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   1 /* linux/arch/arm/mach-bast/dma.c
   2  *
   3  * (c) 2003-2005 Simtec Electronics
   4  *      Ben Dooks <ben@simtec.co.uk>
   5  *
   6  * S3C2410 DMA core
   7  *
   8  * http://www.simtec.co.uk/products/EB2410ITX/
   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  * Changelog:
  15  *  27-Feb-2005 BJD  Added kmem cache for dma descriptors
  16  *  18-Nov-2004 BJD  Removed error for loading onto stopped channel
  17  *  10-Nov-2004 BJD  Ensure all external symbols exported for modules
  18  *  10-Nov-2004 BJD  Use sys_device and sysdev_class for power management
  19  *  08-Aug-2004 BJD  Apply rmk's suggestions
  20  *  21-Jul-2004 BJD  Ported to linux 2.6
  21  *  12-Jul-2004 BJD  Finished re-write and change of API
  22  *  06-Jul-2004 BJD  Rewrote dma code to try and cope with various problems
  23  *  23-May-2003 BJD  Created file
  24  *  19-Aug-2003 BJD  Cleanup, header fix, added URL
  25  *
  26  * This file is based on the Sangwook Lee/Samsung patches, re-written due
  27  * to various ommisions from the code (such as flexible dma configuration)
  28  * for use with the BAST system board.
  29  *
  30  * The re-write is pretty much complete, and should be good enough for any
  31  * possible DMA function
  32  */
  33
  34
  35 #ifdef CONFIG_S3C2410_DMA_DEBUG
  36 #define DEBUG
  37 #endif
  38
  39 #include <linux/module.h>
  40 #include <linux/init.h>
  41 #include <linux/sched.h>
  42 #include <linux/spinlock.h>
  43 #include <linux/interrupt.h>
  44 #include <linux/sysdev.h>
  45 #include <linux/slab.h>
  46 #include <linux/errno.h>
  47 #include <linux/delay.h>
  48
  49 #include <asm/system.h>
  50 #include <asm/irq.h>
  51 #include <asm/hardware.h>
  52 #include <asm/io.h>
  53 #include <asm/dma.h>
  54
  55 #include <asm/mach/dma.h>
  56 #include <asm/arch/map.h>
  57
  58 /* io map for dma */
  59 static void __iomem *dma_base;
  60 static kmem_cache_t *dma_kmem;
  61
  62 /* dma channel state information */
  63 s3c2410_dma_chan_t s3c2410_chans[S3C2410_DMA_CHANNELS];
  64
  65 /* debugging functions */
  66
  67 #define BUF_MAGIC (0xcafebabe)
  68
  69 #define dmawarn(fmt...) printk(KERN_DEBUG fmt)
  70
  71 #define dma_regaddr(chan, reg) ((chan)->regs + (reg))
  72
  73 #if 1
  74 #define dma_wrreg(chan, reg, val) writel((val), (chan)->regs + (reg))
  75 #else
  76 static inline void
  77 dma_wrreg(s3c2410_dma_chan_t *chan, int reg, unsigned long val)
  78 {
  79         pr_debug("writing %08x to register %08x\n",(unsigned int)val,reg);
  80         writel(val, dma_regaddr(chan, reg));
  81 }
  82
  83 #endif
  84
  85 #define dma_rdreg(chan, reg) readl((chan)->regs + (reg))
  86
  87 /* captured register state for debug */
  88
  89 struct s3c2410_dma_regstate {
  90         unsigned long         dcsrc;
  91         unsigned long         disrc;
  92         unsigned long         dstat;
  93         unsigned long         dcon;
  94         unsigned long         dmsktrig;
  95 };
  96
  97 #ifdef CONFIG_S3C2410_DMA_DEBUG
  98
  99 /* dmadbg_showregs
 100  *
 101  * simple debug routine to print the current state of the dma registers
 102 */
 103
 104 static void
 105 dmadbg_capture(s3c2410_dma_chan_t *chan, struct s3c2410_dma_regstate *regs)
 106 {
 107         regs->dcsrc    = dma_rdreg(chan, S3C2410_DMA_DCSRC);
 108         regs->disrc    = dma_rdreg(chan, S3C2410_DMA_DISRC);
 109         regs->dstat    = dma_rdreg(chan, S3C2410_DMA_DSTAT);
 110         regs->dcon     = dma_rdreg(chan, S3C2410_DMA_DCON);
 111         regs->dmsktrig = dma_rdreg(chan, S3C2410_DMA_DMASKTRIG);
 112 }
 113
 114 static void
 115 dmadbg_dumpregs(const char *fname, int line, s3c2410_dma_chan_t *chan,
 116                  struct s3c2410_dma_regstate *regs)
 117 {
 118         printk(KERN_DEBUG "dma%d: %s:%d: DCSRC=%08lx, DISRC=%08lx, DSTAT=%08lx DMT=%02lx, DCON=%08lx\n",
 119                chan->number, fname, line,
 120                regs->dcsrc, regs->disrc, regs->dstat, regs->dmsktrig,
 121                regs->dcon);
 122 }
 123
 124 static void
 125 dmadbg_showchan(const char *fname, int line, s3c2410_dma_chan_t *chan)
 126 {
 127         struct s3c2410_dma_regstate state;
 128
 129         dmadbg_capture(chan, &state);
 130
 131         printk(KERN_DEBUG "dma%d: %s:%d: ls=%d, cur=%p, %p %p\n",
