kernel/drivers/dma/timb_dma.c

   1 /*
   2  * timb_dma.c timberdale FPGA DMA driver
   3  * Copyright (c) 2010 Intel Corporation
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  */
  14
  15 /* Supports:
  16  * Timberdale FPGA DMA engine
  17  */
  18
  19 #include <linux/dmaengine.h>
  20 #include <linux/dma-mapping.h>
  21 #include <linux/init.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/io.h>
  24 #include <linux/module.h>
  25 #include <linux/platform_device.h>
  26 #include <linux/slab.h>
  27
  28 #include <linux/timb_dma.h>
  29
  30 #include "dmaengine.h"
  31
  32 #define DRIVER_NAME "timb-dma"
  33
  34 /* Global DMA registers */
  35 #define TIMBDMA_ACR             0x34
  36 #define TIMBDMA_32BIT_ADDR      0x01
  37
  38 #define TIMBDMA_ISR             0x080000
  39 #define TIMBDMA_IPR             0x080004
  40 #define TIMBDMA_IER             0x080008
  41
  42 /* Channel specific registers */
  43 /* RX instances base addresses are 0x00, 0x40, 0x80 ...
  44  * TX instances base addresses are 0x18, 0x58, 0x98 ...
  45  */
  46 #define TIMBDMA_INSTANCE_OFFSET         0x40
  47 #define TIMBDMA_INSTANCE_TX_OFFSET      0x18
  48
  49 /* RX registers, relative the instance base */
  50 #define TIMBDMA_OFFS_RX_DHAR    0x00
  51 #define TIMBDMA_OFFS_RX_DLAR    0x04
  52 #define TIMBDMA_OFFS_RX_LR      0x0C
  53 #define TIMBDMA_OFFS_RX_BLR     0x10
  54 #define TIMBDMA_OFFS_RX_ER      0x14
  55 #define TIMBDMA_RX_EN           0x01
  56 /* bytes per Row, video specific register
  57  * which is placed after the TX registers...
  58  */
  59 #define TIMBDMA_OFFS_RX_BPRR    0x30
  60
  61 /* TX registers, relative the instance base */
  62 #define TIMBDMA_OFFS_TX_DHAR    0x00
  63 #define TIMBDMA_OFFS_TX_DLAR    0x04
  64 #define TIMBDMA_OFFS_TX_BLR     0x0C
  65 #define TIMBDMA_OFFS_TX_LR      0x14
  66
  67
  68 #define TIMB_DMA_DESC_SIZE      8
  69
  70 struct timb_dma_desc {
  71         struct list_head                desc_node;
  72         struct dma_async_tx_descriptor  txd;
  73         u8                              *desc_list;
  74         unsigned int                    desc_list_len;
  75         bool                            interrupt;
  76 };
  77
  78 struct timb_dma_chan {
  79         struct dma_chan         chan;
  80         void __iomem            *membase;
  81         spinlock_t              lock; /* Used to protect data structures,
  82                                         especially the lists and descriptors,
  83                                         from races between the tasklet and calls
  84                                         from above */
  85         bool                    ongoing;
  86         struct list_head        active_list;
  87         struct list_head        queue;
  88         struct list_head        free_list;
  89         unsigned int            bytes_per_line;
  90         enum dma_transfer_direction     direction;
  91         unsigned int            descs; /* Descriptors to allocate */
  92         unsigned int            desc_elems; /* number of elems per descriptor */
  93 };
  94
  95 struct timb_dma {
  96         struct dma_device       dma;
  97         void __iomem            *membase;
  98         struct tasklet_struct   tasklet;
  99         struct timb_dma_chan    channels[0];
 100 };
 101
 102 static struct device *chan2dev(struct dma_chan *chan)
 103 {
 104         return &chan->dev->device;
 105 }
 106 static struct device *chan2dmadev(struct dma_chan *chan)
 107 {
 108         return chan2dev(chan)->parent->parent;
 109 }
 110
