summaryrefslogtreecommitdiff
path: root/arch/powerpc/platforms/powernv/opal-prd.c
blob: c18de0a9b1bdbae39603428339b43112741ba60a (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
/*
 * OPAL Runtime Diagnostics interface driver
 * Supported on POWERNV platform
 *
 * Copyright IBM Corporation 2015
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#define pr_fmt(fmt) "opal-prd: " fmt

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/miscdevice.h>
#include <linux/fs.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/poll.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <asm/opal-prd.h>
#include <asm/opal.h>
#include <asm/io.h>
#include <linux/uaccess.h>


/**
 * The msg member must be at the end of the struct, as it's followed by the
 * message data.
 */
struct opal_prd_msg_queue_item {
	struct list_head		list;
	struct opal_prd_msg_header	msg;
};

static struct device_node *prd_node;
static LIST_HEAD(opal_prd_msg_queue);
static DEFINE_SPINLOCK(opal_prd_msg_queue_lock);
static DECLARE_WAIT_QUEUE_HEAD(opal_prd_msg_wait);
static atomic_t prd_usage;

static bool opal_prd_range_is_valid(uint64_t addr, uint64_t size)
{
	struct device_node *parent, *node;
	bool found;

	if (addr + size < addr)
		return false;

	parent = of_find_node_by_path("/reserved-memory");
	if (!parent)
		return false;

	found = false;

	for_each_child_of_node(parent, node) {
		uint64_t range_addr, range_size, range_end;
		const __be32 *addrp;
		const char *label;

		addrp = of_get_address(node, 0, &range_size, NULL);

		range_addr = of_read_number(addrp, 2);
		range_end = range_addr + range_size;

		label = of_get_property(node, "ibm,prd-label", NULL);

		/* PRD ranges need a label */
		if (!label)
			continue;

		if (range_end <= range_addr)
			continue;

		if (addr >= range_addr && addr + size <= range_end) {
			found = true;
			of_node_put(node);
			break;
		}
	}

	of_node_put(parent);
	return found;
}

static int opal_prd_open(struct inode *inode, struct file *file)
{
	/*
	 * Prevent multiple (separate) processes from concurrent interactions
	 * with the FW PRD channel
	 */
	if (atomic_xchg(&prd_usage, 1) == 1)
		return -EBUSY;

	return 0;
}

/*
 * opal_prd_mmap - maps firmware-provided ranges into userspace
 * @file: file structure for the device
 * @vma: VMA to map the registers into
 */

static int opal_prd_mmap(struct file *file, struct vm_area_struct *vma)
{
	size_t addr, size;
	pgprot_t page_prot;
	int rc;

	pr_devel("opal_prd_mmap(0x%016lx, 0x%016lx, 0x%lx, 0x%lx)\n",
			vma->vm_start, vma->vm_end, vma->vm_pgoff,
			vma->vm_flags);

	addr = vma->vm_pgoff << PAGE_SHIFT;
	size = vma->vm_end - vma->vm_start;

	/* ensure we're mapping within one of the allowable ranges */
	if (!opal_prd_range_is_valid(addr, size))
		return -EINVAL;

	page_prot = phys_mem_access_prot(file, vma->vm_pgoff,
					 size, vma->vm_page_prot);

	rc = remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff, size,
				page_prot);

	return rc;
}

static bool opal_msg_queue_empty(void)
{
	unsigned long flags;
	bool ret;

	spin_lock_irqsave(&opal_prd_msg_queue_lock, flags);
	ret = list_empty(&opal_prd_msg_queue);
	spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags);

	return ret;
}

static __poll_t opal_prd_poll(struct file *file,
		struct poll_table_struct *wait)
{
	poll_wait(file, &opal_prd_msg_wait, wait);

	if (!opal_msg_queue_empty())
		return POLLIN | POLLRDNORM;

	return 0;
}

static ssize_t opal_prd_read(struct file *file, char __user *buf,
		size_t count, loff_t *ppos)
{
	struct opal_prd_msg_queue_item *item;
	unsigned long flags;
	ssize_t size, err;
	int rc;

