1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Virtio-based remote processor messaging bus |
4 | * |
5 | * Copyright (C) 2011 Texas Instruments, Inc. |
6 | * Copyright (C) 2011 Google, Inc. |
7 | * |
8 | * Ohad Ben-Cohen <ohad@wizery.com> |
9 | * Brian Swetland <swetland@google.com> |
10 | */ |
11 | |
12 | #define pr_fmt(fmt) "%s: " fmt, __func__ |
13 | |
14 | #include <linux/dma-mapping.h> |
15 | #include <linux/idr.h> |
16 | #include <linux/jiffies.h> |
17 | #include <linux/kernel.h> |
18 | #include <linux/module.h> |
19 | #include <linux/mutex.h> |
20 | #include <linux/rpmsg.h> |
21 | #include <linux/rpmsg/byteorder.h> |
22 | #include <linux/rpmsg/ns.h> |
23 | #include <linux/scatterlist.h> |
24 | #include <linux/slab.h> |
25 | #include <linux/sched.h> |
26 | #include <linux/virtio.h> |
27 | #include <linux/virtio_ids.h> |
28 | #include <linux/virtio_config.h> |
29 | #include <linux/wait.h> |
30 | |
31 | #include "rpmsg_internal.h" |
32 | |
33 | /** |
34 | * struct virtproc_info - virtual remote processor state |
35 | * @vdev: the virtio device |
36 | * @rvq: rx virtqueue |
37 | * @svq: tx virtqueue |
38 | * @rbufs: kernel address of rx buffers |
39 | * @sbufs: kernel address of tx buffers |
40 | * @num_bufs: total number of buffers for rx and tx |
41 | * @buf_size: size of one rx or tx buffer |
42 | * @last_sbuf: index of last tx buffer used |
43 | * @bufs_dma: dma base addr of the buffers |
44 | * @tx_lock: protects svq, sbufs and sleepers, to allow concurrent senders. |
45 | * sending a message might require waking up a dozing remote |
46 | * processor, which involves sleeping, hence the mutex. |
47 | * @endpoints: idr of local endpoints, allows fast retrieval |
48 | * @endpoints_lock: lock of the endpoints set |
49 | * @sendq: wait queue of sending contexts waiting for a tx buffers |
50 | * @sleepers: number of senders that are waiting for a tx buffer |
51 | * |
52 | * This structure stores the rpmsg state of a given virtio remote processor |
53 | * device (there might be several virtio proc devices for each physical |
54 | * remote processor). |
55 | */ |
56 | struct virtproc_info { |
57 | struct virtio_device *vdev; |
58 | struct virtqueue *rvq, *svq; |
59 | void *rbufs, *sbufs; |
60 | unsigned int num_bufs; |
61 | unsigned int buf_size; |
62 | int last_sbuf; |
63 | dma_addr_t bufs_dma; |
64 | struct mutex tx_lock; |
65 | struct idr endpoints; |
66 | struct mutex endpoints_lock; |
67 | wait_queue_head_t sendq; |
68 | atomic_t sleepers; |
69 | }; |
70 | |
71 | /* The feature bitmap for virtio rpmsg */ |
72 | #define VIRTIO_RPMSG_F_NS 0 /* RP supports name service notifications */ |
73 | |
74 | /** |
75 | * struct rpmsg_hdr - common header for all rpmsg messages |
76 | * @src: source address |
77 | * @dst: destination address |
78 | * @reserved: reserved for future use |
79 | * @len: length of payload (in bytes) |
80 | * @flags: message flags |
81 | * @data: @len bytes of message payload data |
82 | * |
83 | * Every message sent(/received) on the rpmsg bus begins with this header. |
84 | */ |
85 | struct rpmsg_hdr { |
86 | __rpmsg32 src; |
87 | __rpmsg32 dst; |
88 | __rpmsg32 reserved; |
89 | __rpmsg16 len; |
90 | __rpmsg16 flags; |
91 | u8 data[]; |
92 | } __packed; |
93 | |
94 | |
95 | /** |
96 | * struct virtio_rpmsg_channel - rpmsg channel descriptor |
97 | * @rpdev: the rpmsg channel device |
98 | * @vrp: the virtio remote processor device this channel belongs to |
99 | * |
100 | * This structure stores the channel that links the rpmsg device to the virtio |
101 | * remote processor device. |
102 | */ |
103 | struct virtio_rpmsg_channel { |
104 | struct rpmsg_device rpdev; |
105 | |
106 | struct virtproc_info *vrp; |
107 | }; |
108 | |
109 | #define to_virtio_rpmsg_channel(_rpdev) \ |
110 | container_of(_rpdev, struct virtio_rpmsg_channel, rpdev) |
111 | |
112 | /* |
113 | * We're allocating buffers of 512 bytes each for communications. The |
114 | * number of buffers will be computed from the number of buffers supported |
115 | * by the vring, upto a maximum of 512 buffers (256 in each direction). |
116 | * |
117 | * Each buffer will have 16 bytes for the msg header and 496 bytes for |
118 | * the payload. |
119 | * |
120 | * This will utilize a maximum total space of 256KB for the buffers. |
121 | * |
122 | * We might also want to add support for user-provided buffers in time. |
123 | * This will allow bigger buffer size flexibility, and can also be used |
124 | * to achieve zero-copy messaging. |
125 | * |
126 | * Note that these numbers are purely a decision of this driver - we |
127 | * can change this without changing anything in the firmware of the remote |
128 | * processor. |
129 | */ |
130 | #define MAX_RPMSG_NUM_BUFS (512) |
131 | #define MAX_RPMSG_BUF_SIZE (512) |
132 | |
133 | /* |
134 | * Local addresses are dynamically allocated on-demand. |
