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   1 /* linux/arch/arm/plat-s3c24xx/dma.c
   2  *
   3  * Copyright (c) 2003-2005,2006 Simtec Electronics
   4  *      Ben Dooks <ben@simtec.co.uk>
   5  *
   6  * S3C2410 DMA core
   7  *
   8  * http://armlinux.simtec.co.uk/
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13 */
  14
  15
  16 #ifdef CONFIG_S3C2410_DMA_DEBUG
  17 #define DEBUG
  18 #endif
  19
  20 #include <linux/module.h>
  21 #include <linux/init.h>
  22 #include <linux/sched.h>
  23 #include <linux/spinlock.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/sysdev.h>
  26 #include <linux/slab.h>
  27 #include <linux/errno.h>
  28 #include <linux/delay.h>
  29
  30 #include <asm/system.h>
  31 #include <asm/irq.h>
  32 #include <asm/hardware.h>
  33 #include <asm/io.h>
  34 #include <asm/dma.h>
  35
  36 #include <asm/mach/dma.h>
  37 #include <asm/arch/map.h>
  38
  39 #include <asm/plat-s3c24xx/dma.h>
  40
  41 /* io map for dma */
  42 static void __iomem *dma_base;
  43 static struct kmem_cache *dma_kmem;
  44
  45 static int dma_channels;
  46
  47 struct s3c24xx_dma_selection dma_sel;
  48
  49 /* dma channel state information */
  50 struct s3c2410_dma_chan s3c2410_chans[S3C2410_DMA_CHANNELS];
  51
  52 /* debugging functions */
  53
  54 #define BUF_MAGIC (0xcafebabe)
  55
  56 #define dmawarn(fmt...) printk(KERN_DEBUG fmt)
  57
  58 #define dma_regaddr(chan, reg) ((chan)->regs + (reg))
  59
  60 #if 1
  61 #define dma_wrreg(chan, reg, val) writel((val), (chan)->regs + (reg))
  62 #else
  63 static inline void
  64 dma_wrreg(struct s3c2410_dma_chan *chan, int reg, unsigned long val)
  65 {
  66         pr_debug("writing %08x to register %08x\n",(unsigned int)val,reg);
  67         writel(val, dma_regaddr(chan, reg));
  68 }
  69 #endif
  70
  71 #define dma_rdreg(chan, reg) readl((chan)->regs + (reg))
  72
  73 /* captured register state for debug */
  74
  75 struct s3c2410_dma_regstate {
  76         unsigned long         dcsrc;
  77         unsigned long         disrc;
  78         unsigned long         dstat;
  79         unsigned long         dcon;
  80         unsigned long         dmsktrig;
  81 };
  82
  83 #ifdef CONFIG_S3C2410_DMA_DEBUG
  84
  85 /* dmadbg_showregs
  86  *
  87  * simple debug routine to print the current state of the dma registers
  88 */
  89
  90 static void
  91 dmadbg_capture(struct s3c2410_dma_chan *chan, struct s3c2410_dma_regstate *regs)
  92 {
  93         regs->dcsrc    = dma_rdreg(chan, S3C2410_DMA_DCSRC);
  94         regs->disrc    = dma_rdreg(chan, S3C2410_DMA_DISRC);
  95         regs->dstat    = dma_rdreg(chan, S3C2410_DMA_DSTAT);
  96         regs->dcon     = dma_rdreg(chan, S3C2410_DMA_DCON);
  97         regs->dmsktrig = dma_rdreg(chan, S3C2410_DMA_DMASKTRIG);
  98 }
  99
 100 static void
 101 dmadbg_dumpregs(const char *fname, int line, struct s3c2410_dma_chan *chan,
 102                  struct s3c2410_dma_regstate *regs)
 103 {
 104         printk(KERN_DEBUG "dma%d: %s:%d: DCSRC=%08lx, DISRC=%08lx, DSTAT=%08lx DMT=%02lx, DCON=%08lx\n",
 105                chan->number, fname, line,
 106                regs->dcsrc, regs->disrc, regs->dstat, regs->dmsktrig,
 107                regs->dcon);
 108 }
 109
 110 static void
 111 dmadbg_showchan(const char *fname, int line, struct s3c2410_dma_chan *chan)
 112 {
 113         struct s3c2410_dma_regstate state;
 114
 115         dmadbg_capture(chan, &state);
 116
 117         printk(KERN_DEBUG "dma%d: %s:%d: ls=%d, cur=%p, %p %p\n",
 118                chan->number, fname, line, chan->load_state,
 119                chan->curr, chan->next, chan->end);
 120
 121         dmadbg_dumpregs(fname, line, chan, &state);
 122 }
 123
 124 static void
 125 dmadbg_showregs(const char *fname, int line, struct s3c2410_dma_chan *chan)
 126 {
 127         struct s3c2410_dma_regstate state;
 128
 129         dmadbg_capture(chan, &state);
 130         dmadbg_dumpregs(fname, line, chan, &state);
 131 }
 132
 133 #define dbg_showregs(chan) dmadbg_showregs(__FUNCTION__, __LINE__, (chan))
 134 #define dbg_showchan(chan) dmadbg_showchan(__FUNCTION__, __LINE__, (chan))
 135 #else
 136 #define dbg_showregs(chan) do { } while(0)
 137 #define dbg_showchan(chan) do { } while(0)
 138 #endif /* CONFIG_S3C2410_DMA_DEBUG */
 139
 140 static struct s3c2410_dma_chan *dma_chan_map[DMACH_MAX];
 141
 142 /* lookup_dma_channel
 143  *
 144  * change the dma channel number given into a real dma channel id
 145 */
 146
 147 static struct s3c2410_dma_chan *lookup_dma_channel(unsigned int channel)
 148 {
 149         if (channel & DMACH_LOW_LEVEL)
 150                 return &s3c2410_chans[channel & ~DMACH_LOW_LEVEL];
 151         else
 152                 return dma_chan_map[channel];
 153 }
 154
 155 /* s3c2410_dma_stats_timeout
 156  *
 157  * Update DMA stats from timeout info
 158 */
 159
 160 static void
 161 s3c2410_dma_stats_timeout(struct s3c2410_dma_stats *stats, int val)
 162 {
 163         if (stats == NULL)
 164                 return;
 165
 166         if (val > stats->timeout_longest)
 167                 stats->timeout_longest = val;
 168         if (val < stats->timeout_shortest)
 169                 stats->timeout_shortest = val;
 170
 171         stats->timeout_avg += val;
 172 }
 173
 174 /* s3c2410_dma_waitforload
 175  *
 176  * wait for the DMA engine to load a buffer, and update the state accordingly
 177 */
 178
 179 static int
 180 s3c2410_dma_waitforload(struct s3c2410_dma_chan *chan, int line)
 181 {
 182         int timeout = chan->load_timeout;
 183         int took;
 184
 185         if (chan->load_state != S3C2410_DMALOAD_1LOADED) {
 186                 printk(KERN_ERR "dma%d: s3c2410_dma_waitforload() called in loadstate %d from line %d\n", chan->number, chan->load_state, line);
 187                 return 0;
 188         }
 189
 190         if (chan->stats != NULL)
 191                 chan->stats->loads++;
 192
 193         while (--timeout > 0) {
 194                 if ((dma_rdreg(chan, S3C2410_DMA_DSTAT) << (32-20)) != 0) {
 195                         took = chan->load_timeout - timeout;
 196
 197                         s3c2410_dma_stats_timeout(chan->stats, took);
 198
 199                         switch (chan->load_state) {
 200                         case S3C2410_DMALOAD_1LOADED:
 201                                 chan->load_state = S3C2410_DMALOAD_1RUNNING;
 202                                 break;
 203
 204                         default:
 205                                 printk(KERN_ERR "dma%d: unknown load_state in s3c2410_dma_waitforload() %d\n", chan->number, chan->load_state);
 206                         }
 207
 208                         return 1;
 209                 }
 210         }
 211
 212         if (chan->stats != NULL) {
 213                 chan->stats->timeout_failed++;
 214         }
 215
 216         return 0;
 217 }
 218
 219
 220
 221 /* s3c2410_dma_loadbuffer
 222  *
 223  * load a buffer, and update the channel state
 224 */
 225
 226 static inline int
 227 s3c2410_dma_loadbuffer(struct s3c2410_dma_chan *chan,
 228                        struct s3c2410_dma_buf *buf)
 229 {
 230         unsigned long reload;
 231
 232         pr_debug("s3c2410_chan_loadbuffer: loading buff %p (0x%08lx,0x%06x)\n",
 233                  buf, (unsigned long)buf->data, buf->size);
 234
 235         if (buf == NULL) {
 236                 dmawarn("buffer is NULL\n");
 237                 return -EINVAL;
 238         }
 239
 240         /* check the state of the channel before we do anything */
 241
 242         if (chan->load_state == S3C2410_DMALOAD_1LOADED) {
 243                 dmawarn("load_state is S3C2410_DMALOAD_1LOADED\n");
 244         }
 245
 246         if (chan->load_state == S3C2410_DMALOAD_1LOADED_1RUNNING) {
 247                 dmawarn("state is S3C2410_DMALOAD_1LOADED_1RUNNING\n");
 248         }
 249
 250         /* it would seem sensible if we are the last buffer to not bother
 251          * with the auto-reload bit, so that the DMA engine will not try
 252          * and load another transfer after this one has finished...
 253          */
 254         if (chan->load_state == S3C2410_DMALOAD_NONE) {
 255                 pr_debug("load_state is none, checking for noreload (next=%p)\n",
 256                          buf->next);
 257                 reload = (buf->next == NULL) ? S3C2410_DCON_NORELOAD : 0;
 258         } else {
 259                 //pr_debug("load_state is %d => autoreload\n", chan->load_state);
 260                 reload = S3C2410_DCON_AUTORELOAD;
 261         }
 262
 263         if ((buf->data & 0xf0000000) != 0x30000000) {
 264                 dmawarn("dmaload: buffer is %p\n", (void *)buf->data);
 265         }
 266
 267         writel(buf->data, chan->addr_reg);
 268
 269         dma_wrreg(chan, S3C2410_DMA_DCON,
 270                   chan->dcon | reload | (buf->size/chan->xfer_unit));
 271
 272         chan->next = buf->next;
 273
 274         /* update the state of the channel */
 275
 276         switch (chan->load_state) {
 277         case S3C2410_DMALOAD_NONE:
 278                 chan->load_state = S3C2410_DMALOAD_1LOADED;
 279                 break;
 280
 281         case S3C2410_DMALOAD_1RUNNING:
 282                 chan->load_state = S3C2410_DMALOAD_1LOADED_1RUNNING;
 283                 break;
 284
 285         default:
 286                 dmawarn("dmaload: unknown state %d in loadbuffer\n",
 287                         chan->load_state);
 288                 break;
 289         }
 290
 291         return 0;
 292 }
 293
 294 /* s3c2410_dma_call_op
 295  *
 296  * small routine to call the op routine with the given op if it has been
 297  * registered
 298 */
 299
 300 static void
 301 s3c2410_dma_call_op(struct s3c2410_dma_chan *chan, enum s3c2410_chan_op op)
 302 {
 303         if (chan->op_fn != NULL) {
 304                 (chan->op_fn)(chan, op);
 305         }
 306 }
 307
 308 /* s3c2410_dma_buffdone
 309  *
 310  * small wrapper to check if callback routine needs to be called, and
 311  * if so, call it
 312 */
 313
 314 static inline void
 315 s3c2410_dma_buffdone(struct s3c2410_dma_chan *chan, struct s3c2410_dma_buf *buf,
 316                      enum s3c2410_dma_buffresult result)
 317 {
 318 #if 0
 319         pr_debug("callback_fn=%p, buf=%p, id=%p, size=%d, result=%d\n",
 320                  chan->callback_fn, buf, buf->id, buf->size, result);
 321 #endif
 322
 323         if (chan->callback_fn != NULL) {
 324                 (chan->callback_fn)(chan, buf->id, buf->size, result);
 325         }
 326 }
 327
 328 /* s3c2410_dma_start
 329  *
 330  * start a dma channel going
 331 */
 332
 333 static int s3c2410_dma_start(struct s3c2410_dma_chan *chan)
 334 {
 335         unsigned long tmp;
 336         unsigned long flags;
 337
 338         pr_debug("s3c2410_start_dma: channel=%d\n", chan->number);
 339
 340         local_irq_save(flags);
 341
 342         if (chan->state == S3C2410_DMA_RUNNING) {
 343                 pr_debug("s3c2410_start_dma: already running (%d)\n", chan->state);
 344                 local_irq_restore(flags);
 345                 return 0;
 346         }
 347
 348         chan->state = S3C2410_DMA_RUNNING;
 349
 350         /* check wether there is anything to load, and if not, see
 351          * if we can find anything to load
 352          */
 353
 354         if (chan->load_state == S3C2410_DMALOAD_NONE) {
 355                 if (chan->next == NULL) {
 356                         printk(KERN_ERR "dma%d: channel has nothing loaded\n",
 357                                chan->number);
 358                         chan->state = S3C2410_DMA_IDLE;
 359                         local_irq_restore(flags);
 360                         return -EINVAL;
 361                 }
 362
 363                 s3c2410_dma_loadbuffer(chan, chan->next);
 364         }
 365
 366         dbg_showchan(chan);
 367
 368         /* enable the channel */
 369
 370         if (!chan->irq_enabled) {
 371                 enable_irq(chan->irq);
 372                 chan->irq_enabled = 1;
 373         }
 374
 375         /* start the channel going */
 376
 377         tmp = dma_rdreg(chan, S3C2410_DMA_DMASKTRIG);
 378         tmp &= ~S3C2410_DMASKTRIG_STOP;
 379         tmp |= S3C2410_DMASKTRIG_ON;
 380         dma_wrreg(chan, S3C2410_DMA_DMASKTRIG, tmp);
 381
 382         pr_debug("dma%d: %08lx to DMASKTRIG\n", chan->number, tmp);
 383
 384 #if 0
 385         /* the dma buffer loads should take care of clearing the AUTO
 386          * reloading feature */
