Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes...
[linux-2.6] / arch / arm / plat-s3c24xx / dma.c
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/io.h>
29
30 #include <asm/system.h>
31 #include <asm/irq.h>
32 #include <mach/hardware.h>
33 #include <mach/dma.h>
34 #include <mach/map.h>
35
36 #include <plat/dma-plat.h>
37 #include <plat/regs-dma.h>
38
39 /* io map for dma */
40 static void __iomem *dma_base;
41 static struct kmem_cache *dma_kmem;
42
43 static int dma_channels;
44
45 static struct s3c24xx_dma_selection dma_sel;
46
47
48 /* debugging functions */
49
50 #define BUF_MAGIC (0xcafebabe)
51
52 #define dmawarn(fmt...) printk(KERN_DEBUG fmt)
53
54 #define dma_regaddr(chan, reg) ((chan)->regs + (reg))
55
56 #if 1
57 #define dma_wrreg(chan, reg, val) writel((val), (chan)->regs + (reg))
58 #else
59 static inline void
60 dma_wrreg(struct s3c2410_dma_chan *chan, int reg, unsigned long val)
61 {
62         pr_debug("writing %08x to register %08x\n",(unsigned int)val,reg);
63         writel(val, dma_regaddr(chan, reg));
64 }
65 #endif
66
67 #define dma_rdreg(chan, reg) readl((chan)->regs + (reg))
68
69 /* captured register state for debug */
70
71 struct s3c2410_dma_regstate {
72         unsigned long         dcsrc;
73         unsigned long         disrc;
74         unsigned long         dstat;
75         unsigned long         dcon;
76         unsigned long         dmsktrig;
77 };
78
79 #ifdef CONFIG_S3C2410_DMA_DEBUG
80
81 /* dmadbg_showregs
82  *
83  * simple debug routine to print the current state of the dma registers
84 */
85
86 static void
87 dmadbg_capture(struct s3c2410_dma_chan *chan, struct s3c2410_dma_regstate *regs)
88 {
89         regs->dcsrc    = dma_rdreg(chan, S3C2410_DMA_DCSRC);
90         regs->disrc    = dma_rdreg(chan, S3C2410_DMA_DISRC);
91         regs->dstat    = dma_rdreg(chan, S3C2410_DMA_DSTAT);
92         regs->dcon     = dma_rdreg(chan, S3C2410_DMA_DCON);
93         regs->dmsktrig = dma_rdreg(chan, S3C2410_DMA_DMASKTRIG);
94 }
95
96 static void
97 dmadbg_dumpregs(const char *fname, int line, struct s3c2410_dma_chan *chan,
98                  struct s3c2410_dma_regstate *regs)
99 {
100         printk(KERN_DEBUG "dma%d: %s:%d: DCSRC=%08lx, DISRC=%08lx, DSTAT=%08lx DMT=%02lx, DCON=%08lx\n",
101                chan->number, fname, line,
102                regs->dcsrc, regs->disrc, regs->dstat, regs->dmsktrig,
103                regs->dcon);
104 }
105
106 static void
107 dmadbg_showchan(const char *fname, int line, struct s3c2410_dma_chan *chan)
108 {
109         struct s3c2410_dma_regstate state;
110
111         dmadbg_capture(chan, &state);
112
113         printk(KERN_DEBUG "dma%d: %s:%d: ls=%d, cur=%p, %p %p\n",
114                chan->number, fname, line, chan->load_state,
115                chan->curr, chan->next, chan->end);
116
117         dmadbg_dumpregs(fname, line, chan, &state);
118 }
119
120 static void
121 dmadbg_showregs(const char *fname, int line, struct s3c2410_dma_chan *chan)
122 {
123         struct s3c2410_dma_regstate state;
124
125         dmadbg_capture(chan, &state);
126         dmadbg_dumpregs(fname, line, chan, &state);
127 }
128
129 #define dbg_showregs(chan) dmadbg_showregs(__func__, __LINE__, (chan))
130 #define dbg_showchan(chan) dmadbg_showchan(__func__, __LINE__, (chan))
131 #else
132 #define dbg_showregs(chan) do { } while(0)
133 #define dbg_showchan(chan) do { } while(0)
134 #endif /* CONFIG_S3C2410_DMA_DEBUG */
135
136 /* s3c2410_dma_stats_timeout
137  *
138  * Update DMA stats from timeout info
139 */
140
141 static void
142 s3c2410_dma_stats_timeout(struct s3c2410_dma_stats *stats, int val)
143 {
144         if (stats == NULL)
145                 return;
146
147         if (val > stats->timeout_longest)
148                 stats->timeout_longest = val;
149         if (val < stats->timeout_shortest)
150                 stats->timeout_shortest = val;
151
152         stats->timeout_avg += val;
153 }
154
155 /* s3c2410_dma_waitforload
156  *
157  * wait for the DMA engine to load a buffer, and update the state accordingly
158 */
159
160 static int
161 s3c2410_dma_waitforload(struct s3c2410_dma_chan *chan, int line)
162 {
163         int timeout = chan->load_timeout;
164         int took;
165
166         if (chan->load_state != S3C2410_DMALOAD_1LOADED) {
167                 printk(KERN_ERR "dma%d: s3c2410_dma_waitforload() called in loadstate %d from line %d\n", chan->number, chan->load_state, line);
168                 return 0;
169         }
170
171         if (chan->stats != NULL)
172                 chan->stats->loads++;
173
174         while (--timeout > 0) {
175                 if ((dma_rdreg(chan, S3C2410_DMA_DSTAT) << (32-20)) != 0) {
176                         took = chan->load_timeout - timeout;
177
178                         s3c2410_dma_stats_timeout(chan->stats, took);
179
180                         switch (chan->load_state) {
181                         case S3C2410_DMALOAD_1LOADED:
182                                 chan->load_state = S3C2410_DMALOAD_1RUNNING;
183                                 break;
184
185                         default:
186                                 printk(KERN_ERR "dma%d: unknown load_state in s3c2410_dma_waitforload() %d\n", chan->number, chan->load_state);
187                         }
188
189                         return 1;
190                 }
191         }
192
193         if (chan->stats != NULL) {
194                 chan->stats->timeout_failed++;
195         }
196
197         return 0;
198 }
199
200 /* s3c2410_dma_loadbuffer
201  *
202  * load a buffer, and update the channel state
203 */
204
205 static inline int
206 s3c2410_dma_loadbuffer(struct s3c2410_dma_chan *chan,
207                        struct s3c2410_dma_buf *buf)
208 {
209         unsigned long reload;
210
211         pr_debug("s3c2410_chan_loadbuffer: loading buff %p (0x%08lx,0x%06x)\n",
212                  buf, (unsigned long)buf->data, buf->size);
213
214         if (buf == NULL) {
215                 dmawarn("buffer is NULL\n");
216                 return -EINVAL;
217         }
218
219         /* check the state of the channel before we do anything */
220
221         if (chan->load_state == S3C2410_DMALOAD_1LOADED) {
222                 dmawarn("load_state is S3C2410_DMALOAD_1LOADED\n");
223         }
224
225         if (chan->load_state == S3C2410_DMALOAD_1LOADED_1RUNNING) {
226                 dmawarn("state is S3C2410_DMALOAD_1LOADED_1RUNNING\n");
227         }
228
229         /* it would seem sensible if we are the last buffer to not bother
230          * with the auto-reload bit, so that the DMA engine will not try
231          * and load another transfer after this one has finished...
