linux/drivers/dma/sun6i-dma.c
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   1/*
   2 * Copyright (C) 2013-2014 Allwinner Tech Co., Ltd
   3 * Author: Sugar <shuge@allwinnertech.com>
   4 *
   5 * Copyright (C) 2014 Maxime Ripard
   6 * Maxime Ripard <maxime.ripard@free-electrons.com>
   7 *
   8 * This program is free software; you can redistribute it and/or modify
   9 * it under the terms of the GNU General Public License as published by
  10 * the Free Software Foundation; either version 2 of the License, or
  11 * (at your option) any later version.
  12 */
  13
  14#include <linux/clk.h>
  15#include <linux/delay.h>
  16#include <linux/dmaengine.h>
  17#include <linux/dmapool.h>
  18#include <linux/interrupt.h>
  19#include <linux/module.h>
  20#include <linux/of_dma.h>
  21#include <linux/of_device.h>
  22#include <linux/platform_device.h>
  23#include <linux/reset.h>
  24#include <linux/slab.h>
  25#include <linux/types.h>
  26
  27#include "virt-dma.h"
  28
  29/*
  30 * Common registers
  31 */
  32#define DMA_IRQ_EN(x)           ((x) * 0x04)
  33#define DMA_IRQ_HALF                    BIT(0)
  34#define DMA_IRQ_PKG                     BIT(1)
  35#define DMA_IRQ_QUEUE                   BIT(2)
  36
  37#define DMA_IRQ_CHAN_NR                 8
  38#define DMA_IRQ_CHAN_WIDTH              4
  39
  40
  41#define DMA_IRQ_STAT(x)         ((x) * 0x04 + 0x10)
  42
  43#define DMA_STAT                0x30
  44
  45/*
  46 * sun8i specific registers
  47 */
  48#define SUN8I_DMA_GATE          0x20
  49#define SUN8I_DMA_GATE_ENABLE   0x4
  50
  51/*
  52 * Channels specific registers
  53 */
  54#define DMA_CHAN_ENABLE         0x00
  55#define DMA_CHAN_ENABLE_START           BIT(0)
  56#define DMA_CHAN_ENABLE_STOP            0
  57
  58#define DMA_CHAN_PAUSE          0x04
  59#define DMA_CHAN_PAUSE_PAUSE            BIT(1)
  60#define DMA_CHAN_PAUSE_RESUME           0
  61
  62#define DMA_CHAN_LLI_ADDR       0x08
  63
  64#define DMA_CHAN_CUR_CFG        0x0c
  65#define DMA_CHAN_CFG_SRC_DRQ(x)         ((x) & 0x1f)
  66#define DMA_CHAN_CFG_SRC_IO_MODE        BIT(5)
  67#define DMA_CHAN_CFG_SRC_LINEAR_MODE    (0 << 5)
  68#define DMA_CHAN_CFG_SRC_BURST(x)       (((x) & 0x3) << 7)
  69#define DMA_CHAN_CFG_SRC_WIDTH(x)       (((x) & 0x3) << 9)
  70
  71#define DMA_CHAN_CFG_DST_DRQ(x)         (DMA_CHAN_CFG_SRC_DRQ(x) << 16)
  72#define DMA_CHAN_CFG_DST_IO_MODE        (DMA_CHAN_CFG_SRC_IO_MODE << 16)
  73#define DMA_CHAN_CFG_DST_LINEAR_MODE    (DMA_CHAN_CFG_SRC_LINEAR_MODE << 16)
  74#define DMA_CHAN_CFG_DST_BURST(x)       (DMA_CHAN_CFG_SRC_BURST(x) << 16)
  75#define DMA_CHAN_CFG_DST_WIDTH(x)       (DMA_CHAN_CFG_SRC_WIDTH(x) << 16)
  76
  77#define DMA_CHAN_CUR_SRC        0x10
  78
  79#define DMA_CHAN_CUR_DST        0x14
  80
  81#define DMA_CHAN_CUR_CNT        0x18
  82
  83#define DMA_CHAN_CUR_PARA       0x1c
  84
  85
  86/*
  87 * Various hardware related defines
  88 */
  89#define LLI_LAST_ITEM   0xfffff800
  90#define NORMAL_WAIT     8
  91#define DRQ_SDRAM       1
  92
  93/*
  94 * Hardware channels / ports representation
  95 *
  96 * The hardware is used in several SoCs, with differing numbers
  97 * of channels and endpoints. This structure ties those numbers
  98 * to a certain compatible string.
  99 */
 100struct sun6i_dma_config {
 101        u32 nr_max_channels;
 102        u32 nr_max_requests;
 103        u32 nr_max_vchans;
 104};
 105
 106/*
 107 * Hardware representation of the LLI
 108 *
 109 * The hardware will be fed the physical address of this structure,
 110 * and read its content in order to start the transfer.
 111 */
 112struct sun6i_dma_lli {
 113        u32                     cfg;
 114        u32                     src;
 115        u32                     dst;
 116        u32                     len;
 117        u32                     para;
 118        u32                     p_lli_next;
 119
 120        /*
 121         * This field is not used by the DMA controller, but will be
 122         * used by the CPU to go through the list (mostly for dumping
 123         * or freeing it).
