linux/drivers/dma/dma-jz4740.c
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   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 "virt-dma.h"
  25
  26#define JZ_DMA_NR_CHANS 6
  27
  28#define JZ_REG_DMA_SRC_ADDR(x)          (0x00 + (x) * 0x20)
  29#define JZ_REG_DMA_DST_ADDR(x)          (0x04 + (x) * 0x20)
  30#define JZ_REG_DMA_TRANSFER_COUNT(x)    (0x08 + (x) * 0x20)
  31#define JZ_REG_DMA_REQ_TYPE(x)          (0x0C + (x) * 0x20)
  32#define JZ_REG_DMA_STATUS_CTRL(x)       (0x10 + (x) * 0x20)
  33#define JZ_REG_DMA_CMD(x)               (0x14 + (x) * 0x20)
  34#define JZ_REG_DMA_DESC_ADDR(x)         (0x18 + (x) * 0x20)
  35
  36#define JZ_REG_DMA_CTRL                 0x300
  37#define JZ_REG_DMA_IRQ                  0x304
  38#define JZ_REG_DMA_DOORBELL             0x308
  39#define JZ_REG_DMA_DOORBELL_SET         0x30C
  40
  41#define JZ_DMA_STATUS_CTRL_NO_DESC              BIT(31)
  42#define JZ_DMA_STATUS_CTRL_DESC_INV             BIT(6)
  43#define JZ_DMA_STATUS_CTRL_ADDR_ERR             BIT(4)
  44#define JZ_DMA_STATUS_CTRL_TRANSFER_DONE        BIT(3)
  45#define JZ_DMA_STATUS_CTRL_HALT                 BIT(2)
  46#define JZ_DMA_STATUS_CTRL_COUNT_TERMINATE      BIT(1)
  47#define JZ_DMA_STATUS_CTRL_ENABLE               BIT(0)
  48
  49#define JZ_DMA_CMD_SRC_INC                      BIT(23)
  50#define JZ_DMA_CMD_DST_INC                      BIT(22)
  51#define JZ_DMA_CMD_RDIL_MASK                    (0xf << 16)
  52#define JZ_DMA_CMD_SRC_WIDTH_MASK               (0x3 << 14)
  53#define JZ_DMA_CMD_DST_WIDTH_MASK               (0x3 << 12)
  54#define JZ_DMA_CMD_INTERVAL_LENGTH_MASK         (0x7 << 8)
  55#define JZ_DMA_CMD_BLOCK_MODE                   BIT(7)
  56#define JZ_DMA_CMD_DESC_VALID                   BIT(4)
  57#define JZ_DMA_CMD_DESC_VALID_MODE              BIT(3)
  58#define JZ_DMA_CMD_VALID_IRQ_ENABLE             BIT(2)
  59#define JZ_DMA_CMD_TRANSFER_IRQ_ENABLE          BIT(1)
  60#define JZ_DMA_CMD_LINK_ENABLE                  BIT(0)
  61
  62#define JZ_DMA_CMD_FLAGS_OFFSET 22
  63#define JZ_DMA_CMD_RDIL_OFFSET 16
  64#define JZ_DMA_CMD_SRC_WIDTH_OFFSET 14
  65#define JZ_DMA_CMD_DST_WIDTH_OFFSET 12
  66#define JZ_DMA_CMD_TRANSFER_SIZE_OFFSET 8
  67#define JZ_DMA_CMD_MODE_OFFSET 7
  68
  69#define JZ_DMA_CTRL_PRIORITY_MASK               (0x3 << 8)
  70#define JZ_DMA_CTRL_HALT                        BIT(3)
  71#define JZ_DMA_CTRL_ADDRESS_ERROR               BIT(2)
  72#define JZ_DMA_CTRL_ENABLE                      BIT(0)
  73
  74enum jz4740_dma_width {
  75        JZ4740_DMA_WIDTH_32BIT  = 0,
  76        JZ4740_DMA_WIDTH_8BIT   = 1,
  77        JZ4740_DMA_WIDTH_16BIT  = 2,
  78};
  79
  80enum jz4740_dma_transfer_size {
  81        JZ4740_DMA_TRANSFER_SIZE_4BYTE  = 0,
  82        JZ4740_DMA_TRANSFER_SIZE_1BYTE  = 1,
  83        JZ4740_DMA_TRANSFER_SIZE_2BYTE  = 2,
  84        JZ4740_DMA_TRANSFER_SIZE_16BYTE = 3,
  85        JZ4740_DMA_TRANSFER_SIZE_32BYTE = 4,
  86};
  87
  88enum jz4740_dma_flags {
  89        JZ4740_DMA_SRC_AUTOINC = 0x2,
  90        JZ4740_DMA_DST_AUTOINC = 0x1,
  91};
  92
  93enum jz4740_dma_mode {
  94        JZ4740_DMA_MODE_SINGLE  = 0,
  95        JZ4740_DMA_MODE_BLOCK   = 1,
  96};
  97
  98struct jz4740_dma_sg {
  99        dma_addr_t addr;
 100        unsigned int len;
 101};
 102
 103struct jz4740_dma_desc {
 104        struct virt_dma_desc vdesc;
 105
 106        enum dma_transfer_direction direction;
 107        bool cyclic;
 108
 109        unsigned int num_sgs;
 110        struct jz4740_dma_sg sg[];
 111};
 112
 113struct jz4740_dmaengine_chan {
 114        struct virt_dma_chan vchan;
 115        unsigned int id;