135 | * We do not dynamically assign addresses from the low 1024 range, |
136 | * in order to reserve that address range for predefined services. |
137 | */ |
138 | #define RPMSG_RESERVED_ADDRESSES (1024) |
139 | |
140 | static void virtio_rpmsg_destroy_ept(struct rpmsg_endpoint *ept); |
141 | static int virtio_rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len); |
142 | static int virtio_rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len, |
143 | u32 dst); |
144 | static int virtio_rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src, |
145 | u32 dst, void *data, int len); |
146 | static int virtio_rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len); |
147 | static int virtio_rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data, |
148 | int len, u32 dst); |
149 | static int virtio_rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, |
150 | u32 dst, void *data, int len); |
151 | static ssize_t virtio_rpmsg_get_mtu(struct rpmsg_endpoint *ept); |
152 | static struct rpmsg_device *__rpmsg_create_channel(struct virtproc_info *vrp, |
153 | struct rpmsg_channel_info *chinfo); |
154 | |
155 | static const struct rpmsg_endpoint_ops virtio_endpoint_ops = { |
156 | .destroy_ept = virtio_rpmsg_destroy_ept, |
157 | .send = virtio_rpmsg_send, |
158 | .sendto = virtio_rpmsg_sendto, |
159 | .send_offchannel = virtio_rpmsg_send_offchannel, |
160 | .trysend = virtio_rpmsg_trysend, |
161 | .trysendto = virtio_rpmsg_trysendto, |
162 | .trysend_offchannel = virtio_rpmsg_trysend_offchannel, |
163 | .get_mtu = virtio_rpmsg_get_mtu, |
164 | }; |
165 | |
166 | /** |
167 | * rpmsg_sg_init - initialize scatterlist according to cpu address location |
168 | * @sg: scatterlist to fill |
169 | * @cpu_addr: virtual address of the buffer |
170 | * @len: buffer length |
171 | * |
172 | * An internal function filling scatterlist according to virtual address |
173 | * location (in vmalloc or in kernel). |
174 | */ |
175 | static void |
176 | rpmsg_sg_init(struct scatterlist *sg, void *cpu_addr, unsigned int len) |
177 | { |
178 | if (is_vmalloc_addr(x: cpu_addr)) { |
179 | sg_init_table(sg, 1); |
180 | sg_set_page(sg, page: vmalloc_to_page(addr: cpu_addr), len, |
181 | offset_in_page(cpu_addr)); |
182 | } else { |
183 | WARN_ON(!virt_addr_valid(cpu_addr)); |
184 | sg_init_one(sg, cpu_addr, len); |
185 | } |
186 | } |
187 | |
188 | /** |
189 | * __ept_release() - deallocate an rpmsg endpoint |
190 | * @kref: the ept's reference count |
191 | * |
192 | * This function deallocates an ept, and is invoked when its @kref refcount |
193 | * drops to zero. |
194 | * |
195 | * Never invoke this function directly! |
196 | */ |
197 | static void __ept_release(struct kref *kref) |
198 | { |
199 | struct rpmsg_endpoint *ept = container_of(kref, struct rpmsg_endpoint, |
200 | refcount); |
201 | /* |
202 | * At this point no one holds a reference to ept anymore, |
203 | * so we can directly free it |
204 | */ |
205 | kfree(objp: ept); |
206 | } |
207 | |
208 | /* for more info, see below documentation of rpmsg_create_ept() */ |
209 | static struct rpmsg_endpoint *__rpmsg_create_ept(struct virtproc_info *vrp, |
210 | struct rpmsg_device *rpdev, |
211 | rpmsg_rx_cb_t cb, |
212 | void *priv, u32 addr) |
213 | { |
214 | int id_min, id_max, id; |
215 | struct rpmsg_endpoint *ept; |
216 | struct device *dev = rpdev ? &rpdev->dev : &vrp->vdev->dev; |
217 | |
218 | ept = kzalloc(size: sizeof(*ept), GFP_KERNEL); |
219 | if (!ept) |
220 | return NULL; |
221 | |
222 | kref_init(kref: &ept->refcount); |
223 | mutex_init(&ept->cb_lock); |
224 | |
225 | ept->rpdev = rpdev; |
226 | ept->cb = cb; |
227 | ept->priv = priv; |
228 | ept->ops = &virtio_endpoint_ops; |
229 | |
230 | /* do we need to allocate a local address ? */ |
231 | if (addr == RPMSG_ADDR_ANY) { |
232 | id_min = RPMSG_RESERVED_ADDRESSES; |
233 | id_max = 0; |
234 | } else { |
235 | id_min = addr; |
236 | id_max = addr + 1; |
237 | } |
238 | |
239 | mutex_lock(&vrp->endpoints_lock); |
240 | |
241 | /* bind the endpoint to an rpmsg address (and allocate one if needed) */ |
242 | id = idr_alloc(&vrp->endpoints, ptr: ept, start: id_min, end: id_max, GFP_KERNEL); |
243 | if (id < 0) { |
244 | dev_err(dev, "idr_alloc failed: %d\n" , id); |
245 | goto free_ept; |
246 | } |
247 | ept->addr = id; |
248 | |
249 | mutex_unlock(lock: &vrp->endpoints_lock); |
250 | |
251 | return ept; |
252 | |
253 | free_ept: |
254 | mutex_unlock(lock: &vrp->endpoints_lock); |
255 | kref_put(kref: &ept->refcount, release: __ept_release); |
256 | return NULL; |
257 | } |
258 | |
259 | static struct rpmsg_device *virtio_rpmsg_create_channel(struct rpmsg_device *rpdev, |
260 | struct rpmsg_channel_info *chinfo) |
261 | { |
262 | struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev); |
263 | struct virtproc_info *vrp = vch->vrp; |
264 | |
265 | return __rpmsg_create_channel(vrp, chinfo); |
266 | } |
267 | |
