drivers/dma/sun4i-dma.c

   1 /*
   2  * Copyright (C) 2014 Emilio López
   3  * Emilio López <emilio@elopez.com.ar>
   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 as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  */
  10
  11 #include <linux/bitmap.h>
  12 #include <linux/bitops.h>
  13 #include <linux/clk.h>
  14 #include <linux/dmaengine.h>
  15 #include <linux/dmapool.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/module.h>
  18 #include <linux/of_dma.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/slab.h>
  21 #include <linux/spinlock.h>
  22
  23 #include "virt-dma.h"
  24
  25 /** Common macros to normal and dedicated DMA registers **/
  26
  27 #define SUN4I_DMA_CFG_LOADING                   BIT(31)
  28 #define SUN4I_DMA_CFG_DST_DATA_WIDTH(width)     ((width) << 25)
  29 #define SUN4I_DMA_CFG_DST_BURST_LENGTH(len)     ((len) << 23)
  30 #define SUN4I_DMA_CFG_DST_ADDR_MODE(mode)       ((mode) << 21)
  31 #define SUN4I_DMA_CFG_DST_DRQ_TYPE(type)        ((type) << 16)
  32 #define SUN4I_DMA_CFG_SRC_DATA_WIDTH(width)     ((width) << 9)
  33 #define SUN4I_DMA_CFG_SRC_BURST_LENGTH(len)     ((len) << 7)
  34 #define SUN4I_DMA_CFG_SRC_ADDR_MODE(mode)       ((mode) << 5)
  35 #define SUN4I_DMA_CFG_SRC_DRQ_TYPE(type)        (type)
  36
  37 /** Normal DMA register values **/
  38
  39 /* Normal DMA source/destination data request type values */
  40 #define SUN4I_NDMA_DRQ_TYPE_SDRAM               0x16
  41 #define SUN4I_NDMA_DRQ_TYPE_LIMIT               (0x1F + 1)
  42
  43 /** Normal DMA register layout **/
  44
  45 /* Dedicated DMA source/destination address mode values */
  46 #define SUN4I_NDMA_ADDR_MODE_LINEAR             0
  47 #define SUN4I_NDMA_ADDR_MODE_IO                 1
  48
  49 /* Normal DMA configuration register layout */
  50 #define SUN4I_NDMA_CFG_CONT_MODE                BIT(30)
  51 #define SUN4I_NDMA_CFG_WAIT_STATE(n)            ((n) << 27)
  52 #define SUN4I_NDMA_CFG_DST_NON_SECURE           BIT(22)
  53 #define SUN4I_NDMA_CFG_BYTE_COUNT_MODE_REMAIN   BIT(15)
  54 #define SUN4I_NDMA_CFG_SRC_NON_SECURE           BIT(6)
  55
  56 /** Dedicated DMA register values **/
  57
  58 /* Dedicated DMA source/destination address mode values */
  59 #define SUN4I_DDMA_ADDR_MODE_LINEAR             0
  60 #define SUN4I_DDMA_ADDR_MODE_IO                 1
  61 #define SUN4I_DDMA_ADDR_MODE_HORIZONTAL_PAGE    2
  62 #define SUN4I_DDMA_ADDR_MODE_VERTICAL_PAGE      3
  63
  64 /* Dedicated DMA source/destination data request type values */
  65 #define SUN4I_DDMA_DRQ_TYPE_SDRAM               0x1
  66 #define SUN4I_DDMA_DRQ_TYPE_LIMIT               (0x1F + 1)
  67
  68 /** Dedicated DMA register layout **/
  69
  70 /* Dedicated DMA configuration register layout */
  71 #define SUN4I_DDMA_CFG_BUSY                     BIT(30)
  72 #define SUN4I_DDMA_CFG_CONT_MODE                BIT(29)
  73 #define SUN4I_DDMA_CFG_DST_NON_SECURE           BIT(28)
  74 #define SUN4I_DDMA_CFG_BYTE_COUNT_MODE_REMAIN   BIT(15)
  75 #define SUN4I_DDMA_CFG_SRC_NON_SECURE           BIT(12)
  76
  77 /* Dedicated DMA parameter register layout */
  78 #define SUN4I_DDMA_PARA_DST_DATA_BLK_SIZE(n)    (((n) - 1) << 24)
  79 #define SUN4I_DDMA_PARA_DST_WAIT_CYCLES(n)      (((n) - 1) << 16)
  80 #define SUN4I_DDMA_PARA_SRC_DATA_BLK_SIZE(n)    (((n) - 1) << 8)
  81 #define SUN4I_DDMA_PARA_SRC_WAIT_CYCLES(n)      (((n) - 1) << 0)
  82
  83 /** DMA register offsets **/
  84
  85 /* General register offsets */
  86 #define SUN4I_DMA_IRQ_ENABLE_REG                0x0
  87 #define SUN4I_DMA_IRQ_PENDING_STATUS_REG        0x4
  88
  89 /* Normal DMA register offsets */
  90 #define SUN4I_NDMA_CHANNEL_REG_BASE(n)          (0x100 + (n) * 0x20)
  91 #define SUN4I_NDMA_CFG_REG                      0x0
  92 #define SUN4I_NDMA_SRC_ADDR_REG                 0x4
  93 #define SUN4I_NDMA_DST_ADDR_REG         0x8
  94 #define SUN4I_NDMA_BYTE_COUNT_REG               0xC
  95
  96 /* Dedicated DMA register offsets */
  97 #define SUN4I_DDMA_CHANNEL_REG_BASE(n)          (0x300 + (n) * 0x20)
  98 #define SUN4I_DDMA_CFG_REG                      0x0
  99 #define SUN4I_DDMA_SRC_ADDR_REG                 0x4
 100 #define SUN4I_DDMA_DST_ADDR_REG         0x8
 101 #define SUN4I_DDMA_BYTE_COUNT_REG               0xC
 102 #define SUN4I_DDMA_PARA_REG                     0x18
 103
 104 /** DMA Driver **/
 105
 106 /*
 107  * Normal DMA has 8 channels, and Dedicated DMA has another 8, so
 108  * that's 16 channels. As for endpoints, there's 29 and 21
 109  * respectively. Given that the Normal DMA endpoints (other than
 110  * SDRAM) can be used as tx/rx, we need 78 vchans in total
 111  */
 112 #define SUN4I_NDMA_NR_MAX_CHANNELS      8
 113 #define SUN4I_DDMA_NR_MAX_CHANNELS      8
 114 #define SUN4I_DMA_NR_MAX_CHANNELS                                       \
 115         (SUN4I_NDMA_NR_MAX_CHANNELS + SUN4I_DDMA_NR_MAX_CHANNELS)
 116 #define SUN4I_NDMA_NR_MAX_VCHANS        (29 * 2 - 1)
 117 #define SUN4I_DDMA_NR_MAX_VCHANS        21
 118 #define SUN4I_DMA_NR_MAX_VCHANS                                         \
 119         (SUN4I_NDMA_NR_MAX_VCHANS + SUN4I_DDMA_NR_MAX_VCHANS)
 120
 121 /* This set of SUN4I_DDMA timing parameters were found experimentally while
 122  * working with the SPI driver and seem to make it behave correctly */
 123 #define SUN4I_DDMA_MAGIC_SPI_PARAMETERS \
 124         (SUN4I_DDMA_PARA_DST_DATA_BLK_SIZE(1) |                 \
 125          SUN4I_DDMA_PARA_SRC_DATA_BLK_SIZE(1) |                         \
 126          SUN4I_DDMA_PARA_DST_WAIT_CYCLES(2) |                           \
 127          SUN4I_DDMA_PARA_SRC_WAIT_CYCLES(2))
 128
 129 struct sun4i_dma_pchan {
 130         /* Register base of channel */
 131         void __iomem                    *base;
 132         /* vchan currently being serviced */
 133         struct sun4i_dma_vchan          *vchan;
 134         /* Is this a dedicated pchan? */
 135         int                             is_dedicated;
 136 };
 137
 138 struct sun4i_dma_vchan {
 139         struct virt_dma_chan            vc;
 140         struct dma_slave_config         cfg;
 141         struct sun4i_dma_pchan          *pchan;
 142         struct sun4i_dma_promise        *processing;
 143         struct sun4i_dma_contract       *contract;
 144         u8                              endpoint;
 145         int                             is_dedicated;