232          */
233         if (chan->load_state == S3C2410_DMALOAD_NONE) {
234                 pr_debug("load_state is none, checking for noreload (next=%p)\n",
235                          buf->next);
236                 reload = (buf->next == NULL) ? S3C2410_DCON_NORELOAD : 0;
237         } else {
238                 //pr_debug("load_state is %d => autoreload\n", chan->load_state);
239                 reload = S3C2410_DCON_AUTORELOAD;
240         }
241
242         if ((buf->data & 0xf0000000) != 0x30000000) {
243                 dmawarn("dmaload: buffer is %p\n", (void *)buf->data);
244         }
245
246         writel(buf->data, chan->addr_reg);
247
248         dma_wrreg(chan, S3C2410_DMA_DCON,
249                   chan->dcon | reload | (buf->size/chan->xfer_unit));
250
251         chan->next = buf->next;
252
253         /* update the state of the channel */
254
255         switch (chan->load_state) {
256         case S3C2410_DMALOAD_NONE:
257                 chan->load_state = S3C2410_DMALOAD_1LOADED;
258                 break;
259
260         case S3C2410_DMALOAD_1RUNNING:
261                 chan->load_state = S3C2410_DMALOAD_1LOADED_1RUNNING;
262                 break;
263
264         default:
265                 dmawarn("dmaload: unknown state %d in loadbuffer\n",
266                         chan->load_state);
267                 break;
268         }
269
270         return 0;
271 }
272
273 /* s3c2410_dma_call_op
274  *
275  * small routine to call the op routine with the given op if it has been
276  * registered
277 */
278
279 static void
280 s3c2410_dma_call_op(struct s3c2410_dma_chan *chan, enum s3c2410_chan_op op)
281 {
282         if (chan->op_fn != NULL) {
283                 (chan->op_fn)(chan, op);
284         }
285 }
286
287 /* s3c2410_dma_buffdone
288  *
289  * small wrapper to check if callback routine needs to be called, and
290  * if so, call it
291 */
292
293 static inline void
294 s3c2410_dma_buffdone(struct s3c2410_dma_chan *chan, struct s3c2410_dma_buf *buf,
295                      enum s3c2410_dma_buffresult result)
296 {
297 #if 0
298         pr_debug("callback_fn=%p, buf=%p, id=%p, size=%d, result=%d\n",
299                  chan->callback_fn, buf, buf->id, buf->size, result);
300 #endif
301
302         if (chan->callback_fn != NULL) {
303                 (chan->callback_fn)(chan, buf->id, buf->size, result);
304         }
305 }
306
307 /* s3c2410_dma_start
308  *
309  * start a dma channel going
310 */
311
312 static int s3c2410_dma_start(struct s3c2410_dma_chan *chan)
313 {
314         unsigned long tmp;
315         unsigned long flags;
316
317         pr_debug("s3c2410_start_dma: channel=%d\n", chan->number);
318
319         local_irq_save(flags);
320
321         if (chan->state == S3C2410_DMA_RUNNING) {
322                 pr_debug("s3c2410_start_dma: already running (%d)\n", chan->state);
323                 local_irq_restore(flags);
324                 return 0;
325         }
326
327         chan->state = S3C2410_DMA_RUNNING;
328
329         /* check wether there is anything to load, and if not, see
330          * if we can find anything to load
331          */
332
333         if (chan->load_state == S3C2410_DMALOAD_NONE) {
334                 if (chan->next == NULL) {
335                         printk(KERN_ERR "dma%d: channel has nothing loaded\n",
336                                chan->number);
337                         chan->state = S3C2410_DMA_IDLE;
338                         local_irq_restore(flags);
339                         return -EINVAL;
340                 }
341
342                 s3c2410_dma_loadbuffer(chan, chan->next);
343         }
344
345         dbg_showchan(chan);
346
347         /* enable the channel */
348
349         if (!chan->irq_enabled) {
350                 enable_irq(chan->irq);
351                 chan->irq_enabled = 1;
352         }
353
354         /* start the channel going */
355
356         tmp = dma_rdreg(chan, S3C2410_DMA_DMASKTRIG);
357         tmp &= ~S3C2410_DMASKTRIG_STOP;
358         tmp |= S3C2410_DMASKTRIG_ON;
359         dma_wrreg(chan, S3C2410_DMA_DMASKTRIG, tmp);
360
361         pr_debug("dma%d: %08lx to DMASKTRIG\n", chan->number, tmp);
362
363 #if 0
364         /* the dma buffer loads should take care of clearing the AUTO
365          * reloading feature */
366         tmp = dma_rdreg(chan, S3C2410_DMA_DCON);
367         tmp &= ~S3C2410_DCON_NORELOAD;
368         dma_wrreg(chan, S3C2410_DMA_DCON, tmp);
369 #endif
370
371         s3c2410_dma_call_op(chan, S3C2410_DMAOP_START);
372
373         dbg_showchan(chan);
374
375         /* if we've only loaded one buffer onto the channel, then chec
376          * to see if we have another, and if so, try and load it so when
377          * the first buffer is finished, the new one will be loaded onto
378          * the channel */
379
380         if (chan->next != NULL) {
381                 if (chan->load_state == S3C2410_DMALOAD_1LOADED) {
382
383                         if (s3c2410_dma_waitforload(chan, __LINE__) == 0) {
384                                 pr_debug("%s: buff not yet loaded, no more todo\n",
385                                          __func__);
386                         } else {
387                                 chan->load_state = S3C2410_DMALOAD_1RUNNING;
388                                 s3c2410_dma_loadbuffer(chan, chan->next);
389                         }
390
391                 } else if (chan->load_state == S3C2410_DMALOAD_1RUNNING) {
392                         s3c2410_dma_loadbuffer(chan, chan->next);
393                 }
394         }
395
396
397         local_irq_restore(flags);
398
399         return 0;
400 }
401
402 /* s3c2410_dma_canload
403  *
404  * work out if we can queue another buffer into the DMA engine
405 */
406
407 static int
408 s3c2410_dma_canload(struct s3c2410_dma_chan *chan)
409 {
410         if (chan->load_state == S3C2410_DMALOAD_NONE ||
411             chan->load_state == S3C2410_DMALOAD_1RUNNING)
412                 return 1;
413
414         return 0;
415 }
416
417 /* s3c2410_dma_enqueue
418  *
419  * queue an given buffer for dma transfer.