 116
 117        dma_addr_t fifo_addr;
 118        unsigned int transfer_shift;
 119
 120        struct jz4740_dma_desc *desc;
 121        unsigned int next_sg;
 122};
 123
 124struct jz4740_dma_dev {
 125        struct dma_device ddev;
 126        void __iomem *base;
 127        struct clk *clk;
 128
 129        struct jz4740_dmaengine_chan chan[JZ_DMA_NR_CHANS];
 130};
 131
 132static struct jz4740_dma_dev *jz4740_dma_chan_get_dev(
 133        struct jz4740_dmaengine_chan *chan)
 134{
 135        return container_of(chan->vchan.chan.device, struct jz4740_dma_dev,
 136                ddev);
 137}
 138
 139static struct jz4740_dmaengine_chan *to_jz4740_dma_chan(struct dma_chan *c)
 140{
 141        return container_of(c, struct jz4740_dmaengine_chan, vchan.chan);
 142}
 143
 144static struct jz4740_dma_desc *to_jz4740_dma_desc(struct virt_dma_desc *vdesc)
 145{
 146        return container_of(vdesc, struct jz4740_dma_desc, vdesc);
 147}
 148
 149static inline uint32_t jz4740_dma_read(struct jz4740_dma_dev *dmadev,
 150        unsigned int reg)
 151{
 152        return readl(dmadev->base + reg);
 153}
 154
 155static inline void jz4740_dma_write(struct jz4740_dma_dev *dmadev,
 156        unsigned reg, uint32_t val)
 157{
 158        writel(val, dmadev->base + reg);
 159}
 160
 161static inline void jz4740_dma_write_mask(struct jz4740_dma_dev *dmadev,
 162        unsigned int reg, uint32_t val, uint32_t mask)
 163{
 164        uint32_t tmp;
 165
 166        tmp = jz4740_dma_read(dmadev, reg);
 167        tmp &= ~mask;
 168        tmp |= val;
 169        jz4740_dma_write(dmadev, reg, tmp);
 170}
 171
 172static struct jz4740_dma_desc *jz4740_dma_alloc_desc(unsigned int num_sgs)
 173{
 174        return kzalloc(sizeof(struct jz4740_dma_desc) +
 175                sizeof(struct jz4740_dma_sg) * num_sgs, GFP_ATOMIC);
 176}
 177
 178static enum jz4740_dma_width jz4740_dma_width(enum dma_slave_buswidth width)
 179{
 180        switch (width) {
 181        case DMA_SLAVE_BUSWIDTH_1_BYTE:
 182                return JZ4740_DMA_WIDTH_8BIT;
 183        case DMA_SLAVE_BUSWIDTH_2_BYTES:
 184                return JZ4740_DMA_WIDTH_16BIT;
 185        case DMA_SLAVE_BUSWIDTH_4_BYTES:
 186                return JZ4740_DMA_WIDTH_32BIT;
 187        default:
 188                return JZ4740_DMA_WIDTH_32BIT;
 189        }
 190}
 191
 192static enum jz4740_dma_transfer_size jz4740_dma_maxburst(u32 maxburst)
 193{
 194        if (maxburst <= 1)
 195                return JZ4740_DMA_TRANSFER_SIZE_1BYTE;
 196        else if (maxburst <= 3)
 197                return JZ4740_DMA_TRANSFER_SIZE_2BYTE;
 198        else if (maxburst <= 15)
 199                return JZ4740_DMA_TRANSFER_SIZE_4BYTE;
 200        else if (maxburst <= 31)
 201                return JZ4740_DMA_TRANSFER_SIZE_16BYTE;
 202
 203        return JZ4740_DMA_TRANSFER_SIZE_32BYTE;
 204}
 205
 206static int jz4740_dma_slave_config(struct dma_chan *c,
 207                                   struct dma_slave_config *config)
 208{
 209        struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
 210        struct jz4740_dma_dev *dmadev = jz4740_dma_chan_get_dev(chan);
 211        enum jz4740_dma_width src_width;
 212        enum jz4740_dma_width dst_width;
 213        enum jz4740_dma_transfer_size transfer_size;
 214        enum jz4740_dma_flags flags;
 215        uint32_t cmd;
 216
 217        switch (config->direction) {
 218        case DMA_MEM_TO_DEV:
 219                flags = JZ4740_DMA_SRC_AUTOINC;
 220                transfer_size = jz4740_dma_maxburst(config->dst_maxburst);
 221                chan->fifo_addr = config->dst_addr;