 132                chan->number, fname, line, chan->load_state,
 133                chan->curr, chan->next, chan->end);
 134
 135         dmadbg_dumpregs(fname, line, chan, &state);
 136 }
 137
 138 static void
 139 dmadbg_showregs(const char *fname, int line, s3c2410_dma_chan_t *chan)
 140 {
 141         struct s3c2410_dma_regstate state;
 142
 143         dmadbg_capture(chan, &state);
 144         dmadbg_dumpregs(fname, line, chan, &state);
 145 }
 146
 147 #define dbg_showregs(chan) dmadbg_showregs(__FUNCTION__, __LINE__, (chan))
 148 #define dbg_showchan(chan) dmadbg_showchan(__FUNCTION__, __LINE__, (chan))
 149 #else
 150 #define dbg_showregs(chan) do { } while(0)
 151 #define dbg_showchan(chan) do { } while(0)
 152 #endif /* CONFIG_S3C2410_DMA_DEBUG */
 153
 154 #define check_channel(chan) \
 155   do { if ((chan) >= S3C2410_DMA_CHANNELS) { \
 156     printk(KERN_ERR "%s: invalid channel %d\n", __FUNCTION__, (chan)); \
 157     return -EINVAL; \
 158   } } while(0)
 159
 160
 161 /* s3c2410_dma_stats_timeout
 162  *
 163  * Update DMA stats from timeout info
 164 */
 165
 166 static void
 167 s3c2410_dma_stats_timeout(s3c2410_dma_stats_t *stats, int val)
 168 {
 169         if (stats == NULL)
 170                 return;
 171
 172         if (val > stats->timeout_longest)
 173                 stats->timeout_longest = val;
 174         if (val < stats->timeout_shortest)
 175                 stats->timeout_shortest = val;
 176
 177         stats->timeout_avg += val;
 178 }
 179
 180 /* s3c2410_dma_waitforload
 181  *
 182  * wait for the DMA engine to load a buffer, and update the state accordingly
 183 */
 184
 185 static int
 186 s3c2410_dma_waitforload(s3c2410_dma_chan_t *chan, int line)
 187 {
 188         int timeout = chan->load_timeout;
 189         int took;
 190
 191         if (chan->load_state != S3C2410_DMALOAD_1LOADED) {
 192                 printk(KERN_ERR "dma%d: s3c2410_dma_waitforload() called in loadstate %d from line %d\n", chan->number, chan->load_state, line);
 193                 return 0;
 194         }
 195
 196         if (chan->stats != NULL)
 197                 chan->stats->loads++;
 198
 199         while (--timeout > 0) {
 200                 if ((dma_rdreg(chan, S3C2410_DMA_DSTAT) << (32-20)) != 0) {
 201                         took = chan->load_timeout - timeout;
 202
 203                         s3c2410_dma_stats_timeout(chan->stats, took);
 204
 205                         switch (chan->load_state) {
 206                         case S3C2410_DMALOAD_1LOADED:
 207                                 chan->load_state = S3C2410_DMALOAD_1RUNNING;
 208                                 break;
 209
 210                         default:
 211                                 printk(KERN_ERR "dma%d: unknown load_state in s3c2410_dma_waitforload() %d\n", chan->number, chan->load_state);
 212                         }
 213
 214                         return 1;
 215                 }
 216         }
 217
 218         if (chan->stats != NULL) {
 219                 chan->stats->timeout_failed++;
 220         }
 221
 222         return 0;
 223 }
 224
 225
 226
 227 /* s3c2410_dma_loadbuffer
 228  *
 229  * load a buffer, and update the channel state
 230 */
 231
 232 static inline int
 233 s3c2410_dma_loadbuffer(s3c2410_dma_chan_t *chan,
 234                        s3c2410_dma_buf_t *buf)
 235 {
 236         unsigned long reload;
 237
 238         pr_debug("s3c2410_chan_loadbuffer: loading buff %p (0x%08lx,0x%06x)\n",
 239                  buf, (unsigned long)buf->data, buf->size);
 240
 241         if (buf == NULL) {
 242                 dmawarn("buffer is NULL\n");
 243                 return -EINVAL;
 244         }
 245
 246         /* check the state of the channel before we do anything */
 247
 248         if (chan->load_state == S3C2410_DMALOAD_1LOADED) {
 249                 dmawarn("load_state is S3C2410_DMALOAD_1LOADED\n");
 250         }
 251
 252         if (chan->load_state == S3C2410_DMALOAD_1LOADED_1RUNNING) {
 253                 dmawarn("state is S3C2410_DMALOAD_1LOADED_1RUNNING\n");
 254         }
 255
 256         /* it would seem sensible if we are the last buffer to not bother
 257          * with the auto-reload bit, so that the DMA engine will not try
 258          * and load another transfer after this one has finished...
