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 */
33 static 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  */
57 irqreturn_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 }
69 EXPORT_SYMBOL(rproc_vq_interrupt);
70 
71 static struct virtqueue *rp_find_vq(struct virtio_device *vdev,
72 				    unsigned int id,
73 				    void (*callback)(struct virtqueue *vq),
74 				    const char *name, bool ctx)
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_mem_entry *mem;
80 	struct rproc_vring *rvring;
81 	struct fw_rsc_vdev *rsc;
82 	struct virtqueue *vq;
83 	void *addr;
84 	int len, size;
85 
86 	/* we're temporarily limited to two virtqueues per rvdev */
87 	if (id >= ARRAY_SIZE(rvdev->vring))
88 		return ERR_PTR(-EINVAL);
89 
90 	if (!name)
91 		return NULL;
92 
93 	/* Search allocated memory region by name */
94 	mem = rproc_find_carveout_by_name(rproc, "vdev%dvring%d", rvdev->index,
95 					  id);
96 	if (!mem || !mem->va)
97 		return ERR_PTR(-ENOMEM);
98 
99 	rvring = &rvdev->vring[id];
100 	addr = mem->va;
101 	len = rvring->len;
102 
103 	/* zero vring */
104 	size = vring_size(len, rvring->align);
105 	memset(addr, 0, size);
106 
107 	dev_dbg(dev, "vring%d: va %pK qsz %d notifyid %d\n",
108 		id, addr, len, rvring->notifyid);
109 
110 	/*
111 	 * Create the new vq, and tell virtio we're not interested in
112 	 * the 'weak' smp barriers, since we're talking with a real device.
113 	 */
114 	vq = vring_new_virtqueue(id, len, rvring->align, vdev, false, ctx,
115 				 addr, rproc_virtio_notify, callback, name);
116 	if (!vq) {
117 		dev_err(dev, "vring_new_virtqueue %s failed\n", name);
118 		rproc_free_vring(rvring);
119 		return ERR_PTR(-ENOMEM);
120 	}
121 
122 	rvring->vq = vq;
123 	vq->priv = rvring;
124 
125 	/* Update vring in resource table */
126 	rsc = (void *)rproc->table_ptr + rvdev->rsc_offset;
127 	rsc->vring[id].da = mem->da;
128 
129 	return vq;
130 }
131 
132 static void __rproc_virtio_del_vqs(struct virtio_device *vdev)
133 {
134 	struct virtqueue *vq, *n;
135 	struct rproc_vring *rvring;
136 
137 	list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
138 		rvring = vq->priv;
139 		rvring->vq = NULL;
140 		vring_del_virtqueue(vq);
141 	}
142 }
143 
144 static void rproc_virtio_del_vqs(struct virtio_device *vdev)
145 {
146 	__rproc_virtio_del_vqs(vdev);
147 }
148 
149 static int rproc_virtio_find_vqs(struct virtio_device *vdev, unsigned int nvqs,
150 				 struct virtqueue *vqs[],
151 				 vq_callback_t *callbacks[],
152 				 const char * const names[],
153 				 const bool * ctx,
154 				 struct irq_affinity *desc)
155 {
156 	int i, ret;
157 
158 	for (i = 0; i < nvqs; ++i) {
159 		vqs[i] = rp_find_vq(vdev, i, callbacks[i], names[i],
160 				    ctx ? ctx[i] : false);
161 		if (IS_ERR(vqs[i])) {
162 			ret = PTR_ERR(vqs[i]);
163 			goto error;
164 		}
165 	}
166 
167 	return 0;
168 
169 error:
170 	__rproc_virtio_del_vqs(vdev);
171 	return ret;
172 }
173 
174 static u8 rproc_virtio_get_status(struct virtio_device *vdev)
175 {
176 	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
177 	struct fw_rsc_vdev *rsc;
178 
179 	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
180 
181 	return rsc->status;
182 }
183 
184 static void rproc_virtio_set_status(struct virtio_device *vdev, u8 status)
185 {
186 	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
187 	struct fw_rsc_vdev *rsc;
188 
189 	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
190 
191 	rsc->status = status;
192 	dev_dbg(&vdev->dev, "status: %d\n", status);
193 }
194 
195 static void rproc_virtio_reset(struct virtio_device *vdev)
196 {
197 	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
198 	struct fw_rsc_vdev *rsc;
199 
200 	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
201 
202 	rsc->status = 0;
203 	dev_dbg(&vdev->dev, "reset !\n");
204 }
205 
206 /* provide the vdev features as retrieved from the firmware */
207 static u64 rproc_virtio_get_features(struct virtio_device *vdev)
208 {
209 	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
210 	struct fw_rsc_vdev *rsc;
211 
212 	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
213 
214 	return rsc->dfeatures;
215 }
216 
217 static void rproc_transport_features(struct virtio_device *vdev)
218 {
219 	/*
220 	 * Packed ring isn't enabled on remoteproc for now,
221 	 * because remoteproc uses vring_new_virtqueue() which
222 	 * creates virtio rings on preallocated memory.
