git.oblomov.eu Git - linux-2.6/blob - drivers/dma/dw_dmac.c

   1 /*
   2  * Driver for the Synopsys DesignWare DMA Controller (aka DMACA on
   3  * AVR32 systems.)
   4  *
   5  * Copyright (C) 2007-2008 Atmel Corporation
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11 #include <linux/clk.h>
  12 #include <linux/delay.h>
  13 #include <linux/dmaengine.h>
  14 #include <linux/dma-mapping.h>
  15 #include <linux/init.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/io.h>
  18 #include <linux/mm.h>
  19 #include <linux/module.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/slab.h>
  22
  23 #include "dw_dmac_regs.h"
  24
  25 /*
  26  * This supports the Synopsys "DesignWare AHB Central DMA Controller",
  27  * (DW_ahb_dmac) which is used with various AMBA 2.0 systems (not all
  28  * of which use ARM any more).  See the "Databook" from Synopsys for
  29  * information beyond what licensees probably provide.
  30  *
  31  * The driver has currently been tested only with the Atmel AT32AP7000,
  32  * which does not support descriptor writeback.
  33  */
  34
  35 /* NOTE:  DMS+SMS is system-specific. We should get this information
  36  * from the platform code somehow.
  37  */
  38 #define DWC_DEFAULT_CTLLO       (DWC_CTLL_DST_MSIZE(0)          \
  39                                 | DWC_CTLL_SRC_MSIZE(0)         \
  40                                 | DWC_CTLL_DMS(0)               \
  41                                 | DWC_CTLL_SMS(1)               \
  42                                 | DWC_CTLL_LLP_D_EN             \
  43                                 | DWC_CTLL_LLP_S_EN)
  44
  45 /*
  46  * This is configuration-dependent and usually a funny size like 4095.
  47  * Let's round it down to the nearest power of two.
  48  *
  49  * Note that this is a transfer count, i.e. if we transfer 32-bit
  50  * words, we can do 8192 bytes per descriptor.
  51  *
  52  * This parameter is also system-specific.
  53  */
  54 #define DWC_MAX_COUNT   2048U
  55
  56 /*
  57  * Number of descriptors to allocate for each channel. This should be
  58  * made configurable somehow; preferably, the clients (at least the
  59  * ones using slave transfers) should be able to give us a hint.
  60  */
  61 #define NR_DESCS_PER_CHANNEL    64
  62
  63 /*----------------------------------------------------------------------*/
  64
  65 /*
  66  * Because we're not relying on writeback from the controller (it may not
  67  * even be configured into the core!) we don't need to use dma_pool.  These
  68  * descriptors -- and associated data -- are cacheable.  We do need to make
  69  * sure their dcache entries are written back before handing them off to
  70  * the controller, though.
  71  */
  72
  73 static struct dw_desc *dwc_first_active(struct dw_dma_chan *dwc)
  74 {
  75         return list_entry(dwc->active_list.next, struct dw_desc, desc_node);
  76 }
  77
  78 static struct dw_desc *dwc_first_queued(struct dw_dma_chan *dwc)
  79 {
  80         return list_entry(dwc->queue.next, struct dw_desc, desc_node);
  81 }
  82
  83 static struct dw_desc *dwc_desc_get(struct dw_dma_chan *dwc)
  84 {
  85         struct dw_desc *desc, *_desc;
  86         struct dw_desc *ret = NULL;
  87         unsigned int i = 0;
  88
  89         spin_lock_bh(&dwc->lock);
  90         list_for_each_entry_safe(desc, _desc, &dwc->free_list, desc_node) {
  91                 if (async_tx_test_ack(&desc->txd)) {
  92                         list_del(&desc->desc_node);
  93                         ret = desc;
  94                         break;
  95                 }
  96                 dev_dbg(&dwc->chan.dev, "desc %p not ACKed\n", desc);
  97                 i++;
  98         }
  99         spin_unlock_bh(&dwc->lock);
 100
 101         dev_vdbg(&dwc->chan.dev, "scanned %u descriptors on freelist\n", i);
 102
 103         return ret;
 104 }
 105
 106 static void dwc_sync_desc_for_cpu(struct dw_dma_chan *dwc, struct dw_desc *desc)
 107 {
 108         struct dw_desc  *child;
 109
 110         list_for_each_entry(child, &desc->txd.tx_list, desc_node)
 111                 dma_sync_single_for_cpu(dwc->chan.dev.parent,
 112                                 child->txd.phys, sizeof(child->lli),
 113                                 DMA_TO_DEVICE);
 114         dma_sync_single_for_cpu(dwc->chan.dev.parent,
 115                         desc->txd.phys, sizeof(desc->lli),
 116                         DMA_TO_DEVICE);
 117 }
 118
 119 /*
 120  * Move a descriptor, including any children, to the free list.
 121  * `desc' must not be on any lists.
