arch/arm/mach-s3c24xx/dma.c

   1 /*
   2  * Copyright 2003-2006 Simtec Electronics
   3  *      Ben Dooks <ben@simtec.co.uk>
   4  *
   5  * S3C2410 DMA core
   6  *
   7  * http://armlinux.simtec.co.uk/
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12 */
  13
  14
  15 #ifdef CONFIG_S3C2410_DMA_DEBUG
  16 #define DEBUG
  17 #endif
  18
  19 #include <linux/module.h>
  20 #include <linux/init.h>
  21 #include <linux/sched.h>
  22 #include <linux/spinlock.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/syscore_ops.h>
  25 #include <linux/slab.h>
  26 #include <linux/errno.h>
  27 #include <linux/io.h>
  28
  29 #include <asm/irq.h>
  30 #include <mach/hardware.h>
  31 #include <mach/dma.h>
  32 #include <mach/map.h>
  33
  34 #include <plat/dma-s3c24xx.h>
  35 #include <plat/regs-dma.h>
  36
  37 /* io map for dma */
  38 static void __iomem *dma_base;
  39 static struct kmem_cache *dma_kmem;
  40
  41 static int dma_channels;
  42
  43 static struct s3c24xx_dma_selection dma_sel;
  44
  45
  46 /* debugging functions */
  47
  48 #define BUF_MAGIC (0xcafebabe)
  49
  50 #define dmawarn(fmt...) printk(KERN_DEBUG fmt)
  51
  52 #define dma_regaddr(chan, reg) ((chan)->regs + (reg))
  53
  54 #if 1
  55 #define dma_wrreg(chan, reg, val) writel((val), (chan)->regs + (reg))
  56 #else
  57 static inline void
  58 dma_wrreg(struct s3c2410_dma_chan *chan, int reg, unsigned long val)
  59 {
  60         pr_debug("writing %08x to register %08x\n",(unsigned int)val,reg);
  61         writel(val, dma_regaddr(chan, reg));
  62 }
  63 #endif
  64
  65 #define dma_rdreg(chan, reg) readl((chan)->regs + (reg))
  66
  67 /* captured register state for debug */
  68
  69 struct s3c2410_dma_regstate {
  70         unsigned long         dcsrc;
  71         unsigned long         disrc;
  72         unsigned long         dstat;
  73         unsigned long         dcon;
  74         unsigned long         dmsktrig;
  75 };
  76
  77 #ifdef CONFIG_S3C2410_DMA_DEBUG
  78
  79 /* dmadbg_showregs
  80  *
  81  * simple debug routine to print the current state of the dma registers
  82 */
  83
  84 static void
  85 dmadbg_capture(struct s3c2410_dma_chan *chan, struct s3c2410_dma_regstate *regs)
  86 {
  87         regs->dcsrc    = dma_rdreg(chan, S3C2410_DMA_DCSRC);
  88         regs->disrc    = dma_rdreg(chan, S3C2410_DMA_DISRC);
  89         regs->dstat    = dma_rdreg(chan, S3C2410_DMA_DSTAT);
  90         regs->dcon     = dma_rdreg(chan, S3C2410_DMA_DCON);
  91         regs->dmsktrig = dma_rdreg(chan, S3C2410_DMA_DMASKTRIG);
  92 }
  93
  94 static void
  95 dmadbg_dumpregs(const char *fname, int line, struct s3c2410_dma_chan *chan,
  96                  struct s3c2410_dma_regstate *regs)
  97 {
  98         printk(KERN_DEBUG "dma%d: %s:%d: DCSRC=%08lx, DISRC=%08lx, DSTAT=%08lx DMT=%02lx, DCON=%08lx\n",
  99                chan->number, fname, line,
 100                regs->dcsrc, regs->disrc, regs->dstat, regs->dmsktrig,
 101                regs->dcon);
 102 }
 103
 104 static void
 105 dmadbg_showchan(const char *fname, int line, struct s3c2410_dma_chan *chan)
 106 {
 107         struct s3c2410_dma_regstate state;
 108
 109         dmadbg_capture(chan, &state);
 110
 111         printk(KERN_DEBUG "dma%d: %s:%d: ls=%d, cur=%p, %p %p\n",
 112                chan->number, fname, line, chan->load_state,
 113                chan->curr, chan->next, chan->end);
 114
 115         dmadbg_dumpregs(fname, line, chan, &state);
 116 }
 117
 118 static void
 119 dmadbg_showregs(const char *fname, int line, struct s3c2410_dma_chan *chan)
 120 {
 121         struct s3c2410_dma_regstate state;
 122
 123         dmadbg_capture(chan, &state);
 124         dmadbg_dumpregs(fname, line, chan, &state);
 125 }
 126
 127 #define dbg_showregs(chan) dmadbg_showregs(__func__, __LINE__, (chan))
 128 #define dbg_showchan(chan) dmadbg_showchan(__func__, __LINE__, (chan))
 129 #else
 130 #define dbg_showregs(chan) do { } while(0)
 131 #define dbg_showchan(chan) do { } while(0)
 132 #endif /* CONFIG_S3C2410_DMA_DEBUG */
 133
 134 /* s3c2410_dma_stats_timeout
 135  *
 136  * Update DMA stats from timeout info
 137 */
 138
 139 static void
 140 s3c2410_dma_stats_timeout(struct s3c2410_dma_stats *stats, int val)
 141 {
 142         if (stats == NULL)
 143                 return;
 144
 145         if (val > stats->timeout_longest)
 146                 stats->timeout_longest = val;
 147         if (val < stats->timeout_shortest)
 148                 stats->timeout_shortest = val;
 149
 150         stats->timeout_avg += val;
 151 }
 152
 153 /* s3c2410_dma_waitforload
 154  *
 155  * wait for the DMA engine to load a buffer, and update the state accordingly
 156 */
 157
 158 static int
 159 s3c2410_dma_waitforload(struct s3c2410_dma_chan *chan, int line)
 160 {
 161         int timeout = chan->load_timeout;
 162         int took;
 163
 164         if (chan->load_state != S3C2410_DMALOAD_1LOADED) {
 165                 printk(KERN_ERR "dma%d: s3c2410_dma_waitforload() called in loadstate %d from line %d\n", chan->number, chan->load_state, line);
 166                 return 0;
 167         }
 168
 169         if (chan->stats != NULL)
 170                 chan->stats->loads++;
 171
 172         while (--timeout > 0) {
 173                 if ((dma_rdreg(chan, S3C2410_DMA_DSTAT) << (32-20)) != 0) {
 174                         took = chan->load_timeout - timeout;
 175
 176                         s3c2410_dma_stats_timeout(chan->stats, took);
 177
 178                         switch (chan->load_state) {
 179                         case S3C2410_DMALOAD_1LOADED:
 180                                 chan->load_state = S3C2410_DMALOAD_1RUNNING;
 181                                 break;
 182
 183                         default:
 184                                 printk(KERN_ERR "dma%d: unknown load_state in s3c2410_dma_waitforload() %d\n", chan->number, chan->load_state);
 185                         }
 186
 187                         return 1;
 188                 }
 189         }
 190
 191         if (chan->stats != NULL) {