 387         tmp = dma_rdreg(chan, S3C2410_DMA_DCON);
 388         tmp &= ~S3C2410_DCON_NORELOAD;
 389         dma_wrreg(chan, S3C2410_DMA_DCON, tmp);
 390 #endif
 391
 392         s3c2410_dma_call_op(chan, S3C2410_DMAOP_START);
 393
 394         dbg_showchan(chan);
 395
 396         /* if we've only loaded one buffer onto the channel, then chec
 397          * to see if we have another, and if so, try and load it so when
 398          * the first buffer is finished, the new one will be loaded onto
 399          * the channel */
 400
 401         if (chan->next != NULL) {
 402                 if (chan->load_state == S3C2410_DMALOAD_1LOADED) {
 403
 404                         if (s3c2410_dma_waitforload(chan, __LINE__) == 0) {
 405                                 pr_debug("%s: buff not yet loaded, no more todo\n",
 406                                          __FUNCTION__);
 407                         } else {
 408                                 chan->load_state = S3C2410_DMALOAD_1RUNNING;
 409                                 s3c2410_dma_loadbuffer(chan, chan->next);
 410                         }
 411
 412                 } else if (chan->load_state == S3C2410_DMALOAD_1RUNNING) {
 413                         s3c2410_dma_loadbuffer(chan, chan->next);
 414                 }
 415         }
 416
 417
 418         local_irq_restore(flags);
 419
 420         return 0;
 421 }
 422
 423 /* s3c2410_dma_canload
 424  *
 425  * work out if we can queue another buffer into the DMA engine
 426 */
 427
 428 static int
 429 s3c2410_dma_canload(struct s3c2410_dma_chan *chan)
 430 {
 431         if (chan->load_state == S3C2410_DMALOAD_NONE ||
 432             chan->load_state == S3C2410_DMALOAD_1RUNNING)
 433                 return 1;
 434
 435         return 0;
 436 }
 437
 438 /* s3c2410_dma_enqueue
 439  *
 440  * queue an given buffer for dma transfer.
 441  *
 442  * id         the device driver's id information for this buffer
 443  * data       the physical address of the buffer data
 444  * size       the size of the buffer in bytes
 445  *
 446  * If the channel is not running, then the flag S3C2410_DMAF_AUTOSTART
 447  * is checked, and if set, the channel is started. If this flag isn't set,
 448  * then an error will be returned.
 449  *
 450  * It is possible to queue more than one DMA buffer onto a channel at
 451  * once, and the code will deal with the re-loading of the next buffer
 452  * when necessary.
 453 */
 454
 455 int s3c2410_dma_enqueue(unsigned int channel, void *id,
 456                         dma_addr_t data, int size)
 457 {
 458         struct s3c2410_dma_chan *chan = lookup_dma_channel(channel);
 459         struct s3c2410_dma_buf *buf;
 460         unsigned long flags;
 461
 462         if (chan == NULL)
 463                 return -EINVAL;
 464
 465         pr_debug("%s: id=%p, data=%08x, size=%d\n",
 466                  __FUNCTION__, id, (unsigned int)data, size);
 467
 468         buf = kmem_cache_alloc(dma_kmem, GFP_ATOMIC);
 469         if (buf == NULL) {
 470                 pr_debug("%s: out of memory (%ld alloc)\n",
 471                          __FUNCTION__, (long)sizeof(*buf));
 472                 return -ENOMEM;
 473         }
 474
 475         //pr_debug("%s: new buffer %p\n", __FUNCTION__, buf);
 476         //dbg_showchan(chan);
 477
 478         buf->next  = NULL;
 479         buf->data  = buf->ptr = data;
 480         buf->size  = size;
 481         buf->id    = id;
 482         buf->magic = BUF_MAGIC;
 483
 484         local_irq_save(flags);
 485
 486         if (chan->curr == NULL) {
 487                 /* we've got nothing loaded... */
 488                 pr_debug("%s: buffer %p queued onto empty channel\n",
 489                          __FUNCTION__, buf);
 490
 491                 chan->curr = buf;
 492                 chan->end  = buf;
 493                 chan->next = NULL;
 494         } else {
 495                 pr_debug("dma%d: %s: buffer %p queued onto non-empty channel\n",
 496                          chan->number, __FUNCTION__, buf);
 497
 498                 if (chan->end == NULL)
 499                         pr_debug("dma%d: %s: %p not empty, and chan->end==NULL?\n",
 500                                  chan->number, __FUNCTION__, chan);
 501
 502                 chan->end->next = buf;
 503                 chan->end = buf;
 504         }
 505
 506         /* if necessary, update the next buffer field */
 507         if (chan->next == NULL)
 508                 chan->next = buf;
 509
 510         /* check to see if we can load a buffer */
 511         if (chan->state == S3C2410_DMA_RUNNING) {
 512                 if (chan->load_state == S3C2410_DMALOAD_1LOADED && 1) {
 513                         if (s3c2410_dma_waitforload(chan, __LINE__) == 0) {
 514                                 printk(KERN_ERR "dma%d: loadbuffer:"
 515                                        "timeout loading buffer\n",
 516                                        chan->number);
 517                                 dbg_showchan(chan);
 518                                 local_irq_restore(flags);
 519                                 return -EINVAL;
 520                         }
 521                 }
 522
 523                 while (s3c2410_dma_canload(chan) && chan->next != NULL) {
 524                         s3c2410_dma_loadbuffer(chan, chan->next);
 525                 }
 526         } else if (chan->state == S3C2410_DMA_IDLE) {
 527                 if (chan->flags & S3C2410_DMAF_AUTOSTART) {
 528                         s3c2410_dma_ctrl(chan->number, S3C2410_DMAOP_START);
 529                 }
 530         }
 531
 532         local_irq_restore(flags);
 533         return 0;
 534 }
 535
 536 EXPORT_SYMBOL(s3c2410_dma_enqueue);
 537
 538 static inline void
 539 s3c2410_dma_freebuf(struct s3c2410_dma_buf *buf)
 540 {
 541         int magicok = (buf->magic == BUF_MAGIC);
 542
 543         buf->magic = -1;
 544
 545         if (magicok) {
 546                 kmem_cache_free(dma_kmem, buf);
 547         } else {
 548                 printk("s3c2410_dma_freebuf: buff %p with bad magic\n", buf);
 549         }
 550 }
 551
 552 /* s3c2410_dma_lastxfer
 553  *
 554  * called when the system is out of buffers, to ensure that the channel
 555  * is prepared for shutdown.