 122  */
 123 static void dwc_desc_put(struct dw_dma_chan *dwc, struct dw_desc *desc)
 124 {
 125         if (desc) {
 126                 struct dw_desc *child;
 127
 128                 dwc_sync_desc_for_cpu(dwc, desc);
 129
 130                 spin_lock_bh(&dwc->lock);
 131                 list_for_each_entry(child, &desc->txd.tx_list, desc_node)
 132                         dev_vdbg(&dwc->chan.dev,
 133                                         "moving child desc %p to freelist\n",
 134                                         child);
 135                 list_splice_init(&desc->txd.tx_list, &dwc->free_list);
 136                 dev_vdbg(&dwc->chan.dev, "moving desc %p to freelist\n", desc);
 137                 list_add(&desc->desc_node, &dwc->free_list);
 138                 spin_unlock_bh(&dwc->lock);
 139         }
 140 }
 141
 142 /* Called with dwc->lock held and bh disabled */
 143 static dma_cookie_t
 144 dwc_assign_cookie(struct dw_dma_chan *dwc, struct dw_desc *desc)
 145 {
 146         dma_cookie_t cookie = dwc->chan.cookie;
 147
 148         if (++cookie < 0)
 149                 cookie = 1;
 150
 151         dwc->chan.cookie = cookie;
 152         desc->txd.cookie = cookie;
 153
 154         return cookie;
 155 }
 156
 157 /*----------------------------------------------------------------------*/
 158
 159 /* Called with dwc->lock held and bh disabled */
 160 static void dwc_dostart(struct dw_dma_chan *dwc, struct dw_desc *first)
 161 {
 162         struct dw_dma   *dw = to_dw_dma(dwc->chan.device);
 163
 164         /* ASSERT:  channel is idle */
 165         if (dma_readl(dw, CH_EN) & dwc->mask) {
 166                 dev_err(&dwc->chan.dev,
 167                         "BUG: Attempted to start non-idle channel\n");
 168                 dev_err(&dwc->chan.dev,
 169                         "  SAR: 0x%x DAR: 0x%x LLP: 0x%x CTL: 0x%x:%08x\n",
 170                         channel_readl(dwc, SAR),
 171                         channel_readl(dwc, DAR),
 172                         channel_readl(dwc, LLP),
 173                         channel_readl(dwc, CTL_HI),
 174                         channel_readl(dwc, CTL_LO));
 175
 176                 /* The tasklet will hopefully advance the queue... */
 177                 return;
 178         }
 179
 180         channel_writel(dwc, LLP, first->txd.phys);
 181         channel_writel(dwc, CTL_LO,
 182                         DWC_CTLL_LLP_D_EN | DWC_CTLL_LLP_S_EN);
 183         channel_writel(dwc, CTL_HI, 0);
 184         channel_set_bit(dw, CH_EN, dwc->mask);
 185 }
 186
 187 /*----------------------------------------------------------------------*/
 188
 189 static void
 190 dwc_descriptor_complete(struct dw_dma_chan *dwc, struct dw_desc *desc)
 191 {
 192         dma_async_tx_callback           callback;
 193         void                            *param;
 194         struct dma_async_tx_descriptor  *txd = &desc->txd;
 195
 196         dev_vdbg(&dwc->chan.dev, "descriptor %u complete\n", txd->cookie);
 197
 198         dwc->completed = txd->cookie;
 199         callback = txd->callback;
 200         param = txd->callback_param;
 201
 202         dwc_sync_desc_for_cpu(dwc, desc);
 203         list_splice_init(&txd->tx_list, &dwc->free_list);
 204         list_move(&desc->desc_node, &dwc->free_list);
 205
 206         /*
 207          * We use dma_unmap_page() regardless of how the buffers were
 208          * mapped before they were submitted...
 209          */
 210         if (!(txd->flags & DMA_COMPL_SKIP_DEST_UNMAP))
 211                 dma_unmap_page(dwc->chan.dev.parent, desc->lli.dar, desc->len,
 212                                 DMA_FROM_DEVICE);
 213         if (!(txd->flags & DMA_COMPL_SKIP_SRC_UNMAP))
 214                 dma_unmap_page(dwc->chan.dev.parent, desc->lli.sar, desc->len,
 215                                 DMA_TO_DEVICE);
 216
 217         /*
 218          * The API requires that no submissions are done from a
 219          * callback, so we don't need to drop the lock here
 220          */
 221         if (callback)
 222                 callback(param);
 223 }
 224
 225 static void dwc_complete_all(struct dw_dma *dw, struct dw_dma_chan *dwc)
 226 {
 227         struct dw_desc *desc, *_desc;
 228         LIST_HEAD(list);
 229
 230         if (dma_readl(dw, CH_EN) & dwc->mask) {
 231                 dev_err(&dwc->chan.dev,
 232                         "BUG: XFER bit set, but channel not idle!\n");
 233
 234                 /* Try to continue after resetting the channel... */
 235                 channel_clear_bit(dw, CH_EN, dwc->mask);
 236                 while (dma_readl(dw, CH_EN) & dwc->mask)
 237                         cpu_relax();
 238         }
 239
 240         /*
 241          * Submit queued descriptors ASAP, i.e. before we go through
 242          * the completed ones.
 243          */
 244         if (!list_empty(&dwc->queue))
 245                 dwc_dostart(dwc, dwc_first_queued(dwc));
 246         list_splice_init(&dwc->active_list, &list);
 247         list_splice_init(&dwc->queue, &dwc->active_list);
 248
 249         list_for_each_entry_safe(desc, _desc, &list, desc_node)
 250                 dwc_descriptor_complete(dwc, desc);
 251 }
 252
 253 static void dwc_scan_descriptors(struct dw_dma *dw, struct dw_dma_chan *dwc)
 254 {
 255         dma_addr_t llp;
 256         struct dw_desc *desc, *_desc;
 257         struct dw_desc *child;
 258         u32 status_xfer;
 259
 260         /*
 261          * Clear block interrupt flag before scanning so that we don't
 262          * miss any, and read LLP before RAW_XFER to ensure it is
 263          * valid if we decide to scan the list.
 264          */
 265         dma_writel(dw, CLEAR.BLOCK, dwc->mask);
 266         llp = channel_readl(dwc, LLP);
 267         status_xfer = dma_readl(dw, RAW.XFER);
 268
 269         if (status_xfer & dwc->mask) {
 270                 /* Everything we've submitted is done */
 271                 dma_writel(dw, CLEAR.XFER, dwc->mask);
 272                 dwc_complete_all(dw, dwc);
 273                 return;
 274         }
 275
 276         dev_vdbg(&dwc->chan.dev, "scan_descriptors: llp=0x%x\n", llp);
 277
 278         list_for_each_entry_safe(desc, _desc, &dwc->active_list, desc_node) {
 279                 if (desc->lli.llp == llp)
 280                         /* This one is currently in progress */
 281                         return;
 282
 283                 list_for_each_entry(child, &desc->txd.tx_list, desc_node)
 284                         if (child->lli.llp == llp)
 285                                 /* Currently in progress */
 286                                 return;
 287
 288                 /*
 289                  * No descriptors so far seem to be in progress, i.e.
