drivers/dma/dma-jz4740.c

   1 /*
   2  *  Copyright (C) 2013, Lars-Peter Clausen <lars@metafoo.de>
   3  *  JZ4740 DMAC support
   4  *
   5  *  This program is free software; you can redistribute it and/or modify it
   6  *  under  the terms of the GNU General  Public License as published by the
   7  *  Free Software Foundation;  either version 2 of the License, or (at your
   8  *  option) any later version.
   9  *
  10  */
  11
  12 #include <linux/dmaengine.h>
  13 #include <linux/dma-mapping.h>
  14 #include <linux/err.h>
  15 #include <linux/init.h>
  16 #include <linux/list.h>
  17 #include <linux/module.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/slab.h>
  20 #include <linux/spinlock.h>
  21 #include <linux/irq.h>
  22 #include <linux/clk.h>
  23
  24 #include <asm/mach-jz4740/dma.h>
  25
  26 #include "virt-dma.h"
  27
  28 #define JZ_DMA_NR_CHANS 6
  29
  30 #define JZ_REG_DMA_SRC_ADDR(x)          (0x00 + (x) * 0x20)
  31 #define JZ_REG_DMA_DST_ADDR(x)          (0x04 + (x) * 0x20)
  32 #define JZ_REG_DMA_TRANSFER_COUNT(x)    (0x08 + (x) * 0x20)
  33 #define JZ_REG_DMA_REQ_TYPE(x)          (0x0C + (x) * 0x20)
  34 #define JZ_REG_DMA_STATUS_CTRL(x)       (0x10 + (x) * 0x20)
  35 #define JZ_REG_DMA_CMD(x)               (0x14 + (x) * 0x20)
  36 #define JZ_REG_DMA_DESC_ADDR(x)         (0x18 + (x) * 0x20)
  37
  38 #define JZ_REG_DMA_CTRL                 0x300
  39 #define JZ_REG_DMA_IRQ                  0x304
  40 #define JZ_REG_DMA_DOORBELL             0x308
  41 #define JZ_REG_DMA_DOORBELL_SET         0x30C
  42
  43 #define JZ_DMA_STATUS_CTRL_NO_DESC              BIT(31)
  44 #define JZ_DMA_STATUS_CTRL_DESC_INV             BIT(6)
  45 #define JZ_DMA_STATUS_CTRL_ADDR_ERR             BIT(4)
  46 #define JZ_DMA_STATUS_CTRL_TRANSFER_DONE        BIT(3)
  47 #define JZ_DMA_STATUS_CTRL_HALT                 BIT(2)
  48 #define JZ_DMA_STATUS_CTRL_COUNT_TERMINATE      BIT(1)
  49 #define JZ_DMA_STATUS_CTRL_ENABLE               BIT(0)
  50
  51 #define JZ_DMA_CMD_SRC_INC                      BIT(23)
  52 #define JZ_DMA_CMD_DST_INC                      BIT(22)
  53 #define JZ_DMA_CMD_RDIL_MASK                    (0xf << 16)
  54 #define JZ_DMA_CMD_SRC_WIDTH_MASK               (0x3 << 14)
  55 #define JZ_DMA_CMD_DST_WIDTH_MASK               (0x3 << 12)
  56 #define JZ_DMA_CMD_INTERVAL_LENGTH_MASK         (0x7 << 8)
  57 #define JZ_DMA_CMD_BLOCK_MODE                   BIT(7)
  58 #define JZ_DMA_CMD_DESC_VALID                   BIT(4)
  59 #define JZ_DMA_CMD_DESC_VALID_MODE              BIT(3)
  60 #define JZ_DMA_CMD_VALID_IRQ_ENABLE             BIT(2)
  61 #define JZ_DMA_CMD_TRANSFER_IRQ_ENABLE          BIT(1)
  62 #define JZ_DMA_CMD_LINK_ENABLE                  BIT(0)
  63
  64 #define JZ_DMA_CMD_FLAGS_OFFSET 22
  65 #define JZ_DMA_CMD_RDIL_OFFSET 16
  66 #define JZ_DMA_CMD_SRC_WIDTH_OFFSET 14
  67 #define JZ_DMA_CMD_DST_WIDTH_OFFSET 12
  68 #define JZ_DMA_CMD_TRANSFER_SIZE_OFFSET 8
  69 #define JZ_DMA_CMD_MODE_OFFSET 7
  70
  71 #define JZ_DMA_CTRL_PRIORITY_MASK               (0x3 << 8)
  72 #define JZ_DMA_CTRL_HALT                        BIT(3)
  73 #define JZ_DMA_CTRL_ADDRESS_ERROR               BIT(2)
  74 #define JZ_DMA_CTRL_ENABLE                      BIT(0)
