summaryrefslogtreecommitdiffstats
path: root/drivers/remoteproc/remoteproc_virtio.c
blob: 3541b4492f644efa200509e09531b3e0a383bbe6 (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
/*
 * Remote processor messaging transport (OMAP platform-specific bits)
 *
 * Copyright (C) 2011 Texas Instruments, Inc.
 * Copyright (C) 2011 Google, Inc.
 *
 * Ohad Ben-Cohen <ohad@wizery.com>
 * Brian Swetland <swetland@google.com>
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * 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.
 */

#include <linux/export.h>
#include <linux/remoteproc.h>
#include <linux/virtio.h>
#include <linux/virtio_config.h>
#include <linux/virtio_ids.h>
#include <linux/virtio_ring.h>
#include <linux/err.h>
#include <linux/kref.h>
#include <linux/slab.h>

#include "remoteproc_internal.h"

/* kick the remote processor, and let it know which virtqueue to poke at */
static void rproc_virtio_notify(struct virtqueue *vq)
{
	struct rproc_vring *rvring = vq->priv;
	struct rproc *rproc = rvring->rvdev->rproc;
	int notifyid = rvring->notifyid;

	dev_dbg(&rproc->dev, "kicking vq index: %d\n", notifyid);

	rproc->ops->kick(rproc, notifyid);
}

/**
 * rproc_vq_interrupt() - tell remoteproc that a virtqueue is interrupted
 * @rproc: handle to the remote processor
 * @notifyid: index of the signalled virtqueue (unique per this @rproc)
 *
 * This function should be called by the platform-specific rproc driver,
 * when the remote processor signals that a specific virtqueue has pending
 * messages available.
 *
 * Returns IRQ_NONE if no message was found in the @notifyid virtqueue,
 * and otherwise returns IRQ_HANDLED.
 */
irqreturn_t rproc_vq_interrupt(struct rproc *rproc, int notifyid)
{
	struct rproc_vring *rvring;

	dev_dbg(&rproc->dev, "vq index %d is interrupted\n", notifyid);

	rvring = idr_find(&rproc->notifyids, notifyid);
	if (!rvring || !rvring->vq)
		return IRQ_NONE;

	return vring_interrupt(0, rvring->vq);
}
EXPORT_SYMBOL(rproc_vq_interrupt);

static struct virtqueue *rp_find_vq(struct virtio_device *vdev,
				    unsigned id,
				    void (*callback)(struct virtqueue *vq),
				    const char *name)
{
	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
	struct rproc *rproc = vdev_to_rproc(vdev);
	struct device *dev = &rproc->dev;
	struct rproc_vring *rvring;
	struct virtqueue *vq;
	void *addr;
	int len, size, ret;

	/* we're temporarily limited to two virtqueues per rvdev */
	if (id >= ARRAY_SIZE(rvdev->vring))
		return ERR_PTR(-EINVAL);

	ret = rproc_alloc_vring(rvdev, id);
	if (ret)
		return ERR_PTR(ret);

	rvring = &rvdev->vring[id];
	addr = rvring->va;
	len = rvring->len;

	/* zero vring */
	size = vring_size(len, rvring->align);
	memset(addr, 0, size);

	dev_dbg(dev, "vring%d: va %p qsz %d notifyid %d\n",
					id, addr, len, rvring->notifyid);

	/*
	 * Create the new vq, and tell virtio we're not interested in
	 * the 'weak' smp barriers, since we're talking with a real device.
	 */
	vq = vring_new_virtqueue(len, rvring->align, vdev, false, addr,
					rproc_virtio_notify, callback, name);
	if (!vq) {
		dev_err(dev, "vring_new_virtqueue %s failed\n", name);
		rproc_free_vring(rvring);
		return ERR_PTR(-ENOMEM);
	}

	rvring->vq = vq;
	vq->priv = rvring;

	return vq;
}

static void rproc_virtio_del_vqs(struct virtio_device *vdev)
{
	struct virtqueue *vq, *n;
	struct rproc *rproc = vdev_to_rproc(vdev);
	struct rproc_vring *rvring;

	/* power down the remote processor before deleting vqs */
	rproc_shutdown(rproc);

	list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
		rvring = vq->priv;
		rvring->vq = NULL;
		vring_del_virtqueue(vq);
		rproc_free_vring(rvring);
	}
}

static int rproc_virtio_find_vqs(struct virtio_device *vdev, unsigned nvqs,
		       struct virtqueue *vqs[],
		       vq_callback_t *callbacks[],
		       const char *names[])
{
	struct rproc *rproc = vdev_to_rproc(vdev);
	int i, ret;

	for (i = 0; i < nvqs; ++i) {
		vqs[i] = rp_find_vq(vdev, i, callbacks[i], names[i]);
		if (IS_ERR(vqs[i])) {
			ret = PTR_ERR(vqs[i]);
			goto error;
		}
	}

