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1 | /* |
2 | * Virtio-based remote processor messaging bus |
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 | #define pr_fmt(fmt) "%s: " fmt, __func__ |
21 | |
22 | #include <linux/kernel.h> |
23 | #include <linux/module.h> |
24 | #include <linux/virtio.h> |
25 | #include <linux/virtio_ids.h> |
26 | #include <linux/virtio_config.h> |
27 | #include <linux/scatterlist.h> |
28 | #include <linux/dma-mapping.h> |
29 | #include <linux/slab.h> |
30 | #include <linux/idr.h> |
31 | #include <linux/jiffies.h> |
32 | #include <linux/sched.h> |
33 | #include <linux/wait.h> |
34 | #include <linux/rpmsg.h> |
35 | #include <linux/mutex.h> |
36 | |
37 | /** |
38 | * struct virtproc_info - virtual remote processor state |
39 | * @vdev: the virtio device |
40 | * @rvq: rx virtqueue |
41 | * @svq: tx virtqueue |
42 | * @rbufs: kernel address of rx buffers |
43 | * @sbufs: kernel address of tx buffers |
44 | * @last_sbuf: index of last tx buffer used |
45 | * @bufs_dma: dma base addr of the buffers |
46 | * @tx_lock: protects svq, sbufs and sleepers, to allow concurrent senders. |
47 | * sending a message might require waking up a dozing remote |
48 | * processor, which involves sleeping, hence the mutex. |
49 | * @endpoints: idr of local endpoints, allows fast retrieval |
50 | * @endpoints_lock: lock of the endpoints set |
51 | * @sendq: wait queue of sending contexts waiting for a tx buffers |
52 | * @sleepers: number of senders that are waiting for a tx buffer |
53 | * @ns_ept: the bus's name service endpoint |
54 | * |
55 | * This structure stores the rpmsg state of a given virtio remote processor |
56 | * device (there might be several virtio proc devices for each physical |
57 | * remote processor). |
58 | */ |
59 | struct virtproc_info { |
60 | struct virtio_device *vdev; |
61 | struct virtqueue *rvq, *svq; |
62 | void *rbufs, *sbufs; |
63 | int last_sbuf; |
64 | dma_addr_t bufs_dma; |
65 | struct mutex tx_lock; |
66 | struct idr endpoints; |
67 | struct mutex endpoints_lock; |
68 | wait_queue_head_t sendq; |
69 | atomic_t sleepers; |
70 | struct rpmsg_endpoint *ns_ept; |
71 | }; |
72 | |
73 | /** |
74 | * struct rpmsg_channel_info - internal channel info representation |
75 | * @name: name of service |
76 | * @src: local address |
77 | * @dst: destination address |
78 | */ |
79 | struct rpmsg_channel_info { |
80 | char name[RPMSG_NAME_SIZE]; |
81 | u32 src; |
82 | u32 dst; |
83 | }; |
84 | |
85 | #define to_rpmsg_channel(d) container_of(d, struct rpmsg_channel, dev) |
86 | #define to_rpmsg_driver(d) container_of(d, struct rpmsg_driver, drv) |
87 | |
88 | /* |
89 | * We're allocating 512 buffers of 512 bytes for communications, and then |
90 | * using the first 256 buffers for RX, and the last 256 buffers for TX. |
91 | * |
92 | * Each buffer will have 16 bytes for the msg header and 496 bytes for |
93 | * the payload. |
94 | * |
95 | * This will require a total space of 256KB for the buffers. |
96 | * |
97 | * We might also want to add support for user-provided buffers in time. |
98 | * This will allow bigger buffer size flexibility, and can also be used |
99 | * to achieve zero-copy messaging. |
100 | * |
101 | * Note that these numbers are purely a decision of this driver - we |
102 | * can change this without changing anything in the firmware of the remote |
103 | * processor. |
104 | */ |
105 | #define RPMSG_NUM_BUFS (512) |
106 | #define RPMSG_BUF_SIZE (512) |
107 | #define RPMSG_TOTAL_BUF_SPACE (RPMSG_NUM_BUFS * RPMSG_BUF_SIZE) |
108 | |
109 | /* |
110 | * Local addresses are dynamically allocated on-demand. |
111 | * We do not dynamically assign addresses from the low 1024 range, |
112 | * in order to reserve that address range for predefined services. |
113 | */ |
114 | #define RPMSG_RESERVED_ADDRESSES (1024) |
115 | |
116 | /* Address 53 is reserved for advertising remote services */ |
117 | #define RPMSG_NS_ADDR (53) |
118 | |
119 | /* sysfs show configuration fields */ |
120 | #define rpmsg_show_attr(field, path, format_string) \ |
121 | static ssize_t \ |
122 | field##_show(struct device *dev, \ |
123 | struct device_attribute *attr, char *buf) \ |
124 | { \ |
125 | struct rpmsg_channel *rpdev = to_rpmsg_channel(dev); \ |
126 | \ |
127 | return sprintf(buf, format_string, rpdev->path); \ |
128 | } |
129 | |
130 | /* for more info, see Documentation/ABI/testing/sysfs-bus-rpmsg */ |
131 | rpmsg_show_attr(name, id.name, "%s\n"); |
132 | rpmsg_show_attr(src, src, "0x%x\n"); |
133 | rpmsg_show_attr(dst, dst, "0x%x\n"); |
134 | rpmsg_show_attr(announce, announce ? "true" : "false", "%s\n"); |