 124         */
 125        struct sun6i_dma_lli    *v_lli_next;
 126};
 127
 128
 129struct sun6i_desc {
 130        struct virt_dma_desc    vd;
 131        dma_addr_t              p_lli;
 132        struct sun6i_dma_lli    *v_lli;
 133};
 134
 135struct sun6i_pchan {
 136        u32                     idx;
 137        void __iomem            *base;
 138        struct sun6i_vchan      *vchan;
 139        struct sun6i_desc       *desc;
 140        struct sun6i_desc       *done;
 141};
 142
 143struct sun6i_vchan {
 144        struct virt_dma_chan    vc;
 145        struct list_head        node;
 146        struct dma_slave_config cfg;
 147        struct sun6i_pchan      *phy;
 148        u8                      port;
 149        u8                      irq_type;
 150        bool                    cyclic;
 151};
 152
 153struct sun6i_dma_dev {
 154        struct dma_device       slave;
 155        void __iomem            *base;
 156        struct clk              *clk;
 157        int                     irq;
 158        spinlock_t              lock;
 159        struct reset_control    *rstc;
 160        struct tasklet_struct   task;
 161        atomic_t                tasklet_shutdown;
 162        struct list_head        pending;
 163        struct dma_pool         *pool;
 164        struct sun6i_pchan      *pchans;
 165        struct sun6i_vchan      *vchans;
 166        const struct sun6i_dma_config *cfg;
 167};
 168
 169static struct device *chan2dev(struct dma_chan *chan)
 170{
 171        return &chan->dev->device;
 172}
 173
 174static inline struct sun6i_dma_dev *to_sun6i_dma_dev(struct dma_device *d)
 175{
 176        return container_of(d, struct sun6i_dma_dev, slave);
 177}
 178
 179static inline struct sun6i_vchan *to_sun6i_vchan(struct dma_chan *chan)
 180{
 181        return container_of(chan, struct sun6i_vchan, vc.chan);
 182}
 183
 184static inline struct sun6i_desc *
 185to_sun6i_desc(struct dma_async_tx_descriptor *tx)
 186{
 187        return container_of(tx, struct sun6i_desc, vd.tx);
 188}
 189
 190static inline void sun6i_dma_dump_com_regs(struct sun6i_dma_dev *sdev)
 191{
 192        dev_dbg(sdev->slave.dev, "Common register:\n"
 193                "\tmask0(%04x): 0x%08x\n"
 194                "\tmask1(%04x): 0x%08x\n"
 195                "\tpend0(%04x): 0x%08x\n"
 196                "\tpend1(%04x): 0x%08x\n"
 197                "\tstats(%04x): 0x%08x\n",
 198                DMA_IRQ_EN(0), readl(sdev->base + DMA_IRQ_EN(0)),
 199                DMA_IRQ_EN(1), readl(sdev->base + DMA_IRQ_EN(1)),
 200                DMA_IRQ_STAT(0), readl(sdev->base + DMA_IRQ_STAT(0)),
 201                DMA_IRQ_STAT(1), readl(sdev->base + DMA_IRQ_STAT(1)),
 202                DMA_STAT, readl(sdev->base + DMA_STAT));
 203}
 204
 205static inline void sun6i_dma_dump_chan_regs(struct sun6i_dma_dev *sdev,
 206                                            struct sun6i_pchan *pchan)
 207{
 208        phys_addr_t reg = virt_to_phys(pchan->base);
 209
 210        dev_dbg(sdev->slave.dev, "Chan %d reg: %pa\n"
 211                "\t___en(%04x): \t0x%08x\n"
 212                "\tpause(%04x): \t0x%08x\n"
 213                "\tstart(%04x): \t0x%08x\n"
 214                "\t__cfg(%04x): \t0x%08x\n"
 215                "\t__src(%04x): \t0x%08x\n"
 216                "\t__dst(%04x): \t0x%08x\n"
 217                "\tcount(%04x): \t0x%08x\n"
 218                "\t_para(%04x): \t0x%08x\n\n",
 219                pchan->idx, &reg,
 220                DMA_CHAN_ENABLE,
 221                readl(pchan->base + DMA_CHAN_ENABLE),
 222                DMA_CHAN_PAUSE,
 223                readl(pchan->base + DMA_CHAN_PAUSE),
 224                DMA_CHAN_LLI_ADDR,
 225                readl(pchan->base + DMA_CHAN_LLI_ADDR),
 226                DMA_CHAN_CUR_CFG,
 227                readl(pchan->base + DMA_CHAN_CUR_CFG),
 228                DMA_CHAN_CUR_SRC,
 229                readl(pchan->base + DMA_CHAN_CUR_SRC),
 230                DMA_CHAN_CUR_DST,
 231                readl(pchan->base + DMA_CHAN_CUR_DST),
 232                DMA_CHAN_CUR_CNT,
 233                readl(pchan->base + DMA_CHAN_CUR_CNT),
 234                DMA_CHAN_CUR_PARA,
 235                readl(pchan->base + DMA_CHAN_CUR_PARA));
 236}
 237
 238static inline s8 convert_burst(u32 maxburst)
 239{
 240        switch (maxburst) {
 241        case 1:
 242                return 0;
 243        case 8:
 244                return 2;
 245        default:
 246                return -EINVAL;
 247        }
 248}
 249
 250static inline s8 convert_buswidth(enum dma_slave_buswidth addr_width)
 251{
 252        if ((addr_width < DMA_SLAVE_BUSWIDTH_1_BYTE) ||
 253            (addr_width > DMA_SLAVE_BUSWIDTH_4_BYTES))
 254                return -EINVAL;
 255
 256        return addr_width >> 1;
 257}
 258
 259static size_t sun6i_get_chan_size(struct sun6i_pchan *pchan)
 260{
 261        struct sun6i_desc *txd = pchan->desc;
 262        struct sun6i_dma_lli *lli;
 263        size_t bytes;
 264        dma_addr_t pos;
 265
 266        pos = readl(pchan->base + DMA_CHAN_LLI_ADDR);
 267        bytes = readl(pchan->base + DMA_CHAN_CUR_CNT);
 268
 269        if (pos == LLI_LAST_ITEM)
 270                return bytes;
 271
 272        for (lli = txd->v_lli; lli; lli = lli->v_lli_next) {
 273                if (lli->p_lli_next == pos) {
 274                        for (lli = lli->v_lli_next; lli; lli = lli->v_lli_next)
 275                                bytes += lli->len;
 276                        break;
 277                }
 278        }
 279
 280        return bytes;
 281}
 282
 283static void *sun6i_dma_lli_add(struct sun6i_dma_lli *prev,
 284                               struct sun6i_dma_lli *next,
 285                               dma_addr_t next_phy,
 286                               struct sun6i_desc *txd)
 287{
 288        if ((!prev && !txd) || !next)
 289                return NULL;
 290
 291        if (!prev) {
 292                txd->p_lli = next_phy;
 293                txd->v_lli = next;
 294        } else {
 295                prev->p_lli_next = next_phy;
 296                prev->v_lli_next = next;
 297        }
 298
 299        next->p_lli_next = LLI_LAST_ITEM;
 300        next->v_lli_next = NULL;
 301
 302        return next;
 303}
 304
 305static inline void sun6i_dma_dump_lli(struct sun6i_vchan *vchan,
 306                                      struct sun6i_dma_lli *lli)
 307{
 308        phys_addr_t p_lli = virt_to_phys(lli);
 309
 310        dev_dbg(chan2dev(&vchan->vc.chan),
 311                "\n\tdesc:   p - %pa v - 0x%p\n"
 312                "\t\tc - 0x%08x s - 0x%08x d - 0x%08x\n"
 313                "\t\tl - 0x%08x p - 0x%08x n - 0x%08x\n",
 314                &p_lli, lli,
 315                lli->cfg, lli->src, lli->dst,
 316                lli->len, lli->para, lli->p_lli_next);
 317}
 318
 319static void sun6i_dma_free_desc(struct virt_dma_desc *vd)
 320{
 321        struct sun6i_desc *txd = to_sun6i_desc(&vd->tx);
 322        struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(vd->tx.chan->device);
