drivers/media/usb/pvrusb2/pvrusb2-ioread.c

   1 /*
   2  *
   3  *
   4  *  Copyright (C) 2005 Mike Isely <isely@pobox.com>
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program; if not, write to the Free Software
  17  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  *
  19  */
  20
  21 #include "pvrusb2-ioread.h"
  22 #include "pvrusb2-debug.h"
  23 #include <linux/errno.h>
  24 #include <linux/string.h>
  25 #include <linux/mm.h>
  26 #include <linux/slab.h>
  27 #include <linux/mutex.h>
  28 #include <linux/uaccess.h>
  29
  30 #define BUFFER_COUNT 32
  31 #define BUFFER_SIZE PAGE_ALIGN(0x4000)
  32
  33 struct pvr2_ioread {
  34         struct pvr2_stream *stream;
  35         char *buffer_storage[BUFFER_COUNT];
  36         char *sync_key_ptr;
  37         unsigned int sync_key_len;
  38         unsigned int sync_buf_offs;
  39         unsigned int sync_state;
  40         unsigned int sync_trashed_count;
  41         int enabled;         // Streaming is on
  42         int spigot_open;     // OK to pass data to client
  43         int stream_running;  // Passing data to client now
  44
  45         /* State relevant to current buffer being read */
  46         struct pvr2_buffer *c_buf;
  47         char *c_data_ptr;
  48         unsigned int c_data_len;
  49         unsigned int c_data_offs;
  50         struct mutex mutex;
  51 };
  52
  53 static int pvr2_ioread_init(struct pvr2_ioread *cp)
  54 {
  55         unsigned int idx;
  56
  57         cp->stream = NULL;
  58         mutex_init(&cp->mutex);
  59
  60         for (idx = 0; idx < BUFFER_COUNT; idx++) {
  61                 cp->buffer_storage[idx] = kmalloc(BUFFER_SIZE,GFP_KERNEL);
  62                 if (!(cp->buffer_storage[idx])) break;
  63         }
  64
  65         if (idx < BUFFER_COUNT) {
  66                 // An allocation appears to have failed
  67                 for (idx = 0; idx < BUFFER_COUNT; idx++) {
  68                         if (!(cp->buffer_storage[idx])) continue;
  69                         kfree(cp->buffer_storage[idx]);
  70                 }
  71                 return -ENOMEM;
  72         }
  73         return 0;
  74 }
  75
  76 static void pvr2_ioread_done(struct pvr2_ioread *cp)
  77 {
  78         unsigned int idx;
  79
  80         pvr2_ioread_setup(cp,NULL);
  81         for (idx = 0; idx < BUFFER_COUNT; idx++) {
  82                 if (!(cp->buffer_storage[idx])) continue;
  83                 kfree(cp->buffer_storage[idx]);
  84         }
  85 }
  86
  87 struct pvr2_ioread *pvr2_ioread_create(void)
  88 {
  89         struct pvr2_ioread *cp;
  90         cp = kzalloc(sizeof(*cp),GFP_KERNEL);
  91         if (!cp) return NULL;
  92         pvr2_trace(PVR2_TRACE_STRUCT,"pvr2_ioread_create id=%p",cp);
  93         if (pvr2_ioread_init(cp) < 0) {
  94                 kfree(cp);
  95                 return NULL;
  96         }
  97         return cp;
  98 }
  99
 100 void pvr2_ioread_destroy(struct pvr2_ioread *cp)
 101 {
 102         if (!cp) return;
 103         pvr2_ioread_done(cp);
 104         pvr2_trace(PVR2_TRACE_STRUCT,"pvr2_ioread_destroy id=%p",cp);
 105         if (cp->sync_key_ptr) {
 106                 kfree(cp->sync_key_ptr);
 107                 cp->sync_key_ptr = NULL;
 108         }
 109         kfree(cp);
 110 }
 111
 112 void pvr2_ioread_set_sync_key(struct pvr2_ioread *cp,
 113                               const char *sync_key_ptr,
 114                               unsigned int sync_key_len)
 115 {
 116         if (!cp) return;
 117
 118         if (!sync_key_ptr) sync_key_len = 0;
 119         if ((sync_key_len == cp->sync_key_len) &&
 120             ((!sync_key_len) ||
 121              (!memcmp(sync_key_ptr,cp->sync_key_ptr,sync_key_len)))) return;