 259          */
 260         if (chan->load_state == S3C2410_DMALOAD_NONE) {
 261                 pr_debug("load_state is none, checking for noreload (next=%p)\n",
 262                          buf->next);
 263                 reload = (buf->next == NULL) ? S3C2410_DCON_NORELOAD : 0;
 264         } else {
 265                 //pr_debug("load_state is %d => autoreload\n", chan->load_state);
 266                 reload = S3C2410_DCON_AUTORELOAD;
 267         }
 268
 269         if ((buf->data & 0xf0000000) != 0x30000000) {
 270                 dmawarn("dmaload: buffer is %p\n", (void *)buf->data);
 271         }
 272
 273         writel(buf->data, chan->addr_reg);
 274
 275         dma_wrreg(chan, S3C2410_DMA_DCON,
 276                   chan->dcon | reload | (buf->size/chan->xfer_unit));
 277
 278         chan->next = buf->next;
 279
 280         /* update the state of the channel */
 281
 282         switch (chan->load_state) {
 283         case S3C2410_DMALOAD_NONE:
 284                 chan->load_state = S3C2410_DMALOAD_1LOADED;
 285                 break;
 286
 287         case S3C2410_DMALOAD_1RUNNING:
 288                 chan->load_state = S3C2410_DMALOAD_1LOADED_1RUNNING;
 289                 break;
 290
 291         default:
 292                 dmawarn("dmaload: unknown state %d in loadbuffer\n",
 293                         chan->load_state);
 294                 break;
 295         }
 296
 297         return 0;
 298 }
 299
 300 /* s3c2410_dma_call_op
 301  *
 302  * small routine to call the op routine with the given op if it has been
 303  * registered
 304 */
 305
 306 static void
 307 s3c2410_dma_call_op(s3c2410_dma_chan_t *chan, s3c2410_chan_op_t op)
 308 {
 309         if (chan->op_fn != NULL) {
 310                 (chan->op_fn)(chan, op);
 311         }
 312 }
 313
 314 /* s3c2410_dma_buffdone
 315  *
 316  * small wrapper to check if callback routine needs to be called, and
 317  * if so, call it
 318 */
 319
 320 static inline void
 321 s3c2410_dma_buffdone(s3c2410_dma_chan_t *chan, s3c2410_dma_buf_t *buf,
 322                      s3c2410_dma_buffresult_t result)
 323 {
 324         pr_debug("callback_fn=%p, buf=%p, id=%p, size=%d, result=%d\n",
 325                  chan->callback_fn, buf, buf->id, buf->size, result);
 326
 327         if (chan->callback_fn != NULL) {
 328                 (chan->callback_fn)(chan, buf->id, buf->size, result);
 329         }
 330 }
 331
 332 /* s3c2410_dma_start
 333  *
 334  * start a dma channel going
 335 */
 336
 337 static int s3c2410_dma_start(s3c2410_dma_chan_t *chan)
 338 {
 339         unsigned long tmp;
 340         unsigned long flags;
 341
 342         pr_debug("s3c2410_start_dma: channel=%d\n", chan->number);
 343
 344         local_irq_save(flags);
 345
 346         if (chan->state == S3C2410_DMA_RUNNING) {
 347                 pr_debug("s3c2410_start_dma: already running (%d)\n", chan->state);
 348                 local_irq_restore(flags);
 349                 return 0;
 350         }
 351
 352         chan->state = S3C2410_DMA_RUNNING;
 353
 354         /* check wether there is anything to load, and if not, see
 355          * if we can find anything to load
 356          */
 357
 358         if (chan->load_state == S3C2410_DMALOAD_NONE) {
 359                 if (chan->next == NULL) {
 360                         printk(KERN_ERR "dma%d: channel has nothing loaded\n",
 361                                chan->number);
 362                         chan->state = S3C2410_DMA_IDLE;
 363                         local_irq_restore(flags);
 364                         return -EINVAL;
 365                 }
 366
 367                 s3c2410_dma_loadbuffer(chan, chan->next);
 368         }
 369
 370         dbg_showchan(chan);
 371
 372         /* enable the channel */
 373
 374         if (!chan->irq_enabled) {
 375                 enable_irq(chan->irq);
 376                 chan->irq_enabled = 1;
 377         }
 378
 379         /* start the channel going */
 380
 381         tmp = dma_rdreg(chan, S3C2410_DMA_DMASKTRIG);
 382         tmp &= ~S3C2410_DMASKTRIG_STOP;
 383         tmp |= S3C2410_DMASKTRIG_ON;
 384         dma_wrreg(chan, S3C2410_DMA_DMASKTRIG, tmp);
 385
 386         pr_debug("dma%d: %08lx to DMASKTRIG\n", chan->number, tmp);
 387
 388 #if 0
 389         /* the dma buffer loads should take care of clearing the AUTO
 390          * reloading feature */
 391         tmp = dma_rdreg(chan, S3C2410_DMA_DCON);
 392         tmp &= ~S3C2410_DCON_NORELOAD;
 393         dma_wrreg(chan, S3C2410_DMA_DCON, tmp);
 394 #endif
 395
 396         s3c2410_dma_call_op(chan, S3C2410_DMAOP_START);
 397
 398         dbg_showchan(chan);
 399
 400         /* if we've only loaded one buffer onto the channel, then chec
 401          * to see if we have another, and if so, try and load it so when
 402          * the first buffer is finished, the new one will be loaded onto
 403          * the channel */
 404
 405         if (chan->next != NULL) {
 406                 if (chan->load_state == S3C2410_DMALOAD_1LOADED) {
 407
 408                         if (s3c2410_dma_waitforload(chan, __LINE__) == 0) {
 409                                 pr_debug("%s: buff not yet loaded, no more todo\n",
 410                                          __FUNCTION__);
 411                         } else {
 412                                 chan->load_state = S3C2410_DMALOAD_1RUNNING;
 413                                 s3c2410_dma_loadbuffer(chan, chan->next);
 414                         }
 415
 416                 } else if (chan->load_state == S3C2410_DMALOAD_1RUNNING) {
 417                         s3c2410_dma_loadbuffer(chan, chan->next);
 418                 }
 419         }
 420
 421
 422         local_irq_restore(flags);
 423
 424         return 0;
 425 }
 426
 427 /* s3c2410_dma_canload
 428  *
 429  * work out if we can queue another buffer into the DMA engine
 430 */
 431
 432 static int
 433 s3c2410_dma_canload(s3c2410_dma_chan_t *chan)
 434 {
 435         if (chan->load_state == S3C2410_DMALOAD_NONE ||
 436             chan->load_state == S3C2410_DMALOAD_1RUNNING)
 437                 return 1;
 438
 439         return 0;
 440 }
 441
 442
 443 /* s3c2410_dma_enqueue
 444  *
 445  * queue an given buffer for dma transfer.