 323        struct sun6i_dma_lli *v_lli, *v_next;
 324        dma_addr_t p_lli, p_next;
 325
 326        if (unlikely(!txd))
 327                return;
 328
 329        p_lli = txd->p_lli;
 330        v_lli = txd->v_lli;
 331
 332        while (v_lli) {
 333                v_next = v_lli->v_lli_next;
 334                p_next = v_lli->p_lli_next;
 335
 336                dma_pool_free(sdev->pool, v_lli, p_lli);
 337
 338                v_lli = v_next;
 339                p_lli = p_next;
 340        }
 341
 342        kfree(txd);
 343}
 344
 345static int sun6i_dma_start_desc(struct sun6i_vchan *vchan)
 346{
 347        struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(vchan->vc.chan.device);
 348        struct virt_dma_desc *desc = vchan_next_desc(&vchan->vc);
 349        struct sun6i_pchan *pchan = vchan->phy;
 350        u32 irq_val, irq_reg, irq_offset;
 351
 352        if (!pchan)
 353                return -EAGAIN;
 354
 355        if (!desc) {
 356                pchan->desc = NULL;
 357                pchan->done = NULL;
 358                return -EAGAIN;
 359        }
 360
 361        list_del(&desc->node);
 362
 363        pchan->desc = to_sun6i_desc(&desc->tx);
 364        pchan->done = NULL;
 365
 366        sun6i_dma_dump_lli(vchan, pchan->desc->v_lli);
 367
 368        irq_reg = pchan->idx / DMA_IRQ_CHAN_NR;
 369        irq_offset = pchan->idx % DMA_IRQ_CHAN_NR;
 370
 371        vchan->irq_type = vchan->cyclic ? DMA_IRQ_PKG : DMA_IRQ_QUEUE;
 372
 373        irq_val = readl(sdev->base + DMA_IRQ_EN(irq_reg));
 374        irq_val &= ~((DMA_IRQ_HALF | DMA_IRQ_PKG | DMA_IRQ_QUEUE) <<
 375                        (irq_offset * DMA_IRQ_CHAN_WIDTH));
 376        irq_val |= vchan->irq_type << (irq_offset * DMA_IRQ_CHAN_WIDTH);
 377        writel(irq_val, sdev->base + DMA_IRQ_EN(irq_reg));
 378
 379        writel(pchan->desc->p_lli, pchan->base + DMA_CHAN_LLI_ADDR);
 380        writel(DMA_CHAN_ENABLE_START, pchan->base + DMA_CHAN_ENABLE);
 381
 382        sun6i_dma_dump_com_regs(sdev);
 383        sun6i_dma_dump_chan_regs(sdev, pchan);
 384
 385        return 0;
 386}
 387
 388static void sun6i_dma_tasklet(unsigned long data)
 389{
 390        struct sun6i_dma_dev *sdev = (struct sun6i_dma_dev *)data;
 391        const struct sun6i_dma_config *cfg = sdev->cfg;
 392        struct sun6i_vchan *vchan;
 393        struct sun6i_pchan *pchan;
 394        unsigned int pchan_alloc = 0;
 395        unsigned int pchan_idx;
 396
 397        list_for_each_entry(vchan, &sdev->slave.channels, vc.chan.device_node) {
 398                spin_lock_irq(&vchan->vc.lock);
 399
 400                pchan = vchan->phy;
 401
 402                if (pchan && pchan->done) {
 403                        if (sun6i_dma_start_desc(vchan)) {
 404                                /*
 405                                 * No current txd associated with this channel
 406                                 */
 407                                dev_dbg(sdev->slave.dev, "pchan %u: free\n",
 408                                        pchan->idx);
 409
 410                                /* Mark this channel free */
 411                                vchan->phy = NULL;
 412                                pchan->vchan = NULL;
 413                        }
 414                }
 415                spin_unlock_irq(&vchan->vc.lock);
 416        }
 417
 418        spin_lock_irq(&sdev->lock);
 419        for (pchan_idx = 0; pchan_idx < cfg->nr_max_channels; pchan_idx++) {
 420                pchan = &sdev->pchans[pchan_idx];
 421
 422                if (pchan->vchan || list_empty(&sdev->pending))
 423                        continue;
 424
 425                vchan = list_first_entry(&sdev->pending,
 426                                         struct sun6i_vchan, node);
 427
 428                /* Remove from pending channels */
 429                list_del_init(&vchan->node);
 430                pchan_alloc |= BIT(pchan_idx);
 431
 432                /* Mark this channel allocated */
 433                pchan->vchan = vchan;
 434                vchan->phy = pchan;
 435                dev_dbg(sdev->slave.dev, "pchan %u: alloc vchan %p\n",
 436                        pchan->idx, &vchan->vc);
 437        }
 438        spin_unlock_irq(&sdev->lock);
 439
 440        for (pchan_idx = 0; pchan_idx < cfg->nr_max_channels; pchan_idx++) {
 441                if (!(pchan_alloc & BIT(pchan_idx)))
 442                        continue;
 443
 444                pchan = sdev->pchans + pchan_idx;
 445                vchan = pchan->vchan;
 446                if (vchan) {
 447                        spin_lock_irq(&vchan->vc.lock);
 448                        sun6i_dma_start_desc(vchan);
 449                        spin_unlock_irq(&vchan->vc.lock);
 450                }
 451        }
 452}
 453
 454static irqreturn_t sun6i_dma_interrupt(int irq, void *dev_id)
 455{
 456        struct sun6i_dma_dev *sdev = dev_id;
 457        struct sun6i_vchan *vchan;
 458        struct sun6i_pchan *pchan;
 459        int i, j, ret = IRQ_NONE;
 460        u32 status;
 461
 462        for (i = 0; i < sdev->cfg->nr_max_channels / DMA_IRQ_CHAN_NR; i++) {
 463                status = readl(sdev->base + DMA_IRQ_STAT(i));
 464                if (!status)
 465                        continue;
 466
 467                dev_dbg(sdev->slave.dev, "DMA irq status %s: 0x%x\n",
 468                        i ? "high" : "low", status);
 469
 470                writel(status, sdev->base + DMA_IRQ_STAT(i));
 471
 472                for (j = 0; (j < DMA_IRQ_CHAN_NR) && status; j++) {
 473                        pchan = sdev->pchans + j;
 474                        vchan = pchan->vchan;
 475                        if (vchan && (status & vchan->irq_type)) {
 476                                if (vchan->cyclic) {
 477                                        vchan_cyclic_callback(&pchan->desc->vd);
 478                                } else {
 479                                        spin_lock(&vchan->vc.lock);
 480                                        vchan_cookie_complete(&pchan->desc->vd);
 481                                        pchan->done = pchan->desc;
 482                                        spin_unlock(&vchan->vc.lock);
 483                                }
 484                        }
 485
 486                        status = status >> DMA_IRQ_CHAN_WIDTH;
 487                }
 488
 489                if (!atomic_read(&sdev->tasklet_shutdown))
 490                        tasklet_schedule(&sdev->task);
 491                ret = IRQ_HANDLED;
 492        }
 493
 494        return ret;
 495}
 496
 497static int set_config(struct sun6i_dma_dev *sdev,
 498                        struct dma_slave_config *sconfig,
 499                        enum dma_transfer_direction direction,
 500                        u32 *p_cfg)
 501{
 502        s8 src_width, dst_width, src_burst, dst_burst;
 503
 504        switch (direction) {
 505        case DMA_MEM_TO_DEV:
 506                src_burst = convert_burst(sconfig->src_maxburst ?