 222                break;
 223        case DMA_DEV_TO_MEM:
 224                flags = JZ4740_DMA_DST_AUTOINC;
 225                transfer_size = jz4740_dma_maxburst(config->src_maxburst);
 226                chan->fifo_addr = config->src_addr;
 227                break;
 228        default:
 229                return -EINVAL;
 230        }
 231
 232        src_width = jz4740_dma_width(config->src_addr_width);
 233        dst_width = jz4740_dma_width(config->dst_addr_width);
 234
 235        switch (transfer_size) {
 236        case JZ4740_DMA_TRANSFER_SIZE_2BYTE:
 237                chan->transfer_shift = 1;
 238                break;
 239        case JZ4740_DMA_TRANSFER_SIZE_4BYTE:
 240                chan->transfer_shift = 2;
 241                break;
 242        case JZ4740_DMA_TRANSFER_SIZE_16BYTE:
 243                chan->transfer_shift = 4;
 244                break;
 245        case JZ4740_DMA_TRANSFER_SIZE_32BYTE:
 246                chan->transfer_shift = 5;
 247                break;
 248        default:
 249                chan->transfer_shift = 0;
 250                break;
 251        }
 252
 253        cmd = flags << JZ_DMA_CMD_FLAGS_OFFSET;
 254        cmd |= src_width << JZ_DMA_CMD_SRC_WIDTH_OFFSET;
 255        cmd |= dst_width << JZ_DMA_CMD_DST_WIDTH_OFFSET;
 256        cmd |= transfer_size << JZ_DMA_CMD_TRANSFER_SIZE_OFFSET;
 257        cmd |= JZ4740_DMA_MODE_SINGLE << JZ_DMA_CMD_MODE_OFFSET;
 258        cmd |= JZ_DMA_CMD_TRANSFER_IRQ_ENABLE;
 259
 260        jz4740_dma_write(dmadev, JZ_REG_DMA_CMD(chan->id), cmd);
 261        jz4740_dma_write(dmadev, JZ_REG_DMA_STATUS_CTRL(chan->id), 0);
 262        jz4740_dma_write(dmadev, JZ_REG_DMA_REQ_TYPE(chan->id),
 263                config->slave_id);
 264
 265        return 0;
 266}
 267
 268static int jz4740_dma_terminate_all(struct dma_chan *c)
 269{
 270        struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
 271        struct jz4740_dma_dev *dmadev = jz4740_dma_chan_get_dev(chan);
 272        unsigned long flags;
 273        LIST_HEAD(head);
 274
 275        spin_lock_irqsave(&chan->vchan.lock, flags);
 276        jz4740_dma_write_mask(dmadev, JZ_REG_DMA_STATUS_CTRL(chan->id), 0,
 277                        JZ_DMA_STATUS_CTRL_ENABLE);
 278        chan->desc = NULL;
 279        vchan_get_all_descriptors(&chan->vchan, &head);
 280        spin_unlock_irqrestore(&chan->vchan.lock, flags);
 281
 282        vchan_dma_desc_free_list(&chan->vchan, &head);
 283
 284        return 0;
 285}
 286
 287static int jz4740_dma_start_transfer(struct jz4740_dmaengine_chan *chan)
 288{
 289        struct jz4740_dma_dev *dmadev = jz4740_dma_chan_get_dev(chan);
 290        dma_addr_t src_addr, dst_addr;
 291        struct virt_dma_desc *vdesc;
 292        struct jz4740_dma_sg *sg;
 293
 294        jz4740_dma_write_mask(dmadev, JZ_REG_DMA_STATUS_CTRL(chan->id), 0,
 295                        JZ_DMA_STATUS_CTRL_ENABLE);
 296
 297        if (!chan->desc) {
 298                vdesc = vchan_next_desc(&chan->vchan);
 299                if (!vdesc)
 300                        return 0;
 301                chan->desc = to_jz4740_dma_desc(vdesc);
 302                chan->next_sg = 0;
 303        }
 304
 305        if (chan->next_sg == chan->desc->num_sgs)
 306                chan->next_sg = 0;
 307
 308        sg = &chan->desc->sg[chan->next_sg];
 309
 310        if (chan->desc->direction == DMA_MEM_TO_DEV) {
 311                src_addr = sg->addr;
 312                dst_addr = chan->fifo_addr;
 313        } else {
 314                src_addr = chan->fifo_addr;
 315                dst_addr = sg->addr;
 316        }