 446  *
 447  * id         the device driver's id information for this buffer
 448  * data       the physical address of the buffer data
 449  * size       the size of the buffer in bytes
 450  *
 451  * If the channel is not running, then the flag S3C2410_DMAF_AUTOSTART
 452  * is checked, and if set, the channel is started. If this flag isn't set,
 453  * then an error will be returned.
 454  *
 455  * It is possible to queue more than one DMA buffer onto a channel at
 456  * once, and the code will deal with the re-loading of the next buffer
 457  * when necessary.
 458 */
 459
 460 int s3c2410_dma_enqueue(unsigned int channel, void *id,
 461                         dma_addr_t data, int size)
 462 {
 463         s3c2410_dma_chan_t *chan = &s3c2410_chans[channel];
 464         s3c2410_dma_buf_t *buf;
 465         unsigned long flags;
 466
 467         check_channel(channel);
 468
 469         pr_debug("%s: id=%p, data=%08x, size=%d\n",
 470                  __FUNCTION__, id, (unsigned int)data, size);
 471
 472         buf = kmem_cache_alloc(dma_kmem, GFP_ATOMIC);
 473         if (buf == NULL) {
 474                 pr_debug("%s: out of memory (%ld alloc)\n",
 475                          __FUNCTION__, (long)sizeof(*buf));
 476                 return -ENOMEM;
 477         }
 478
 479         //pr_debug("%s: new buffer %p\n", __FUNCTION__, buf);
 480         //dbg_showchan(chan);
 481
 482         buf->next  = NULL;
 483         buf->data  = buf->ptr = data;
 484         buf->size  = size;
 485         buf->id    = id;
 486         buf->magic = BUF_MAGIC;
 487
 488         local_irq_save(flags);
 489
 490         if (chan->curr == NULL) {
 491                 /* we've got nothing loaded... */
 492                 pr_debug("%s: buffer %p queued onto empty channel\n",
 493                          __FUNCTION__, buf);
 494
 495                 chan->curr = buf;
 496                 chan->end  = buf;
 497                 chan->next = NULL;
 498         } else {
 499                 pr_debug("dma%d: %s: buffer %p queued onto non-empty channel\n",
 500                          chan->number, __FUNCTION__, buf);
 501
 502                 if (chan->end == NULL)
 503                         pr_debug("dma%d: %s: %p not empty, and chan->end==NULL?\n",
 504                                  chan->number, __FUNCTION__, chan);
 505
 506                 chan->end->next = buf;
 507                 chan->end = buf;
 508         }
 509
 510         /* if necessary, update the next buffer field */
 511         if (chan->next == NULL)
 512                 chan->next = buf;
 513
 514         /* check to see if we can load a buffer */
 515         if (chan->state == S3C2410_DMA_RUNNING) {
 516                 if (chan->load_state == S3C2410_DMALOAD_1LOADED && 1) {
 517                         if (s3c2410_dma_waitforload(chan, __LINE__) == 0) {
 518                                 printk(KERN_ERR "dma%d: loadbuffer:"
 519                                        "timeout loading buffer\n",
 520                                        chan->number);
 521                                 dbg_showchan(chan);
 522                                 local_irq_restore(flags);
 523                                 return -EINVAL;
 524                         }
 525                 }
 526
 527                 while (s3c2410_dma_canload(chan) && chan->next != NULL) {
 528                         s3c2410_dma_loadbuffer(chan, chan->next);
 529                 }
 530         } else if (chan->state == S3C2410_DMA_IDLE) {
 531                 if (chan->flags & S3C2410_DMAF_AUTOSTART) {
 532                         s3c2410_dma_ctrl(chan->number, S3C2410_DMAOP_START);
 533                 }
 534         }
 535
 536         local_irq_restore(flags);
 537         return 0;
 538 }
 539
 540 EXPORT_SYMBOL(s3c2410_dma_enqueue);
 541
 542 static inline void
 543 s3c2410_dma_freebuf(s3c2410_dma_buf_t *buf)
 544 {
 545         int magicok = (buf->magic == BUF_MAGIC);
 546
 547         buf->magic = -1;
 548
 549         if (magicok) {
 550                 kmem_cache_free(dma_kmem, buf);
 551         } else {
 552                 printk("s3c2410_dma_freebuf: buff %p with bad magic\n", buf);
 553         }
 554 }
 555
 556 /* s3c2410_dma_lastxfer
 557  *
 558  * called when the system is out of buffers, to ensure that the channel
 559  * is prepared for shutdown.
