aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/misc/mic/card/mic_virtio.c
blob: 20c567b1760b0e964538fcf7d444dc9980999770 (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
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
/*
 * Intel MIC Platform Software Stack (MPSS)
 *
 * Copyright(c) 2013 Intel Corporation.
 *
 * 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.
 *
 * The full GNU General Public License is included in this distribution in
 * the file called "COPYING".
 *
 * Disclaimer: The codes contained in these modules may be specific to
 * the Intel Software Development Platform codenamed: Knights Ferry, and
 * the Intel product codenamed: Knights Corner, and are not backward
 * compatible with other Intel products. Additionally, Intel will NOT
 * support the codes or instruction set in future products.
 *
 * Adapted from:
 *
 * virtio for kvm on s390
 *
 * Copyright IBM Corp. 2008
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License (version 2 only)
 * as published by the Free Software Foundation.
 *
 *    Author(s): Christian Borntraeger <borntraeger@de.ibm.com>
 *
 * Intel MIC Card driver.
 *
 */
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/virtio_config.h>

#include "../common/mic_dev.h"
#include "mic_virtio.h"

#define VIRTIO_SUBCODE_64 0x0D00

#define MIC_MAX_VRINGS                4
struct mic_vdev {
	struct virtio_device vdev;
	struct mic_device_desc __iomem *desc;
	struct mic_device_ctrl __iomem *dc;
	struct mic_device *mdev;
	void __iomem *vr[MIC_MAX_VRINGS];
	int used_size[MIC_MAX_VRINGS];
	struct completion reset_done;
	struct mic_irq *virtio_cookie;
	int c2h_vdev_db;
};

static struct mic_irq *virtio_config_cookie;
#define to_micvdev(vd) container_of(vd, struct mic_vdev, vdev)

/* Helper API to obtain the parent of the virtio device */
static inline struct device *mic_dev(struct mic_vdev *mvdev)
{
	return mvdev->vdev.dev.parent;
}

/* This gets the device's feature bits. */
static u32 mic_get_features(struct virtio_device *vdev)
{
	unsigned int i, bits;
	u32 features = 0;
	struct mic_device_desc __iomem *desc = to_micvdev(vdev)->desc;
	u8 __iomem *in_features = mic_vq_features(desc);
	int feature_len = ioread8(&desc->feature_len);

	bits = min_t(unsigned, feature_len,
		sizeof(vdev->features)) * 8;
	for (i = 0; i < bits; i++)
		if (ioread8(&in_features[i / 8]) & (BIT(i % 8)))
			features |= BIT(i);

	return features;
}

static void mic_finalize_features(struct virtio_device *vdev)
{
	unsigned int i, bits;
	struct mic_device_desc __iomem *desc = to_micvdev(vdev)->desc;
	u8 feature_len = ioread8(&desc->feature_len);
	/* Second half of bitmap is features we accept. */
	u8 __iomem *out_features =
		mic_vq_features(desc) + feature_len;

	/* Give virtio_ring a chance to accept features. */
	vring_transport_features(vdev);

	memset_io(out_features, 0, feature_len);
	bits = min_t(unsigned, feature_len,
		sizeof(vdev->features)) * 8;
	for (i = 0; i < bits; i++) {
		if (test_bit(i, vdev->features))
			iowrite8(ioread8(&out_features[i / 8]) | (1 << (i % 8)),
				 &out_features[i / 8]);
	}
}

/*
 * Reading and writing elements in config space
 */
static void mic_get(struct virtio_device *vdev, unsigned int offset,
		   void *buf, unsigned len)
{
	struct mic_device_desc __iomem *desc = to_micvdev(vdev)->desc;

	if (offset + len > ioread8(&desc->config_len))
		return;
	memcpy_fromio(buf, mic_vq_configspace(desc) + offset, len);
}

static void mic_set(struct virtio_device *vdev, unsigned int offset,
		   const void *buf, unsigned len)
{
	struct mic_device_desc __iomem *desc = to_micvdev(vdev)->desc;

	if (offset + len > ioread8(&desc->config_len))
		return;
	memcpy_toio(mic_vq_configspace(desc) + offset, buf, len);
}

