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

   1 /*
   2  *
   3  *  $Id$
   4  *
   5  *  Copyright (C) 2005 Mike Isely <isely@pobox.com>
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License as published by
   9  *  the Free Software Foundation; either version 2 of the License
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  *
  20  */
  21
  22 #include "pvrusb2-ioread.h"
  23 #include "pvrusb2-debug.h"
  24 #include <linux/errno.h>
  25 #include <linux/string.h>
  26 #include <linux/slab.h>
  27 #include <linux/mutex.h>
  28 #include <asm/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 = kmalloc(sizeof(*cp),GFP_KERNEL);
  91         if (!cp) return NULL;
  92         pvr2_trace(PVR2_TRACE_STRUCT,"pvr2_ioread_create id=%p",cp);
  93         memset(cp,0,sizeof(*cp));
  94         if (pvr2_ioread_init(cp) < 0) {
  95                 kfree(cp);
  96                 return NULL;
  97         }
  98         return cp;
  99 }
 100
 101 void pvr2_ioread_destroy(struct pvr2_ioread *cp)
 102 {
 103         if (!cp) return;
 104         pvr2_ioread_done(cp);
 105         pvr2_trace(PVR2_TRACE_STRUCT,"pvr2_ioread_destroy id=%p",cp);
 106         if (cp->sync_key_ptr) {
 107                 kfree(cp->sync_key_ptr);
 108                 cp->sync_key_ptr = NULL;
 109         }
 110         kfree(cp);
 111 }
 112
 113 void pvr2_ioread_set_sync_key(struct pvr2_ioread *cp,
 114                               const char *sync_key_ptr,
 115                               unsigned int sync_key_len)
 116 {
 117         if (!cp) return;
 118
 119         if (!sync_key_ptr) sync_key_len = 0;
 120         if ((sync_key_len == cp->sync_key_len) &&
 121             ((!sync_key_len) ||
 122              (!memcmp(sync_key_ptr,cp->sync_key_ptr,sync_key_len)))) return;
 123
 124         if (sync_key_len != cp->sync_key_len) {
 125                 if (cp->sync_key_ptr) {
 126                         kfree(cp->sync_key_ptr);
 127                         cp->sync_key_ptr = NULL;
 128                 }
 129                 cp->sync_key_len = 0;
 130                 if (sync_key_len) {
 131                         cp->sync_key_ptr = kmalloc(sync_key_len,GFP_KERNEL);
 132                         if (cp->sync_key_ptr) {
 133                                 cp->sync_key_len = sync_key_len;
 134                         }
 135                 }
 136         }
 137         if (!cp->sync_key_len) return;
 138         memcpy(cp->sync_key_ptr,sync_key_ptr,cp->sync_key_len);
 139 }
 140
 141 static void pvr2_ioread_stop(struct pvr2_ioread *cp)
 142 {
 143         if (!(cp->enabled)) return;
 144         pvr2_trace(PVR2_TRACE_START_STOP,
 145                    "/*---TRACE_READ---*/ pvr2_ioread_stop id=%p",cp);
 146         pvr2_stream_kill(cp->stream);
 147         cp->c_buf = NULL;
 148         cp->c_data_ptr = NULL;
 149         cp->c_data_len = 0;
 150         cp->c_data_offs = 0;
 151         cp->enabled = 0;
 152         cp->stream_running = 0;
 153         cp->spigot_open = 0;
 154         if (cp->sync_state) {
 155                 pvr2_trace(PVR2_TRACE_DATA_FLOW,
 156                            "/*---TRACE_READ---*/ sync_state <== 0");
 157                 cp->sync_state = 0;
 158         }
 159 }
 160
 161 static int pvr2_ioread_start(struct pvr2_ioread *cp)
 162 {
 163         int stat;
 164         struct pvr2_buffer *bp;
 165         if (cp->enabled) return 0;
 166         if (!(cp->stream)) return 0;
 167         pvr2_trace(PVR2_TRACE_START_STOP,
 168                    "/*---TRACE_READ---*/ pvr2_ioread_start id=%p",cp);
 169         while ((bp = pvr2_stream_get_idle_buffer(cp->stream)) != 0) {
 170                 stat = pvr2_buffer_queue(bp);
 171                 if (stat < 0) {
 172                         pvr2_trace(PVR2_TRACE_DATA_FLOW,
 173                                    "/*---TRACE_READ---*/"
 174                                    " pvr2_ioread_start id=%p"
 175                                    " error=%d",
 176                                    cp,stat);
 177                         pvr2_ioread_stop(cp);
 178                         return stat;
 179                 }
 180         }
 181         cp->enabled = !0;
 182         cp->c_buf = NULL;
 183         cp->c_data_ptr = NULL;
 184         cp->c_data_len = 0;
 185         cp->c_data_offs = 0;
 186         cp->stream_running = 0;
 187         if (cp->sync_key_len) {
 188                 pvr2_trace(PVR2_TRACE_DATA_FLOW,