 560 */
 561
 562 static inline void
 563 s3c2410_dma_lastxfer(s3c2410_dma_chan_t *chan)
 564 {
 565         pr_debug("dma%d: s3c2410_dma_lastxfer: load_state %d\n",
 566                  chan->number, chan->load_state);
 567
 568         switch (chan->load_state) {
 569         case S3C2410_DMALOAD_NONE:
 570                 break;
 571
 572         case S3C2410_DMALOAD_1LOADED:
 573                 if (s3c2410_dma_waitforload(chan, __LINE__) == 0) {
 574                                 /* flag error? */
 575                         printk(KERN_ERR "dma%d: timeout waiting for load (%s)\n",
 576                                chan->number, __FUNCTION__);
 577                         return;
 578                 }
 579                 break;
 580
 581         case S3C2410_DMALOAD_1LOADED_1RUNNING:
 582                 /* I belive in this case we do not have anything to do
 583                  * until the next buffer comes along, and we turn off the
 584                  * reload */
 585                 return;
 586
 587         default:
 588                 pr_debug("dma%d: lastxfer: unhandled load_state %d with no next\n",
 589                          chan->number, chan->load_state);
 590                 return;
 591
 592         }
 593
 594         /* hopefully this'll shut the damned thing up after the transfer... */
 595         dma_wrreg(chan, S3C2410_DMA_DCON, chan->dcon | S3C2410_DCON_NORELOAD);
 596 }
 597
 598
 599 #define dmadbg2(x...)
 600
 601 static irqreturn_t
 602 s3c2410_dma_irq(int irq, void *devpw, struct pt_regs *regs)
 603 {
 604         s3c2410_dma_chan_t *chan = (s3c2410_dma_chan_t *)devpw;
 605         s3c2410_dma_buf_t  *buf;
 606
 607         buf = chan->curr;
 608
 609         dbg_showchan(chan);
 610
 611         /* modify the channel state */
 612
 613         switch (chan->load_state) {
 614         case S3C2410_DMALOAD_1RUNNING:
 615                 /* TODO - if we are running only one buffer, we probably
 616                  * want to reload here, and then worry about the buffer
 617                  * callback */
 618
 619                 chan->load_state = S3C2410_DMALOAD_NONE;
 620                 break;
 621
 622         case S3C2410_DMALOAD_1LOADED:
 623                 /* iirc, we should go back to NONE loaded here, we
 624                  * had a buffer, and it was never verified as being
 625                  * loaded.
 626                  */
 627
 628                 chan->load_state = S3C2410_DMALOAD_NONE;
 629                 break;
 630
 631         case S3C2410_DMALOAD_1LOADED_1RUNNING:
 632                 /* we'll worry about checking to see if another buffer is
 633                  * ready after we've called back the owner. This should
 634                  * ensure we do not wait around too long for the DMA
 635                  * engine to start the next transfer
 636                  */
 637
 638                 chan->load_state = S3C2410_DMALOAD_1LOADED;
 639                 break;
 640
 641         case S3C2410_DMALOAD_NONE:
 642                 printk(KERN_ERR "dma%d: IRQ with no loaded buffer?\n",
 643                        chan->number);
 644                 break;
 645
 646         default:
 647                 printk(KERN_ERR "dma%d: IRQ in invalid load_state %d\n",
 648                        chan->number, chan->load_state);
 649                 break;
 650         }
 651
 652         if (buf != NULL) {
 653                 /* update the chain to make sure that if we load any more
 654                  * buffers when we call the callback function, things should
 655                  * work properly */
 656
 657                 chan->curr = buf->next;
 658                 buf->next  = NULL;
 659
 660                 if (buf->magic != BUF_MAGIC) {
 661                         printk(KERN_ERR "dma%d: %s: buf %p incorrect magic\n",
 662                                chan->number, __FUNCTION__, buf);
 663                         return IRQ_HANDLED;
 664                 }
 665
 666                 s3c2410_dma_buffdone(chan, buf, S3C2410_RES_OK);
 667
 668                 /* free resouces */
 669                 s3c2410_dma_freebuf(buf);
 670         } else {
 671         }
 672
 673         /* only reload if the channel is still running... our buffer done
 674          * routine may have altered the state by requesting the dma channel
 675          * to stop or shutdown... */
 676
 677         /* todo: check that when the channel is shut-down from inside this
 678          * function, we cope with unsetting reload, etc */
 679
 680         if (chan->next != NULL && chan->state != S3C2410_DMA_IDLE) {
 681                 unsigned long flags;
 682
 683                 switch (chan->load_state) {
 684                 case S3C2410_DMALOAD_1RUNNING:
 685                         /* don't need to do anything for this state */
 686                         break;
 687
 688                 case S3C2410_DMALOAD_NONE:
 689                         /* can load buffer immediately */
 690                         break;
 691
 692                 case S3C2410_DMALOAD_1LOADED:
 693                         if (s3c2410_dma_waitforload(chan, __LINE__) == 0) {
 694                                 /* flag error? */
 695                                 printk(KERN_ERR "dma%d: timeout waiting for load (%s)\n",
 696                                        chan->number, __FUNCTION__);
