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 bool 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	return true;
43}
44
45/**
46 * rproc_vq_interrupt() - tell remoteproc that a virtqueue is interrupted
47 * @rproc: handle to the remote processor
48 * @notifyid: index of the signalled virtqueue (unique per this @rproc)
49 *
50 * This function should be called by the platform-specific rproc driver,
51 * when the remote processor signals that a specific virtqueue has pending
52 * messages available.
53 *
54 * Returns IRQ_NONE if no message was found in the @notifyid virtqueue,
55 * and otherwise returns IRQ_HANDLED.
56 */
57irqreturn_t rproc_vq_interrupt(struct rproc *rproc, int notifyid)
58{
59	struct rproc_vring *rvring;
60
61	dev_dbg(&rproc->dev, "vq index %d is interrupted\n", notifyid);
62
63	rvring = idr_find(&rproc->notifyids, notifyid);
64	if (!rvring || !rvring->vq)
65		return IRQ_NONE;
66
67	return vring_interrupt(0, rvring->vq);
68}
69EXPORT_SYMBOL(rproc_vq_interrupt);
70
71static struct virtqueue *rp_find_vq(struct virtio_device *vdev,
72				    unsigned id,
73				    void (*callback)(struct virtqueue *vq),
74				    const char *name)
75{
76	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
77	struct rproc *rproc = vdev_to_rproc(vdev);
78	struct device *dev = &rproc->dev;
79	struct rproc_vring *rvring;
80	struct virtqueue *vq;
81	void *addr;
82	int len, size, ret;
83
84	/* we're temporarily limited to two virtqueues per rvdev */
85	if (id >= ARRAY_SIZE(rvdev->vring))
86		return ERR_PTR(-EINVAL);
87
88	if (!name)
89		return NULL;
90
91	ret = rproc_alloc_vring(rvdev, id);
92	if (ret)
93		return ERR_PTR(ret);
94
95	rvring = &rvdev->vring[id];
96	addr = rvring->va;
97	len = rvring->len;
98
99	/* zero vring */
100	size = vring_size(len, rvring->align);
101	memset(addr, 0, size);
102
103	dev_dbg(dev, "vring%d: va %p qsz %d notifyid %d\n",
104					id, addr, len, rvring->notifyid);
105
106	/*
107	 * Create the new vq, and tell virtio we're not interested in
108	 * the 'weak' smp barriers, since we're talking with a real device.
109	 */
110	vq = vring_new_virtqueue(id, len, rvring->align, vdev, false, addr,
111					rproc_virtio_notify, callback, name);
112	if (!vq) {
113		dev_err(dev, "vring_new_virtqueue %s failed\n", name);
114		rproc_free_vring(rvring);
115		return ERR_PTR(-ENOMEM);
116	}
117
118	rvring->vq = vq;
119	vq->priv = rvring;
120
121	return vq;
122}
123
124static void __rproc_virtio_del_vqs(struct virtio_device *vdev)
125{
126	struct virtqueue *vq, *n;
127	struct rproc_vring *rvring;
128
129	list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
130		rvring = vq->priv;
131		rvring->vq = NULL;
132		vring_del_virtqueue(vq);
133		rproc_free_vring(rvring);
134	}
135}
136
137static void rproc_virtio_del_vqs(struct virtio_device *vdev)
138{
139	struct rproc *rproc = vdev_to_rproc(vdev);
140
141	/* power down the remote processor before deleting vqs */
142	rproc_shutdown(rproc);
143
144	__rproc_virtio_del_vqs(vdev);
145}
146
147static int rproc_virtio_find_vqs(struct virtio_device *vdev, unsigned nvqs,
148		       struct virtqueue *vqs[],
149		       vq_callback_t *callbacks[],
150		       const char *names[])
151{
152	struct rproc *rproc = vdev_to_rproc(vdev);
153	int i, ret;
154
155	for (i = 0; i < nvqs; ++i) {
156		vqs[i] = rp_find_vq(vdev, i, callbacks[i], names[i]);
157		if (IS_ERR(vqs[i])) {
158			ret = PTR_ERR(vqs[i]);
159			goto error;
160		}
161	}
162
163	/* now that the vqs are all set, boot the remote processor */
164	ret = rproc_boot(rproc);
165	if (ret) {
166		dev_err(&rproc->dev, "rproc_boot() failed %d\n", ret);
167		goto error;
168	}
169
170	return 0;
171
172error:
173	__rproc_virtio_del_vqs(vdev);
174	return ret;
175}
176
177static u8 rproc_virtio_get_status(struct virtio_device *vdev)
178{
179	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
180	struct fw_rsc_vdev *rsc;
181
182	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
183
184	return rsc->status;
185}
186
187static void rproc_virtio_set_status(struct virtio_device *vdev, u8 status)
188{
189	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
190	struct fw_rsc_vdev *rsc;
191
192	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
193
194	rsc->status = status;
195	dev_dbg(&vdev->dev, "status: %d\n", status);
196}
197
198static void rproc_virtio_reset(struct virtio_device *vdev)
199{
200	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
201	struct fw_rsc_vdev *rsc;
202
203	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
204
205	rsc->status = 0;
206	dev_dbg(&vdev->dev, "reset !\n");
207}
208
209/* provide the vdev features as retrieved from the firmware */
210static u32 rproc_virtio_get_features(struct virtio_device *vdev)
211{
212	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
213	struct fw_rsc_vdev *rsc;
214
215	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
216
217	return rsc->dfeatures;
218}
219
220static void rproc_virtio_finalize_features(struct virtio_device *vdev)
221{
222	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
223	struct fw_rsc_vdev *rsc;
224
225	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
226
227	/* Give virtio_ring a chance to accept features */
228	vring_transport_features(vdev);
229
230	/*
231	 * Remember the finalized features of our vdev, and provide it
232	 * to the remote processor once it is powered on.