 507                                        sconfig->src_maxburst : 8);
 508                src_width = convert_buswidth(sconfig->src_addr_width !=
 509                                                DMA_SLAVE_BUSWIDTH_UNDEFINED ?
 510                                sconfig->src_addr_width :
 511                                DMA_SLAVE_BUSWIDTH_4_BYTES);
 512                dst_burst = convert_burst(sconfig->dst_maxburst);
 513                dst_width = convert_buswidth(sconfig->dst_addr_width);
 514                break;
 515        case DMA_DEV_TO_MEM:
 516                src_burst = convert_burst(sconfig->src_maxburst);
 517                src_width = convert_buswidth(sconfig->src_addr_width);
 518                dst_burst = convert_burst(sconfig->dst_maxburst ?
 519                                        sconfig->dst_maxburst : 8);
 520                dst_width = convert_buswidth(sconfig->dst_addr_width !=
 521                                                DMA_SLAVE_BUSWIDTH_UNDEFINED ?
 522                                sconfig->dst_addr_width :
 523                                DMA_SLAVE_BUSWIDTH_4_BYTES);
 524                break;
 525        default:
 526                return -EINVAL;
 527        }
 528
 529        if (src_burst < 0)
 530                return src_burst;
 531        if (src_width < 0)
 532                return src_width;
 533        if (dst_burst < 0)
 534                return dst_burst;
 535        if (dst_width < 0)
 536                return dst_width;
 537
 538        *p_cfg = DMA_CHAN_CFG_SRC_BURST(src_burst) |
 539                DMA_CHAN_CFG_SRC_WIDTH(src_width) |
 540                DMA_CHAN_CFG_DST_BURST(dst_burst) |
 541                DMA_CHAN_CFG_DST_WIDTH(dst_width);
 542
 543        return 0;
 544}
 545
 546static struct dma_async_tx_descriptor *sun6i_dma_prep_dma_memcpy(
 547                struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
 548                size_t len, unsigned long flags)
 549{
 550        struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(chan->device);
 551        struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
 552        struct sun6i_dma_lli *v_lli;
 553        struct sun6i_desc *txd;
 554        dma_addr_t p_lli;
 555        s8 burst, width;
 556
 557        dev_dbg(chan2dev(chan),
 558                "%s; chan: %d, dest: %pad, src: %pad, len: %zu. flags: 0x%08lx\n",
 559                __func__, vchan->vc.chan.chan_id, &dest, &src, len, flags);
 560
 561        if (!len)
 562                return NULL;
 563
 564        txd = kzalloc(sizeof(*txd), GFP_NOWAIT);
 565        if (!txd)
 566                return NULL;
 567
 568        v_lli = dma_pool_alloc(sdev->pool, GFP_NOWAIT, &p_lli);
 569        if (!v_lli) {
 570                dev_err(sdev->slave.dev, "Failed to alloc lli memory\n");
 571                goto err_txd_free;
 572        }
 573
 574        v_lli->src = src;
 575        v_lli->dst = dest;
 576        v_lli->len = len;
 577        v_lli->para = NORMAL_WAIT;
 578
 579        burst = convert_burst(8);
 580        width = convert_buswidth(DMA_SLAVE_BUSWIDTH_4_BYTES);
 581        v_lli->cfg = DMA_CHAN_CFG_SRC_DRQ(DRQ_SDRAM) |
 582                DMA_CHAN_CFG_DST_DRQ(DRQ_SDRAM) |
 583                DMA_CHAN_CFG_DST_LINEAR_MODE |
 584                DMA_CHAN_CFG_SRC_LINEAR_MODE |
 585                DMA_CHAN_CFG_SRC_BURST(burst) |
 586                DMA_CHAN_CFG_SRC_WIDTH(width) |
 587                DMA_CHAN_CFG_DST_BURST(burst) |
 588                DMA_CHAN_CFG_DST_WIDTH(width);
 589
 590        sun6i_dma_lli_add(NULL, v_lli, p_lli, txd);
 591
 592        sun6i_dma_dump_lli(vchan, v_lli);
 593
 594        return vchan_tx_prep(&vchan->vc, &txd->vd, flags);
 595
 596err_txd_free:
 597        kfree(txd);
 598        return NULL;
 599}
 600
 601static struct dma_async_tx_descriptor *sun6i_dma_prep_slave_sg(
 602                struct dma_chan *chan, struct scatterlist *sgl,
 603                unsigned int sg_len, enum dma_transfer_direction dir,
 604                unsigned long flags, void *context)
 605{
 606        struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(chan->device);
 607        struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
 608        struct dma_slave_config *sconfig = &vchan->cfg;
 609        struct sun6i_dma_lli *v_lli, *prev = NULL;
 610        struct sun6i_desc *txd;
 611        struct scatterlist *sg;
 612        dma_addr_t p_lli;
 613        u32 lli_cfg;
 614        int i, ret;
 615
 616        if (!sgl)
 617                return NULL;
 618
 619        ret = set_config(sdev, sconfig, dir, &lli_cfg);
 620        if (ret) {
 621                dev_err(chan2dev(chan), "Invalid DMA configuration\n");
 622                return NULL;
 623        }
 624
 625        txd = kzalloc(sizeof(*txd), GFP_NOWAIT);
 626        if (!txd)
 627                return NULL;
 628
 629        for_each_sg(sgl, sg, sg_len, i) {
 630                v_lli = dma_pool_alloc(sdev->pool, GFP_NOWAIT, &p_lli);
 631                if (!v_lli)
 632                        goto err_lli_free;
 633
 634                v_lli->len = sg_dma_len(sg);
 635                v_lli->para = NORMAL_WAIT;
 636
 637                if (dir == DMA_MEM_TO_DEV) {
 638                        v_lli->src = sg_dma_address(sg);
 639                        v_lli->dst = sconfig->dst_addr;
 640                        v_lli->cfg = lli_cfg |
 641                                DMA_CHAN_CFG_DST_IO_MODE |
 642                                DMA_CHAN_CFG_SRC_LINEAR_MODE |
 643                                DMA_CHAN_CFG_SRC_DRQ(DRQ_SDRAM) |
 644                                DMA_CHAN_CFG_DST_DRQ(vchan->port);
 645
 646                        dev_dbg(chan2dev(chan),
 647                                "%s; chan: %d, dest: %pad, src: %pad, len: %u. flags: 0x%08lx\n",
 648                                __func__, vchan->vc.chan.chan_id,
 649                                &sconfig->dst_addr, &sg_dma_address(sg),
 650                                sg_dma_len(sg), flags);
 651
 652                } else {
 653                        v_lli->src = sconfig->src_addr;
 654                        v_lli->dst = sg_dma_address(sg);