 697                                 return IRQ_HANDLED;
 698                         }
 699
 700                         break;
 701
 702                 case S3C2410_DMALOAD_1LOADED_1RUNNING:
 703                         goto no_load;
 704
 705                 default:
 706                         printk(KERN_ERR "dma%d: unknown load_state in irq, %d\n",
 707                                chan->number, chan->load_state);
 708                         return IRQ_HANDLED;
 709                 }
 710
 711                 local_irq_save(flags);
 712                 s3c2410_dma_loadbuffer(chan, chan->next);
 713                 local_irq_restore(flags);
 714         } else {
 715                 s3c2410_dma_lastxfer(chan);
 716
 717                 /* see if we can stop this channel.. */
 718                 if (chan->load_state == S3C2410_DMALOAD_NONE) {
 719                         pr_debug("dma%d: end of transfer, stopping channel (%ld)\n",
 720                                  chan->number, jiffies);
 721                         s3c2410_dma_ctrl(chan->number, S3C2410_DMAOP_STOP);
 722                 }
 723         }
 724
 725  no_load:
 726         return IRQ_HANDLED;
 727 }
 728
 729 /* s3c2410_request_dma
 730  *
 731  * get control of an dma channel
 732 */
 733
 734 int s3c2410_dma_request(unsigned int channel, s3c2410_dma_client_t *client,
 735                         void *dev)
 736 {
 737         s3c2410_dma_chan_t *chan = &s3c2410_chans[channel];
 738         unsigned long flags;
 739         int err;
 740
 741         pr_debug("dma%d: s3c2410_request_dma: client=%s, dev=%p\n",
 742                  channel, client->name, dev);
 743
 744         check_channel(channel);
 745
 746         local_irq_save(flags);
 747
 748         dbg_showchan(chan);
 749
 750         if (chan->in_use) {
 751                 if (client != chan->client) {
 752                         printk(KERN_ERR "dma%d: already in use\n", channel);
 753                         local_irq_restore(flags);
 754                         return -EBUSY;
 755                 } else {
 756                         printk(KERN_ERR "dma%d: client already has channel\n", channel);
 757                 }
 758         }
 759
 760         chan->client = client;
 761         chan->in_use = 1;
 762
 763         if (!chan->irq_claimed) {
 764                 pr_debug("dma%d: %s : requesting irq %d\n",
 765                          channel, __FUNCTION__, chan->irq);
 766
 767                 chan->irq_claimed = 1;
 768                 local_irq_restore(flags);
 769
 770                 err = request_irq(chan->irq, s3c2410_dma_irq, IRQF_DISABLED,
 771                                   client->name, (void *)chan);
 772
 773                 local_irq_save(flags);
 774
 775                 if (err) {
 776                         chan->in_use = 0;
 777                         chan->irq_claimed = 0;
 778                         local_irq_restore(flags);
 779
 780                         printk(KERN_ERR "%s: cannot get IRQ %d for DMA %d\n",
 781                                client->name, chan->irq, chan->number);
 782                         return err;
 783                 }
 784
 785                 chan->irq_enabled = 1;
 786         }
 787
 788         local_irq_restore(flags);
 789
 790         /* need to setup */
 791
 792         pr_debug("%s: channel initialised, %p\n", __FUNCTION__, chan);
 793
 794         return 0;
 795 }
 796
 797 EXPORT_SYMBOL(s3c2410_dma_request);
 798
 799 /* s3c2410_dma_free
 800  *
 801  * release the given channel back to the system, will stop and flush
 802  * any outstanding transfers, and ensure the channel is ready for the
 803  * next claimant.
 804  *
 805  * Note, although a warning is currently printed if the freeing client
 806  * info is not the same as the registrant's client info, the free is still
 807  * allowed to go through.
 808 */
 809
 810 int s3c2410_dma_free(dmach_t channel, s3c2410_dma_client_t *client)
 811 {
 812         s3c2410_dma_chan_t *chan = &s3c2410_chans[channel];
 813         unsigned long flags;
 814
 815         check_channel(channel);
 816
 817         local_irq_save(flags);
 818
 819
 820         if (chan->client != client) {
 821                 printk(KERN_WARNING "dma%d: possible free from different client (channel %p, passed %p)\n",
 822                        channel, chan->client, client);
 823         }
 824
 825         /* sort out stopping and freeing the channel */
 826
 827         if (chan->state != S3C2410_DMA_IDLE) {
 828                 pr_debug("%s: need to stop dma channel %p\n",
 829                        __FUNCTION__, chan);
 830
 831                 /* possibly flush the channel */
 832                 s3c2410_dma_ctrl(channel, S3C2410_DMAOP_STOP);
 833         }
 834
 835         chan->client = NULL;
 836         chan->in_use = 0;
 837
 838         if (chan->irq_claimed)
 839                 free_irq(chan->irq, (void *)chan);
 840         chan->irq_claimed = 0;
 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(s3c2410_dma_chan_t *chan)
 850 {
 851         unsigned long tmp;
 852         unsigned long flags;
 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(s3c2410_dma_chan_t *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(s3c2410_dma_chan_t *chan)
 905 {
