1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * |
4 | * Copyright (C) 2005 Mike Isely <isely@pobox.com> |
5 | */ |
6 | |
7 | #include "pvrusb2-ioread.h" |
8 | #include "pvrusb2-debug.h" |
9 | #include <linux/errno.h> |
10 | #include <linux/string.h> |
11 | #include <linux/mm.h> |
12 | #include <linux/slab.h> |
13 | #include <linux/mutex.h> |
14 | #include <linux/uaccess.h> |
15 | |
16 | #define BUFFER_COUNT 32 |
17 | #define BUFFER_SIZE PAGE_ALIGN(0x4000) |
18 | |
19 | struct pvr2_ioread { |
20 | struct pvr2_stream *stream; |
21 | char *buffer_storage[BUFFER_COUNT]; |
22 | char *sync_key_ptr; |
23 | unsigned int sync_key_len; |
24 | unsigned int sync_buf_offs; |
25 | unsigned int sync_state; |
26 | unsigned int sync_trashed_count; |
27 | int enabled; // Streaming is on |
28 | int spigot_open; // OK to pass data to client |
29 | int stream_running; // Passing data to client now |
30 | |
31 | /* State relevant to current buffer being read */ |
32 | struct pvr2_buffer *c_buf; |
33 | char *c_data_ptr; |
34 | unsigned int c_data_len; |
35 | unsigned int c_data_offs; |
36 | struct mutex mutex; |
37 | }; |
38 | |
39 | static int pvr2_ioread_init(struct pvr2_ioread *cp) |
40 | { |
41 | unsigned int idx; |
42 | |
43 | cp->stream = NULL; |
44 | mutex_init(&cp->mutex); |
45 | |
46 | for (idx = 0; idx < BUFFER_COUNT; idx++) { |
47 | cp->buffer_storage[idx] = kmalloc(BUFFER_SIZE,GFP_KERNEL); |
48 | if (!(cp->buffer_storage[idx])) break; |
49 | } |
50 | |
51 | if (idx < BUFFER_COUNT) { |
52 | // An allocation appears to have failed |
53 | for (idx = 0; idx < BUFFER_COUNT; idx++) { |
54 | if (!(cp->buffer_storage[idx])) continue; |
55 | kfree(objp: cp->buffer_storage[idx]); |
56 | } |
57 | return -ENOMEM; |
58 | } |
59 | return 0; |
60 | } |
61 | |
62 | static void pvr2_ioread_done(struct pvr2_ioread *cp) |
63 | { |
64 | unsigned int idx; |
65 | |
66 | pvr2_ioread_setup(cp,NULL); |
67 | for (idx = 0; idx < BUFFER_COUNT; idx++) { |
68 | if (!(cp->buffer_storage[idx])) continue; |
69 | kfree(objp: cp->buffer_storage[idx]); |
70 | } |
71 | } |
72 | |
73 | struct pvr2_ioread *pvr2_ioread_create(void) |
74 | { |
75 | struct pvr2_ioread *cp; |
76 | cp = kzalloc(size: sizeof(*cp),GFP_KERNEL); |
77 | if (!cp) return NULL; |
78 | pvr2_trace(PVR2_TRACE_STRUCT,"pvr2_ioread_create id=%p" ,cp); |
79 | if (pvr2_ioread_init(cp) < 0) { |
80 | kfree(objp: cp); |
81 | return NULL; |
82 | } |
83 | return cp; |
84 | } |
85 | |
86 | void pvr2_ioread_destroy(struct pvr2_ioread *cp) |
87 | { |
88 | if (!cp) return; |
89 | pvr2_ioread_done(cp); |
90 | pvr2_trace(PVR2_TRACE_STRUCT,"pvr2_ioread_destroy id=%p" ,cp); |
91 | if (cp->sync_key_ptr) { |
92 | kfree(objp: cp->sync_key_ptr); |
93 | cp->sync_key_ptr = NULL; |
94 | } |
95 | kfree(objp: cp); |
96 | } |
97 | |
98 | void pvr2_ioread_set_sync_key(struct pvr2_ioread *cp, |
99 | const char *sync_key_ptr, |