 655                        v_lli->cfg = lli_cfg |
 656                                DMA_CHAN_CFG_DST_LINEAR_MODE |
 657                                DMA_CHAN_CFG_SRC_IO_MODE |
 658                                DMA_CHAN_CFG_DST_DRQ(DRQ_SDRAM) |
 659                                DMA_CHAN_CFG_SRC_DRQ(vchan->port);
 660
 661                        dev_dbg(chan2dev(chan),
 662                                "%s; chan: %d, dest: %pad, src: %pad, len: %u. flags: 0x%08lx\n",
 663                                __func__, vchan->vc.chan.chan_id,
 664                                &sg_dma_address(sg), &sconfig->src_addr,
 665                                sg_dma_len(sg), flags);
 666                }
 667
 668                prev = sun6i_dma_lli_add(prev, v_lli, p_lli, txd);
 669        }
 670
 671        dev_dbg(chan2dev(chan), "First: %pad\n", &txd->p_lli);
 672        for (prev = txd->v_lli; prev; prev = prev->v_lli_next)
 673                sun6i_dma_dump_lli(vchan, prev);
 674
 675        return vchan_tx_prep(&vchan->vc, &txd->vd, flags);
 676
 677err_lli_free:
 678        for (prev = txd->v_lli; prev; prev = prev->v_lli_next)
 679                dma_pool_free(sdev->pool, prev, virt_to_phys(prev));
 680        kfree(txd);
 681        return NULL;
 682}
 683
 684static struct dma_async_tx_descriptor *sun6i_dma_prep_dma_cyclic(
 685                                        struct dma_chan *chan,
 686                                        dma_addr_t buf_addr,
 687                                        size_t buf_len,
 688                                        size_t period_len,
 689                                        enum dma_transfer_direction dir,
 690                                        unsigned long flags)
 691{
 692        struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(chan->device);
 693        struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
 694        struct dma_slave_config *sconfig = &vchan->cfg;
 695        struct sun6i_dma_lli *v_lli, *prev = NULL;
 696        struct sun6i_desc *txd;
 697        dma_addr_t p_lli;
 698        u32 lli_cfg;
 699        unsigned int i, periods = buf_len / period_len;
 700        int ret;
 701
 702        ret = set_config(sdev, sconfig, dir, &lli_cfg);
 703        if (ret) {
 704                dev_err(chan2dev(chan), "Invalid DMA configuration\n");
 705                return NULL;
 706        }
 707
 708        txd = kzalloc(sizeof(*txd), GFP_NOWAIT);
 709        if (!txd)
 710                return NULL;
 711
 712        for (i = 0; i < periods; i++) {
 713                v_lli = dma_pool_alloc(sdev->pool, GFP_NOWAIT, &p_lli);
 714                if (!v_lli) {
 715                        dev_err(sdev->slave.dev, "Failed to alloc lli memory\n");
 716                        goto err_lli_free;
 717                }
 718
 719                v_lli->len = period_len;
 720                v_lli->para = NORMAL_WAIT;
 721
 722                if (dir == DMA_MEM_TO_DEV) {
 723                        v_lli->src = buf_addr + period_len * i;
 724                        v_lli->dst = sconfig->dst_addr;
 725                        v_lli->cfg = lli_cfg |
 726                                DMA_CHAN_CFG_DST_IO_MODE |
 727                                DMA_CHAN_CFG_SRC_LINEAR_MODE |
 728                                DMA_CHAN_CFG_SRC_DRQ(DRQ_SDRAM) |
 729                                DMA_CHAN_CFG_DST_DRQ(vchan->port);
 730                } else {
 731                        v_lli->src = sconfig->src_addr;
 732                        v_lli->dst = buf_addr + period_len * i;
 733                        v_lli->cfg = lli_cfg |
 734                                DMA_CHAN_CFG_DST_LINEAR_MODE |
 735                                DMA_CHAN_CFG_SRC_IO_MODE |
 736                                DMA_CHAN_CFG_DST_DRQ(DRQ_SDRAM) |
 737                                DMA_CHAN_CFG_SRC_DRQ(vchan->port);
 738                }
 739
 740                prev = sun6i_dma_lli_add(prev, v_lli, p_lli, txd);
 741        }
 742
 743        prev->p_lli_next = txd->p_lli;          /* cyclic list */
 744
 745        vchan->cyclic = true;
 746
 747        return vchan_tx_prep(&vchan->vc, &txd->vd, flags);
 748
 749err_lli_free:
 750        for (prev = txd->v_lli; prev; prev = prev->v_lli_next)
 751                dma_pool_free(sdev->pool, prev, virt_to_phys(prev));
 752        kfree(txd);
 753        return NULL;
 754}
 755
 756static int sun6i_dma_config(struct dma_chan *chan,
 757                            struct dma_slave_config *config)
 758{
 759        struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
 760
 761        memcpy(&vchan->cfg, config, sizeof(*config));
 762
 763        return 0;
 764}
 765
 766static int sun6i_dma_pause(struct dma_chan *chan)
 767{
 768        struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(chan->device);
 769        struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
 770        struct sun6i_pchan *pchan = vchan->phy;
 771
 772        dev_dbg(chan2dev(chan), "vchan %p: pause\n", &vchan->vc);
 773
 774        if (pchan) {
 775                writel(DMA_CHAN_PAUSE_PAUSE,
 776                       pchan->base + DMA_CHAN_PAUSE);
 777        } else {
 778                spin_lock(&sdev->lock);
 779                list_del_init(&vchan->node);
 780                spin_unlock(&sdev->lock);
 781        }
 782
 783        return 0;
 784}
 785
 786static int sun6i_dma_resume(struct dma_chan *chan)
 787{
 788        struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(chan->device);
 789        struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
 790        struct sun6i_pchan *pchan = vchan->phy;
 791        unsigned long flags;
 792
 793        dev_dbg(chan2dev(chan), "vchan %p: resume\n", &vchan->vc);
 794
 795        spin_lock_irqsave(&vchan->vc.lock, flags);
 796
 797        if (pchan) {
 798                writel(DMA_CHAN_PAUSE_RESUME,
 799                       pchan->base + DMA_CHAN_PAUSE);
 800        } else if (!list_empty(&vchan->vc.desc_issued)) {
 801                spin_lock(&sdev->lock);
 802                list_add_tail(&vchan->node, &sdev->pending);
 803                spin_unlock(&sdev->lock);
