drivers/dma/dma-axi-dmac.c

   1 /*
   2  * Driver for the Analog Devices AXI-DMAC core
   3  *
   4  * Copyright 2013-2015 Analog Devices Inc.
   5  *  Author: Lars-Peter Clausen <lars@metafoo.de>
   6  *
   7  * Licensed under the GPL-2.
   8  */
   9
  10 #include <linux/clk.h>
  11 #include <linux/device.h>
  12 #include <linux/dma-mapping.h>
  13 #include <linux/dmaengine.h>
  14 #include <linux/err.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/io.h>
  17 #include <linux/kernel.h>
  18 #include <linux/module.h>
  19 #include <linux/of.h>
  20 #include <linux/of_dma.h>
  21 #include <linux/platform_device.h>
  22 #include <linux/slab.h>
  23
  24 #include <dt-bindings/dma/axi-dmac.h>
  25
  26 #include "dmaengine.h"
  27 #include "virt-dma.h"
  28
  29 /*
  30  * The AXI-DMAC is a soft IP core that is used in FPGA designs. The core has
  31  * various instantiation parameters which decided the exact feature set support
  32  * by the core.
  33  *
  34  * Each channel of the core has a source interface and a destination interface.
  35  * The number of channels and the type of the channel interfaces is selected at
  36  * configuration time. A interface can either be a connected to a central memory
  37  * interconnect, which allows access to system memory, or it can be connected to
  38  * a dedicated bus which is directly connected to a data port on a peripheral.
  39  * Given that those are configuration options of the core that are selected when
  40  * it is instantiated this means that they can not be changed by software at
  41  * runtime. By extension this means that each channel is uni-directional. It can
  42  * either be device to memory or memory to device, but not both. Also since the
  43  * device side is a dedicated data bus only connected to a single peripheral
  44  * there is no address than can or needs to be configured for the device side.
  45  */
  46
  47 #define AXI_DMAC_REG_IRQ_MASK           0x80
  48 #define AXI_DMAC_REG_IRQ_PENDING        0x84
  49 #define AXI_DMAC_REG_IRQ_SOURCE         0x88
  50
  51 #define AXI_DMAC_REG_CTRL               0x400
  52 #define AXI_DMAC_REG_TRANSFER_ID        0x404
  53 #define AXI_DMAC_REG_START_TRANSFER     0x408
  54 #define AXI_DMAC_REG_FLAGS              0x40c
  55 #define AXI_DMAC_REG_DEST_ADDRESS       0x410
  56 #define AXI_DMAC_REG_SRC_ADDRESS        0x414
  57 #define AXI_DMAC_REG_X_LENGTH           0x418
  58 #define AXI_DMAC_REG_Y_LENGTH           0x41c
  59 #define AXI_DMAC_REG_DEST_STRIDE        0x420
  60 #define AXI_DMAC_REG_SRC_STRIDE         0x424
  61 #define AXI_DMAC_REG_TRANSFER_DONE      0x428
  62 #define AXI_DMAC_REG_ACTIVE_TRANSFER_ID 0x42c
  63 #define AXI_DMAC_REG_STATUS             0x430
  64 #define AXI_DMAC_REG_CURRENT_SRC_ADDR   0x434
  65 #define AXI_DMAC_REG_CURRENT_DEST_ADDR  0x438
  66
  67 #define AXI_DMAC_CTRL_ENABLE            BIT(0)
  68 #define AXI_DMAC_CTRL_PAUSE             BIT(1)
  69
  70 #define AXI_DMAC_IRQ_SOT                BIT(0)
  71 #define AXI_DMAC_IRQ_EOT                BIT(1)
  72
  73 #define AXI_DMAC_FLAG_CYCLIC            BIT(0)
  74
  75 /* The maximum ID allocated by the hardware is 31 */
  76 #define AXI_DMAC_SG_UNUSED 32U
  77
  78 struct axi_dmac_sg {
  79         dma_addr_t src_addr;
  80         dma_addr_t dest_addr;
  81         unsigned int x_len;