 317        jz4740_dma_write(dmadev, JZ_REG_DMA_SRC_ADDR(chan->id), src_addr);
 318        jz4740_dma_write(dmadev, JZ_REG_DMA_DST_ADDR(chan->id), dst_addr);
 319        jz4740_dma_write(dmadev, JZ_REG_DMA_TRANSFER_COUNT(chan->id),
 320                        sg->len >> chan->transfer_shift);
 321
 322        chan->next_sg++;
 323
 324        jz4740_dma_write_mask(dmadev, JZ_REG_DMA_STATUS_CTRL(chan->id),
 325                        JZ_DMA_STATUS_CTRL_NO_DESC | JZ_DMA_STATUS_CTRL_ENABLE,
 326                        JZ_DMA_STATUS_CTRL_HALT | JZ_DMA_STATUS_CTRL_NO_DESC |
 327                        JZ_DMA_STATUS_CTRL_ENABLE);
 328
 329        jz4740_dma_write_mask(dmadev, JZ_REG_DMA_CTRL,
 330                        JZ_DMA_CTRL_ENABLE,
 331                        JZ_DMA_CTRL_HALT | JZ_DMA_CTRL_ENABLE);
 332
 333        return 0;
 334}
 335
 336static void jz4740_dma_chan_irq(struct jz4740_dmaengine_chan *chan)
 337{
 338        spin_lock(&chan->vchan.lock);
 339        if (chan->desc) {
 340                if (chan->desc->cyclic) {
 341                        vchan_cyclic_callback(&chan->desc->vdesc);
 342                } else {
 343                        if (chan->next_sg == chan->desc->num_sgs) {
 344                                list_del(&chan->desc->vdesc.node);
 345                                vchan_cookie_complete(&chan->desc->vdesc);
 346                                chan->desc = NULL;
 347                        }
 348                }
 349        }
 350        jz4740_dma_start_transfer(chan);
 351        spin_unlock(&chan->vchan.lock);
 352}
 353
 354static irqreturn_t jz4740_dma_irq(int irq, void *devid)
 355{
 356        struct jz4740_dma_dev *dmadev = devid;
 357        uint32_t irq_status;
 358        unsigned int i;
 359
 360        irq_status = readl(dmadev->base + JZ_REG_DMA_IRQ);
 361
 362        for (i = 0; i < 6; ++i) {
 363                if (irq_status & (1 << i)) {
 364                        jz4740_dma_write_mask(dmadev,
 365                                JZ_REG_DMA_STATUS_CTRL(i), 0,
 366                                JZ_DMA_STATUS_CTRL_ENABLE |
 367                                JZ_DMA_STATUS_CTRL_TRANSFER_DONE);
 368
 369                        jz4740_dma_chan_irq(&dmadev->chan[i]);
 370                }
 371        }
 372
 373        return IRQ_HANDLED;
 374}
 375
 376static void jz4740_dma_issue_pending(struct dma_chan *c)
 377{
 378        struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
 379        unsigned long flags;
 380
 381        spin_lock_irqsave(&chan->vchan.lock, flags);
 382        if (vchan_issue_pending(&chan->vchan) && !chan->desc)
 383                jz4740_dma_start_transfer(chan);
 384        spin_unlock_irqrestore(&chan->vchan.lock, flags);
 385}
 386
 387static struct dma_async_tx_descriptor *jz4740_dma_prep_slave_sg(
 388        struct dma_chan *c, struct scatterlist *sgl,
 389        unsigned int sg_len, enum dma_transfer_direction direction,
 390        unsigned long flags, void *context)
 391{
 392        struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
 393        struct jz4740_dma_desc *desc;
 394        struct scatterlist *sg;
 395        unsigned int i;
 396
 397        desc = jz4740_dma_alloc_desc(sg_len);
 398        if (!desc)
 399                return NULL;
 400
 401        for_each_sg(sgl, sg, sg_len, i) {
 402                desc->sg[i].addr = sg_dma_address(sg);
 403                desc->sg[i].len = sg_dma_len(sg);
 404        }
 405
 406        desc->num_sgs = sg_len;
 407        desc->direction = direction;
 408        desc->cyclic = false;
 409