100 | unsigned int sync_key_len) |
101 | { |
102 | if (!cp) return; |
103 | |
104 | if (!sync_key_ptr) sync_key_len = 0; |
105 | if ((sync_key_len == cp->sync_key_len) && |
106 | ((!sync_key_len) || |
107 | (!memcmp(p: sync_key_ptr,q: cp->sync_key_ptr,size: sync_key_len)))) return; |
108 | |
109 | if (sync_key_len != cp->sync_key_len) { |
110 | if (cp->sync_key_ptr) { |
111 | kfree(objp: cp->sync_key_ptr); |
112 | cp->sync_key_ptr = NULL; |
113 | } |
114 | cp->sync_key_len = 0; |
115 | if (sync_key_len) { |
116 | cp->sync_key_ptr = kmalloc(size: sync_key_len,GFP_KERNEL); |
117 | if (cp->sync_key_ptr) { |
118 | cp->sync_key_len = sync_key_len; |
119 | } |
120 | } |
121 | } |
122 | if (!cp->sync_key_len) return; |
123 | memcpy(cp->sync_key_ptr,sync_key_ptr,cp->sync_key_len); |
124 | } |
125 | |
126 | static void pvr2_ioread_stop(struct pvr2_ioread *cp) |
127 | { |
128 | if (!(cp->enabled)) return; |
129 | pvr2_trace(PVR2_TRACE_START_STOP, |
130 | "/*---TRACE_READ---*/ pvr2_ioread_stop id=%p" ,cp); |
131 | pvr2_stream_kill(cp->stream); |
132 | cp->c_buf = NULL; |
133 | cp->c_data_ptr = NULL; |
134 | cp->c_data_len = 0; |
135 | cp->c_data_offs = 0; |
136 | cp->enabled = 0; |
137 | cp->stream_running = 0; |
138 | cp->spigot_open = 0; |
139 | if (cp->sync_state) { |
140 | pvr2_trace(PVR2_TRACE_DATA_FLOW, |
141 | "/*---TRACE_READ---*/ sync_state <== 0" ); |
142 | cp->sync_state = 0; |
143 | } |
144 | } |
145 | |
146 | static int pvr2_ioread_start(struct pvr2_ioread *cp) |
147 | { |
148 | int stat; |
149 | struct pvr2_buffer *bp; |
150 | if (cp->enabled) return 0; |
151 | if (!(cp->stream)) return 0; |
152 | pvr2_trace(PVR2_TRACE_START_STOP, |
153 | "/*---TRACE_READ---*/ pvr2_ioread_start id=%p" ,cp); |
154 | while ((bp = pvr2_stream_get_idle_buffer(cp->stream)) != NULL) { |
155 | stat = pvr2_buffer_queue(bp); |
156 | if (stat < 0) { |
157 | pvr2_trace(PVR2_TRACE_DATA_FLOW, |
158 | "/*---TRACE_READ---*/ pvr2_ioread_start id=%p error=%d" , |
159 | cp,stat); |
160 | pvr2_ioread_stop(cp); |
161 | return stat; |
162 | } |
163 | } |
164 | cp->enabled = !0; |
165 | cp->c_buf = NULL; |
166 | cp->c_data_ptr = NULL; |
167 | cp->c_data_len = 0; |
168 | cp->c_data_offs = 0; |
169 | cp->stream_running = 0; |
170 | if (cp->sync_key_len) { |
171 | pvr2_trace(PVR2_TRACE_DATA_FLOW, |
172 | "/*---TRACE_READ---*/ sync_state <== 1" ); |
173 | cp->sync_state = 1; |
174 | cp->sync_trashed_count = 0; |
175 | cp->sync_buf_offs = 0; |
176 | } |
177 | cp->spigot_open = 0; |
178 | return 0; |
179 | } |
180 | |
181 | struct pvr2_stream *pvr2_ioread_get_stream(struct pvr2_ioread *cp) |
182 | { |
183 | return cp->stream; |
184 | } |
185 | |
186 | int pvr2_ioread_setup(struct pvr2_ioread *cp,struct pvr2_stream *sp) |
187 | { |
188 | int ret; |
189 | unsigned int idx; |
190 | struct pvr2_buffer *bp; |
191 | |
192 | mutex_lock(&cp->mutex); |
193 | do { |
194 | if (cp->stream) { |