268 | static int virtio_rpmsg_release_channel(struct rpmsg_device *rpdev, |
269 | struct rpmsg_channel_info *chinfo) |
270 | { |
271 | struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev); |
272 | struct virtproc_info *vrp = vch->vrp; |
273 | |
274 | return rpmsg_unregister_device(parent: &vrp->vdev->dev, chinfo); |
275 | } |
276 | |
277 | static struct rpmsg_endpoint *virtio_rpmsg_create_ept(struct rpmsg_device *rpdev, |
278 | rpmsg_rx_cb_t cb, |
279 | void *priv, |
280 | struct rpmsg_channel_info chinfo) |
281 | { |
282 | struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev); |
283 | |
284 | return __rpmsg_create_ept(vrp: vch->vrp, rpdev, cb, priv, addr: chinfo.src); |
285 | } |
286 | |
287 | /** |
288 | * __rpmsg_destroy_ept() - destroy an existing rpmsg endpoint |
289 | * @vrp: virtproc which owns this ept |
290 | * @ept: endpoing to destroy |
291 | * |
292 | * An internal function which destroy an ept without assuming it is |
293 | * bound to an rpmsg channel. This is needed for handling the internal |
294 | * name service endpoint, which isn't bound to an rpmsg channel. |
295 | * See also __rpmsg_create_ept(). |
296 | */ |
297 | static void |
298 | __rpmsg_destroy_ept(struct virtproc_info *vrp, struct rpmsg_endpoint *ept) |
299 | { |
300 | /* make sure new inbound messages can't find this ept anymore */ |
301 | mutex_lock(&vrp->endpoints_lock); |
302 | idr_remove(&vrp->endpoints, id: ept->addr); |
303 | mutex_unlock(lock: &vrp->endpoints_lock); |
304 | |
305 | /* make sure in-flight inbound messages won't invoke cb anymore */ |
306 | mutex_lock(&ept->cb_lock); |
307 | ept->cb = NULL; |
308 | mutex_unlock(lock: &ept->cb_lock); |
309 | |
310 | kref_put(kref: &ept->refcount, release: __ept_release); |
311 | } |
312 | |
313 | static void virtio_rpmsg_destroy_ept(struct rpmsg_endpoint *ept) |
314 | { |
315 | struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(ept->rpdev); |
316 | |
317 | __rpmsg_destroy_ept(vrp: vch->vrp, ept); |
318 | } |
319 | |
320 | static int virtio_rpmsg_announce_create(struct rpmsg_device *rpdev) |
321 | { |
322 | struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev); |
323 | struct virtproc_info *vrp = vch->vrp; |
324 | struct device *dev = &rpdev->dev; |
325 | int err = 0; |
326 | |
327 | /* need to tell remote processor's name service about this channel ? */ |
328 | if (rpdev->announce && rpdev->ept && |
329 | virtio_has_feature(vdev: vrp->vdev, VIRTIO_RPMSG_F_NS)) { |
330 | struct rpmsg_ns_msg nsm; |
331 | |
332 | strscpy_pad(nsm.name, rpdev->id.name, sizeof(nsm.name)); |
333 | nsm.addr = cpu_to_rpmsg32(rpdev, val: rpdev->ept->addr); |
334 | nsm.flags = cpu_to_rpmsg32(rpdev, val: RPMSG_NS_CREATE); |
335 | |
336 | err = rpmsg_sendto(ept: rpdev->ept, data: &nsm, len: sizeof(nsm), RPMSG_NS_ADDR); |
337 | if (err) |
338 | dev_err(dev, "failed to announce service %d\n" , err); |
339 | } |
340 | |
341 | return err; |
342 | } |
343 | |
344 | static int virtio_rpmsg_announce_destroy(struct rpmsg_device *rpdev) |
345 | { |
346 | struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev); |
347 | struct virtproc_info *vrp = vch->vrp; |
348 | struct device *dev = &rpdev->dev; |
349 | int err = 0; |
350 | |
351 | /* tell remote processor's name service we're removing this channel */ |
352 | if (rpdev->announce && rpdev->ept && |
353 | virtio_has_feature(vdev: vrp->vdev, VIRTIO_RPMSG_F_NS)) { |
354 | struct rpmsg_ns_msg nsm; |
355 | |
356 | strscpy_pad(nsm.name, rpdev->id.name, sizeof(nsm.name)); |
357 | nsm.addr = cpu_to_rpmsg32(rpdev, val: rpdev->ept->addr); |
358 | nsm.flags = cpu_to_rpmsg32(rpdev, val: RPMSG_NS_DESTROY); |
359 | |
360 | err = rpmsg_sendto(ept: rpdev->ept, data: &nsm, len: sizeof(nsm), RPMSG_NS_ADDR); |
361 | if (err) |
362 | dev_err(dev, "failed to announce service %d\n" , err); |
363 | } |
364 | |
365 | return err; |
366 | } |
367 | |
368 | static const struct rpmsg_device_ops virtio_rpmsg_ops = { |
369 | .create_channel = virtio_rpmsg_create_channel, |
370 | .release_channel = virtio_rpmsg_release_channel, |
371 | .create_ept = virtio_rpmsg_create_ept, |
372 | .announce_create = virtio_rpmsg_announce_create, |
373 | .announce_destroy = virtio_rpmsg_announce_destroy, |
374 | }; |
375 | |
376 | static void virtio_rpmsg_release_device(struct device *dev) |
377 | { |
378 | struct rpmsg_device *rpdev = to_rpmsg_device(dev); |
379 | struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev); |
380 | |
381 | kfree(objp: rpdev->driver_override); |
382 | kfree(objp: vch); |
383 | } |
384 | |
385 | /* |
386 | * create an rpmsg channel using its name and address info. |
387 | * this function will be used to create both static and dynamic |
388 | * channels. |
389 | */ |
390 | static struct rpmsg_device *__rpmsg_create_channel(struct virtproc_info *vrp, |
391 | struct rpmsg_channel_info *chinfo) |
392 | { |
393 | struct virtio_rpmsg_channel *vch; |
394 | struct rpmsg_device *rpdev; |