  82         unsigned int y_len;
  83         unsigned int dest_stride;
  84         unsigned int src_stride;
  85         unsigned int id;
  86         bool schedule_when_free;
  87 };
  88
  89 struct axi_dmac_desc {
  90         struct virt_dma_desc vdesc;
  91         bool cyclic;
  92
  93         unsigned int num_submitted;
  94         unsigned int num_completed;
  95         unsigned int num_sgs;
  96         struct axi_dmac_sg sg[];
  97 };
  98
  99 struct axi_dmac_chan {
 100         struct virt_dma_chan vchan;
 101
 102         struct axi_dmac_desc *next_desc;
 103         struct list_head active_descs;
 104         enum dma_transfer_direction direction;
 105
 106         unsigned int src_width;
 107         unsigned int dest_width;
 108         unsigned int src_type;
 109         unsigned int dest_type;
 110
 111         unsigned int max_length;
 112         unsigned int align_mask;
 113
 114         bool hw_cyclic;
 115         bool hw_2d;
 116 };
 117
 118 struct axi_dmac {
 119         void __iomem *base;
 120         int irq;
 121
 122         struct clk *clk;
 123
 124         struct dma_device dma_dev;
 125         struct axi_dmac_chan chan;
 126
 127         struct device_dma_parameters dma_parms;
 128 };
 129
 130 static struct axi_dmac *chan_to_axi_dmac(struct axi_dmac_chan *chan)
 131 {
 132         return container_of(chan->vchan.chan.device, struct axi_dmac,
 133                 dma_dev);
 134 }
 135
 136 static struct axi_dmac_chan *to_axi_dmac_chan(struct dma_chan *c)
 137 {
 138         return container_of(c, struct axi_dmac_chan, vchan.chan);
 139 }
 140
 141 static struct axi_dmac_desc *to_axi_dmac_desc(struct virt_dma_desc *vdesc)
 142 {
 143         return container_of(vdesc, struct axi_dmac_desc, vdesc);
 144 }
 145
 146 static void axi_dmac_write(struct axi_dmac *axi_dmac, unsigned int reg,
 147         unsigned int val)
 148 {
 149         writel(val, axi_dmac->base + reg);
 150 }
 151
 152 static int axi_dmac_read(struct axi_dmac *axi_dmac, unsigned int reg)
 153 {
 154         return readl(axi_dmac->base + reg);
 155 }
 156
 157 static int axi_dmac_src_is_mem(struct axi_dmac_chan *chan)
 158 {
 159         return chan->src_type == AXI_DMAC_BUS_TYPE_AXI_MM;
 160 }
 161
 162 static int axi_dmac_dest_is_mem(struct axi_dmac_chan *chan)
 163 {
 164         return chan->dest_type == AXI_DMAC_BUS_TYPE_AXI_MM;
 165 }
 166
 167 static bool axi_dmac_check_len(struct axi_dmac_chan *chan, unsigned int len)
 168 {
 169         if (len == 0 || len > chan->max_length)
 170                 return false;
 171         if ((len & chan->align_mask) != 0) /* Not aligned */
 172                 return false;
 173         return true;
 174 }
 175
 176 static bool axi_dmac_check_addr(struct axi_dmac_chan *chan, dma_addr_t addr)
 177 {
 178         if ((addr & chan->align_mask) != 0) /* Not aligned */
 179                 return false;
 180         return true;
 181 }
 182
 183 static void axi_dmac_start_transfer(struct axi_dmac_chan *chan)
 184 {
 185         struct axi_dmac *dmac = chan_to_axi_dmac(chan);
 186         struct virt_dma_desc *vdesc;
 187         struct axi_dmac_desc *desc;
 188         struct axi_dmac_sg *sg;
 189         unsigned int flags = 0;
 190         unsigned int val;
 191
 192         val = axi_dmac_read(dmac, AXI_DMAC_REG_START_TRANSFER);