 192                 chan->stats->timeout_failed++;
 193         }
 194
 195         return 0;
 196 }
 197
 198 /* s3c2410_dma_loadbuffer
 199  *
 200  * load a buffer, and update the channel state
 201 */
 202
 203 static inline int
 204 s3c2410_dma_loadbuffer(struct s3c2410_dma_chan *chan,
 205                        struct s3c2410_dma_buf *buf)
 206 {
 207         unsigned long reload;
 208
 209         if (buf == NULL) {
 210                 dmawarn("buffer is NULL\n");
 211                 return -EINVAL;
 212         }
 213
 214         pr_debug("s3c2410_chan_loadbuffer: loading buff %p (0x%08lx,0x%06x)\n",
 215                  buf, (unsigned long)buf->data, buf->size);
 216
 217         /* check the state of the channel before we do anything */
 218
 219         if (chan->load_state == S3C2410_DMALOAD_1LOADED) {
 220                 dmawarn("load_state is S3C2410_DMALOAD_1LOADED\n");
 221         }
 222
 223         if (chan->load_state == S3C2410_DMALOAD_1LOADED_1RUNNING) {
 224                 dmawarn("state is S3C2410_DMALOAD_1LOADED_1RUNNING\n");
 225         }
 226
 227         /* it would seem sensible if we are the last buffer to not bother
 228          * with the auto-reload bit, so that the DMA engine will not try
 229          * and load another transfer after this one has finished...
 230          */
 231         if (chan->load_state == S3C2410_DMALOAD_NONE) {
 232                 pr_debug("load_state is none, checking for noreload (next=%p)\n",
 233                          buf->next);
 234                 reload = (buf->next == NULL) ? S3C2410_DCON_NORELOAD : 0;
 235         } else {
 236                 //pr_debug("load_state is %d => autoreload\n", chan->load_state);
 237                 reload = S3C2410_DCON_AUTORELOAD;
 238         }
 239
 240         if ((buf->data & 0xf0000000) != 0x30000000) {
 241                 dmawarn("dmaload: buffer is %p\n", (void *)buf->data);
 242         }
 243
 244         writel(buf->data, chan->addr_reg);
 245
 246         dma_wrreg(chan, S3C2410_DMA_DCON,
 247                   chan->dcon | reload | (buf->size/chan->xfer_unit));
 248
 249         chan->next = buf->next;
 250
 251         /* update the state of the channel */
 252
 253         switch (chan->load_state) {
 254         case S3C2410_DMALOAD_NONE:
 255                 chan->load_state = S3C2410_DMALOAD_1LOADED;
 256                 break;
 257
 258         case S3C2410_DMALOAD_1RUNNING:
 259                 chan->load_state = S3C2410_DMALOAD_1LOADED_1RUNNING;
 260                 break;
 261
 262         default:
 263                 dmawarn("dmaload: unknown state %d in loadbuffer\n",
 264                         chan->load_state);
 265                 break;
 266         }
 267
 268         return 0;
 269 }
 270
 271 /* s3c2410_dma_call_op
 272  *
 273  * small routine to call the op routine with the given op if it has been
 274  * registered
 275 */
 276
 277 static void
 278 s3c2410_dma_call_op(struct s3c2410_dma_chan *chan, enum s3c2410_chan_op op)
 279 {
 280         if (chan->op_fn != NULL) {
 281                 (chan->op_fn)(chan, op);
 282         }
 283 }
 284
 285 /* s3c2410_dma_buffdone
 286  *
 287  * small wrapper to check if callback routine needs to be called, and
 288  * if so, call it
 289 */
 290
 291 static inline void
 292 s3c2410_dma_buffdone(struct s3c2410_dma_chan *chan, struct s3c2410_dma_buf *buf,
 293                      enum s3c2410_dma_buffresult result)
 294 {
 295 #if 0
 296         pr_debug("callback_fn=%p, buf=%p, id=%p, size=%d, result=%d\n",
 297                  chan->callback_fn, buf, buf->id, buf->size, result);
 298 #endif
 299
 300         if (chan->callback_fn != NULL) {
 301                 (chan->callback_fn)(chan, buf->id, buf->size, result);
 302         }
 303 }
 304
 305 /* s3c2410_dma_start
 306  *
 307  * start a dma channel going
 308 */
 309
 310 static int s3c2410_dma_start(struct s3c2410_dma_chan *chan)
 311 {
 312         unsigned long tmp;
 313         unsigned long flags;
 314
 315         pr_debug("s3c2410_start_dma: channel=%d\n", chan->number);
 316
 317         local_irq_save(flags);
 318
 319         if (chan->state == S3C2410_DMA_RUNNING) {
 320                 pr_debug("s3c2410_start_dma: already running (%d)\n", chan->state);
 321                 local_irq_restore(flags);
 322                 return 0;
 323         }
 324
 325         chan->state = S3C2410_DMA_RUNNING;
 326
 327         /* check whether there is anything to load, and if not, see
 328          * if we can find anything to load
 329          */
 330
 331         if (chan->load_state == S3C2410_DMALOAD_NONE) {
 332                 if (chan->next == NULL) {
 333                         printk(KERN_ERR "dma%d: channel has nothing loaded\n",
 334                                chan->number);
 335                         chan->state = S3C2410_DMA_IDLE;
 336                         local_irq_restore(flags);
 337                         return -EINVAL;
 338                 }
 339
 340                 s3c2410_dma_loadbuffer(chan, chan->next);
 341         }
 342
 343         dbg_showchan(chan);
 344
 345         /* enable the channel */
 346
 347         if (!chan->irq_enabled) {
 348                 enable_irq(chan->irq);
 349                 chan->irq_enabled = 1;
 350         }
 351
 352         /* start the channel going */
 353
 354         tmp = dma_rdreg(chan, S3C2410_DMA_DMASKTRIG);
 355         tmp &= ~S3C2410_DMASKTRIG_STOP;
 356         tmp |= S3C2410_DMASKTRIG_ON;
 357         dma_wrreg(chan, S3C2410_DMA_DMASKTRIG, tmp);
 358
 359         pr_debug("dma%d: %08lx to DMASKTRIG\n", chan->number, tmp);
 360
 361 #if 0
 362         /* the dma buffer loads should take care of clearing the AUTO
 363          * reloading feature */
 364         tmp = dma_rdreg(chan, S3C2410_DMA_DCON);
 365         tmp &= ~S3C2410_DCON_NORELOAD;
 366         dma_wrreg(chan, S3C2410_DMA_DCON, tmp);
 367 #endif
 368
 369         s3c2410_dma_call_op(chan, S3C2410_DMAOP_START);
 370
 371         dbg_showchan(chan);
 372
 373         /* if we've only loaded one buffer onto the channel, then chec