 290                  * this one must be done.
 291                  */
 292                 dwc_descriptor_complete(dwc, desc);
 293         }
 294
 295         dev_err(&dwc->chan.dev,
 296                 "BUG: All descriptors done, but channel not idle!\n");
 297
 298         /* Try to continue after resetting the channel... */
 299         channel_clear_bit(dw, CH_EN, dwc->mask);
 300         while (dma_readl(dw, CH_EN) & dwc->mask)
 301                 cpu_relax();
 302
 303         if (!list_empty(&dwc->queue)) {
 304                 dwc_dostart(dwc, dwc_first_queued(dwc));
 305                 list_splice_init(&dwc->queue, &dwc->active_list);
 306         }
 307 }
 308
 309 static void dwc_dump_lli(struct dw_dma_chan *dwc, struct dw_lli *lli)
 310 {
 311         dev_printk(KERN_CRIT, &dwc->chan.dev,
 312                         "  desc: s0x%x d0x%x l0x%x c0x%x:%x\n",
 313                         lli->sar, lli->dar, lli->llp,
 314                         lli->ctlhi, lli->ctllo);
 315 }
 316
 317 static void dwc_handle_error(struct dw_dma *dw, struct dw_dma_chan *dwc)
 318 {
 319         struct dw_desc *bad_desc;
 320         struct dw_desc *child;
 321
 322         dwc_scan_descriptors(dw, dwc);
 323
 324         /*
 325          * The descriptor currently at the head of the active list is
 326          * borked. Since we don't have any way to report errors, we'll
 327          * just have to scream loudly and try to carry on.
 328          */
 329         bad_desc = dwc_first_active(dwc);
 330         list_del_init(&bad_desc->desc_node);
 331         list_splice_init(&dwc->queue, dwc->active_list.prev);
 332
 333         /* Clear the error flag and try to restart the controller */
 334         dma_writel(dw, CLEAR.ERROR, dwc->mask);
 335         if (!list_empty(&dwc->active_list))
 336                 dwc_dostart(dwc, dwc_first_active(dwc));
 337
 338         /*
 339          * KERN_CRITICAL may seem harsh, but since this only happens
 340          * when someone submits a bad physical address in a
 341          * descriptor, we should consider ourselves lucky that the
 342          * controller flagged an error instead of scribbling over
 343          * random memory locations.
 344          */
 345         dev_printk(KERN_CRIT, &dwc->chan.dev,
 346                         "Bad descriptor submitted for DMA!\n");
 347         dev_printk(KERN_CRIT, &dwc->chan.dev,
 348                         "  cookie: %d\n", bad_desc->txd.cookie);
 349         dwc_dump_lli(dwc, &bad_desc->lli);
 350         list_for_each_entry(child, &bad_desc->txd.tx_list, desc_node)
 351                 dwc_dump_lli(dwc, &child->lli);
 352
 353         /* Pretend the descriptor completed successfully */
 354         dwc_descriptor_complete(dwc, bad_desc);
 355 }
 356
 357 static void dw_dma_tasklet(unsigned long data)
 358 {
 359         struct dw_dma *dw = (struct dw_dma *)data;
 360         struct dw_dma_chan *dwc;
 361         u32 status_block;
 362         u32 status_xfer;
 363         u32 status_err;
 364         int i;
 365
 366         status_block = dma_readl(dw, RAW.BLOCK);
 367         status_xfer = dma_readl(dw, RAW.XFER);
 368         status_err = dma_readl(dw, RAW.ERROR);
 369
 370         dev_vdbg(dw->dma.dev, "tasklet: status_block=%x status_err=%x\n",
 371                         status_block, status_err);
 372
 373         for (i = 0; i < dw->dma.chancnt; i++) {
 374                 dwc = &dw->chan[i];
 375                 spin_lock(&dwc->lock);
 376                 if (status_err & (1 << i))
 377                         dwc_handle_error(dw, dwc);
 378                 else if ((status_block | status_xfer) & (1 << i))
 379                         dwc_scan_descriptors(dw, dwc);
 380                 spin_unlock(&dwc->lock);
 381         }
 382
 383         /*
 384          * Re-enable interrupts. Block Complete interrupts are only
 385          * enabled if the INT_EN bit in the descriptor is set. This
 386          * will trigger a scan before the whole list is done.
 387          */
 388         channel_set_bit(dw, MASK.XFER, dw->all_chan_mask);
 389         channel_set_bit(dw, MASK.BLOCK, dw->all_chan_mask);
 390         channel_set_bit(dw, MASK.ERROR, dw->all_chan_mask);
 391 }
 392
 393 static irqreturn_t dw_dma_interrupt(int irq, void *dev_id)
 394 {
 395         struct dw_dma *dw = dev_id;
 396         u32 status;
 397
 398         dev_vdbg(dw->dma.dev, "interrupt: status=0x%x\n",
 399                         dma_readl(dw, STATUS_INT));
 400
 401         /*
 402          * Just disable the interrupts. We'll turn them back on in the
 403          * softirq handler.
