remoteproc_virtio.c revision 92b38f851470f8d8ea7ed638d546f83b5268bc12 
1/*
2 * Remote processor messaging transport (OMAP platform-specific bits)
3 *
4 * Copyright (C) 2011 Texas Instruments, Inc.
5 * Copyright (C) 2011 Google, Inc.
6 *
7 * Ohad Ben-Cohen <ohad@wizery.com>
8 * Brian Swetland <swetland@google.com>
9 *
10 * This software is licensed under the terms of the GNU General Public
11 * License version 2, as published by the Free Software Foundation, and
12 * may be copied, distributed, and modified under those terms.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17 * GNU General Public License for more details.
18 */
19
20#include <linux/export.h>
21#include <linux/remoteproc.h>
22#include <linux/virtio.h>
23#include <linux/virtio_config.h>
24#include <linux/virtio_ids.h>
25#include <linux/virtio_ring.h>
26#include <linux/err.h>
27#include <linux/kref.h>
28#include <linux/slab.h>
29
30#include "remoteproc_internal.h"
31
32/* kick the remote processor, and let it know which virtqueue to poke at */
33static void rproc_virtio_notify(struct virtqueue *vq)
34{
35	struct rproc_vring *rvring = vq->priv;
36	struct rproc *rproc = rvring->rvdev->rproc;
37	int notifyid = rvring->notifyid;
38
39	dev_dbg(&rproc->dev, "kicking vq index: %d\n", notifyid);
40
41	rproc->ops->kick(rproc, notifyid);
42}
43
44/**
45 * rproc_vq_interrupt() - tell remoteproc that a virtqueue is interrupted
46 * @rproc: handle to the remote processor
47 * @notifyid: index of the signalled virtqueue (unique per this @rproc)
48 *
49 * This function should be called by the platform-specific rproc driver,
50 * when the remote processor signals that a specific virtqueue has pending
51 * messages available.
52 *
53 * Returns IRQ_NONE if no message was found in the @notifyid virtqueue,
54 * and otherwise returns IRQ_HANDLED.
55 */
56irqreturn_t rproc_vq_interrupt(struct rproc *rproc, int notifyid)
57{
58	struct rproc_vring *rvring;
59
60	dev_dbg(&rproc->dev, "vq index %d is interrupted\n", notifyid);
61
62	rvring = idr_find(&rproc->notifyids, notifyid);
63	if (!rvring || !rvring->vq)
64		return IRQ_NONE;
65
66	return vring_interrupt(0, rvring->vq);
67}
68EXPORT_SYMBOL(rproc_vq_interrupt);
69
70static struct virtqueue *rp_find_vq(struct virtio_device *vdev,
71				    unsigned id,
72				    void (*callback)(struct virtqueue *vq),
73				    const char *name)
74{
75	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
76	struct rproc *rproc = vdev_to_rproc(vdev);
77	struct device *dev = &rproc->dev;
78	struct rproc_vring *rvring;
79	struct virtqueue *vq;
80	void *addr;
81	int len, size, ret;
82
83	/* we're temporarily limited to two virtqueues per rvdev */
84	if (id >= ARRAY_SIZE(rvdev->vring))
85		return ERR_PTR(-EINVAL);
86
87	if (!name)
88		return NULL;
89
90	ret = rproc_alloc_vring(rvdev, id);
91	if (ret)
92		return ERR_PTR(ret);
93
94	rvring = &rvdev->vring[id];
95	addr = rvring->va;
96	len = rvring->len;
97
98	/* zero vring */
99	size = vring_size(len, rvring->align);
100	memset(addr, 0, size);
101
102	dev_dbg(dev, "vring%d: va %p qsz %d notifyid %d\n",
103					id, addr, len, rvring->notifyid);
104
105	/*
106	 * Create the new vq, and tell virtio we're not interested in
107	 * the 'weak' smp barriers, since we're talking with a real device.
108	 */
109	vq = vring_new_virtqueue(id, len, rvring->align, vdev, false, addr,
110					rproc_virtio_notify, callback, name);
111	if (!vq) {
112		dev_err(dev, "vring_new_virtqueue %s failed\n", name);
113		rproc_free_vring(rvring);
114		return ERR_PTR(-ENOMEM);
115	}
116
117	rvring->vq = vq;
118	vq->priv = rvring;
119
120	return vq;
121}
122
123static void __rproc_virtio_del_vqs(struct virtio_device *vdev)
124{
125	struct virtqueue *vq, *n;
126	struct rproc_vring *rvring;
127
128	list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
129		rvring = vq->priv;
130		rvring->vq = NULL;
131		vring_del_virtqueue(vq);
132		rproc_free_vring(rvring);
133	}
134}
135
136static void rproc_virtio_del_vqs(struct virtio_device *vdev)
137{
138	struct rproc *rproc = vdev_to_rproc(vdev);
139
140	/* power down the remote processor before deleting vqs */
141	rproc_shutdown(rproc);
142
143	__rproc_virtio_del_vqs(vdev);
144}
145
146static int rproc_virtio_find_vqs(struct virtio_device *vdev, unsigned nvqs,
147		       struct virtqueue *vqs[],
148		       vq_callback_t *callbacks[],
149		       const char *names[])
150{
151	struct rproc *rproc = vdev_to_rproc(vdev);
152	int i, ret;
153
154	for (i = 0; i < nvqs; ++i) {
155		vqs[i] = rp_find_vq(vdev, i, callbacks[i], names[i]);
156		if (IS_ERR(vqs[i])) {
157			ret = PTR_ERR(vqs[i]);
158			goto error;
159		}
160	}
161
162	/* now that the vqs are all set, boot the remote processor */
163	ret = rproc_boot(rproc);
164	if (ret) {
165		dev_err(&rproc->dev, "rproc_boot() failed %d\n", ret);
166		goto error;
167	}
168
169	return 0;
170
171error:
172	__rproc_virtio_del_vqs(vdev);
173	return ret;
174}
175
176static u8 rproc_virtio_get_status(struct virtio_device *vdev)
177{
178	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
179	struct fw_rsc_vdev *rsc;
180
181	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
182
183	return rsc->status;
184}
185
186static void rproc_virtio_set_status(struct virtio_device *vdev, u8 status)
187{
188	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
189	struct fw_rsc_vdev *rsc;
190
191	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
192
193	rsc->status = status;
194	dev_dbg(&vdev->dev, "status: %d\n", status);
195}
196
197static void rproc_virtio_reset(struct virtio_device *vdev)
198{
199	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
200	struct fw_rsc_vdev *rsc;
201
202	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
203
204	rsc->status = 0;
205	dev_dbg(&vdev->dev, "reset !\n");
206}
207
208/* provide the vdev features as retrieved from the firmware */
209static u32 rproc_virtio_get_features(struct virtio_device *vdev)
210{
211	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
212	struct fw_rsc_vdev *rsc;
213
214	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
215
216	return rsc->dfeatures;
217}
218
219static void rproc_virtio_finalize_features(struct virtio_device *vdev)
220{
221	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
222	struct fw_rsc_vdev *rsc;
223
224	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
225
226	/* Give virtio_ring a chance to accept features */
227	vring_transport_features(vdev);
228
229	/*
230	 * Remember the finalized features of our vdev, and provide it
231	 * to the remote processor once it is powered on.