 146 };
 147
 148 struct sun4i_dma_promise {
 149         u32                             cfg;
 150         u32                             para;
 151         dma_addr_t                      src;
 152         dma_addr_t                      dst;
 153         size_t                          len;
 154         struct list_head                list;
 155 };
 156
 157 /* A contract is a set of promises */
 158 struct sun4i_dma_contract {
 159         struct virt_dma_desc            vd;
 160         struct list_head                demands;
 161         struct list_head                completed_demands;
 162         int                             is_cyclic;
 163 };
 164
 165 struct sun4i_dma_dev {
 166         DECLARE_BITMAP(pchans_used, SUN4I_DMA_NR_MAX_CHANNELS);
 167         struct dma_device               slave;
 168         struct sun4i_dma_pchan          *pchans;
 169         struct sun4i_dma_vchan          *vchans;
 170         void __iomem                    *base;
 171         struct clk                      *clk;
 172         int                             irq;
 173         spinlock_t                      lock;
 174 };
 175
 176 static struct sun4i_dma_dev *to_sun4i_dma_dev(struct dma_device *dev)
 177 {
 178         return container_of(dev, struct sun4i_dma_dev, slave);
 179 }
 180
 181 static struct sun4i_dma_vchan *to_sun4i_dma_vchan(struct dma_chan *chan)
 182 {
 183         return container_of(chan, struct sun4i_dma_vchan, vc.chan);
 184 }
 185
 186 static struct sun4i_dma_contract *to_sun4i_dma_contract(struct virt_dma_desc *vd)
 187 {
 188         return container_of(vd, struct sun4i_dma_contract, vd);
 189 }
 190
 191 static struct device *chan2dev(struct dma_chan *chan)
 192 {
 193         return &chan->dev->device;
 194 }
 195
 196 static int convert_burst(u32 maxburst)
 197 {
 198         if (maxburst > 8)
 199                 return -EINVAL;
 200
 201         /* 1 -> 0, 4 -> 1, 8 -> 2 */
 202         return (maxburst >> 2);
 203 }
 204
 205 static int convert_buswidth(enum dma_slave_buswidth addr_width)
 206 {
 207         if (addr_width > DMA_SLAVE_BUSWIDTH_4_BYTES)
 208                 return -EINVAL;
 209
 210         /* 8 (1 byte) -> 0, 16 (2 bytes) -> 1, 32 (4 bytes) -> 2 */
 211         return (addr_width >> 1);
 212 }
 213
 214 static void sun4i_dma_free_chan_resources(struct dma_chan *chan)
 215 {
 216         struct sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
 217
 218         vchan_free_chan_resources(&vchan->vc);
 219 }
 220
 221 static struct sun4i_dma_pchan *find_and_use_pchan(struct sun4i_dma_dev *priv,
 222                                                   struct sun4i_dma_vchan *vchan)
 223 {
 224         struct sun4i_dma_pchan *pchan = NULL, *pchans = priv->pchans;
 225         unsigned long flags;
 226         int i, max;
 227
 228         /*
 229          * pchans 0-SUN4I_NDMA_NR_MAX_CHANNELS are normal, and
 230          * SUN4I_NDMA_NR_MAX_CHANNELS+ are dedicated ones
 231          */
 232         if (vchan->is_dedicated) {
 233                 i = SUN4I_NDMA_NR_MAX_CHANNELS;
 234                 max = SUN4I_DMA_NR_MAX_CHANNELS;
 235         } else {
 236                 i = 0;
 237                 max = SUN4I_NDMA_NR_MAX_CHANNELS;
 238         }
 239
 240         spin_lock_irqsave(&priv->lock, flags);
 241         for_each_clear_bit_from(i, &priv->pchans_used, max) {
 242                 pchan = &pchans[i];
 243                 pchan->vchan = vchan;
 244                 set_bit(i, priv->pchans_used);
 245                 break;
 246         }
 247         spin_unlock_irqrestore(&priv->lock, flags);
 248
 249         return pchan;
 250 }
 251
 252 static void release_pchan(struct sun4i_dma_dev *priv,
 253                           struct sun4i_dma_pchan *pchan)
 254 {
 255         unsigned long flags;
 256         int nr = pchan - priv->pchans;
 257
 258         spin_lock_irqsave(&priv->lock, flags);
 259
 260         pchan->vchan = NULL;
 261         clear_bit(nr, priv->pchans_used);
 262
 263         spin_unlock_irqrestore(&priv->lock, flags);
 264 }
 265
 266 static void configure_pchan(struct sun4i_dma_pchan *pchan,
 267                             struct sun4i_dma_promise *d)
 268 {
 269         /*
 270          * Configure addresses and misc parameters depending on type
 271          * SUN4I_DDMA has an extra field with timing parameters
 272          */
 273         if (pchan->is_dedicated) {
 274                 writel_relaxed(d->src, pchan->base + SUN4I_DDMA_SRC_ADDR_REG);
 275                 writel_relaxed(d->dst, pchan->base + SUN4I_DDMA_DST_ADDR_REG);
 276                 writel_relaxed(d->len, pchan->base + SUN4I_DDMA_BYTE_COUNT_REG);
 277                 writel_relaxed(d->para, pchan->base + SUN4I_DDMA_PARA_REG);
 278                 writel_relaxed(d->cfg, pchan->base + SUN4I_DDMA_CFG_REG);
 279         } else {
 280                 writel_relaxed(d->src, pchan->base + SUN4I_NDMA_SRC_ADDR_REG);
 281                 writel_relaxed(d->dst, pchan->base + SUN4I_NDMA_DST_ADDR_REG);
 282                 writel_relaxed(d->len, pchan->base + SUN4I_NDMA_BYTE_COUNT_REG);
 283                 writel_relaxed(d->cfg, pchan->base + SUN4I_NDMA_CFG_REG);
 284         }
 285 }
 286
 287 static void set_pchan_interrupt(struct sun4i_dma_dev *priv,
 288                                 struct sun4i_dma_pchan *pchan,
 289                                 int half, int end)
 290 {
 291         u32 reg;
 292         int pchan_number = pchan - priv->pchans;
 293         unsigned long flags;
 294
 295         spin_lock_irqsave(&priv->lock, flags);
 296
 297         reg = readl_relaxed(priv->base + SUN4I_DMA_IRQ_ENABLE_REG);
 298
 299         if (half)
 300                 reg |= BIT(pchan_number * 2);
 301         else
 302                 reg &= ~BIT(pchan_number * 2);
 303
 304         if (end)
 305                 reg |= BIT(pchan_number * 2 + 1);
 306         else
 307                 reg &= ~BIT(pchan_number * 2 + 1);
 308
 309         writel_relaxed(reg, priv->base + SUN4I_DMA_IRQ_ENABLE_REG);
 310
 311         spin_unlock_irqrestore(&priv->lock, flags);
 312 }
 313
 314 /**
 315  * Execute pending operations on a vchan
 316  *
 317  * When given a vchan, this function will try to acquire a suitable
 318  * pchan and, if successful, will configure it to fulfill a promise
 319  * from the next pending contract.