 374          * to see if we have another, and if so, try and load it so when
 375          * the first buffer is finished, the new one will be loaded onto
 376          * the channel */
 377
 378         if (chan->next != NULL) {
 379                 if (chan->load_state == S3C2410_DMALOAD_1LOADED) {
 380
 381                         if (s3c2410_dma_waitforload(chan, __LINE__) == 0) {
 382                                 pr_debug("%s: buff not yet loaded, no more todo\n",
 383                                          __func__);
 384                         } else {
 385                                 chan->load_state = S3C2410_DMALOAD_1RUNNING;
 386                                 s3c2410_dma_loadbuffer(chan, chan->next);
 387                         }
 388
 389                 } else if (chan->load_state == S3C2410_DMALOAD_1RUNNING) {
 390                         s3c2410_dma_loadbuffer(chan, chan->next);
 391                 }
 392         }
 393
 394
 395         local_irq_restore(flags);
 396
 397         return 0;
 398 }
 399
 400 /* s3c2410_dma_canload
 401  *
 402  * work out if we can queue another buffer into the DMA engine
 403 */
 404
 405 static int
 406 s3c2410_dma_canload(struct s3c2410_dma_chan *chan)
 407 {
 408         if (chan->load_state == S3C2410_DMALOAD_NONE ||
 409             chan->load_state == S3C2410_DMALOAD_1RUNNING)
 410                 return 1;
 411
 412         return 0;
 413 }
 414
 415 /* s3c2410_dma_enqueue
 416  *
 417  * queue an given buffer for dma transfer.
 418  *
 419  * id         the device driver's id information for this buffer
 420  * data       the physical address of the buffer data
 421  * size       the size of the buffer in bytes
 422  *
 423  * If the channel is not running, then the flag S3C2410_DMAF_AUTOSTART
 424  * is checked, and if set, the channel is started. If this flag isn't set,
 425  * then an error will be returned.
 426  *
 427  * It is possible to queue more than one DMA buffer onto a channel at
 428  * once, and the code will deal with the re-loading of the next buffer
 429  * when necessary.
 430 */
 431
 432 int s3c2410_dma_enqueue(enum dma_ch channel, void *id,
 433                         dma_addr_t data, int size)
 434 {
 435         struct s3c2410_dma_chan *chan = s3c_dma_lookup_channel(channel);
 436         struct s3c2410_dma_buf *buf;
 437         unsigned long flags;
 438
 439         if (chan == NULL)
 440                 return -EINVAL;
 441
 442         pr_debug("%s: id=%p, data=%08x, size=%d\n",
 443                  __func__, id, (unsigned int)data, size);
 444
 445         buf = kmem_cache_alloc(dma_kmem, GFP_ATOMIC);
 446         if (buf == NULL) {
 447                 pr_debug("%s: out of memory (%ld alloc)\n",
 448                          __func__, (long)sizeof(*buf));
 449                 return -ENOMEM;
 450         }
 451
 452         //pr_debug("%s: new buffer %p\n", __func__, buf);
 453         //dbg_showchan(chan);
 454
 455         buf->next  = NULL;
 456         buf->data  = buf->ptr = data;
 457         buf->size  = size;
 458         buf->id    = id;
 459         buf->magic = BUF_MAGIC;
 460
 461         local_irq_save(flags);
 462
 463         if (chan->curr == NULL) {
 464                 /* we've got nothing loaded... */
 465                 pr_debug("%s: buffer %p queued onto empty channel\n",
 466                          __func__, buf);
 467
 468                 chan->curr = buf;
 469                 chan->end  = buf;
 470                 chan->next = NULL;
 471         } else {
 472                 pr_debug("dma%d: %s: buffer %p queued onto non-empty channel\n",
 473                          chan->number, __func__, buf);
 474
 475                 if (chan->end == NULL) {
 476                         pr_debug("dma%d: %s: %p not empty, and chan->end==NULL?\n",
 477                                  chan->number, __func__, chan);
 478                 } else {
 479                         chan->end->next = buf;
 480                         chan->end = buf;
 481                 }
 482         }
 483
 484         /* if necessary, update the next buffer field */
 485         if (chan->next == NULL)
 486                 chan->next = buf;
 487
 488         /* check to see if we can load a buffer */
 489         if (chan->state == S3C2410_DMA_RUNNING) {
 490                 if (chan->load_state == S3C2410_DMALOAD_1LOADED && 1) {
 491                         if (s3c2410_dma_waitforload(chan, __LINE__) == 0) {
 492                                 printk(KERN_ERR "dma%d: loadbuffer:"
 493                                        "timeout loading buffer\n",
 494                                        chan->number);
 495                                 dbg_showchan(chan);
 496                                 local_irq_restore(flags);
 497                                 return -EINVAL;
 498                         }
 499                 }
 500
 501                 while (s3c2410_dma_canload(chan) && chan->next != NULL) {
 502                         s3c2410_dma_loadbuffer(chan, chan->next);
 503                 }
 504         } else if (chan->state == S3C2410_DMA_IDLE) {
 505                 if (chan->flags & S3C2410_DMAF_AUTOSTART) {
 506                         s3c2410_dma_ctrl(chan->number | DMACH_LOW_LEVEL,
 507                                          S3C2410_DMAOP_START);
 508                 }
 509         }
 510
 511         local_irq_restore(flags);
 512         return 0;
 513 }
 514
 515 EXPORT_SYMBOL(s3c2410_dma_enqueue);
 516
 517 static inline void
 518 s3c2410_dma_freebuf(struct s3c2410_dma_buf *buf)
 519 {
 520         int magicok = (buf->magic == BUF_MAGIC);
 521
 522         buf->magic = -1;
 523
 524         if (magicok) {
 525                 kmem_cache_free(dma_kmem, buf);
 526         } else {
 527                 printk("s3c2410_dma_freebuf: buff %p with bad magic\n", buf);
 528         }
 529 }
 530
 531 /* s3c2410_dma_lastxfer
 532  *
 533  * called when the system is out of buffers, to ensure that the channel
 534  * is prepared for shutdown.