 556 */
 557
 558 static inline void
 559 s3c2410_dma_lastxfer(struct s3c2410_dma_chan *chan)
 560 {
 561 #if 0
 562         pr_debug("dma%d: s3c2410_dma_lastxfer: load_state %d\n",
 563                  chan->number, chan->load_state);
 564 #endif
 565
 566         switch (chan->load_state) {
 567         case S3C2410_DMALOAD_NONE:
 568                 break;
 569
 570         case S3C2410_DMALOAD_1LOADED:
 571                 if (s3c2410_dma_waitforload(chan, __LINE__) == 0) {
 572                                 /* flag error? */
 573                         printk(KERN_ERR "dma%d: timeout waiting for load (%s)\n",
 574                                chan->number, __FUNCTION__);
 575                         return;
 576                 }
 577                 break;
 578
 579         case S3C2410_DMALOAD_1LOADED_1RUNNING:
 580                 /* I belive in this case we do not have anything to do
 581                  * until the next buffer comes along, and we turn off the
 582                  * reload */
 583                 return;
 584
 585         default:
 586                 pr_debug("dma%d: lastxfer: unhandled load_state %d with no next\n",
 587                          chan->number, chan->load_state);
 588                 return;
 589
 590         }
 591
 592         /* hopefully this'll shut the damned thing up after the transfer... */
 593         dma_wrreg(chan, S3C2410_DMA_DCON, chan->dcon | S3C2410_DCON_NORELOAD);
 594 }
 595
 596
 597 #define dmadbg2(x...)
 598
 599 static irqreturn_t
 600 s3c2410_dma_irq(int irq, void *devpw)
 601 {
 602         struct s3c2410_dma_chan *chan = (struct s3c2410_dma_chan *)devpw;
 603         struct s3c2410_dma_buf  *buf;
 604
 605         buf = chan->curr;
 606
 607         dbg_showchan(chan);
 608
 609         /* modify the channel state */
 610
 611         switch (chan->load_state) {
 612         case S3C2410_DMALOAD_1RUNNING:
 613                 /* TODO - if we are running only one buffer, we probably
 614                  * want to reload here, and then worry about the buffer
 615                  * callback */
 616
 617                 chan->load_state = S3C2410_DMALOAD_NONE;
 618                 break;
 619
 620         case S3C2410_DMALOAD_1LOADED:
 621                 /* iirc, we should go back to NONE loaded here, we
 622                  * had a buffer, and it was never verified as being
 623                  * loaded.
 624                  */
 625
 626                 chan->load_state = S3C2410_DMALOAD_NONE;
 627                 break;
 628
 629         case S3C2410_DMALOAD_1LOADED_1RUNNING:
 630                 /* we'll worry about checking to see if another buffer is
 631                  * ready after we've called back the owner. This should
 632                  * ensure we do not wait around too long for the DMA
 633                  * engine to start the next transfer
 634                  */
 635
 636                 chan->load_state = S3C2410_DMALOAD_1LOADED;
 637                 break;
 638
 639         case S3C2410_DMALOAD_NONE:
 640                 printk(KERN_ERR "dma%d: IRQ with no loaded buffer?\n",
 641                        chan->number);
 642                 break;
 643
 644         default:
 645                 printk(KERN_ERR "dma%d: IRQ in invalid load_state %d\n",
 646                        chan->number, chan->load_state);
 647                 break;
 648         }
 649
 650         if (buf != NULL) {
 651                 /* update the chain to make sure that if we load any more
 652                  * buffers when we call the callback function, things should
 653                  * work properly */
 654
 655                 chan->curr = buf->next;
 656                 buf->next  = NULL;
 657
 658                 if (buf->magic != BUF_MAGIC) {
 659                         printk(KERN_ERR "dma%d: %s: buf %p incorrect magic\n",
 660                                chan->number, __FUNCTION__, buf);
 661                         return IRQ_HANDLED;
 662                 }
 663
 664                 s3c2410_dma_buffdone(chan, buf, S3C2410_RES_OK);
 665
 666                 /* free resouces */
 667                 s3c2410_dma_freebuf(buf);
 668         } else {
 669         }
 670
 671         /* only reload if the channel is still running... our buffer done
 672          * routine may have altered the state by requesting the dma channel
 673          * to stop or shutdown... */
 674
 675         /* todo: check that when the channel is shut-down from inside this
 676          * function, we cope with unsetting reload, etc */
 677
 678         if (chan->next != NULL && chan->state != S3C2410_DMA_IDLE) {
 679                 unsigned long flags;
 680
 681                 switch (chan->load_state) {
 682                 case S3C2410_DMALOAD_1RUNNING:
 683                         /* don't need to do anything for this state */
 684                         break;
 685
 686                 case S3C2410_DMALOAD_NONE:
 687                         /* can load buffer immediately */
 688                         break;
 689
 690                 case S3C2410_DMALOAD_1LOADED:
 691                         if (s3c2410_dma_waitforload(chan, __LINE__) == 0) {
 692                                 /* flag error? */
 693                                 printk(KERN_ERR "dma%d: timeout waiting for load (%s)\n",
 694                                        chan->number, __FUNCTION__);
 695                                 return IRQ_HANDLED;
 696                         }
 697
 698                         break;
 699
 700                 case S3C2410_DMALOAD_1LOADED_1RUNNING:
 701                         goto no_load;
 702
 703                 default:
 704                         printk(KERN_ERR "dma%d: unknown load_state in irq, %d\n",
 705                                chan->number, chan->load_state);
 706                         return IRQ_HANDLED;
 707                 }
 708
 709                 local_irq_save(flags);
 710                 s3c2410_dma_loadbuffer(chan, chan->next);
 711                 local_irq_restore(flags);
 712         } else {
 713                 s3c2410_dma_lastxfer(chan);
 714
 715                 /* see if we can stop this channel.. */