 320  *
 321  * This function must be called with &vchan->vc.lock held.
 322  */
 323 static int __execute_vchan_pending(struct sun4i_dma_dev *priv,
 324                                    struct sun4i_dma_vchan *vchan)
 325 {
 326         struct sun4i_dma_promise *promise = NULL;
 327         struct sun4i_dma_contract *contract = NULL;
 328         struct sun4i_dma_pchan *pchan;
 329         struct virt_dma_desc *vd;
 330         int ret;
 331
 332         lockdep_assert_held(&vchan->vc.lock);
 333
 334         /* We need a pchan to do anything, so secure one if available */
 335         pchan = find_and_use_pchan(priv, vchan);
 336         if (!pchan)
 337                 return -EBUSY;
 338
 339         /*
 340          * Channel endpoints must not be repeated, so if this vchan
 341          * has already submitted some work, we can't do anything else
 342          */
 343         if (vchan->processing) {
 344                 dev_dbg(chan2dev(&vchan->vc.chan),
 345                         "processing something to this endpoint already\n");
 346                 ret = -EBUSY;
 347                 goto release_pchan;
 348         }
 349
 350         do {
 351                 /* Figure out which contract we're working with today */
 352                 vd = vchan_next_desc(&vchan->vc);
 353                 if (!vd) {
 354                         dev_dbg(chan2dev(&vchan->vc.chan),
 355                                 "No pending contract found");
 356                         ret = 0;
 357                         goto release_pchan;
 358                 }
 359
 360                 contract = to_sun4i_dma_contract(vd);
 361                 if (list_empty(&contract->demands)) {
 362                         /* The contract has been completed so mark it as such */
 363                         list_del(&contract->vd.node);
 364                         vchan_cookie_complete(&contract->vd);
 365                         dev_dbg(chan2dev(&vchan->vc.chan),
 366                                 "Empty contract found and marked complete");
 367                 }
 368         } while (list_empty(&contract->demands));
 369
 370         /* Now find out what we need to do */
 371         promise = list_first_entry(&contract->demands,
 372                                    struct sun4i_dma_promise, list);
 373         vchan->processing = promise;
 374
 375         /* ... and make it reality */
 376         if (promise) {
 377                 vchan->contract = contract;
 378                 vchan->pchan = pchan;
 379                 set_pchan_interrupt(priv, pchan, contract->is_cyclic, 1);
 380                 configure_pchan(pchan, promise);
 381         }
 382
 383         return 0;
 384
 385 release_pchan:
 386         release_pchan(priv, pchan);
 387         return ret;
 388 }
 389
 390 static int sanitize_config(struct dma_slave_config *sconfig,
 391                            enum dma_transfer_direction direction)
 392 {
 393         switch (direction) {
 394         case DMA_MEM_TO_DEV:
 395                 if ((sconfig->dst_addr_width == DMA_SLAVE_BUSWIDTH_UNDEFINED) ||
 396                     !sconfig->dst_maxburst)
 397                         return -EINVAL;
 398
 399                 if (sconfig->src_addr_width == DMA_SLAVE_BUSWIDTH_UNDEFINED)
 400                         sconfig->src_addr_width = sconfig->dst_addr_width;
 401
 402                 if (!sconfig->src_maxburst)
 403                         sconfig->src_maxburst = sconfig->dst_maxburst;
 404
 405                 break;
 406
 407         case DMA_DEV_TO_MEM:
 408                 if ((sconfig->src_addr_width == DMA_SLAVE_BUSWIDTH_UNDEFINED) ||
 409                     !sconfig->src_maxburst)
 410                         return -EINVAL;
 411
 412                 if (sconfig->dst_addr_width == DMA_SLAVE_BUSWIDTH_UNDEFINED)
 413                         sconfig->dst_addr_width = sconfig->src_addr_width;
 414
 415                 if (!sconfig->dst_maxburst)
 416                         sconfig->dst_maxburst = sconfig->src_maxburst;
 417
 418                 break;
 419         default:
 420                 return 0;
 421         }
 422
 423         return 0;
 424 }
 425
 426 /**
 427  * Generate a promise, to be used in a normal DMA contract.
 428  *
 429  * A NDMA promise contains all the information required to program the
 430  * normal part of the DMA Engine and get data copied. A non-executed
 431  * promise will live in the demands list on a contract. Once it has been
 432  * completed, it will be moved to the completed demands list for later freeing.