 111 static struct timb_dma *tdchantotd(struct timb_dma_chan *td_chan)
 112 {
 113         int id = td_chan->chan.chan_id;
 114         return (struct timb_dma *)((u8 *)td_chan -
 115                 id * sizeof(struct timb_dma_chan) - sizeof(struct timb_dma));
 116 }
 117
 118 /* Must be called with the spinlock held */
 119 static void __td_enable_chan_irq(struct timb_dma_chan *td_chan)
 120 {
 121         int id = td_chan->chan.chan_id;
 122         struct timb_dma *td = tdchantotd(td_chan);
 123         u32 ier;
 124
 125         /* enable interrupt for this channel */
 126         ier = ioread32(td->membase + TIMBDMA_IER);
 127         ier |= 1 << id;
 128         dev_dbg(chan2dev(&td_chan->chan), "Enabling irq: %d, IER: 0x%x\n", id,
 129                 ier);
 130         iowrite32(ier, td->membase + TIMBDMA_IER);
 131 }
 132
 133 /* Should be called with the spinlock held */
 134 static bool __td_dma_done_ack(struct timb_dma_chan *td_chan)
 135 {
 136         int id = td_chan->chan.chan_id;
 137         struct timb_dma *td = (struct timb_dma *)((u8 *)td_chan -
 138                 id * sizeof(struct timb_dma_chan) - sizeof(struct timb_dma));
 139         u32 isr;
 140         bool done = false;
 141
 142         dev_dbg(chan2dev(&td_chan->chan), "Checking irq: %d, td: %p\n", id, td);
 143
 144         isr = ioread32(td->membase + TIMBDMA_ISR) & (1 << id);
 145         if (isr) {
 146                 iowrite32(isr, td->membase + TIMBDMA_ISR);
 147                 done = true;
 148         }
 149
 150         return done;
 151 }
 152
 153 static int td_fill_desc(struct timb_dma_chan *td_chan, u8 *dma_desc,
 154         struct scatterlist *sg, bool last)
 155 {
 156         if (sg_dma_len(sg) > USHRT_MAX) {
 157                 dev_err(chan2dev(&td_chan->chan), "Too big sg element\n");
 158                 return -EINVAL;
 159         }
 160
 161         /* length must be word aligned */
 162         if (sg_dma_len(sg) % sizeof(u32)) {
 163                 dev_err(chan2dev(&td_chan->chan), "Incorrect length: %d\n",
 164                         sg_dma_len(sg));
 165                 return -EINVAL;
 166         }
 167
 168         dev_dbg(chan2dev(&td_chan->chan), "desc: %p, addr: 0x%llx\n",
 169                 dma_desc, (unsigned long long)sg_dma_address(sg));
 170
 171         dma_desc[7] = (sg_dma_address(sg) >> 24) & 0xff;
 172         dma_desc[6] = (sg_dma_address(sg) >> 16) & 0xff;
 173         dma_desc[5] = (sg_dma_address(sg) >> 8) & 0xff;
 174         dma_desc[4] = (sg_dma_address(sg) >> 0) & 0xff;
 175
 176         dma_desc[3] = (sg_dma_len(sg) >> 8) & 0xff;
 177         dma_desc[2] = (sg_dma_len(sg) >> 0) & 0xff;
 178
 179         dma_desc[1] = 0x00;
 180         dma_desc[0] = 0x21 | (last ? 0x02 : 0); /* tran, valid */
 181
 182         return 0;
 183 }
 184
 185 /* Must be called with the spinlock held */
 186 static void __td_start_dma(struct timb_dma_chan *td_chan)
 187 {
 188         struct timb_dma_desc *td_desc;
 189
 190         if (td_chan->ongoing) {
 191                 dev_err(chan2dev(&td_chan->chan),
 192                         "Transfer already ongoing\n");
 193                 return;
 194         }
 195
 196         td_desc = list_entry(td_chan->active_list.next, struct timb_dma_desc,
 197                 desc_node);
 198
 199         dev_dbg(chan2dev(&td_chan->chan),
 200                 "td_chan: %p, chan: %d, membase: %p\n",
 201                 td_chan, td_chan->chan.chan_id, td_chan->membase);
 202
 203         if (td_chan->direction == DMA_DEV_TO_MEM) {
 204
 205                 /* descriptor address */