/*
 * The operations to get and set the status word just access the status
 * field of the device descriptor. set_status also interrupts the host
 * to tell about status changes.
 */
static u8 mic_get_status(struct virtio_device *vdev)
{
	return ioread8(&to_micvdev(vdev)->desc->status);
}

static void mic_set_status(struct virtio_device *vdev, u8 status)
{
	struct mic_vdev *mvdev = to_micvdev(vdev);
	if (!status)
		return;
	iowrite8(status, &mvdev->desc->status);
	mic_send_intr(mvdev->mdev, mvdev->c2h_vdev_db);
}

/* Inform host on a virtio device reset and wait for ack from host */
static void mic_reset_inform_host(struct virtio_device *vdev)
{
	struct mic_vdev *mvdev = to_micvdev(vdev);
	struct mic_device_ctrl __iomem *dc = mvdev->dc;
	int retry;

	iowrite8(0, &dc->host_ack);
	iowrite8(1, &dc->vdev_reset);
	mic_send_intr(mvdev->mdev, mvdev->c2h_vdev_db);

	/* Wait till host completes all card accesses and acks the reset */
	for (retry = 100; retry--;) {
		if (ioread8(&dc->host_ack))
			break;
		msleep(100);
	};

	dev_dbg(mic_dev(mvdev), "%s: retry: %d\n", __func__, retry);

	/* Reset status to 0 in case we timed out */
	iowrite8(0, &mvdev->desc->status);
}

static void mic_reset(struct virtio_device *vdev)
{
	struct mic_vdev *mvdev = to_micvdev(vdev);

	dev_dbg(mic_dev(mvdev), "%s: virtio id %d\n",
		__func__, vdev->id.device);

	mic_reset_inform_host(vdev);
	complete_all(&mvdev->reset_done);
}

/*
 * The virtio_ring code calls this API when it wants to notify the Host.
 */
static bool mic_notify(struct virtqueue *vq)
{
	struct mic_vdev *mvdev = vq->priv;

	mic_send_intr(mvdev->mdev, mvdev->c2h_vdev_db);
	return true;
}

static void mic_del_vq(struct virtqueue *vq, int n)
{
	struct mic_vdev *mvdev = to_micvdev(vq->vdev);
	struct vring *vr = (struct vring *)(vq + 1);

	free_pages((unsigned long) vr->used, get_order(mvdev->used_size[n]));
	vring_del_virtqueue(vq);
	mic_card_unmap(mvdev->mdev, mvdev->vr[n]);
	mvdev->vr[n] = NULL;
}

static void mic_del_vqs(struct virtio_device *vdev)
{
	struct mic_vdev *mvdev = to_micvdev(vdev);
	struct virtqueue *vq, *n;
	int idx = 0;

	dev_dbg(mic_dev(mvdev), "%s\n", __func__);

	list_for_each_entry_safe(vq, n, &vdev->vqs, list)
		mic_del_vq(vq, idx++);
}

/*
 * This routine will assign vring's allocated in host/io memory. Code in
 * virtio_ring.c however continues to access this io memory as if it were local
 * memory without io accessors.
 */
static struct virtqueue *mic_find_vq(struct virtio_device *vdev,
				     unsigned index,
				     void (*callback)(struct virtqueue *vq),
				     const char *name)
{
	struct mic_vdev *mvdev = to_micvdev(vdev);
	struct mic_vqconfig __iomem *vqconfig;
	struct mic_vqconfig config;
	struct virtqueue *vq;
	void __iomem *va;
	struct _mic_vring_info __iomem *info;
	void *used;
	int vr_size, _vr_size, err, magic;
	struct vring *vr;
	u8 type = ioread8(&mvdev->desc->type);

	if (index >= ioread8(&mvdev->desc->num_vq))
		return ERR_PTR(-ENOENT);

	if (!name)
		return ERR_PTR(-ENOENT);