395 | struct device *tmp, *dev = &vrp->vdev->dev; |
396 | int ret; |
397 | |
398 | /* make sure a similar channel doesn't already exist */ |
399 | tmp = rpmsg_find_device(parent: dev, chinfo); |
400 | if (tmp) { |
401 | /* decrement the matched device's refcount back */ |
402 | put_device(dev: tmp); |
403 | dev_err(dev, "channel %s:%x:%x already exist\n" , |
404 | chinfo->name, chinfo->src, chinfo->dst); |
405 | return NULL; |
406 | } |
407 | |
408 | vch = kzalloc(size: sizeof(*vch), GFP_KERNEL); |
409 | if (!vch) |
410 | return NULL; |
411 | |
412 | /* Link the channel to our vrp */ |
413 | vch->vrp = vrp; |
414 | |
415 | /* Assign public information to the rpmsg_device */ |
416 | rpdev = &vch->rpdev; |
417 | rpdev->src = chinfo->src; |
418 | rpdev->dst = chinfo->dst; |
419 | rpdev->ops = &virtio_rpmsg_ops; |
420 | rpdev->little_endian = virtio_is_little_endian(vdev: vrp->vdev); |
421 | |
422 | /* |
423 | * rpmsg server channels has predefined local address (for now), |
424 | * and their existence needs to be announced remotely |
425 | */ |
426 | rpdev->announce = rpdev->src != RPMSG_ADDR_ANY; |
427 | |
428 | strscpy(rpdev->id.name, chinfo->name, sizeof(rpdev->id.name)); |
429 | |
430 | rpdev->dev.parent = &vrp->vdev->dev; |
431 | rpdev->dev.release = virtio_rpmsg_release_device; |
432 | ret = rpmsg_register_device(rpdev); |
433 | if (ret) |
434 | return NULL; |
435 | |
436 | return rpdev; |
437 | } |
438 | |
439 | /* super simple buffer "allocator" that is just enough for now */ |
440 | static void *get_a_tx_buf(struct virtproc_info *vrp) |
441 | { |
442 | unsigned int len; |
443 | void *ret; |
444 | |
445 | /* support multiple concurrent senders */ |
446 | mutex_lock(&vrp->tx_lock); |
447 | |
448 | /* |
449 | * either pick the next unused tx buffer |
450 | * (half of our buffers are used for sending messages) |
451 | */ |
452 | if (vrp->last_sbuf < vrp->num_bufs / 2) |
453 | ret = vrp->sbufs + vrp->buf_size * vrp->last_sbuf++; |
454 | /* or recycle a used one */ |
455 | else |
456 | ret = virtqueue_get_buf(vq: vrp->svq, len: &len); |
457 | |
458 | mutex_unlock(lock: &vrp->tx_lock); |
459 | |
460 | return ret; |
461 | } |
462 | |
463 | /** |
464 | * rpmsg_upref_sleepers() - enable "tx-complete" interrupts, if needed |
465 | * @vrp: virtual remote processor state |
466 | * |
467 | * This function is called before a sender is blocked, waiting for |
468 | * a tx buffer to become available. |
469 | * |
470 | * If we already have blocking senders, this function merely increases |
471 | * the "sleepers" reference count, and exits. |
472 | * |
473 | * Otherwise, if this is the first sender to block, we also enable |
474 | * virtio's tx callbacks, so we'd be immediately notified when a tx |
475 | * buffer is consumed (we rely on virtio's tx callback in order |
476 | * to wake up sleeping senders as soon as a tx buffer is used by the |
477 | * remote processor). |
478 | */ |
479 | static void rpmsg_upref_sleepers(struct virtproc_info *vrp) |
480 | { |
481 | /* support multiple concurrent senders */ |
482 | mutex_lock(&vrp->tx_lock); |
483 | |
484 | /* are we the first sleeping context waiting for tx buffers ? */ |
485 | if (atomic_inc_return(v: &vrp->sleepers) == 1) |
486 | /* enable "tx-complete" interrupts before dozing off */ |
487 | virtqueue_enable_cb(vq: vrp->svq); |
488 | |
489 | mutex_unlock(lock: &vrp->tx_lock); |
490 | } |
491 | |
492 | /** |
493 | * rpmsg_downref_sleepers() - disable "tx-complete" interrupts, if needed |
494 | * @vrp: virtual remote processor state |
495 | * |
496 | * This function is called after a sender, that waited for a tx buffer |
497 | * to become available, is unblocked. |
498 | * |
499 | * If we still have blocking senders, this function merely decreases |
500 | * the "sleepers" reference count, and exits. |
501 | * |
502 | * Otherwise, if there are no more blocking senders, we also disable |
503 | * virtio's tx callbacks, to avoid the overhead incurred with handling |
504 | * those (now redundant) interrupts. |
505 | */ |
506 | static void rpmsg_downref_sleepers(struct virtproc_info *vrp) |
507 | { |
508 | /* support multiple concurrent senders */ |
509 | mutex_lock(&vrp->tx_lock); |
510 | |
511 | /* are we the last sleeping context waiting for tx buffers ? */ |
512 | if (atomic_dec_and_test(v: &vrp->sleepers)) |
513 | /* disable "tx-complete" interrupts */ |
514 | virtqueue_disable_cb(vq: vrp->svq); |
515 | |
516 | mutex_unlock(lock: &vrp->tx_lock); |
517 | } |
518 | |
519 | /** |
520 | * rpmsg_send_offchannel_raw() - send a message across to the remote processor |
521 | * @rpdev: the rpmsg channel |
522 | * @src: source address |
523 | * @dst: destination address |
524 | * @data: payload of message |
525 | * @len: length of payload |
526 | * @wait: indicates whether caller should block in case no TX buffers available |
527 | * |