 193         if (val) /* Queue is full, wait for the next SOT IRQ */
 194                 return;
 195
 196         desc = chan->next_desc;
 197
 198         if (!desc) {
 199                 vdesc = vchan_next_desc(&chan->vchan);
 200                 if (!vdesc)
 201                         return;
 202                 list_move_tail(&vdesc->node, &chan->active_descs);
 203                 desc = to_axi_dmac_desc(vdesc);
 204         }
 205         sg = &desc->sg[desc->num_submitted];
 206
 207         /* Already queued in cyclic mode. Wait for it to finish */
 208         if (sg->id != AXI_DMAC_SG_UNUSED) {
 209                 sg->schedule_when_free = true;
 210                 return;
 211         }
 212
 213         desc->num_submitted++;
 214         if (desc->num_submitted == desc->num_sgs) {
 215                 if (desc->cyclic)
 216                         desc->num_submitted = 0; /* Start again */
 217                 else
 218                         chan->next_desc = NULL;
 219         } else {
 220                 chan->next_desc = desc;
 221         }
 222
 223         sg->id = axi_dmac_read(dmac, AXI_DMAC_REG_TRANSFER_ID);
 224
 225         if (axi_dmac_dest_is_mem(chan)) {
 226                 axi_dmac_write(dmac, AXI_DMAC_REG_DEST_ADDRESS, sg->dest_addr);
 227                 axi_dmac_write(dmac, AXI_DMAC_REG_DEST_STRIDE, sg->dest_stride);
 228         }
 229
 230         if (axi_dmac_src_is_mem(chan)) {
 231                 axi_dmac_write(dmac, AXI_DMAC_REG_SRC_ADDRESS, sg->src_addr);
 232                 axi_dmac_write(dmac, AXI_DMAC_REG_SRC_STRIDE, sg->src_stride);
 233         }
 234
 235         /*
 236          * If the hardware supports cyclic transfers and there is no callback to
 237          * call and only a single segment, enable hw cyclic mode to avoid
 238          * unnecessary interrupts.
 239          */
 240         if (chan->hw_cyclic && desc->cyclic && !desc->vdesc.tx.callback &&
 241                 desc->num_sgs == 1)
 242                 flags |= AXI_DMAC_FLAG_CYCLIC;
 243
 244         axi_dmac_write(dmac, AXI_DMAC_REG_X_LENGTH, sg->x_len - 1);
 245         axi_dmac_write(dmac, AXI_DMAC_REG_Y_LENGTH, sg->y_len - 1);
 246         axi_dmac_write(dmac, AXI_DMAC_REG_FLAGS, flags);
 247         axi_dmac_write(dmac, AXI_DMAC_REG_START_TRANSFER, 1);
 248 }
 249
 250 static struct axi_dmac_desc *axi_dmac_active_desc(struct axi_dmac_chan *chan)
 251 {
 252         return list_first_entry_or_null(&chan->active_descs,
 253                 struct axi_dmac_desc, vdesc.node);
 254 }
 255
 256 static bool axi_dmac_transfer_done(struct axi_dmac_chan *chan,
 257         unsigned int completed_transfers)
 258 {
 259         struct axi_dmac_desc *active;
 260         struct axi_dmac_sg *sg;
 261         bool start_next = false;
 262
 263         active = axi_dmac_active_desc(chan);
 264         if (!active)
 265                 return false;
 266
 267         do {
 268                 sg = &active->sg[active->num_completed];
 269                 if (sg->id == AXI_DMAC_SG_UNUSED) /* Not yet submitted */
 270                         break;
 271                 if (!(BIT(sg->id) & completed_transfers))
 272                         break;
 273                 active->num_completed++;
 274                 sg->id = AXI_DMAC_SG_UNUSED;