  75
  76 enum jz4740_dma_width {
  77         JZ4740_DMA_WIDTH_32BIT  = 0,
  78         JZ4740_DMA_WIDTH_8BIT   = 1,
  79         JZ4740_DMA_WIDTH_16BIT  = 2,
  80 };
  81
  82 enum jz4740_dma_transfer_size {
  83         JZ4740_DMA_TRANSFER_SIZE_4BYTE  = 0,
  84         JZ4740_DMA_TRANSFER_SIZE_1BYTE  = 1,
  85         JZ4740_DMA_TRANSFER_SIZE_2BYTE  = 2,
  86         JZ4740_DMA_TRANSFER_SIZE_16BYTE = 3,
  87         JZ4740_DMA_TRANSFER_SIZE_32BYTE = 4,
  88 };
  89
  90 enum jz4740_dma_flags {
  91         JZ4740_DMA_SRC_AUTOINC = 0x2,
  92         JZ4740_DMA_DST_AUTOINC = 0x1,
  93 };
  94
  95 enum jz4740_dma_mode {
  96         JZ4740_DMA_MODE_SINGLE  = 0,
  97         JZ4740_DMA_MODE_BLOCK   = 1,
  98 };
  99
 100 struct jz4740_dma_sg {
 101         dma_addr_t addr;
 102         unsigned int len;
 103 };
 104
 105 struct jz4740_dma_desc {
 106         struct virt_dma_desc vdesc;
 107
 108         enum dma_transfer_direction direction;
 109         bool cyclic;
 110
 111         unsigned int num_sgs;
 112         struct jz4740_dma_sg sg[];
 113 };
 114
 115 struct jz4740_dmaengine_chan {
 116         struct virt_dma_chan vchan;
 117         unsigned int id;
 118
 119         dma_addr_t fifo_addr;
 120         unsigned int transfer_shift;
 121
 122         struct jz4740_dma_desc *desc;
 123         unsigned int next_sg;
 124 };
 125
 126 struct jz4740_dma_dev {
 127         struct dma_device ddev;
 128         void __iomem *base;
 129         struct clk *clk;
 130
 131         struct jz4740_dmaengine_chan chan[JZ_DMA_NR_CHANS];
 132 };
 133
 134 static struct jz4740_dma_dev *jz4740_dma_chan_get_dev(
 135         struct jz4740_dmaengine_chan *chan)
 136 {
 137         return container_of(chan->vchan.chan.device, struct jz4740_dma_dev,
 138                 ddev);
 139 }
 140
 141 static struct jz4740_dmaengine_chan *to_jz4740_dma_chan(struct dma_chan *c)
 142 {
 143         return container_of(c, struct jz4740_dmaengine_chan, vchan.chan);
 144 }
 145
 146 static struct jz4740_dma_desc *to_jz4740_dma_desc(struct virt_dma_desc *vdesc)
 147 {
 148         return container_of(vdesc, struct jz4740_dma_desc, vdesc);
 149 }
 150
 151 static inline uint32_t jz4740_dma_read(struct jz4740_dma_dev *dmadev,
 152         unsigned int reg)
 153 {
 154         return readl(dmadev->base + reg);
 155 }
 156
 157 static inline void jz4740_dma_write(struct jz4740_dma_dev *dmadev,
 158         unsigned reg, uint32_t val)
 159 {
 160         writel(val, dmadev->base + reg);
 161 }
 162
 163 static inline void jz4740_dma_write_mask(struct jz4740_dma_dev *dmadev,
 164         unsigned int reg, uint32_t val, uint32_t mask)
 165 {
 166         uint32_t tmp;
 167
 168         tmp = jz4740_dma_read(dmadev, reg);
 169         tmp &= ~mask;
 170         tmp |= val;
 171         jz4740_dma_write(dmadev, reg, tmp);
 172 }
 173
 174 static struct jz4740_dma_desc *jz4740_dma_alloc_desc(unsigned int num_sgs)
 175 {
 176         return kzalloc(sizeof(struct jz4740_dma_desc) +
 177                 sizeof(struct jz4740_dma_sg) * num_sgs, GFP_ATOMIC);
 178 }
 179
 180 static enum jz4740_dma_width jz4740_dma_width(enum dma_slave_buswidth width)
 181 {
 182         switch (width) {