 804        }
 805
 806        spin_unlock_irqrestore(&vchan->vc.lock, flags);
 807
 808        return 0;
 809}
 810
 811static int sun6i_dma_terminate_all(struct dma_chan *chan)
 812{
 813        struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(chan->device);
 814        struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
 815        struct sun6i_pchan *pchan = vchan->phy;
 816        unsigned long flags;
 817        LIST_HEAD(head);
 818
 819        spin_lock(&sdev->lock);
 820        list_del_init(&vchan->node);
 821        spin_unlock(&sdev->lock);
 822
 823        spin_lock_irqsave(&vchan->vc.lock, flags);
 824
 825        if (vchan->cyclic) {
 826                vchan->cyclic = false;
 827                if (pchan && pchan->desc) {
 828                        struct virt_dma_desc *vd = &pchan->desc->vd;
 829                        struct virt_dma_chan *vc = &vchan->vc;
 830
 831                        list_add_tail(&vd->node, &vc->desc_completed);
 832                }
 833        }
 834
 835        vchan_get_all_descriptors(&vchan->vc, &head);
 836
 837        if (pchan) {
 838                writel(DMA_CHAN_ENABLE_STOP, pchan->base + DMA_CHAN_ENABLE);
 839                writel(DMA_CHAN_PAUSE_RESUME, pchan->base + DMA_CHAN_PAUSE);
 840
 841                vchan->phy = NULL;
 842                pchan->vchan = NULL;
 843                pchan->desc = NULL;
 844                pchan->done = NULL;
 845        }
 846
 847        spin_unlock_irqrestore(&vchan->vc.lock, flags);
 848
 849        vchan_dma_desc_free_list(&vchan->vc, &head);
 850
 851        return 0;
 852}
 853
 854static enum dma_status sun6i_dma_tx_status(struct dma_chan *chan,
 855                                           dma_cookie_t cookie,
 856                                           struct dma_tx_state *state)
 857{
 858        struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
 859        struct sun6i_pchan *pchan = vchan->phy;
 860        struct sun6i_dma_lli *lli;
 861        struct virt_dma_desc *vd;
 862        struct sun6i_desc *txd;
 863        enum dma_status ret;
 864        unsigned long flags;
 865        size_t bytes = 0;
 866
 867        ret = dma_cookie_status(chan, cookie, state);
 868        if (ret == DMA_COMPLETE || !state)
 869                return ret;
 870
 871        spin_lock_irqsave(&vchan->vc.lock, flags);
 872
 873        vd = vchan_find_desc(&vchan->vc, cookie);
 874        txd = to_sun6i_desc(&vd->tx);
 875
 876        if (vd) {
 877                for (lli = txd->v_lli; lli != NULL; lli = lli->v_lli_next)
 878                        bytes += lli->len;
 879        } else if (!pchan || !pchan->desc) {
 880                bytes = 0;
 881        } else {
 882                bytes = sun6i_get_chan_size(pchan);
 883        }
 884
 885        spin_unlock_irqrestore(&vchan->vc.lock, flags);
 886
 887        dma_set_residue(state, bytes);
 888
 889        return ret;
 890}
 891
 892static void sun6i_dma_issue_pending(struct dma_chan *chan)
 893{
 894        struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(chan->device);
 895        struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
 896        unsigned long flags;
 897
 898        spin_lock_irqsave(&vchan->vc.lock, flags);
 899
 900        if (vchan_issue_pending(&vchan->vc)) {
 901                spin_lock(&sdev->lock);
 902
 903                if (!vchan->phy && list_empty(&vchan->node)) {
 904                        list_add_tail(&vchan->node, &sdev->pending);
 905                        tasklet_schedule(&sdev->task);
 906                        dev_dbg(chan2dev(chan), "vchan %p: issued\n",
 907                                &vchan->vc);
 908                }
 909
 910                spin_unlock(&sdev->lock);
 911        } else {
 912                dev_dbg(chan2dev(chan), "vchan %p: nothing to issue\n",
 913                        &vchan->vc);
 914        }
 915
 916        spin_unlock_irqrestore(&vchan->vc.lock, flags);
 917}
 918
 919static void sun6i_dma_free_chan_resources(struct dma_chan *chan)
 920{
 921        struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(chan->device);
 922        struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
 923        unsigned long flags;
 924
 925        spin_lock_irqsave(&sdev->lock, flags);
 926        list_del_init(&vchan->node);
 927        spin_unlock_irqrestore(&sdev->lock, flags);
 928
 929        vchan_free_chan_resources(&vchan->vc);
 930}
 931
 932static struct dma_chan *sun6i_dma_of_xlate(struct of_phandle_args *dma_spec,
 933                                           struct of_dma *ofdma)
 934{
 935        struct sun6i_dma_dev *sdev = ofdma->of_dma_data;
 936        struct sun6i_vchan *vchan;
 937        struct dma_chan *chan;
 938        u8 port = dma_spec->args[0];
 939
 940        if (port > sdev->cfg->nr_max_requests)
 941                return NULL;
 942
 943        chan = dma_get_any_slave_channel(&sdev->slave);
 944        if (!chan)
 945                return NULL;
 946
 947        vchan = to_sun6i_vchan(chan);
 948        vchan->port = port;
 949
 950        return chan;
 951}
 952
 953static inline void sun6i_kill_tasklet(struct sun6i_dma_dev *sdev)
 954{
 955        /* Disable all interrupts from DMA */
 956        writel(0, sdev->base + DMA_IRQ_EN(0));
 957        writel(0, sdev->base + DMA_IRQ_EN(1));
 958
 959        /* Prevent spurious interrupts from scheduling the tasklet */
 960        atomic_inc(&sdev->tasklet_shutdown);
 961
 962        /* Make sure we won't have any further interrupts */
 963        devm_free_irq(sdev->slave.dev, sdev->irq, sdev);
 964
 965        /* Actually prevent the tasklet from being scheduled */
 966        tasklet_kill(&sdev->task);
 967}
 968
 969static inline void sun6i_dma_free(struct sun6i_dma_dev *sdev)
 970{
 971        int i;
 972
 973        for (i = 0; i < sdev->cfg->nr_max_vchans; i++) {
 974                struct sun6i_vchan *vchan = &sdev->vchans[i];
 975
 976                list_del(&vchan->vc.chan.device_node);
 977                tasklet_kill(&vchan->vc.task);
 978        }
 979}
 980
 981/*
 982 * For A31:
 983 *
 984 * There's 16 physical channels that can work in parallel.