 275                 if (sg->schedule_when_free) {
 276                         sg->schedule_when_free = false;
 277                         start_next = true;
 278                 }
 279
 280                 if (active->cyclic)
 281                         vchan_cyclic_callback(&active->vdesc);
 282
 283                 if (active->num_completed == active->num_sgs) {
 284                         if (active->cyclic) {
 285                                 active->num_completed = 0; /* wrap around */
 286                         } else {
 287                                 list_del(&active->vdesc.node);
 288                                 vchan_cookie_complete(&active->vdesc);
 289                                 active = axi_dmac_active_desc(chan);
 290                         }
 291                 }
 292         } while (active);
 293
 294         return start_next;
 295 }
 296
 297 static irqreturn_t axi_dmac_interrupt_handler(int irq, void *devid)
 298 {
 299         struct axi_dmac *dmac = devid;
 300         unsigned int pending;
 301         bool start_next = false;
 302
 303         pending = axi_dmac_read(dmac, AXI_DMAC_REG_IRQ_PENDING);
 304         if (!pending)
 305                 return IRQ_NONE;
 306
 307         axi_dmac_write(dmac, AXI_DMAC_REG_IRQ_PENDING, pending);
 308
 309         spin_lock(&dmac->chan.vchan.lock);
 310         /* One or more transfers have finished */
 311         if (pending & AXI_DMAC_IRQ_EOT) {
 312                 unsigned int completed;
 313
 314                 completed = axi_dmac_read(dmac, AXI_DMAC_REG_TRANSFER_DONE);
 315                 start_next = axi_dmac_transfer_done(&dmac->chan, completed);
 316         }
 317         /* Space has become available in the descriptor queue */
 318         if ((pending & AXI_DMAC_IRQ_SOT) || start_next)
 319                 axi_dmac_start_transfer(&dmac->chan);
 320         spin_unlock(&dmac->chan.vchan.lock);
 321
 322         return IRQ_HANDLED;
 323 }
 324
 325 static int axi_dmac_terminate_all(struct dma_chan *c)
 326 {
 327         struct axi_dmac_chan *chan = to_axi_dmac_chan(c);
 328         struct axi_dmac *dmac = chan_to_axi_dmac(chan);
 329         unsigned long flags;
 330         LIST_HEAD(head);
 331
 332         spin_lock_irqsave(&chan->vchan.lock, flags);
 333         axi_dmac_write(dmac, AXI_DMAC_REG_CTRL, 0);
 334         chan->next_desc = NULL;
 335         vchan_get_all_descriptors(&chan->vchan, &head);
 336         list_splice_tail_init(&chan->active_descs, &head);
 337         spin_unlock_irqrestore(&chan->vchan.lock, flags);
 338
 339         vchan_dma_desc_free_list(&chan->vchan, &head);
 340
 341         return 0;
 342 }
 343
 344 static void axi_dmac_synchronize(struct dma_chan *c)
 345 {
 346         struct axi_dmac_chan *chan = to_axi_dmac_chan(c);
 347
 348         vchan_synchronize(&chan->vchan);
 349 }
 350
 351 static void axi_dmac_issue_pending(struct dma_chan *c)
 352 {
 353         struct axi_dmac_chan *chan = to_axi_dmac_chan(c);
 354         struct axi_dmac *dmac = chan_to_axi_dmac(chan);
 355         unsigned long flags;
 356
 357         axi_dmac_write(dmac, AXI_DMAC_REG_CTRL, AXI_DMAC_CTRL_ENABLE);
 358
 359         spin_lock_irqsave(&chan->vchan.lock, flags);
 360         if (vchan_issue_pending(&chan->vchan))
 361                 axi_dmac_start_transfer(chan);
