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/dma-mapping.h>
21 #include <linux/export.h>
22 #include <linux/of_reserved_mem.h>
23 #include <linux/remoteproc.h>
24 #include <linux/virtio.h>
25 #include <linux/virtio_config.h>
26 #include <linux/virtio_ids.h>
27 #include <linux/virtio_ring.h>
28 #include <linux/err.h>
29 #include <linux/kref.h>
30 #include <linux/slab.h>
31 
32 #include "remoteproc_internal.h"
33 
34 /* kick the remote processor, and let it know which virtqueue to poke at */
35 static bool rproc_virtio_notify(struct virtqueue *vq)
36 {
37 	struct rproc_vring *rvring = vq->priv;
38 	struct rproc *rproc = rvring->rvdev->rproc;
39 	int notifyid = rvring->notifyid;
40 
41 	dev_dbg(&rproc->dev, "kicking vq index: %d\n", notifyid);
42 
43 	rproc->ops->kick(rproc, notifyid);
44 	return true;
45 }
46 
47 /**
48  * rproc_vq_interrupt() - tell remoteproc that a virtqueue is interrupted
49  * @rproc: handle to the remote processor
50  * @notifyid: index of the signalled virtqueue (unique per this @rproc)
51  *
52  * This function should be called by the platform-specific rproc driver,
53  * when the remote processor signals that a specific virtqueue has pending
54  * messages available.
55  *
56  * Returns IRQ_NONE if no message was found in the @notifyid virtqueue,
57  * and otherwise returns IRQ_HANDLED.
58  */
59 irqreturn_t rproc_vq_interrupt(struct rproc *rproc, int notifyid)
60 {
61 	struct rproc_vring *rvring;
62 
63 	dev_dbg(&rproc->dev, "vq index %d is interrupted\n", notifyid);
64 
65 	rvring = idr_find(&rproc->notifyids, notifyid);
66 	if (!rvring || !rvring->vq)
67 		return IRQ_NONE;
68 
69 	return vring_interrupt(0, rvring->vq);
70 }
71 EXPORT_SYMBOL(rproc_vq_interrupt);
72 
73 static struct virtqueue *rp_find_vq(struct virtio_device *vdev,
74 				    unsigned int id,
75 				    void (*callback)(struct virtqueue *vq),
76 				    const char *name, bool ctx)
77 {
78 	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
79 	struct rproc *rproc = vdev_to_rproc(vdev);
80 	struct device *dev = &rproc->dev;
81 	struct rproc_mem_entry *mem;
82 	struct rproc_vring *rvring;
83 	struct fw_rsc_vdev *rsc;
84 	struct virtqueue *vq;
85 	void *addr;
86 	int len, size;
87 
88 	/* we're temporarily limited to two virtqueues per rvdev */
89 	if (id >= ARRAY_SIZE(rvdev->vring))
90 		return ERR_PTR(-EINVAL);
91 
92 	if (!name)
93 		return NULL;
94 
95 	/* Search allocated memory region by name */
96 	mem = rproc_find_carveout_by_name(rproc, "vdev%dvring%d", rvdev->index,
97 					  id);
98 	if (!mem || !mem->va)
99 		return ERR_PTR(-ENOMEM);
100 
101 	rvring = &rvdev->vring[id];
102 	addr = mem->va;
103 	len = rvring->len;
104 
105 	/* zero vring */
106 	size = vring_size(len, rvring->align);
107 	memset(addr, 0, size);
108 
109 	dev_dbg(dev, "vring%d: va %pK qsz %d notifyid %d\n",
110 		id, addr, len, rvring->notifyid);
111 
112 	/*
113 	 * Create the new vq, and tell virtio we're not interested in
114 	 * the 'weak' smp barriers, since we're talking with a real device.