 716                 if (chan->load_state == S3C2410_DMALOAD_NONE) {
 717                         pr_debug("dma%d: end of transfer, stopping channel (%ld)\n",
 718                                  chan->number, jiffies);
 719                         s3c2410_dma_ctrl(chan->number | DMACH_LOW_LEVEL,
 720                                          S3C2410_DMAOP_STOP);
 721                 }
 722         }
 723
 724  no_load:
 725         return IRQ_HANDLED;
 726 }
 727
 728 static struct s3c2410_dma_chan *s3c2410_dma_map_channel(int channel);
 729
 730 /* s3c2410_request_dma
 731  *
 732  * get control of an dma channel
 733 */
 734
 735 int s3c2410_dma_request(unsigned int channel,
 736                         struct s3c2410_dma_client *client,
 737                         void *dev)
 738 {
 739         struct s3c2410_dma_chan *chan;
 740         unsigned long flags;
 741         int err;
 742
 743         pr_debug("dma%d: s3c2410_request_dma: client=%s, dev=%p\n",
 744                  channel, client->name, dev);
 745
 746         local_irq_save(flags);
 747
 748         chan = s3c2410_dma_map_channel(channel);
 749         if (chan == NULL) {
 750                 local_irq_restore(flags);
 751                 return -EBUSY;
 752         }
 753
 754         dbg_showchan(chan);
 755
 756         chan->client = client;
 757         chan->in_use = 1;
 758
 759         if (!chan->irq_claimed) {
 760                 pr_debug("dma%d: %s : requesting irq %d\n",
 761                          channel, __FUNCTION__, chan->irq);
 762
 763                 chan->irq_claimed = 1;
 764                 local_irq_restore(flags);
 765
 766                 err = request_irq(chan->irq, s3c2410_dma_irq, IRQF_DISABLED,
 767                                   client->name, (void *)chan);
 768
 769                 local_irq_save(flags);
 770
 771                 if (err) {
 772                         chan->in_use = 0;
 773                         chan->irq_claimed = 0;
 774                         local_irq_restore(flags);
 775
 776                         printk(KERN_ERR "%s: cannot get IRQ %d for DMA %d\n",
 777                                client->name, chan->irq, chan->number);
 778                         return err;
 779                 }
 780
 781                 chan->irq_enabled = 1;
 782         }
 783
 784         local_irq_restore(flags);
 785
 786         /* need to setup */
 787
 788         pr_debug("%s: channel initialised, %p\n", __FUNCTION__, chan);
 789
 790         return 0;
 791 }
 792
 793 EXPORT_SYMBOL(s3c2410_dma_request);
 794
 795 /* s3c2410_dma_free
 796  *
 797  * release the given channel back to the system, will stop and flush
 798  * any outstanding transfers, and ensure the channel is ready for the
 799  * next claimant.
 800  *
 801  * Note, although a warning is currently printed if the freeing client
 802  * info is not the same as the registrant's client info, the free is still
 803  * allowed to go through.
 804 */
 805
 806 int s3c2410_dma_free(dmach_t channel, struct s3c2410_dma_client *client)
 807 {
 808         struct s3c2410_dma_chan *chan = lookup_dma_channel(channel);
 809         unsigned long flags;
 810
 811         if (chan == NULL)
 812                 return -EINVAL;
 813
 814         local_irq_save(flags);
 815
 816         if (chan->client != client) {
 817                 printk(KERN_WARNING "dma%d: possible free from different client (channel %p, passed %p)\n",
 818                        channel, chan->client, client);
 819         }
 820
 821         /* sort out stopping and freeing the channel */
 822
 823         if (chan->state != S3C2410_DMA_IDLE) {
 824                 pr_debug("%s: need to stop dma channel %p\n",
 825                        __FUNCTION__, chan);
 826
 827                 /* possibly flush the channel */
 828                 s3c2410_dma_ctrl(channel, S3C2410_DMAOP_STOP);
 829         }
 830
 831         chan->client = NULL;
 832         chan->in_use = 0;
 833
 834         if (chan->irq_claimed)
 835                 free_irq(chan->irq, (void *)chan);
 836
 837         chan->irq_claimed = 0;
 838
 839         if (!(channel & DMACH_LOW_LEVEL))
 840                 dma_chan_map[channel] = NULL;
 841
 842         local_irq_restore(flags);
 843
 844         return 0;
 845 }
 846
 847 EXPORT_SYMBOL(s3c2410_dma_free);
 848
 849 static int s3c2410_dma_dostop(struct s3c2410_dma_chan *chan)
 850 {
 851         unsigned long flags;
 852         unsigned long tmp;
 853
 854         pr_debug("%s:\n", __FUNCTION__);
 855
 856         dbg_showchan(chan);
 857
 858         local_irq_save(flags);
 859
 860         s3c2410_dma_call_op(chan,  S3C2410_DMAOP_STOP);
 861
 862         tmp = dma_rdreg(chan, S3C2410_DMA_DMASKTRIG);
 863         tmp |= S3C2410_DMASKTRIG_STOP;
 864         //tmp &= ~S3C2410_DMASKTRIG_ON;
 865         dma_wrreg(chan, S3C2410_DMA_DMASKTRIG, tmp);
 866
 867 #if 0
 868         /* should also clear interrupts, according to WinCE BSP */
 869         tmp = dma_rdreg(chan, S3C2410_DMA_DCON);
 870         tmp |= S3C2410_DCON_NORELOAD;
 871         dma_wrreg(chan, S3C2410_DMA_DCON, tmp);
 872 #endif
 873
 874         /* should stop do this, or should we wait for flush? */
 875         chan->state      = S3C2410_DMA_IDLE;
 876         chan->load_state = S3C2410_DMALOAD_NONE;
 877
 878         local_irq_restore(flags);
 879
 880         return 0;
 881 }
 882
 883 void s3c2410_dma_waitforstop(struct s3c2410_dma_chan *chan)
 884 {
 885         unsigned long tmp;
 886         unsigned int timeout = 0x10000;
 887
 888         while (timeout-- > 0) {
 889                 tmp = dma_rdreg(chan, S3C2410_DMA_DMASKTRIG);
 890
 891                 if (!(tmp & S3C2410_DMASKTRIG_ON))
 892                         return;
 893         }
 894
 895         pr_debug("dma%d: failed to stop?\n", chan->number);
 896 }
 897
 898
 899 /* s3c2410_dma_flush
 900  *
 901  * stop the channel, and remove all current and pending transfers
 902 */
 903
 904 static int s3c2410_dma_flush(struct s3c2410_dma_chan *chan)
 905 {
 906         struct s3c2410_dma_buf *buf, *next;
 907         unsigned long flags;
 908