 183         case DMA_SLAVE_BUSWIDTH_1_BYTE:
 184                 return JZ4740_DMA_WIDTH_8BIT;
 185         case DMA_SLAVE_BUSWIDTH_2_BYTES:
 186                 return JZ4740_DMA_WIDTH_16BIT;
 187         case DMA_SLAVE_BUSWIDTH_4_BYTES:
 188                 return JZ4740_DMA_WIDTH_32BIT;
 189         default:
 190                 return JZ4740_DMA_WIDTH_32BIT;
 191         }
 192 }
 193
 194 static enum jz4740_dma_transfer_size jz4740_dma_maxburst(u32 maxburst)
 195 {
 196         if (maxburst <= 1)
 197                 return JZ4740_DMA_TRANSFER_SIZE_1BYTE;
 198         else if (maxburst <= 3)
 199                 return JZ4740_DMA_TRANSFER_SIZE_2BYTE;
 200         else if (maxburst <= 15)
 201                 return JZ4740_DMA_TRANSFER_SIZE_4BYTE;
 202         else if (maxburst <= 31)
 203                 return JZ4740_DMA_TRANSFER_SIZE_16BYTE;
 204
 205         return JZ4740_DMA_TRANSFER_SIZE_32BYTE;
 206 }
 207
 208 static int jz4740_dma_slave_config(struct dma_chan *c,
 209                                    struct dma_slave_config *config)
 210 {
 211         struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
 212         struct jz4740_dma_dev *dmadev = jz4740_dma_chan_get_dev(chan);
 213         enum jz4740_dma_width src_width;
 214         enum jz4740_dma_width dst_width;
 215         enum jz4740_dma_transfer_size transfer_size;
 216         enum jz4740_dma_flags flags;
 217         uint32_t cmd;
 218
 219         switch (config->direction) {
 220         case DMA_MEM_TO_DEV:
 221                 flags = JZ4740_DMA_SRC_AUTOINC;
 222                 transfer_size = jz4740_dma_maxburst(config->dst_maxburst);
 223                 chan->fifo_addr = config->dst_addr;
 224                 break;
 225         case DMA_DEV_TO_MEM:
 226                 flags = JZ4740_DMA_DST_AUTOINC;
 227                 transfer_size = jz4740_dma_maxburst(config->src_maxburst);
 228                 chan->fifo_addr = config->src_addr;
 229                 break;
 230         default:
 231                 return -EINVAL;
 232         }
 233
 234         src_width = jz4740_dma_width(config->src_addr_width);
 235         dst_width = jz4740_dma_width(config->dst_addr_width);
 236
 237         switch (transfer_size) {
 238         case JZ4740_DMA_TRANSFER_SIZE_2BYTE:
 239                 chan->transfer_shift = 1;
 240                 break;
 241         case JZ4740_DMA_TRANSFER_SIZE_4BYTE:
 242                 chan->transfer_shift = 2;
 243                 break;
 244         case JZ4740_DMA_TRANSFER_SIZE_16BYTE:
 245                 chan->transfer_shift = 4;
 246                 break;
 247         case JZ4740_DMA_TRANSFER_SIZE_32BYTE:
 248                 chan->transfer_shift = 5;
 249                 break;
 250         default:
 251                 chan->transfer_shift = 0;
 252                 break;
 253         }
 254
 255         cmd = flags << JZ_DMA_CMD_FLAGS_OFFSET;
 256         cmd |= src_width << JZ_DMA_CMD_SRC_WIDTH_OFFSET;
 257         cmd |= dst_width << JZ_DMA_CMD_DST_WIDTH_OFFSET;
 258         cmd |= transfer_size << JZ_DMA_CMD_TRANSFER_SIZE_OFFSET;
 259         cmd |= JZ4740_DMA_MODE_SINGLE << JZ_DMA_CMD_MODE_OFFSET;