195 | pvr2_trace(PVR2_TRACE_START_STOP, |
196 | "/*---TRACE_READ---*/ pvr2_ioread_setup (tear-down) id=%p" , |
197 | cp); |
198 | pvr2_ioread_stop(cp); |
199 | pvr2_stream_kill(cp->stream); |
200 | if (pvr2_stream_get_buffer_count(cp->stream)) { |
201 | pvr2_stream_set_buffer_count(cp->stream,0); |
202 | } |
203 | cp->stream = NULL; |
204 | } |
205 | if (sp) { |
206 | pvr2_trace(PVR2_TRACE_START_STOP, |
207 | "/*---TRACE_READ---*/ pvr2_ioread_setup (setup) id=%p" , |
208 | cp); |
209 | pvr2_stream_kill(sp); |
210 | ret = pvr2_stream_set_buffer_count(sp,BUFFER_COUNT); |
211 | if (ret < 0) { |
212 | mutex_unlock(lock: &cp->mutex); |
213 | return ret; |
214 | } |
215 | for (idx = 0; idx < BUFFER_COUNT; idx++) { |
216 | bp = pvr2_stream_get_buffer(sp,id: idx); |
217 | pvr2_buffer_set_buffer(bp, |
218 | ptr: cp->buffer_storage[idx], |
219 | BUFFER_SIZE); |
220 | } |
221 | cp->stream = sp; |
222 | } |
223 | } while (0); |
224 | mutex_unlock(lock: &cp->mutex); |
225 | |
226 | return 0; |
227 | } |
228 | |
229 | int pvr2_ioread_set_enabled(struct pvr2_ioread *cp,int fl) |
230 | { |
231 | int ret = 0; |
232 | if ((!fl) == (!(cp->enabled))) return ret; |
233 | |
234 | mutex_lock(&cp->mutex); |
235 | do { |
236 | if (fl) { |
237 | ret = pvr2_ioread_start(cp); |
238 | } else { |
239 | pvr2_ioread_stop(cp); |
240 | } |
241 | } while (0); |
242 | mutex_unlock(lock: &cp->mutex); |
243 | return ret; |
244 | } |
245 | |
246 | static int pvr2_ioread_get_buffer(struct pvr2_ioread *cp) |
247 | { |
248 | int stat; |
249 | |
250 | while (cp->c_data_len <= cp->c_data_offs) { |
251 | if (cp->c_buf) { |
252 | // Flush out current buffer first. |
253 | stat = pvr2_buffer_queue(cp->c_buf); |
254 | if (stat < 0) { |
255 | // Streaming error... |
256 | pvr2_trace(PVR2_TRACE_DATA_FLOW, |
257 | "/*---TRACE_READ---*/ pvr2_ioread_read id=%p queue_error=%d" , |
258 | cp,stat); |
259 | pvr2_ioread_stop(cp); |
260 | return 0; |
261 | } |
262 | cp->c_buf = NULL; |
263 | cp->c_data_ptr = NULL; |
264 | cp->c_data_len = 0; |
265 | cp->c_data_offs = 0; |
266 | } |
267 | // Now get a freshly filled buffer. |
268 | cp->c_buf = pvr2_stream_get_ready_buffer(cp->stream); |
269 | if (!cp->c_buf) break; // Nothing ready; done. |
270 | cp->c_data_len = pvr2_buffer_get_count(cp->c_buf); |
271 | if (!cp->c_data_len) { |
272 | // Nothing transferred. Was there an error? |
273 | stat = pvr2_buffer_get_status(cp->c_buf); |
274 | if (stat < 0) { |
275 | // Streaming error... |
276 | pvr2_trace(PVR2_TRACE_DATA_FLOW, |
277 | "/*---TRACE_READ---*/ pvr2_ioread_read id=%p buffer_error=%d" , |
278 | cp,stat); |
279 | pvr2_ioread_stop(cp); |
280 | // Give up. |
281 | return 0; |
282 | } |
283 | // Start over... |
284 | continue; |
285 | } |
286 | cp->c_data_offs = 0; |
287 | cp->c_data_ptr = cp->buffer_storage[ |
288 | pvr2_buffer_get_id(cp->c_buf)]; |
289 | } |
290 | return !0; |
291 | } |
292 | |
