kernel/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 <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);
 209         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) {
 228                                 mutex_unlock(&cp->mutex);
 229                                 return ret;
 230                         }
 231                         for (idx = 0; idx < BUFFER_COUNT; idx++) {
 232                                 bp = pvr2_stream_get_buffer(sp,idx);
 233                                 pvr2_buffer_set_buffer(bp,
 234                                                        cp->buffer_storage[idx],
 235                                                        BUFFER_SIZE);
 236                         }
 237                         cp->stream = sp;
 238                 }
 239         } while (0);
 240         mutex_unlock(&cp->mutex);
 241
 242         return 0;
 243 }
 244
 245 int pvr2_ioread_set_enabled(struct pvr2_ioread *cp,int fl)
 246 {
 247         int ret = 0;
 248         if ((!fl) == (!(cp->enabled))) return ret;
 249
 250         mutex_lock(&cp->mutex);
 251         do {
 252                 if (fl) {
 253                         ret = pvr2_ioread_start(cp);
 254                 } else {
 255                         pvr2_ioread_stop(cp);
 256                 }
 257         } while (0);
 258         mutex_unlock(&cp->mutex);
 259         return ret;
 260 }
 261
 262 static int pvr2_ioread_get_buffer(struct pvr2_ioread *cp)
 263 {
 264         int stat;
 265
 266         while (cp->c_data_len <= cp->c_data_offs) {
 267                 if (cp->c_buf) {
 268                         // Flush out current buffer first.
 269                         stat = pvr2_buffer_queue(cp->c_buf);
 270                         if (stat < 0) {
 271                                 // Streaming error...
 272                                 pvr2_trace(PVR2_TRACE_DATA_FLOW,
 273                                            "/*---TRACE_READ---*/"
 274                                            " pvr2_ioread_read id=%p"
 275                                            " queue_error=%d",
 276                                            cp,stat);
 277                                 pvr2_ioread_stop(cp);
 278                                 return 0;
 279                         }
 280                         cp->c_buf = NULL;
 281                         cp->c_data_ptr = NULL;
 282                         cp->c_data_len = 0;
 283                         cp->c_data_offs = 0;
 284                 }
 285                 // Now get a freshly filled buffer.
 286                 cp->c_buf = pvr2_stream_get_ready_buffer(cp->stream);
 287                 if (!cp->c_buf) break; // Nothing ready; done.
 288                 cp->c_data_len = pvr2_buffer_get_count(cp->c_buf);
 289                 if (!cp->c_data_len) {
 290                         // Nothing transferred.  Was there an error?
 291                         stat = pvr2_buffer_get_status(cp->c_buf);
 292                         if (stat < 0) {
 293                                 // Streaming error...
 294                                 pvr2_trace(PVR2_TRACE_DATA_FLOW,
 295                                            "/*---TRACE_READ---*/"
 296                                            " pvr2_ioread_read id=%p"
 297                                            " buffer_error=%d",
 298                                            cp,stat);
 299                                 pvr2_ioread_stop(cp);
 300                                 // Give up.
 301                                 return 0;
 302                         }
 303                         // Start over...
 304                         continue;
 305                 }
 306                 cp->c_data_offs = 0;
 307                 cp->c_data_ptr = cp->buffer_storage[
 308                         pvr2_buffer_get_id(cp->c_buf)];
 309         }
 310         return !0;
 311 }
 312
 313 static void pvr2_ioread_filter(struct pvr2_ioread *cp)
 314 {
 315         unsigned int idx;
 316         if (!cp->enabled) return;
 317         if (cp->sync_state != 1) return;
 318
 319         // Search the stream for our synchronization key.  This is made
 320         // complicated by the fact that in order to be honest with
 321         // ourselves here we must search across buffer boundaries...
 322         mutex_lock(&cp->mutex);
 323         while (1) {
 324                 // Ensure we have a buffer
 325                 if (!pvr2_ioread_get_buffer(cp)) break;
 326                 if (!cp->c_data_len) break;
 327
 328                 // Now walk the buffer contents until we match the key or
 329                 // run out of buffer data.
 330                 for (idx = cp->c_data_offs; idx < cp->c_data_len; idx++) {
 331                         if (cp->sync_buf_offs >= cp->sync_key_len) break;
 332                         if (cp->c_data_ptr[idx] ==
 333                             cp->sync_key_ptr[cp->sync_buf_offs]) {
 334                                 // Found the next key byte
 335                                 (cp->sync_buf_offs)++;
 336                         } else {
 337                                 // Whoops, mismatched.  Start key over...
 338                                 cp->sync_buf_offs = 0;
 339                         }
 340                 }
 341
 342                 // Consume what we've walked through
 343                 cp->c_data_offs += idx;
 344                 cp->sync_trashed_count += idx;
 345
 346                 // If we've found the key, then update state and get out.
 347                 if (cp->sync_buf_offs >= cp->sync_key_len) {
 348                         cp->sync_trashed_count -= cp->sync_key_len;
 349                         pvr2_trace(PVR2_TRACE_DATA_FLOW,
 350                                    "/*---TRACE_READ---*/"
 351                                    " sync_state <== 2 (skipped %u bytes)",
 352                                    cp->sync_trashed_count);
 353                         cp->sync_state = 2;
 354                         cp->sync_buf_offs = 0;
 355                         break;
 356                 }
 357
 358                 if (cp->c_data_offs < cp->c_data_len) {
 359                         // Sanity check - should NEVER get here
 360                         pvr2_trace(PVR2_TRACE_ERROR_LEGS,
 361                                    "ERROR: pvr2_ioread filter sync problem"
 362                                    " len=%u offs=%u",
 363                                    cp->c_data_len,cp->c_data_offs);
 364                         // Get out so we don't get stuck in an infinite
 365                         // loop.