	/* First assign the vring's allocated in host memory */
	vqconfig = mic_vq_config(mvdev->desc) + index;
	memcpy_fromio(&config, vqconfig, sizeof(config));
	_vr_size = vring_size(config.num, MIC_VIRTIO_RING_ALIGN);
	vr_size = PAGE_ALIGN(_vr_size + sizeof(struct _mic_vring_info));
	va = mic_card_map(mvdev->mdev, config.address, vr_size);
	if (!va)
		return ERR_PTR(-ENOMEM);
	mvdev->vr[index] = va;
	memset_io(va, 0x0, _vr_size);
	vq = vring_new_virtqueue(index,
				config.num, MIC_VIRTIO_RING_ALIGN, vdev,
				false,
				va, mic_notify, callback, name);
	if (!vq) {
		err = -ENOMEM;
		goto unmap;
	}
	info = va + _vr_size;
	magic = ioread32(&info->magic);

	if (WARN(magic != MIC_MAGIC + type + index, "magic mismatch")) {
		err = -EIO;
		goto unmap;
	}

	/* Allocate and reassign used ring now */
	mvdev->used_size[index] = PAGE_ALIGN(sizeof(__u16) * 3 +
			sizeof(struct vring_used_elem) * config.num);
	used = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
					get_order(mvdev->used_size[index]));
	if (!used) {
		err = -ENOMEM;
		dev_err(mic_dev(mvdev), "%s %d err %d\n",
			__func__, __LINE__, err);
		goto del_vq;
	}
	iowrite64(virt_to_phys(used), &vqconfig->used_address);

	/*
	 * To reassign the used ring here we are directly accessing
	 * struct vring_virtqueue which is a private data structure
	 * in virtio_ring.c. At the minimum, a BUILD_BUG_ON() in
	 * vring_new_virtqueue() would ensure that
	 *  (&vq->vring == (struct vring *) (&vq->vq + 1));
	 */
	vr = (struct vring *)(vq + 1);
	vr->used = used;

	vq->priv = mvdev;
	return vq;
del_vq:
	vring_del_virtqueue(vq);
unmap:
	mic_card_unmap(mvdev->mdev, mvdev->vr[index]);
	return ERR_PTR(err);
}

static int mic_find_vqs(struct virtio_device *vdev, unsigned nvqs,
			struct virtqueue *vqs[],
			vq_callback_t *callbacks[],
			const char *names[])
{
	struct mic_vdev *mvdev = to_micvdev(vdev);
	struct mic_device_ctrl __iomem *dc = mvdev->dc;
	int i, err, retry;

	/* We must have this many virtqueues. */
	if (nvqs > ioread8(&mvdev->desc->num_vq))
		return -ENOENT;

	for (i = 0; i < nvqs; ++i) {
		dev_dbg(mic_dev(mvdev), "%s: %d: %s\n",
			__func__, i, names[i]);
		vqs[i] = mic_find_vq(vdev, i, callbacks[i], names[i]);
		if (IS_ERR(vqs[i])) {
			err = PTR_ERR(vqs[i]);
			goto error;
		}
	}

	iowrite8(1, &dc->used_address_updated);
	/*
	 * Send an interrupt to the host to inform it that used
	 * rings have been re-assigned.
	 */
	mic_send_intr(mvdev->mdev, mvdev->c2h_vdev_db);
	for (retry = 100; retry--;) {
		if (!ioread8(&dc->used_address_updated))
			break;
		msleep(100);
	};

	dev_dbg(mic_dev(mvdev), "%s: retry: %d\n", __func__, retry);
	if (!retry) {
		err = -ENODEV;
		goto error;
	}

	return 0;
error:
	mic_del_vqs(vdev);
	return err;
}

/*
 * The config ops structure as defined by virtio config
 */
static struct virtio_config_ops mic_vq_config_ops = {
	.get_features = mic_get_features,
	.finalize_features = mic_finalize_features,
	.get = mic_get,
	.set = mic_set,
	.get_status = mic_get_status,
	.set_status = mic_set_status,
	.reset = mic_reset,
	.find_vqs = mic_find_vqs,
	.del_vqs = mic_del_vqs,
};

static irqreturn_t
mic_virtio_intr_handler(int irq, void *data)
{
	struct mic_vdev *mvdev = data;
	struct virtqueue *vq;

	mic_ack_interrupt(mvdev->mdev);
	list_for_each_entry(vq, &mvdev->vdev.vqs, list)
		vring_interrupt(0, vq);

	return IRQ_HANDLED;
}

static void mic_virtio_release_dev(struct device *_d)
{
	/*
	 * No need for a release method similar to virtio PCI.
	 * Provide an empty one to avoid getting a warning from core.
	 */
}