 362         spin_unlock_irqrestore(&chan->vchan.lock, flags);
 363 }
 364
 365 static struct axi_dmac_desc *axi_dmac_alloc_desc(unsigned int num_sgs)
 366 {
 367         struct axi_dmac_desc *desc;
 368         unsigned int i;
 369
 370         desc = kzalloc(sizeof(struct axi_dmac_desc) +
 371                 sizeof(struct axi_dmac_sg) * num_sgs, GFP_NOWAIT);
 372         if (!desc)
 373                 return NULL;
 374
 375         for (i = 0; i < num_sgs; i++)
 376                 desc->sg[i].id = AXI_DMAC_SG_UNUSED;
 377
 378         desc->num_sgs = num_sgs;
 379
 380         return desc;
 381 }
 382
 383 static struct dma_async_tx_descriptor *axi_dmac_prep_slave_sg(
 384         struct dma_chan *c, struct scatterlist *sgl,
 385         unsigned int sg_len, enum dma_transfer_direction direction,
 386         unsigned long flags, void *context)
 387 {
 388         struct axi_dmac_chan *chan = to_axi_dmac_chan(c);
 389         struct axi_dmac_desc *desc;
 390         struct scatterlist *sg;
 391         unsigned int i;
 392
 393         if (direction != chan->direction)
 394                 return NULL;
 395
 396         desc = axi_dmac_alloc_desc(sg_len);
 397         if (!desc)
 398                 return NULL;
 399
 400         for_each_sg(sgl, sg, sg_len, i) {
 401                 if (!axi_dmac_check_addr(chan, sg_dma_address(sg)) ||
 402                     !axi_dmac_check_len(chan, sg_dma_len(sg))) {
 403                         kfree(desc);
 404                         return NULL;
 405                 }
 406
 407                 if (direction == DMA_DEV_TO_MEM)
 408                         desc->sg[i].dest_addr = sg_dma_address(sg);
 409                 else
 410                         desc->sg[i].src_addr = sg_dma_address(sg);
 411                 desc->sg[i].x_len = sg_dma_len(sg);
 412                 desc->sg[i].y_len = 1;
 413         }
 414
 415         desc->cyclic = false;
 416
 417         return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
 418 }
 419
 420 static struct dma_async_tx_descriptor *axi_dmac_prep_dma_cyclic(
 421         struct dma_chan *c, dma_addr_t buf_addr, size_t buf_len,
 422         size_t period_len, enum dma_transfer_direction direction,
 423         unsigned long flags)
 424 {
 425         struct axi_dmac_chan *chan = to_axi_dmac_chan(c);
 426         struct axi_dmac_desc *desc;
 427         unsigned int num_periods, i;
 428
 429         if (direction != chan->direction)
 430                 return NULL;
 431
 432         if (!axi_dmac_check_len(chan, buf_len) ||
 433             !axi_dmac_check_addr(chan, buf_addr))
 434                 return NULL;
 435
 436         if (period_len == 0 || buf_len % period_len)
 437                 return NULL;
 438
 439         num_periods = buf_len / period_len;
 440
 441         desc = axi_dmac_alloc_desc(num_periods);
 442         if (!desc)
 443                 return NULL;
 444
 445         for (i = 0; i < num_periods; i++) {
 446                 if (direction == DMA_DEV_TO_MEM)
 447                         desc->sg[i].dest_addr = buf_addr;
 448                 else
 449                         desc->sg[i].src_addr = buf_addr;
 450                 desc->sg[i].x_len = period_len;
 451                 desc->sg[i].y_len = 1;
 452                 buf_addr += period_len;