420  *
421  * id         the device driver's id information for this buffer
422  * data       the physical address of the buffer data
423  * size       the size of the buffer in bytes
424  *
425  * If the channel is not running, then the flag S3C2410_DMAF_AUTOSTART
426  * is checked, and if set, the channel is started. If this flag isn't set,
427  * then an error will be returned.
428  *
429  * It is possible to queue more than one DMA buffer onto a channel at
430  * once, and the code will deal with the re-loading of the next buffer
431  * when necessary.
432 */
433
434 int s3c2410_dma_enqueue(unsigned int channel, void *id,
435                         dma_addr_t data, int size)
436 {
437         struct s3c2410_dma_chan *chan = s3c_dma_lookup_channel(channel);
438         struct s3c2410_dma_buf *buf;
439         unsigned long flags;
440
441         if (chan == NULL)
442                 return -EINVAL;
443
444         pr_debug("%s: id=%p, data=%08x, size=%d\n",
445                  __func__, id, (unsigned int)data, size);
446
447         buf = kmem_cache_alloc(dma_kmem, GFP_ATOMIC);
448         if (buf == NULL) {
449                 pr_debug("%s: out of memory (%ld alloc)\n",
450                          __func__, (long)sizeof(*buf));
451                 return -ENOMEM;
452         }
453
454         //pr_debug("%s: new buffer %p\n", __func__, buf);
455         //dbg_showchan(chan);
456
457         buf->next  = NULL;
458         buf->data  = buf->ptr = data;
459         buf->size  = size;
460         buf->id    = id;
461         buf->magic = BUF_MAGIC;
462
463         local_irq_save(flags);
464
465         if (chan->curr == NULL) {
466                 /* we've got nothing loaded... */
467                 pr_debug("%s: buffer %p queued onto empty channel\n",
468                          __func__, buf);
469
470                 chan->curr = buf;
471                 chan->end  = buf;
472                 chan->next = NULL;
473         } else {
474                 pr_debug("dma%d: %s: buffer %p queued onto non-empty channel\n",
475                          chan->number, __func__, buf);
476
477                 if (chan->end == NULL)
478                         pr_debug("dma%d: %s: %p not empty, and chan->end==NULL?\n",
479                                  chan->number, __func__, chan);
480
481                 chan->end->next = buf;
482                 chan->end = buf;
483         }
484
485         /* if necessary, update the next buffer field */
486         if (chan->next == NULL)
487                 chan->next = buf;
488
489         /* check to see if we can load a buffer */
490         if (chan->state == S3C2410_DMA_RUNNING) {
491                 if (chan->load_state == S3C2410_DMALOAD_1LOADED && 1) {
492                         if (s3c2410_dma_waitforload(chan, __LINE__) == 0) {
493                                 printk(KERN_ERR "dma%d: loadbuffer:"
494                                        "timeout loading buffer\n",
495                                        chan->number);
496                                 dbg_showchan(chan);
497                                 local_irq_restore(flags);
498                                 return -EINVAL;
499                         }
500                 }
501
502                 while (s3c2410_dma_canload(chan) && chan->next != NULL) {
503                         s3c2410_dma_loadbuffer(chan, chan->next);
504                 }
505         } else if (chan->state == S3C2410_DMA_IDLE) {
506                 if (chan->flags & S3C2410_DMAF_AUTOSTART) {
507                         s3c2410_dma_ctrl(chan->number | DMACH_LOW_LEVEL,
508                                          S3C2410_DMAOP_START);
509                 }
510         }
511
512         local_irq_restore(flags);
513         return 0;
514 }
515
516 EXPORT_SYMBOL(s3c2410_dma_enqueue);
517
518 static inline void
519 s3c2410_dma_freebuf(struct s3c2410_dma_buf *buf)
520 {
521         int magicok = (buf->magic == BUF_MAGIC);
522
523         buf->magic = -1;
524
525         if (magicok) {
526                 kmem_cache_free(dma_kmem, buf);
527         } else {
528                 printk("s3c2410_dma_freebuf: buff %p with bad magic\n", buf);
529         }
530 }
531
532 /* s3c2410_dma_lastxfer
533  *
534  * called when the system is out of buffers, to ensure that the channel
535  * is prepared for shutdown.
536 */
537
538 static inline void
539 s3c2410_dma_lastxfer(struct s3c2410_dma_chan *chan)
540 {
541 #if 0
542         pr_debug("dma%d: s3c2410_dma_lastxfer: load_state %d\n",
543                  chan->number, chan->load_state);
544 #endif
545
546         switch (chan->load_state) {
547         case S3C2410_DMALOAD_NONE:
548                 break;
549
550         case S3C2410_DMALOAD_1LOADED:
551                 if (s3c2410_dma_waitforload(chan, __LINE__) == 0) {
552                                 /* flag error? */
553                         printk(KERN_ERR "dma%d: timeout waiting for load (%s)\n",
554                                chan->number, __func__);
555                         return;
556                 }
557                 break;
558
559         case S3C2410_DMALOAD_1LOADED_1RUNNING:
560                 /* I belive in this case we do not have anything to do
561                  * until the next buffer comes along, and we turn off the
562                  * reload */
563                 return;
564
565         default:
566                 pr_debug("dma%d: lastxfer: unhandled load_state %d with no next\n",
567                          chan->number, chan->load_state);
568                 return;
569
570         }
571
572         /* hopefully this'll shut the damned thing up after the transfer... */
573         dma_wrreg(chan, S3C2410_DMA_DCON, chan->dcon | S3C2410_DCON_NORELOAD);
574 }
575
576
577 #define dmadbg2(x...)