 206                 iowrite32(0, td_chan->membase + TIMBDMA_OFFS_RX_DHAR);
 207                 iowrite32(td_desc->txd.phys, td_chan->membase +
 208                         TIMBDMA_OFFS_RX_DLAR);
 209                 /* Bytes per line */
 210                 iowrite32(td_chan->bytes_per_line, td_chan->membase +
 211                         TIMBDMA_OFFS_RX_BPRR);
 212                 /* enable RX */
 213                 iowrite32(TIMBDMA_RX_EN, td_chan->membase + TIMBDMA_OFFS_RX_ER);
 214         } else {
 215                 /* address high */
 216                 iowrite32(0, td_chan->membase + TIMBDMA_OFFS_TX_DHAR);
 217                 iowrite32(td_desc->txd.phys, td_chan->membase +
 218                         TIMBDMA_OFFS_TX_DLAR);
 219         }
 220
 221         td_chan->ongoing = true;
 222
 223         if (td_desc->interrupt)
 224                 __td_enable_chan_irq(td_chan);
 225 }
 226
 227 static void __td_finish(struct timb_dma_chan *td_chan)
 228 {
 229         dma_async_tx_callback           callback;
 230         void                            *param;
 231         struct dma_async_tx_descriptor  *txd;
 232         struct timb_dma_desc            *td_desc;
 233
 234         /* can happen if the descriptor is canceled */
 235         if (list_empty(&td_chan->active_list))
 236                 return;
 237
 238         td_desc = list_entry(td_chan->active_list.next, struct timb_dma_desc,
 239                 desc_node);
 240         txd = &td_desc->txd;
 241
 242         dev_dbg(chan2dev(&td_chan->chan), "descriptor %u complete\n",
 243                 txd->cookie);
 244
 245         /* make sure to stop the transfer */
 246         if (td_chan->direction == DMA_DEV_TO_MEM)
 247                 iowrite32(0, td_chan->membase + TIMBDMA_OFFS_RX_ER);
 248 /* Currently no support for stopping DMA transfers
 249         else
 250                 iowrite32(0, td_chan->membase + TIMBDMA_OFFS_TX_DLAR);
 251 */
 252         dma_cookie_complete(txd);
 253         td_chan->ongoing = false;
 254
 255         callback = txd->callback;
 256         param = txd->callback_param;
 257
 258         list_move(&td_desc->desc_node, &td_chan->free_list);
 259
 260         dma_descriptor_unmap(txd);
 261         /*
 262          * The API requires that no submissions are done from a
 263          * callback, so we don't need to drop the lock here
 264          */
 265         if (callback)
 266                 callback(param);
 267 }
 268
 269 static u32 __td_ier_mask(struct timb_dma *td)
 270 {
 271         int i;
 272         u32 ret = 0;
 273
 274         for (i = 0; i < td->dma.chancnt; i++) {
 275                 struct timb_dma_chan *td_chan = td->channels + i;
 276                 if (td_chan->ongoing) {
 277                         struct timb_dma_desc *td_desc =
 278                                 list_entry(td_chan->active_list.next,
 279                                 struct timb_dma_desc, desc_node);
 280                         if (td_desc->interrupt)
 281                                 ret |= 1 << i;
 282                 }
 283         }
 284
 285         return ret;
 286 }
 287
 288 static void __td_start_next(struct timb_dma_chan *td_chan)
 289 {
 290         struct timb_dma_desc *td_desc;
 291
 292         BUG_ON(list_empty(&td_chan->queue));
 293         BUG_ON(td_chan->ongoing);
 294
 295         td_desc = list_entry(td_chan->queue.next, struct timb_dma_desc,
 296                 desc_node);
 297
 298         dev_dbg(chan2dev(&td_chan->chan), "%s: started %u\n",
 299                 __func__, td_desc->txd.cookie);
 300