115 	 */
116 	vq = vring_new_virtqueue(id, len, rvring->align, vdev, false, ctx,
117 				 addr, rproc_virtio_notify, callback, name);
118 	if (!vq) {
119 		dev_err(dev, "vring_new_virtqueue %s failed\n", name);
120 		rproc_free_vring(rvring);
121 		return ERR_PTR(-ENOMEM);
122 	}
123 
124 	rvring->vq = vq;
125 	vq->priv = rvring;
126 
127 	/* Update vring in resource table */
128 	rsc = (void *)rproc->table_ptr + rvdev->rsc_offset;
129 	rsc->vring[id].da = mem->da;
130 
131 	return vq;
132 }
133 
134 static void __rproc_virtio_del_vqs(struct virtio_device *vdev)
135 {
136 	struct virtqueue *vq, *n;
137 	struct rproc_vring *rvring;
138 
139 	list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
140 		rvring = vq->priv;
141 		rvring->vq = NULL;
142 		vring_del_virtqueue(vq);
143 	}
144 }
145 
146 static void rproc_virtio_del_vqs(struct virtio_device *vdev)
147 {
148 	__rproc_virtio_del_vqs(vdev);
149 }
150 
151 static int rproc_virtio_find_vqs(struct virtio_device *vdev, unsigned int nvqs,
152 				 struct virtqueue *vqs[],
153 				 vq_callback_t *callbacks[],
154 				 const char * const names[],
155 				 const bool * ctx,
156 				 struct irq_affinity *desc)
157 {
158 	int i, ret, queue_idx = 0;
159 
160 	for (i = 0; i < nvqs; ++i) {
161 		if (!names[i]) {
162 			vqs[i] = NULL;
163 			continue;
164 		}
165 
166 		vqs[i] = rp_find_vq(vdev, queue_idx++, callbacks[i], names[i],
167 				    ctx ? ctx[i] : false);
168 		if (IS_ERR(vqs[i])) {
169 			ret = PTR_ERR(vqs[i]);
170 			goto error;
171 		}
172 	}
173 
174 	return 0;
175 
176 error:
177 	__rproc_virtio_del_vqs(vdev);
178 	return ret;
179 }
180 
181 static u8 rproc_virtio_get_status(struct virtio_device *vdev)
182 {
183 	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
184 	struct fw_rsc_vdev *rsc;
185 
186 	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
187 
188 	return rsc->status;
189 }
190 
191 static void rproc_virtio_set_status(struct virtio_device *vdev, u8 status)
192 {
193 	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
194 	struct fw_rsc_vdev *rsc;
195 
196 	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
197 
198 	rsc->status = status;
199 	dev_dbg(&vdev->dev, "status: %d\n", status);
200 }
201 
202 static void rproc_virtio_reset(struct virtio_device *vdev)
203 {
204 	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
205 	struct fw_rsc_vdev *rsc;
206 
207 	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
208 
209 	rsc->status = 0;
210 	dev_dbg(&vdev->dev, "reset !\n");
211 }
212 
213 /* provide the vdev features as retrieved from the firmware */
214 static u64 rproc_virtio_get_features(struct virtio_device *vdev)
215 {
216 	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
217 	struct fw_rsc_vdev *rsc;
218 
219 	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
220 
221 	return rsc->dfeatures;
222 }
223 
224 static void rproc_transport_features(struct virtio_device *vdev)
225 {
226 	/*
227 	 * Packed ring isn't enabled on remoteproc for now,
228 	 * because remoteproc uses vring_new_virtqueue() which
229 	 * creates virtio rings on preallocated memory.
230 	 */
231 	__virtio_clear_bit(vdev, VIRTIO_F_RING_PACKED);
232 }
233 
234 static int rproc_virtio_finalize_features(struct virtio_device *vdev)
235 {
236 	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
237 	struct fw_rsc_vdev *rsc;
238 
239 	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
240 
241 	/* Give virtio_ring a chance to accept features */
242 	vring_transport_features(vdev);
243 
244 	/* Give virtio_rproc a chance to accept features. */
245 	rproc_transport_features(vdev);
246 
247 	/* Make sure we don't have any features > 32 bits! */
248 	BUG_ON((u32)vdev->features != vdev->features);
249 
250 	/*
251 	 * Remember the finalized features of our vdev, and provide it
252 	 * to the remote processor once it is powered on.
253 	 */
254 	rsc->gfeatures = vdev->features;
255 
256 	return 0;
257 }
258 
259 static void rproc_virtio_get(struct virtio_device *vdev, unsigned int offset,
260 			     void *buf, unsigned int len)
261 {
262 	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
263 	struct fw_rsc_vdev *rsc;
264 	void *cfg;
265 
266 	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
267 	cfg = &rsc->vring[rsc->num_of_vrings];
268 
269 	if (offset + len > rsc->config_len || offset + len < len) {
270 		dev_err(&vdev->dev, "rproc_virtio_get: access out of bounds\n");
271 		return;
272 	}
273 
274 	memcpy(buf, cfg + offset, len);
275 }
276 
277 static void rproc_virtio_set(struct virtio_device *vdev, unsigned int offset,
278 			     const void *buf, unsigned int len)
279 {
280 	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
281 	struct fw_rsc_vdev *rsc;
282 	void *cfg;
283 
284 	rsc = (void *)rvdev->rproc->table_ptr + rvdev->rsc_offset;
285 	cfg = &rsc->vring[rsc->num_of_vrings];
286 
287 	if (offset + len > rsc->config_len || offset + len < len) {
288 		dev_err(&vdev->dev, "rproc_virtio_set: access out of bounds\n");
289 		return;
290 	}
291 
292 	memcpy(cfg + offset, buf, len);
293 }
294 
295 static const struct virtio_config_ops rproc_virtio_config_ops = {
296 	.get_features	= rproc_virtio_get_features,
297 	.finalize_features = rproc_virtio_finalize_features,
298 	.find_vqs	= rproc_virtio_find_vqs,
299 	.del_vqs	= rproc_virtio_del_vqs,
300 	.reset		= rproc_virtio_reset,
301 	.set_status	= rproc_virtio_set_status,
302 	.get_status	= rproc_virtio_get_status,
303 	.get		= rproc_virtio_get,
304 	.set		= rproc_virtio_set,
305 };
306 
307 /*
308  * This function is called whenever vdev is released, and is responsible
309  * to decrement the remote processor's refcount which was taken when vdev was
310  * added.