578
579 static irqreturn_t
580 s3c2410_dma_irq(int irq, void *devpw)
581 {
582         struct s3c2410_dma_chan *chan = (struct s3c2410_dma_chan *)devpw;
583         struct s3c2410_dma_buf  *buf;
584
585         buf = chan->curr;
586
587         dbg_showchan(chan);
588
589         /* modify the channel state */
590
591         switch (chan->load_state) {
592         case S3C2410_DMALOAD_1RUNNING:
593                 /* TODO - if we are running only one buffer, we probably
594                  * want to reload here, and then worry about the buffer
595                  * callback */
596
597                 chan->load_state = S3C2410_DMALOAD_NONE;
598                 break;
599
600         case S3C2410_DMALOAD_1LOADED:
601                 /* iirc, we should go back to NONE loaded here, we
602                  * had a buffer, and it was never verified as being
603                  * loaded.
604                  */
605
606                 chan->load_state = S3C2410_DMALOAD_NONE;
607                 break;
608
609         case S3C2410_DMALOAD_1LOADED_1RUNNING:
610                 /* we'll worry about checking to see if another buffer is
611                  * ready after we've called back the owner. This should
612                  * ensure we do not wait around too long for the DMA
613                  * engine to start the next transfer
614                  */
615
616                 chan->load_state = S3C2410_DMALOAD_1LOADED;
617                 break;
618
619         case S3C2410_DMALOAD_NONE:
620                 printk(KERN_ERR "dma%d: IRQ with no loaded buffer?\n",
621                        chan->number);
622                 break;
623
624         default:
625                 printk(KERN_ERR "dma%d: IRQ in invalid load_state %d\n",
626                        chan->number, chan->load_state);
627                 break;
628         }
629
630         if (buf != NULL) {
631                 /* update the chain to make sure that if we load any more
632                  * buffers when we call the callback function, things should
633                  * work properly */
634
635                 chan->curr = buf->next;
636                 buf->next  = NULL;
637
638                 if (buf->magic != BUF_MAGIC) {
639                         printk(KERN_ERR "dma%d: %s: buf %p incorrect magic\n",
640                                chan->number, __func__, buf);
641                         return IRQ_HANDLED;
642                 }
643
644                 s3c2410_dma_buffdone(chan, buf, S3C2410_RES_OK);
645
646                 /* free resouces */
647                 s3c2410_dma_freebuf(buf);
648         } else {
649         }
650
651         /* only reload if the channel is still running... our buffer done
652          * routine may have altered the state by requesting the dma channel
653          * to stop or shutdown... */
654
655         /* todo: check that when the channel is shut-down from inside this
656          * function, we cope with unsetting reload, etc */
657
658         if (chan->next != NULL && chan->state != S3C2410_DMA_IDLE) {
659                 unsigned long flags;
660
661                 switch (chan->load_state) {
662                 case S3C2410_DMALOAD_1RUNNING:
663                         /* don't need to do anything for this state */
664                         break;
665
666                 case S3C2410_DMALOAD_NONE:
667                         /* can load buffer immediately */
668                         break;
669
670                 case S3C2410_DMALOAD_1LOADED:
671                         if (s3c2410_dma_waitforload(chan, __LINE__) == 0) {
672                                 /* flag error? */
673                                 printk(KERN_ERR "dma%d: timeout waiting for load (%s)\n",
674                                        chan->number, __func__);
675                                 return IRQ_HANDLED;
676                         }
677
678                         break;
679
680                 case S3C2410_DMALOAD_1LOADED_1RUNNING:
681                         goto no_load;
682
683                 default:
684                         printk(KERN_ERR "dma%d: unknown load_state in irq, %d\n",
685                                chan->number, chan->load_state);
686                         return IRQ_HANDLED;
687                 }
688
689                 local_irq_save(flags);
690                 s3c2410_dma_loadbuffer(chan, chan->next);
691                 local_irq_restore(flags);
692         } else {
693                 s3c2410_dma_lastxfer(chan);
694
695                 /* see if we can stop this channel.. */
696                 if (chan->load_state == S3C2410_DMALOAD_NONE) {
697                         pr_debug("dma%d: end of transfer, stopping channel (%ld)\n",
698                                  chan->number, jiffies);
699                         s3c2410_dma_ctrl(chan->number | DMACH_LOW_LEVEL,
700                                          S3C2410_DMAOP_STOP);
701                 }
702         }
703
704  no_load:
705         return IRQ_HANDLED;
706 }
707
708 static struct s3c2410_dma_chan *s3c2410_dma_map_channel(int channel);
709
710 /* s3c2410_request_dma
711  *
712  * get control of an dma channel
713 */
714
715 int s3c2410_dma_request(unsigned int channel,
716                         struct s3c2410_dma_client *client,
717                         void *dev)
718 {
719         struct s3c2410_dma_chan *chan;
720         unsigned long flags;
721         int err;
722
723         pr_debug("dma%d: s3c2410_request_dma: client=%s, dev=%p\n",
724                  channel, client->name, dev);
725
726         local_irq_save(flags);
727
728         chan = s3c2410_dma_map_channel(channel);
729         if (chan == NULL) {
730                 local_irq_restore(flags);
731                 return -EBUSY;
732         }
733
734         dbg_showchan(chan);
735
736         chan->client = client;
737         chan->in_use = 1;
738
739         if (!chan->irq_claimed) {
740                 pr_debug("dma%d: %s : requesting irq %d\n",
741                          channel, __func__, chan->irq);
742
743                 chan->irq_claimed = 1;
744                 local_irq_restore(flags);
745
746                 err = request_irq(chan->irq, s3c2410_dma_irq, IRQF_DISABLED,
747                                   client->name, (void *)chan);
748
749                 local_irq_save(flags);
750
751                 if (err) {
752                         chan->in_use = 0;
753                         chan->irq_claimed = 0;
754                         local_irq_restore(flags);
755
756                         printk(KERN_ERR "%s: cannot get IRQ %d for DMA %d\n",
757                                client->name, chan->irq, chan->number);
758                         return err;
759                 }
760
761                 chan->irq_enabled = 1;
762         }
763
764         local_irq_restore(flags);
765
766         /* need to setup */
767
768         pr_debug("%s: channel initialised, %p\n", __func__, chan);
769
770         return chan->number | DMACH_LOW_LEVEL;
771 }
772
773 EXPORT_SYMBOL(s3c2410_dma_request);
774
775 /* s3c2410_dma_free
776  *
777  * release the given channel back to the system, will stop and flush
778  * any outstanding transfers, and ensure the channel is ready for the
779  * next claimant.