 909         pr_debug("%s: chan %p (%d)\n", __FUNCTION__, chan, chan->number);
 910
 911         dbg_showchan(chan);
 912
 913         local_irq_save(flags);
 914
 915         if (chan->state != S3C2410_DMA_IDLE) {
 916                 pr_debug("%s: stopping channel...\n", __FUNCTION__ );
 917                 s3c2410_dma_ctrl(chan->number, S3C2410_DMAOP_STOP);
 918         }
 919
 920         buf = chan->curr;
 921         if (buf == NULL)
 922                 buf = chan->next;
 923
 924         chan->curr = chan->next = chan->end = NULL;
 925
 926         if (buf != NULL) {
 927                 for ( ; buf != NULL; buf = next) {
 928                         next = buf->next;
 929
 930                         pr_debug("%s: free buffer %p, next %p\n",
 931                                __FUNCTION__, buf, buf->next);
 932
 933                         s3c2410_dma_buffdone(chan, buf, S3C2410_RES_ABORT);
 934                         s3c2410_dma_freebuf(buf);
 935                 }
 936         }
 937
 938         dbg_showregs(chan);
 939
 940         s3c2410_dma_waitforstop(chan);
 941
 942 #if 0
 943         /* should also clear interrupts, according to WinCE BSP */
 944         {
 945                 unsigned long tmp;
 946
 947                 tmp = dma_rdreg(chan, S3C2410_DMA_DCON);
 948                 tmp |= S3C2410_DCON_NORELOAD;
 949                 dma_wrreg(chan, S3C2410_DMA_DCON, tmp);
 950         }
 951 #endif
 952
 953         dbg_showregs(chan);
 954
 955         local_irq_restore(flags);
 956
 957         return 0;
 958 }
 959
 960 int
 961 s3c2410_dma_started(struct s3c2410_dma_chan *chan)
 962 {
 963         unsigned long flags;
 964
 965         local_irq_save(flags);
 966
 967         dbg_showchan(chan);
 968
 969         /* if we've only loaded one buffer onto the channel, then chec
 970          * to see if we have another, and if so, try and load it so when
 971          * the first buffer is finished, the new one will be loaded onto
 972          * the channel */
 973
 974         if (chan->next != NULL) {
 975                 if (chan->load_state == S3C2410_DMALOAD_1LOADED) {
 976
 977                         if (s3c2410_dma_waitforload(chan, __LINE__) == 0) {
 978                                 pr_debug("%s: buff not yet loaded, no more todo\n",
 979                                          __FUNCTION__);
 980                         } else {
 981                                 chan->load_state = S3C2410_DMALOAD_1RUNNING;
 982                                 s3c2410_dma_loadbuffer(chan, chan->next);
 983                         }
 984
 985                 } else if (chan->load_state == S3C2410_DMALOAD_1RUNNING) {
 986                         s3c2410_dma_loadbuffer(chan, chan->next);
 987                 }
 988         }
 989
 990
 991         local_irq_restore(flags);
 992
 993         return 0;
 994
 995 }
 996
 997 int
 998 s3c2410_dma_ctrl(dmach_t channel, enum s3c2410_chan_op op)
 999 {
1000         struct s3c2410_dma_chan *chan = lookup_dma_channel(channel);
1001
1002         if (chan == NULL)
1003                 return -EINVAL;
1004
1005         switch (op) {
1006         case S3C2410_DMAOP_START:
1007                 return s3c2410_dma_start(chan);
1008
1009         case S3C2410_DMAOP_STOP:
1010                 return s3c2410_dma_dostop(chan);
1011
1012         case S3C2410_DMAOP_PAUSE:
1013         case S3C2410_DMAOP_RESUME:
1014                 return -ENOENT;
1015
1016         case S3C2410_DMAOP_FLUSH:
1017                 return s3c2410_dma_flush(chan);
1018
1019         case S3C2410_DMAOP_STARTED:
1020                 return s3c2410_dma_started(chan);
1021
1022         case S3C2410_DMAOP_TIMEOUT:
1023                 return 0;
1024
1025         }
1026
1027         return -ENOENT;      /* unknown, don't bother */
1028 }
1029
1030 EXPORT_SYMBOL(s3c2410_dma_ctrl);
1031
1032 /* DMA configuration for each channel
1033  *
1034  * DISRCC -> source of the DMA (AHB,APB)
1035  * DISRC  -> source address of the DMA
1036  * DIDSTC -> destination of the DMA (AHB,APD)
1037  * DIDST  -> destination address of the DMA
1038 */
1039
1040 /* s3c2410_dma_config
1041  *
1042  * xfersize:     size of unit in bytes (1,2,4)
1043  * dcon:         base value of the DCONx register
1044 */
1045
1046 int s3c2410_dma_config(dmach_t channel,
1047                        int xferunit,
1048                        int dcon)
1049 {
1050         struct s3c2410_dma_chan *chan = lookup_dma_channel(channel);
1051
1052         pr_debug("%s: chan=%d, xfer_unit=%d, dcon=%08x\n",
1053                  __FUNCTION__, channel, xferunit, dcon);
1054
1055         if (chan == NULL)
1056                 return -EINVAL;
1057
1058         pr_debug("%s: Initial dcon is %08x\n", __FUNCTION__, dcon);
1059
1060         dcon |= chan->dcon & dma_sel.dcon_mask;
1061
1062         pr_debug("%s: New dcon is %08x\n", __FUNCTION__, dcon);
1063
1064         switch (xferunit) {
1065         case 1:
1066                 dcon |= S3C2410_DCON_BYTE;
1067                 break;
1068
1069         case 2:
1070                 dcon |= S3C2410_DCON_HALFWORD;
1071                 break;
1072
1073         case 4:
1074                 dcon |= S3C2410_DCON_WORD;
1075                 break;
1076
1077         default:
1078                 pr_debug("%s: bad transfer size %d\n", __FUNCTION__, xferunit);
1079                 return -EINVAL;
1080         }
1081
1082         dcon |= S3C2410_DCON_HWTRIG;
1083         dcon |= S3C2410_DCON_INTREQ;
1084
1085         pr_debug("%s: dcon now %08x\n", __FUNCTION__, dcon);
1086
1087         chan->dcon = dcon;
1088         chan->xfer_unit = xferunit;
1089
1090         return 0;
1091 }
1092
1093 EXPORT_SYMBOL(s3c2410_dma_config);
1094
1095 int s3c2410_dma_setflags(dmach_t channel, unsigned int flags)
1096 {
1097         struct s3c2410_dma_chan *chan = lookup_dma_channel(channel);
1098
1099         if (chan == NULL)
1100                 return -EINVAL;
1101
1102         pr_debug("%s: chan=%p, flags=%08x\n", __FUNCTION__, chan, flags);
1103
1104         chan->flags = flags;
1105
1106         return 0;
1107 }
1108
1109 EXPORT_SYMBOL(s3c2410_dma_setflags);
1110
1111
1112 /* do we need to protect the settings of the fields from
1113  * irq?