223 	 */
224 	__virtio_clear_bit(vdev, VIRTIO_F_RING_PACKED);
225 }
226 
227 static int rproc_virtio_finalize_features(struct virtio_device *vdev)
228 {
229 	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
230 	struct fw_rsc_vdev *rsc;
231 
232 	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
233 
234 	/* Give virtio_ring a chance to accept features */
235 	vring_transport_features(vdev);
236 
237 	/* Give virtio_rproc a chance to accept features. */
238 	rproc_transport_features(vdev);
239 
240 	/* Make sure we don't have any features > 32 bits! */
241 	BUG_ON((u32)vdev->features != vdev->features);
242 
243 	/*
244 	 * Remember the finalized features of our vdev, and provide it
245 	 * to the remote processor once it is powered on.
246 	 */
247 	rsc->gfeatures = vdev->features;
248 
249 	return 0;
250 }
251 
252 static void rproc_virtio_get(struct virtio_device *vdev, unsigned int offset,
253 			     void *buf, unsigned int len)
254 {
255 	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
256 	struct fw_rsc_vdev *rsc;
257 	void *cfg;
258 
259 	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
260 	cfg = &rsc->vring[rsc->num_of_vrings];
261 
262 	if (offset + len > rsc->config_len || offset + len < len) {
263 		dev_err(&vdev->dev, "rproc_virtio_get: access out of bounds\n");
264 		return;
265 	}
266 
267 	memcpy(buf, cfg + offset, len);
268 }
269 
270 static void rproc_virtio_set(struct virtio_device *vdev, unsigned int offset,
271 			     const void *buf, unsigned int len)
272 {
273 	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
274 	struct fw_rsc_vdev *rsc;
275 	void *cfg;
276 
277 	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
278 	cfg = &rsc->vring[rsc->num_of_vrings];
279 
280 	if (offset + len > rsc->config_len || offset + len < len) {
281 		dev_err(&vdev->dev, "rproc_virtio_set: access out of bounds\n");
282 		return;
283 	}
284 
285 	memcpy(cfg + offset, buf, len);
286 }
287 
288 static const struct virtio_config_ops rproc_virtio_config_ops = {
289 	.get_features	= rproc_virtio_get_features,
290 	.finalize_features = rproc_virtio_finalize_features,
291 	.find_vqs	= rproc_virtio_find_vqs,
292 	.del_vqs	= rproc_virtio_del_vqs,
293 	.reset		= rproc_virtio_reset,
294 	.set_status	= rproc_virtio_set_status,
295 	.get_status	= rproc_virtio_get_status,
296 	.get		= rproc_virtio_get,
297 	.set		= rproc_virtio_set,
298 };
299 
300 /*
301  * This function is called whenever vdev is released, and is responsible
302  * to decrement the remote processor's refcount which was taken when vdev was
303  * added.
304  *
305  * Never call this function directly; it will be called by the driver
306  * core when needed.
307  */
308 static void rproc_virtio_dev_release(struct device *dev)
309 {
310 	struct virtio_device *vdev = dev_to_virtio(dev);
311 	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
312 	struct rproc *rproc = vdev_to_rproc(vdev);
313 
314 	kref_put(&rvdev->refcount, rproc_vdev_release);
315 
316 	put_device(&rproc->dev);
317 }
318 
319 /**
320  * rproc_add_virtio_dev() - register an rproc-induced virtio device
321  * @rvdev: the remote vdev
322  *
323  * This function registers a virtio device. This vdev's partent is
324  * the rproc device.
325  *
326  * Returns 0 on success or an appropriate error value otherwise.
327  */
328 int rproc_add_virtio_dev(struct rproc_vdev *rvdev, int id)
329 {
330 	struct rproc *rproc = rvdev->rproc;
331 	struct device *dev = &rproc->dev;
332 	struct virtio_device *vdev = &rvdev->vdev;
333 	int ret;
334 
335 	vdev->id.device	= id,
336 	vdev->config = &rproc_virtio_config_ops,
337 	vdev->dev.parent = dev;
338 	vdev->dev.release = rproc_virtio_dev_release;
339 
340 	/*
341 	 * We're indirectly making a non-temporary copy of the rproc pointer
342 	 * here, because drivers probed with this vdev will indirectly
343 	 * access the wrapping rproc.
344 	 *
345 	 * Therefore we must increment the rproc refcount here, and decrement
346 	 * it _only_ when the vdev is released.
347 	 */
348 	get_device(&rproc->dev);
349 
350 	/* Reference the vdev and vring allocations */
351 	kref_get(&rvdev->refcount);
352 
353 	ret = register_virtio_device(vdev);
354 	if (ret) {
355 		put_device(&vdev->dev);
356 		dev_err(dev, "failed to register vdev: %d\n", ret);
357 		goto out;
358 	}
359 
360 	dev_info(dev, "registered %s (type %d)\n", dev_name(&vdev->dev), id);
361 
362 out:
363 	return ret;
364 }
365 
366 /**
367  * rproc_remove_virtio_dev() - remove an rproc-induced virtio device
368  * @rvdev: the remote vdev
369  *
370  * This function unregisters an existing virtio device.
371  */
372 void rproc_remove_virtio_dev(struct rproc_vdev *rvdev)
373 {
374 	unregister_virtio_device(&rvdev->vdev);
375 }
376