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