 433  * All linked promises will be freed when the corresponding contract is freed
 434  */
 435 static struct sun4i_dma_promise *
 436 generate_ndma_promise(struct dma_chan *chan, dma_addr_t src, dma_addr_t dest,
 437                       size_t len, struct dma_slave_config *sconfig,
 438                       enum dma_transfer_direction direction)
 439 {
 440         struct sun4i_dma_promise *promise;
 441         int ret;
 442
 443         ret = sanitize_config(sconfig, direction);
 444         if (ret)
 445                 return NULL;
 446
 447         promise = kzalloc(sizeof(*promise), GFP_NOWAIT);
 448         if (!promise)
 449                 return NULL;
 450
 451         promise->src = src;
 452         promise->dst = dest;
 453         promise->len = len;
 454         promise->cfg = SUN4I_DMA_CFG_LOADING |
 455                 SUN4I_NDMA_CFG_BYTE_COUNT_MODE_REMAIN;
 456
 457         dev_dbg(chan2dev(chan),
 458                 "src burst %d, dst burst %d, src buswidth %d, dst buswidth %d",
 459                 sconfig->src_maxburst, sconfig->dst_maxburst,
 460                 sconfig->src_addr_width, sconfig->dst_addr_width);
 461
 462         /* Source burst */
 463         ret = convert_burst(sconfig->src_maxburst);
 464         if (ret < 0)
 465                 goto fail;
 466         promise->cfg |= SUN4I_DMA_CFG_SRC_BURST_LENGTH(ret);
 467
 468         /* Destination burst */
 469         ret = convert_burst(sconfig->dst_maxburst);
 470         if (ret < 0)
 471                 goto fail;
 472         promise->cfg |= SUN4I_DMA_CFG_DST_BURST_LENGTH(ret);
 473
 474         /* Source bus width */
 475         ret = convert_buswidth(sconfig->src_addr_width);
 476         if (ret < 0)
 477                 goto fail;
 478         promise->cfg |= SUN4I_DMA_CFG_SRC_DATA_WIDTH(ret);
 479
 480         /* Destination bus width */
 481         ret = convert_buswidth(sconfig->dst_addr_width);
 482         if (ret < 0)
 483                 goto fail;
 484         promise->cfg |= SUN4I_DMA_CFG_DST_DATA_WIDTH(ret);
 485
 486         return promise;
 487
 488 fail:
 489         kfree(promise);
 490         return NULL;
 491 }
 492
 493 /**
 494  * Generate a promise, to be used in a dedicated DMA contract.
 495  *
 496  * A DDMA promise contains all the information required to program the
 497  * Dedicated part of the DMA Engine and get data copied. A non-executed
 498  * promise will live in the demands list on a contract. Once it has been
 499  * completed, it will be moved to the completed demands list for later freeing.
 500  * All linked promises will be freed when the corresponding contract is freed
 501  */
 502 static struct sun4i_dma_promise *
 503 generate_ddma_promise(struct dma_chan *chan, dma_addr_t src, dma_addr_t dest,
 504                       size_t len, struct dma_slave_config *sconfig)
 505 {
 506         struct sun4i_dma_promise *promise;
 507         int ret;
 508
 509         promise = kzalloc(sizeof(*promise), GFP_NOWAIT);
 510         if (!promise)
 511                 return NULL;
 512
 513         promise->src = src;
 514         promise->dst = dest;
 515         promise->len = len;
 516         promise->cfg = SUN4I_DMA_CFG_LOADING |
 517                 SUN4I_DDMA_CFG_BYTE_COUNT_MODE_REMAIN;
 518
 519         /* Source burst */
 520         ret = convert_burst(sconfig->src_maxburst);
 521         if (ret < 0)
 522                 goto fail;
 523         promise->cfg |= SUN4I_DMA_CFG_SRC_BURST_LENGTH(ret);
 524
 525         /* Destination burst */
 526         ret = convert_burst(sconfig->dst_maxburst);
 527         if (ret < 0)
 528                 goto fail;
 529         promise->cfg |= SUN4I_DMA_CFG_DST_BURST_LENGTH(ret);
 530
 531         /* Source bus width */
 532         ret = convert_buswidth(sconfig->src_addr_width);
 533         if (ret < 0)
 534                 goto fail;
 535         promise->cfg |= SUN4I_DMA_CFG_SRC_DATA_WIDTH(ret);
 536
 537         /* Destination bus width */
 538         ret = convert_buswidth(sconfig->dst_addr_width);
 539         if (ret < 0)
 540                 goto fail;
 541         promise->cfg |= SUN4I_DMA_CFG_DST_DATA_WIDTH(ret);
 542
 543         return promise;
 544
 545 fail:
 546         kfree(promise);
 547         return NULL;
 548 }
 549
 550 /**
 551  * Generate a contract
 552  *
 553  * Contracts function as DMA descriptors. As our hardware does not support
 554  * linked lists, we need to implement SG via software. We use a contract
 555  * to hold all the pieces of the request and process them serially one
 556  * after another. Each piece is represented as a promise.
 557  */
 558 static struct sun4i_dma_contract *generate_dma_contract(void)
 559 {
 560         struct sun4i_dma_contract *contract;
 561
 562         contract = kzalloc(sizeof(*contract), GFP_NOWAIT);
 563         if (!contract)
 564                 return NULL;
 565
 566         INIT_LIST_HEAD(&contract->demands);
 567         INIT_LIST_HEAD(&contract->completed_demands);
 568
 569         return contract;
 570 }
 571
 572 /**
 573  * Get next promise on a cyclic transfer
 574  *
 575  * Cyclic contracts contain a series of promises which are executed on a
 576  * loop. This function returns the next promise from a cyclic contract,
 577  * so it can be programmed into the hardware.
 578  */
 579 static struct sun4i_dma_promise *
 580 get_next_cyclic_promise(struct sun4i_dma_contract *contract)
 581 {
 582         struct sun4i_dma_promise *promise;
 583
 584         promise = list_first_entry_or_null(&contract->demands,
 585                                            struct sun4i_dma_promise, list);
 586         if (!promise) {
 587                 list_splice_init(&contract->completed_demands,
 588                                  &contract->demands);
 589                 promise = list_first_entry(&contract->demands,
 590                                            struct sun4i_dma_promise, list);
 591         }
 592
 593         return promise;
 594 }
 595
 596 /**
 597  * Free a contract and all its associated promises
 598  */
 599 static void sun4i_dma_free_contract(struct virt_dma_desc *vd)
 600 {
 601         struct sun4i_dma_contract *contract = to_sun4i_dma_contract(vd);
 602         struct sun4i_dma_promise *promise, *tmp;
 603
 604         /* Free all the demands and completed demands */
 605         list_for_each_entry_safe(promise, tmp, &contract->demands, list)
 606                 kfree(promise);
 607
 608         list_for_each_entry_safe(promise, tmp, &contract->completed_demands, list)
 609                 kfree(promise);
 610
 611         kfree(contract);
 612 }
 613
 614 static struct dma_async_tx_descriptor *
 615 sun4i_dma_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest,
 616                           dma_addr_t src, size_t len, unsigned long flags)
 617 {
 618         struct sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
 619         struct dma_slave_config *sconfig = &vchan->cfg;
 620         struct sun4i_dma_promise *promise;
 621         struct sun4i_dma_contract *contract;
 622
 623         contract = generate_dma_contract();
 624         if (!contract)
 625                 return NULL;
 626
 627         /*
 628          * We can only do the copy to bus aligned addresses, so
 629          * choose the best one so we get decent performance. We also
 630          * maximize the burst size for this same reason.