135 | |
136 | /* |
137 | * Unique (and free running) index for rpmsg devices. |
138 | * |
139 | * Yeah, we're not recycling those numbers (yet?). will be easy |
140 | * to change if/when we want to. |
141 | */ |
142 | static unsigned int rpmsg_dev_index; |
143 | |
144 | static ssize_t modalias_show(struct device *dev, |
145 | struct device_attribute *attr, char *buf) |
146 | { |
147 | struct rpmsg_channel *rpdev = to_rpmsg_channel(dev); |
148 | |
149 | return sprintf(buf, RPMSG_DEVICE_MODALIAS_FMT "\n", rpdev->id.name); |
150 | } |
151 | |
152 | static struct device_attribute rpmsg_dev_attrs[] = { |
153 | __ATTR_RO(name), |
154 | __ATTR_RO(modalias), |
155 | __ATTR_RO(dst), |
156 | __ATTR_RO(src), |
157 | __ATTR_RO(announce), |
158 | __ATTR_NULL |
159 | }; |
160 | |
161 | /* rpmsg devices and drivers are matched using the service name */ |
162 | static inline int rpmsg_id_match(const struct rpmsg_channel *rpdev, |
163 | const struct rpmsg_device_id *id) |
164 | { |
165 | return strncmp(id->name, rpdev->id.name, RPMSG_NAME_SIZE) == 0; |
166 | } |
167 | |
168 | /* match rpmsg channel and rpmsg driver */ |
169 | static int rpmsg_dev_match(struct device *dev, struct device_driver *drv) |
170 | { |
171 | struct rpmsg_channel *rpdev = to_rpmsg_channel(dev); |
172 | struct rpmsg_driver *rpdrv = to_rpmsg_driver(drv); |
173 | const struct rpmsg_device_id *ids = rpdrv->id_table; |
174 | unsigned int i; |
175 | |
176 | for (i = 0; ids[i].name[0]; i++) |
177 | if (rpmsg_id_match(rpdev, &ids[i])) |
178 | return 1; |
179 | |
180 | return 0; |
181 | } |
182 | |
183 | static int rpmsg_uevent(struct device *dev, struct kobj_uevent_env *env) |
184 | { |
185 | struct rpmsg_channel *rpdev = to_rpmsg_channel(dev); |
186 | |
187 | return add_uevent_var(env, "MODALIAS=" RPMSG_DEVICE_MODALIAS_FMT, |
188 | rpdev->id.name); |
189 | } |
190 | |
191 | /* for more info, see below documentation of rpmsg_create_ept() */ |
192 | static struct rpmsg_endpoint *__rpmsg_create_ept(struct virtproc_info *vrp, |
193 | struct rpmsg_channel *rpdev, rpmsg_rx_cb_t cb, |
194 | void *priv, u32 addr) |
195 | { |
196 | int err, tmpaddr, request; |
197 | struct rpmsg_endpoint *ept; |
198 | struct device *dev = rpdev ? &rpdev->dev : &vrp->vdev->dev; |
199 | |
200 | if (!idr_pre_get(&vrp->endpoints, GFP_KERNEL)) |
201 | return NULL; |
202 | |
203 | ept = kzalloc(sizeof(*ept), GFP_KERNEL); |
204 | if (!ept) { |
205 | dev_err(dev, "failed to kzalloc a new ept\n"); |
206 | return NULL; |
207 | } |
208 | |
209 | ept->rpdev = rpdev; |
210 | ept->cb = cb; |
211 | ept->priv = priv; |
212 | |
213 | /* do we need to allocate a local address ? */ |
214 | request = addr == RPMSG_ADDR_ANY ? RPMSG_RESERVED_ADDRESSES : addr; |
215 | |
216 | mutex_lock(&vrp->endpoints_lock); |
217 | |
218 | /* bind the endpoint to an rpmsg address (and allocate one if needed) */ |
219 | err = idr_get_new_above(&vrp->endpoints, ept, request, &tmpaddr); |
220 | if (err) { |
221 | dev_err(dev, "idr_get_new_above failed: %d\n", err); |
222 | goto free_ept; |
223 | } |
224 | |
225 | /* make sure the user's address request is fulfilled, if relevant */ |
226 | if (addr != RPMSG_ADDR_ANY && tmpaddr != addr) { |
227 | dev_err(dev, "address 0x%x already in use\n", addr); |
228 | goto rem_idr; |
229 | } |
230 | |
231 | ept->addr = tmpaddr; |
232 | |
233 | mutex_unlock(&vrp->endpoints_lock); |
234 | |
235 | return ept; |
236 | |
237 | rem_idr: |
238 | idr_remove(&vrp->endpoints, request); |
239 | free_ept: |
240 | mutex_unlock(&vrp->endpoints_lock); |
241 | kfree(ept); |
242 | return NULL; |
243 | } |
244 | |
245 | /** |
246 | * rpmsg_create_ept() - create a new rpmsg_endpoint |
247 | * @rpdev: rpmsg channel device |
248 | * @cb: rx callback handler |
249 | * @priv: private data for the driver's use |
250 | * @addr: local rpmsg address to bind with @cb |
251 | * |
252 | * Every rpmsg address in the system is bound to an rx callback (so when |
253 | * inbound messages arrive, they are dispatched by the rpmsg bus using the |
254 | * appropriate callback handler) by means of an rpmsg_endpoint struct. |
255 | * |
256 | * This function allows drivers to create such an endpoint, and by that, |
257 | * bind a callback, and possibly some private data too, to an rpmsg address |
258 | * (either one that is known in advance, or one that will be dynamically |
259 | * assigned for them). |
260 | * |
261 | * Simple rpmsg drivers need not call rpmsg_create_ept, because an endpoint |
262 | * is already created for them when they are probed by the rpmsg bus |
263 | * (using the rx callback provided when they registered to the rpmsg bus). |