 189                            "/*---TRACE_READ---*/ sync_state <== 1");
 190                 cp->sync_state = 1;
 191                 cp->sync_trashed_count = 0;
 192                 cp->sync_buf_offs = 0;
 193         }
 194         cp->spigot_open = 0;
 195         return 0;
 196 }
 197
 198 struct pvr2_stream *pvr2_ioread_get_stream(struct pvr2_ioread *cp)
 199 {
 200         return cp->stream;
 201 }
 202
 203 int pvr2_ioread_setup(struct pvr2_ioread *cp,struct pvr2_stream *sp)
 204 {
 205         int ret;
 206         unsigned int idx;
 207         struct pvr2_buffer *bp;
 208
 209         mutex_lock(&cp->mutex); do {
 210                 if (cp->stream) {
 211                         pvr2_trace(PVR2_TRACE_START_STOP,
 212                                    "/*---TRACE_READ---*/"
 213                                    " pvr2_ioread_setup (tear-down) id=%p",cp);
 214                         pvr2_ioread_stop(cp);
 215                         pvr2_stream_kill(cp->stream);
 216                         if (pvr2_stream_get_buffer_count(cp->stream)) {
 217                                 pvr2_stream_set_buffer_count(cp->stream,0);
 218                         }
 219                         cp->stream = NULL;
 220                 }
 221                 if (sp) {
 222                         pvr2_trace(PVR2_TRACE_START_STOP,
 223                                    "/*---TRACE_READ---*/"
 224                                    " pvr2_ioread_setup (setup) id=%p",cp);
 225                         pvr2_stream_kill(sp);
 226                         ret = pvr2_stream_set_buffer_count(sp,BUFFER_COUNT);
 227                         if (ret < 0) return ret;
 228                         for (idx = 0; idx < BUFFER_COUNT; idx++) {
 229                                 bp = pvr2_stream_get_buffer(sp,idx);
 230                                 pvr2_buffer_set_buffer(bp,
 231                                                        cp->buffer_storage[idx],
 232                                                        BUFFER_SIZE);
 233                         }
 234                         cp->stream = sp;
 235                 }
 236         } while (0); mutex_unlock(&cp->mutex);
 237
 238         return 0;
 239 }
 240
 241 int pvr2_ioread_set_enabled(struct pvr2_ioread *cp,int fl)
 242 {
 243         int ret = 0;
 244         if ((!fl) == (!(cp->enabled))) return ret;
 245
 246         mutex_lock(&cp->mutex); do {
 247                 if (fl) {
 248                         ret = pvr2_ioread_start(cp);
 249                 } else {
 250                         pvr2_ioread_stop(cp);
 251                 }
 252         } while (0); 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---*/"
 268                                            " pvr2_ioread_read id=%p"
 269                                            " queue_error=%d",
 270                                            cp,stat);
 271                                 pvr2_ioread_stop(cp);
 272                                 return 0;
 273                         }
 274                         cp->c_buf = NULL;
 275                         cp->c_data_ptr = NULL;
 276                         cp->c_data_len = 0;
 277                         cp->c_data_offs = 0;
 278                 }
 279                 // Now get a freshly filled buffer.
 280                 cp->c_buf = pvr2_stream_get_ready_buffer(cp->stream);
 281                 if (!cp->c_buf) break; // Nothing ready; done.
 282                 cp->c_data_len = pvr2_buffer_get_count(cp->c_buf);
 283                 if (!cp->c_data_len) {
 284                         // Nothing transferred.  Was there an error?
 285                         stat = pvr2_buffer_get_status(cp->c_buf);
 286                         if (stat < 0) {
 287                                 // Streaming error...
 288                                 pvr2_trace(PVR2_TRACE_DATA_FLOW,
 289                                            "/*---TRACE_READ---*/"
 290                                            " pvr2_ioread_read id=%p"
 291                                            " 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); while (1) {
 317                 // Ensure we have a buffer
 318                 if (!pvr2_ioread_get_buffer(cp)) break;
 319                 if (!cp->c_data_len) break;
 320
 321                 // Now walk the buffer contents until we match the key or
 322                 // run out of buffer data.