 404          */
 405         channel_clear_bit(dw, MASK.XFER, dw->all_chan_mask);
 406         channel_clear_bit(dw, MASK.BLOCK, dw->all_chan_mask);
 407         channel_clear_bit(dw, MASK.ERROR, dw->all_chan_mask);
 408
 409         status = dma_readl(dw, STATUS_INT);
 410         if (status) {
 411                 dev_err(dw->dma.dev,
 412                         "BUG: Unexpected interrupts pending: 0x%x\n",
 413                         status);
 414
 415                 /* Try to recover */
 416                 channel_clear_bit(dw, MASK.XFER, (1 << 8) - 1);
 417                 channel_clear_bit(dw, MASK.BLOCK, (1 << 8) - 1);
 418                 channel_clear_bit(dw, MASK.SRC_TRAN, (1 << 8) - 1);
 419                 channel_clear_bit(dw, MASK.DST_TRAN, (1 << 8) - 1);
 420                 channel_clear_bit(dw, MASK.ERROR, (1 << 8) - 1);
 421         }
 422
 423         tasklet_schedule(&dw->tasklet);
 424
 425         return IRQ_HANDLED;
 426 }
 427
 428 /*----------------------------------------------------------------------*/
 429
 430 static dma_cookie_t dwc_tx_submit(struct dma_async_tx_descriptor *tx)
 431 {
 432         struct dw_desc          *desc = txd_to_dw_desc(tx);
 433         struct dw_dma_chan      *dwc = to_dw_dma_chan(tx->chan);
 434         dma_cookie_t            cookie;
 435
 436         spin_lock_bh(&dwc->lock);
 437         cookie = dwc_assign_cookie(dwc, desc);
 438
 439         /*
 440          * REVISIT: We should attempt to chain as many descriptors as
 441          * possible, perhaps even appending to those already submitted
 442          * for DMA. But this is hard to do in a race-free manner.
 443          */
 444         if (list_empty(&dwc->active_list)) {
 445                 dev_vdbg(&tx->chan->dev, "tx_submit: started %u\n",
 446                                 desc->txd.cookie);
 447                 dwc_dostart(dwc, desc);
 448                 list_add_tail(&desc->desc_node, &dwc->active_list);
 449         } else {
 450                 dev_vdbg(&tx->chan->dev, "tx_submit: queued %u\n",
 451                                 desc->txd.cookie);
 452
 453                 list_add_tail(&desc->desc_node, &dwc->queue);
 454         }
 455
 456         spin_unlock_bh(&dwc->lock);
 457
 458         return cookie;
 459 }
 460
 461 static struct dma_async_tx_descriptor *
 462 dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
 463                 size_t len, unsigned long flags)
 464 {
 465         struct dw_dma_chan      *dwc = to_dw_dma_chan(chan);
 466         struct dw_desc          *desc;
 467         struct dw_desc          *first;
 468         struct dw_desc          *prev;
 469         size_t                  xfer_count;
 470         size_t                  offset;
 471         unsigned int            src_width;
 472         unsigned int            dst_width;
 473         u32                     ctllo;
 474
 475         dev_vdbg(&chan->dev, "prep_dma_memcpy d0x%x s0x%x l0x%zx f0x%lx\n",
 476                         dest, src, len, flags);
 477
 478         if (unlikely(!len)) {
 479                 dev_dbg(&chan->dev, "prep_dma_memcpy: length is zero!\n");
 480                 return NULL;
 481         }
 482
 483         /*
 484          * We can be a lot more clever here, but this should take care
 485          * of the most common optimization.
 486          */
 487         if (!((src | dest  | len) & 3))
 488                 src_width = dst_width = 2;
 489         else if (!((src | dest | len) & 1))
 490                 src_width = dst_width = 1;
 491         else
 492                 src_width = dst_width = 0;
 493
 494         ctllo = DWC_DEFAULT_CTLLO
 495                         | DWC_CTLL_DST_WIDTH(dst_width)
 496                         | DWC_CTLL_SRC_WIDTH(src_width)
 497                         | DWC_CTLL_DST_INC
 498                         | DWC_CTLL_SRC_INC
 499                         | DWC_CTLL_FC_M2M;
 500         prev = first = NULL;
 501
 502         for (offset = 0; offset < len; offset += xfer_count << src_width) {
 503                 xfer_count = min_t(size_t, (len - offset) >> src_width,
 504                                 DWC_MAX_COUNT);
 505
 506                 desc = dwc_desc_get(dwc);
 507                 if (!desc)
 508                         goto err_desc_get;
 509
 510                 desc->lli.sar = src + offset;
 511                 desc->lli.dar = dest + offset;
 512                 desc->lli.ctllo = ctllo;
 513                 desc->lli.ctlhi = xfer_count;
 514
 515                 if (!first) {
 516                         first = desc;
 517                 } else {
 518                         prev->lli.llp = desc->txd.phys;
 519                         dma_sync_single_for_device(chan->dev.parent,
 520                                         prev->txd.phys, sizeof(prev->lli),
 521                                         DMA_TO_DEVICE);
 522                         list_add_tail(&desc->desc_node,
 523                                         &first->txd.tx_list);
 524                 }
 525                 prev = desc;
 526         }
 527
 528
 529         if (flags & DMA_PREP_INTERRUPT)
 530                 /* Trigger interrupt after last block */
 531                 prev->lli.ctllo |= DWC_CTLL_INT_EN;
 532
 533         prev->lli.llp = 0;
 534         dma_sync_single_for_device(chan->dev.parent,
 535                         prev->txd.phys, sizeof(prev->lli),
 536                         DMA_TO_DEVICE);
 537
 538         first->txd.flags = flags;
 539         first->len = len;
 540
 541         return &first->txd;
 542
 543 err_desc_get:
 544         dwc_desc_put(dwc, first);
 545         return NULL;
 546 }
 547
 548 static struct dma_async_tx_descriptor *
 549 dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
 550                 unsigned int sg_len, enum dma_data_direction direction,
 551                 unsigned long flags)
 552 {
 553         struct dw_dma_chan      *dwc = to_dw_dma_chan(chan);
 554         struct dw_dma_slave     *dws = dwc->dws;
 555         struct dw_desc          *prev;
 556         struct dw_desc          *first;
 557         u32                     ctllo;
 558         dma_addr_t              reg;