 122
 123         if (sync_key_len != cp->sync_key_len) {
 124                 if (cp->sync_key_ptr) {
 125                         kfree(cp->sync_key_ptr);
 126                         cp->sync_key_ptr = NULL;
 127                 }
 128                 cp->sync_key_len = 0;
 129                 if (sync_key_len) {
 130                         cp->sync_key_ptr = kmalloc(sync_key_len,GFP_KERNEL);
 131                         if (cp->sync_key_ptr) {
 132                                 cp->sync_key_len = sync_key_len;
 133                         }
 134                 }
 135         }
 136         if (!cp->sync_key_len) return;
 137         memcpy(cp->sync_key_ptr,sync_key_ptr,cp->sync_key_len);
 138 }
 139
 140 static void pvr2_ioread_stop(struct pvr2_ioread *cp)
 141 {
 142         if (!(cp->enabled)) return;
 143         pvr2_trace(PVR2_TRACE_START_STOP,
 144                    "/*---TRACE_READ---*/ pvr2_ioread_stop id=%p",cp);
 145         pvr2_stream_kill(cp->stream);
 146         cp->c_buf = NULL;
 147         cp->c_data_ptr = NULL;
 148         cp->c_data_len = 0;
 149         cp->c_data_offs = 0;
 150         cp->enabled = 0;
 151         cp->stream_running = 0;
 152         cp->spigot_open = 0;
 153         if (cp->sync_state) {
 154                 pvr2_trace(PVR2_TRACE_DATA_FLOW,
 155                            "/*---TRACE_READ---*/ sync_state <== 0");
 156                 cp->sync_state = 0;
 157         }
 158 }
 159
 160 static int pvr2_ioread_start(struct pvr2_ioread *cp)
 161 {
 162         int stat;
 163         struct pvr2_buffer *bp;
 164         if (cp->enabled) return 0;
 165         if (!(cp->stream)) return 0;
 166         pvr2_trace(PVR2_TRACE_START_STOP,
 167                    "/*---TRACE_READ---*/ pvr2_ioread_start id=%p",cp);
 168         while ((bp = pvr2_stream_get_idle_buffer(cp->stream)) != NULL) {
 169                 stat = pvr2_buffer_queue(bp);
 170                 if (stat < 0) {
 171                         pvr2_trace(PVR2_TRACE_DATA_FLOW,
 172                                    "/*---TRACE_READ---*/ pvr2_ioread_start id=%p error=%d",
 173                                    cp,stat);
 174                         pvr2_ioread_stop(cp);
 175                         return stat;
 176                 }
 177         }
 178         cp->enabled = !0;
 179         cp->c_buf = NULL;
 180         cp->c_data_ptr = NULL;
 181         cp->c_data_len = 0;
 182         cp->c_data_offs = 0;
 183         cp->stream_running = 0;
 184         if (cp->sync_key_len) {
 185                 pvr2_trace(PVR2_TRACE_DATA_FLOW,
 186                            "/*---TRACE_READ---*/ sync_state <== 1");
 187                 cp->sync_state = 1;
 188                 cp->sync_trashed_count = 0;
 189                 cp->sync_buf_offs = 0;
 190         }
 191         cp->spigot_open = 0;
 192         return 0;
 193 }
 194
 195 struct pvr2_stream *pvr2_ioread_get_stream(struct pvr2_ioread *cp)
 196 {
 197         return cp->stream;
 198 }
 199
 200 int pvr2_ioread_setup(struct pvr2_ioread *cp,struct pvr2_stream *sp)
 201 {
 202         int ret;
 203         unsigned int idx;
 204         struct pvr2_buffer *bp;
 205
 206         mutex_lock(&cp->mutex);
 207         do {
 208                 if (cp->stream) {
 209                         pvr2_trace(PVR2_TRACE_START_STOP,
 210                                    "/*---TRACE_READ---*/ pvr2_ioread_setup (tear-down) id=%p",
 211                                    cp);
 212                         pvr2_ioread_stop(cp);
 213                         pvr2_stream_kill(cp->stream);
 214                         if (pvr2_stream_get_buffer_count(cp->stream)) {