 631          */
 632         sconfig->src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
 633         sconfig->dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
 634         sconfig->src_maxburst = 8;
 635         sconfig->dst_maxburst = 8;
 636
 637         if (vchan->is_dedicated)
 638                 promise = generate_ddma_promise(chan, src, dest, len, sconfig);
 639         else
 640                 promise = generate_ndma_promise(chan, src, dest, len, sconfig,
 641                                                 DMA_MEM_TO_MEM);
 642
 643         if (!promise) {
 644                 kfree(contract);
 645                 return NULL;
 646         }
 647
 648         /* Configure memcpy mode */
 649         if (vchan->is_dedicated) {
 650                 promise->cfg |= SUN4I_DMA_CFG_SRC_DRQ_TYPE(SUN4I_DDMA_DRQ_TYPE_SDRAM) |
 651                                 SUN4I_DMA_CFG_DST_DRQ_TYPE(SUN4I_DDMA_DRQ_TYPE_SDRAM);
 652         } else {
 653                 promise->cfg |= SUN4I_DMA_CFG_SRC_DRQ_TYPE(SUN4I_NDMA_DRQ_TYPE_SDRAM) |
 654                                 SUN4I_DMA_CFG_DST_DRQ_TYPE(SUN4I_NDMA_DRQ_TYPE_SDRAM);
 655         }
 656
 657         /* Fill the contract with our only promise */
 658         list_add_tail(&promise->list, &contract->demands);
 659
 660         /* And add it to the vchan */
 661         return vchan_tx_prep(&vchan->vc, &contract->vd, flags);
 662 }
 663
 664 static struct dma_async_tx_descriptor *
 665 sun4i_dma_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf, size_t len,
 666                           size_t period_len, enum dma_transfer_direction dir,
 667                           unsigned long flags)
 668 {
 669         struct sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
 670         struct dma_slave_config *sconfig = &vchan->cfg;
 671         struct sun4i_dma_promise *promise;
 672         struct sun4i_dma_contract *contract;
 673         dma_addr_t src, dest;
 674         u32 endpoints;
 675         int nr_periods, offset, plength, i;
 676
 677         if (!is_slave_direction(dir)) {
 678                 dev_err(chan2dev(chan), "Invalid DMA direction\n");
 679                 return NULL;
 680         }
 681
 682         if (vchan->is_dedicated) {
 683                 /*
 684                  * As we are using this just for audio data, we need to use
 685                  * normal DMA. There is nothing stopping us from supporting
 686                  * dedicated DMA here as well, so if a client comes up and
 687                  * requires it, it will be simple to implement it.
 688                  */
 689                 dev_err(chan2dev(chan),
 690                         "Cyclic transfers are only supported on Normal DMA\n");
 691                 return NULL;
 692         }
 693
 694         contract = generate_dma_contract();
 695         if (!contract)
 696                 return NULL;
 697
 698         contract->is_cyclic = 1;
 699
 700         /* Figure out the endpoints and the address we need */
 701         if (dir == DMA_MEM_TO_DEV) {
 702                 src = buf;
 703                 dest = sconfig->dst_addr;
 704                 endpoints = SUN4I_DMA_CFG_SRC_DRQ_TYPE(SUN4I_NDMA_DRQ_TYPE_SDRAM) |
 705                             SUN4I_DMA_CFG_DST_DRQ_TYPE(vchan->endpoint) |
 706                             SUN4I_DMA_CFG_DST_ADDR_MODE(SUN4I_NDMA_ADDR_MODE_IO);
 707         } else {
 708                 src = sconfig->src_addr;
 709                 dest = buf;
 710                 endpoints = SUN4I_DMA_CFG_SRC_DRQ_TYPE(vchan->endpoint) |
 711                             SUN4I_DMA_CFG_SRC_ADDR_MODE(SUN4I_NDMA_ADDR_MODE_IO) |
 712                             SUN4I_DMA_CFG_DST_DRQ_TYPE(SUN4I_NDMA_DRQ_TYPE_SDRAM);
 713         }
 714
 715         /*
 716          * We will be using half done interrupts to make two periods
 717          * out of a promise, so we need to program the DMA engine less
 718          * often
 719          */
 720
 721         /*
 722          * The engine can interrupt on half-transfer, so we can use
 723          * this feature to program the engine half as often as if we
 724          * didn't use it (keep in mind the hardware doesn't support
 725          * linked lists).
 726          *
 727          * Say you have a set of periods (| marks the start/end, I for
 728          * interrupt, P for programming the engine to do a new
 729          * transfer), the easy but slow way would be to do
 730          *
 731          *  |---|---|---|---| (periods / promises)
 732          *  P  I,P I,P I,P  I
 733          *
 734          * Using half transfer interrupts you can do
 735          *
 736          *  |-------|-------| (promises as configured on hw)
 737          *  |---|---|---|---| (periods)
 738          *  P   I  I,P  I   I
 739          *
 740          * Which requires half the engine programming for the same
 741          * functionality.
 742          */
 743         nr_periods = DIV_ROUND_UP(len / period_len, 2);
 744         for (i = 0; i < nr_periods; i++) {
 745                 /* Calculate the offset in the buffer and the length needed */
 746                 offset = i * period_len * 2;
 747                 plength = min((len - offset), (period_len * 2));
 748                 if (dir == DMA_MEM_TO_DEV)
 749                         src = buf + offset;
 750                 else
 751                         dest = buf + offset;
 752
 753                 /* Make the promise */
 754                 promise = generate_ndma_promise(chan, src, dest,
 755                                                 plength, sconfig, dir);
 756                 if (!promise) {
 757                         /* TODO: should we free everything? */
 758                         return NULL;
 759                 }
 760                 promise->cfg |= endpoints;
 761
 762                 /* Then add it to the contract */
 763                 list_add_tail(&promise->list, &contract->demands);
 764         }
 765
 766         /* And add it to the vchan */
 767         return vchan_tx_prep(&vchan->vc, &contract->vd, flags);
 768 }
 769
 770 static struct dma_async_tx_descriptor *
 771 sun4i_dma_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
 772                         unsigned int sg_len, enum dma_transfer_direction dir,
 773                         unsigned long flags, void *context)
 774 {
 775         struct sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
 776         struct dma_slave_config *sconfig = &vchan->cfg;
 777         struct sun4i_dma_promise *promise;
 778         struct sun4i_dma_contract *contract;
 779         u8 ram_type, io_mode, linear_mode;
 780         struct scatterlist *sg;
 781         dma_addr_t srcaddr, dstaddr;
 782         u32 endpoints, para;
 783         int i;
 784
 785         if (!sgl)
 786                 return NULL;
 787
 788         if (!is_slave_direction(dir)) {
 789                 dev_err(chan2dev(chan), "Invalid DMA direction\n");
 790                 return NULL;
 791         }
 792
 793         contract = generate_dma_contract();
 794         if (!contract)
 795                 return NULL;
 796
 797         if (vchan->is_dedicated) {
 798                 io_mode = SUN4I_DDMA_ADDR_MODE_IO;
 799                 linear_mode = SUN4I_DDMA_ADDR_MODE_LINEAR;
 800                 ram_type = SUN4I_DDMA_DRQ_TYPE_SDRAM;
 801         } else {
 802                 io_mode = SUN4I_NDMA_ADDR_MODE_IO;
 803                 linear_mode = SUN4I_NDMA_ADDR_MODE_LINEAR;
 804                 ram_type = SUN4I_NDMA_DRQ_TYPE_SDRAM;
 805         }
 806
 807         if (dir == DMA_MEM_TO_DEV)
 808                 endpoints = SUN4I_DMA_CFG_DST_DRQ_TYPE(vchan->endpoint) |
 809                             SUN4I_DMA_CFG_DST_ADDR_MODE(io_mode) |
 810                             SUN4I_DMA_CFG_SRC_DRQ_TYPE(ram_type) |
 811                             SUN4I_DMA_CFG_SRC_ADDR_MODE(linear_mode);
 812         else
 813                 endpoints = SUN4I_DMA_CFG_DST_DRQ_TYPE(ram_type) |
 814                             SUN4I_DMA_CFG_DST_ADDR_MODE(linear_mode) |
 815                             SUN4I_DMA_CFG_SRC_DRQ_TYPE(vchan->endpoint) |
 816                             SUN4I_DMA_CFG_SRC_ADDR_MODE(io_mode);
 817
 818         for_each_sg(sgl, sg, sg_len, i) {
 819                 /* Figure out addresses */
 820                 if (dir == DMA_MEM_TO_DEV) {
 821                         srcaddr = sg_dma_address(sg);
 822                         dstaddr = sconfig->dst_addr;
 823                 } else {
 824                         srcaddr = sconfig->src_addr;
 825                         dstaddr = sg_dma_address(sg);
 826                 }
 827
 828                 /*
 829                  * These are the magic DMA engine timings that keep SPI going.