 260         cmd |= JZ_DMA_CMD_TRANSFER_IRQ_ENABLE;
 261
 262         jz4740_dma_write(dmadev, JZ_REG_DMA_CMD(chan->id), cmd);
 263         jz4740_dma_write(dmadev, JZ_REG_DMA_STATUS_CTRL(chan->id), 0);
 264         jz4740_dma_write(dmadev, JZ_REG_DMA_REQ_TYPE(chan->id),
 265                 config->slave_id);
 266
 267         return 0;
 268 }
 269
 270 static int jz4740_dma_terminate_all(struct dma_chan *c)
 271 {
 272         struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
 273         struct jz4740_dma_dev *dmadev = jz4740_dma_chan_get_dev(chan);
 274         unsigned long flags;
 275         LIST_HEAD(head);
 276
 277         spin_lock_irqsave(&chan->vchan.lock, flags);
 278         jz4740_dma_write_mask(dmadev, JZ_REG_DMA_STATUS_CTRL(chan->id), 0,
 279                         JZ_DMA_STATUS_CTRL_ENABLE);
 280         chan->desc = NULL;
 281         vchan_get_all_descriptors(&chan->vchan, &head);
 282         spin_unlock_irqrestore(&chan->vchan.lock, flags);
 283
 284         vchan_dma_desc_free_list(&chan->vchan, &head);
 285
 286         return 0;
 287 }
 288
 289 static int jz4740_dma_start_transfer(struct jz4740_dmaengine_chan *chan)
 290 {
 291         struct jz4740_dma_dev *dmadev = jz4740_dma_chan_get_dev(chan);
 292         dma_addr_t src_addr, dst_addr;
 293         struct virt_dma_desc *vdesc;
 294         struct jz4740_dma_sg *sg;
 295
 296         jz4740_dma_write_mask(dmadev, JZ_REG_DMA_STATUS_CTRL(chan->id), 0,
 297                         JZ_DMA_STATUS_CTRL_ENABLE);
 298
 299         if (!chan->desc) {
 300                 vdesc = vchan_next_desc(&chan->vchan);
 301                 if (!vdesc)
 302                         return 0;
 303                 chan->desc = to_jz4740_dma_desc(vdesc);
 304                 chan->next_sg = 0;
 305         }
 306
 307         if (chan->next_sg == chan->desc->num_sgs)
 308                 chan->next_sg = 0;
 309
 310         sg = &chan->desc->sg[chan->next_sg];
 311
 312         if (chan->desc->direction == DMA_MEM_TO_DEV) {
 313                 src_addr = sg->addr;
 314                 dst_addr = chan->fifo_addr;
 315         } else {
 316                 src_addr = chan->fifo_addr;
 317                 dst_addr = sg->addr;
 318         }
 319         jz4740_dma_write(dmadev, JZ_REG_DMA_SRC_ADDR(chan->id), src_addr);
 320         jz4740_dma_write(dmadev, JZ_REG_DMA_DST_ADDR(chan->id), dst_addr);
 321         jz4740_dma_write(dmadev, JZ_REG_DMA_TRANSFER_COUNT(chan->id),
 322                         sg->len >> chan->transfer_shift);
 323
 324         chan->next_sg++;
 325
 326         jz4740_dma_write_mask(dmadev, JZ_REG_DMA_STATUS_CTRL(chan->id),
 327                         JZ_DMA_STATUS_CTRL_NO_DESC | JZ_DMA_STATUS_CTRL_ENABLE,
 328                         JZ_DMA_STATUS_CTRL_HALT | JZ_DMA_STATUS_CTRL_NO_DESC |
 329                         JZ_DMA_STATUS_CTRL_ENABLE);
 330
 331         jz4740_dma_write_mask(dmadev, JZ_REG_DMA_CTRL,
 332                         JZ_DMA_CTRL_ENABLE,
 333                         JZ_DMA_CTRL_HALT | JZ_DMA_CTRL_ENABLE);
 334
 335         return 0;
 336 }
 337
 338 static void jz4740_dma_chan_irq(struct jz4740_dmaengine_chan *chan)
 339 {
 340         spin_lock(&chan->vchan.lock);