 215                                 pvr2_stream_set_buffer_count(cp->stream,0);
 216                         }
 217                         cp->stream = NULL;
 218                 }
 219                 if (sp) {
 220                         pvr2_trace(PVR2_TRACE_START_STOP,
 221                                    "/*---TRACE_READ---*/ pvr2_ioread_setup (setup) id=%p",
 222                                    cp);
 223                         pvr2_stream_kill(sp);
 224                         ret = pvr2_stream_set_buffer_count(sp,BUFFER_COUNT);
 225                         if (ret < 0) {
 226                                 mutex_unlock(&cp->mutex);
 227                                 return ret;
 228                         }
 229                         for (idx = 0; idx < BUFFER_COUNT; idx++) {
 230                                 bp = pvr2_stream_get_buffer(sp,idx);
 231                                 pvr2_buffer_set_buffer(bp,
 232                                                        cp->buffer_storage[idx],
 233                                                        BUFFER_SIZE);
 234                         }
 235                         cp->stream = sp;
 236                 }
 237         } while (0);
 238         mutex_unlock(&cp->mutex);
 239
 240         return 0;
 241 }
 242
 243 int pvr2_ioread_set_enabled(struct pvr2_ioread *cp,int fl)
 244 {
 245         int ret = 0;
 246         if ((!fl) == (!(cp->enabled))) return ret;
 247
 248         mutex_lock(&cp->mutex);
 249         do {
 250                 if (fl) {
 251                         ret = pvr2_ioread_start(cp);
 252                 } else {
 253                         pvr2_ioread_stop(cp);
 254                 }
 255         } while (0);
 256         mutex_unlock(&cp->mutex);
 257         return ret;
 258 }
 259
 260 static int pvr2_ioread_get_buffer(struct pvr2_ioread *cp)
 261 {
 262         int stat;
 263
 264         while (cp->c_data_len <= cp->c_data_offs) {
 265                 if (cp->c_buf) {
 266                         // Flush out current buffer first.
 267                         stat = pvr2_buffer_queue(cp->c_buf);
 268                         if (stat < 0) {
 269                                 // Streaming error...
 270                                 pvr2_trace(PVR2_TRACE_DATA_FLOW,
 271                                            "/*---TRACE_READ---*/ pvr2_ioread_read id=%p queue_error=%d",
 272                                            cp,stat);
 273                                 pvr2_ioread_stop(cp);
 274                                 return 0;
 275                         }
 276                         cp->c_buf = NULL;
 277                         cp->c_data_ptr = NULL;
 278                         cp->c_data_len = 0;
 279                         cp->c_data_offs = 0;
 280                 }
 281                 // Now get a freshly filled buffer.
 282                 cp->c_buf = pvr2_stream_get_ready_buffer(cp->stream);
 283                 if (!cp->c_buf) break; // Nothing ready; done.
 284                 cp->c_data_len = pvr2_buffer_get_count(cp->c_buf);
 285                 if (!cp->c_data_len) {
 286                         // Nothing transferred.  Was there an error?
 287                         stat = pvr2_buffer_get_status(cp->c_buf);
 288                         if (stat < 0) {
 289                                 // Streaming error...
 290                                 pvr2_trace(PVR2_TRACE_DATA_FLOW,
 291                                            "/*---TRACE_READ---*/ pvr2_ioread_read id=%p buffer_error=%d",
 292                                            cp,stat);
 293                                 pvr2_ioread_stop(cp);
 294                                 // Give up.