 535 */
 536
 537 static inline void
 538 s3c2410_dma_lastxfer(struct s3c2410_dma_chan *chan)
 539 {
 540 #if 0
 541         pr_debug("dma%d: s3c2410_dma_lastxfer: load_state %d\n",
 542                  chan->number, chan->load_state);
 543 #endif
 544
 545         switch (chan->load_state) {
 546         case S3C2410_DMALOAD_NONE:
 547                 break;
 548
 549         case S3C2410_DMALOAD_1LOADED:
 550                 if (s3c2410_dma_waitforload(chan, __LINE__) == 0) {
 551                                 /* flag error? */
 552                         printk(KERN_ERR "dma%d: timeout waiting for load (%s)\n",
 553                                chan->number, __func__);
 554                         return;
 555                 }
 556                 break;
 557
 558         case S3C2410_DMALOAD_1LOADED_1RUNNING:
 559                 /* I believe in this case we do not have anything to do
 560                  * until the next buffer comes along, and we turn off the
 561                  * reload */
 562                 return;
 563
 564         default:
 565                 pr_debug("dma%d: lastxfer: unhandled load_state %d with no next\n",
 566                          chan->number, chan->load_state);
 567                 return;
 568
 569         }
 570
 571         /* hopefully this'll shut the damned thing up after the transfer... */
 572         dma_wrreg(chan, S3C2410_DMA_DCON, chan->dcon | S3C2410_DCON_NORELOAD);
 573 }
 574
 575
 576 #define dmadbg2(x...)
 577
 578 static irqreturn_t
 579 s3c2410_dma_irq(int irq, void *devpw)
 580 {
 581         struct s3c2410_dma_chan *chan = (struct s3c2410_dma_chan *)devpw;
 582         struct s3c2410_dma_buf  *buf;
 583
 584         buf = chan->curr;
 585
 586         dbg_showchan(chan);
 587
 588         /* modify the channel state */
 589
 590         switch (chan->load_state) {
 591         case S3C2410_DMALOAD_1RUNNING:
 592                 /* TODO - if we are running only one buffer, we probably
 593                  * want to reload here, and then worry about the buffer
 594                  * callback */
 595
 596                 chan->load_state = S3C2410_DMALOAD_NONE;
 597                 break;
 598
 599         case S3C2410_DMALOAD_1LOADED:
 600                 /* iirc, we should go back to NONE loaded here, we
 601                  * had a buffer, and it was never verified as being
 602                  * loaded.
 603                  */
 604
 605                 chan->load_state = S3C2410_DMALOAD_NONE;
 606                 break;
 607
 608         case S3C2410_DMALOAD_1LOADED_1RUNNING:
 609                 /* we'll worry about checking to see if another buffer is
 610                  * ready after we've called back the owner. This should
 611                  * ensure we do not wait around too long for the DMA
 612                  * engine to start the next transfer
 613                  */
 614
 615                 chan->load_state = S3C2410_DMALOAD_1LOADED;
 616                 break;
 617
 618         case S3C2410_DMALOAD_NONE:
 619                 printk(KERN_ERR "dma%d: IRQ with no loaded buffer?\n",
 620                        chan->number);
 621                 break;
 622
 623         default:
 624                 printk(KERN_ERR "dma%d: IRQ in invalid load_state %d\n",
 625                        chan->number, chan->load_state);
 626                 break;
 627         }
 628
 629         if (buf != NULL) {
 630                 /* update the chain to make sure that if we load any more
 631                  * buffers when we call the callback function, things should
 632                  * work properly */
 633
 634                 chan->curr = buf->next;
 635                 buf->next  = NULL;
 636
 637                 if (buf->magic != BUF_MAGIC) {
 638                         printk(KERN_ERR "dma%d: %s: buf %p incorrect magic\n",
 639                                chan->number, __func__, buf);
 640                         return IRQ_HANDLED;
 641                 }
 642
 643                 s3c2410_dma_buffdone(chan, buf, S3C2410_RES_OK);
 644
 645                 /* free resouces */
 646                 s3c2410_dma_freebuf(buf);
 647         } else {
 648         }
 649
 650         /* only reload if the channel is still running... our buffer done
 651          * routine may have altered the state by requesting the dma channel
 652          * to stop or shutdown... */
 653
 654         /* todo: check that when the channel is shut-down from inside this
 655          * function, we cope with unsetting reload, etc */
 656
 657         if (chan->next != NULL && chan->state != S3C2410_DMA_IDLE) {
 658                 unsigned long flags;
 659
 660                 switch (chan->load_state) {
 661                 case S3C2410_DMALOAD_1RUNNING:
 662                         /* don't need to do anything for this state */
 663                         break;
 664
 665                 case S3C2410_DMALOAD_NONE:
 666                         /* can load buffer immediately */
 667                         break;
 668
 669                 case S3C2410_DMALOAD_1LOADED:
 670                         if (s3c2410_dma_waitforload(chan, __LINE__) == 0) {
 671                                 /* flag error? */
 672                                 printk(KERN_ERR "dma%d: timeout waiting for load (%s)\n",
 673                                        chan->number, __func__);
 674                                 return IRQ_HANDLED;
 675                         }
 676
 677                         break;
 678
 679                 case S3C2410_DMALOAD_1LOADED_1RUNNING:
 680                         goto no_load;
 681
 682                 default:
 683                         printk(KERN_ERR "dma%d: unknown load_state in irq, %d\n",
 684                                chan->number, chan->load_state);
 685                         return IRQ_HANDLED;
 686                 }
 687
 688                 local_irq_save(flags);
 689                 s3c2410_dma_loadbuffer(chan, chan->next);
 690                 local_irq_restore(flags);
 691         } else {
 692                 s3c2410_dma_lastxfer(chan);
 693