 341         if (chan->desc) {
 342                 if (chan->desc->cyclic) {
 343                         vchan_cyclic_callback(&chan->desc->vdesc);
 344                 } else {
 345                         if (chan->next_sg == chan->desc->num_sgs) {
 346                                 list_del(&chan->desc->vdesc.node);
 347                                 vchan_cookie_complete(&chan->desc->vdesc);
 348                                 chan->desc = NULL;
 349                         }
 350                 }
 351         }
 352         jz4740_dma_start_transfer(chan);
 353         spin_unlock(&chan->vchan.lock);
 354 }
 355
 356 static irqreturn_t jz4740_dma_irq(int irq, void *devid)
 357 {
 358         struct jz4740_dma_dev *dmadev = devid;
 359         uint32_t irq_status;
 360         unsigned int i;
 361
 362         irq_status = readl(dmadev->base + JZ_REG_DMA_IRQ);
 363
 364         for (i = 0; i < 6; ++i) {
 365                 if (irq_status & (1 << i)) {
 366                         jz4740_dma_write_mask(dmadev,
 367                                 JZ_REG_DMA_STATUS_CTRL(i), 0,
 368                                 JZ_DMA_STATUS_CTRL_ENABLE |
 369                                 JZ_DMA_STATUS_CTRL_TRANSFER_DONE);
 370
 371                         jz4740_dma_chan_irq(&dmadev->chan[i]);
 372                 }
 373         }
 374
 375         return IRQ_HANDLED;
 376 }
 377
 378 static void jz4740_dma_issue_pending(struct dma_chan *c)
 379 {
 380         struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
 381         unsigned long flags;
 382
 383         spin_lock_irqsave(&chan->vchan.lock, flags);
 384         if (vchan_issue_pending(&chan->vchan) && !chan->desc)
 385                 jz4740_dma_start_transfer(chan);
 386         spin_unlock_irqrestore(&chan->vchan.lock, flags);
 387 }
 388
 389 static struct dma_async_tx_descriptor *jz4740_dma_prep_slave_sg(
 390         struct dma_chan *c, struct scatterlist *sgl,
 391         unsigned int sg_len, enum dma_transfer_direction direction,
 392         unsigned long flags, void *context)
 393 {
 394         struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
 395         struct jz4740_dma_desc *desc;
 396         struct scatterlist *sg;
 397         unsigned int i;
 398
 399         desc = jz4740_dma_alloc_desc(sg_len);
 400         if (!desc)
 401                 return NULL;
 402
 403         for_each_sg(sgl, sg, sg_len, i) {
 404                 desc->sg[i].addr = sg_dma_address(sg);
 405                 desc->sg[i].len = sg_dma_len(sg);
 406         }
 407
 408         desc->num_sgs = sg_len;
 409         desc->direction = direction;
 410         desc->cyclic = false;
 411
 412         return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
 413 }
 414
 415 static struct dma_async_tx_descriptor *jz4740_dma_prep_dma_cyclic(
 416         struct dma_chan *c, dma_addr_t buf_addr, size_t buf_len,
 417         size_t period_len, enum dma_transfer_direction direction,
 418         unsigned long flags)
 419 {
 420         struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
 421         struct jz4740_dma_desc *desc;
 422         unsigned int num_periods, i;
 423