 906         s3c2410_dma_buf_t *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(s3c2410_dma_chan_t *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, s3c2410_chan_op_t op)
 999 {
1000         s3c2410_dma_chan_t *chan = &s3c2410_chans[channel];
1001
1002         check_channel(channel);
1003
1004         switch (op) {
1005         case S3C2410_DMAOP_START:
1006                 return s3c2410_dma_start(chan);
1007
1008         case S3C2410_DMAOP_STOP:
1009                 return s3c2410_dma_dostop(chan);
1010
1011         case S3C2410_DMAOP_PAUSE:
1012         case S3C2410_DMAOP_RESUME:
1013                 return -ENOENT;
1014
1015         case S3C2410_DMAOP_FLUSH:
1016                 return s3c2410_dma_flush(chan);
1017
1018         case S3C2410_DMAOP_STARTED:
1019                 return s3c2410_dma_started(chan);
1020
1021         case S3C2410_DMAOP_TIMEOUT:
1022                 return 0;
1023
1024         }
1025
1026         return -ENOENT;      /* unknown, don't bother */
1027 }
1028
1029 EXPORT_SYMBOL(s3c2410_dma_ctrl);
1030
1031 /* DMA configuration for each channel
1032  *
1033  * DISRCC -> source of the DMA (AHB,APB)
1034  * DISRC  -> source address of the DMA
1035  * DIDSTC -> destination of the DMA (AHB,APD)
1036  * DIDST  -> destination address of the DMA
1037 */
1038
1039 /* s3c2410_dma_config
1040  *
1041  * xfersize:     size of unit in bytes (1,2,4)
1042  * dcon:         base value of the DCONx register
1043 */
1044
1045 int s3c2410_dma_config(dmach_t channel,
1046                        int xferunit,
1047                        int dcon)
1048 {
1049         s3c2410_dma_chan_t *chan = &s3c2410_chans[channel];
1050
1051         pr_debug("%s: chan=%d, xfer_unit=%d, dcon=%08x\n",
1052                  __FUNCTION__, channel, xferunit, dcon);
1053
1054         check_channel(channel);
1055
1056         switch (xferunit) {
1057         case 1:
1058                 dcon |= S3C2410_DCON_BYTE;
1059                 break;
1060
1061         case 2:
1062                 dcon |= S3C2410_DCON_HALFWORD;
1063                 break;
1064
1065         case 4:
1066                 dcon |= S3C2410_DCON_WORD;
1067                 break;
1068
1069         default:
1070                 pr_debug("%s: bad transfer size %d\n", __FUNCTION__, xferunit);
1071                 return -EINVAL;
1072         }
1073
1074         dcon |= S3C2410_DCON_HWTRIG;
1075         dcon |= S3C2410_DCON_INTREQ;
1076
1077         pr_debug("%s: dcon now %08x\n", __FUNCTION__, dcon);
1078
1079         chan->dcon = dcon;
1080         chan->xfer_unit = xferunit;
1081
1082         return 0;
1083 }
1084
1085 EXPORT_SYMBOL(s3c2410_dma_config);
1086
1087 int s3c2410_dma_setflags(dmach_t channel, unsigned int flags)
1088 {
1089         s3c2410_dma_chan_t *chan = &s3c2410_chans[channel];
1090
1091         check_channel(channel);
1092
1093         pr_debug("%s: chan=%p, flags=%08x\n", __FUNCTION__, chan, flags);
1094
1095         chan->flags = flags;
1096
1097         return 0;
1098 }
1099
1100 EXPORT_SYMBOL(s3c2410_dma_setflags);
1101
1102
1103 /* do we need to protect the settings of the fields from
1104  * irq?
1105 */
1106
1107 int s3c2410_dma_set_opfn(dmach_t channel, s3c2410_dma_opfn_t rtn)
1108 {
1109         s3c2410_dma_chan_t *chan = &s3c2410_chans[channel];
1110
1111         check_channel(channel);
1112
1113         pr_debug("%s: chan=%p, op rtn=%p\n", __FUNCTION__, chan, rtn);
1114
1115         chan->op_fn = rtn;
1116
1117         return 0;
1118 }
1119
1120 EXPORT_SYMBOL(s3c2410_dma_set_opfn);
1121
1122 int s3c2410_dma_set_buffdone_fn(dmach_t channel, s3c2410_dma_cbfn_t rtn)
1123 {
1124         s3c2410_dma_chan_t *chan = &s3c2410_chans[channel];
1125
1126         check_channel(channel);
1127
1128         pr_debug("%s: chan=%p, callback rtn=%p\n", __FUNCTION__, chan, rtn);
1129
1130         chan->callback_fn = rtn;
1131
1132         return 0;
1133 }
1134
1135 EXPORT_SYMBOL(s3c2410_dma_set_buffdone_fn);
1136
1137 /* s3c2410_dma_devconfig
1138  *
1139  * configure the dma source/destination hardware type and address
1140  *
1141  * source:    S3C2410_DMASRC_HW: source is hardware
1142  *            S3C2410_DMASRC_MEM: source is memory
1143  *
1144  * hwcfg:     the value for xxxSTCn register,
1145  *            bit 0: 0=increment pointer, 1=leave pointer
1146  *            bit 1: 0=soucre is AHB, 1=soucre is APB
1147  *
1148  * devaddr:   physical address of the source
1149 */
1150
1151 int s3c2410_dma_devconfig(int channel,
1152                           s3c2410_dmasrc_t source,
1153                           int hwcfg,
1154                           unsigned long devaddr)
1155 {
1156         s3c2410_dma_chan_t *chan = &s3c2410_chans[channel];
1157
1158         check_channel(channel);
1159
1160         pr_debug("%s: source=%d, hwcfg=%08x, devaddr=%08lx\n",
1161                  __FUNCTION__, (int)source, hwcfg, devaddr);
1162
1163         chan->source = source;
1164         chan->dev_addr = devaddr;
1165
1166         switch (source) {
1167         case S3C2410_DMASRC_HW:
1168                 /* source is hardware */
1169                 pr_debug("%s: hw source, devaddr=%08lx, hwcfg=%d\n",
1170                          __FUNCTION__, devaddr, hwcfg);
1171                 dma_wrreg(chan, S3C2410_DMA_DISRCC, hwcfg & 3);
1172                 dma_wrreg(chan, S3C2410_DMA_DISRC,  devaddr);
1173                 dma_wrreg(chan, S3C2410_DMA_DIDSTC, (0<<1) | (0<<0));
1174
1175                 chan->addr_reg = dma_regaddr(chan, S3C2410_DMA_DIDST);