 453         }
 454
 455         desc->cyclic = true;
 456
 457         return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
 458 }
 459
 460 static struct dma_async_tx_descriptor *axi_dmac_prep_interleaved(
 461         struct dma_chan *c, struct dma_interleaved_template *xt,
 462         unsigned long flags)
 463 {
 464         struct axi_dmac_chan *chan = to_axi_dmac_chan(c);
 465         struct axi_dmac_desc *desc;
 466         size_t dst_icg, src_icg;
 467
 468         if (xt->frame_size != 1)
 469                 return NULL;
 470
 471         if (xt->dir != chan->direction)
 472                 return NULL;
 473
 474         if (axi_dmac_src_is_mem(chan)) {
 475                 if (!xt->src_inc || !axi_dmac_check_addr(chan, xt->src_start))
 476                         return NULL;
 477         }
 478
 479         if (axi_dmac_dest_is_mem(chan)) {
 480                 if (!xt->dst_inc || !axi_dmac_check_addr(chan, xt->dst_start))
 481                         return NULL;
 482         }
 483
 484         dst_icg = dmaengine_get_dst_icg(xt, &xt->sgl[0]);
 485         src_icg = dmaengine_get_src_icg(xt, &xt->sgl[0]);
 486
 487         if (chan->hw_2d) {
 488                 if (!axi_dmac_check_len(chan, xt->sgl[0].size) ||
 489                     !axi_dmac_check_len(chan, xt->numf))
 490                         return NULL;
 491                 if (xt->sgl[0].size + dst_icg > chan->max_length ||
 492                     xt->sgl[0].size + src_icg > chan->max_length)
 493                         return NULL;
 494         } else {
 495                 if (dst_icg != 0 || src_icg != 0)
 496                         return NULL;
 497                 if (chan->max_length / xt->sgl[0].size < xt->numf)
 498                         return NULL;
 499                 if (!axi_dmac_check_len(chan, xt->sgl[0].size * xt->numf))
 500                         return NULL;
 501         }
 502
 503         desc = axi_dmac_alloc_desc(1);
 504         if (!desc)
 505                 return NULL;
 506
 507         if (axi_dmac_src_is_mem(chan)) {
 508                 desc->sg[0].src_addr = xt->src_start;
 509                 desc->sg[0].src_stride = xt->sgl[0].size + src_icg;
 510         }
 511
 512         if (axi_dmac_dest_is_mem(chan)) {
 513                 desc->sg[0].dest_addr = xt->dst_start;
 514                 desc->sg[0].dest_stride = xt->sgl[0].size + dst_icg;
 515         }
 516
 517         if (chan->hw_2d) {
 518                 desc->sg[0].x_len = xt->sgl[0].size;
 519                 desc->sg[0].y_len = xt->numf;
 520         } else {
 521                 desc->sg[0].x_len = xt->sgl[0].size * xt->numf;
 522                 desc->sg[0].y_len = 1;
 523         }
 524
 525         return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
 526 }
 527
 528 static void axi_dmac_free_chan_resources(struct dma_chan *c)
 529 {
 530         vchan_free_chan_resources(to_virt_chan(c));
 531 }
 532
 533 static void axi_dmac_desc_free(struct virt_dma_desc *vdesc)
 534 {
 535         kfree(container_of(vdesc, struct axi_dmac_desc, vdesc));
 536 }
 537
 538 /*
 539  * The configuration stored in the devicetree matches the configuration
 540  * parameters of the peripheral instance and allows the driver to know which
 541  * features are implemented and how it should behave.