 295                                 return 0;
 296                         }
 297                         // Start over...
 298                         continue;
 299                 }
 300                 cp->c_data_offs = 0;
 301                 cp->c_data_ptr = cp->buffer_storage[
 302                         pvr2_buffer_get_id(cp->c_buf)];
 303         }
 304         return !0;
 305 }
 306
 307 static void pvr2_ioread_filter(struct pvr2_ioread *cp)
 308 {
 309         unsigned int idx;
 310         if (!cp->enabled) return;
 311         if (cp->sync_state != 1) return;
 312
 313         // Search the stream for our synchronization key.  This is made
 314         // complicated by the fact that in order to be honest with
 315         // ourselves here we must search across buffer boundaries...
 316         mutex_lock(&cp->mutex);
 317         while (1) {
 318                 // Ensure we have a buffer
 319                 if (!pvr2_ioread_get_buffer(cp)) break;
 320                 if (!cp->c_data_len) break;
 321
 322                 // Now walk the buffer contents until we match the key or
 323                 // run out of buffer data.
 324                 for (idx = cp->c_data_offs; idx < cp->c_data_len; idx++) {
 325                         if (cp->sync_buf_offs >= cp->sync_key_len) break;
 326                         if (cp->c_data_ptr[idx] ==
 327                             cp->sync_key_ptr[cp->sync_buf_offs]) {
 328                                 // Found the next key byte
 329                                 (cp->sync_buf_offs)++;
 330                         } else {
 331                                 // Whoops, mismatched.  Start key over...
 332                                 cp->sync_buf_offs = 0;
 333                         }
 334                 }
 335
 336                 // Consume what we've walked through
 337                 cp->c_data_offs += idx;
 338                 cp->sync_trashed_count += idx;
 339
 340                 // If we've found the key, then update state and get out.
 341                 if (cp->sync_buf_offs >= cp->sync_key_len) {
 342                         cp->sync_trashed_count -= cp->sync_key_len;
 343                         pvr2_trace(PVR2_TRACE_DATA_FLOW,
 344                                    "/*---TRACE_READ---*/ sync_state <== 2 (skipped %u bytes)",
 345                                    cp->sync_trashed_count);
 346                         cp->sync_state = 2;
 347                         cp->sync_buf_offs = 0;
 348                         break;
 349                 }
 350
 351                 if (cp->c_data_offs < cp->c_data_len) {
 352                         // Sanity check - should NEVER get here
 353                         pvr2_trace(PVR2_TRACE_ERROR_LEGS,
 354                                    "ERROR: pvr2_ioread filter sync problem len=%u offs=%u",
 355                                    cp->c_data_len,cp->c_data_offs);
 356                         // Get out so we don't get stuck in an infinite
 357                         // loop.
 358                         break;
 359                 }
 360
 361                 continue; // (for clarity)
 362         }
 363         mutex_unlock(&cp->mutex);
 364 }
 365
 366 int pvr2_ioread_avail(struct pvr2_ioread *cp)
 367 {
 368         int ret;
 369         if (!(cp->enabled)) {
 370                 // Stream is not enabled; so this is an I/O error
 371                 return -EIO;
 372         }
 373
 374         if (cp->sync_state == 1) {
 375                 pvr2_ioread_filter(cp);
 376                 if (cp->sync_state == 1) return -EAGAIN;
 377         }
 378
 379         ret = 0;
 380         if (cp->stream_running) {
 381                 if (!pvr2_stream_get_ready_count(cp->stream)) {
 382                         // No data available at all right now.