780  *
781  * Note, although a warning is currently printed if the freeing client
782  * info is not the same as the registrant's client info, the free is still
783  * allowed to go through.
784 */
785
786 int s3c2410_dma_free(unsigned int channel, struct s3c2410_dma_client *client)
787 {
788         struct s3c2410_dma_chan *chan = s3c_dma_lookup_channel(channel);
789         unsigned long flags;
790
791         if (chan == NULL)
792                 return -EINVAL;
793
794         local_irq_save(flags);
795
796         if (chan->client != client) {
797                 printk(KERN_WARNING "dma%d: possible free from different client (channel %p, passed %p)\n",
798                        channel, chan->client, client);
799         }
800
801         /* sort out stopping and freeing the channel */
802
803         if (chan->state != S3C2410_DMA_IDLE) {
804                 pr_debug("%s: need to stop dma channel %p\n",
805                        __func__, chan);
806
807                 /* possibly flush the channel */
808                 s3c2410_dma_ctrl(channel, S3C2410_DMAOP_STOP);
809         }
810
811         chan->client = NULL;
812         chan->in_use = 0;
813
814         if (chan->irq_claimed)
815                 free_irq(chan->irq, (void *)chan);
816
817         chan->irq_claimed = 0;
818
819         if (!(channel & DMACH_LOW_LEVEL))
820                 s3c_dma_chan_map[channel] = NULL;
821
822         local_irq_restore(flags);
823
824         return 0;
825 }
826
827 EXPORT_SYMBOL(s3c2410_dma_free);
828
829 static int s3c2410_dma_dostop(struct s3c2410_dma_chan *chan)
830 {
831         unsigned long flags;
832         unsigned long tmp;
833
834         pr_debug("%s:\n", __func__);
835
836         dbg_showchan(chan);
837
838         local_irq_save(flags);
839
840         s3c2410_dma_call_op(chan,  S3C2410_DMAOP_STOP);
841
842         tmp = dma_rdreg(chan, S3C2410_DMA_DMASKTRIG);
843         tmp |= S3C2410_DMASKTRIG_STOP;
844         //tmp &= ~S3C2410_DMASKTRIG_ON;
845         dma_wrreg(chan, S3C2410_DMA_DMASKTRIG, tmp);
846
847 #if 0
848         /* should also clear interrupts, according to WinCE BSP */
849         tmp = dma_rdreg(chan, S3C2410_DMA_DCON);
850         tmp |= S3C2410_DCON_NORELOAD;
851         dma_wrreg(chan, S3C2410_DMA_DCON, tmp);
852 #endif
853
854         /* should stop do this, or should we wait for flush? */
855         chan->state      = S3C2410_DMA_IDLE;
856         chan->load_state = S3C2410_DMALOAD_NONE;
857
858         local_irq_restore(flags);
859
860         return 0;
861 }
862
863 static void s3c2410_dma_waitforstop(struct s3c2410_dma_chan *chan)
864 {
865         unsigned long tmp;
866         unsigned int timeout = 0x10000;
867
868         while (timeout-- > 0) {
869                 tmp = dma_rdreg(chan, S3C2410_DMA_DMASKTRIG);
870
871                 if (!(tmp & S3C2410_DMASKTRIG_ON))
872                         return;
873         }
874
875         pr_debug("dma%d: failed to stop?\n", chan->number);
876 }
877
878
879 /* s3c2410_dma_flush
880  *
881  * stop the channel, and remove all current and pending transfers
882 */
883
884 static int s3c2410_dma_flush(struct s3c2410_dma_chan *chan)
885 {
886         struct s3c2410_dma_buf *buf, *next;
887         unsigned long flags;
888
889         pr_debug("%s: chan %p (%d)\n", __func__, chan, chan->number);
890
891         dbg_showchan(chan);
892
893         local_irq_save(flags);
894
895         if (chan->state != S3C2410_DMA_IDLE) {
896                 pr_debug("%s: stopping channel...\n", __func__ );
897                 s3c2410_dma_ctrl(chan->number, S3C2410_DMAOP_STOP);
898         }
899
900         buf = chan->curr;
901         if (buf == NULL)
902                 buf = chan->next;
903
904         chan->curr = chan->next = chan->end = NULL;
905
906         if (buf != NULL) {
907                 for ( ; buf != NULL; buf = next) {
908                         next = buf->next;
909
910                         pr_debug("%s: free buffer %p, next %p\n",
911                                __func__, buf, buf->next);
912
913                         s3c2410_dma_buffdone(chan, buf, S3C2410_RES_ABORT);
914                         s3c2410_dma_freebuf(buf);
915                 }
916         }
917
918         dbg_showregs(chan);
919
920         s3c2410_dma_waitforstop(chan);
921
922 #if 0
923         /* should also clear interrupts, according to WinCE BSP */
924         {
925                 unsigned long tmp;
926
927                 tmp = dma_rdreg(chan, S3C2410_DMA_DCON);
928                 tmp |= S3C2410_DCON_NORELOAD;
929                 dma_wrreg(chan, S3C2410_DMA_DCON, tmp);
930         }
931 #endif
932
933         dbg_showregs(chan);
934
935         local_irq_restore(flags);
936
937         return 0;
938 }
939
940 static int s3c2410_dma_started(struct s3c2410_dma_chan *chan)
941 {
942         unsigned long flags;
943
944         local_irq_save(flags);
945
946         dbg_showchan(chan);
947
948         /* if we've only loaded one buffer onto the channel, then chec
949          * to see if we have another, and if so, try and load it so when
950          * the first buffer is finished, the new one will be loaded onto
951          * the channel */
952
953         if (chan->next != NULL) {
954                 if (chan->load_state == S3C2410_DMALOAD_1LOADED) {
955
956                         if (s3c2410_dma_waitforload(chan, __LINE__) == 0) {
957                                 pr_debug("%s: buff not yet loaded, no more todo\n",
958                                          __func__);
959                         } else {