 830                  * I haven't seen any interface on DMAEngine to configure
 831                  * timings, and so far they seem to work for everything we
 832                  * support, so I've kept them here. I don't know if other
 833                  * devices need different timings because, as usual, we only
 834                  * have the "para" bitfield meanings, but no comment on what
 835                  * the values should be when doing a certain operation :|
 836                  */
 837                 para = SUN4I_DDMA_MAGIC_SPI_PARAMETERS;
 838
 839                 /* And make a suitable promise */
 840                 if (vchan->is_dedicated)
 841                         promise = generate_ddma_promise(chan, srcaddr, dstaddr,
 842                                                         sg_dma_len(sg),
 843                                                         sconfig);
 844                 else
 845                         promise = generate_ndma_promise(chan, srcaddr, dstaddr,
 846                                                         sg_dma_len(sg),
 847                                                         sconfig, dir);
 848
 849                 if (!promise)
 850                         return NULL; /* TODO: should we free everything? */
 851
 852                 promise->cfg |= endpoints;
 853                 promise->para = para;
 854
 855                 /* Then add it to the contract */
 856                 list_add_tail(&promise->list, &contract->demands);
 857         }
 858
 859         /*
 860          * Once we've got all the promises ready, add the contract
 861          * to the pending list on the vchan
 862          */
 863         return vchan_tx_prep(&vchan->vc, &contract->vd, flags);
 864 }
 865
 866 static int sun4i_dma_terminate_all(struct dma_chan *chan)
 867 {
 868         struct sun4i_dma_dev *priv = to_sun4i_dma_dev(chan->device);
 869         struct sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
 870         struct sun4i_dma_pchan *pchan = vchan->pchan;
 871         LIST_HEAD(head);
 872         unsigned long flags;
 873
 874         spin_lock_irqsave(&vchan->vc.lock, flags);
 875         vchan_get_all_descriptors(&vchan->vc, &head);
 876         spin_unlock_irqrestore(&vchan->vc.lock, flags);
 877
 878         /*
 879          * Clearing the configuration register will halt the pchan. Interrupts
 880          * may still trigger, so don't forget to disable them.
 881          */
 882         if (pchan) {
 883                 if (pchan->is_dedicated)
 884                         writel(0, pchan->base + SUN4I_DDMA_CFG_REG);
 885                 else
 886                         writel(0, pchan->base + SUN4I_NDMA_CFG_REG);
 887                 set_pchan_interrupt(priv, pchan, 0, 0);
 888                 release_pchan(priv, pchan);
 889         }
 890
 891         spin_lock_irqsave(&vchan->vc.lock, flags);
 892         vchan_dma_desc_free_list(&vchan->vc, &head);
 893         /* Clear these so the vchan is usable again */
 894         vchan->processing = NULL;
 895         vchan->pchan = NULL;
 896         spin_unlock_irqrestore(&vchan->vc.lock, flags);
 897
 898         return 0;
 899 }
 900
 901 static int sun4i_dma_config(struct dma_chan *chan,
 902                             struct dma_slave_config *config)
 903 {
 904         struct sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
 905
 906         memcpy(&vchan->cfg, config, sizeof(*config));
 907
 908         return 0;
 909 }
 910
 911 static struct dma_chan *sun4i_dma_of_xlate(struct of_phandle_args *dma_spec,
 912                                            struct of_dma *ofdma)
 913 {
 914         struct sun4i_dma_dev *priv = ofdma->of_dma_data;
 915         struct sun4i_dma_vchan *vchan;
 916         struct dma_chan *chan;
 917         u8 is_dedicated = dma_spec->args[0];
 918         u8 endpoint = dma_spec->args[1];
 919
 920         /* Check if type is Normal or Dedicated */
 921         if (is_dedicated != 0 && is_dedicated != 1)
 922                 return NULL;
 923
 924         /* Make sure the endpoint looks sane */
 925         if ((is_dedicated && endpoint >= SUN4I_DDMA_DRQ_TYPE_LIMIT) ||
 926             (!is_dedicated && endpoint >= SUN4I_NDMA_DRQ_TYPE_LIMIT))
 927                 return NULL;
 928
 929         chan = dma_get_any_slave_channel(&priv->slave);
 930         if (!chan)
 931                 return NULL;
 932
 933         /* Assign the endpoint to the vchan */
 934         vchan = to_sun4i_dma_vchan(chan);
 935         vchan->is_dedicated = is_dedicated;
 936         vchan->endpoint = endpoint;
 937
 938         return chan;
 939 }
 940
 941 static enum dma_status sun4i_dma_tx_status(struct dma_chan *chan,
 942                                            dma_cookie_t cookie,
 943                                            struct dma_tx_state *state)
 944 {
 945         struct sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
 946         struct sun4i_dma_pchan *pchan = vchan->pchan;
 947         struct sun4i_dma_contract *contract;
 948         struct sun4i_dma_promise *promise;
 949         struct virt_dma_desc *vd;
 950         unsigned long flags;
 951         enum dma_status ret;
 952         size_t bytes = 0;
 953
 954         ret = dma_cookie_status(chan, cookie, state);
 955         if (!state || (ret == DMA_COMPLETE))
 956                 return ret;
 957
 958         spin_lock_irqsave(&vchan->vc.lock, flags);
 959         vd = vchan_find_desc(&vchan->vc, cookie);
 960         if (!vd)
 961                 goto exit;
 962         contract = to_sun4i_dma_contract(vd);
 963
 964         list_for_each_entry(promise, &contract->demands, list)
 965                 bytes += promise->len;
 966
 967         /*
 968          * The hardware is configured to return the remaining byte
 969          * quantity. If possible, replace the first listed element's
 970          * full size with the actual remaining amount
 971          */
 972         promise = list_first_entry_or_null(&contract->demands,
 973                                            struct sun4i_dma_promise, list);
 974         if (promise && pchan) {
 975                 bytes -= promise->len;
 976                 if (pchan->is_dedicated)
 977                         bytes += readl(pchan->base + SUN4I_DDMA_BYTE_COUNT_REG);
 978                 else
 979                         bytes += readl(pchan->base + SUN4I_NDMA_BYTE_COUNT_REG);
 980         }
 981
 982 exit:
 983
 984         dma_set_residue(state, bytes);
 985         spin_unlock_irqrestore(&vchan->vc.lock, flags);
 986
 987         return ret;
 988 }
 989
 990 static void sun4i_dma_issue_pending(struct dma_chan *chan)
 991 {
 992         struct sun4i_dma_dev *priv = to_sun4i_dma_dev(chan->device);
 993         struct sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
 994         unsigned long flags;
 995
 996         spin_lock_irqsave(&vchan->vc.lock, flags);
 997
 998         /*
 999          * If there are pending transactions for this vchan, push one of
1000          * them into the engine to get the ball rolling.
