submit);

static int occ_unregister_child(struct device *dev, void *data)
{
	struct platform_device *hwmon_dev = to_platform_device(dev);

	platform_device_unregister(hwmon_dev);

	return 0;
}

static int occ_probe(struct platform_device *pdev)
{
	int rc;
	u32 reg;
	struct occ *occ;
	struct platform_device *hwmon_dev;
	struct device *dev = &pdev->dev;
	struct platform_device_info hwmon_dev_info = {
		.parent = dev,
		.name = "occ-hwmon",
	};

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

	occ->dev = dev;
	occ->sbefifo = dev->parent;
	mutex_init(&occ->occ_lock);

	if (dev->of_node) {
		rc = of_property_read_u32(dev->of_node, "reg", &reg);
		if (!rc) {
			/* make sure we don't have a duplicate from dts */
			occ->idx = ida_simple_get(&occ_ida, reg, reg + 1,
						  GFP_KERNEL);
			if (occ->idx < 0)
				occ->idx = ida_simple_get(&occ_ida, 1, INT_MAX,
							  GFP_KERNEL);
		} else {
			occ->idx = ida_simple_get(&occ_ida, 1, INT_MAX,
						  GFP_KERNEL);
		}
	} else {
		occ->idx = ida_simple_get(&occ_ida, 1, INT_MAX, GFP_KERNEL);
	}

	platform_set_drvdata(pdev, occ);

	snprintf(occ->name, sizeof(occ->name), "occ%d", occ->idx);
	occ->mdev.fops = &occ_fops;
	occ->mdev.minor = MISC_DYNAMIC_MINOR;
	occ->mdev.name = occ->name;
	occ->mdev.parent = dev;

	rc = misc_register(&occ->mdev);
	if (rc) {
		dev_err(dev, "failed to register miscdevice: %d\n", rc);
		ida_simple_remove(&occ_ida, occ->idx);
		return rc;
	}

	hwmon_dev_info.id = occ->idx;
	hwmon_dev = platform_device_register_full(&hwmon_dev_info);
	if (IS_ERR(hwmon_dev))
		dev_warn(dev, "failed to create hwmon device\n");

	return 0;
}

static int occ_remove(struct platform_device *pdev)
{
	struct occ *occ = platform_get_drvdata(pdev);

	misc_deregister(&occ->mdev);

	device_for_each_child(&pdev->dev, NULL, occ_unregister_child);

	ida_simple_remove(&occ_ida, occ->idx);

	return 0;
}

static const struct of_device_id occ_match[] = {
	{ .compatible = "ibm,p9-occ" },
	{ },
};

static struct platform_driver occ_driver = {
	.driver = {
		.name = "occ",
		.of_match_table	= occ_match,
	},
	.probe	= occ_probe,
	.remove = occ_remove,
};

static int occ_init(void)
{
	return platform_driver_register(&occ_driver);
}

static void occ_exit(void)
{
	platform_driver_unregister(&occ_driver);

	ida_destroy(&occ_ida);
}

module_init(occ_init);
module_exit(occ_exit);

MODULE_AUTHOR("Eddie James <eajames@linux.ibm.com>");
MODULE_DESCRIPTION("BMC P9 OCC driver");
MODULE_LICENSE("GPL");