960                                 chan->load_state = S3C2410_DMALOAD_1RUNNING;
961                                 s3c2410_dma_loadbuffer(chan, chan->next);
962                         }
963
964                 } else if (chan->load_state == S3C2410_DMALOAD_1RUNNING) {
965                         s3c2410_dma_loadbuffer(chan, chan->next);
966                 }
967         }
968
969
970         local_irq_restore(flags);
971
972         return 0;
973
974 }
975
976 int
977 s3c2410_dma_ctrl(unsigned int channel, enum s3c2410_chan_op op)
978 {
979         struct s3c2410_dma_chan *chan = s3c_dma_lookup_channel(channel);
980
981         if (chan == NULL)
982                 return -EINVAL;
983
984         switch (op) {
985         case S3C2410_DMAOP_START:
986                 return s3c2410_dma_start(chan);
987
988         case S3C2410_DMAOP_STOP:
989                 return s3c2410_dma_dostop(chan);
990
991         case S3C2410_DMAOP_PAUSE:
992         case S3C2410_DMAOP_RESUME:
993                 return -ENOENT;
994
995         case S3C2410_DMAOP_FLUSH:
996                 return s3c2410_dma_flush(chan);
997
998         case S3C2410_DMAOP_STARTED:
999                 return s3c2410_dma_started(chan);
1000
1001         case S3C2410_DMAOP_TIMEOUT:
1002                 return 0;
1003
1004         }
1005
1006         return -ENOENT;      /* unknown, don't bother */
1007 }
1008
1009 EXPORT_SYMBOL(s3c2410_dma_ctrl);
1010
1011 /* DMA configuration for each channel
1012  *
1013  * DISRCC -> source of the DMA (AHB,APB)
1014  * DISRC  -> source address of the DMA
1015  * DIDSTC -> destination of the DMA (AHB,APD)
1016  * DIDST  -> destination address of the DMA
1017 */
1018
1019 /* s3c2410_dma_config
1020  *
1021  * xfersize:     size of unit in bytes (1,2,4)
1022 */
1023
1024 int s3c2410_dma_config(unsigned int channel,
1025                        int xferunit)
1026 {
1027         struct s3c2410_dma_chan *chan = s3c_dma_lookup_channel(channel);
1028         unsigned int dcon;
1029
1030         pr_debug("%s: chan=%d, xfer_unit=%d, dcon=%08x\n",
1031                  __func__, channel, xferunit, dcon);
1032
1033         if (chan == NULL)
1034                 return -EINVAL;
1035
1036         pr_debug("%s: Initial dcon is %08x\n", __func__, dcon);
1037
1038         dcon = chan->dcon & dma_sel.dcon_mask;
1039
1040         pr_debug("%s: New dcon is %08x\n", __func__, dcon);
1041
1042         switch (chan->req_ch) {
1043         case DMACH_I2S_IN:
1044         case DMACH_I2S_OUT:
1045         case DMACH_PCM_IN:
1046         case DMACH_PCM_OUT:
1047         case DMACH_MIC_IN:
1048         default:
1049                 dcon |= S3C2410_DCON_HANDSHAKE;
1050                 dcon |= S3C2410_DCON_SYNC_PCLK;
1051                 break;
1052
1053         case DMACH_SDI:
1054                 /* note, ensure if need HANDSHAKE or not */
1055                 dcon |= S3C2410_DCON_SYNC_PCLK;
1056                 break;
1057
1058         case DMACH_XD0:
1059         case DMACH_XD1:
1060                 dcon |= S3C2410_DCON_HANDSHAKE;
1061                 dcon |= S3C2410_DCON_SYNC_HCLK;
1062                 break;
1063         }
1064
1065         switch (xferunit) {
1066         case 1:
1067                 dcon |= S3C2410_DCON_BYTE;
1068                 break;
1069
1070         case 2:
1071                 dcon |= S3C2410_DCON_HALFWORD;
1072                 break;
1073
1074         case 4:
1075                 dcon |= S3C2410_DCON_WORD;
1076                 break;
1077
1078         default:
1079                 pr_debug("%s: bad transfer size %d\n", __func__, xferunit);
1080                 return -EINVAL;
1081         }
1082
1083         dcon |= S3C2410_DCON_HWTRIG;
1084         dcon |= S3C2410_DCON_INTREQ;
1085
1086         pr_debug("%s: dcon now %08x\n", __func__, dcon);
1087
1088         chan->dcon = dcon;
1089         chan->xfer_unit = xferunit;
1090
1091         return 0;
1092 }
1093
1094 EXPORT_SYMBOL(s3c2410_dma_config);
1095
1096
1097 /* s3c2410_dma_devconfig
1098  *
1099  * configure the dma source/destination hardware type and address
1100  *
1101  * source:    S3C2410_DMASRC_HW: source is hardware
1102  *            S3C2410_DMASRC_MEM: source is memory
1103  *
1104  * devaddr:   physical address of the source
1105 */
1106
1107 int s3c2410_dma_devconfig(int channel,
1108                           enum s3c2410_dmasrc source,
1109                           unsigned long devaddr)
1110 {
1111         struct s3c2410_dma_chan *chan = s3c_dma_lookup_channel(channel);
1112         unsigned int hwcfg;
1113
1114         if (chan == NULL)
1115                 return -EINVAL;
1116
1117         pr_debug("%s: source=%d, devaddr=%08lx\n",
1118                  __func__, (int)source, devaddr);
1119
1120         chan->source = source;
1121         chan->dev_addr = devaddr;
1122
1123         switch (chan->req_ch) {
1124         case DMACH_XD0:
1125         case DMACH_XD1:
1126                 hwcfg = 0; /* AHB */
1127                 break;
1128
1129         default:
1130                 hwcfg = S3C2410_DISRCC_APB;
1131         }
1132
1133         /* always assume our peripheral desintation is a fixed
1134          * address in memory. */
1135          hwcfg |= S3C2410_DISRCC_INC;
1136
1137         switch (source) {
1138         case S3C2410_DMASRC_HW:
1139                 /* source is hardware */
1140                 pr_debug("%s: hw source, devaddr=%08lx, hwcfg=%d\n",
1141                          __func__, devaddr, hwcfg);
1142                 dma_wrreg(chan, S3C2410_DMA_DISRCC, hwcfg & 3);
1143                 dma_wrreg(chan, S3C2410_DMA_DISRC,  devaddr);