264 | * |
265 | * So things should just work for simple drivers: they already have an |
266 | * endpoint, their rx callback is bound to their rpmsg address, and when |
267 | * relevant inbound messages arrive (i.e. messages which their dst address |
268 | * equals to the src address of their rpmsg channel), the driver's handler |
269 | * is invoked to process it. |
270 | * |
271 | * That said, more complicated drivers might do need to allocate |
272 | * additional rpmsg addresses, and bind them to different rx callbacks. |
273 | * To accomplish that, those drivers need to call this function. |
274 | * |
275 | * Drivers should provide their @rpdev channel (so the new endpoint would belong |
276 | * to the same remote processor their channel belongs to), an rx callback |
277 | * function, an optional private data (which is provided back when the |
278 | * rx callback is invoked), and an address they want to bind with the |
279 | * callback. If @addr is RPMSG_ADDR_ANY, then rpmsg_create_ept will |
280 | * dynamically assign them an available rpmsg address (drivers should have |
281 | * a very good reason why not to always use RPMSG_ADDR_ANY here). |
282 | * |
283 | * Returns a pointer to the endpoint on success, or NULL on error. |
284 | */ |
285 | struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_channel *rpdev, |
286 | rpmsg_rx_cb_t cb, void *priv, u32 addr) |
287 | { |
288 | return __rpmsg_create_ept(rpdev->vrp, rpdev, cb, priv, addr); |
289 | } |
290 | EXPORT_SYMBOL(rpmsg_create_ept); |
291 | |
292 | /** |
293 | * __rpmsg_destroy_ept() - destroy an existing rpmsg endpoint |
294 | * @vrp: virtproc which owns this ept |
295 | * @ept: endpoing to destroy |
296 | * |
297 | * An internal function which destroy an ept without assuming it is |
298 | * bound to an rpmsg channel. This is needed for handling the internal |
299 | * name service endpoint, which isn't bound to an rpmsg channel. |
300 | * See also __rpmsg_create_ept(). |
301 | */ |
302 | static void |
303 | __rpmsg_destroy_ept(struct virtproc_info *vrp, struct rpmsg_endpoint *ept) |
304 | { |
305 | mutex_lock(&vrp->endpoints_lock); |
306 | idr_remove(&vrp->endpoints, ept->addr); |
307 | mutex_unlock(&vrp->endpoints_lock); |
308 | |
309 | kfree(ept); |
310 | } |
311 | |
312 | /** |
313 | * rpmsg_destroy_ept() - destroy an existing rpmsg endpoint |
314 | * @ept: endpoing to destroy |
315 | * |
316 | * Should be used by drivers to destroy an rpmsg endpoint previously |
317 | * created with rpmsg_create_ept(). |
318 | */ |
319 | void rpmsg_destroy_ept(struct rpmsg_endpoint *ept) |
320 | { |
321 | __rpmsg_destroy_ept(ept->rpdev->vrp, ept); |
322 | } |
323 | EXPORT_SYMBOL(rpmsg_destroy_ept); |
324 | |
325 | /* |
326 | * when an rpmsg driver is probed with a channel, we seamlessly create |
327 | * it an endpoint, binding its rx callback to a unique local rpmsg |
328 | * address. |
329 | * |
330 | * if we need to, we also announce about this channel to the remote |
331 | * processor (needed in case the driver is exposing an rpmsg service). |
332 | */ |
333 | static int rpmsg_dev_probe(struct device *dev) |
334 | { |
335 | struct rpmsg_channel *rpdev = to_rpmsg_channel(dev); |
336 | struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver); |
337 | struct virtproc_info *vrp = rpdev->vrp; |
338 | struct rpmsg_endpoint *ept; |
339 | int err; |
340 | |
341 | ept = rpmsg_create_ept(rpdev, rpdrv->callback, NULL, rpdev->src); |
342 | if (!ept) { |
343 | dev_err(dev, "failed to create endpoint\n"); |
344 | err = -ENOMEM; |
345 | goto out; |
346 | } |
347 | |
348 | rpdev->ept = ept; |
349 | rpdev->src = ept->addr; |
350 | |
351 | err = rpdrv->probe(rpdev); |
352 | if (err) { |
353 | dev_err(dev, "%s: failed: %d\n", __func__, err); |
354 | rpmsg_destroy_ept(ept); |
355 | goto out; |
356 | } |
357 | |
358 | /* need to tell remote processor's name service about this channel ? */ |
359 | if (rpdev->announce && |
360 | virtio_has_feature(vrp->vdev, VIRTIO_RPMSG_F_NS)) { |
361 | struct rpmsg_ns_msg nsm; |
362 | |
363 | strncpy(nsm.name, rpdev->id.name, RPMSG_NAME_SIZE); |
364 | nsm.addr = rpdev->src; |
365 | nsm.flags = RPMSG_NS_CREATE; |
366 | |
367 | err = rpmsg_sendto(rpdev, &nsm, sizeof(nsm), RPMSG_NS_ADDR); |
368 | if (err) |
369 | dev_err(dev, "failed to announce service %d\n", err); |
370 | } |
371 | |
372 | out: |
373 | return err; |
374 | } |
375 | |
376 | static int rpmsg_dev_remove(struct device *dev) |
377 | { |
378 | struct rpmsg_channel *rpdev = to_rpmsg_channel(dev); |
379 | struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver); |
380 | struct virtproc_info *vrp = rpdev->vrp; |