 559         unsigned int            reg_width;
 560         unsigned int            mem_width;
 561         unsigned int            i;
 562         struct scatterlist      *sg;
 563         size_t                  total_len = 0;
 564
 565         dev_vdbg(&chan->dev, "prep_dma_slave\n");
 566
 567         if (unlikely(!dws || !sg_len))
 568                 return NULL;
 569
 570         reg_width = dws->slave.reg_width;
 571         prev = first = NULL;
 572
 573         sg_len = dma_map_sg(chan->dev.parent, sgl, sg_len, direction);
 574
 575         switch (direction) {
 576         case DMA_TO_DEVICE:
 577                 ctllo = (DWC_DEFAULT_CTLLO
 578                                 | DWC_CTLL_DST_WIDTH(reg_width)
 579                                 | DWC_CTLL_DST_FIX
 580                                 | DWC_CTLL_SRC_INC
 581                                 | DWC_CTLL_FC_M2P);
 582                 reg = dws->slave.tx_reg;
 583                 for_each_sg(sgl, sg, sg_len, i) {
 584                         struct dw_desc  *desc;
 585                         u32             len;
 586                         u32             mem;
 587
 588                         desc = dwc_desc_get(dwc);
 589                         if (!desc) {
 590                                 dev_err(&chan->dev,
 591                                         "not enough descriptors available\n");
 592                                 goto err_desc_get;
 593                         }
 594
 595                         mem = sg_phys(sg);
 596                         len = sg_dma_len(sg);
 597                         mem_width = 2;
 598                         if (unlikely(mem & 3 || len & 3))
 599                                 mem_width = 0;
 600
 601                         desc->lli.sar = mem;
 602                         desc->lli.dar = reg;
 603                         desc->lli.ctllo = ctllo | DWC_CTLL_SRC_WIDTH(mem_width);
 604                         desc->lli.ctlhi = len >> mem_width;
 605
 606                         if (!first) {
 607                                 first = desc;
 608                         } else {
 609                                 prev->lli.llp = desc->txd.phys;
 610                                 dma_sync_single_for_device(chan->dev.parent,
 611                                                 prev->txd.phys,
 612                                                 sizeof(prev->lli),
 613                                                 DMA_TO_DEVICE);
 614                                 list_add_tail(&desc->desc_node,
 615                                                 &first->txd.tx_list);
 616                         }
 617                         prev = desc;
 618                         total_len += len;
 619                 }
 620                 break;
 621         case DMA_FROM_DEVICE:
 622                 ctllo = (DWC_DEFAULT_CTLLO
 623                                 | DWC_CTLL_SRC_WIDTH(reg_width)
 624                                 | DWC_CTLL_DST_INC
 625                                 | DWC_CTLL_SRC_FIX
 626                                 | DWC_CTLL_FC_P2M);
 627
 628                 reg = dws->slave.rx_reg;
 629                 for_each_sg(sgl, sg, sg_len, i) {
 630                         struct dw_desc  *desc;
 631                         u32             len;
 632                         u32             mem;
 633
 634                         desc = dwc_desc_get(dwc);
 635                         if (!desc) {
 636                                 dev_err(&chan->dev,
 637                                         "not enough descriptors available\n");
 638                                 goto err_desc_get;
 639                         }
 640
 641                         mem = sg_phys(sg);
 642                         len = sg_dma_len(sg);
 643                         mem_width = 2;
 644                         if (unlikely(mem & 3 || len & 3))
 645                                 mem_width = 0;
 646
 647                         desc->lli.sar = reg;
 648                         desc->lli.dar = mem;
 649                         desc->lli.ctllo = ctllo | DWC_CTLL_DST_WIDTH(mem_width);
 650                         desc->lli.ctlhi = len >> reg_width;
 651
 652                         if (!first) {
 653                                 first = desc;
 654                         } else {
 655                                 prev->lli.llp = desc->txd.phys;
 656                                 dma_sync_single_for_device(chan->dev.parent,
 657                                                 prev->txd.phys,
 658                                                 sizeof(prev->lli),
 659                                                 DMA_TO_DEVICE);
 660                                 list_add_tail(&desc->desc_node,
 661                                                 &first->txd.tx_list);
 662                         }
 663                         prev = desc;
 664                         total_len += len;
 665                 }
 666                 break;
 667         default:
 668                 return NULL;
 669         }
 670
 671         if (flags & DMA_PREP_INTERRUPT)
 672                 /* Trigger interrupt after last block */
 673                 prev->lli.ctllo |= DWC_CTLL_INT_EN;
 674
 675         prev->lli.llp = 0;
 676         dma_sync_single_for_device(chan->dev.parent,
 677                         prev->txd.phys, sizeof(prev->lli),
 678                         DMA_TO_DEVICE);
 679
 680         first->len = total_len;
 681
 682         return &first->txd;
 683
 684 err_desc_get:
 685         dwc_desc_put(dwc, first);
 686         return NULL;
 687 }
 688
 689 static void dwc_terminate_all(struct dma_chan *chan)
 690 {
 691         struct dw_dma_chan      *dwc = to_dw_dma_chan(chan);
 692         struct dw_dma           *dw = to_dw_dma(chan->device);
 693         struct dw_desc          *desc, *_desc;
 694         LIST_HEAD(list);
 695
 696         /*
 697          * This is only called when something went wrong elsewhere, so
 698          * we don't really care about the data. Just disable the
 699          * channel. We still have to poll the channel enable bit due
 700          * to AHB/HSB limitations.
