drivers/media/video/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 <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 = 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---*/"
 173                                    " pvr2_ioread_start id=%p"
 174                                    " error=%d",
 175                                    cp,stat);
 176                         pvr2_ioread_stop(cp);
 177                         return stat;
 178                 }
 179         }
 180         cp->enabled = !0;
 181         cp->c_buf = NULL;
 182         cp->c_data_ptr = NULL;
 183         cp->c_data_len = 0;
 184         cp->c_data_offs = 0;
 185         cp->stream_running = 0;
 186         if (cp->sync_key_len) {
 187                 pvr2_trace(PVR2_TRACE_DATA_FLOW,
 188                            "/*---TRACE_READ---*/ sync_state <== 1");
 189                 cp->sync_state = 1;
 190                 cp->sync_trashed_count = 0;
 191                 cp->sync_buf_offs = 0;
 192         }
 193         cp->spigot_open = 0;
 194         return 0;
 195 }
 196
 197 struct pvr2_stream *pvr2_ioread_get_stream(struct pvr2_ioread *cp)
 198 {
 199         return cp->stream;
 200 }
 201
 202 int pvr2_ioread_setup(struct pvr2_ioread *cp,struct pvr2_stream *sp)
 203 {
 204         int ret;
 205         unsigned int idx;
 206         struct pvr2_buffer *bp;
 207
 208         mutex_lock(&cp->mutex); do {
 209                 if (cp->stream) {
 210                         pvr2_trace(PVR2_TRACE_START_STOP,
 211                                    "/*---TRACE_READ---*/"
 212                                    " pvr2_ioread_setup (tear-down) id=%p",cp);
 213                         pvr2_ioread_stop(cp);
 214                         pvr2_stream_kill(cp->stream);
 215                         if (pvr2_stream_get_buffer_count(cp->stream)) {
 216                                 pvr2_stream_set_buffer_count(cp->stream,0);
 217                         }
 218                         cp->stream = NULL;
 219                 }
 220                 if (sp) {
 221                         pvr2_trace(PVR2_TRACE_START_STOP,
 222                                    "/*---TRACE_READ---*/"
 223                                    " pvr2_ioread_setup (setup) id=%p",cp);
 224                         pvr2_stream_kill(sp);
 225                         ret = pvr2_stream_set_buffer_count(sp,BUFFER_COUNT);
 226                         if (ret < 0) {
 227                                 mutex_unlock(&cp->mutex);
 228                                 return ret;
 229                         }
 230                         for (idx = 0; idx < BUFFER_COUNT; idx++) {
 231                                 bp = pvr2_stream_get_buffer(sp,idx);
 232                                 pvr2_buffer_set_buffer(bp,
 233                                                        cp->buffer_storage[idx],
 234                                                        BUFFER_SIZE);
 235                         }
 236                         cp->stream = sp;
 237                 }
 238         } while (0); 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); do {
 249                 if (fl) {
 250                         ret = pvr2_ioread_start(cp);
 251                 } else {
 252                         pvr2_ioread_stop(cp);
 253                 }
 254         } while (0); mutex_unlock(&cp->mutex);
 255         return ret;
 256 }
 257
 258 static int pvr2_ioread_get_buffer(struct pvr2_ioread *cp)
 259 {
 260         int stat;
 261
 262         while (cp->c_data_len <= cp->c_data_offs) {
 263                 if (cp->c_buf) {
 264                         // Flush out current buffer first.
 265                         stat = pvr2_buffer_queue(cp->c_buf);
 266                         if (stat < 0) {
 267                                 // Streaming error...
 268                                 pvr2_trace(PVR2_TRACE_DATA_FLOW,
 269                                            "/*---TRACE_READ---*/"
 270                                            " pvr2_ioread_read id=%p"
 271                                            " 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---*/"
 292                                            " pvr2_ioread_read id=%p"
 293                                            " buffer_error=%d",
 294                                            cp,stat);
 295                                 pvr2_ioread_stop(cp);
 296                                 // Give up.
 297                                 return 0;
 298                         }
 299                         // Start over...