1001          */
1002         if (vchan_issue_pending(&vchan->vc))
1003                 __execute_vchan_pending(priv, vchan);
1004
1005         spin_unlock_irqrestore(&vchan->vc.lock, flags);
1006 }
1007
1008 static irqreturn_t sun4i_dma_interrupt(int irq, void *dev_id)
1009 {
1010         struct sun4i_dma_dev *priv = dev_id;
1011         struct sun4i_dma_pchan *pchans = priv->pchans, *pchan;
1012         struct sun4i_dma_vchan *vchan;
1013         struct sun4i_dma_contract *contract;
1014         struct sun4i_dma_promise *promise;
1015         unsigned long pendirq, irqs, disableirqs;
1016         int bit, i, free_room, allow_mitigation = 1;
1017
1018         pendirq = readl_relaxed(priv->base + SUN4I_DMA_IRQ_PENDING_STATUS_REG);
1019
1020 handle_pending:
1021
1022         disableirqs = 0;
1023         free_room = 0;
1024
1025         for_each_set_bit(bit, &pendirq, 32) {
1026                 pchan = &pchans[bit >> 1];
1027                 vchan = pchan->vchan;
1028                 if (!vchan) /* a terminated channel may still interrupt */
1029                         continue;
1030                 contract = vchan->contract;
1031
1032                 /*
1033                  * Disable the IRQ and free the pchan if it's an end
1034                  * interrupt (odd bit)
1035                  */
1036                 if (bit & 1) {
1037                         spin_lock(&vchan->vc.lock);
1038
1039                         /*
1040                          * Move the promise into the completed list now that
1041                          * we're done with it
1042                          */
1043                         list_del(&vchan->processing->list);
1044                         list_add_tail(&vchan->processing->list,
1045                                       &contract->completed_demands);
1046
1047                         /*
1048                          * Cyclic DMA transfers are special:
1049                          * - There's always something we can dispatch
1050                          * - We need to run the callback
1051                          * - Latency is very important, as this is used by audio
1052                          * We therefore just cycle through the list and dispatch
1053                          * whatever we have here, reusing the pchan. There's
1054                          * no need to run the thread after this.
1055                          *
1056                          * For non-cyclic transfers we need to look around,
1057                          * so we can program some more work, or notify the
1058                          * client that their transfers have been completed.
1059                          */
1060                         if (contract->is_cyclic) {
1061                                 promise = get_next_cyclic_promise(contract);
1062                                 vchan->processing = promise;
1063                                 configure_pchan(pchan, promise);
1064                                 vchan_cyclic_callback(&contract->vd);
1065                         } else {
1066                                 vchan->processing = NULL;
1067                                 vchan->pchan = NULL;
1068
1069                                 free_room = 1;
1070                                 disableirqs |= BIT(bit);
1071                                 release_pchan(priv, pchan);
1072                         }
1073
1074                         spin_unlock(&vchan->vc.lock);
1075                 } else {
1076                         /* Half done interrupt */
1077                         if (contract->is_cyclic)
1078                                 vchan_cyclic_callback(&contract->vd);
1079                         else
1080                                 disableirqs |= BIT(bit);
1081                 }
1082         }
1083
1084         /* Disable the IRQs for events we handled */
1085         spin_lock(&priv->lock);
1086         irqs = readl_relaxed(priv->base + SUN4I_DMA_IRQ_ENABLE_REG);
1087         writel_relaxed(irqs & ~disableirqs,
1088                        priv->base + SUN4I_DMA_IRQ_ENABLE_REG);
1089         spin_unlock(&priv->lock);
1090
1091         /* Writing 1 to the pending field will clear the pending interrupt */
1092         writel_relaxed(pendirq, priv->base + SUN4I_DMA_IRQ_PENDING_STATUS_REG);
1093
1094         /*
1095          * If a pchan was freed, we may be able to schedule something else,
1096          * so have a look around
1097          */
1098         if (free_room) {
1099                 for (i = 0; i < SUN4I_DMA_NR_MAX_VCHANS; i++) {
1100                         vchan = &priv->vchans[i];
1101                         spin_lock(&vchan->vc.lock);
1102                         __execute_vchan_pending(priv, vchan);
1103                         spin_unlock(&vchan->vc.lock);
1104                 }
1105         }
1106
1107         /*
1108          * Handle newer interrupts if some showed up, but only do it once
1109          * to avoid a too long a loop
1110          */
1111         if (allow_mitigation) {
1112                 pendirq = readl_relaxed(priv->base +
1113                                         SUN4I_DMA_IRQ_PENDING_STATUS_REG);
1114                 if (pendirq) {
1115                         allow_mitigation = 0;
1116                         goto handle_pending;
1117                 }
1118         }
1119
1120         return IRQ_HANDLED;
1121 }
1122
1123 static int sun4i_dma_probe(struct platform_device *pdev)
1124 {
1125         struct sun4i_dma_dev *priv;
1126         struct resource *res;
1127         int i, j, ret;
1128
1129         priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
1130         if (!priv)
1131                 return -ENOMEM;
1132
1133         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1134         priv->base = devm_ioremap_resource(&pdev->dev, res);
1135         if (IS_ERR(priv->base))
1136                 return PTR_ERR(priv->base);
1137
1138         priv->irq = platform_get_irq(pdev, 0);
1139         if (priv->irq < 0) {
1140                 dev_err(&pdev->dev, "Cannot claim IRQ\n");
1141                 return priv->irq;
1142         }
1143
1144         priv->clk = devm_clk_get(&pdev->dev, NULL);
1145         if (IS_ERR(priv->clk)) {
1146                 dev_err(&pdev->dev, "No clock specified\n");
1147                 return PTR_ERR(priv->clk);