 694                 /* see if we can stop this channel.. */
 695                 if (chan->load_state == S3C2410_DMALOAD_NONE) {
 696                         pr_debug("dma%d: end of transfer, stopping channel (%ld)\n",
 697                                  chan->number, jiffies);
 698                         s3c2410_dma_ctrl(chan->number | DMACH_LOW_LEVEL,
 699                                          S3C2410_DMAOP_STOP);
 700                 }
 701         }
 702
 703  no_load:
 704         return IRQ_HANDLED;
 705 }
 706
 707 static struct s3c2410_dma_chan *s3c2410_dma_map_channel(int channel);
 708
 709 /* s3c2410_request_dma
 710  *
 711  * get control of an dma channel
 712 */
 713
 714 int s3c2410_dma_request(enum dma_ch channel,
 715                         struct s3c2410_dma_client *client,
 716                         void *dev)
 717 {
 718         struct s3c2410_dma_chan *chan;
 719         unsigned long flags;
 720         int err;
 721
 722         pr_debug("dma%d: s3c2410_request_dma: client=%s, dev=%p\n",
 723                  channel, client->name, dev);
 724
 725         local_irq_save(flags);
 726
 727         chan = s3c2410_dma_map_channel(channel);
 728         if (chan == NULL) {
 729                 local_irq_restore(flags);
 730                 return -EBUSY;
 731         }
 732
 733         dbg_showchan(chan);
 734
 735         chan->client = client;
 736         chan->in_use = 1;
 737
 738         if (!chan->irq_claimed) {
 739                 pr_debug("dma%d: %s : requesting irq %d\n",
 740                          channel, __func__, chan->irq);
 741
 742                 chan->irq_claimed = 1;
 743                 local_irq_restore(flags);
 744
 745                 err = request_irq(chan->irq, s3c2410_dma_irq, IRQF_DISABLED,
 746                                   client->name, (void *)chan);
 747
 748                 local_irq_save(flags);
 749
 750                 if (err) {
 751                         chan->in_use = 0;
 752                         chan->irq_claimed = 0;
 753                         local_irq_restore(flags);
 754
 755                         printk(KERN_ERR "%s: cannot get IRQ %d for DMA %d\n",
 756                                client->name, chan->irq, chan->number);
 757                         return err;
 758                 }
 759
 760                 chan->irq_enabled = 1;
 761         }
 762
 763         local_irq_restore(flags);
 764
 765         /* need to setup */
 766
 767         pr_debug("%s: channel initialised, %p\n", __func__, chan);
 768
 769         return chan->number | DMACH_LOW_LEVEL;
 770 }
 771
 772 EXPORT_SYMBOL(s3c2410_dma_request);
 773
 774 /* s3c2410_dma_free
 775  *
 776  * release the given channel back to the system, will stop and flush
 777  * any outstanding transfers, and ensure the channel is ready for the
 778  * next claimant.
 779  *
 780  * Note, although a warning is currently printed if the freeing client
 781  * info is not the same as the registrant's client info, the free is still
 782  * allowed to go through.
 783 */
 784
 785 int s3c2410_dma_free(enum dma_ch channel, struct s3c2410_dma_client *client)
 786 {
 787         struct s3c2410_dma_chan *chan = s3c_dma_lookup_channel(channel);
 788         unsigned long flags;
 789
 790         if (chan == NULL)
 791                 return -EINVAL;
 792
 793         local_irq_save(flags);
 794
 795         if (chan->client != client) {
 796                 printk(KERN_WARNING "dma%d: possible free from different client (channel %p, passed %p)\n",
 797                        channel, chan->client, client);
 798         }
 799
 800         /* sort out stopping and freeing the channel */
 801
 802         if (chan->state != S3C2410_DMA_IDLE) {
 803                 pr_debug("%s: need to stop dma channel %p\n",
 804                        __func__, chan);
 805
 806                 /* possibly flush the channel */
 807                 s3c2410_dma_ctrl(channel, S3C2410_DMAOP_STOP);
 808         }
 809
 810         chan->client = NULL;
 811         chan->in_use = 0;
 812
 813         if (chan->irq_claimed)
 814                 free_irq(chan->irq, (void *)chan);
 815
 816         chan->irq_claimed = 0;
 817
 818         if (!(channel & DMACH_LOW_LEVEL))
 819                 s3c_dma_chan_map[channel] = NULL;
 820
 821         local_irq_restore(flags);
 822
 823         return 0;
 824 }
 825
 826 EXPORT_SYMBOL(s3c2410_dma_free);
 827
 828 static int s3c2410_dma_dostop(struct s3c2410_dma_chan *chan)
 829 {
 830         unsigned long flags;
 831         unsigned long tmp;
 832
 833         pr_debug("%s:\n", __func__);
 834
 835         dbg_showchan(chan);
 836
 837         local_irq_save(flags);
 838
 839         s3c2410_dma_call_op(chan,  S3C2410_DMAOP_STOP);
 840
 841         tmp = dma_rdreg(chan, S3C2410_DMA_DMASKTRIG);
 842         tmp |= S3C2410_DMASKTRIG_STOP;
 843         //tmp &= ~S3C2410_DMASKTRIG_ON;
 844         dma_wrreg(chan, S3C2410_DMA_DMASKTRIG, tmp);
 845
 846 #if 0
 847         /* should also clear interrupts, according to WinCE BSP */
 848         tmp = dma_rdreg(chan, S3C2410_DMA_DCON);
 849         tmp |= S3C2410_DCON_NORELOAD;
 850         dma_wrreg(chan, S3C2410_DMA_DCON, tmp);
 851 #endif
 852
 853         /* should stop do this, or should we wait for flush? */
 854         chan->state      = S3C2410_DMA_IDLE;
 855         chan->load_state = S3C2410_DMALOAD_NONE;
 856
 857         local_irq_restore(flags);
 858
 859         return 0;
 860 }
 861
 862 static void s3c2410_dma_waitforstop(struct s3c2410_dma_chan *chan)
 863 {
 864         unsigned long tmp;
 865         unsigned int timeout = 0x10000;
 866
 867         while (timeout-- > 0) {
 868                 tmp = dma_rdreg(chan, S3C2410_DMA_DMASKTRIG);
 869
 870                 if (!(tmp & S3C2410_DMASKTRIG_ON))
 871                         return;
 872         }
 873
 874         pr_debug("dma%d: failed to stop?\n", chan->number);
 875 }
 876
 877
 878 /* s3c2410_dma_flush
 879  *
 880  * stop the channel, and remove all current and pending transfers
 881 */
 882
 883 static int s3c2410_dma_flush(struct s3c2410_dma_chan *chan)
 884 {