 985 *
 986 * However we have 30 different endpoints for our requests.
 987 *
 988 * Since the channels are able to handle only an unidirectional
 989 * transfer, we need to allocate more virtual channels so that
 990 * everyone can grab one channel.
 991 *
 992 * Some devices can't work in both direction (mostly because it
 993 * wouldn't make sense), so we have a bit fewer virtual channels than
 994 * 2 channels per endpoints.
 995 */
 996
 997static struct sun6i_dma_config sun6i_a31_dma_cfg = {
 998        .nr_max_channels = 16,
 999        .nr_max_requests = 30,
1000        .nr_max_vchans   = 53,
1001};
1002
1003/*
1004 * The A23 only has 8 physical channels, a maximum DRQ port id of 24,
1005 * and a total of 37 usable source and destination endpoints.
1006 */
1007
1008static struct sun6i_dma_config sun8i_a23_dma_cfg = {
1009        .nr_max_channels = 8,
1010        .nr_max_requests = 24,
1011        .nr_max_vchans   = 37,
1012};
1013
1014static struct sun6i_dma_config sun8i_a83t_dma_cfg = {
1015        .nr_max_channels = 8,
1016        .nr_max_requests = 28,
1017        .nr_max_vchans   = 39,
1018};
1019
1020/*
1021 * The H3 has 12 physical channels, a maximum DRQ port id of 27,
1022 * and a total of 34 usable source and destination endpoints.
1023 */
1024
1025static struct sun6i_dma_config sun8i_h3_dma_cfg = {
1026        .nr_max_channels = 12,
1027        .nr_max_requests = 27,
1028        .nr_max_vchans   = 34,
1029};
1030
1031static const struct of_device_id sun6i_dma_match[] = {
1032        { .compatible = "allwinner,sun6i-a31-dma", .data = &sun6i_a31_dma_cfg },
1033        { .compatible = "allwinner,sun8i-a23-dma", .data = &sun8i_a23_dma_cfg },
1034        { .compatible = "allwinner,sun8i-a83t-dma", .data = &sun8i_a83t_dma_cfg },
1035        { .compatible = "allwinner,sun8i-h3-dma", .data = &sun8i_h3_dma_cfg },
1036        { /* sentinel */ }
1037};
1038MODULE_DEVICE_TABLE(of, sun6i_dma_match);
1039
1040static int sun6i_dma_probe(struct platform_device *pdev)
1041{
1042        const struct of_device_id *device;
1043        struct sun6i_dma_dev *sdc;
1044        struct resource *res;
1045        int ret, i;
1046
1047        sdc = devm_kzalloc(&pdev->dev, sizeof(*sdc), GFP_KERNEL);
1048        if (!sdc)
1049                return -ENOMEM;
1050
1051        device = of_match_device(sun6i_dma_match, &pdev->dev);
1052        if (!device)
1053                return -ENODEV;
1054        sdc->cfg = device->data;
1055
1056        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1057        sdc->base = devm_ioremap_resource(&pdev->dev, res);
1058        if (IS_ERR(sdc->base))
1059                return PTR_ERR(sdc->base);
1060
1061        sdc->irq = platform_get_irq(pdev, 0);
1062        if (sdc->irq < 0) {
1063                dev_err(&pdev->dev, "Cannot claim IRQ\n");
1064                return sdc->irq;
1065        }
1066
1067        sdc->clk = devm_clk_get(&pdev->dev, NULL);
1068        if (IS_ERR(sdc->clk)) {
1069                dev_err(&pdev->dev, "No clock specified\n");
1070                return PTR_ERR(sdc->clk);
1071        }
1072
1073        sdc->rstc = devm_reset_control_get(&pdev->dev, NULL);
1074        if (IS_ERR(sdc->rstc)) {
1075                dev_err(&pdev->dev, "No reset controller specified\n");
1076                return PTR_ERR(sdc->rstc);
1077        }
1078
1079        sdc->pool = dmam_pool_create(dev_name(&pdev->dev), &pdev->dev,
1080                                     sizeof(struct sun6i_dma_lli), 4, 0);
1081        if (!sdc->pool) {
1082                dev_err(&pdev->dev, "No memory for descriptors dma pool\n");
1083                return -ENOMEM;
1084        }
1085
1086        platform_set_drvdata(pdev, sdc);
1087        INIT_LIST_HEAD(&sdc->pending);
1088        spin_lock_init(&sdc->lock);
1089
1090        dma_cap_set(DMA_PRIVATE, sdc->slave.cap_mask);
1091        dma_cap_set(DMA_MEMCPY, sdc->slave.cap_mask);
1092        dma_cap_set(DMA_SLAVE, sdc->slave.cap_mask);
1093        dma_cap_set(DMA_CYCLIC, sdc->slave.cap_mask);
1094
1095        INIT_LIST_HEAD(&sdc->slave.channels);
1096        sdc->slave.device_free_chan_resources   = sun6i_dma_free_chan_resources;
1097        sdc->slave.device_tx_status             = sun6i_dma_tx_status;
1098        sdc->slave.device_issue_pending         = sun6i_dma_issue_pending;
1099        sdc->slave.device_prep_slave_sg         = sun6i_dma_prep_slave_sg;
1100        sdc->slave.device_prep_dma_memcpy       = sun6i_dma_prep_dma_memcpy;
1101        sdc->slave.device_prep_dma_cyclic       = sun6i_dma_prep_dma_cyclic;
1102        sdc->slave.copy_align                   = DMAENGINE_ALIGN_4_BYTES;
1103        sdc->slave.device_config                = sun6i_dma_config;
1104        sdc->slave.device_pause                 = sun6i_dma_pause;
1105        sdc->slave.device_resume                = sun6i_dma_resume;
1106        sdc->slave.device_terminate_all         = sun6i_dma_terminate_all;
1107        sdc->slave.src_addr_widths              = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