 383                         ret = -EAGAIN;
 384                 }
 385         } else {
 386                 if (pvr2_stream_get_ready_count(cp->stream) < BUFFER_COUNT/2) {
 387                         // Haven't buffered up enough yet; try again later
 388                         ret = -EAGAIN;
 389                 }
 390         }
 391
 392         if ((!(cp->spigot_open)) != (!(ret == 0))) {
 393                 cp->spigot_open = (ret == 0);
 394                 pvr2_trace(PVR2_TRACE_DATA_FLOW,
 395                            "/*---TRACE_READ---*/ data is %s",
 396                            cp->spigot_open ? "available" : "pending");
 397         }
 398
 399         return ret;
 400 }
 401
 402 int pvr2_ioread_read(struct pvr2_ioread *cp,void __user *buf,unsigned int cnt)
 403 {
 404         unsigned int copied_cnt;
 405         unsigned int bcnt;
 406         const char *src;
 407         int stat;
 408         int ret = 0;
 409         unsigned int req_cnt = cnt;
 410
 411         if (!cnt) {
 412                 pvr2_trace(PVR2_TRACE_TRAP,
 413                            "/*---TRACE_READ---*/ pvr2_ioread_read id=%p ZERO Request? Returning zero.",
 414 cp);
 415                 return 0;
 416         }
 417
 418         stat = pvr2_ioread_avail(cp);
 419         if (stat < 0) return stat;
 420
 421         cp->stream_running = !0;
 422
 423         mutex_lock(&cp->mutex);
 424         do {
 425
 426                 // Suck data out of the buffers and copy to the user
 427                 copied_cnt = 0;
 428                 if (!buf) cnt = 0;
 429                 while (1) {
 430                         if (!pvr2_ioread_get_buffer(cp)) {
 431                                 ret = -EIO;
 432                                 break;
 433                         }
 434
 435                         if (!cnt) break;
 436
 437                         if (cp->sync_state == 2) {
 438                                 // We're repeating the sync key data into
 439                                 // the stream.
 440                                 src = cp->sync_key_ptr + cp->sync_buf_offs;
 441                                 bcnt = cp->sync_key_len - cp->sync_buf_offs;
 442                         } else {
 443                                 // Normal buffer copy
 444                                 src = cp->c_data_ptr + cp->c_data_offs;
 445                                 bcnt = cp->c_data_len - cp->c_data_offs;
 446                         }
 447
 448                         if (!bcnt) break;
 449
 450                         // Don't run past user's buffer
 451                         if (bcnt > cnt) bcnt = cnt;
 452
 453                         if (copy_to_user(buf,src,bcnt)) {
 454                                 // User supplied a bad pointer?
 455                                 // Give up - this *will* cause data
 456                                 // to be lost.
 457                                 ret = -EFAULT;
 458                                 break;
 459                         }
 460                         cnt -= bcnt;
 461                         buf += bcnt;
 462                         copied_cnt += bcnt;
 463
 464                         if (cp->sync_state == 2) {
 465                                 // Update offset inside sync key that we're
 466                                 // repeating back out.
 467                                 cp->sync_buf_offs += bcnt;
 468                                 if (cp->sync_buf_offs >= cp->sync_key_len) {
 469                                         // Consumed entire key; switch mode
 470                                         // to normal.
 471                                         pvr2_trace(PVR2_TRACE_DATA_FLOW,
 472                                                    "/*---TRACE_READ---*/ sync_state <== 0");
 473                                         cp->sync_state = 0;
 474                                 }
 475                         } else {
 476                                 // Update buffer offset.
 477                                 cp->c_data_offs += bcnt;
 478                         }
 479                 }
 480
 481         } while (0);
 482         mutex_unlock(&cp->mutex);
 483
 484         if (!ret) {
 485                 if (copied_cnt) {
 486                         // If anything was copied, return that count
 487                         ret = copied_cnt;
 488                 } else {
 489                         // Nothing copied; suggest to caller that another
 490                         // attempt should be tried again later
 491                         ret = -EAGAIN;
 492                 }
 493         }
 494
 495         pvr2_trace(PVR2_TRACE_DATA_FLOW,
 496                    "/*---TRACE_READ---*/ pvr2_ioread_read id=%p request=%d result=%d",
 497                    cp,req_cnt,ret);
 498         return ret;
 499 }