 885         struct s3c2410_dma_buf *buf, *next;
 886         unsigned long flags;
 887
 888         pr_debug("%s: chan %p (%d)\n", __func__, chan, chan->number);
 889
 890         dbg_showchan(chan);
 891
 892         local_irq_save(flags);
 893
 894         if (chan->state != S3C2410_DMA_IDLE) {
 895                 pr_debug("%s: stopping channel...\n", __func__ );
 896                 s3c2410_dma_ctrl(chan->number, S3C2410_DMAOP_STOP);
 897         }
 898
 899         buf = chan->curr;
 900         if (buf == NULL)
 901                 buf = chan->next;
 902
 903         chan->curr = chan->next = chan->end = NULL;
 904
 905         if (buf != NULL) {
 906                 for ( ; buf != NULL; buf = next) {
 907                         next = buf->next;
 908
 909                         pr_debug("%s: free buffer %p, next %p\n",
 910                                __func__, buf, buf->next);
 911
 912                         s3c2410_dma_buffdone(chan, buf, S3C2410_RES_ABORT);
 913                         s3c2410_dma_freebuf(buf);
 914                 }
 915         }
 916
 917         dbg_showregs(chan);
 918
 919         s3c2410_dma_waitforstop(chan);
 920
 921 #if 0
 922         /* should also clear interrupts, according to WinCE BSP */
 923         {
 924                 unsigned long tmp;
 925
 926                 tmp = dma_rdreg(chan, S3C2410_DMA_DCON);
 927                 tmp |= S3C2410_DCON_NORELOAD;
 928                 dma_wrreg(chan, S3C2410_DMA_DCON, tmp);
 929         }
 930 #endif
 931
 932         dbg_showregs(chan);
 933
 934         local_irq_restore(flags);
 935
 936         return 0;
 937 }
 938
 939 static int s3c2410_dma_started(struct s3c2410_dma_chan *chan)
 940 {
 941         unsigned long flags;
 942
 943         local_irq_save(flags);
 944
 945         dbg_showchan(chan);
 946
 947         /* if we've only loaded one buffer onto the channel, then chec
 948          * to see if we have another, and if so, try and load it so when
 949          * the first buffer is finished, the new one will be loaded onto
 950          * the channel */
 951
 952         if (chan->next != NULL) {
 953                 if (chan->load_state == S3C2410_DMALOAD_1LOADED) {
 954
 955                         if (s3c2410_dma_waitforload(chan, __LINE__) == 0) {
 956                                 pr_debug("%s: buff not yet loaded, no more todo\n",
 957                                          __func__);
 958                         } else {
 959                                 chan->load_state = S3C2410_DMALOAD_1RUNNING;
 960                                 s3c2410_dma_loadbuffer(chan, chan->next);
 961                         }
 962
 963                 } else if (chan->load_state == S3C2410_DMALOAD_1RUNNING) {
 964                         s3c2410_dma_loadbuffer(chan, chan->next);
 965                 }
 966         }
 967
 968
 969         local_irq_restore(flags);
 970
 971         return 0;
 972
 973 }
 974
 975 int
 976 s3c2410_dma_ctrl(enum dma_ch channel, enum s3c2410_chan_op op)
 977 {
 978         struct s3c2410_dma_chan *chan = s3c_dma_lookup_channel(channel);
 979
 980         if (chan == NULL)
 981                 return -EINVAL;
 982
 983         switch (op) {
 984         case S3C2410_DMAOP_START:
 985                 return s3c2410_dma_start(chan);
 986
 987         case S3C2410_DMAOP_STOP:
 988                 return s3c2410_dma_dostop(chan);
 989
 990         case S3C2410_DMAOP_PAUSE:
 991         case S3C2410_DMAOP_RESUME:
 992                 return -ENOENT;
 993
 994         case S3C2410_DMAOP_FLUSH:
 995                 return s3c2410_dma_flush(chan);
 996
 997         case S3C2410_DMAOP_STARTED:
 998                 return s3c2410_dma_started(chan);
 999
1000         case S3C2410_DMAOP_TIMEOUT:
1001                 return 0;
1002
1003         }
1004
1005         return -ENOENT;      /* unknown, don't bother */
1006 }
1007
1008 EXPORT_SYMBOL(s3c2410_dma_ctrl);
1009
1010 /* DMA configuration for each channel
1011  *
1012  * DISRCC -> source of the DMA (AHB,APB)
1013  * DISRC  -> source address of the DMA
1014  * DIDSTC -> destination of the DMA (AHB,APD)
1015  * DIDST  -> destination address of the DMA
1016 */
1017
1018 /* s3c2410_dma_config
1019  *
1020  * xfersize:     size of unit in bytes (1,2,4)
1021 */
1022
1023 int s3c2410_dma_config(enum dma_ch channel,
1024                        int xferunit)
1025 {
1026         struct s3c2410_dma_chan *chan = s3c_dma_lookup_channel(channel);
1027         unsigned int dcon;
1028
1029         pr_debug("%s: chan=%d, xfer_unit=%d\n", __func__, channel, xferunit);
1030
1031         if (chan == NULL)
1032                 return -EINVAL;
1033
1034         dcon = chan->dcon & dma_sel.dcon_mask;
1035         pr_debug("%s: dcon is %08x\n", __func__, dcon);
1036
1037         switch (chan->req_ch) {
1038         case DMACH_I2S_IN:
1039         case DMACH_I2S_OUT:
1040         case DMACH_PCM_IN:
1041         case DMACH_PCM_OUT:
1042         case DMACH_MIC_IN:
1043         default:
1044                 dcon |= S3C2410_DCON_HANDSHAKE;
1045                 dcon |= S3C2410_DCON_SYNC_PCLK;
1046                 break;
1047
1048         case DMACH_SDI:
1049                 /* note, ensure if need HANDSHAKE or not */
1050                 dcon |= S3C2410_DCON_SYNC_PCLK;
1051                 break;
1052
1053         case DMACH_XD0:
1054         case DMACH_XD1:
1055                 dcon |= S3C2410_DCON_HANDSHAKE;
1056                 dcon |= S3C2410_DCON_SYNC_HCLK;
1057                 break;
1058         }
1059
1060         switch (xferunit) {
1061         case 1:
1062                 dcon |= S3C2410_DCON_BYTE;
1063                 break;
1064
1065         case 2:
1066                 dcon |= S3C2410_DCON_HALFWORD;
1067                 break;
1068
1069         case 4:
1070                 dcon |= S3C2410_DCON_WORD;
1071                 break;
1072
1073         default:
1074                 pr_debug("%s: bad transfer size %d\n", __func__, xferunit);
1075                 return -EINVAL;
1076         }
1077
1078         dcon |= S3C2410_DCON_HWTRIG;
1079         dcon |= S3C2410_DCON_INTREQ;
1080