 424         if (buf_len % period_len)
 425                 return NULL;
 426
 427         num_periods = buf_len / period_len;
 428
 429         desc = jz4740_dma_alloc_desc(num_periods);
 430         if (!desc)
 431                 return NULL;
 432
 433         for (i = 0; i < num_periods; i++) {
 434                 desc->sg[i].addr = buf_addr;
 435                 desc->sg[i].len = period_len;
 436                 buf_addr += period_len;
 437         }
 438
 439         desc->num_sgs = num_periods;
 440         desc->direction = direction;
 441         desc->cyclic = true;
 442
 443         return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
 444 }
 445
 446 static size_t jz4740_dma_desc_residue(struct jz4740_dmaengine_chan *chan,
 447         struct jz4740_dma_desc *desc, unsigned int next_sg)
 448 {
 449         struct jz4740_dma_dev *dmadev = jz4740_dma_chan_get_dev(chan);
 450         unsigned int residue, count;
 451         unsigned int i;
 452
 453         residue = 0;
 454
 455         for (i = next_sg; i < desc->num_sgs; i++)
 456                 residue += desc->sg[i].len;
 457
 458         if (next_sg != 0) {
 459                 count = jz4740_dma_read(dmadev,
 460                         JZ_REG_DMA_TRANSFER_COUNT(chan->id));
 461                 residue += count << chan->transfer_shift;
 462         }
 463
 464         return residue;
 465 }
 466
 467 static enum dma_status jz4740_dma_tx_status(struct dma_chan *c,
 468         dma_cookie_t cookie, struct dma_tx_state *state)
 469 {
 470         struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
 471         struct virt_dma_desc *vdesc;
 472         enum dma_status status;
 473         unsigned long flags;
 474
 475         status = dma_cookie_status(c, cookie, state);
 476         if (status == DMA_COMPLETE || !state)
 477                 return status;
 478
 479         spin_lock_irqsave(&chan->vchan.lock, flags);
 480         vdesc = vchan_find_desc(&chan->vchan, cookie);
 481         if (cookie == chan->desc->vdesc.tx.cookie) {
 482                 state->residue = jz4740_dma_desc_residue(chan, chan->desc,
 483                                 chan->next_sg);
 484         } else if (vdesc) {
 485                 state->residue = jz4740_dma_desc_residue(chan,
 486                                 to_jz4740_dma_desc(vdesc), 0);
 487         } else {
 488                 state->residue = 0;
 489         }
 490         spin_unlock_irqrestore(&chan->vchan.lock, flags);
 491
 492         return status;
 493 }
 494
 495 static void jz4740_dma_free_chan_resources(struct dma_chan *c)
 496 {
 497         vchan_free_chan_resources(to_virt_chan(c));
 498 }
 499
 500 static void jz4740_dma_desc_free(struct virt_dma_desc *vdesc)
 501 {
 502         kfree(container_of(vdesc, struct jz4740_dma_desc, vdesc));
 503 }
 504
 505 #define JZ4740_DMA_BUSWIDTHS (BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | \
 506         BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | BIT(DMA_SLAVE_BUSWIDTH_4_BYTES))
 507
 508 static int jz4740_dma_probe(struct platform_device *pdev)
 509 {
 510         struct jz4740_dmaengine_chan *chan;
 511         struct jz4740_dma_dev *dmadev;
 512         struct dma_device *dd;