	/* now that the vqs are all set, boot the remote processor */
	ret = rproc_boot(rproc);
	if (ret) {
		dev_err(&rproc->dev, "rproc_boot() failed %d\n", ret);
		goto error;
	}

	return 0;

error:
	rproc_virtio_del_vqs(vdev);
	return ret;
}

/*
 * We don't support yet real virtio status semantics.
 *
 * The plan is to provide this via the VDEV resource entry
 * which is part of the firmware: this way the remote processor
 * will be able to access the status values as set by us.
 */
static u8 rproc_virtio_get_status(struct virtio_device *vdev)
{
	return 0;
}

static void rproc_virtio_set_status(struct virtio_device *vdev, u8 status)
{
	dev_dbg(&vdev->dev, "status: %d\n", status);
}

static void rproc_virtio_reset(struct virtio_device *vdev)
{
	dev_dbg(&vdev->dev, "reset !\n");
}

/* provide the vdev features as retrieved from the firmware */
static u32 rproc_virtio_get_features(struct virtio_device *vdev)
{
	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);

	return rvdev->dfeatures;
}

static void rproc_virtio_finalize_features(struct virtio_device *vdev)
{
	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);

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

	/*
	 * Remember the finalized features of our vdev, and provide it
	 * to the remote processor once it is powered on.
	 *
	 * Similarly to the status field, we don't expose yet the negotiated
	 * features to the remote processors at this point. This will be
	 * fixed as part of a small resource table overhaul and then an
	 * extension of the virtio resource entries.
	 */
	rvdev->gfeatures = vdev->features[0];
}

static struct virtio_config_ops rproc_virtio_config_ops = {
	.get_features	= rproc_virtio_get_features,
	.finalize_features = rproc_virtio_finalize_features,
	.find_vqs	= rproc_virtio_find_vqs,
	.del_vqs	= rproc_virtio_del_vqs,
	.reset		= rproc_virtio_reset,
	.set_status	= rproc_virtio_set_status,
	.get_status	= rproc_virtio_get_status,
};

/*
 * This function is called whenever vdev is released, and is responsible
 * to decrement the remote processor's refcount which was taken when vdev was
 * added.
 *
 * Never call this function directly; it will be called by the driver
 * core when needed.
 */
static void rproc_vdev_release(struct device *dev)
{
	struct virtio_device *vdev = dev_to_virtio(dev);
	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
	struct rproc *rproc = vdev_to_rproc(vdev);

	list_del(&rvdev->node);
	kfree(rvdev);

	put_device(&rproc->dev);
}

/**
 * rproc_add_virtio_dev() - register an rproc-induced virtio device
 * @rvdev: the remote vdev
 *
 * This function registers a virtio device. This vdev's partent is
 * the rproc device.
 *
 * Returns 0 on success or an appropriate error value otherwise.
 */
int rproc_add_virtio_dev(struct rproc_vdev *rvdev, int id)
{
	struct rproc *rproc = rvdev->rproc;
	struct device *dev = &rproc->dev;
	struct virtio_device *vdev = &rvdev->vdev;
	int ret;

	vdev->id.device	= id,
	vdev->config = &rproc_virtio_config_ops,
	vdev->dev.parent = dev;
	vdev->dev.release = rproc_vdev_release;

	/*
	 * We're indirectly making a non-temporary copy of the rproc pointer
	 * here, because drivers probed with this vdev will indirectly
	 * access the wrapping rproc.
	 *
	 * Therefore we must increment the rproc refcount here, and decrement
	 * it _only_ when the vdev is released.
	 */
	get_device(&rproc->dev);

	ret = register_virtio_device(vdev);
	if (ret) {
		put_device(&rproc->dev);
		dev_err(dev, "failed to register vdev: %d\n", ret);
		goto out;
	}

	dev_info(dev, "registered %s (type %d)\n", dev_name(&vdev->dev), id);

out:
	return ret;
}

/**
 * rproc_remove_virtio_dev() - remove an rproc-induced virtio device
 * @rvdev: the remote vdev
 *
 * This function unregisters an existing virtio device.
 */
void rproc_remove_virtio_dev(struct rproc_vdev *rvdev)
{
	unregister_virtio_device(&rvdev->vdev);
}