381 | int err = 0; |
382 | |
383 | /* tell remote processor's name service we're removing this channel */ |
384 | if (rpdev->announce && |
385 | virtio_has_feature(vrp->vdev, VIRTIO_RPMSG_F_NS)) { |
386 | struct rpmsg_ns_msg nsm; |
387 | |
388 | strncpy(nsm.name, rpdev->id.name, RPMSG_NAME_SIZE); |
389 | nsm.addr = rpdev->src; |
390 | nsm.flags = RPMSG_NS_DESTROY; |
391 | |
392 | err = rpmsg_sendto(rpdev, &nsm, sizeof(nsm), RPMSG_NS_ADDR); |
393 | if (err) |
394 | dev_err(dev, "failed to announce service %d\n", err); |
395 | } |
396 | |
397 | rpdrv->remove(rpdev); |
398 | |
399 | rpmsg_destroy_ept(rpdev->ept); |
400 | |
401 | return err; |
402 | } |
403 | |
404 | static struct bus_type rpmsg_bus = { |
405 | .name = "rpmsg", |
406 | .match = rpmsg_dev_match, |
407 | .dev_attrs = rpmsg_dev_attrs, |
408 | .uevent = rpmsg_uevent, |
409 | .probe = rpmsg_dev_probe, |
410 | .remove = rpmsg_dev_remove, |
411 | }; |
412 | |
413 | /** |
414 | * register_rpmsg_driver() - register an rpmsg driver with the rpmsg bus |
415 | * @rpdrv: pointer to a struct rpmsg_driver |
416 | * |
417 | * Returns 0 on success, and an appropriate error value on failure. |
418 | */ |
419 | int register_rpmsg_driver(struct rpmsg_driver *rpdrv) |
420 | { |
421 | rpdrv->drv.bus = &rpmsg_bus; |
422 | return driver_register(&rpdrv->drv); |
423 | } |
424 | EXPORT_SYMBOL(register_rpmsg_driver); |
425 | |
426 | /** |
427 | * unregister_rpmsg_driver() - unregister an rpmsg driver from the rpmsg bus |
428 | * @rpdrv: pointer to a struct rpmsg_driver |
429 | * |
430 | * Returns 0 on success, and an appropriate error value on failure. |
431 | */ |
432 | void unregister_rpmsg_driver(struct rpmsg_driver *rpdrv) |
433 | { |
434 | driver_unregister(&rpdrv->drv); |
435 | } |
436 | EXPORT_SYMBOL(unregister_rpmsg_driver); |
437 | |
438 | static void rpmsg_release_device(struct device *dev) |
439 | { |
440 | struct rpmsg_channel *rpdev = to_rpmsg_channel(dev); |
441 | |
442 | kfree(rpdev); |
443 | } |
444 | |
445 | /* |
446 | * match an rpmsg channel with a channel info struct. |
447 | * this is used to make sure we're not creating rpmsg devices for channels |
448 | * that already exist. |
449 | */ |
450 | static int rpmsg_channel_match(struct device *dev, void *data) |
451 | { |
452 | struct rpmsg_channel_info *chinfo = data; |
453 | struct rpmsg_channel *rpdev = to_rpmsg_channel(dev); |
454 | |
455 | if (chinfo->src != RPMSG_ADDR_ANY && chinfo->src != rpdev->src) |
456 | return 0; |
457 | |
458 | if (chinfo->dst != RPMSG_ADDR_ANY && chinfo->dst != rpdev->dst) |
459 | return 0; |
460 | |
461 | if (strncmp(chinfo->name, rpdev->id.name, RPMSG_NAME_SIZE)) |
462 | return 0; |
463 | |
464 | /* found a match ! */ |
465 | return 1; |
466 | } |
467 | |
468 | /* |
469 | * create an rpmsg channel using its name and address info. |
470 | * this function will be used to create both static and dynamic |
471 | * channels. |
472 | */ |
473 | static struct rpmsg_channel *rpmsg_create_channel(struct virtproc_info *vrp, |
474 | struct rpmsg_channel_info *chinfo) |
475 | { |
476 | struct rpmsg_channel *rpdev; |
477 | struct device *tmp, *dev = &vrp->vdev->dev; |
478 | int ret; |
479 | |
480 | /* make sure a similar channel doesn't already exist */ |
481 | tmp = device_find_child(dev, chinfo, rpmsg_channel_match); |
482 | if (tmp) { |
483 | /* decrement the matched device's refcount back */ |
484 | put_device(tmp); |
485 | dev_err(dev, "channel %s:%x:%x already exist\n", |
486 | chinfo->name, chinfo->src, chinfo->dst); |
487 | return NULL; |
488 | } |
489 | |
490 | rpdev = kzalloc(sizeof(struct rpmsg_channel), GFP_KERNEL); |
491 | if (!rpdev) { |
492 | pr_err("kzalloc failed\n"); |
493 | return NULL; |
494 | } |
495 | |
496 | rpdev->vrp = vrp; |
497 | rpdev->src = chinfo->src; |
498 | rpdev->dst = chinfo->dst; |
499 | |
500 | /* |
501 | * rpmsg server channels has predefined local address (for now), |
502 | * and their existence needs to be announced remotely |
503 | */ |
504 | rpdev->announce = rpdev->src != RPMSG_ADDR_ANY ? true : false; |
505 | |
506 | strncpy(rpdev->id.name, chinfo->name, RPMSG_NAME_SIZE); |
507 | |
508 | /* very simple device indexing plumbing which is enough for now */ |
509 | dev_set_name(&rpdev->dev, "rpmsg%d", rpmsg_dev_index++); |
510 | |
511 | rpdev->dev.parent = &vrp->vdev->dev; |
512 | rpdev->dev.bus = &rpmsg_bus; |
513 | rpdev->dev.release = rpmsg_release_device; |
514 | |
515 | ret = device_register(&rpdev->dev); |
516 | if (ret) { |
517 | dev_err(dev, "device_register failed: %d\n", ret); |
518 | put_device(&rpdev->dev); |
519 | return NULL; |
520 | } |
521 | |