 301         list_move(&td_desc->desc_node, &td_chan->active_list);
 302         __td_start_dma(td_chan);
 303 }
 304
 305 static dma_cookie_t td_tx_submit(struct dma_async_tx_descriptor *txd)
 306 {
 307         struct timb_dma_desc *td_desc = container_of(txd, struct timb_dma_desc,
 308                 txd);
 309         struct timb_dma_chan *td_chan = container_of(txd->chan,
 310                 struct timb_dma_chan, chan);
 311         dma_cookie_t cookie;
 312
 313         spin_lock_bh(&td_chan->lock);
 314         cookie = dma_cookie_assign(txd);
 315
 316         if (list_empty(&td_chan->active_list)) {
 317                 dev_dbg(chan2dev(txd->chan), "%s: started %u\n", __func__,
 318                         txd->cookie);
 319                 list_add_tail(&td_desc->desc_node, &td_chan->active_list);
 320                 __td_start_dma(td_chan);
 321         } else {
 322                 dev_dbg(chan2dev(txd->chan), "tx_submit: queued %u\n",
 323                         txd->cookie);
 324
 325                 list_add_tail(&td_desc->desc_node, &td_chan->queue);
 326         }
 327
 328         spin_unlock_bh(&td_chan->lock);
 329
 330         return cookie;
 331 }
 332
 333 static struct timb_dma_desc *td_alloc_init_desc(struct timb_dma_chan *td_chan)
 334 {
 335         struct dma_chan *chan = &td_chan->chan;
 336         struct timb_dma_desc *td_desc;
 337         int err;
 338
 339         td_desc = kzalloc(sizeof(struct timb_dma_desc), GFP_KERNEL);
 340         if (!td_desc) {
 341                 dev_err(chan2dev(chan), "Failed to alloc descriptor\n");
 342                 goto out;
 343         }
 344
 345         td_desc->desc_list_len = td_chan->desc_elems * TIMB_DMA_DESC_SIZE;
 346
 347         td_desc->desc_list = kzalloc(td_desc->desc_list_len, GFP_KERNEL);
 348         if (!td_desc->desc_list) {
 349                 dev_err(chan2dev(chan), "Failed to alloc descriptor\n");
 350                 goto err;
 351         }
 352
 353         dma_async_tx_descriptor_init(&td_desc->txd, chan);
 354         td_desc->txd.tx_submit = td_tx_submit;
 355         td_desc->txd.flags = DMA_CTRL_ACK;
 356
 357         td_desc->txd.phys = dma_map_single(chan2dmadev(chan),
 358                 td_desc->desc_list, td_desc->desc_list_len, DMA_TO_DEVICE);
 359
 360         err = dma_mapping_error(chan2dmadev(chan), td_desc->txd.phys);
 361         if (err) {
 362                 dev_err(chan2dev(chan), "DMA mapping error: %d\n", err);
 363                 goto err;
 364         }
 365
 366         return td_desc;
 367 err:
 368         kfree(td_desc->desc_list);
 369         kfree(td_desc);
 370 out:
 371         return NULL;
 372
 373 }
 374
 375 static void td_free_desc(struct timb_dma_desc *td_desc)
 376 {
 377         dev_dbg(chan2dev(td_desc->txd.chan), "Freeing desc: %p\n", td_desc);
 378         dma_unmap_single(chan2dmadev(td_desc->txd.chan), td_desc->txd.phys,
 379                 td_desc->desc_list_len, DMA_TO_DEVICE);
 380
 381         kfree(td_desc->desc_list);
 382         kfree(td_desc);
 383 }
 384
 385 static void td_desc_put(struct timb_dma_chan *td_chan,
 386         struct timb_dma_desc *td_desc)
 387 {
 388         dev_dbg(chan2dev(&td_chan->chan), "Putting desc: %p\n", td_desc);
 389
 390         spin_lock_bh(&td_chan->lock);
 391         list_add(&td_desc->desc_node, &td_chan->free_list);
 392         spin_unlock_bh(&td_chan->lock);
 393 }
 394
 395 static struct timb_dma_desc *td_desc_get(struct timb_dma_chan *td_chan)
 396 {
 397         struct timb_dma_desc *td_desc, *_td_desc;
 398         struct timb_dma_desc *ret = NULL;