	/* we need at least a header's worth of data */
	if (count < sizeof(item->msg))
		return -EINVAL;

	if (*ppos)
		return -ESPIPE;

	item = NULL;

	for (;;) {

		spin_lock_irqsave(&opal_prd_msg_queue_lock, flags);
		if (!list_empty(&opal_prd_msg_queue)) {
			item = list_first_entry(&opal_prd_msg_queue,
					struct opal_prd_msg_queue_item, list);
			list_del(&item->list);
		}
		spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags);

		if (item)
			break;

		if (file->f_flags & O_NONBLOCK)
			return -EAGAIN;

		rc = wait_event_interruptible(opal_prd_msg_wait,
				!opal_msg_queue_empty());
		if (rc)
			return -EINTR;
	}

	size = be16_to_cpu(item->msg.size);
	if (size > count) {
		err = -EINVAL;
		goto err_requeue;
	}

	rc = copy_to_user(buf, &item->msg, size);
	if (rc) {
		err = -EFAULT;
		goto err_requeue;
	}

	kfree(item);

	return size;

err_requeue:
	/* eep! re-queue at the head of the list */
	spin_lock_irqsave(&opal_prd_msg_queue_lock, flags);
	list_add(&item->list, &opal_prd_msg_queue);
	spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags);
	return err;
}

static ssize_t opal_prd_write(struct file *file, const char __user *buf,
		size_t count, loff_t *ppos)
{
	struct opal_prd_msg_header hdr;
	ssize_t size;
	void *msg;
	int rc;

	size = sizeof(hdr);

	if (count < size)
		return -EINVAL;

	/* grab the header */
	rc = copy_from_user(&hdr, buf, sizeof(hdr));
	if (rc)
		return -EFAULT;

	size = be16_to_cpu(hdr.size);

	msg = memdup_user(buf, size);
	if (IS_ERR(msg))
		return PTR_ERR(msg);

	rc = opal_prd_msg(msg);
	if (rc) {
		pr_warn("write: opal_prd_msg returned %d\n", rc);
		size = -EIO;
	}

	kfree(msg);

	return size;
}

static int opal_prd_release(struct inode *inode, struct file *file)
{
	struct opal_prd_msg_header msg;

	msg.size = cpu_to_be16(sizeof(msg));
	msg.type = OPAL_PRD_MSG_TYPE_FINI;

	opal_prd_msg((struct opal_prd_msg *)&msg);

	atomic_xchg(&prd_usage, 0);

	return 0;
}

static long opal_prd_ioctl(struct file *file, unsigned int cmd,
		unsigned long param)
{
	struct opal_prd_info info;
	struct opal_prd_scom scom;
	int rc = 0;

	switch (cmd) {
	case OPAL_PRD_GET_INFO:
		memset(&info, 0, sizeof(info));
		info.version = OPAL_PRD_KERNEL_VERSION;
		rc = copy_to_user((void __user *)param, &info, sizeof(info));
		if (rc)
			return -EFAULT;
		break;

	case OPAL_PRD_SCOM_READ:
		rc = copy_from_user(&scom, (void __user *)param, sizeof(scom));
		if (rc)
			return -EFAULT;

		scom.rc = opal_xscom_read(scom.chip, scom.addr,
				(__be64 *)&scom.data);
		scom.data = be64_to_cpu(scom.data);
		pr_devel("ioctl SCOM_READ: chip %llx addr %016llx data %016llx rc %lld\n",
				scom.chip, scom.addr, scom.data, scom.rc);

		rc = copy_to_user((void __user *)param, &scom, sizeof(scom));
		if (rc)
			return -EFAULT;
		break;

	case OPAL_PRD_SCOM_WRITE:
		rc = copy_from_user(&scom, (void __user *)param, sizeof(scom));
		if (rc)
			return -EFAULT;