 701          */
 702         spin_lock_bh(&dwc->lock);
 703
 704         channel_clear_bit(dw, CH_EN, dwc->mask);
 705
 706         while (dma_readl(dw, CH_EN) & dwc->mask)
 707                 cpu_relax();
 708
 709         /* active_list entries will end up before queued entries */
 710         list_splice_init(&dwc->queue, &list);
 711         list_splice_init(&dwc->active_list, &list);
 712
 713         spin_unlock_bh(&dwc->lock);
 714
 715         /* Flush all pending and queued descriptors */
 716         list_for_each_entry_safe(desc, _desc, &list, desc_node)
 717                 dwc_descriptor_complete(dwc, desc);
 718 }
 719
 720 static enum dma_status
 721 dwc_is_tx_complete(struct dma_chan *chan,
 722                 dma_cookie_t cookie,
 723                 dma_cookie_t *done, dma_cookie_t *used)
 724 {
 725         struct dw_dma_chan      *dwc = to_dw_dma_chan(chan);
 726         dma_cookie_t            last_used;
 727         dma_cookie_t            last_complete;
 728         int                     ret;
 729
 730         last_complete = dwc->completed;
 731         last_used = chan->cookie;
 732
 733         ret = dma_async_is_complete(cookie, last_complete, last_used);
 734         if (ret != DMA_SUCCESS) {
 735                 dwc_scan_descriptors(to_dw_dma(chan->device), dwc);
 736
 737                 last_complete = dwc->completed;
 738                 last_used = chan->cookie;
 739
 740                 ret = dma_async_is_complete(cookie, last_complete, last_used);
 741         }
 742
 743         if (done)
 744                 *done = last_complete;
 745         if (used)
 746                 *used = last_used;
 747
 748         return ret;
 749 }
 750
 751 static void dwc_issue_pending(struct dma_chan *chan)
 752 {
 753         struct dw_dma_chan      *dwc = to_dw_dma_chan(chan);
 754
 755         spin_lock_bh(&dwc->lock);
 756         if (!list_empty(&dwc->queue))
 757                 dwc_scan_descriptors(to_dw_dma(chan->device), dwc);
 758         spin_unlock_bh(&dwc->lock);
 759 }
 760
 761 static int dwc_alloc_chan_resources(struct dma_chan *chan,
 762                 struct dma_client *client)
 763 {
 764         struct dw_dma_chan      *dwc = to_dw_dma_chan(chan);
 765         struct dw_dma           *dw = to_dw_dma(chan->device);
 766         struct dw_desc          *desc;
 767         struct dma_slave        *slave;
 768         struct dw_dma_slave     *dws;
 769         int                     i;
 770         u32                     cfghi;
 771         u32                     cfglo;
 772
 773         dev_vdbg(&chan->dev, "alloc_chan_resources\n");
 774
 775         /* Channels doing slave DMA can only handle one client. */
 776         if (dwc->dws || client->slave) {
 777                 if (chan->client_count)
 778                         return -EBUSY;
 779         }
 780
 781         /* ASSERT:  channel is idle */
 782         if (dma_readl(dw, CH_EN) & dwc->mask) {
 783                 dev_dbg(&chan->dev, "DMA channel not idle?\n");
 784                 return -EIO;
 785         }
 786
 787         dwc->completed = chan->cookie = 1;
 788
 789         cfghi = DWC_CFGH_FIFO_MODE;
 790         cfglo = 0;
 791
 792         slave = client->slave;
 793         if (slave) {
 794                 /*
 795                  * We need controller-specific data to set up slave
 796                  * transfers.
 797                  */
 798                 BUG_ON(!slave->dma_dev || slave->dma_dev != dw->dma.dev);
 799
 800                 dws = container_of(slave, struct dw_dma_slave, slave);
 801
 802                 dwc->dws = dws;
 803                 cfghi = dws->cfg_hi;
 804                 cfglo = dws->cfg_lo;
 805         } else {
 806                 dwc->dws = NULL;
 807         }
 808
 809         channel_writel(dwc, CFG_LO, cfglo);
 810         channel_writel(dwc, CFG_HI, cfghi);
 811
 812         /*
 813          * NOTE: some controllers may have additional features that we
 814          * need to initialize here, like "scatter-gather" (which
 815          * doesn't mean what you think it means), and status writeback.