528 | * This function is the base implementation for all of the rpmsg sending API. |
529 | * |
530 | * It will send @data of length @len to @dst, and say it's from @src. The |
531 | * message will be sent to the remote processor which the @rpdev channel |
532 | * belongs to. |
533 | * |
534 | * The message is sent using one of the TX buffers that are available for |
535 | * communication with this remote processor. |
536 | * |
537 | * If @wait is true, the caller will be blocked until either a TX buffer is |
538 | * available, or 15 seconds elapses (we don't want callers to |
539 | * sleep indefinitely due to misbehaving remote processors), and in that |
540 | * case -ERESTARTSYS is returned. The number '15' itself was picked |
541 | * arbitrarily; there's little point in asking drivers to provide a timeout |
542 | * value themselves. |
543 | * |
544 | * Otherwise, if @wait is false, and there are no TX buffers available, |
545 | * the function will immediately fail, and -ENOMEM will be returned. |
546 | * |
547 | * Normally drivers shouldn't use this function directly; instead, drivers |
548 | * should use the appropriate rpmsg_{try}send{to, _offchannel} API |
549 | * (see include/linux/rpmsg.h). |
550 | * |
551 | * Return: 0 on success and an appropriate error value on failure. |
552 | */ |
553 | static int rpmsg_send_offchannel_raw(struct rpmsg_device *rpdev, |
554 | u32 src, u32 dst, |
555 | void *data, int len, bool wait) |
556 | { |
557 | struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev); |
558 | struct virtproc_info *vrp = vch->vrp; |
559 | struct device *dev = &rpdev->dev; |
560 | struct scatterlist sg; |
561 | struct rpmsg_hdr *msg; |
562 | int err; |
563 | |
564 | /* bcasting isn't allowed */ |
565 | if (src == RPMSG_ADDR_ANY || dst == RPMSG_ADDR_ANY) { |
566 | dev_err(dev, "invalid addr (src 0x%x, dst 0x%x)\n" , src, dst); |
567 | return -EINVAL; |
568 | } |
569 | |
570 | /* |
571 | * We currently use fixed-sized buffers, and therefore the payload |
572 | * length is limited. |
573 | * |
574 | * One of the possible improvements here is either to support |
575 | * user-provided buffers (and then we can also support zero-copy |
576 | * messaging), or to improve the buffer allocator, to support |
577 | * variable-length buffer sizes. |
578 | */ |
579 | if (len > vrp->buf_size - sizeof(struct rpmsg_hdr)) { |
580 | dev_err(dev, "message is too big (%d)\n" , len); |
581 | return -EMSGSIZE; |
582 | } |
583 | |
584 | /* grab a buffer */ |
585 | msg = get_a_tx_buf(vrp); |
586 | if (!msg && !wait) |
587 | return -ENOMEM; |
588 | |
589 | /* no free buffer ? wait for one (but bail after 15 seconds) */ |
590 | while (!msg) { |
591 | /* enable "tx-complete" interrupts, if not already enabled */ |
592 | rpmsg_upref_sleepers(vrp); |
593 | |
594 | /* |
595 | * sleep until a free buffer is available or 15 secs elapse. |
596 | * the timeout period is not configurable because there's |
597 | * little point in asking drivers to specify that. |
598 | * if later this happens to be required, it'd be easy to add. |
599 | */ |
600 | err = wait_event_interruptible_timeout(vrp->sendq, |
601 | (msg = get_a_tx_buf(vrp)), |
602 | msecs_to_jiffies(15000)); |
603 | |
604 | /* disable "tx-complete" interrupts if we're the last sleeper */ |
605 | rpmsg_downref_sleepers(vrp); |
606 | |
607 | /* timeout ? */ |
608 | if (!err) { |
609 | dev_err(dev, "timeout waiting for a tx buffer\n" ); |
610 | return -ERESTARTSYS; |
611 | } |
612 | } |
613 | |
614 | msg->len = cpu_to_rpmsg16(rpdev, val: len); |
615 | msg->flags = 0; |
616 | msg->src = cpu_to_rpmsg32(rpdev, val: src); |
617 | msg->dst = cpu_to_rpmsg32(rpdev, val: dst); |
618 | msg->reserved = 0; |
619 | memcpy(msg->data, data, len); |
620 | |
621 | dev_dbg(dev, "TX From 0x%x, To 0x%x, Len %d, Flags %d, Reserved %d\n" , |
622 | src, dst, len, msg->flags, msg->reserved); |
623 | #if defined(CONFIG_DYNAMIC_DEBUG) |
624 | dynamic_hex_dump("rpmsg_virtio TX: " , DUMP_PREFIX_NONE, 16, 1, |
625 | msg, sizeof(*msg) + len, true); |
626 | #endif |
627 | |
628 | rpmsg_sg_init(sg: &sg, cpu_addr: msg, len: sizeof(*msg) + len); |
629 | |
630 | mutex_lock(&vrp->tx_lock); |
631 | |
632 | /* add message to the remote processor's virtqueue */ |
633 | err = virtqueue_add_outbuf(vq: vrp->svq, sg: &sg, num: 1, data: msg, GFP_KERNEL); |
634 | if (err) { |
635 | /* |
636 | * need to reclaim the buffer here, otherwise it's lost |
637 | * (memory won't leak, but rpmsg won't use it again for TX). |
638 | * this will wait for a buffer management overhaul. |
639 | */ |
640 | dev_err(dev, "virtqueue_add_outbuf failed: %d\n" , err); |
641 | goto out; |
642 | } |
643 | |
644 | /* tell the remote processor it has a pending message to read */ |
645 | virtqueue_kick(vq: vrp->svq); |
646 | out: |
647 | mutex_unlock(lock: &vrp->tx_lock); |
648 | return err; |
649 | } |
650 | |
651 | static int virtio_rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len) |