1081         pr_debug("%s: dcon now %08x\n", __func__, dcon);
1082
1083         chan->dcon = dcon;
1084         chan->xfer_unit = xferunit;
1085
1086         return 0;
1087 }
1088
1089 EXPORT_SYMBOL(s3c2410_dma_config);
1090
1091
1092 /* s3c2410_dma_devconfig
1093  *
1094  * configure the dma source/destination hardware type and address
1095  *
1096  * source:    DMA_FROM_DEVICE: source is hardware
1097  *            DMA_TO_DEVICE: source is memory
1098  *
1099  * devaddr:   physical address of the source
1100 */
1101
1102 int s3c2410_dma_devconfig(enum dma_ch channel,
1103                           enum dma_data_direction source,
1104                           unsigned long devaddr)
1105 {
1106         struct s3c2410_dma_chan *chan = s3c_dma_lookup_channel(channel);
1107         unsigned int hwcfg;
1108
1109         if (chan == NULL)
1110                 return -EINVAL;
1111
1112         pr_debug("%s: source=%d, devaddr=%08lx\n",
1113                  __func__, (int)source, devaddr);
1114
1115         chan->source = source;
1116         chan->dev_addr = devaddr;
1117
1118         switch (chan->req_ch) {
1119         case DMACH_XD0:
1120         case DMACH_XD1:
1121                 hwcfg = 0; /* AHB */
1122                 break;
1123
1124         default:
1125                 hwcfg = S3C2410_DISRCC_APB;
1126         }
1127
1128         /* always assume our peripheral desintation is a fixed
1129          * address in memory. */
1130          hwcfg |= S3C2410_DISRCC_INC;
1131
1132         switch (source) {
1133         case DMA_FROM_DEVICE:
1134                 /* source is hardware */
1135                 pr_debug("%s: hw source, devaddr=%08lx, hwcfg=%d\n",
1136                          __func__, devaddr, hwcfg);
1137                 dma_wrreg(chan, S3C2410_DMA_DISRCC, hwcfg & 3);
1138                 dma_wrreg(chan, S3C2410_DMA_DISRC,  devaddr);
1139                 dma_wrreg(chan, S3C2410_DMA_DIDSTC, (0<<1) | (0<<0));
1140
1141                 chan->addr_reg = dma_regaddr(chan, S3C2410_DMA_DIDST);
1142                 break;
1143
1144         case DMA_TO_DEVICE:
1145                 /* source is memory */
1146                 pr_debug("%s: mem source, devaddr=%08lx, hwcfg=%d\n",
1147                          __func__, devaddr, hwcfg);
1148                 dma_wrreg(chan, S3C2410_DMA_DISRCC, (0<<1) | (0<<0));
1149                 dma_wrreg(chan, S3C2410_DMA_DIDST,  devaddr);
1150                 dma_wrreg(chan, S3C2410_DMA_DIDSTC, hwcfg & 3);
1151
1152                 chan->addr_reg = dma_regaddr(chan, S3C2410_DMA_DISRC);
1153                 break;
1154
1155         default:
1156                 printk(KERN_ERR "dma%d: invalid source type (%d)\n",
1157                        channel, source);
1158
1159                 return -EINVAL;
1160         }
1161
1162         return 0;
1163 }
1164
1165 EXPORT_SYMBOL(s3c2410_dma_devconfig);
1166
1167 /* s3c2410_dma_getposition
1168  *
1169  * returns the current transfer points for the dma source and destination
1170 */
1171
1172 int s3c2410_dma_getposition(enum dma_ch channel, dma_addr_t *src, dma_addr_t *dst)
1173 {
1174         struct s3c2410_dma_chan *chan = s3c_dma_lookup_channel(channel);
1175
1176         if (chan == NULL)
1177                 return -EINVAL;
1178
1179         if (src != NULL)
1180                 *src = dma_rdreg(chan, S3C2410_DMA_DCSRC);
1181
1182         if (dst != NULL)
1183                 *dst = dma_rdreg(chan, S3C2410_DMA_DCDST);
1184
1185         return 0;
1186 }
1187
1188 EXPORT_SYMBOL(s3c2410_dma_getposition);
1189
1190 /* system core operations */
1191
1192 #ifdef CONFIG_PM
1193
1194 static void s3c2410_dma_suspend_chan(struct s3c2410_dma_chan *cp)
1195 {
1196         printk(KERN_DEBUG "suspending dma channel %d\n", cp->number);
1197
1198         if (dma_rdreg(cp, S3C2410_DMA_DMASKTRIG) & S3C2410_DMASKTRIG_ON) {
1199                 /* the dma channel is still working, which is probably
1200                  * a bad thing to do over suspend/resume. We stop the
1201                  * channel and assume that the client is either going to
1202                  * retry after resume, or that it is broken.
1203                  */
1204
1205                 printk(KERN_INFO "dma: stopping channel %d due to suspend\n",
1206                        cp->number);
1207
1208                 s3c2410_dma_dostop(cp);
1209         }
1210 }
1211
1212 static int s3c2410_dma_suspend(void)
1213 {
1214         struct s3c2410_dma_chan *cp = s3c2410_chans;
1215         int channel;
1216
1217         for (channel = 0; channel < dma_channels; cp++, channel++)
1218                 s3c2410_dma_suspend_chan(cp);
1219
1220         return 0;
1221 }
1222
1223 static void s3c2410_dma_resume_chan(struct s3c2410_dma_chan *cp)
1224 {
1225         unsigned int no = cp->number | DMACH_LOW_LEVEL;
1226
1227         /* restore channel's hardware configuration */
1228
1229         if (!cp->in_use)
1230                 return;
1231
1232         printk(KERN_INFO "dma%d: restoring configuration\n", cp->number);
1233
1234         s3c2410_dma_config(no, cp->xfer_unit);
1235         s3c2410_dma_devconfig(no, cp->source, cp->dev_addr);
1236
1237         /* re-select the dma source for this channel */
1238
1239         if (cp->map != NULL)
1240                 dma_sel.select(cp, cp->map);
1241 }
1242
1243 static void s3c2410_dma_resume(void)
1244 {
1245         struct s3c2410_dma_chan *cp = s3c2410_chans + dma_channels - 1;
1246         int channel;
1247
1248         for (channel = dma_channels - 1; channel >= 0; cp--, channel--)
1249                 s3c2410_dma_resume_chan(cp);
1250 }
1251
1252 #else
1253 #define s3c2410_dma_suspend NULL
1254 #define s3c2410_dma_resume  NULL
1255 #endif /* CONFIG_PM */
1256
1257 struct syscore_ops dma_syscore_ops = {
1258         .suspend        = s3c2410_dma_suspend,
1259         .resume         = s3c2410_dma_resume,
1260 };
1261
1262 /* kmem cache implementation */
1263
1264 static void s3c2410_dma_cache_ctor(void *p)
1265 {
1266         memset(p, 0, sizeof(struct s3c2410_dma_buf));
1267 }
1268
1269 /* initialisation code */
1270
1271 static int __init s3c24xx_dma_syscore_init(void)
1272 {