 816          */
 817
 818         spin_lock_bh(&dwc->lock);
 819         i = dwc->descs_allocated;
 820         while (dwc->descs_allocated < NR_DESCS_PER_CHANNEL) {
 821                 spin_unlock_bh(&dwc->lock);
 822
 823                 desc = kzalloc(sizeof(struct dw_desc), GFP_KERNEL);
 824                 if (!desc) {
 825                         dev_info(&chan->dev,
 826                                 "only allocated %d descriptors\n", i);
 827                         spin_lock_bh(&dwc->lock);
 828                         break;
 829                 }
 830
 831                 dma_async_tx_descriptor_init(&desc->txd, chan);
 832                 desc->txd.tx_submit = dwc_tx_submit;
 833                 desc->txd.flags = DMA_CTRL_ACK;
 834                 INIT_LIST_HEAD(&desc->txd.tx_list);
 835                 desc->txd.phys = dma_map_single(chan->dev.parent, &desc->lli,
 836                                 sizeof(desc->lli), DMA_TO_DEVICE);
 837                 dwc_desc_put(dwc, desc);
 838
 839                 spin_lock_bh(&dwc->lock);
 840                 i = ++dwc->descs_allocated;
 841         }
 842
 843         /* Enable interrupts */
 844         channel_set_bit(dw, MASK.XFER, dwc->mask);
 845         channel_set_bit(dw, MASK.BLOCK, dwc->mask);
 846         channel_set_bit(dw, MASK.ERROR, dwc->mask);
 847
 848         spin_unlock_bh(&dwc->lock);
 849
 850         dev_dbg(&chan->dev,
 851                 "alloc_chan_resources allocated %d descriptors\n", i);
 852
 853         return i;
 854 }
 855
 856 static void dwc_free_chan_resources(struct dma_chan *chan)
 857 {
 858         struct dw_dma_chan      *dwc = to_dw_dma_chan(chan);
 859         struct dw_dma           *dw = to_dw_dma(chan->device);
 860         struct dw_desc          *desc, *_desc;
 861         LIST_HEAD(list);
 862
 863         dev_dbg(&chan->dev, "free_chan_resources (descs allocated=%u)\n",
 864                         dwc->descs_allocated);
 865
 866         /* ASSERT:  channel is idle */
 867         BUG_ON(!list_empty(&dwc->active_list));
 868         BUG_ON(!list_empty(&dwc->queue));
 869         BUG_ON(dma_readl(to_dw_dma(chan->device), CH_EN) & dwc->mask);
 870
 871         spin_lock_bh(&dwc->lock);
 872         list_splice_init(&dwc->free_list, &list);
 873         dwc->descs_allocated = 0;
 874         dwc->dws = NULL;
 875
 876         /* Disable interrupts */
 877         channel_clear_bit(dw, MASK.XFER, dwc->mask);
 878         channel_clear_bit(dw, MASK.BLOCK, dwc->mask);
 879         channel_clear_bit(dw, MASK.ERROR, dwc->mask);
 880
 881         spin_unlock_bh(&dwc->lock);
 882
 883         list_for_each_entry_safe(desc, _desc, &list, desc_node) {
 884                 dev_vdbg(&chan->dev, "  freeing descriptor %p\n", desc);
 885                 dma_unmap_single(chan->dev.parent, desc->txd.phys,
 886                                 sizeof(desc->lli), DMA_TO_DEVICE);
 887                 kfree(desc);
 888         }
 889
 890         dev_vdbg(&chan->dev, "free_chan_resources done\n");
 891 }
 892
 893 /*----------------------------------------------------------------------*/
 894
 895 static void dw_dma_off(struct dw_dma *dw)
 896 {
 897         dma_writel(dw, CFG, 0);
 898
 899         channel_clear_bit(dw, MASK.XFER, dw->all_chan_mask);
 900         channel_clear_bit(dw, MASK.BLOCK, dw->all_chan_mask);
 901         channel_clear_bit(dw, MASK.SRC_TRAN, dw->all_chan_mask);
 902         channel_clear_bit(dw, MASK.DST_TRAN, dw->all_chan_mask);
 903         channel_clear_bit(dw, MASK.ERROR, dw->all_chan_mask);
 904
 905         while (dma_readl(dw, CFG) & DW_CFG_DMA_EN)
 906                 cpu_relax();
 907 }
 908
 909 static int __init dw_probe(struct platform_device *pdev)
 910 {
 911         struct dw_dma_platform_data *pdata;
 912         struct resource         *io;
 913         struct dw_dma           *dw;
 914         size_t                  size;
 915         int                     irq;
 916         int                     err;
 917         int                     i;
 918
 919         pdata = pdev->dev.platform_data;
 920         if (!pdata || pdata->nr_channels > DW_DMA_MAX_NR_CHANNELS)
 921                 return -EINVAL;
 922
 923         io = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 924         if (!io)
 925                 return -EINVAL;
 926
 927         irq = platform_get_irq(pdev, 0);
 928         if (irq < 0)
 929                 return irq;
 930
 931         size = sizeof(struct dw_dma);
 932         size += pdata->nr_channels * sizeof(struct dw_dma_chan);
 933         dw = kzalloc(size, GFP_KERNEL);
 934         if (!dw)
 935                 return -ENOMEM;
 936
 937         if (!request_mem_region(io->start, DW_REGLEN, pdev->dev.driver->name)) {
 938                 err = -EBUSY;
 939                 goto err_kfree;
 940         }
 941
 942         memset(dw, 0, sizeof *dw);
 943
 944         dw->regs = ioremap(io->start, DW_REGLEN);
 945         if (!dw->regs) {
 946                 err = -ENOMEM;
 947                 goto err_release_r;
 948         }
 949
 950         dw->clk = clk_get(&pdev->dev, "hclk");
 951         if (IS_ERR(dw->clk)) {
 952                 err = PTR_ERR(dw->clk);
 953                 goto err_clk;
 954         }
 955         clk_enable(dw->clk);
 956
 957         /* force dma off, just in case */
 958         dw_dma_off(dw);
 959
 960         err = request_irq(irq, dw_dma_interrupt, 0, "dw_dmac", dw);
 961         if (err)
 962                 goto err_irq;
 963