232	 */
233	rsc->gfeatures = vdev->features[0];
234}
235
236static void rproc_virtio_get(struct virtio_device *vdev, unsigned offset,
237							void *buf, unsigned len)
238{
239	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
240	struct fw_rsc_vdev *rsc;
241	void *cfg;
242
243	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
244	cfg = &rsc->vring[rsc->num_of_vrings];
245
246	if (offset + len > rsc->config_len || offset + len < len) {
247		dev_err(&vdev->dev, "rproc_virtio_get: access out of bounds\n");
248		return;
249	}
250
251	memcpy(buf, cfg + offset, len);
252}
253
254static void rproc_virtio_set(struct virtio_device *vdev, unsigned offset,
255		      const void *buf, unsigned len)
256{
257	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
258	struct fw_rsc_vdev *rsc;
259	void *cfg;
260
261	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
262	cfg = &rsc->vring[rsc->num_of_vrings];
263
264	if (offset + len > rsc->config_len || offset + len < len) {
265		dev_err(&vdev->dev, "rproc_virtio_set: access out of bounds\n");
266		return;
267	}
268
269	memcpy(cfg + offset, buf, len);
270}
271
272static const struct virtio_config_ops rproc_virtio_config_ops = {
273	.get_features	= rproc_virtio_get_features,
274	.finalize_features = rproc_virtio_finalize_features,
275	.find_vqs	= rproc_virtio_find_vqs,
276	.del_vqs	= rproc_virtio_del_vqs,
277	.reset		= rproc_virtio_reset,
278	.set_status	= rproc_virtio_set_status,
279	.get_status	= rproc_virtio_get_status,
280	.get		= rproc_virtio_get,
281	.set		= rproc_virtio_set,
282};
283
284/*
285 * This function is called whenever vdev is released, and is responsible
286 * to decrement the remote processor's refcount which was taken when vdev was
287 * added.
288 *
289 * Never call this function directly; it will be called by the driver
290 * core when needed.
291 */
292static void rproc_vdev_release(struct device *dev)
293{
294	struct virtio_device *vdev = dev_to_virtio(dev);
295	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
296	struct rproc *rproc = vdev_to_rproc(vdev);
297
298	list_del(&rvdev->node);
299	kfree(rvdev);
300
301	put_device(&rproc->dev);
302}
303
304/**
305 * rproc_add_virtio_dev() - register an rproc-induced virtio device
306 * @rvdev: the remote vdev
307 *
308 * This function registers a virtio device. This vdev's partent is
309 * the rproc device.
310 *
311 * Returns 0 on success or an appropriate error value otherwise.
312 */
313int rproc_add_virtio_dev(struct rproc_vdev *rvdev, int id)
314{
315	struct rproc *rproc = rvdev->rproc;
316	struct device *dev = &rproc->dev;
317	struct virtio_device *vdev = &rvdev->vdev;
318	int ret;
319
320	vdev->id.device	= id,
321	vdev->config = &rproc_virtio_config_ops,
322	vdev->dev.parent = dev;
323	vdev->dev.release = rproc_vdev_release;
324
325	/*
326	 * We're indirectly making a non-temporary copy of the rproc pointer
327	 * here, because drivers probed with this vdev will indirectly
328	 * access the wrapping rproc.
329	 *
330	 * Therefore we must increment the rproc refcount here, and decrement
331	 * it _only_ when the vdev is released.
332	 */
333	get_device(&rproc->dev);
334
335	ret = register_virtio_device(vdev);
336	if (ret) {
337		put_device(&rproc->dev);
338		dev_err(dev, "failed to register vdev: %d\n", ret);
339		goto out;
340	}
341
342	dev_info(dev, "registered %s (type %d)\n", dev_name(&vdev->dev), id);
343
344out:
345	return ret;
346}
347
348/**
349 * rproc_remove_virtio_dev() - remove an rproc-induced virtio device
350 * @rvdev: the remote vdev
351 *
352 * This function unregisters an existing virtio device.
353 */
354void rproc_remove_virtio_dev(struct rproc_vdev *rvdev)
355{
356	unregister_virtio_device(&rvdev->vdev);
357}
358