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 = 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) return ret;
 227                         for (idx = 0; idx < BUFFER_COUNT; idx++) {
 228                                 bp = pvr2_stream_get_buffer(sp,idx);
 229                                 pvr2_buffer_set_buffer(bp,
 230                                                        cp->buffer_storage[idx],
 231                                                        BUFFER_SIZE);
 232                         }
 233                         cp->stream = sp;
 234                 }
 235         } while (0); mutex_unlock(&cp->mutex);
 236
 237         return 0;
 238 }
 239
 240 int pvr2_ioread_set_enabled(struct pvr2_ioread *cp,int fl)
 241 {
 242         int ret = 0;
 243         if ((!fl) == (!(cp->enabled))) return ret;
 244
 245         mutex_lock(&cp->mutex); do {
 246                 if (fl) {
 247                         ret = pvr2_ioread_start(cp);
 248                 } else {
 249                         pvr2_ioread_stop(cp);
 250                 }
 251         } while (0); mutex_unlock(&cp->mutex);
 252         return ret;
 253 }
 254
 255 static int pvr2_ioread_get_buffer(struct pvr2_ioread *cp)
 256 {
 257         int stat;
 258
 259         while (cp->c_data_len <= cp->c_data_offs) {
 260                 if (cp->c_buf) {
 261                         // Flush out current buffer first.
 262                         stat = pvr2_buffer_queue(cp->c_buf);
 263                         if (stat < 0) {
 264                                 // Streaming error...
 265                                 pvr2_trace(PVR2_TRACE_DATA_FLOW,
 266                                            "/*---TRACE_READ---*/"
 267                                            " pvr2_ioread_read id=%p"
 268                                            " queue_error=%d",
 269                                            cp,stat);
 270                                 pvr2_ioread_stop(cp);
 271                                 return 0;
 272                         }
 273                         cp->c_buf = NULL;
 274                         cp->c_data_ptr = NULL;
 275                         cp->c_data_len = 0;
 276                         cp->c_data_offs = 0;
 277                 }
 278                 // Now get a freshly filled buffer.
 279                 cp->c_buf = pvr2_stream_get_ready_buffer(cp->stream);
 280                 if (!cp->c_buf) break; // Nothing ready; done.
 281                 cp->c_data_len = pvr2_buffer_get_count(cp->c_buf);
 282                 if (!cp->c_data_len) {
 283                         // Nothing transferred.  Was there an error?
 284                         stat = pvr2_buffer_get_status(cp->c_buf);
 285                         if (stat < 0) {
 286                                 // Streaming error...
 287                                 pvr2_trace(PVR2_TRACE_DATA_FLOW,
 288                                            "/*---TRACE_READ---*/"
 289                                            " pvr2_ioread_read id=%p"
 290                                            " buffer_error=%d",
 291                                            cp,stat);
 292                                 pvr2_ioread_stop(cp);
 293                                 // Give up.
 294                                 return 0;
 295                         }
 296                         // Start over...
 297                         continue;
 298                 }
 299                 cp->c_data_offs = 0;
 300                 cp->c_data_ptr = cp->buffer_storage[
 301                         pvr2_buffer_get_id(cp->c_buf)];
 302         }
 303         return !0;
 304 }
 305
 306 static void pvr2_ioread_filter(struct pvr2_ioread *cp)
 307 {
 308         unsigned int idx;
 309         if (!cp->enabled) return;
 310         if (cp->sync_state != 1) return;
 311
 312         // Search the stream for our synchronization key.  This is made
 313         // complicated by the fact that in order to be honest with
 314         // ourselves here we must search across buffer boundaries...
 315         mutex_lock(&cp->mutex); while (1) {
 316                 // Ensure we have a buffer
 317                 if (!pvr2_ioread_get_buffer(cp)) break;
 318                 if (!cp->c_data_len) break;
 319
 320                 // Now walk the buffer contents until we match the key or
 321                 // run out of buffer data.
 322                 for (idx = cp->c_data_offs; idx < cp->c_data_len; idx++) {
 323                         if (cp->sync_buf_offs >= cp->sync_key_len) break;
 324                         if (cp->c_data_ptr[idx] ==
 325                             cp->sync_key_ptr[cp->sync_buf_offs]) {
 326                                 // Found the next key byte
 327                                 (cp->sync_buf_offs)++;
 328                         } else {
 329                                 // Whoops, mismatched.  Start key over...
 330                                 cp->sync_buf_offs = 0;
 331                         }
 332                 }
 333
 334                 // Consume what we've walked through
 335                 cp->c_data_offs += idx;
 336                 cp->sync_trashed_count += idx;
 337
 338                 // If we've found the key, then update state and get out.
 339                 if (cp->sync_buf_offs >= cp->sync_key_len) {
 340                         cp->sync_trashed_count -= cp->sync_key_len;
 341                         pvr2_trace(PVR2_TRACE_DATA_FLOW,
 342                                    "/*---TRACE_READ---*/"
 343                                    " sync_state <== 2 (skipped %u bytes)",
 344                                    cp->sync_trashed_count);
 345                         cp->sync_state = 2;
 346                         cp->sync_buf_offs = 0;
 347                         break;
 348                 }
 349
 350                 if (cp->c_data_offs < cp->c_data_len) {
 351                         // Sanity check - should NEVER get here
 352                         pvr2_trace(PVR2_TRACE_ERROR_LEGS,
 353                                    "ERROR: pvr2_ioread filter sync problem"
 354                                    " 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         } mutex_unlock(&cp->mutex);
 363 }
 364
 365 int pvr2_ioread_avail(struct pvr2_ioread *cp)
 366 {
 367         int ret;
 368         if (!(cp->enabled)) {
 369                 // Stream is not enabled; so this is an I/O error
 370                 return -EIO;
 371         }
 372
 373         if (cp->sync_state == 1) {
 374                 pvr2_ioread_filter(cp);
 375                 if (cp->sync_state == 1) return -EAGAIN;
 376         }
 377
 378         ret = 0;
 379         if (cp->stream_running) {
 380                 if (!pvr2_stream_get_ready_count(cp->stream)) {
 381                         // No data available at all right now.