 410        return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
 411}
 412
 413static struct dma_async_tx_descriptor *jz4740_dma_prep_dma_cyclic(
 414        struct dma_chan *c, dma_addr_t buf_addr, size_t buf_len,
 415        size_t period_len, enum dma_transfer_direction direction,
 416        unsigned long flags)
 417{
 418        struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
 419        struct jz4740_dma_desc *desc;
 420        unsigned int num_periods, i;
 421
 422        if (buf_len % period_len)
 423                return NULL;
 424
 425        num_periods = buf_len / period_len;
 426
 427        desc = jz4740_dma_alloc_desc(num_periods);
 428        if (!desc)
 429                return NULL;
 430
 431        for (i = 0; i < num_periods; i++) {
 432                desc->sg[i].addr = buf_addr;
 433                desc->sg[i].len = period_len;
 434                buf_addr += period_len;
 435        }
 436
 437        desc->num_sgs = num_periods;
 438        desc->direction = direction;
 439        desc->cyclic = true;
 440
 441        return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
 442}
 443
 444static size_t jz4740_dma_desc_residue(struct jz4740_dmaengine_chan *chan,
 445        struct jz4740_dma_desc *desc, unsigned int next_sg)
 446{
 447        struct jz4740_dma_dev *dmadev = jz4740_dma_chan_get_dev(chan);
 448        unsigned int residue, count;
 449        unsigned int i;
 450
 451        residue = 0;
 452
 453        for (i = next_sg; i < desc->num_sgs; i++)
 454                residue += desc->sg[i].len;
 455
 456        if (next_sg != 0) {
 457                count = jz4740_dma_read(dmadev,
 458                        JZ_REG_DMA_TRANSFER_COUNT(chan->id));
 459                residue += count << chan->transfer_shift;
 460        }
 461
 462        return residue;
 463}
 464
 465static enum dma_status jz4740_dma_tx_status(struct dma_chan *c,
 466        dma_cookie_t cookie, struct dma_tx_state *state)
 467{
 468        struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
 469        struct virt_dma_desc *vdesc;
 470        enum dma_status status;
 471        unsigned long flags;
 472
 473        status = dma_cookie_status(c, cookie, state);
 474        if (status == DMA_COMPLETE || !state)
 475                return status;
 476
 477        spin_lock_irqsave(&chan->vchan.lock, flags);
 478        vdesc = vchan_find_desc(&chan->vchan, cookie);
 479        if (cookie == chan->desc->vdesc.tx.cookie) {
 480                state->residue = jz4740_dma_desc_residue(chan, chan->desc,
 481                                chan->next_sg);
 482        } else if (vdesc) {
 483                state->residue = jz4740_dma_desc_residue(chan,
 484                                to_jz4740_dma_desc(vdesc), 0);
 485        } else {
 486                state->residue = 0;
 487        }
 488        spin_unlock_irqrestore(&chan->vchan.lock, flags);
 489
 490        return status;
 491}
 492
 493static void jz4740_dma_free_chan_resources(struct dma_chan *c)
 494{
 495        vchan_free_chan_resources(to_virt_chan(c));
 496}
 497
 498static void jz4740_dma_desc_free(struct virt_dma_desc *vdesc)
 499{
 500        kfree(container_of(vdesc, struct jz4740_dma_desc, vdesc));
 501}
 502
 503#define JZ4740_DMA_BUSWIDTHS (BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | \
 504        BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | BIT(DMA_SLAVE_BUSWIDTH_4_BYTES))
 505
 506static int jz4740_dma_probe(struct platform_device *pdev)
 507{
 508        struct jz4740_dmaengine_chan *chan;
 509        struct jz4740_dma_dev *dmadev;
 510        struct dma_device *dd;
 511        unsigned int i;