652 | { |
653 | struct rpmsg_device *rpdev = ept->rpdev; |
654 | u32 src = ept->addr, dst = rpdev->dst; |
655 | |
656 | return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, wait: true); |
657 | } |
658 | |
659 | static int virtio_rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len, |
660 | u32 dst) |
661 | { |
662 | struct rpmsg_device *rpdev = ept->rpdev; |
663 | u32 src = ept->addr; |
664 | |
665 | return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, wait: true); |
666 | } |
667 | |
668 | static int virtio_rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src, |
669 | u32 dst, void *data, int len) |
670 | { |
671 | struct rpmsg_device *rpdev = ept->rpdev; |
672 | |
673 | return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, wait: true); |
674 | } |
675 | |
676 | static int virtio_rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len) |
677 | { |
678 | struct rpmsg_device *rpdev = ept->rpdev; |
679 | u32 src = ept->addr, dst = rpdev->dst; |
680 | |
681 | return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, wait: false); |
682 | } |
683 | |
684 | static int virtio_rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data, |
685 | int len, u32 dst) |
686 | { |
687 | struct rpmsg_device *rpdev = ept->rpdev; |
688 | u32 src = ept->addr; |
689 | |
690 | return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, wait: false); |
691 | } |
692 | |
693 | static int virtio_rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, |
694 | u32 dst, void *data, int len) |
695 | { |
696 | struct rpmsg_device *rpdev = ept->rpdev; |
697 | |
698 | return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, wait: false); |
699 | } |
700 | |
701 | static ssize_t virtio_rpmsg_get_mtu(struct rpmsg_endpoint *ept) |
702 | { |
703 | struct rpmsg_device *rpdev = ept->rpdev; |
704 | struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev); |
705 | |
706 | return vch->vrp->buf_size - sizeof(struct rpmsg_hdr); |
707 | } |
708 | |
709 | static int rpmsg_recv_single(struct virtproc_info *vrp, struct device *dev, |
710 | struct rpmsg_hdr *msg, unsigned int len) |
711 | { |
712 | struct rpmsg_endpoint *ept; |
713 | struct scatterlist sg; |
714 | bool little_endian = virtio_is_little_endian(vdev: vrp->vdev); |
715 | unsigned int msg_len = __rpmsg16_to_cpu(little_endian, val: msg->len); |
716 | int err; |
717 | |
718 | dev_dbg(dev, "From: 0x%x, To: 0x%x, Len: %d, Flags: %d, Reserved: %d\n" , |
719 | __rpmsg32_to_cpu(little_endian, msg->src), |
720 | __rpmsg32_to_cpu(little_endian, msg->dst), msg_len, |
721 | __rpmsg16_to_cpu(little_endian, msg->flags), |
722 | __rpmsg32_to_cpu(little_endian, msg->reserved)); |
723 | #if defined(CONFIG_DYNAMIC_DEBUG) |
724 | dynamic_hex_dump("rpmsg_virtio RX: " , DUMP_PREFIX_NONE, 16, 1, |
725 | msg, sizeof(*msg) + msg_len, true); |
726 | #endif |
727 | |
728 | /* |
729 | * We currently use fixed-sized buffers, so trivially sanitize |
730 | * the reported payload length. |
731 | */ |
732 | if (len > vrp->buf_size || |
733 | msg_len > (len - sizeof(struct rpmsg_hdr))) { |
734 | dev_warn(dev, "inbound msg too big: (%d, %d)\n" , len, msg_len); |
735 | return -EINVAL; |
736 | } |
737 | |
738 | /* use the dst addr to fetch the callback of the appropriate user */ |
739 | mutex_lock(&vrp->endpoints_lock); |
740 | |
741 | ept = idr_find(&vrp->endpoints, id: __rpmsg32_to_cpu(little_endian, val: msg->dst)); |
742 | |
743 | /* let's make sure no one deallocates ept while we use it */ |
744 | if (ept) |
745 | kref_get(kref: &ept->refcount); |
746 | |
747 | mutex_unlock(lock: &vrp->endpoints_lock); |
748 | |
749 | if (ept) { |
750 | /* make sure ept->cb doesn't go away while we use it */ |
751 | mutex_lock(&ept->cb_lock); |
752 | |
753 | if (ept->cb) |
754 | ept->cb(ept->rpdev, msg->data, msg_len, ept->priv, |
755 | __rpmsg32_to_cpu(little_endian, val: msg->src)); |
756 | |
757 | mutex_unlock(lock: &ept->cb_lock); |
758 | |
759 | /* farewell, ept, we don't need you anymore */ |
760 | kref_put(kref: &ept->refcount, release: __ept_release); |
761 | } else |
762 | dev_warn_ratelimited(dev, "msg received with no recipient\n" ); |
763 | |
764 | /* publish the real size of the buffer */ |
765 | rpmsg_sg_init(sg: &sg, cpu_addr: msg, len: vrp->buf_size); |
766 | |
767 | /* add the buffer back to the remote processor's virtqueue */ |
768 | err = virtqueue_add_inbuf(vq: vrp->rvq, sg: &sg, num: 1, data: msg, GFP_KERNEL); |
769 | if (err < 0) { |
770 | dev_err(dev, "failed to add a virtqueue buffer: %d\n" , err); |
771 | return err; |
772 | } |
773 | |
774 | return 0; |
775 | } |
776 | |
777 | /* called when an rx buffer is used, and it's time to digest a message */ |
778 | static void rpmsg_recv_done(struct virtqueue *rvq) |
779 | { |
780 | struct virtproc_info *vrp = rvq->vdev->priv; |
781 | struct device *dev = &rvq->vdev->dev; |
782 | struct rpmsg_hdr *msg; |