 300                         continue;
 301                 }
 302                 cp->c_data_offs = 0;
 303                 cp->c_data_ptr = cp->buffer_storage[
 304                         pvr2_buffer_get_id(cp->c_buf)];
 305         }
 306         return !0;
 307 }
 308
 309 static void pvr2_ioread_filter(struct pvr2_ioread *cp)
 310 {
 311         unsigned int idx;
 312         if (!cp->enabled) return;
 313         if (cp->sync_state != 1) return;
 314
 315         // Search the stream for our synchronization key.  This is made
 316         // complicated by the fact that in order to be honest with
 317         // ourselves here we must search across buffer boundaries...
 318         mutex_lock(&cp->mutex); while (1) {
 319                 // Ensure we have a buffer
 320                 if (!pvr2_ioread_get_buffer(cp)) break;
 321                 if (!cp->c_data_len) break;
 322
 323                 // Now walk the buffer contents until we match the key or
 324                 // run out of buffer data.
 325                 for (idx = cp->c_data_offs; idx < cp->c_data_len; idx++) {
 326                         if (cp->sync_buf_offs >= cp->sync_key_len) break;
 327                         if (cp->c_data_ptr[idx] ==
 328                             cp->sync_key_ptr[cp->sync_buf_offs]) {
 329                                 // Found the next key byte
 330                                 (cp->sync_buf_offs)++;
 331                         } else {
 332                                 // Whoops, mismatched.  Start key over...
 333                                 cp->sync_buf_offs = 0;
 334                         }
 335                 }
 336
 337                 // Consume what we've walked through
 338                 cp->c_data_offs += idx;
 339                 cp->sync_trashed_count += idx;
 340
 341                 // If we've found the key, then update state and get out.
 342                 if (cp->sync_buf_offs >= cp->sync_key_len) {
 343                         cp->sync_trashed_count -= cp->sync_key_len;
 344                         pvr2_trace(PVR2_TRACE_DATA_FLOW,
 345                                    "/*---TRACE_READ---*/"
 346                                    " sync_state <== 2 (skipped %u bytes)",
 347                                    cp->sync_trashed_count);
 348                         cp->sync_state = 2;
 349                         cp->sync_buf_offs = 0;
 350                         break;
 351                 }
 352
 353                 if (cp->c_data_offs < cp->c_data_len) {
 354                         // Sanity check - should NEVER get here
 355                         pvr2_trace(PVR2_TRACE_ERROR_LEGS,
 356                                    "ERROR: pvr2_ioread filter sync problem"
 357                                    " len=%u offs=%u",
 358                                    cp->c_data_len,cp->c_data_offs);
 359                         // Get out so we don't get stuck in an infinite
 360                         // loop.
 361                         break;
 362                 }
 363
 364                 continue; // (for clarity)
 365         } mutex_unlock(&cp->mutex);
 366 }
 367
 368 int pvr2_ioread_avail(struct pvr2_ioread *cp)
 369 {
 370         int ret;
 371         if (!(cp->enabled)) {
 372                 // Stream is not enabled; so this is an I/O error
 373                 return -EIO;
 374         }
 375
 376         if (cp->sync_state == 1) {
 377                 pvr2_ioread_filter(cp);
 378                 if (cp->sync_state == 1) return -EAGAIN;
 379         }
 380
 381         ret = 0;
 382         if (cp->stream_running) {
 383                 if (!pvr2_stream_get_ready_count(cp->stream)) {
 384                         // No data available at all right now.