 964         platform_set_drvdata(pdev, dw);
 965
 966         tasklet_init(&dw->tasklet, dw_dma_tasklet, (unsigned long)dw);
 967
 968         dw->all_chan_mask = (1 << pdata->nr_channels) - 1;
 969
 970         INIT_LIST_HEAD(&dw->dma.channels);
 971         for (i = 0; i < pdata->nr_channels; i++, dw->dma.chancnt++) {
 972                 struct dw_dma_chan      *dwc = &dw->chan[i];
 973
 974                 dwc->chan.device = &dw->dma;
 975                 dwc->chan.cookie = dwc->completed = 1;
 976                 dwc->chan.chan_id = i;
 977                 list_add_tail(&dwc->chan.device_node, &dw->dma.channels);
 978
 979                 dwc->ch_regs = &__dw_regs(dw)->CHAN[i];
 980                 spin_lock_init(&dwc->lock);
 981                 dwc->mask = 1 << i;
 982
 983                 INIT_LIST_HEAD(&dwc->active_list);
 984                 INIT_LIST_HEAD(&dwc->queue);
 985                 INIT_LIST_HEAD(&dwc->free_list);
 986
 987                 channel_clear_bit(dw, CH_EN, dwc->mask);
 988         }
 989
 990         /* Clear/disable all interrupts on all channels. */
 991         dma_writel(dw, CLEAR.XFER, dw->all_chan_mask);
 992         dma_writel(dw, CLEAR.BLOCK, dw->all_chan_mask);
 993         dma_writel(dw, CLEAR.SRC_TRAN, dw->all_chan_mask);
 994         dma_writel(dw, CLEAR.DST_TRAN, dw->all_chan_mask);
 995         dma_writel(dw, CLEAR.ERROR, dw->all_chan_mask);
 996
 997         channel_clear_bit(dw, MASK.XFER, dw->all_chan_mask);
 998         channel_clear_bit(dw, MASK.BLOCK, dw->all_chan_mask);
 999         channel_clear_bit(dw, MASK.SRC_TRAN, dw->all_chan_mask);
1000         channel_clear_bit(dw, MASK.DST_TRAN, dw->all_chan_mask);
1001         channel_clear_bit(dw, MASK.ERROR, dw->all_chan_mask);
1002
1003         dma_cap_set(DMA_MEMCPY, dw->dma.cap_mask);
1004         dma_cap_set(DMA_SLAVE, dw->dma.cap_mask);
1005         dw->dma.dev = &pdev->dev;
1006         dw->dma.device_alloc_chan_resources = dwc_alloc_chan_resources;
1007         dw->dma.device_free_chan_resources = dwc_free_chan_resources;
1008
1009         dw->dma.device_prep_dma_memcpy = dwc_prep_dma_memcpy;
1010
1011         dw->dma.device_prep_slave_sg = dwc_prep_slave_sg;
1012         dw->dma.device_terminate_all = dwc_terminate_all;
1013
1014         dw->dma.device_is_tx_complete = dwc_is_tx_complete;
1015         dw->dma.device_issue_pending = dwc_issue_pending;
1016
1017         dma_writel(dw, CFG, DW_CFG_DMA_EN);
1018
1019         printk(KERN_INFO "%s: DesignWare DMA Controller, %d channels\n",
1020                         pdev->dev.bus_id, dw->dma.chancnt);
1021
1022         dma_async_device_register(&dw->dma);
1023
1024         return 0;
1025
1026 err_irq:
1027         clk_disable(dw->clk);
1028         clk_put(dw->clk);
1029 err_clk:
1030         iounmap(dw->regs);
1031         dw->regs = NULL;
1032 err_release_r:
1033         release_resource(io);
1034 err_kfree:
1035         kfree(dw);
1036         return err;
1037 }
1038
1039 static int __exit dw_remove(struct platform_device *pdev)
1040 {
1041         struct dw_dma           *dw = platform_get_drvdata(pdev);
1042         struct dw_dma_chan      *dwc, *_dwc;
1043         struct resource         *io;
1044
1045         dw_dma_off(dw);
1046         dma_async_device_unregister(&dw->dma);
1047
1048         free_irq(platform_get_irq(pdev, 0), dw);
1049         tasklet_kill(&dw->tasklet);
1050
1051         list_for_each_entry_safe(dwc, _dwc, &dw->dma.channels,
1052                         chan.device_node) {
1053                 list_del(&dwc->chan.device_node);
1054                 channel_clear_bit(dw, CH_EN, dwc->mask);
1055         }
1056
1057         clk_disable(dw->clk);
1058         clk_put(dw->clk);
1059
1060         iounmap(dw->regs);
1061         dw->regs = NULL;
1062
1063         io = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1064         release_mem_region(io->start, DW_REGLEN);
1065
1066         kfree(dw);
1067
1068         return 0;
1069 }
1070
1071 static void dw_shutdown(struct platform_device *pdev)
1072 {
1073         struct dw_dma   *dw = platform_get_drvdata(pdev);
1074
1075         dw_dma_off(platform_get_drvdata(pdev));
1076         clk_disable(dw->clk);
1077 }
1078
1079 static int dw_suspend_late(struct platform_device *pdev, pm_message_t mesg)
1080 {
1081         struct dw_dma   *dw = platform_get_drvdata(pdev);
1082
1083         dw_dma_off(platform_get_drvdata(pdev));
1084         clk_disable(dw->clk);
1085         return 0;
1086 }
1087
1088 static int dw_resume_early(struct platform_device *pdev)
1089 {
1090         struct dw_dma   *dw = platform_get_drvdata(pdev);
1091
1092         clk_enable(dw->clk);
1093         dma_writel(dw, CFG, DW_CFG_DMA_EN);
1094         return 0;
1095
1096 }
1097
1098 static struct platform_driver dw_driver = {
1099         .remove         = __exit_p(dw_remove),
1100         .shutdown       = dw_shutdown,
1101         .suspend_late   = dw_suspend_late,
1102         .resume_early   = dw_resume_early,
1103         .driver = {
1104                 .name   = "dw_dmac",
1105         },
1106 };
1107
1108 static int __init dw_init(void)
1109 {
1110         return platform_driver_probe(&dw_driver, dw_probe);
1111 }
1112 module_init(dw_init);
1113
1114 static void __exit dw_exit(void)
1115 {
1116         platform_driver_unregister(&dw_driver);
1117 }
1118 module_exit(dw_exit);
1119
1120 MODULE_LICENSE("GPL v2");
1121 MODULE_DESCRIPTION("Synopsys DesignWare DMA Controller driver");
1122 MODULE_AUTHOR("Haavard Skinnemoen <haavard.skinnemoen@atmel.com>");