1273         register_syscore_ops(&dma_syscore_ops);
1274
1275         return 0;
1276 }
1277
1278 late_initcall(s3c24xx_dma_syscore_init);
1279
1280 int __init s3c24xx_dma_init(unsigned int channels, unsigned int irq,
1281                             unsigned int stride)
1282 {
1283         struct s3c2410_dma_chan *cp;
1284         int channel;
1285         int ret;
1286
1287         printk("S3C24XX DMA Driver, Copyright 2003-2006 Simtec Electronics\n");
1288
1289         dma_channels = channels;
1290
1291         dma_base = ioremap(S3C24XX_PA_DMA, stride * channels);
1292         if (dma_base == NULL) {
1293                 printk(KERN_ERR "dma failed to remap register block\n");
1294                 return -ENOMEM;
1295         }
1296
1297         dma_kmem = kmem_cache_create("dma_desc",
1298                                      sizeof(struct s3c2410_dma_buf), 0,
1299                                      SLAB_HWCACHE_ALIGN,
1300                                      s3c2410_dma_cache_ctor);
1301
1302         if (dma_kmem == NULL) {
1303                 printk(KERN_ERR "dma failed to make kmem cache\n");
1304                 ret = -ENOMEM;
1305                 goto err;
1306         }
1307
1308         for (channel = 0; channel < channels;  channel++) {
1309                 cp = &s3c2410_chans[channel];
1310
1311                 memset(cp, 0, sizeof(struct s3c2410_dma_chan));
1312
1313                 /* dma channel irqs are in order.. */
1314                 cp->number = channel;
1315                 cp->irq    = channel + irq;
1316                 cp->regs   = dma_base + (channel * stride);
1317
1318                 /* point current stats somewhere */
1319                 cp->stats  = &cp->stats_store;
1320                 cp->stats_store.timeout_shortest = LONG_MAX;
1321
1322                 /* basic channel configuration */
1323
1324                 cp->load_timeout = 1<<18;
1325
1326                 printk("DMA channel %d at %p, irq %d\n",
1327                        cp->number, cp->regs, cp->irq);
1328         }
1329
1330         return 0;
1331
1332  err:
1333         kmem_cache_destroy(dma_kmem);
1334         iounmap(dma_base);
1335         dma_base = NULL;
1336         return ret;
1337 }
1338
1339 int __init s3c2410_dma_init(void)
1340 {
1341         return s3c24xx_dma_init(4, IRQ_DMA0, 0x40);
1342 }
1343
1344 static inline int is_channel_valid(unsigned int channel)
1345 {
1346         return (channel & DMA_CH_VALID);
1347 }
1348
1349 static struct s3c24xx_dma_order *dma_order;
1350
1351
1352 /* s3c2410_dma_map_channel()
1353  *
1354  * turn the virtual channel number into a real, and un-used hardware
1355  * channel.
1356  *
1357  * first, try the dma ordering given to us by either the relevant
1358  * dma code, or the board. Then just find the first usable free
1359  * channel
1360 */
1361
1362 static struct s3c2410_dma_chan *s3c2410_dma_map_channel(int channel)
1363 {
1364         struct s3c24xx_dma_order_ch *ord = NULL;
1365         struct s3c24xx_dma_map *ch_map;
1366         struct s3c2410_dma_chan *dmach;
1367         int ch;
1368
1369         if (dma_sel.map == NULL || channel > dma_sel.map_size)
1370                 return NULL;
1371
1372         ch_map = dma_sel.map + channel;
1373
1374         /* first, try the board mapping */
1375
1376         if (dma_order) {
1377                 ord = &dma_order->channels[channel];
1378
1379                 for (ch = 0; ch < dma_channels; ch++) {
1380                         int tmp;
1381                         if (!is_channel_valid(ord->list[ch]))
1382                                 continue;
1383
1384                         tmp = ord->list[ch] & ~DMA_CH_VALID;
1385                         if (s3c2410_chans[tmp].in_use == 0) {
1386                                 ch = tmp;
1387                                 goto found;
1388                         }
1389                 }
1390
1391                 if (ord->flags & DMA_CH_NEVER)
1392                         return NULL;
1393         }
1394
1395         /* second, search the channel map for first free */
1396
1397         for (ch = 0; ch < dma_channels; ch++) {
1398                 if (!is_channel_valid(ch_map->channels[ch]))
1399                         continue;
1400
1401                 if (s3c2410_chans[ch].in_use == 0) {
1402                         printk("mapped channel %d to %d\n", channel, ch);
1403                         break;
1404                 }
1405         }
1406
1407         if (ch >= dma_channels)
1408                 return NULL;
1409
1410         /* update our channel mapping */
1411
1412  found:
1413         dmach = &s3c2410_chans[ch];
1414         dmach->map = ch_map;
1415         dmach->req_ch = channel;
1416         s3c_dma_chan_map[channel] = dmach;
1417
1418         /* select the channel */
1419
1420         (dma_sel.select)(dmach, ch_map);
1421
1422         return dmach;
1423 }
1424
1425 static int s3c24xx_dma_check_entry(struct s3c24xx_dma_map *map, int ch)
1426 {
1427         return 0;
1428 }
1429
1430 int __init s3c24xx_dma_init_map(struct s3c24xx_dma_selection *sel)
1431 {
1432         struct s3c24xx_dma_map *nmap;
1433         size_t map_sz = sizeof(*nmap) * sel->map_size;
1434         int ptr;
1435
1436         nmap = kmemdup(sel->map, map_sz, GFP_KERNEL);
1437         if (nmap == NULL)
1438                 return -ENOMEM;
1439
1440         memcpy(&dma_sel, sel, sizeof(*sel));
1441
1442         dma_sel.map = nmap;
1443
1444         for (ptr = 0; ptr < sel->map_size; ptr++)
1445                 s3c24xx_dma_check_entry(nmap+ptr, ptr);
1446
1447         return 0;
1448 }
1449
1450 int __init s3c24xx_dma_order_set(struct s3c24xx_dma_order *ord)
1451 {
1452         struct s3c24xx_dma_order *nord = dma_order;
1453
1454         if (nord == NULL)
1455                 nord = kmalloc(sizeof(struct s3c24xx_dma_order), GFP_KERNEL);
1456
1457         if (nord == NULL) {
1458                 printk(KERN_ERR "no memory to store dma channel order\n");
1459                 return -ENOMEM;
1460         }
1461
1462         dma_order = nord;
1463         memcpy(nord, ord, sizeof(struct s3c24xx_dma_order));
1464         return 0;
1465 }