 385                         ret = -EAGAIN;
 386                 }
 387         } else {
 388                 if (pvr2_stream_get_ready_count(cp->stream) < BUFFER_COUNT/2) {
 389                         // Haven't buffered up enough yet; try again later
 390                         ret = -EAGAIN;
 391                 }
 392         }
 393
 394         if ((!(cp->spigot_open)) != (!(ret == 0))) {
 395                 cp->spigot_open = (ret == 0);
 396                 pvr2_trace(PVR2_TRACE_DATA_FLOW,
 397                            "/*---TRACE_READ---*/ data is %s",
 398                            cp->spigot_open ? "available" : "pending");
 399         }
 400
 401         return ret;
 402 }
 403
 404 int pvr2_ioread_read(struct pvr2_ioread *cp,void __user *buf,unsigned int cnt)
 405 {
 406         unsigned int copied_cnt;
 407         unsigned int bcnt;
 408         const char *src;
 409         int stat;
 410         int ret = 0;
 411         unsigned int req_cnt = cnt;
 412
 413         if (!cnt) {
 414                 pvr2_trace(PVR2_TRACE_TRAP,
 415                            "/*---TRACE_READ---*/ pvr2_ioread_read id=%p"
 416                            " ZERO Request? Returning zero.",cp);
 417                 return 0;
 418         }
 419
 420         stat = pvr2_ioread_avail(cp);
 421         if (stat < 0) return stat;
 422
 423         cp->stream_running = !0;
 424
 425         mutex_lock(&cp->mutex); do {
 426
 427                 // Suck data out of the buffers and copy to the user
 428                 copied_cnt = 0;
 429                 if (!buf) cnt = 0;
 430                 while (1) {
 431                         if (!pvr2_ioread_get_buffer(cp)) {
 432                                 ret = -EIO;
 433                                 break;
 434                         }
 435
 436                         if (!cnt) break;
 437
 438                         if (cp->sync_state == 2) {
 439                                 // We're repeating the sync key data into
 440                                 // the stream.
 441                                 src = cp->sync_key_ptr + cp->sync_buf_offs;
 442                                 bcnt = cp->sync_key_len - cp->sync_buf_offs;
 443                         } else {
 444                                 // Normal buffer copy
 445                                 src = cp->c_data_ptr + cp->c_data_offs;
 446                                 bcnt = cp->c_data_len - cp->c_data_offs;
 447                         }
 448
 449                         if (!bcnt) break;
 450
 451                         // Don't run past user's buffer
 452                         if (bcnt > cnt) bcnt = cnt;
 453
 454                         if (copy_to_user(buf,src,bcnt)) {
 455                                 // User supplied a bad pointer?
 456                                 // Give up - this *will* cause data
 457                                 // to be lost.
 458                                 ret = -EFAULT;
 459                                 break;
 460                         }
 461                         cnt -= bcnt;
 462                         buf += bcnt;
 463                         copied_cnt += bcnt;
 464
 465                         if (cp->sync_state == 2) {
 466                                 // Update offset inside sync key that we're
 467                                 // repeating back out.
 468                                 cp->sync_buf_offs += bcnt;
 469                                 if (cp->sync_buf_offs >= cp->sync_key_len) {
 470                                         // Consumed entire key; switch mode
 471                                         // to normal.
 472                                         pvr2_trace(PVR2_TRACE_DATA_FLOW,
 473                                                    "/*---TRACE_READ---*/"
 474                                                    " sync_state <== 0");
 475                                         cp->sync_state = 0;
 476                                 }
 477                         } else {
 478                                 // Update buffer offset.
 479                                 cp->c_data_offs += bcnt;
 480                         }
 481                 }
 482
 483         } while (0); mutex_unlock(&cp->mutex);
 484
 485         if (!ret) {
 486                 if (copied_cnt) {
 487                         // If anything was copied, return that count
 488                         ret = copied_cnt;
 489                 } else {
 490                         // Nothing copied; suggest to caller that another
 491                         // attempt should be tried again later
 492                         ret = -EAGAIN;
 493                 }
 494         }
 495
 496         pvr2_trace(PVR2_TRACE_DATA_FLOW,
 497                    "/*---TRACE_READ---*/ pvr2_ioread_read"
 498                    " id=%p request=%d result=%d",
 499                    cp,req_cnt,ret);
 500         return ret;
 501 }
 502
 503
 504 /*
 505   Stuff for Emacs to see, in order to encourage consistent editing style:
 506   *** Local Variables: ***
 507   *** mode: c ***
 508   *** fill-column: 75 ***
 509   *** tab-width: 8 ***
 510   *** c-basic-offset: 8 ***
 511   *** End: ***
 512   */