1176                 return 0;
1177
1178         case S3C2410_DMASRC_MEM:
1179                 /* source is memory */
1180                 pr_debug( "%s: mem source, devaddr=%08lx, hwcfg=%d\n",
1181                           __FUNCTION__, devaddr, hwcfg);
1182                 dma_wrreg(chan, S3C2410_DMA_DISRCC, (0<<1) | (0<<0));
1183                 dma_wrreg(chan, S3C2410_DMA_DIDST,  devaddr);
1184                 dma_wrreg(chan, S3C2410_DMA_DIDSTC, hwcfg & 3);
1185
1186                 chan->addr_reg = dma_regaddr(chan, S3C2410_DMA_DISRC);
1187                 return 0;
1188         }
1189
1190         printk(KERN_ERR "dma%d: invalid source type (%d)\n", channel, source);
1191         return -EINVAL;
1192 }
1193
1194 EXPORT_SYMBOL(s3c2410_dma_devconfig);
1195
1196 /* s3c2410_dma_getposition
1197  *
1198  * returns the current transfer points for the dma source and destination
1199 */
1200
1201 int s3c2410_dma_getposition(dmach_t channel, dma_addr_t *src, dma_addr_t *dst)
1202 {
1203         s3c2410_dma_chan_t *chan = &s3c2410_chans[channel];
1204
1205         check_channel(channel);
1206
1207         if (src != NULL)
1208                 *src = dma_rdreg(chan, S3C2410_DMA_DCSRC);
1209
1210         if (dst != NULL)
1211                 *dst = dma_rdreg(chan, S3C2410_DMA_DCDST);
1212
1213         return 0;
1214 }
1215
1216 EXPORT_SYMBOL(s3c2410_dma_getposition);
1217
1218
1219 /* system device class */
1220
1221 #ifdef CONFIG_PM
1222
1223 static int s3c2410_dma_suspend(struct sys_device *dev, pm_message_t state)
1224 {
1225         s3c2410_dma_chan_t *cp = container_of(dev, s3c2410_dma_chan_t, dev);
1226
1227         printk(KERN_DEBUG "suspending dma channel %d\n", cp->number);
1228
1229         if (dma_rdreg(cp, S3C2410_DMA_DMASKTRIG) & S3C2410_DMASKTRIG_ON) {
1230                 /* the dma channel is still working, which is probably
1231                  * a bad thing to do over suspend/resume. We stop the
1232                  * channel and assume that the client is either going to
1233                  * retry after resume, or that it is broken.
1234                  */
1235
1236                 printk(KERN_INFO "dma: stopping channel %d due to suspend\n",
1237                        cp->number);
1238
1239                 s3c2410_dma_dostop(cp);
1240         }
1241
1242         return 0;
1243 }
1244
1245 static int s3c2410_dma_resume(struct sys_device *dev)
1246 {
1247         return 0;
1248 }
1249
1250 #else
1251 #define s3c2410_dma_suspend NULL
1252 #define s3c2410_dma_resume  NULL
1253 #endif /* CONFIG_PM */
1254
1255 static struct sysdev_class dma_sysclass = {
1256         set_kset_name("s3c24xx-dma"),
1257         .suspend        = s3c2410_dma_suspend,
1258         .resume         = s3c2410_dma_resume,
1259 };
1260
1261 /* kmem cache implementation */
1262
1263 static void s3c2410_dma_cache_ctor(void *p, kmem_cache_t *c, unsigned long f)
1264 {
1265         memset(p, 0, sizeof(s3c2410_dma_buf_t));
1266 }
1267
1268
1269 /* initialisation code */
1270
1271 static int __init s3c2410_init_dma(void)
1272 {
1273         s3c2410_dma_chan_t *cp;
1274         int channel;
1275         int ret;
1276
1277         printk("S3C2410 DMA Driver, (c) 2003-2004 Simtec Electronics\n");
1278
1279         dma_base = ioremap(S3C24XX_PA_DMA, 0x200);
1280         if (dma_base == NULL) {
1281                 printk(KERN_ERR "dma failed to remap register block\n");
1282                 return -ENOMEM;
1283         }
1284
1285         ret = sysdev_class_register(&dma_sysclass);
1286         if (ret != 0) {
1287                 printk(KERN_ERR "dma sysclass registration failed\n");
1288                 goto err;
1289         }
1290
1291         dma_kmem = kmem_cache_create("dma_desc", sizeof(s3c2410_dma_buf_t), 0,
1292                                      SLAB_HWCACHE_ALIGN,
1293                                      s3c2410_dma_cache_ctor, NULL);
1294
1295         if (dma_kmem == NULL) {
1296                 printk(KERN_ERR "dma failed to make kmem cache\n");
1297                 ret = -ENOMEM;
1298                 goto err;
1299         }
1300
1301         for (channel = 0; channel < S3C2410_DMA_CHANNELS; channel++) {
1302                 cp = &s3c2410_chans[channel];
1303
1304                 memset(cp, 0, sizeof(s3c2410_dma_chan_t));
1305
1306                 /* dma channel irqs are in order.. */
1307                 cp->number = channel;
1308                 cp->irq    = channel + IRQ_DMA0;
1309                 cp->regs   = dma_base + (channel*0x40);
1310
1311                 /* point current stats somewhere */
1312                 cp->stats  = &cp->stats_store;
1313                 cp->stats_store.timeout_shortest = LONG_MAX;
1314
1315                 /* basic channel configuration */
1316
1317                 cp->load_timeout = 1<<18;
1318
1319                 /* register system device */
1320
1321                 cp->dev.cls = &dma_sysclass;
1322                 cp->dev.id  = channel;
1323                 ret = sysdev_register(&cp->dev);
1324
1325                 printk("DMA channel %d at %p, irq %d\n",
1326                        cp->number, cp->regs, cp->irq);
1327         }
1328
1329         return 0;
1330
1331  err:
1332         kmem_cache_destroy(dma_kmem);
1333         iounmap(dma_base);
1334         dma_base = NULL;
1335         return ret;
1336 }
1337
1338 __initcall(s3c2410_init_dma);