522 | return rpdev; |
523 | } |
524 | |
525 | /* |
526 | * find an existing channel using its name + address properties, |
527 | * and destroy it |
528 | */ |
529 | static int rpmsg_destroy_channel(struct virtproc_info *vrp, |
530 | struct rpmsg_channel_info *chinfo) |
531 | { |
532 | struct virtio_device *vdev = vrp->vdev; |
533 | struct device *dev; |
534 | |
535 | dev = device_find_child(&vdev->dev, chinfo, rpmsg_channel_match); |
536 | if (!dev) |
537 | return -EINVAL; |
538 | |
539 | device_unregister(dev); |
540 | |
541 | put_device(dev); |
542 | |
543 | return 0; |
544 | } |
545 | |
546 | /* super simple buffer "allocator" that is just enough for now */ |
547 | static void *get_a_tx_buf(struct virtproc_info *vrp) |
548 | { |
549 | unsigned int len; |
550 | void *ret; |
551 | |
552 | /* support multiple concurrent senders */ |
553 | mutex_lock(&vrp->tx_lock); |
554 | |
555 | /* |
556 | * either pick the next unused tx buffer |
557 | * (half of our buffers are used for sending messages) |
558 | */ |
559 | if (vrp->last_sbuf < RPMSG_NUM_BUFS / 2) |
560 | ret = vrp->sbufs + RPMSG_BUF_SIZE * vrp->last_sbuf++; |
561 | /* or recycle a used one */ |
562 | else |
563 | ret = virtqueue_get_buf(vrp->svq, &len); |
564 | |
565 | mutex_unlock(&vrp->tx_lock); |
566 | |
567 | return ret; |
568 | } |
569 | |
570 | /** |
571 | * rpmsg_upref_sleepers() - enable "tx-complete" interrupts, if needed |
572 | * @vrp: virtual remote processor state |
573 | * |
574 | * This function is called before a sender is blocked, waiting for |
575 | * a tx buffer to become available. |
576 | * |
577 | * If we already have blocking senders, this function merely increases |
578 | * the "sleepers" reference count, and exits. |
579 | * |
580 | * Otherwise, if this is the first sender to block, we also enable |
581 | * virtio's tx callbacks, so we'd be immediately notified when a tx |
582 | * buffer is consumed (we rely on virtio's tx callback in order |
583 | * to wake up sleeping senders as soon as a tx buffer is used by the |
584 | * remote processor). |
585 | */ |
586 | static void rpmsg_upref_sleepers(struct virtproc_info *vrp) |
587 | { |
588 | /* support multiple concurrent senders */ |
589 | mutex_lock(&vrp->tx_lock); |
590 | |
591 | /* are we the first sleeping context waiting for tx buffers ? */ |
592 | if (atomic_inc_return(&vrp->sleepers) == 1) |
593 | /* enable "tx-complete" interrupts before dozing off */ |
594 | virtqueue_enable_cb(vrp->svq); |
595 | |
596 | mutex_unlock(&vrp->tx_lock); |
597 | } |
598 | |
599 | /** |
600 | * rpmsg_downref_sleepers() - disable "tx-complete" interrupts, if needed |
601 | * @vrp: virtual remote processor state |
602 | * |
603 | * This function is called after a sender, that waited for a tx buffer |
604 | * to become available, is unblocked. |
605 | * |
606 | * If we still have blocking senders, this function merely decreases |
607 | * the "sleepers" reference count, and exits. |
608 | * |
609 | * Otherwise, if there are no more blocking senders, we also disable |
610 | * virtio's tx callbacks, to avoid the overhead incurred with handling |
611 | * those (now redundant) interrupts. |
612 | */ |
613 | static void rpmsg_downref_sleepers(struct virtproc_info *vrp) |
614 | { |
615 | /* support multiple concurrent senders */ |
616 | mutex_lock(&vrp->tx_lock); |
617 | |
618 | /* are we the last sleeping context waiting for tx buffers ? */ |
619 | if (atomic_dec_and_test(&vrp->sleepers)) |
620 | /* disable "tx-complete" interrupts */ |
621 | virtqueue_disable_cb(vrp->svq); |
622 | |
623 | mutex_unlock(&vrp->tx_lock); |
624 | } |
625 | |
626 | /** |
627 | * rpmsg_send_offchannel_raw() - send a message across to the remote processor |
628 | * @rpdev: the rpmsg channel |
629 | * @src: source address |
630 | * @dst: destination address |
631 | * @data: payload of message |
632 | * @len: length of payload |
633 | * @wait: indicates whether caller should block in case no TX buffers available |
634 | * |
635 | * This function is the base implementation for all of the rpmsg sending API. |
636 | * |
637 | * It will send @data of length @len to @dst, and say it's from @src. The |
638 | * message will be sent to the remote processor which the @rpdev channel |
639 | * belongs to. |
640 | * |
641 | * The message is sent using one of the TX buffers that are available for |
642 | * communication with this remote processor. |
643 | * |
644 | * If @wait is true, the caller will be blocked until either a TX buffer is |
645 | * available, or 15 seconds elapses (we don't want callers to |
646 | * sleep indefinitely due to misbehaving remote processors), and in that |