 399
 400         spin_lock_bh(&td_chan->lock);
 401         list_for_each_entry_safe(td_desc, _td_desc, &td_chan->free_list,
 402                 desc_node) {
 403                 if (async_tx_test_ack(&td_desc->txd)) {
 404                         list_del(&td_desc->desc_node);
 405                         ret = td_desc;
 406                         break;
 407                 }
 408                 dev_dbg(chan2dev(&td_chan->chan), "desc %p not ACKed\n",
 409                         td_desc);
 410         }
 411         spin_unlock_bh(&td_chan->lock);
 412
 413         return ret;
 414 }
 415
 416 static int td_alloc_chan_resources(struct dma_chan *chan)
 417 {
 418         struct timb_dma_chan *td_chan =
 419                 container_of(chan, struct timb_dma_chan, chan);
 420         int i;
 421
 422         dev_dbg(chan2dev(chan), "%s: entry\n", __func__);
 423
 424         BUG_ON(!list_empty(&td_chan->free_list));
 425         for (i = 0; i < td_chan->descs; i++) {
 426                 struct timb_dma_desc *td_desc = td_alloc_init_desc(td_chan);
 427                 if (!td_desc) {
 428                         if (i)
 429                                 break;
 430                         else {
 431                                 dev_err(chan2dev(chan),
 432                                         "Couldnt allocate any descriptors\n");
 433                                 return -ENOMEM;
 434                         }
 435                 }
 436
 437                 td_desc_put(td_chan, td_desc);
 438         }
 439
 440         spin_lock_bh(&td_chan->lock);
 441         dma_cookie_init(chan);
 442         spin_unlock_bh(&td_chan->lock);
 443
 444         return 0;
 445 }
 446
 447 static void td_free_chan_resources(struct dma_chan *chan)
 448 {
 449         struct timb_dma_chan *td_chan =
 450                 container_of(chan, struct timb_dma_chan, chan);
 451         struct timb_dma_desc *td_desc, *_td_desc;
 452         LIST_HEAD(list);
 453
 454         dev_dbg(chan2dev(chan), "%s: Entry\n", __func__);
 455
 456         /* check that all descriptors are free */
 457         BUG_ON(!list_empty(&td_chan->active_list));
 458         BUG_ON(!list_empty(&td_chan->queue));
 459
 460         spin_lock_bh(&td_chan->lock);
 461         list_splice_init(&td_chan->free_list, &list);
 462         spin_unlock_bh(&td_chan->lock);
 463
 464         list_for_each_entry_safe(td_desc, _td_desc, &list, desc_node) {
 465                 dev_dbg(chan2dev(chan), "%s: Freeing desc: %p\n", __func__,
 466                         td_desc);
 467                 td_free_desc(td_desc);
 468         }
 469 }
 470
 471 static enum dma_status td_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
 472                                     struct dma_tx_state *txstate)
 473 {
 474         enum dma_status ret;
 475
 476         dev_dbg(chan2dev(chan), "%s: Entry\n", __func__);
 477
 478         ret = dma_cookie_status(chan, cookie, txstate);
 479
 480         dev_dbg(chan2dev(chan), "%s: exit, ret: %d\n",  __func__, ret);
 481
 482         return ret;
 483 }
 484
 485 static void td_issue_pending(struct dma_chan *chan)
 486 {
 487         struct timb_dma_chan *td_chan =
 488                 container_of(chan, struct timb_dma_chan, chan);
 489
 490         dev_dbg(chan2dev(chan), "%s: Entry\n", __func__);
 491         spin_lock_bh(&td_chan->lock);
 492
 493         if (!list_empty(&td_chan->active_list))
 494                 /* transfer ongoing */
 495                 if (__td_dma_done_ack(td_chan))
 496                         __td_finish(td_chan);