233	 */
234	rsc->gfeatures = vdev->features[0];
235}
236
237static void rproc_virtio_get(struct virtio_device *vdev, unsigned offset,
238							void *buf, unsigned len)
239{
240	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
241	struct fw_rsc_vdev *rsc;
242	void *cfg;
243
244	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
245	cfg = &rsc->vring[rsc->num_of_vrings];
246
247	if (offset + len > rsc->config_len || offset + len < len) {
248		dev_err(&vdev->dev, "rproc_virtio_get: access out of bounds\n");
249		return;
250	}
251
252	memcpy(buf, cfg + offset, len);
253}
254
255static void rproc_virtio_set(struct virtio_device *vdev, unsigned offset,
256		      const void *buf, unsigned len)
257{
258	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
259	struct fw_rsc_vdev *rsc;
260	void *cfg;
261
262	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
263	cfg = &rsc->vring[rsc->num_of_vrings];
264
265	if (offset + len > rsc->config_len || offset + len < len) {
266		dev_err(&vdev->dev, "rproc_virtio_set: access out of bounds\n");
267		return;
268	}
269
270	memcpy(cfg + offset, buf, len);
271}
272
273static const struct virtio_config_ops rproc_virtio_config_ops = {
274	.get_features	= rproc_virtio_get_features,
275	.finalize_features = rproc_virtio_finalize_features,
276	.find_vqs	= rproc_virtio_find_vqs,
277	.del_vqs	= rproc_virtio_del_vqs,
278	.reset		= rproc_virtio_reset,
279	.set_status	= rproc_virtio_set_status,
280	.get_status	= rproc_virtio_get_status,
281	.get		= rproc_virtio_get,
282	.set		= rproc_virtio_set,
283};
284
285/*
286 * This function is called whenever vdev is released, and is responsible
287 * to decrement the remote processor's refcount which was taken when vdev was
288 * added.
289 *
290 * Never call this function directly; it will be called by the driver
291 * core when needed.
292 */
293static void rproc_vdev_release(struct device *dev)
294{
295	struct virtio_device *vdev = dev_to_virtio(dev);
296	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
297	struct rproc *rproc = vdev_to_rproc(vdev);
298
299	list_del(&rvdev->node);
300	kfree(rvdev);
301
302	put_device(&rproc->dev);
303}
304
305/**
306 * rproc_add_virtio_dev() - register an rproc-induced virtio device
307 * @rvdev: the remote vdev
308 *
309 * This function registers a virtio device. This vdev's partent is
310 * the rproc device.
311 *
312 * Returns 0 on success or an appropriate error value otherwise.
313 */
314int rproc_add_virtio_dev(struct rproc_vdev *rvdev, int id)
315{
316	struct rproc *rproc = rvdev->rproc;
317	struct device *dev = &rproc->dev;
318	struct virtio_device *vdev = &rvdev->vdev;
319	int ret;
320
321	vdev->id.device	= id,
322	vdev->config = &rproc_virtio_config_ops,
323	vdev->dev.parent = dev;
324	vdev->dev.release = rproc_vdev_release;
325
326	/*
327	 * We're indirectly making a non-temporary copy of the rproc pointer
328	 * here, because drivers probed with this vdev will indirectly
329	 * access the wrapping rproc.
330	 *
331	 * Therefore we must increment the rproc refcount here, and decrement
332	 * it _only_ when the vdev is released.
333	 */
334	get_device(&rproc->dev);
335
336	ret = register_virtio_device(vdev);
337	if (ret) {
338		put_device(&rproc->dev);
339		dev_err(dev, "failed to register vdev: %d\n", ret);
340		goto out;
341	}
342
343	dev_info(dev, "registered %s (type %d)\n", dev_name(&vdev->dev), id);
344
345out:
346	return ret;
347}
348
349/**
350 * rproc_remove_virtio_dev() - remove an rproc-induced virtio device
351 * @rvdev: the remote vdev
352 *
353 * This function unregisters an existing virtio device.
354 */
355void rproc_remove_virtio_dev(struct rproc_vdev *rvdev)
356{
357	unregister_virtio_device(&rvdev->vdev);
358}
359