 382                         ret = -EAGAIN;
 383                 }
 384         } else {
 385                 if (pvr2_stream_get_ready_count(cp->stream) < BUFFER_COUNT/2) {
 386                         // Haven't buffered up enough yet; try again later
 387                         ret = -EAGAIN;
 388                 }
 389         }
 390
 391         if ((!(cp->spigot_open)) != (!(ret == 0))) {
 392                 cp->spigot_open = (ret == 0);
 393                 pvr2_trace(PVR2_TRACE_DATA_FLOW,
 394                            "/*---TRACE_READ---*/ data is %s",
 395                            cp->spigot_open ? "available" : "pending");
 396         }
 397
 398         return ret;
 399 }
 400
 401 int pvr2_ioread_read(struct pvr2_ioread *cp,void __user *buf,unsigned int cnt)
 402 {
 403         unsigned int copied_cnt;
 404         unsigned int bcnt;
 405         const char *src;
 406         int stat;
 407         int ret = 0;
 408         unsigned int req_cnt = cnt;
 409
 410         if (!cnt) {
 411                 pvr2_trace(PVR2_TRACE_TRAP,
 412                            "/*---TRACE_READ---*/ pvr2_ioread_read id=%p"
 413                            " ZERO Request? Returning zero.",cp);
 414                 return 0;
 415         }
 416
 417         stat = pvr2_ioread_avail(cp);
 418         if (stat < 0) return stat;
 419
 420         cp->stream_running = !0;
 421
 422         mutex_lock(&cp->mutex); do {
 423
 424                 // Suck data out of the buffers and copy to the user
 425                 copied_cnt = 0;
 426                 if (!buf) cnt = 0;
 427                 while (1) {
 428                         if (!pvr2_ioread_get_buffer(cp)) {
 429                                 ret = -EIO;
 430                                 break;
 431                         }
 432
 433                         if (!cnt) break;
 434
 435                         if (cp->sync_state == 2) {
 436                                 // We're repeating the sync key data into
 437                                 // the stream.
 438                                 src = cp->sync_key_ptr + cp->sync_buf_offs;
 439                                 bcnt = cp->sync_key_len - cp->sync_buf_offs;
 440                         } else {
 441                                 // Normal buffer copy
 442                                 src = cp->c_data_ptr + cp->c_data_offs;
 443                                 bcnt = cp->c_data_len - cp->c_data_offs;
 444                         }
 445
 446                         if (!bcnt) break;
 447
 448                         // Don't run past user's buffer
 449                         if (bcnt > cnt) bcnt = cnt;
 450
 451                         if (copy_to_user(buf,src,bcnt)) {
 452                                 // User supplied a bad pointer?
 453                                 // Give up - this *will* cause data
 454                                 // to be lost.
 455                                 ret = -EFAULT;
 456                                 break;
 457                         }
 458                         cnt -= bcnt;
 459                         buf += bcnt;
 460                         copied_cnt += bcnt;
 461
 462                         if (cp->sync_state == 2) {
 463                                 // Update offset inside sync key that we're
 464                                 // repeating back out.
 465                                 cp->sync_buf_offs += bcnt;
 466                                 if (cp->sync_buf_offs >= cp->sync_key_len) {
 467                                         // Consumed entire key; switch mode
 468                                         // to normal.
 469                                         pvr2_trace(PVR2_TRACE_DATA_FLOW,
 470                                                    "/*---TRACE_READ---*/"
 471                                                    " sync_state <== 0");
 472                                         cp->sync_state = 0;
 473                                 }
 474                         } else {
 475                                 // Update buffer offset.
 476                                 cp->c_data_offs += bcnt;
 477                         }
 478                 }
 479
 480         } while (0); mutex_unlock(&cp->mutex);
 481
 482         if (!ret) {
 483                 if (copied_cnt) {
 484                         // If anything was copied, return that count
 485                         ret = copied_cnt;
 486                 } else {
 487                         // Nothing copied; suggest to caller that another
 488                         // attempt should be tried again later
 489                         ret = -EAGAIN;
 490                 }
 491         }
 492
 493         pvr2_trace(PVR2_TRACE_DATA_FLOW,
 494                    "/*---TRACE_READ---*/ pvr2_ioread_read"
 495                    " id=%p request=%d result=%d",
 496                    cp,req_cnt,ret);
 497         return ret;
 498 }
 499
 500
 501 /*
 502   Stuff for Emacs to see, in order to encourage consistent editing style:
 503   *** Local Variables: ***
 504   *** mode: c ***
 505   *** fill-column: 75 ***
 506   *** tab-width: 8 ***
 507   *** c-basic-offset: 8 ***
 508   *** End: ***
 509   */