 497
 498         if (list_empty(&td_chan->active_list) && !list_empty(&td_chan->queue))
 499                 __td_start_next(td_chan);
 500
 501         spin_unlock_bh(&td_chan->lock);
 502 }
 503
 504 static struct dma_async_tx_descriptor *td_prep_slave_sg(struct dma_chan *chan,
 505         struct scatterlist *sgl, unsigned int sg_len,
 506         enum dma_transfer_direction direction, unsigned long flags,
 507         void *context)
 508 {
 509         struct timb_dma_chan *td_chan =
 510                 container_of(chan, struct timb_dma_chan, chan);
 511         struct timb_dma_desc *td_desc;
 512         struct scatterlist *sg;
 513         unsigned int i;
 514         unsigned int desc_usage = 0;
 515
 516         if (!sgl || !sg_len) {
 517                 dev_err(chan2dev(chan), "%s: No SG list\n", __func__);
 518                 return NULL;
 519         }
 520
 521         /* even channels are for RX, odd for TX */
 522         if (td_chan->direction != direction) {
 523                 dev_err(chan2dev(chan),
 524                         "Requesting channel in wrong direction\n");
 525                 return NULL;
 526         }
 527
 528         td_desc = td_desc_get(td_chan);
 529         if (!td_desc) {
 530                 dev_err(chan2dev(chan), "Not enough descriptors available\n");
 531                 return NULL;
 532         }
 533
 534         td_desc->interrupt = (flags & DMA_PREP_INTERRUPT) != 0;
 535
 536         for_each_sg(sgl, sg, sg_len, i) {
 537                 int err;
 538                 if (desc_usage > td_desc->desc_list_len) {
 539                         dev_err(chan2dev(chan), "No descriptor space\n");
 540                         return NULL;
 541                 }
 542
 543                 err = td_fill_desc(td_chan, td_desc->desc_list + desc_usage, sg,
 544                         i == (sg_len - 1));
 545                 if (err) {
 546                         dev_err(chan2dev(chan), "Failed to update desc: %d\n",
 547                                 err);
 548                         td_desc_put(td_chan, td_desc);
 549                         return NULL;
 550                 }
 551                 desc_usage += TIMB_DMA_DESC_SIZE;
 552         }
 553
 554         dma_sync_single_for_device(chan2dmadev(chan), td_desc->txd.phys,
 555                 td_desc->desc_list_len, DMA_MEM_TO_DEV);
 556
 557         return &td_desc->txd;
 558 }
 559
 560 static int td_terminate_all(struct dma_chan *chan)
 561 {
 562         struct timb_dma_chan *td_chan =
 563                 container_of(chan, struct timb_dma_chan, chan);
 564         struct timb_dma_desc *td_desc, *_td_desc;
 565
 566         dev_dbg(chan2dev(chan), "%s: Entry\n", __func__);
 567
 568         /* first the easy part, put the queue into the free list */
 569         spin_lock_bh(&td_chan->lock);
 570         list_for_each_entry_safe(td_desc, _td_desc, &td_chan->queue,
 571                 desc_node)
 572                 list_move(&td_desc->desc_node, &td_chan->free_list);
 573
 574         /* now tear down the running */
 575         __td_finish(td_chan);
 576         spin_unlock_bh(&td_chan->lock);
 577
 578         return 0;
 579 }
 580
 581 static void td_tasklet(unsigned long data)
 582 {
 583         struct timb_dma *td = (struct timb_dma *)data;
 584         u32 isr;
 585         u32 ipr;
 586         u32 ier;
 587         int i;
 588
 589         isr = ioread32(td->membase + TIMBDMA_ISR);
 590         ipr = isr & __td_ier_mask(td);
 591
 592         /* ack the interrupts */
 593         iowrite32(ipr, td->membase + TIMBDMA_ISR);