293 | static void pvr2_ioread_filter(struct pvr2_ioread *cp) |
294 | { |
295 | unsigned int idx; |
296 | if (!cp->enabled) return; |
297 | if (cp->sync_state != 1) return; |
298 | |
299 | // Search the stream for our synchronization key. This is made |
300 | // complicated by the fact that in order to be honest with |
301 | // ourselves here we must search across buffer boundaries... |
302 | mutex_lock(&cp->mutex); |
303 | while (1) { |
304 | // Ensure we have a buffer |
305 | if (!pvr2_ioread_get_buffer(cp)) break; |
306 | if (!cp->c_data_len) break; |
307 | |
308 | // Now walk the buffer contents until we match the key or |
309 | // run out of buffer data. |
310 | for (idx = cp->c_data_offs; idx < cp->c_data_len; idx++) { |
311 | if (cp->sync_buf_offs >= cp->sync_key_len) break; |
312 | if (cp->c_data_ptr[idx] == |
313 | cp->sync_key_ptr[cp->sync_buf_offs]) { |
314 | // Found the next key byte |
315 | (cp->sync_buf_offs)++; |
316 | } else { |
317 | // Whoops, mismatched. Start key over... |
318 | cp->sync_buf_offs = 0; |
319 | } |
320 | } |
321 | |
322 | // Consume what we've walked through |
323 | cp->c_data_offs += idx; |
324 | cp->sync_trashed_count += idx; |
325 | |
326 | // If we've found the key, then update state and get out. |
327 | if (cp->sync_buf_offs >= cp->sync_key_len) { |
328 | cp->sync_trashed_count -= cp->sync_key_len; |
329 | pvr2_trace(PVR2_TRACE_DATA_FLOW, |
330 | "/*---TRACE_READ---*/ sync_state <== 2 (skipped %u bytes)" , |
331 | cp->sync_trashed_count); |
332 | cp->sync_state = 2; |
333 | cp->sync_buf_offs = 0; |
334 | break; |
335 | } |
336 | |
337 | if (cp->c_data_offs < cp->c_data_len) { |
338 | // Sanity check - should NEVER get here |
339 | pvr2_trace(PVR2_TRACE_ERROR_LEGS, |
340 | "ERROR: pvr2_ioread filter sync problem len=%u offs=%u" , |
341 | cp->c_data_len,cp->c_data_offs); |
342 | // Get out so we don't get stuck in an infinite |
343 | // loop. |
344 | break; |
345 | } |
346 | |
347 | continue; // (for clarity) |
348 | } |
349 | mutex_unlock(lock: &cp->mutex); |
350 | } |
351 | |
352 | int pvr2_ioread_avail(struct pvr2_ioread *cp) |
353 | { |
354 | int ret; |
355 | if (!(cp->enabled)) { |
356 | // Stream is not enabled; so this is an I/O error |
357 | return -EIO; |
358 | } |
359 | |
360 | if (cp->sync_state == 1) { |
361 | pvr2_ioread_filter(cp); |
362 | if (cp->sync_state == 1) return -EAGAIN; |
363 | } |
364 | |
365 | ret = 0; |
366 | if (cp->stream_running) { |
367 | if (!pvr2_stream_get_ready_count(cp->stream)) { |
368 | // No data available at all right now. |
369 | ret = -EAGAIN; |
370 | } |
371 | } else { |
372 | if (pvr2_stream_get_ready_count(cp->stream) < BUFFER_COUNT/2) { |
373 | // Haven't buffered up enough yet; try again later |
374 | ret = -EAGAIN; |
375 | } |
376 | } |
377 | |
378 | if ((!(cp->spigot_open)) != (!(ret == 0))) { |
379 | cp->spigot_open = (ret == 0); |
380 | pvr2_trace(PVR2_TRACE_DATA_FLOW, |