 513         unsigned int i;
 514         struct resource *res;
 515         int ret;
 516         int irq;
 517
 518         dmadev = devm_kzalloc(&pdev->dev, sizeof(*dmadev), GFP_KERNEL);
 519         if (!dmadev)
 520                 return -EINVAL;
 521
 522         dd = &dmadev->ddev;
 523
 524         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 525         dmadev->base = devm_ioremap_resource(&pdev->dev, res);
 526         if (IS_ERR(dmadev->base))
 527                 return PTR_ERR(dmadev->base);
 528
 529         dmadev->clk = clk_get(&pdev->dev, "dma");
 530         if (IS_ERR(dmadev->clk))
 531                 return PTR_ERR(dmadev->clk);
 532
 533         clk_prepare_enable(dmadev->clk);
 534
 535         dma_cap_set(DMA_SLAVE, dd->cap_mask);
 536         dma_cap_set(DMA_CYCLIC, dd->cap_mask);
 537         dd->device_free_chan_resources = jz4740_dma_free_chan_resources;
 538         dd->device_tx_status = jz4740_dma_tx_status;
 539         dd->device_issue_pending = jz4740_dma_issue_pending;
 540         dd->device_prep_slave_sg = jz4740_dma_prep_slave_sg;
 541         dd->device_prep_dma_cyclic = jz4740_dma_prep_dma_cyclic;
 542         dd->device_config = jz4740_dma_slave_config;
 543         dd->device_terminate_all = jz4740_dma_terminate_all;
 544         dd->src_addr_widths = JZ4740_DMA_BUSWIDTHS;
 545         dd->dst_addr_widths = JZ4740_DMA_BUSWIDTHS;
 546         dd->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
 547         dd->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
 548         dd->dev = &pdev->dev;
 549         INIT_LIST_HEAD(&dd->channels);
 550
 551         for (i = 0; i < JZ_DMA_NR_CHANS; i++) {
 552                 chan = &dmadev->chan[i];
 553                 chan->id = i;
 554                 chan->vchan.desc_free = jz4740_dma_desc_free;
 555                 vchan_init(&chan->vchan, dd);
 556         }
 557
 558         ret = dma_async_device_register(dd);
 559         if (ret)
 560                 return ret;
 561
 562         irq = platform_get_irq(pdev, 0);
 563         ret = request_irq(irq, jz4740_dma_irq, 0, dev_name(&pdev->dev), dmadev);
 564         if (ret)
 565                 goto err_unregister;
 566
 567         platform_set_drvdata(pdev, dmadev);
 568
 569         return 0;
 570
 571 err_unregister:
 572         dma_async_device_unregister(dd);
 573         return ret;
 574 }
 575
 576 static int jz4740_dma_remove(struct platform_device *pdev)
 577 {
 578         struct jz4740_dma_dev *dmadev = platform_get_drvdata(pdev);
 579         int irq = platform_get_irq(pdev, 0);
 580
 581         free_irq(irq, dmadev);
 582         dma_async_device_unregister(&dmadev->ddev);
 583         clk_disable_unprepare(dmadev->clk);
 584
 585         return 0;
 586 }
 587
 588 static struct platform_driver jz4740_dma_driver = {
 589         .probe = jz4740_dma_probe,
 590         .remove = jz4740_dma_remove,
 591         .driver = {
 592                 .name = "jz4740-dma",
 593         },
 594 };
 595 module_platform_driver(jz4740_dma_driver);
 596
 597 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 598 MODULE_DESCRIPTION("JZ4740 DMA driver");
 599 MODULE_LICENSE("GPL v2");