 542  */
 543 static int axi_dmac_parse_chan_dt(struct device_node *of_chan,
 544         struct axi_dmac_chan *chan)
 545 {
 546         u32 val;
 547         int ret;
 548
 549         ret = of_property_read_u32(of_chan, "reg", &val);
 550         if (ret)
 551                 return ret;
 552
 553         /* We only support 1 channel for now */
 554         if (val != 0)
 555                 return -EINVAL;
 556
 557         ret = of_property_read_u32(of_chan, "adi,source-bus-type", &val);
 558         if (ret)
 559                 return ret;
 560         if (val > AXI_DMAC_BUS_TYPE_FIFO)
 561                 return -EINVAL;
 562         chan->src_type = val;
 563
 564         ret = of_property_read_u32(of_chan, "adi,destination-bus-type", &val);
 565         if (ret)
 566                 return ret;
 567         if (val > AXI_DMAC_BUS_TYPE_FIFO)
 568                 return -EINVAL;
 569         chan->dest_type = val;
 570
 571         ret = of_property_read_u32(of_chan, "adi,source-bus-width", &val);
 572         if (ret)
 573                 return ret;
 574         chan->src_width = val / 8;
 575
 576         ret = of_property_read_u32(of_chan, "adi,destination-bus-width", &val);
 577         if (ret)
 578                 return ret;
 579         chan->dest_width = val / 8;
 580
 581         ret = of_property_read_u32(of_chan, "adi,length-width", &val);
 582         if (ret)
 583                 return ret;
 584
 585         if (val >= 32)
 586                 chan->max_length = UINT_MAX;
 587         else
 588                 chan->max_length = (1ULL << val) - 1;
 589
 590         chan->align_mask = max(chan->dest_width, chan->src_width) - 1;
 591
 592         if (axi_dmac_dest_is_mem(chan) && axi_dmac_src_is_mem(chan))
 593                 chan->direction = DMA_MEM_TO_MEM;
 594         else if (!axi_dmac_dest_is_mem(chan) && axi_dmac_src_is_mem(chan))
 595                 chan->direction = DMA_MEM_TO_DEV;
 596         else if (axi_dmac_dest_is_mem(chan) && !axi_dmac_src_is_mem(chan))
 597                 chan->direction = DMA_DEV_TO_MEM;
 598         else
 599                 chan->direction = DMA_DEV_TO_DEV;
 600
 601         chan->hw_cyclic = of_property_read_bool(of_chan, "adi,cyclic");
 602         chan->hw_2d = of_property_read_bool(of_chan, "adi,2d");
 603
 604         return 0;
 605 }
 606
 607 static int axi_dmac_probe(struct platform_device *pdev)
 608 {
 609         struct device_node *of_channels, *of_chan;
 610         struct dma_device *dma_dev;
 611         struct axi_dmac *dmac;
 612         struct resource *res;
 613         int ret;
 614
 615         dmac = devm_kzalloc(&pdev->dev, sizeof(*dmac), GFP_KERNEL);
 616         if (!dmac)
 617                 return -ENOMEM;
 618
 619         dmac->irq = platform_get_irq(pdev, 0);
 620         if (dmac->irq < 0)
 621                 return dmac->irq;
 622         if (dmac->irq == 0)
 623                 return -EINVAL;
 624
 625         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 626         dmac->base = devm_ioremap_resource(&pdev->dev, res);
 627         if (IS_ERR(dmac->base))
 628                 return PTR_ERR(dmac->base);
 629
 630         dmac->clk = devm_clk_get(&pdev->dev, NULL);
 631         if (IS_ERR(dmac->clk))
 632                 return PTR_ERR(dmac->clk);
 633
 634         INIT_LIST_HEAD(&dmac->chan.active_descs);
 635
 636         of_channels = of_get_child_by_name(pdev->dev.of_node, "adi,channels");
 637         if (of_channels == NULL)
 638                 return -ENODEV;
 639
 640         for_each_child_of_node(of_channels, of_chan) {
 641                 ret = axi_dmac_parse_chan_dt(of_chan, &dmac->chan);
 642                 if (ret) {
 643                         of_node_put(of_chan);