1114 */
1115
1116 int s3c2410_dma_set_opfn(dmach_t channel, s3c2410_dma_opfn_t rtn)
1117 {
1118         struct s3c2410_dma_chan *chan = lookup_dma_channel(channel);
1119
1120         if (chan == NULL)
1121                 return -EINVAL;
1122
1123         pr_debug("%s: chan=%p, op rtn=%p\n", __FUNCTION__, chan, rtn);
1124
1125         chan->op_fn = rtn;
1126
1127         return 0;
1128 }
1129
1130 EXPORT_SYMBOL(s3c2410_dma_set_opfn);
1131
1132 int s3c2410_dma_set_buffdone_fn(dmach_t channel, s3c2410_dma_cbfn_t rtn)
1133 {
1134         struct s3c2410_dma_chan *chan = lookup_dma_channel(channel);
1135
1136         if (chan == NULL)
1137                 return -EINVAL;
1138
1139         pr_debug("%s: chan=%p, callback rtn=%p\n", __FUNCTION__, chan, rtn);
1140
1141         chan->callback_fn = rtn;
1142
1143         return 0;
1144 }
1145
1146 EXPORT_SYMBOL(s3c2410_dma_set_buffdone_fn);
1147
1148 /* s3c2410_dma_devconfig
1149  *
1150  * configure the dma source/destination hardware type and address
1151  *
1152  * source:    S3C2410_DMASRC_HW: source is hardware
1153  *            S3C2410_DMASRC_MEM: source is memory
1154  *
1155  * hwcfg:     the value for xxxSTCn register,
1156  *            bit 0: 0=increment pointer, 1=leave pointer
1157  *            bit 1: 0=soucre is AHB, 1=soucre is APB
1158  *
1159  * devaddr:   physical address of the source
1160 */
1161
1162 int s3c2410_dma_devconfig(int channel,
1163                           enum s3c2410_dmasrc source,
1164                           int hwcfg,
1165                           unsigned long devaddr)
1166 {
1167         struct s3c2410_dma_chan *chan = lookup_dma_channel(channel);
1168
1169         if (chan == NULL)
1170                 return -EINVAL;
1171
1172         pr_debug("%s: source=%d, hwcfg=%08x, devaddr=%08lx\n",
1173                  __FUNCTION__, (int)source, hwcfg, devaddr);
1174
1175         chan->source = source;
1176         chan->dev_addr = devaddr;
1177
1178         switch (source) {
1179         case S3C2410_DMASRC_HW:
1180                 /* source is hardware */
1181                 pr_debug("%s: hw source, devaddr=%08lx, hwcfg=%d\n",
1182                          __FUNCTION__, devaddr, hwcfg);
1183                 dma_wrreg(chan, S3C2410_DMA_DISRCC, hwcfg & 3);
1184                 dma_wrreg(chan, S3C2410_DMA_DISRC,  devaddr);
1185                 dma_wrreg(chan, S3C2410_DMA_DIDSTC, (0<<1) | (0<<0));
1186
1187                 chan->addr_reg = dma_regaddr(chan, S3C2410_DMA_DIDST);
1188                 return 0;
1189
1190         case S3C2410_DMASRC_MEM:
1191                 /* source is memory */
1192                 pr_debug( "%s: mem source, devaddr=%08lx, hwcfg=%d\n",
1193                           __FUNCTION__, devaddr, hwcfg);
1194                 dma_wrreg(chan, S3C2410_DMA_DISRCC, (0<<1) | (0<<0));
1195                 dma_wrreg(chan, S3C2410_DMA_DIDST,  devaddr);
1196                 dma_wrreg(chan, S3C2410_DMA_DIDSTC, hwcfg & 3);
1197
1198                 chan->addr_reg = dma_regaddr(chan, S3C2410_DMA_DISRC);
1199                 return 0;
1200         }
1201
1202         printk(KERN_ERR "dma%d: invalid source type (%d)\n", channel, source);
1203         return -EINVAL;
1204 }
1205
1206 EXPORT_SYMBOL(s3c2410_dma_devconfig);
1207
1208 /* s3c2410_dma_getposition
1209  *
1210  * returns the current transfer points for the dma source and destination
1211 */
1212
1213 int s3c2410_dma_getposition(dmach_t channel, dma_addr_t *src, dma_addr_t *dst)
1214 {
1215         struct s3c2410_dma_chan *chan = lookup_dma_channel(channel);
1216
1217         if (chan == NULL)
1218                 return -EINVAL;
1219
1220         if (src != NULL)
1221                 *src = dma_rdreg(chan, S3C2410_DMA_DCSRC);
1222
1223         if (dst != NULL)
1224                 *dst = dma_rdreg(chan, S3C2410_DMA_DCDST);
1225
1226         return 0;
1227 }
1228
1229 EXPORT_SYMBOL(s3c2410_dma_getposition);
1230
1231
1232 /* system device class */
1233
1234 #ifdef CONFIG_PM
1235
1236 static int s3c2410_dma_suspend(struct sys_device *dev, pm_message_t state)
1237 {
1238         struct s3c2410_dma_chan *cp = container_of(dev, struct s3c2410_dma_chan, dev);
1239
1240         printk(KERN_DEBUG "suspending dma channel %d\n", cp->number);
1241
1242         if (dma_rdreg(cp, S3C2410_DMA_DMASKTRIG) & S3C2410_DMASKTRIG_ON) {
1243                 /* the dma channel is still working, which is probably
1244                  * a bad thing to do over suspend/resume. We stop the
1245                  * channel and assume that the client is either going to
1246                  * retry after resume, or that it is broken.