647 | * case -ERESTARTSYS is returned. The number '15' itself was picked |
648 | * arbitrarily; there's little point in asking drivers to provide a timeout |
649 | * value themselves. |
650 | * |
651 | * Otherwise, if @wait is false, and there are no TX buffers available, |
652 | * the function will immediately fail, and -ENOMEM will be returned. |
653 | * |
654 | * Normally drivers shouldn't use this function directly; instead, drivers |
655 | * should use the appropriate rpmsg_{try}send{to, _offchannel} API |
656 | * (see include/linux/rpmsg.h). |
657 | * |
658 | * Returns 0 on success and an appropriate error value on failure. |
659 | */ |
660 | int rpmsg_send_offchannel_raw(struct rpmsg_channel *rpdev, u32 src, u32 dst, |
661 | void *data, int len, bool wait) |
662 | { |
663 | struct virtproc_info *vrp = rpdev->vrp; |
664 | struct device *dev = &rpdev->dev; |
665 | struct scatterlist sg; |
666 | struct rpmsg_hdr *msg; |
667 | int err; |
668 | |
669 | /* bcasting isn't allowed */ |
670 | if (src == RPMSG_ADDR_ANY || dst == RPMSG_ADDR_ANY) { |
671 | dev_err(dev, "invalid addr (src 0x%x, dst 0x%x)\n", src, dst); |
672 | return -EINVAL; |
673 | } |
674 | |
675 | /* |
676 | * We currently use fixed-sized buffers, and therefore the payload |
677 | * length is limited. |
678 | * |
679 | * One of the possible improvements here is either to support |
680 | * user-provided buffers (and then we can also support zero-copy |
681 | * messaging), or to improve the buffer allocator, to support |
682 | * variable-length buffer sizes. |
683 | */ |
684 | if (len > RPMSG_BUF_SIZE - sizeof(struct rpmsg_hdr)) { |
685 | dev_err(dev, "message is too big (%d)\n", len); |
686 | return -EMSGSIZE; |
687 | } |
688 | |
689 | /* grab a buffer */ |
690 | msg = get_a_tx_buf(vrp); |
691 | if (!msg && !wait) |
692 | return -ENOMEM; |
693 | |
694 | /* no free buffer ? wait for one (but bail after 15 seconds) */ |
695 | while (!msg) { |
696 | /* enable "tx-complete" interrupts, if not already enabled */ |
697 | rpmsg_upref_sleepers(vrp); |
698 | |
699 | /* |
700 | * sleep until a free buffer is available or 15 secs elapse. |
701 | * the timeout period is not configurable because there's |
702 | * little point in asking drivers to specify that. |
703 | * if later this happens to be required, it'd be easy to add. |
704 | */ |
705 | err = wait_event_interruptible_timeout(vrp->sendq, |
706 | (msg = get_a_tx_buf(vrp)), |
707 | msecs_to_jiffies(15000)); |
708 | |
709 | /* disable "tx-complete" interrupts if we're the last sleeper */ |
710 | rpmsg_downref_sleepers(vrp); |
711 | |
712 | /* timeout ? */ |
713 | if (!err) { |
714 | dev_err(dev, "timeout waiting for a tx buffer\n"); |
715 | return -ERESTARTSYS; |
716 | } |
717 | } |
718 | |
719 | msg->len = len; |
720 | msg->flags = 0; |
721 | msg->src = src; |
722 | msg->dst = dst; |
723 | msg->reserved = 0; |
724 | memcpy(msg->data, data, len); |
725 | |
726 | dev_dbg(dev, "TX From 0x%x, To 0x%x, Len %d, Flags %d, Reserved %d\n", |
727 | msg->src, msg->dst, msg->len, |
728 | msg->flags, msg->reserved); |
729 | print_hex_dump(KERN_DEBUG, "rpmsg_virtio TX: ", DUMP_PREFIX_NONE, 16, 1, |
730 | msg, sizeof(*msg) + msg->len, true); |
731 | |
732 | sg_init_one(&sg, msg, sizeof(*msg) + len); |
733 | |
734 | mutex_lock(&vrp->tx_lock); |
735 | |
736 | /* add message to the remote processor's virtqueue */ |
737 | err = virtqueue_add_buf(vrp->svq, &sg, 1, 0, msg, GFP_KERNEL); |
738 | if (err < 0) { |
739 | /* |
740 | * need to reclaim the buffer here, otherwise it's lost |
741 | * (memory won't leak, but rpmsg won't use it again for TX). |
742 | * this will wait for a buffer management overhaul. |
743 | */ |
744 | dev_err(dev, "virtqueue_add_buf failed: %d\n", err); |
745 | goto out; |
746 | } |
747 | |
748 | /* tell the remote processor it has a pending message to read */ |
749 | virtqueue_kick(vrp->svq); |
750 | |
751 | err = 0; |
752 | out: |
753 | mutex_unlock(&vrp->tx_lock); |
754 | return err; |
755 | } |
756 | EXPORT_SYMBOL(rpmsg_send_offchannel_raw); |
757 | |
758 | /* called when an rx buffer is used, and it's time to digest a message */ |
759 | static void rpmsg_recv_done(struct virtqueue *rvq) |
760 | { |
761 | struct rpmsg_hdr *msg; |
762 | unsigned int len; |
763 | struct rpmsg_endpoint *ept; |
764 | struct scatterlist sg; |
765 | struct virtproc_info *vrp = rvq->vdev->priv; |
766 | struct device *dev = &rvq->vdev->dev; |
767 | int err; |
768 | |
769 | msg = virtqueue_get_buf(rvq, &len); |
770 | if (!msg) { |
771 | dev_err(dev, "uhm, incoming signal, but no used buffer ?\n"); |
772 | return; |
773 | } |
774 | |