783 | unsigned int len, msgs_received = 0; |
784 | int err; |
785 | |
786 | msg = virtqueue_get_buf(vq: rvq, len: &len); |
787 | if (!msg) { |
788 | dev_err(dev, "uhm, incoming signal, but no used buffer ?\n" ); |
789 | return; |
790 | } |
791 | |
792 | while (msg) { |
793 | err = rpmsg_recv_single(vrp, dev, msg, len); |
794 | if (err) |
795 | break; |
796 | |
797 | msgs_received++; |
798 | |
799 | msg = virtqueue_get_buf(vq: rvq, len: &len); |
800 | } |
801 | |
802 | dev_dbg(dev, "Received %u messages\n" , msgs_received); |
803 | |
804 | /* tell the remote processor we added another available rx buffer */ |
805 | if (msgs_received) |
806 | virtqueue_kick(vq: vrp->rvq); |
807 | } |
808 | |
809 | /* |
810 | * This is invoked whenever the remote processor completed processing |
811 | * a TX msg we just sent it, and the buffer is put back to the used ring. |
812 | * |
813 | * Normally, though, we suppress this "tx complete" interrupt in order to |
814 | * avoid the incurred overhead. |
815 | */ |
816 | static void rpmsg_xmit_done(struct virtqueue *svq) |
817 | { |
818 | struct virtproc_info *vrp = svq->vdev->priv; |
819 | |
820 | dev_dbg(&svq->vdev->dev, "%s\n" , __func__); |
821 | |
822 | /* wake up potential senders that are waiting for a tx buffer */ |
823 | wake_up_interruptible(&vrp->sendq); |
824 | } |
825 | |
826 | /* |
827 | * Called to expose to user a /dev/rpmsg_ctrlX interface allowing to |
828 | * create endpoint-to-endpoint communication without associated RPMsg channel. |
829 | * The endpoints are rattached to the ctrldev RPMsg device. |
830 | */ |
831 | static struct rpmsg_device *rpmsg_virtio_add_ctrl_dev(struct virtio_device *vdev) |
832 | { |
833 | struct virtproc_info *vrp = vdev->priv; |
834 | struct virtio_rpmsg_channel *vch; |
835 | struct rpmsg_device *rpdev_ctrl; |
836 | int err = 0; |
837 | |
838 | vch = kzalloc(size: sizeof(*vch), GFP_KERNEL); |
839 | if (!vch) |
840 | return ERR_PTR(error: -ENOMEM); |
841 | |
842 | /* Link the channel to the vrp */ |
843 | vch->vrp = vrp; |
844 | |
845 | /* Assign public information to the rpmsg_device */ |
846 | rpdev_ctrl = &vch->rpdev; |
847 | rpdev_ctrl->ops = &virtio_rpmsg_ops; |
848 | |
849 | rpdev_ctrl->dev.parent = &vrp->vdev->dev; |
850 | rpdev_ctrl->dev.release = virtio_rpmsg_release_device; |
851 | rpdev_ctrl->little_endian = virtio_is_little_endian(vdev: vrp->vdev); |
852 | |
853 | err = rpmsg_ctrldev_register_device(rpdev: rpdev_ctrl); |
854 | if (err) { |
855 | /* vch will be free in virtio_rpmsg_release_device() */ |
856 | return ERR_PTR(error: err); |
857 | } |
858 | |
859 | return rpdev_ctrl; |
860 | } |
861 | |
862 | static void rpmsg_virtio_del_ctrl_dev(struct rpmsg_device *rpdev_ctrl) |
863 | { |
864 | if (!rpdev_ctrl) |
865 | return; |
866 | device_unregister(dev: &rpdev_ctrl->dev); |
867 | } |
868 | |
869 | static int rpmsg_probe(struct virtio_device *vdev) |
870 | { |
871 | vq_callback_t *vq_cbs[] = { rpmsg_recv_done, rpmsg_xmit_done }; |
872 | static const char * const names[] = { "input" , "output" }; |
873 | struct virtqueue *vqs[2]; |
874 | struct virtproc_info *vrp; |
875 | struct virtio_rpmsg_channel *vch = NULL; |
876 | struct rpmsg_device *rpdev_ns, *rpdev_ctrl; |
877 | void *bufs_va; |
878 | int err = 0, i; |
879 | size_t total_buf_space; |
880 | bool notify; |
881 | |
882 | vrp = kzalloc(size: sizeof(*vrp), GFP_KERNEL); |
883 | if (!vrp) |
884 | return -ENOMEM; |
885 | |
886 | vrp->vdev = vdev; |
887 | |
888 | idr_init(idr: &vrp->endpoints); |
889 | mutex_init(&vrp->endpoints_lock); |
890 | mutex_init(&vrp->tx_lock); |
891 | init_waitqueue_head(&vrp->sendq); |
892 | |
893 | /* We expect two virtqueues, rx and tx (and in this order) */ |
894 | err = virtio_find_vqs(vdev, nvqs: 2, vqs, callbacks: vq_cbs, names, NULL); |
895 | if (err) |
896 | goto free_vrp; |
897 | |
898 | vrp->rvq = vqs[0]; |
899 | vrp->svq = vqs[1]; |
900 | |
901 | /* we expect symmetric tx/rx vrings */ |
902 | WARN_ON(virtqueue_get_vring_size(vrp->rvq) != |
903 | virtqueue_get_vring_size(vrp->svq)); |
904 | |
905 | /* we need less buffers if vrings are small */ |
906 | if (virtqueue_get_vring_size(vq: vrp->rvq) < MAX_RPMSG_NUM_BUFS / 2) |
907 | vrp->num_bufs = virtqueue_get_vring_size(vq: vrp->rvq) * 2; |
908 | else |
909 | vrp->num_bufs = MAX_RPMSG_NUM_BUFS; |
910 | |
911 | vrp->buf_size = MAX_RPMSG_BUF_SIZE; |
912 | |
913 | total_buf_space = vrp->num_bufs * vrp->buf_size; |
914 | |
915 | /* allocate coherent memory for the buffers */ |
916 | bufs_va = dma_alloc_coherent(dev: vdev->dev.parent, |
917 | size: total_buf_space, dma_handle: &vrp->bufs_dma, |
918 | GFP_KERNEL); |
919 | if (!bufs_va) { |
920 | err = -ENOMEM; |
921 | goto vqs_del; |
922 | } |
923 | |
924 | dev_dbg(&vdev->dev, "buffers: va %pK, dma %pad\n" , |
925 | bufs_va, &vrp->bufs_dma); |
926 | |
927 | /* half of the buffers is dedicated for RX */ |
928 | vrp->rbufs = bufs_va; |
929 | |