1108                                                  BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
1109                                                  BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
1110        sdc->slave.dst_addr_widths              = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
1111                                                  BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
1112                                                  BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
1113        sdc->slave.directions                   = BIT(DMA_DEV_TO_MEM) |
1114                                                  BIT(DMA_MEM_TO_DEV);
1115        sdc->slave.residue_granularity          = DMA_RESIDUE_GRANULARITY_BURST;
1116        sdc->slave.dev = &pdev->dev;
1117
1118        sdc->pchans = devm_kcalloc(&pdev->dev, sdc->cfg->nr_max_channels,
1119                                   sizeof(struct sun6i_pchan), GFP_KERNEL);
1120        if (!sdc->pchans)
1121                return -ENOMEM;
1122
1123        sdc->vchans = devm_kcalloc(&pdev->dev, sdc->cfg->nr_max_vchans,
1124                                   sizeof(struct sun6i_vchan), GFP_KERNEL);
1125        if (!sdc->vchans)
1126                return -ENOMEM;
1127
1128        tasklet_init(&sdc->task, sun6i_dma_tasklet, (unsigned long)sdc);
1129
1130        for (i = 0; i < sdc->cfg->nr_max_channels; i++) {
1131                struct sun6i_pchan *pchan = &sdc->pchans[i];
1132
1133                pchan->idx = i;
1134                pchan->base = sdc->base + 0x100 + i * 0x40;
1135        }
1136
1137        for (i = 0; i < sdc->cfg->nr_max_vchans; i++) {
1138                struct sun6i_vchan *vchan = &sdc->vchans[i];
1139
1140                INIT_LIST_HEAD(&vchan->node);
1141                vchan->vc.desc_free = sun6i_dma_free_desc;
1142                vchan_init(&vchan->vc, &sdc->slave);
1143        }
1144
1145        ret = reset_control_deassert(sdc->rstc);
1146        if (ret) {
1147                dev_err(&pdev->dev, "Couldn't deassert the device from reset\n");
1148                goto err_chan_free;
1149        }
1150
1151        ret = clk_prepare_enable(sdc->clk);
1152        if (ret) {
1153                dev_err(&pdev->dev, "Couldn't enable the clock\n");
1154                goto err_reset_assert;
1155        }
1156
1157        ret = devm_request_irq(&pdev->dev, sdc->irq, sun6i_dma_interrupt, 0,
1158                               dev_name(&pdev->dev), sdc);
1159        if (ret) {
1160                dev_err(&pdev->dev, "Cannot request IRQ\n");
1161                goto err_clk_disable;
1162        }
1163
1164        ret = dma_async_device_register(&sdc->slave);
1165        if (ret) {
1166                dev_warn(&pdev->dev, "Failed to register DMA engine device\n");
1167                goto err_irq_disable;
1168        }
1169
1170        ret = of_dma_controller_register(pdev->dev.of_node, sun6i_dma_of_xlate,
1171                                         sdc);
1172        if (ret) {
1173                dev_err(&pdev->dev, "of_dma_controller_register failed\n");
1174                goto err_dma_unregister;
1175        }
1176
1177        /*
1178         * sun8i variant requires us to toggle a dma gating register,
1179         * as seen in Allwinner's SDK. This register is not documented
1180         * in the A23 user manual.
1181         */
1182        if (of_device_is_compatible(pdev->dev.of_node,
1183                                    "allwinner,sun8i-a23-dma"))
1184                writel(SUN8I_DMA_GATE_ENABLE, sdc->base + SUN8I_DMA_GATE);
1185
1186        return 0;
1187
1188err_dma_unregister:
1189        dma_async_device_unregister(&sdc->slave);
1190err_irq_disable:
1191        sun6i_kill_tasklet(sdc);
1192err_clk_disable:
1193        clk_disable_unprepare(sdc->clk);
1194err_reset_assert:
1195        reset_control_assert(sdc->rstc);
1196err_chan_free:
1197        sun6i_dma_free(sdc);
1198        return ret;
1199}
1200
1201static int sun6i_dma_remove(struct platform_device *pdev)
1202{
1203        struct sun6i_dma_dev *sdc = platform_get_drvdata(pdev);
1204
1205        of_dma_controller_free(pdev->dev.of_node);
1206        dma_async_device_unregister(&sdc->slave);
1207
1208        sun6i_kill_tasklet(sdc);
1209
1210        clk_disable_unprepare(sdc->clk);
1211        reset_control_assert(sdc->rstc);
1212
1213        sun6i_dma_free(sdc);
1214
1215        return 0;
1216}
1217
1218static struct platform_driver sun6i_dma_driver = {
1219        .probe          = sun6i_dma_probe,
1220        .remove         = sun6i_dma_remove,
1221        .driver = {
1222                .name           = "sun6i-dma",
1223                .of_match_table = sun6i_dma_match,
1224        },
1225};
1226module_platform_driver(sun6i_dma_driver);
1227
1228MODULE_DESCRIPTION("Allwinner A31 DMA Controller Driver");
1229MODULE_AUTHOR("Sugar <shuge@allwinnertech.com>");
1230MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
1231MODULE_LICENSE("GPL");
1232