/*
 * adds a new device and register it with virtio
 * appropriate drivers are loaded by the device model
 */
static int mic_add_device(struct mic_device_desc __iomem *d,
	unsigned int offset, struct mic_driver *mdrv)
{
	struct mic_vdev *mvdev;
	int ret;
	int virtio_db;
	u8 type = ioread8(&d->type);

	mvdev = kzalloc(sizeof(*mvdev), GFP_KERNEL);
	if (!mvdev) {
		dev_err(mdrv->dev, "Cannot allocate mic dev %u type %u\n",
			offset, type);
		return -ENOMEM;
	}

	mvdev->mdev = &mdrv->mdev;
	mvdev->vdev.dev.parent = mdrv->dev;
	mvdev->vdev.dev.release = mic_virtio_release_dev;
	mvdev->vdev.id.device = type;
	mvdev->vdev.config = &mic_vq_config_ops;
	mvdev->desc = d;
	mvdev->dc = (void __iomem *)d + mic_aligned_desc_size(d);
	init_completion(&mvdev->reset_done);

	virtio_db = mic_next_card_db();
	mvdev->virtio_cookie = mic_request_card_irq(mic_virtio_intr_handler,
			"virtio intr", mvdev, virtio_db);
	if (IS_ERR(mvdev->virtio_cookie)) {
		ret = PTR_ERR(mvdev->virtio_cookie);
		goto kfree;
	}
	iowrite8((u8)virtio_db, &mvdev->dc->h2c_vdev_db);
	mvdev->c2h_vdev_db = ioread8(&mvdev->dc->c2h_vdev_db);

	ret = register_virtio_device(&mvdev->vdev);
	if (ret) {
		dev_err(mic_dev(mvdev),
			"Failed to register mic device %u type %u\n",
			offset, type);
		goto free_irq;
	}
	iowrite64((u64)mvdev, &mvdev->dc->vdev);
	dev_dbg(mic_dev(mvdev), "%s: registered mic device %u type %u mvdev %p\n",
		__func__, offset, type, mvdev);

	return 0;

free_irq:
	mic_free_card_irq(mvdev->virtio_cookie, mvdev);
kfree:
	kfree(mvdev);
	return ret;
}

/*
 * match for a mic device with a specific desc pointer
 */
static int mic_match_desc(struct device *dev, void *data)
{
	struct virtio_device *vdev = dev_to_virtio(dev);
	struct mic_vdev *mvdev = to_micvdev(vdev);

	return mvdev->desc == (void __iomem *)data;
}

static void mic_handle_config_change(struct mic_device_desc __iomem *d,
	unsigned int offset, struct mic_driver *mdrv)
{
	struct mic_device_ctrl __iomem *dc
		= (void __iomem *)d + mic_aligned_desc_size(d);
	struct mic_vdev *mvdev = (struct mic_vdev *)ioread64(&dc->vdev);
	struct virtio_driver *drv;

	if (ioread8(&dc->config_change) != MIC_VIRTIO_PARAM_CONFIG_CHANGED)
		return;

	dev_dbg(mdrv->dev, "%s %d\n", __func__, __LINE__);
	drv = container_of(mvdev->vdev.dev.driver,
				struct virtio_driver, driver);
	if (drv->config_changed)
		drv->config_changed(&mvdev->vdev);
	iowrite8(1, &dc->guest_ack);
}

/*
 * removes a virtio device if a hot remove event has been
 * requested by the host.
 */
static int mic_remove_device(struct mic_device_desc __iomem *d,
	unsigned int offset, struct mic_driver *mdrv)
{
	struct mic_device_ctrl __iomem *dc
		= (void __iomem *)d + mic_aligned_desc_size(d);
	struct mic_vdev *mvdev = (struct mic_vdev *)ioread64(&dc->vdev);
	u8 status;
	int ret = -1;

	if (ioread8(&dc->config_change) == MIC_VIRTIO_PARAM_DEV_REMOVE) {
		dev_dbg(mdrv->dev,
			"%s %d config_change %d type %d mvdev %p\n",
			__func__, __LINE__,
			ioread8(&dc->config_change), ioread8(&d->type), mvdev);