1144                 dma_wrreg(chan, S3C2410_DMA_DIDSTC, (0<<1) | (0<<0));
1145
1146                 chan->addr_reg = dma_regaddr(chan, S3C2410_DMA_DIDST);
1147                 break;
1148
1149         case S3C2410_DMASRC_MEM:
1150                 /* source is memory */
1151                 pr_debug("%s: mem source, devaddr=%08lx, hwcfg=%d\n",
1152                          __func__, devaddr, hwcfg);
1153                 dma_wrreg(chan, S3C2410_DMA_DISRCC, (0<<1) | (0<<0));
1154                 dma_wrreg(chan, S3C2410_DMA_DIDST,  devaddr);
1155                 dma_wrreg(chan, S3C2410_DMA_DIDSTC, hwcfg & 3);
1156
1157                 chan->addr_reg = dma_regaddr(chan, S3C2410_DMA_DISRC);
1158                 break;
1159
1160         default:
1161                 printk(KERN_ERR "dma%d: invalid source type (%d)\n",
1162                        channel, source);
1163
1164                 return -EINVAL;
1165         }
1166
1167         if (dma_sel.direction != NULL)
1168                 (dma_sel.direction)(chan, chan->map, source);
1169
1170         return 0;
1171 }
1172
1173 EXPORT_SYMBOL(s3c2410_dma_devconfig);
1174
1175 /* s3c2410_dma_getposition
1176  *
1177  * returns the current transfer points for the dma source and destination
1178 */
1179
1180 int s3c2410_dma_getposition(unsigned int channel, dma_addr_t *src, dma_addr_t *dst)
1181 {
1182         struct s3c2410_dma_chan *chan = s3c_dma_lookup_channel(channel);
1183
1184         if (chan == NULL)
1185                 return -EINVAL;
1186
1187         if (src != NULL)
1188                 *src = dma_rdreg(chan, S3C2410_DMA_DCSRC);
1189
1190         if (dst != NULL)
1191                 *dst = dma_rdreg(chan, S3C2410_DMA_DCDST);
1192
1193         return 0;
1194 }
1195
1196 EXPORT_SYMBOL(s3c2410_dma_getposition);
1197
1198 static inline struct s3c2410_dma_chan *to_dma_chan(struct sys_device *dev)
1199 {
1200         return container_of(dev, struct s3c2410_dma_chan, dev);
1201 }
1202
1203 /* system device class */
1204
1205 #ifdef CONFIG_PM
1206
1207 static int s3c2410_dma_suspend(struct sys_device *dev, pm_message_t state)
1208 {
1209         struct s3c2410_dma_chan *cp = to_dma_chan(dev);
1210
1211         printk(KERN_DEBUG "suspending dma channel %d\n", cp->number);
1212
1213         if (dma_rdreg(cp, S3C2410_DMA_DMASKTRIG) & S3C2410_DMASKTRIG_ON) {
1214                 /* the dma channel is still working, which is probably
1215                  * a bad thing to do over suspend/resume. We stop the
1216                  * channel and assume that the client is either going to
1217                  * retry after resume, or that it is broken.
1218                  */
1219
1220                 printk(KERN_INFO "dma: stopping channel %d due to suspend\n",
1221                        cp->number);
1222
1223                 s3c2410_dma_dostop(cp);
1224         }
1225
1226         return 0;
1227 }
1228
1229 static int s3c2410_dma_resume(struct sys_device *dev)
1230 {
1231         struct s3c2410_dma_chan *cp = to_dma_chan(dev);
1232         unsigned int no = cp->number | DMACH_LOW_LEVEL;
1233
1234         /* restore channel's hardware configuration */
1235
1236         if (!cp->in_use)
1237                 return 0;
1238
1239         printk(KERN_INFO "dma%d: restoring configuration\n", cp->number);
1240
1241         s3c2410_dma_config(no, cp->xfer_unit);
1242         s3c2410_dma_devconfig(no, cp->source, cp->dev_addr);
1243
1244         /* re-select the dma source for this channel */
1245
1246         if (cp->map != NULL)
1247                 dma_sel.select(cp, cp->map);
1248
1249         return 0;
1250 }
1251
1252 #else
1253 #define s3c2410_dma_suspend NULL
1254 #define s3c2410_dma_resume  NULL
1255 #endif /* CONFIG_PM */
1256
1257 struct sysdev_class dma_sysclass = {
1258         .name           = "s3c24xx-dma",
1259         .suspend        = s3c2410_dma_suspend,
1260         .resume         = s3c2410_dma_resume,
1261 };
1262
1263 /* kmem cache implementation */
1264
1265 static void s3c2410_dma_cache_ctor(void *p)
1266 {
1267         memset(p, 0, sizeof(struct s3c2410_dma_buf));
1268 }
1269
1270 /* initialisation code */
1271
1272 static int __init s3c24xx_dma_sysclass_init(void)
1273 {
1274         int ret = sysdev_class_register(&dma_sysclass);
1275
1276         if (ret != 0)
1277                 printk(KERN_ERR "dma sysclass registration failed\n");
1278
1279         return ret;
1280 }
1281
1282 core_initcall(s3c24xx_dma_sysclass_init);
1283
1284 static int __init s3c24xx_dma_sysdev_register(void)
1285 {
1286         struct s3c2410_dma_chan *cp = s3c2410_chans;
1287         int channel, ret;
1288
1289         for (channel = 0; channel < dma_channels; cp++, channel++) {
1290                 cp->dev.cls = &dma_sysclass;
1291                 cp->dev.id  = channel;
1292                 ret = sysdev_register(&cp->dev);
1293
1294                 if (ret) {
1295                         printk(KERN_ERR "error registering dev for dma %d\n",
1296                                channel);
1297                         return ret;
1298                 }
1299         }
1300
1301         return 0;
1302 }
1303
1304 late_initcall(s3c24xx_dma_sysdev_register);
1305
1306 int __init s3c24xx_dma_init(unsigned int channels, unsigned int irq,
1307                             unsigned int stride)
1308 {
1309         struct s3c2410_dma_chan *cp;
1310         int channel;
1311         int ret;
1312
1313         printk("S3C24XX DMA Driver, (c) 2003-2004,2006 Simtec Electronics\n");
1314
1315         dma_channels = channels;
1316
1317         dma_base = ioremap(S3C24XX_PA_DMA, stride * channels);