 366                         break;
 367                 }
 368
 369                 continue; // (for clarity)
 370         }
 371         mutex_unlock(&cp->mutex);
 372 }
 373
 374 int pvr2_ioread_avail(struct pvr2_ioread *cp)
 375 {
 376         int ret;
 377         if (!(cp->enabled)) {
 378                 // Stream is not enabled; so this is an I/O error
 379                 return -EIO;
 380         }
 381
 382         if (cp->sync_state == 1) {
 383                 pvr2_ioread_filter(cp);
 384                 if (cp->sync_state == 1) return -EAGAIN;
 385         }
 386
 387         ret = 0;
 388         if (cp->stream_running) {
 389                 if (!pvr2_stream_get_ready_count(cp->stream)) {
 390                         // No data available at all right now.
 391                         ret = -EAGAIN;
 392                 }
 393         } else {
 394                 if (pvr2_stream_get_ready_count(cp->stream) < BUFFER_COUNT/2) {
 395                         // Haven't buffered up enough yet; try again later
 396                         ret = -EAGAIN;
 397                 }
 398         }
 399
 400         if ((!(cp->spigot_open)) != (!(ret == 0))) {
 401                 cp->spigot_open = (ret == 0);
 402                 pvr2_trace(PVR2_TRACE_DATA_FLOW,
 403                            "/*---TRACE_READ---*/ data is %s",
 404                            cp->spigot_open ? "available" : "pending");
 405         }
 406
 407         return ret;
 408 }
 409
 410 int pvr2_ioread_read(struct pvr2_ioread *cp,void __user *buf,unsigned int cnt)
 411 {
 412         unsigned int copied_cnt;
 413         unsigned int bcnt;
 414         const char *src;
 415         int stat;
 416         int ret = 0;
 417         unsigned int req_cnt = cnt;
 418
 419         if (!cnt) {
 420                 pvr2_trace(PVR2_TRACE_TRAP,
 421                            "/*---TRACE_READ---*/ pvr2_ioread_read id=%p"
 422                            " ZERO Request? Returning zero.",cp);
 423                 return 0;
 424         }
 425
 426         stat = pvr2_ioread_avail(cp);
 427         if (stat < 0) return stat;
 428
 429         cp->stream_running = !0;
 430
 431         mutex_lock(&cp->mutex);
 432         do {
 433
 434                 // Suck data out of the buffers and copy to the user
 435                 copied_cnt = 0;
 436                 if (!buf) cnt = 0;
 437                 while (1) {
 438                         if (!pvr2_ioread_get_buffer(cp)) {
 439                                 ret = -EIO;
 440                                 break;
 441                         }
 442
 443                         if (!cnt) break;
 444
 445                         if (cp->sync_state == 2) {
 446                                 // We're repeating the sync key data into
 447                                 // the stream.
 448                                 src = cp->sync_key_ptr + cp->sync_buf_offs;
 449                                 bcnt = cp->sync_key_len - cp->sync_buf_offs;
 450                         } else {
 451                                 // Normal buffer copy
 452                                 src = cp->c_data_ptr + cp->c_data_offs;
 453                                 bcnt = cp->c_data_len - cp->c_data_offs;
 454                         }
 455
 456                         if (!bcnt) break;
 457
 458                         // Don't run past user's buffer
 459                         if (bcnt > cnt) bcnt = cnt;
 460
 461                         if (copy_to_user(buf,src,bcnt)) {
 462                                 // User supplied a bad pointer?
 463                                 // Give up - this *will* cause data
 464                                 // to be lost.
 465                                 ret = -EFAULT;
 466                                 break;
 467                         }
 468                         cnt -= bcnt;
 469                         buf += bcnt;
 470                         copied_cnt += bcnt;
 471
 472                         if (cp->sync_state == 2) {
 473                                 // Update offset inside sync key that we're
 474                                 // repeating back out.
 475                                 cp->sync_buf_offs += bcnt;
 476                                 if (cp->sync_buf_offs >= cp->sync_key_len) {
 477                                         // Consumed entire key; switch mode
 478                                         // to normal.
 479                                         pvr2_trace(PVR2_TRACE_DATA_FLOW,
 480                                                    "/*---TRACE_READ---*/"
 481                                                    " sync_state <== 0");
 482                                         cp->sync_state = 0;
 483                                 }
 484                         } else {
 485                                 // Update buffer offset.
 486                                 cp->c_data_offs += bcnt;
 487                         }
 488                 }
 489
 490         } while (0);
 491         mutex_unlock(&cp->mutex);
 492
 493         if (!ret) {
 494                 if (copied_cnt) {
 495                         // If anything was copied, return that count
 496                         ret = copied_cnt;
 497                 } else {
 498                         // Nothing copied; suggest to caller that another
 499                         // attempt should be tried again later
 500                         ret = -EAGAIN;
 501                 }
 502         }
 503
 504         pvr2_trace(PVR2_TRACE_DATA_FLOW,
 505                    "/*---TRACE_READ---*/ pvr2_ioread_read"
 506                    " id=%p request=%d result=%d",
 507                    cp,req_cnt,ret);
 508         return ret;
 509 }