		status = ioread8(&d->status);
		reinit_completion(&mvdev->reset_done);
		unregister_virtio_device(&mvdev->vdev);
		mic_free_card_irq(mvdev->virtio_cookie, mvdev);
		if (status & VIRTIO_CONFIG_S_DRIVER_OK)
			wait_for_completion(&mvdev->reset_done);
		kfree(mvdev);
		iowrite8(1, &dc->guest_ack);
		dev_dbg(mdrv->dev, "%s %d guest_ack %d\n",
			__func__, __LINE__, ioread8(&dc->guest_ack));
		ret = 0;
	}

	return ret;
}

#define REMOVE_DEVICES true

static void mic_scan_devices(struct mic_driver *mdrv, bool remove)
{
	s8 type;
	unsigned int i;
	struct mic_device_desc __iomem *d;
	struct mic_device_ctrl __iomem *dc;
	struct device *dev;
	int ret;

	for (i = sizeof(struct mic_bootparam); i < MIC_DP_SIZE;
		i += mic_total_desc_size(d)) {
		d = mdrv->dp + i;
		dc = (void __iomem *)d + mic_aligned_desc_size(d);
		/*
		 * This read barrier is paired with the corresponding write
		 * barrier on the host which is inserted before adding or
		 * removing a virtio device descriptor, by updating the type.
		 */
		rmb();
		type = ioread8(&d->type);

		/* end of list */
		if (type == 0)
			break;

		if (type == -1)
			continue;

		/* device already exists */
		dev = device_find_child(mdrv->dev, d, mic_match_desc);
		if (dev) {
			if (remove)
				iowrite8(MIC_VIRTIO_PARAM_DEV_REMOVE,
					 &dc->config_change);
			put_device(dev);
			mic_handle_config_change(d, i, mdrv);
			ret = mic_remove_device(d, i, mdrv);
			if (!ret && !remove)
				iowrite8(-1, &d->type);
			if (remove) {
				iowrite8(0, &dc->config_change);
				iowrite8(0, &dc->guest_ack);
			}
			continue;
		}

		/* new device */
		dev_dbg(mdrv->dev, "%s %d Adding new virtio device %p\n",
			__func__, __LINE__, d);
		if (!remove)
			mic_add_device(d, i, mdrv);
	}
}

/*
 * mic_hotplug_device tries to find changes in the device page.
 */
static void mic_hotplug_devices(struct work_struct *work)
{
	struct mic_driver *mdrv = container_of(work,
		struct mic_driver, hotplug_work);

	mic_scan_devices(mdrv, !REMOVE_DEVICES);
}

/*
 * Interrupt handler for hot plug/config changes etc.
 */
static irqreturn_t
mic_extint_handler(int irq, void *data)
{
	struct mic_driver *mdrv = (struct mic_driver *)data;

	dev_dbg(mdrv->dev, "%s %d hotplug work\n",
		__func__, __LINE__);
	mic_ack_interrupt(&mdrv->mdev);
	schedule_work(&mdrv->hotplug_work);
	return IRQ_HANDLED;
}

/*
 * Init function for virtio
 */
int mic_devices_init(struct mic_driver *mdrv)
{
	int rc;
	struct mic_bootparam __iomem *bootparam;
	int config_db;

	INIT_WORK(&mdrv->hotplug_work, mic_hotplug_devices);
	mic_scan_devices(mdrv, !REMOVE_DEVICES);

	config_db = mic_next_card_db();
	virtio_config_cookie = mic_request_card_irq(mic_extint_handler,
			"virtio_config_intr", mdrv, config_db);
	if (IS_ERR(virtio_config_cookie)) {
		rc = PTR_ERR(virtio_config_cookie);
		goto exit;
	}

	bootparam = mdrv->dp;
	iowrite8(config_db, &bootparam->h2c_config_db);
	return 0;
exit:
	return rc;
}

/*
 * Uninit function for virtio
 */
void mic_devices_uninit(struct mic_driver *mdrv)
{
	struct mic_bootparam __iomem *bootparam = mdrv->dp;
	iowrite8(-1, &bootparam->h2c_config_db);
	mic_free_card_irq(virtio_config_cookie, mdrv);
	flush_work(&mdrv->hotplug_work);
	mic_scan_devices(mdrv, REMOVE_DEVICES);
}

Privacy Policy