930 | /* and half is dedicated for TX */ |
931 | vrp->sbufs = bufs_va + total_buf_space / 2; |
932 | |
933 | /* set up the receive buffers */ |
934 | for (i = 0; i < vrp->num_bufs / 2; i++) { |
935 | struct scatterlist sg; |
936 | void *cpu_addr = vrp->rbufs + i * vrp->buf_size; |
937 | |
938 | rpmsg_sg_init(sg: &sg, cpu_addr, len: vrp->buf_size); |
939 | |
940 | err = virtqueue_add_inbuf(vq: vrp->rvq, sg: &sg, num: 1, data: cpu_addr, |
941 | GFP_KERNEL); |
942 | WARN_ON(err); /* sanity check; this can't really happen */ |
943 | } |
944 | |
945 | /* suppress "tx-complete" interrupts */ |
946 | virtqueue_disable_cb(vq: vrp->svq); |
947 | |
948 | vdev->priv = vrp; |
949 | |
950 | rpdev_ctrl = rpmsg_virtio_add_ctrl_dev(vdev); |
951 | if (IS_ERR(ptr: rpdev_ctrl)) { |
952 | err = PTR_ERR(ptr: rpdev_ctrl); |
953 | goto free_coherent; |
954 | } |
955 | |
956 | /* if supported by the remote processor, enable the name service */ |
957 | if (virtio_has_feature(vdev, VIRTIO_RPMSG_F_NS)) { |
958 | vch = kzalloc(size: sizeof(*vch), GFP_KERNEL); |
959 | if (!vch) { |
960 | err = -ENOMEM; |
961 | goto free_ctrldev; |
962 | } |
963 | |
964 | /* Link the channel to our vrp */ |
965 | vch->vrp = vrp; |
966 | |
967 | /* Assign public information to the rpmsg_device */ |
968 | rpdev_ns = &vch->rpdev; |
969 | rpdev_ns->ops = &virtio_rpmsg_ops; |
970 | rpdev_ns->little_endian = virtio_is_little_endian(vdev: vrp->vdev); |
971 | |
972 | rpdev_ns->dev.parent = &vrp->vdev->dev; |
973 | rpdev_ns->dev.release = virtio_rpmsg_release_device; |
974 | |
975 | err = rpmsg_ns_register_device(rpdev: rpdev_ns); |
976 | if (err) |
977 | /* vch will be free in virtio_rpmsg_release_device() */ |
978 | goto free_ctrldev; |
979 | } |
980 | |
981 | /* |
982 | * Prepare to kick but don't notify yet - we can't do this before |
983 | * device is ready. |
984 | */ |
985 | notify = virtqueue_kick_prepare(vq: vrp->rvq); |
986 | |
987 | /* From this point on, we can notify and get callbacks. */ |
988 | virtio_device_ready(dev: vdev); |
989 | |
990 | /* tell the remote processor it can start sending messages */ |
991 | /* |
992 | * this might be concurrent with callbacks, but we are only |
993 | * doing notify, not a full kick here, so that's ok. |
994 | */ |
995 | if (notify) |
996 | virtqueue_notify(vq: vrp->rvq); |
997 | |
998 | dev_info(&vdev->dev, "rpmsg host is online\n" ); |
999 | |
1000 | return 0; |
1001 | |
1002 | free_ctrldev: |
1003 | rpmsg_virtio_del_ctrl_dev(rpdev_ctrl); |
1004 | free_coherent: |
1005 | dma_free_coherent(dev: vdev->dev.parent, size: total_buf_space, |
1006 | cpu_addr: bufs_va, dma_handle: vrp->bufs_dma); |
1007 | vqs_del: |
1008 | vdev->config->del_vqs(vrp->vdev); |
1009 | free_vrp: |
1010 | kfree(objp: vrp); |
1011 | return err; |
1012 | } |
1013 | |
1014 | static int rpmsg_remove_device(struct device *dev, void *data) |
1015 | { |
1016 | device_unregister(dev); |
1017 | |
1018 | return 0; |
1019 | } |
1020 | |
1021 | static void rpmsg_remove(struct virtio_device *vdev) |
1022 | { |
1023 | struct virtproc_info *vrp = vdev->priv; |
1024 | size_t total_buf_space = vrp->num_bufs * vrp->buf_size; |
1025 | int ret; |
1026 | |
1027 | virtio_reset_device(dev: vdev); |
1028 | |
1029 | ret = device_for_each_child(dev: &vdev->dev, NULL, fn: rpmsg_remove_device); |
1030 | if (ret) |
1031 | dev_warn(&vdev->dev, "can't remove rpmsg device: %d\n" , ret); |
1032 | |
1033 | idr_destroy(&vrp->endpoints); |
1034 | |
1035 | vdev->config->del_vqs(vrp->vdev); |
1036 | |
1037 | dma_free_coherent(dev: vdev->dev.parent, size: total_buf_space, |
1038 | cpu_addr: vrp->rbufs, dma_handle: vrp->bufs_dma); |
1039 | |
1040 | kfree(objp: vrp); |
1041 | } |
1042 | |
1043 | static struct virtio_device_id id_table[] = { |
1044 | { VIRTIO_ID_RPMSG, VIRTIO_DEV_ANY_ID }, |
1045 | { 0 }, |
1046 | }; |
1047 | |
1048 | static unsigned int features[] = { |
1049 | VIRTIO_RPMSG_F_NS, |
1050 | }; |
1051 | |
1052 | static struct virtio_driver virtio_ipc_driver = { |
1053 | .feature_table = features, |
1054 | .feature_table_size = ARRAY_SIZE(features), |
1055 | .driver.name = KBUILD_MODNAME, |
1056 | .driver.owner = THIS_MODULE, |
1057 | .id_table = id_table, |
1058 | .probe = rpmsg_probe, |
1059 | .remove = rpmsg_remove, |
1060 | }; |
1061 | |
1062 | static int __init rpmsg_init(void) |
1063 | { |
1064 | int ret; |
1065 | |
1066 | ret = register_virtio_driver(&virtio_ipc_driver); |
1067 | if (ret) |
1068 | pr_err("failed to register virtio driver: %d\n" , ret); |
1069 | |
1070 | return ret; |
1071 | } |
1072 | subsys_initcall(rpmsg_init); |
1073 | |
1074 | static void __exit rpmsg_fini(void) |
1075 | { |
1076 | unregister_virtio_driver(drv: &virtio_ipc_driver); |
1077 | } |
1078 | module_exit(rpmsg_fini); |
1079 | |
1080 | MODULE_DEVICE_TABLE(virtio, id_table); |
1081 | MODULE_DESCRIPTION("Virtio-based remote processor messaging bus" ); |
1082 | MODULE_LICENSE("GPL v2" ); |
1083 | |