 644                         of_node_put(of_channels);
 645                         return -EINVAL;
 646                 }
 647         }
 648         of_node_put(of_channels);
 649
 650         pdev->dev.dma_parms = &dmac->dma_parms;
 651         dma_set_max_seg_size(&pdev->dev, dmac->chan.max_length);
 652
 653         dma_dev = &dmac->dma_dev;
 654         dma_cap_set(DMA_SLAVE, dma_dev->cap_mask);
 655         dma_cap_set(DMA_CYCLIC, dma_dev->cap_mask);
 656         dma_dev->device_free_chan_resources = axi_dmac_free_chan_resources;
 657         dma_dev->device_tx_status = dma_cookie_status;
 658         dma_dev->device_issue_pending = axi_dmac_issue_pending;
 659         dma_dev->device_prep_slave_sg = axi_dmac_prep_slave_sg;
 660         dma_dev->device_prep_dma_cyclic = axi_dmac_prep_dma_cyclic;
 661         dma_dev->device_prep_interleaved_dma = axi_dmac_prep_interleaved;
 662         dma_dev->device_terminate_all = axi_dmac_terminate_all;
 663         dma_dev->device_synchronize = axi_dmac_synchronize;
 664         dma_dev->dev = &pdev->dev;
 665         dma_dev->chancnt = 1;
 666         dma_dev->src_addr_widths = BIT(dmac->chan.src_width);
 667         dma_dev->dst_addr_widths = BIT(dmac->chan.dest_width);
 668         dma_dev->directions = BIT(dmac->chan.direction);
 669         dma_dev->residue_granularity = DMA_RESIDUE_GRANULARITY_DESCRIPTOR;
 670         INIT_LIST_HEAD(&dma_dev->channels);
 671
 672         dmac->chan.vchan.desc_free = axi_dmac_desc_free;
 673         vchan_init(&dmac->chan.vchan, dma_dev);
 674
 675         ret = clk_prepare_enable(dmac->clk);
 676         if (ret < 0)
 677                 return ret;
 678
 679         axi_dmac_write(dmac, AXI_DMAC_REG_IRQ_MASK, 0x00);
 680
 681         ret = dma_async_device_register(dma_dev);
 682         if (ret)
 683                 goto err_clk_disable;
 684
 685         ret = of_dma_controller_register(pdev->dev.of_node,
 686                 of_dma_xlate_by_chan_id, dma_dev);
 687         if (ret)
 688                 goto err_unregister_device;
 689
 690         ret = request_irq(dmac->irq, axi_dmac_interrupt_handler, IRQF_SHARED,
 691                 dev_name(&pdev->dev), dmac);
 692         if (ret)
 693                 goto err_unregister_of;
 694
 695         platform_set_drvdata(pdev, dmac);
 696
 697         return 0;
 698
 699 err_unregister_of:
 700         of_dma_controller_free(pdev->dev.of_node);
 701 err_unregister_device:
 702         dma_async_device_unregister(&dmac->dma_dev);
 703 err_clk_disable:
 704         clk_disable_unprepare(dmac->clk);
 705
 706         return ret;
 707 }
 708
 709 static int axi_dmac_remove(struct platform_device *pdev)
 710 {
 711         struct axi_dmac *dmac = platform_get_drvdata(pdev);
 712
 713         of_dma_controller_free(pdev->dev.of_node);
 714         free_irq(dmac->irq, dmac);
 715         tasklet_kill(&dmac->chan.vchan.task);
 716         dma_async_device_unregister(&dmac->dma_dev);
 717         clk_disable_unprepare(dmac->clk);
 718
 719         return 0;
 720 }
 721
 722 static const struct of_device_id axi_dmac_of_match_table[] = {
 723         { .compatible = "adi,axi-dmac-1.00.a" },
 724         { },
 725 };
 726 MODULE_DEVICE_TABLE(of, axi_dmac_of_match_table);
 727
 728 static struct platform_driver axi_dmac_driver = {
 729         .driver = {
 730                 .name = "dma-axi-dmac",
 731                 .of_match_table = axi_dmac_of_match_table,
 732         },
 733         .probe = axi_dmac_probe,
 734         .remove = axi_dmac_remove,
 735 };
 736 module_platform_driver(axi_dmac_driver);
 737
 738 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 739 MODULE_DESCRIPTION("DMA controller driver for the AXI-DMAC controller");
 740 MODULE_LICENSE("GPL v2");