1247                  */
1248
1249                 printk(KERN_INFO "dma: stopping channel %d due to suspend\n",
1250                        cp->number);
1251
1252                 s3c2410_dma_dostop(cp);
1253         }
1254
1255         return 0;
1256 }
1257
1258 static int s3c2410_dma_resume(struct sys_device *dev)
1259 {
1260         return 0;
1261 }
1262
1263 #else
1264 #define s3c2410_dma_suspend NULL
1265 #define s3c2410_dma_resume  NULL
1266 #endif /* CONFIG_PM */
1267
1268 struct sysdev_class dma_sysclass = {
1269         set_kset_name("s3c24xx-dma"),
1270         .suspend        = s3c2410_dma_suspend,
1271         .resume         = s3c2410_dma_resume,
1272 };
1273
1274 /* kmem cache implementation */
1275
1276 static void s3c2410_dma_cache_ctor(void *p, struct kmem_cache *c, unsigned long f)
1277 {
1278         memset(p, 0, sizeof(struct s3c2410_dma_buf));
1279 }
1280
1281 /* initialisation code */
1282
1283 int __init s3c24xx_dma_sysclass_init(void)
1284 {
1285         int ret = sysdev_class_register(&dma_sysclass);
1286
1287         if (ret != 0)
1288                 printk(KERN_ERR "dma sysclass registration failed\n");
1289
1290         return ret;
1291 }
1292
1293 core_initcall(s3c24xx_dma_sysclass_init);
1294
1295 int __init s3c24xx_dma_sysdev_register(void)
1296 {
1297         struct s3c2410_dma_chan *cp = s3c2410_chans;
1298         int channel, ret;
1299
1300         for (channel = 0; channel < dma_channels; cp++, channel++) {
1301                 cp->dev.cls = &dma_sysclass;
1302                 cp->dev.id  = channel;
1303                 ret = sysdev_register(&cp->dev);
1304
1305                 if (ret) {
1306                         printk(KERN_ERR "error registering dev for dma %d\n",
1307                                channel);
1308                         return ret;
1309                 }
1310         }
1311
1312         return 0;
1313 }
1314
1315 late_initcall(s3c24xx_dma_sysdev_register);
1316
1317 int __init s3c24xx_dma_init(unsigned int channels, unsigned int irq,
1318                             unsigned int stride)
1319 {
1320         struct s3c2410_dma_chan *cp;
1321         int channel;
1322         int ret;
1323
1324         printk("S3C24XX DMA Driver, (c) 2003-2004,2006 Simtec Electronics\n");
1325
1326         dma_channels = channels;
1327
1328         dma_base = ioremap(S3C24XX_PA_DMA, stride * channels);
1329         if (dma_base == NULL) {
1330                 printk(KERN_ERR "dma failed to remap register block\n");
1331                 return -ENOMEM;
1332         }
1333
1334         dma_kmem = kmem_cache_create("dma_desc",
1335                                      sizeof(struct s3c2410_dma_buf), 0,
1336                                      SLAB_HWCACHE_ALIGN,
1337                                      s3c2410_dma_cache_ctor, NULL);
1338
1339         if (dma_kmem == NULL) {
1340                 printk(KERN_ERR "dma failed to make kmem cache\n");
1341                 ret = -ENOMEM;
1342                 goto err;
1343         }
1344
1345         for (channel = 0; channel < channels;  channel++) {
1346                 cp = &s3c2410_chans[channel];
1347
1348                 memset(cp, 0, sizeof(struct s3c2410_dma_chan));
1349
1350                 /* dma channel irqs are in order.. */
1351                 cp->number = channel;
1352                 cp->irq    = channel + irq;
1353                 cp->regs   = dma_base + (channel * stride);
1354
1355                 /* point current stats somewhere */
1356                 cp->stats  = &cp->stats_store;
1357                 cp->stats_store.timeout_shortest = LONG_MAX;
1358
1359                 /* basic channel configuration */
1360
1361                 cp->load_timeout = 1<<18;
1362
1363                 printk("DMA channel %d at %p, irq %d\n",
1364                        cp->number, cp->regs, cp->irq);
1365         }
1366
1367         return 0;
1368
1369  err:
1370         kmem_cache_destroy(dma_kmem);
1371         iounmap(dma_base);
1372         dma_base = NULL;
1373         return ret;
1374 }
1375
1376 int s3c2410_dma_init(void)
1377 {
1378         return s3c24xx_dma_init(4, IRQ_DMA0, 0x40);
1379 }
1380
1381 static inline int is_channel_valid(unsigned int channel)
1382 {
1383         return (channel & DMA_CH_VALID);
1384 }
1385
1386 static struct s3c24xx_dma_order *dma_order;
1387
1388
1389 /* s3c2410_dma_map_channel()
1390  *
1391  * turn the virtual channel number into a real, and un-used hardware
1392  * channel.
1393  *
1394  * first, try the dma ordering given to us by either the relevant
1395  * dma code, or the board. Then just find the first usable free
1396  * channel
1397 */
1398
1399 struct s3c2410_dma_chan *s3c2410_dma_map_channel(int channel)
1400 {
1401         struct s3c24xx_dma_order_ch *ord = NULL;
1402         struct s3c24xx_dma_map *ch_map;
1403         struct s3c2410_dma_chan *dmach;
1404         int ch;
1405
1406         if (dma_sel.map == NULL || channel > dma_sel.map_size)
1407                 return NULL;
1408
1409         ch_map = dma_sel.map + channel;
1410
1411         /* first, try the board mapping */
1412
1413         if (dma_order) {
1414                 ord = &dma_order->channels[channel];
1415
1416                 for (ch = 0; ch < dma_channels; ch++) {
1417                         if (!is_channel_valid(ord->list[ch]))
1418                                 continue;
1419
1420                         if (s3c2410_chans[ord->list[ch]].in_use == 0) {
1421                                 ch = ord->list[ch] & ~DMA_CH_VALID;
1422                                 goto found;
1423                         }
1424                 }
1425
1426                 if (ord->flags & DMA_CH_NEVER)
1427                         return NULL;
1428         }
1429
1430         /* second, search the channel map for first free */
1431
1432         for (ch = 0; ch < dma_channels; ch++) {
1433                 if (!is_channel_valid(ch_map->channels[ch]))
1434                         continue;
1435
1436                 if (s3c2410_chans[ch].in_use == 0) {
1437                         printk("mapped channel %d to %d\n", channel, ch);
1438                         break;
1439                 }
1440         }
1441
1442         if (ch >= dma_channels)
1443                 return NULL;
1444
1445         /* update our channel mapping */
1446
1447  found:
1448         dmach = &s3c2410_chans[ch];
1449         dma_chan_map[channel] = dmach;
1450
1451         /* select the channel */
1452
1453         (dma_sel.select)(dmach, ch_map);
1454
1455         return dmach;
1456 }
1457
1458 static int s3c24xx_dma_check_entry(struct s3c24xx_dma_map *map, int ch)
1459 {
1460         return 0;
1461 }
1462
1463 int __init s3c24xx_dma_init_map(struct s3c24xx_dma_selection *sel)
1464 {
1465         struct s3c24xx_dma_map *nmap;
1466         size_t map_sz = sizeof(*nmap) * sel->map_size;
1467         int ptr;
1468
1469         nmap = kmalloc(map_sz, GFP_KERNEL);
1470         if (nmap == NULL)
1471                 return -ENOMEM;
1472
1473         memcpy(nmap, sel->map, map_sz);
1474         memcpy(&dma_sel, sel, sizeof(*sel));
1475
1476         dma_sel.map = nmap;
1477
1478         for (ptr = 0; ptr < sel->map_size; ptr++)
1479                 s3c24xx_dma_check_entry(nmap+ptr, ptr);
1480
1481         return 0;
1482 }
1483
1484 int __init s3c24xx_dma_order_set(struct s3c24xx_dma_order *ord)
1485 {
1486         struct s3c24xx_dma_order *nord = dma_order;
1487
1488         if (nord == NULL)
1489                 nord = kmalloc(sizeof(struct s3c24xx_dma_order), GFP_KERNEL);
1490
1491         if (nord == NULL) {
1492                 printk(KERN_ERR "no memory to store dma channel order\n");
1493                 return -ENOMEM;
1494         }
1495
1496         dma_order = nord;
1497         memcpy(nord, ord, sizeof(struct s3c24xx_dma_order));
1498         return 0;
1499 }