1148         }
1149
1150         platform_set_drvdata(pdev, priv);
1151         spin_lock_init(&priv->lock);
1152
1153         dma_cap_zero(priv->slave.cap_mask);
1154         dma_cap_set(DMA_PRIVATE, priv->slave.cap_mask);
1155         dma_cap_set(DMA_MEMCPY, priv->slave.cap_mask);
1156         dma_cap_set(DMA_CYCLIC, priv->slave.cap_mask);
1157         dma_cap_set(DMA_SLAVE, priv->slave.cap_mask);
1158
1159         INIT_LIST_HEAD(&priv->slave.channels);
1160         priv->slave.device_free_chan_resources  = sun4i_dma_free_chan_resources;
1161         priv->slave.device_tx_status            = sun4i_dma_tx_status;
1162         priv->slave.device_issue_pending        = sun4i_dma_issue_pending;
1163         priv->slave.device_prep_slave_sg        = sun4i_dma_prep_slave_sg;
1164         priv->slave.device_prep_dma_memcpy      = sun4i_dma_prep_dma_memcpy;
1165         priv->slave.device_prep_dma_cyclic      = sun4i_dma_prep_dma_cyclic;
1166         priv->slave.device_config               = sun4i_dma_config;
1167         priv->slave.device_terminate_all        = sun4i_dma_terminate_all;
1168         priv->slave.copy_align                  = 2;
1169         priv->slave.src_addr_widths             = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
1170                                                   BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
1171                                                   BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
1172         priv->slave.dst_addr_widths             = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
1173                                                   BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
1174                                                   BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
1175         priv->slave.directions                  = BIT(DMA_DEV_TO_MEM) |
1176                                                   BIT(DMA_MEM_TO_DEV);
1177         priv->slave.residue_granularity         = DMA_RESIDUE_GRANULARITY_BURST;
1178
1179         priv->slave.dev = &pdev->dev;
1180
1181         priv->pchans = devm_kcalloc(&pdev->dev, SUN4I_DMA_NR_MAX_CHANNELS,
1182                                     sizeof(struct sun4i_dma_pchan), GFP_KERNEL);
1183         priv->vchans = devm_kcalloc(&pdev->dev, SUN4I_DMA_NR_MAX_VCHANS,
1184                                     sizeof(struct sun4i_dma_vchan), GFP_KERNEL);
1185         if (!priv->vchans || !priv->pchans)
1186                 return -ENOMEM;
1187
1188         /*
1189          * [0..SUN4I_NDMA_NR_MAX_CHANNELS) are normal pchans, and
1190          * [SUN4I_NDMA_NR_MAX_CHANNELS..SUN4I_DMA_NR_MAX_CHANNELS) are
1191          * dedicated ones
1192          */
1193         for (i = 0; i < SUN4I_NDMA_NR_MAX_CHANNELS; i++)
1194                 priv->pchans[i].base = priv->base +
1195                         SUN4I_NDMA_CHANNEL_REG_BASE(i);
1196
1197         for (j = 0; i < SUN4I_DMA_NR_MAX_CHANNELS; i++, j++) {
1198                 priv->pchans[i].base = priv->base +
1199                         SUN4I_DDMA_CHANNEL_REG_BASE(j);
1200                 priv->pchans[i].is_dedicated = 1;
1201         }
1202
1203         for (i = 0; i < SUN4I_DMA_NR_MAX_VCHANS; i++) {
1204                 struct sun4i_dma_vchan *vchan = &priv->vchans[i];
1205
1206                 spin_lock_init(&vchan->vc.lock);
1207                 vchan->vc.desc_free = sun4i_dma_free_contract;
1208                 vchan_init(&vchan->vc, &priv->slave);
1209         }
1210
1211         ret = clk_prepare_enable(priv->clk);
1212         if (ret) {
1213                 dev_err(&pdev->dev, "Couldn't enable the clock\n");
1214                 return ret;
1215         }
1216
1217         /*
1218          * Make sure the IRQs are all disabled and accounted for. The bootloader
1219          * likes to leave these dirty
1220          */
1221         writel(0, priv->base + SUN4I_DMA_IRQ_ENABLE_REG);
1222         writel(0xFFFFFFFF, priv->base + SUN4I_DMA_IRQ_PENDING_STATUS_REG);
1223
1224         ret = devm_request_irq(&pdev->dev, priv->irq, sun4i_dma_interrupt,
1225                                0, dev_name(&pdev->dev), priv);
1226         if (ret) {
1227                 dev_err(&pdev->dev, "Cannot request IRQ\n");
1228                 goto err_clk_disable;
1229         }
1230
1231         ret = dma_async_device_register(&priv->slave);
1232         if (ret) {
1233                 dev_warn(&pdev->dev, "Failed to register DMA engine device\n");
1234                 goto err_clk_disable;
1235         }
1236
1237         ret = of_dma_controller_register(pdev->dev.of_node, sun4i_dma_of_xlate,
1238                                          priv);
1239         if (ret) {
1240                 dev_err(&pdev->dev, "of_dma_controller_register failed\n");
1241                 goto err_dma_unregister;
1242         }
1243
1244         dev_dbg(&pdev->dev, "Successfully probed SUN4I_DMA\n");
1245
1246         return 0;
1247
1248 err_dma_unregister:
1249         dma_async_device_unregister(&priv->slave);
1250 err_clk_disable:
1251         clk_disable_unprepare(priv->clk);
1252         return ret;
1253 }
1254
1255 static int sun4i_dma_remove(struct platform_device *pdev)
1256 {
1257         struct sun4i_dma_dev *priv = platform_get_drvdata(pdev);
1258
1259         /* Disable IRQ so no more work is scheduled */
1260         disable_irq(priv->irq);
1261
1262         of_dma_controller_free(pdev->dev.of_node);
1263         dma_async_device_unregister(&priv->slave);
1264
1265         clk_disable_unprepare(priv->clk);
1266
1267         return 0;
1268 }
1269
1270 static const struct of_device_id sun4i_dma_match[] = {
1271         { .compatible = "allwinner,sun4i-a10-dma" },
1272         { /* sentinel */ },
1273 };
1274 MODULE_DEVICE_TABLE(of, sun4i_dma_match);
1275
1276 static struct platform_driver sun4i_dma_driver = {
1277         .probe  = sun4i_dma_probe,
1278         .remove = sun4i_dma_remove,
1279         .driver = {
1280                 .name           = "sun4i-dma",
1281                 .of_match_table = sun4i_dma_match,
1282         },
1283 };
1284
1285 module_platform_driver(sun4i_dma_driver);
1286
1287 MODULE_DESCRIPTION("Allwinner A10 Dedicated DMA Controller Driver");
1288 MODULE_AUTHOR("Emilio López <emilio@elopez.com.ar>");
1289 MODULE_LICENSE("GPL");