 323                 for (idx = cp->c_data_offs; idx < cp->c_data_len; idx++) {
 324                         if (cp->sync_buf_offs >= cp->sync_key_len) break;
 325                         if (cp->c_data_ptr[idx] ==
 326                             cp->sync_key_ptr[cp->sync_buf_offs]) {
 327                                 // Found the next key byte
 328                                 (cp->sync_buf_offs)++;
 329                         } else {
 330                                 // Whoops, mismatched.  Start key over...
 331                                 cp->sync_buf_offs = 0;
 332                         }
 333                 }
 334
 335                 // Consume what we've walked through
 336                 cp->c_data_offs += idx;
 337                 cp->sync_trashed_count += idx;
 338
 339                 // If we've found the key, then update state and get out.
 340                 if (cp->sync_buf_offs >= cp->sync_key_len) {
 341                         cp->sync_trashed_count -= cp->sync_key_len;
 342                         pvr2_trace(PVR2_TRACE_DATA_FLOW,
 343                                    "/*---TRACE_READ---*/"
 344                                    " 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"
 355                                    " len=%u offs=%u",
 356                                    cp->c_data_len,cp->c_data_offs);
 357                         // Get out so we don't get stuck in an infinite
 358                         // loop.
 359                         break;
 360                 }
 361
 362                 continue; // (for clarity)
 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"
 414                            " ZERO Request? Returning zero.",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); do {
 424
 425                 // Suck data out of the buffers and copy to the user
 426                 copied_cnt = 0;
 427                 if (!buf) cnt = 0;
 428                 while (1) {
 429                         if (!pvr2_ioread_get_buffer(cp)) {
 430                                 ret = -EIO;
 431                                 break;
 432                         }
 433
 434                         if (!cnt) break;
 435
 436                         if (cp->sync_state == 2) {
 437                                 // We're repeating the sync key data into
 438                                 // the stream.
 439                                 src = cp->sync_key_ptr + cp->sync_buf_offs;
 440                                 bcnt = cp->sync_key_len - cp->sync_buf_offs;
 441                         } else {
 442                                 // Normal buffer copy
 443                                 src = cp->c_data_ptr + cp->c_data_offs;
 444                                 bcnt = cp->c_data_len - cp->c_data_offs;
 445                         }
 446
 447                         if (!bcnt) break;
 448
 449                         // Don't run past user's buffer
 450                         if (bcnt > cnt) bcnt = cnt;
 451
 452                         if (copy_to_user(buf,src,bcnt)) {
 453                                 // User supplied a bad pointer?
 454                                 // Give up - this *will* cause data
 455                                 // to be lost.
 456                                 ret = -EFAULT;
 457                                 break;
 458                         }
 459                         cnt -= bcnt;
 460                         buf += bcnt;
 461                         copied_cnt += bcnt;
 462
 463                         if (cp->sync_state == 2) {
 464                                 // Update offset inside sync key that we're
 465                                 // repeating back out.
 466                                 cp->sync_buf_offs += bcnt;
 467                                 if (cp->sync_buf_offs >= cp->sync_key_len) {
 468                                         // Consumed entire key; switch mode
 469                                         // to normal.
 470                                         pvr2_trace(PVR2_TRACE_DATA_FLOW,
 471                                                    "/*---TRACE_READ---*/"
 472                                                    " 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); mutex_unlock(&cp->mutex);
 482
 483         if (!ret) {
 484                 if (copied_cnt) {
 485                         // If anything was copied, return that count
 486                         ret = copied_cnt;
 487                 } else {
 488                         // Nothing copied; suggest to caller that another
 489                         // attempt should be tried again later
 490                         ret = -EAGAIN;
 491                 }
 492         }
 493
 494         pvr2_trace(PVR2_TRACE_DATA_FLOW,
 495                    "/*---TRACE_READ---*/ pvr2_ioread_read"
 496                    " id=%p request=%d result=%d",
 497                    cp,req_cnt,ret);
 498         return ret;
 499 }
 500
 501
 502 /*
 503   Stuff for Emacs to see, in order to encourage consistent editing style:
 504   *** Local Variables: ***
 505   *** mode: c ***
 506   *** fill-column: 75 ***
 507   *** tab-width: 8 ***
 508   *** c-basic-offset: 8 ***
 509   *** End: ***
 510   */