 594
 595         for (i = 0; i < td->dma.chancnt; i++)
 596                 if (ipr & (1 << i)) {
 597                         struct timb_dma_chan *td_chan = td->channels + i;
 598                         spin_lock(&td_chan->lock);
 599                         __td_finish(td_chan);
 600                         if (!list_empty(&td_chan->queue))
 601                                 __td_start_next(td_chan);
 602                         spin_unlock(&td_chan->lock);
 603                 }
 604
 605         ier = __td_ier_mask(td);
 606         iowrite32(ier, td->membase + TIMBDMA_IER);
 607 }
 608
 609
 610 static irqreturn_t td_irq(int irq, void *devid)
 611 {
 612         struct timb_dma *td = devid;
 613         u32 ipr = ioread32(td->membase + TIMBDMA_IPR);
 614
 615         if (ipr) {
 616                 /* disable interrupts, will be re-enabled in tasklet */
 617                 iowrite32(0, td->membase + TIMBDMA_IER);
 618
 619                 tasklet_schedule(&td->tasklet);
 620
 621                 return IRQ_HANDLED;
 622         } else
 623                 return IRQ_NONE;
 624 }
 625
 626
 627 static int td_probe(struct platform_device *pdev)
 628 {
 629         struct timb_dma_platform_data *pdata = dev_get_platdata(&pdev->dev);
 630         struct timb_dma *td;
 631         struct resource *iomem;
 632         int irq;
 633         int err;
 634         int i;
 635
 636         if (!pdata) {
 637                 dev_err(&pdev->dev, "No platform data\n");
 638                 return -EINVAL;
 639         }
 640
 641         iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 642         if (!iomem)
 643                 return -EINVAL;
 644
 645         irq = platform_get_irq(pdev, 0);
 646         if (irq < 0)
 647                 return irq;
 648
 649         if (!request_mem_region(iomem->start, resource_size(iomem),
 650                 DRIVER_NAME))
 651                 return -EBUSY;
 652
 653         td  = kzalloc(sizeof(struct timb_dma) +
 654                 sizeof(struct timb_dma_chan) * pdata->nr_channels, GFP_KERNEL);
 655         if (!td) {
 656                 err = -ENOMEM;
 657                 goto err_release_region;
 658         }
 659
 660         dev_dbg(&pdev->dev, "Allocated TD: %p\n", td);
 661
 662         td->membase = ioremap(iomem->start, resource_size(iomem));
 663         if (!td->membase) {
 664                 dev_err(&pdev->dev, "Failed to remap I/O memory\n");
 665                 err = -ENOMEM;
 666                 goto err_free_mem;
 667         }
 668
 669         /* 32bit addressing */
 670         iowrite32(TIMBDMA_32BIT_ADDR, td->membase + TIMBDMA_ACR);
 671
 672         /* disable and clear any interrupts */
 673         iowrite32(0x0, td->membase + TIMBDMA_IER);
 674         iowrite32(0xFFFFFFFF, td->membase + TIMBDMA_ISR);
 675
 676         tasklet_init(&td->tasklet, td_tasklet, (unsigned long)td);
 677
 678         err = request_irq(irq, td_irq, IRQF_SHARED, DRIVER_NAME, td);
 679         if (err) {
 680                 dev_err(&pdev->dev, "Failed to request IRQ\n");
 681                 goto err_tasklet_kill;
 682         }
 683
 684         td->dma.device_alloc_chan_resources     = td_alloc_chan_resources;
 685         td->dma.device_free_chan_resources      = td_free_chan_resources;
 686         td->dma.device_tx_status                = td_tx_status;
 687         td->dma.device_issue_pending            = td_issue_pending;
 688
 689         dma_cap_set(DMA_SLAVE, td->dma.cap_mask);
 690         dma_cap_set(DMA_PRIVATE, td->dma.cap_mask);