 512        struct resource *res;
 513        int ret;
 514        int irq;
 515
 516        dmadev = devm_kzalloc(&pdev->dev, sizeof(*dmadev), GFP_KERNEL);
 517        if (!dmadev)
 518                return -EINVAL;
 519
 520        dd = &dmadev->ddev;
 521
 522        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 523        dmadev->base = devm_ioremap_resource(&pdev->dev, res);
 524        if (IS_ERR(dmadev->base))
 525                return PTR_ERR(dmadev->base);
 526
 527        dmadev->clk = clk_get(&pdev->dev, "dma");
 528        if (IS_ERR(dmadev->clk))
 529                return PTR_ERR(dmadev->clk);
 530
 531        clk_prepare_enable(dmadev->clk);
 532
 533        dma_cap_set(DMA_SLAVE, dd->cap_mask);
 534        dma_cap_set(DMA_CYCLIC, dd->cap_mask);
 535        dd->device_free_chan_resources = jz4740_dma_free_chan_resources;
 536        dd->device_tx_status = jz4740_dma_tx_status;
 537        dd->device_issue_pending = jz4740_dma_issue_pending;
 538        dd->device_prep_slave_sg = jz4740_dma_prep_slave_sg;
 539        dd->device_prep_dma_cyclic = jz4740_dma_prep_dma_cyclic;
 540        dd->device_config = jz4740_dma_slave_config;
 541        dd->device_terminate_all = jz4740_dma_terminate_all;
 542        dd->src_addr_widths = JZ4740_DMA_BUSWIDTHS;
 543        dd->dst_addr_widths = JZ4740_DMA_BUSWIDTHS;
 544        dd->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
 545        dd->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
 546        dd->dev = &pdev->dev;
 547        INIT_LIST_HEAD(&dd->channels);
 548
 549        for (i = 0; i < JZ_DMA_NR_CHANS; i++) {
 550                chan = &dmadev->chan[i];
 551                chan->id = i;
 552                chan->vchan.desc_free = jz4740_dma_desc_free;
 553                vchan_init(&chan->vchan, dd);
 554        }
 555
 556        ret = dma_async_device_register(dd);
 557        if (ret)
 558                goto err_clk;
 559
 560        irq = platform_get_irq(pdev, 0);
 561        ret = request_irq(irq, jz4740_dma_irq, 0, dev_name(&pdev->dev), dmadev);
 562        if (ret)
 563                goto err_unregister;
 564
 565        platform_set_drvdata(pdev, dmadev);
 566
 567        return 0;
 568
 569err_unregister:
 570        dma_async_device_unregister(dd);
 571err_clk:
 572        clk_disable_unprepare(dmadev->clk);
 573        return ret;
 574}
 575
 576static void jz4740_cleanup_vchan(struct dma_device *dmadev)
 577{
 578        struct jz4740_dmaengine_chan *chan, *_chan;
 579
 580        list_for_each_entry_safe(chan, _chan,
 581                                &dmadev->channels, vchan.chan.device_node) {
 582                list_del(&chan->vchan.chan.device_node);
 583                tasklet_kill(&chan->vchan.task);
 584        }
 585}
 586
 587
 588static int jz4740_dma_remove(struct platform_device *pdev)
 589{
 590        struct jz4740_dma_dev *dmadev = platform_get_drvdata(pdev);
 591        int irq = platform_get_irq(pdev, 0);
 592
 593        free_irq(irq, dmadev);
 594
 595        jz4740_cleanup_vchan(&dmadev->ddev);
 596        dma_async_device_unregister(&dmadev->ddev);
 597        clk_disable_unprepare(dmadev->clk);
 598
 599        return 0;
 600}
 601
 602static struct platform_driver jz4740_dma_driver = {
 603        .probe = jz4740_dma_probe,
 604        .remove = jz4740_dma_remove,
 605        .driver = {
 606                .name = "jz4740-dma",
 607        },
 608};
 609module_platform_driver(jz4740_dma_driver);
 610
 611MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 612MODULE_DESCRIPTION("JZ4740 DMA driver");
 613MODULE_LICENSE("GPL v2");
 614