775 | dev_dbg(dev, "From: 0x%x, To: 0x%x, Len: %d, Flags: %d, Reserved: %d\n", |
776 | msg->src, msg->dst, msg->len, |
777 | msg->flags, msg->reserved); |
778 | print_hex_dump(KERN_DEBUG, "rpmsg_virtio RX: ", DUMP_PREFIX_NONE, 16, 1, |
779 | msg, sizeof(*msg) + msg->len, true); |
780 | |
781 | /* |
782 | * We currently use fixed-sized buffers, so trivially sanitize |
783 | * the reported payload length. |
784 | */ |
785 | if (len > RPMSG_BUF_SIZE || |
786 | msg->len > (len - sizeof(struct rpmsg_hdr))) { |
787 | dev_warn(dev, "inbound msg too big: (%d, %d)\n", len, msg->len); |
788 | return; |
789 | } |
790 | |
791 | /* use the dst addr to fetch the callback of the appropriate user */ |
792 | mutex_lock(&vrp->endpoints_lock); |
793 | ept = idr_find(&vrp->endpoints, msg->dst); |
794 | mutex_unlock(&vrp->endpoints_lock); |
795 | |
796 | if (ept && ept->cb) |
797 | ept->cb(ept->rpdev, msg->data, msg->len, ept->priv, msg->src); |
798 | else |
799 | dev_warn(dev, "msg received with no recepient\n"); |
800 | |
801 | /* publish the real size of the buffer */ |
802 | sg_init_one(&sg, msg, RPMSG_BUF_SIZE); |
803 | |
804 | /* add the buffer back to the remote processor's virtqueue */ |
805 | err = virtqueue_add_buf(vrp->rvq, &sg, 0, 1, msg, GFP_KERNEL); |
806 | if (err < 0) { |
807 | dev_err(dev, "failed to add a virtqueue buffer: %d\n", err); |
808 | return; |
809 | } |
810 | |
811 | /* tell the remote processor we added another available rx buffer */ |
812 | virtqueue_kick(vrp->rvq); |
813 | } |
814 | |
815 | /* |
816 | * This is invoked whenever the remote processor completed processing |
817 | * a TX msg we just sent it, and the buffer is put back to the used ring. |
818 | * |
819 | * Normally, though, we suppress this "tx complete" interrupt in order to |
820 | * avoid the incurred overhead. |
821 | */ |
822 | static void rpmsg_xmit_done(struct virtqueue *svq) |
823 | { |
824 | struct virtproc_info *vrp = svq->vdev->priv; |
825 | |
826 | dev_dbg(&svq->vdev->dev, "%s\n", __func__); |
827 | |
828 | /* wake up potential senders that are waiting for a tx buffer */ |
829 | wake_up_interruptible(&vrp->sendq); |
830 | } |
831 | |
832 | /* invoked when a name service announcement arrives */ |
833 | static void rpmsg_ns_cb(struct rpmsg_channel *rpdev, void *data, int len, |
834 | void *priv, u32 src) |
835 | { |
836 | struct rpmsg_ns_msg *msg = data; |
837 | struct rpmsg_channel *newch; |
838 | struct rpmsg_channel_info chinfo; |
839 | struct virtproc_info *vrp = priv; |
840 | struct device *dev = &vrp->vdev->dev; |
841 | int ret; |
842 | |
843 | print_hex_dump(KERN_DEBUG, "NS announcement: ", |
844 | DUMP_PREFIX_NONE, 16, 1, |
845 | data, len, true); |
846 | |
847 | if (len != sizeof(*msg)) { |
848 | dev_err(dev, "malformed ns msg (%d)\n", len); |
849 | return; |
850 | } |
851 | |
852 | /* |
853 | * the name service ept does _not_ belong to a real rpmsg channel, |
854 | * and is handled by the rpmsg bus itself. |
855 | * for sanity reasons, make sure a valid rpdev has _not_ sneaked |
856 | * in somehow. |
857 | */ |
858 | if (rpdev) { |
859 | dev_err(dev, "anomaly: ns ept has an rpdev handle\n"); |
860 | return; |
861 | } |
862 | |
863 | /* don't trust the remote processor for null terminating the name */ |
864 | msg->name[RPMSG_NAME_SIZE - 1] = '\0'; |
865 | |
866 | dev_info(dev, "%sing channel %s addr 0x%x\n", |
867 | msg->flags & RPMSG_NS_DESTROY ? "destroy" : "creat", |
868 | msg->name, msg->addr); |
869 | |
870 | strncpy(chinfo.name, msg->name, sizeof(chinfo.name)); |
871 | chinfo.src = RPMSG_ADDR_ANY; |
872 | chinfo.dst = msg->addr; |
873 | |
874 | if (msg->flags & RPMSG_NS_DESTROY) { |
875 | ret = rpmsg_destroy_channel(vrp, &chinfo); |
876 | if (ret) |
877 | dev_err(dev, "rpmsg_destroy_channel failed: %d\n", ret); |
878 | } else { |
879 | newch = rpmsg_create_channel(vrp, &chinfo); |
880 | if (!newch) |
881 | dev_err(dev, "rpmsg_create_channel failed\n"); |
882 | } |
883 | } |
884 | |
885 | static int rpmsg_probe(struct virtio_device *vdev) |
886 | { |
887 | vq_callback_t *vq_cbs[] = { rpmsg_recv_done, rpmsg_xmit_done }; |
888 | const char *names[] = { "input", "output" }; |
889 | struct virtqueue *vqs[2]; |
890 | struct virtproc_info *vrp; |
891 | void *bufs_va; |
892 | int err = 0, i; |
893 | |
894 | vrp = kzalloc(sizeof(*vrp), GFP_KERNEL); |
895 | if (!vrp) |
896 | return -ENOMEM; |
897 | |
898 | vrp->vdev = vdev; |
899 | |
900 | idr_init(&vrp->endpoints); |
901 | mutex_init(&vrp->endpoints_lock); |
902 | mutex_init(&vrp->tx_lock); |
903 | init_waitqueue_head(&vrp->sendq); |
904 | |
905 | /* We expect two virtqueues, rx and tx (and in this order) */ |