 691         td->dma.device_prep_slave_sg = td_prep_slave_sg;
 692         td->dma.device_terminate_all = td_terminate_all;
 693
 694         td->dma.dev = &pdev->dev;
 695
 696         INIT_LIST_HEAD(&td->dma.channels);
 697
 698         for (i = 0; i < pdata->nr_channels; i++) {
 699                 struct timb_dma_chan *td_chan = &td->channels[i];
 700                 struct timb_dma_platform_data_channel *pchan =
 701                         pdata->channels + i;
 702
 703                 /* even channels are RX, odd are TX */
 704                 if ((i % 2) == pchan->rx) {
 705                         dev_err(&pdev->dev, "Wrong channel configuration\n");
 706                         err = -EINVAL;
 707                         goto err_free_irq;
 708                 }
 709
 710                 td_chan->chan.device = &td->dma;
 711                 dma_cookie_init(&td_chan->chan);
 712                 spin_lock_init(&td_chan->lock);
 713                 INIT_LIST_HEAD(&td_chan->active_list);
 714                 INIT_LIST_HEAD(&td_chan->queue);
 715                 INIT_LIST_HEAD(&td_chan->free_list);
 716
 717                 td_chan->descs = pchan->descriptors;
 718                 td_chan->desc_elems = pchan->descriptor_elements;
 719                 td_chan->bytes_per_line = pchan->bytes_per_line;
 720                 td_chan->direction = pchan->rx ? DMA_DEV_TO_MEM :
 721                         DMA_MEM_TO_DEV;
 722
 723                 td_chan->membase = td->membase +
 724                         (i / 2) * TIMBDMA_INSTANCE_OFFSET +
 725                         (pchan->rx ? 0 : TIMBDMA_INSTANCE_TX_OFFSET);
 726
 727                 dev_dbg(&pdev->dev, "Chan: %d, membase: %p\n",
 728                         i, td_chan->membase);
 729
 730                 list_add_tail(&td_chan->chan.device_node, &td->dma.channels);
 731         }
 732
 733         err = dma_async_device_register(&td->dma);
 734         if (err) {
 735                 dev_err(&pdev->dev, "Failed to register async device\n");
 736                 goto err_free_irq;
 737         }
 738
 739         platform_set_drvdata(pdev, td);
 740
 741         dev_dbg(&pdev->dev, "Probe result: %d\n", err);
 742         return err;
 743
 744 err_free_irq:
 745         free_irq(irq, td);
 746 err_tasklet_kill:
 747         tasklet_kill(&td->tasklet);
 748         iounmap(td->membase);
 749 err_free_mem:
 750         kfree(td);
 751 err_release_region:
 752         release_mem_region(iomem->start, resource_size(iomem));
 753
 754         return err;
 755
 756 }
 757
 758 static int td_remove(struct platform_device *pdev)
 759 {
 760         struct timb_dma *td = platform_get_drvdata(pdev);
 761         struct resource *iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 762         int irq = platform_get_irq(pdev, 0);
 763
 764         dma_async_device_unregister(&td->dma);
 765         free_irq(irq, td);
 766         tasklet_kill(&td->tasklet);
 767         iounmap(td->membase);
 768         kfree(td);
 769         release_mem_region(iomem->start, resource_size(iomem));
 770
 771         dev_dbg(&pdev->dev, "Removed...\n");
 772         return 0;
 773 }
 774
 775 static struct platform_driver td_driver = {
 776         .driver = {
 777                 .name   = DRIVER_NAME,
 778         },
 779         .probe  = td_probe,
 780         .remove = td_remove,
 781 };
 782
 783 module_platform_driver(td_driver);
 784
 785 MODULE_LICENSE("GPL v2");
 786 MODULE_DESCRIPTION("Timberdale DMA controller driver");
 787 MODULE_AUTHOR("Pelagicore AB <info@pelagicore.com>");
 788 MODULE_ALIAS("platform:"DRIVER_NAME);