381 | "/*---TRACE_READ---*/ data is %s" , |
382 | cp->spigot_open ? "available" : "pending" ); |
383 | } |
384 | |
385 | return ret; |
386 | } |
387 | |
388 | int pvr2_ioread_read(struct pvr2_ioread *cp,void __user *buf,unsigned int cnt) |
389 | { |
390 | unsigned int copied_cnt; |
391 | unsigned int bcnt; |
392 | const char *src; |
393 | int stat; |
394 | int ret = 0; |
395 | unsigned int req_cnt = cnt; |
396 | |
397 | if (!cnt) { |
398 | pvr2_trace(PVR2_TRACE_TRAP, |
399 | "/*---TRACE_READ---*/ pvr2_ioread_read id=%p ZERO Request? Returning zero." , |
400 | cp); |
401 | return 0; |
402 | } |
403 | |
404 | stat = pvr2_ioread_avail(cp); |
405 | if (stat < 0) return stat; |
406 | |
407 | cp->stream_running = !0; |
408 | |
409 | mutex_lock(&cp->mutex); |
410 | do { |
411 | |
412 | // Suck data out of the buffers and copy to the user |
413 | copied_cnt = 0; |
414 | if (!buf) cnt = 0; |
415 | while (1) { |
416 | if (!pvr2_ioread_get_buffer(cp)) { |
417 | ret = -EIO; |
418 | break; |
419 | } |
420 | |
421 | if (!cnt) break; |
422 | |
423 | if (cp->sync_state == 2) { |
424 | // We're repeating the sync key data into |
425 | // the stream. |
426 | src = cp->sync_key_ptr + cp->sync_buf_offs; |
427 | bcnt = cp->sync_key_len - cp->sync_buf_offs; |
428 | } else { |
429 | // Normal buffer copy |
430 | src = cp->c_data_ptr + cp->c_data_offs; |
431 | bcnt = cp->c_data_len - cp->c_data_offs; |
432 | } |
433 | |
434 | if (!bcnt) break; |
435 | |
436 | // Don't run past user's buffer |
437 | if (bcnt > cnt) bcnt = cnt; |
438 | |
439 | if (copy_to_user(to: buf,from: src,n: bcnt)) { |
440 | // User supplied a bad pointer? |
441 | // Give up - this *will* cause data |
442 | // to be lost. |
443 | ret = -EFAULT; |
444 | break; |
445 | } |
446 | cnt -= bcnt; |
447 | buf += bcnt; |
448 | copied_cnt += bcnt; |
449 | |
450 | if (cp->sync_state == 2) { |
451 | // Update offset inside sync key that we're |
452 | // repeating back out. |
453 | cp->sync_buf_offs += bcnt; |
454 | if (cp->sync_buf_offs >= cp->sync_key_len) { |
455 | // Consumed entire key; switch mode |
456 | // to normal. |
457 | pvr2_trace(PVR2_TRACE_DATA_FLOW, |
458 | "/*---TRACE_READ---*/ sync_state <== 0" ); |
459 | cp->sync_state = 0; |
460 | } |
461 | } else { |
462 | // Update buffer offset. |
463 | cp->c_data_offs += bcnt; |
464 | } |
465 | } |
466 | |
467 | } while (0); |
468 | mutex_unlock(lock: &cp->mutex); |
469 | |
470 | if (!ret) { |
471 | if (copied_cnt) { |
472 | // If anything was copied, return that count |
473 | ret = copied_cnt; |
474 | } else { |
475 | // Nothing copied; suggest to caller that another |
476 | // attempt should be tried again later |
477 | ret = -EAGAIN; |
478 | } |
479 | } |
480 | |
481 | pvr2_trace(PVR2_TRACE_DATA_FLOW, |
482 | "/*---TRACE_READ---*/ pvr2_ioread_read id=%p request=%d result=%d" , |
483 | cp,req_cnt,ret); |
484 | return ret; |
485 | } |
486 | |