		scom.rc = opal_xscom_write(scom.chip, scom.addr, scom.data);
		pr_devel("ioctl SCOM_WRITE: chip %llx addr %016llx data %016llx rc %lld\n",
				scom.chip, scom.addr, scom.data, scom.rc);

		rc = copy_to_user((void __user *)param, &scom, sizeof(scom));
		if (rc)
			return -EFAULT;
		break;

	default:
		rc = -EINVAL;
	}

	return rc;
}

static const struct file_operations opal_prd_fops = {
	.open		= opal_prd_open,
	.mmap		= opal_prd_mmap,
	.poll		= opal_prd_poll,
	.read		= opal_prd_read,
	.write		= opal_prd_write,
	.unlocked_ioctl	= opal_prd_ioctl,
	.release	= opal_prd_release,
	.owner		= THIS_MODULE,
};

static struct miscdevice opal_prd_dev = {
	.minor		= MISC_DYNAMIC_MINOR,
	.name		= "opal-prd",
	.fops		= &opal_prd_fops,
};

/* opal interface */
static int opal_prd_msg_notifier(struct notifier_block *nb,
		unsigned long msg_type, void *_msg)
{
	struct opal_prd_msg_queue_item *item;
	struct opal_prd_msg_header *hdr;
	struct opal_msg *msg = _msg;
	int msg_size, item_size;
	unsigned long flags;

	if (msg_type != OPAL_MSG_PRD)
		return 0;

	/* Calculate total size of the message and item we need to store. The
	 * 'size' field in the header includes the header itself. */
	hdr = (void *)msg->params;
	msg_size = be16_to_cpu(hdr->size);
	item_size = msg_size + sizeof(*item) - sizeof(item->msg);

	item = kzalloc(item_size, GFP_ATOMIC);
	if (!item)
		return -ENOMEM;

	memcpy(&item->msg, msg->params, msg_size);

	spin_lock_irqsave(&opal_prd_msg_queue_lock, flags);
	list_add_tail(&item->list, &opal_prd_msg_queue);
	spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags);

	wake_up_interruptible(&opal_prd_msg_wait);

	return 0;
}

static struct notifier_block opal_prd_event_nb = {
	.notifier_call	= opal_prd_msg_notifier,
	.next		= NULL,
	.priority	= 0,
};

static int opal_prd_probe(struct platform_device *pdev)
{
	int rc;

	if (!pdev || !pdev->dev.of_node)
		return -ENODEV;

	/* We should only have one prd driver instance per machine; ensure
	 * that we only get a valid probe on a single OF node.
	 */
	if (prd_node)
		return -EBUSY;

	prd_node = pdev->dev.of_node;

	rc = opal_message_notifier_register(OPAL_MSG_PRD, &opal_prd_event_nb);
	if (rc) {
		pr_err("Couldn't register event notifier\n");
		return rc;
	}

	rc = misc_register(&opal_prd_dev);
	if (rc) {
		pr_err("failed to register miscdev\n");
		opal_message_notifier_unregister(OPAL_MSG_PRD,
				&opal_prd_event_nb);
		return rc;
	}

	return 0;
}

static int opal_prd_remove(struct platform_device *pdev)
{
	misc_deregister(&opal_prd_dev);
	opal_message_notifier_unregister(OPAL_MSG_PRD, &opal_prd_event_nb);
	return 0;
}

static const struct of_device_id opal_prd_match[] = {
	{ .compatible = "ibm,opal-prd" },
	{ },
};

static struct platform_driver opal_prd_driver = {
	.driver = {
		.name		= "opal-prd",
		.of_match_table	= opal_prd_match,
	},
	.probe	= opal_prd_probe,
	.remove	= opal_prd_remove,
};

module_platform_driver(opal_prd_driver);

MODULE_DEVICE_TABLE(of, opal_prd_match);
MODULE_DESCRIPTION("PowerNV OPAL runtime diagnostic driver");
MODULE_LICENSE("GPL");