1318         if (dma_base == NULL) {
1319                 printk(KERN_ERR "dma failed to remap register block\n");
1320                 return -ENOMEM;
1321         }
1322
1323         dma_kmem = kmem_cache_create("dma_desc",
1324                                      sizeof(struct s3c2410_dma_buf), 0,
1325                                      SLAB_HWCACHE_ALIGN,
1326                                      s3c2410_dma_cache_ctor);
1327
1328         if (dma_kmem == NULL) {
1329                 printk(KERN_ERR "dma failed to make kmem cache\n");
1330                 ret = -ENOMEM;
1331                 goto err;
1332         }
1333
1334         for (channel = 0; channel < channels;  channel++) {
1335                 cp = &s3c2410_chans[channel];
1336
1337                 memset(cp, 0, sizeof(struct s3c2410_dma_chan));
1338
1339                 /* dma channel irqs are in order.. */
1340                 cp->number = channel;
1341                 cp->irq    = channel + irq;
1342                 cp->regs   = dma_base + (channel * stride);
1343
1344                 /* point current stats somewhere */
1345                 cp->stats  = &cp->stats_store;
1346                 cp->stats_store.timeout_shortest = LONG_MAX;
1347
1348                 /* basic channel configuration */
1349
1350                 cp->load_timeout = 1<<18;
1351
1352                 printk("DMA channel %d at %p, irq %d\n",
1353                        cp->number, cp->regs, cp->irq);
1354         }
1355
1356         return 0;
1357
1358  err:
1359         kmem_cache_destroy(dma_kmem);
1360         iounmap(dma_base);
1361         dma_base = NULL;
1362         return ret;
1363 }
1364
1365 int __init s3c2410_dma_init(void)
1366 {
1367         return s3c24xx_dma_init(4, IRQ_DMA0, 0x40);
1368 }
1369
1370 static inline int is_channel_valid(unsigned int channel)
1371 {
1372         return (channel & DMA_CH_VALID);
1373 }
1374
1375 static struct s3c24xx_dma_order *dma_order;
1376
1377
1378 /* s3c2410_dma_map_channel()
1379  *
1380  * turn the virtual channel number into a real, and un-used hardware
1381  * channel.
1382  *
1383  * first, try the dma ordering given to us by either the relevant
1384  * dma code, or the board. Then just find the first usable free
1385  * channel
1386 */
1387
1388 static struct s3c2410_dma_chan *s3c2410_dma_map_channel(int channel)
1389 {
1390         struct s3c24xx_dma_order_ch *ord = NULL;
1391         struct s3c24xx_dma_map *ch_map;
1392         struct s3c2410_dma_chan *dmach;
1393         int ch;
1394
1395         if (dma_sel.map == NULL || channel > dma_sel.map_size)
1396                 return NULL;
1397
1398         ch_map = dma_sel.map + channel;
1399
1400         /* first, try the board mapping */
1401
1402         if (dma_order) {
1403                 ord = &dma_order->channels[channel];
1404
1405                 for (ch = 0; ch < dma_channels; ch++) {
1406                         if (!is_channel_valid(ord->list[ch]))
1407                                 continue;
1408
1409                         if (s3c2410_chans[ord->list[ch]].in_use == 0) {
1410                                 ch = ord->list[ch] & ~DMA_CH_VALID;
1411                                 goto found;
1412                         }
1413                 }
1414
1415                 if (ord->flags & DMA_CH_NEVER)
1416                         return NULL;
1417         }
1418
1419         /* second, search the channel map for first free */
1420
1421         for (ch = 0; ch < dma_channels; ch++) {
1422                 if (!is_channel_valid(ch_map->channels[ch]))
1423                         continue;
1424
1425                 if (s3c2410_chans[ch].in_use == 0) {
1426                         printk("mapped channel %d to %d\n", channel, ch);
1427                         break;
1428                 }
1429         }
1430
1431         if (ch >= dma_channels)
1432                 return NULL;
1433
1434         /* update our channel mapping */
1435
1436  found:
1437         dmach = &s3c2410_chans[ch];
1438         dmach->map = ch_map;
1439         dmach->req_ch = channel;
1440         s3c_dma_chan_map[channel] = dmach;
1441
1442         /* select the channel */
1443
1444         (dma_sel.select)(dmach, ch_map);
1445
1446         return dmach;
1447 }
1448
1449 static int s3c24xx_dma_check_entry(struct s3c24xx_dma_map *map, int ch)
1450 {
1451         return 0;
1452 }
1453
1454 int __init s3c24xx_dma_init_map(struct s3c24xx_dma_selection *sel)
1455 {
1456         struct s3c24xx_dma_map *nmap;
1457         size_t map_sz = sizeof(*nmap) * sel->map_size;
1458         int ptr;
1459
1460         nmap = kmalloc(map_sz, GFP_KERNEL);
1461         if (nmap == NULL)
1462                 return -ENOMEM;
1463
1464         memcpy(nmap, sel->map, map_sz);
1465         memcpy(&dma_sel, sel, sizeof(*sel));
1466
1467         dma_sel.map = nmap;
1468
1469         for (ptr = 0; ptr < sel->map_size; ptr++)
1470                 s3c24xx_dma_check_entry(nmap+ptr, ptr);
1471
1472         return 0;
1473 }
1474
1475 int __init s3c24xx_dma_order_set(struct s3c24xx_dma_order *ord)
1476 {
1477         struct s3c24xx_dma_order *nord = dma_order;
1478
1479         if (nord == NULL)
1480                 nord = kmalloc(sizeof(struct s3c24xx_dma_order), GFP_KERNEL);
1481
1482         if (nord == NULL) {
1483                 printk(KERN_ERR "no memory to store dma channel order\n");
1484                 return -ENOMEM;
1485         }
1486
1487         dma_order = nord;
1488         memcpy(nord, ord, sizeof(struct s3c24xx_dma_order));
1489         return 0;
1490 }