311  *
312  * Never call this function directly; it will be called by the driver
313  * core when needed.
314  */
315 static void rproc_virtio_dev_release(struct device *dev)
316 {
317 	struct virtio_device *vdev = dev_to_virtio(dev);
318 	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
319 	struct rproc *rproc = vdev_to_rproc(vdev);
320 
321 	kfree(vdev);
322 
323 	kref_put(&rvdev->refcount, rproc_vdev_release);
324 
325 	put_device(&rproc->dev);
326 }
327 
328 /**
329  * rproc_add_virtio_dev() - register an rproc-induced virtio device
330  * @rvdev: the remote vdev
331  *
332  * This function registers a virtio device. This vdev's partent is
333  * the rproc device.
334  *
335  * Returns 0 on success or an appropriate error value otherwise.
336  */
337 int rproc_add_virtio_dev(struct rproc_vdev *rvdev, int id)
338 {
339 	struct rproc *rproc = rvdev->rproc;
340 	struct device *dev = &rvdev->dev;
341 	struct virtio_device *vdev;
342 	struct rproc_mem_entry *mem;
343 	int ret;
344 
345 	/* Try to find dedicated vdev buffer carveout */
346 	mem = rproc_find_carveout_by_name(rproc, "vdev%dbuffer", rvdev->index);
347 	if (mem) {
348 		phys_addr_t pa;
349 
350 		if (mem->of_resm_idx != -1) {
351 			struct device_node *np = rproc->dev.parent->of_node;
352 
353 			/* Associate reserved memory to vdev device */
354 			ret = of_reserved_mem_device_init_by_idx(dev, np,
355 								 mem->of_resm_idx);
356 			if (ret) {
357 				dev_err(dev, "Can't associate reserved memory\n");
358 				goto out;
359 			}
360 		} else {
361 			if (mem->va) {
362 				dev_warn(dev, "vdev %d buffer already mapped\n",
363 					 rvdev->index);
364 				pa = rproc_va_to_pa(mem->va);
365 			} else {
366 				/* Use dma address as carveout no memmapped yet */
367 				pa = (phys_addr_t)mem->dma;
368 			}
369 
370 			/* Associate vdev buffer memory pool to vdev subdev */
371 			ret = dma_declare_coherent_memory(dev, pa,
372 							   mem->da,
373 							   mem->len);
374 			if (ret < 0) {
375 				dev_err(dev, "Failed to associate buffer\n");
376 				goto out;
377 			}
378 		}
379 	}
380 
381 	/* Allocate virtio device */
382 	vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
383 	if (!vdev) {
384 		ret = -ENOMEM;
385 		goto out;
386 	}
387 	vdev->id.device	= id,
388 	vdev->config = &rproc_virtio_config_ops,
389 	vdev->dev.parent = dev;
390 	vdev->dev.release = rproc_virtio_dev_release;
391 
392 	/*
393 	 * We're indirectly making a non-temporary copy of the rproc pointer
394 	 * here, because drivers probed with this vdev will indirectly
395 	 * access the wrapping rproc.
396 	 *
397 	 * Therefore we must increment the rproc refcount here, and decrement
398 	 * it _only_ when the vdev is released.
399 	 */
400 	get_device(&rproc->dev);
401 
402 	/* Reference the vdev and vring allocations */
403 	kref_get(&rvdev->refcount);
404 
405 	ret = register_virtio_device(vdev);
406 	if (ret) {
407 		put_device(&vdev->dev);
408 		dev_err(dev, "failed to register vdev: %d\n", ret);
409 		goto out;
410 	}
411 
412 	dev_info(dev, "registered %s (type %d)\n", dev_name(&vdev->dev), id);
413 
414 out:
415 	return ret;
416 }
417 
418 /**
419  * rproc_remove_virtio_dev() - remove an rproc-induced virtio device
420  * @dev: the virtio device
421  * @data: must be null
422  *
423  * This function unregisters an existing virtio device.
424  */
425 int rproc_remove_virtio_dev(struct device *dev, void *data)
426 {
427 	struct virtio_device *vdev = dev_to_virtio(dev);
428 
429 	unregister_virtio_device(vdev);
430 	return 0;
431 }
432