906 | err = vdev->config->find_vqs(vdev, 2, vqs, vq_cbs, names); |
907 | if (err) |
908 | goto free_vrp; |
909 | |
910 | vrp->rvq = vqs[0]; |
911 | vrp->svq = vqs[1]; |
912 | |
913 | /* allocate coherent memory for the buffers */ |
914 | bufs_va = dma_alloc_coherent(vdev->dev.parent, RPMSG_TOTAL_BUF_SPACE, |
915 | &vrp->bufs_dma, GFP_KERNEL); |
916 | if (!bufs_va) |
917 | goto vqs_del; |
918 | |
919 | dev_dbg(&vdev->dev, "buffers: va %p, dma 0x%llx\n", bufs_va, |
920 | (unsigned long long)vrp->bufs_dma); |
921 | |
922 | /* half of the buffers is dedicated for RX */ |
923 | vrp->rbufs = bufs_va; |
924 | |
925 | /* and half is dedicated for TX */ |
926 | vrp->sbufs = bufs_va + RPMSG_TOTAL_BUF_SPACE / 2; |
927 | |
928 | /* set up the receive buffers */ |
929 | for (i = 0; i < RPMSG_NUM_BUFS / 2; i++) { |
930 | struct scatterlist sg; |
931 | void *cpu_addr = vrp->rbufs + i * RPMSG_BUF_SIZE; |
932 | |
933 | sg_init_one(&sg, cpu_addr, RPMSG_BUF_SIZE); |
934 | |
935 | err = virtqueue_add_buf(vrp->rvq, &sg, 0, 1, cpu_addr, |
936 | GFP_KERNEL); |
937 | WARN_ON(err < 0); /* sanity check; this can't really happen */ |
938 | } |
939 | |
940 | /* suppress "tx-complete" interrupts */ |
941 | virtqueue_disable_cb(vrp->svq); |
942 | |
943 | vdev->priv = vrp; |
944 | |
945 | /* if supported by the remote processor, enable the name service */ |
946 | if (virtio_has_feature(vdev, VIRTIO_RPMSG_F_NS)) { |
947 | /* a dedicated endpoint handles the name service msgs */ |
948 | vrp->ns_ept = __rpmsg_create_ept(vrp, NULL, rpmsg_ns_cb, |
949 | vrp, RPMSG_NS_ADDR); |
950 | if (!vrp->ns_ept) { |
951 | dev_err(&vdev->dev, "failed to create the ns ept\n"); |
952 | err = -ENOMEM; |
953 | goto free_coherent; |
954 | } |
955 | } |
956 | |
957 | /* tell the remote processor it can start sending messages */ |
958 | virtqueue_kick(vrp->rvq); |
959 | |
960 | dev_info(&vdev->dev, "rpmsg host is online\n"); |
961 | |
962 | return 0; |
963 | |
964 | free_coherent: |
965 | dma_free_coherent(vdev->dev.parent, RPMSG_TOTAL_BUF_SPACE, bufs_va, |
966 | vrp->bufs_dma); |
967 | vqs_del: |
968 | vdev->config->del_vqs(vrp->vdev); |
969 | free_vrp: |
970 | kfree(vrp); |
971 | return err; |
972 | } |
973 | |
974 | static int rpmsg_remove_device(struct device *dev, void *data) |
975 | { |
976 | device_unregister(dev); |
977 | |
978 | return 0; |
979 | } |
980 | |
981 | static void __devexit rpmsg_remove(struct virtio_device *vdev) |
982 | { |
983 | struct virtproc_info *vrp = vdev->priv; |
984 | int ret; |
985 | |
986 | vdev->config->reset(vdev); |
987 | |
988 | ret = device_for_each_child(&vdev->dev, NULL, rpmsg_remove_device); |
989 | if (ret) |
990 | dev_warn(&vdev->dev, "can't remove rpmsg device: %d\n", ret); |
991 | |
992 | if (vrp->ns_ept) |
993 | __rpmsg_destroy_ept(vrp, vrp->ns_ept); |
994 | |
995 | idr_remove_all(&vrp->endpoints); |
996 | idr_destroy(&vrp->endpoints); |
997 | |
998 | vdev->config->del_vqs(vrp->vdev); |
999 | |
1000 | dma_free_coherent(vdev->dev.parent, RPMSG_TOTAL_BUF_SPACE, |
1001 | vrp->rbufs, vrp->bufs_dma); |
1002 | |
1003 | kfree(vrp); |
1004 | } |
1005 | |
1006 | static struct virtio_device_id id_table[] = { |
1007 | { VIRTIO_ID_RPMSG, VIRTIO_DEV_ANY_ID }, |
1008 | { 0 }, |
1009 | }; |
1010 | |
1011 | static unsigned int features[] = { |
1012 | VIRTIO_RPMSG_F_NS, |
1013 | }; |
1014 | |
1015 | static struct virtio_driver virtio_ipc_driver = { |
1016 | .feature_table = features, |
1017 | .feature_table_size = ARRAY_SIZE(features), |
1018 | .driver.name = KBUILD_MODNAME, |
1019 | .driver.owner = THIS_MODULE, |
1020 | .id_table = id_table, |
1021 | .probe = rpmsg_probe, |
1022 | .remove = __devexit_p(rpmsg_remove), |
1023 | }; |
1024 | |
1025 | static int __init rpmsg_init(void) |
1026 | { |
1027 | int ret; |
1028 | |
1029 | ret = bus_register(&rpmsg_bus); |
1030 | if (ret) { |
1031 | pr_err("failed to register rpmsg bus: %d\n", ret); |
1032 | return ret; |
1033 | } |
1034 | |
1035 | ret = register_virtio_driver(&virtio_ipc_driver); |
1036 | if (ret) { |
1037 | pr_err("failed to register virtio driver: %d\n", ret); |
1038 | bus_unregister(&rpmsg_bus); |
1039 | } |
1040 | |
1041 | return ret; |
1042 | } |
1043 | module_init(rpmsg_init); |
1044 | |
1045 | static void __exit rpmsg_fini(void) |
1046 | { |
1047 | unregister_virtio_driver(&virtio_ipc_driver); |
1048 | bus_unregister(&rpmsg_bus); |
1049 | } |
1050 | module_exit(rpmsg_fini); |
1051 | |
1052 | MODULE_DEVICE_TABLE(virtio, id_table); |
1053 | MODULE_DESCRIPTION("Virtio-based remote processor messaging bus"); |
1054 | MODULE_LICENSE("GPL v2"); |
1055 |
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