linux/drivers/dma/edma.c
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   1/*
   2 * TI EDMA DMA engine driver
   3 *
   4 * Copyright 2012 Texas Instruments
   5 *
   6 * This program is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU General Public License as
   8 * published by the Free Software Foundation version 2.
   9 *
  10 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
  11 * kind, whether express or implied; without even the implied warranty
  12 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 * GNU General Public License for more details.
  14 */
  15
  16#include <linux/dmaengine.h>
  17#include <linux/dma-mapping.h>
  18#include <linux/err.h>
  19#include <linux/init.h>
  20#include <linux/interrupt.h>
  21#include <linux/list.h>
  22#include <linux/module.h>
  23#include <linux/platform_device.h>
  24#include <linux/slab.h>
  25#include <linux/spinlock.h>
  26
  27#include <linux/platform_data/edma.h>
  28
  29#include "dmaengine.h"
  30#include "virt-dma.h"
  31
  32/*
  33 * This will go away when the private EDMA API is folded
  34 * into this driver and the platform device(s) are
  35 * instantiated in the arch code. We can only get away
  36 * with this simplification because DA8XX may not be built
  37 * in the same kernel image with other DaVinci parts. This
  38 * avoids having to sprinkle dmaengine driver platform devices
  39 * and data throughout all the existing board files.
  40 */
  41#ifdef CONFIG_ARCH_DAVINCI_DA8XX
  42#define EDMA_CTLRS      2
  43#define EDMA_CHANS      32
  44#else
  45#define EDMA_CTLRS      1
  46#define EDMA_CHANS      64
  47#endif /* CONFIG_ARCH_DAVINCI_DA8XX */
  48
  49/* Max of 16 segments per channel to conserve PaRAM slots */
  50#define MAX_NR_SG               16
  51#define EDMA_MAX_SLOTS          MAX_NR_SG
  52#define EDMA_DESCRIPTORS        16
  53
  54struct edma_desc {
  55        struct virt_dma_desc            vdesc;
  56        struct list_head                node;
  57        int                             absync;
  58        int                             pset_nr;
  59        struct edmacc_param             pset[0];
  60};
  61
  62struct edma_cc;
  63
  64struct edma_chan {
  65        struct virt_dma_chan            vchan;
  66        struct list_head                node;
  67        struct edma_desc                *edesc;
  68        struct edma_cc                  *ecc;
  69        int                             ch_num;
  70        bool                            alloced;
  71        int                             slot[EDMA_MAX_SLOTS];
  72        struct dma_slave_config         cfg;
  73};
  74
  75struct edma_cc {
  76        int                             ctlr;
  77        struct dma_device               dma_slave;
  78        struct edma_chan                slave_chans[EDMA_CHANS];
  79        int                             num_slave_chans;
  80        int                             dummy_slot;
  81};
  82
  83static inline struct edma_cc *to_edma_cc(struct dma_device *d)
  84{
  85        return container_of(d, struct edma_cc, dma_slave);
  86}
  87
  88static inline struct edma_chan *to_edma_chan(struct dma_chan *c)
  89{
  90        return container_of(c, struct edma_chan, vchan.chan);
  91}
  92
  93static inline struct edma_desc
  94*to_edma_desc(struct dma_async_tx_descriptor *tx)
  95{
  96        return container_of(tx, struct edma_desc, vdesc.tx);
  97}
  98
  99static void edma_desc_free(struct virt_dma_desc *vdesc)
 100{
 101        kfree(container_of(vdesc, struct edma_desc, vdesc));
 102}
 103
 104/* Dispatch a queued descriptor to the controller (caller holds lock) */
 105static void edma_execute(struct edma_chan *echan)
 106{
 107        struct virt_dma_desc *vdesc = vchan_next_desc(&echan->vchan);
 108        struct edma_desc *edesc;
 109        int i;
 110
 111        if (!vdesc) {
 112                echan->edesc = NULL;
 113                return;
 114        }
 115
 116        list_del(&vdesc->node);
 117
 118        echan->edesc = edesc = to_edma_desc(&vdesc->tx);
 119
 120        /* Write descriptor PaRAM set(s) */
 121        for (i = 0; i < edesc->pset_nr; i++) {
 122                edma_write_slot(echan->slot[i], &edesc->pset[i]);
 123                dev_dbg(echan->vchan.chan.device->dev,
 124                        "\n pset[%d]:\n"
 125                        "  chnum\t%d\n"
 126                        "  slot\t%d\n"
 127                        "  opt\t%08x\n"
 128                        "  src\t%08x\n"
 129                        "  dst\t%08x\n"
 130                        "  abcnt\t%08x\n"
 131                        "  ccnt\t%08x\n"
 132                        "  bidx\t%08x\n"
 133                        "  cidx\t%08x\n"
 134                        "  lkrld\t%08x\n",
 135                        i, echan->ch_num, echan->slot[i],
 136                        edesc->pset[i].opt,
 137                        edesc->pset[i].src,
 138                        edesc->pset[i].dst,
 139                        edesc->pset[i].a_b_cnt,
 140                        edesc->pset[i].ccnt,
 141                        edesc->pset[i].src_dst_bidx,
 142                        edesc->pset[i].src_dst_cidx,
 143                        edesc->pset[i].link_bcntrld);
 144                /* Link to the previous slot if not the last set */
 145                if (i != (edesc->pset_nr - 1))
 146                        edma_link(echan->slot[i], echan->slot[i+1]);
 147                /* Final pset links to the dummy pset */
 148                else
 149                        edma_link(echan->slot[i], echan->ecc->dummy_slot);
 150        }
 151
 152        edma_start(echan->ch_num);
 153}
 154
 155static int edma_terminate_all(struct edma_chan *echan)
 156{
 157        unsigned long flags;
 158        LIST_HEAD(head);
 159
 160        spin_lock_irqsave(&echan->vchan.lock, flags);
 161
 162        /*
 163         * Stop DMA activity: we assume the callback will not be called
 164         * after edma_dma() returns (even if it does, it will see
 165         * echan->edesc is NULL and exit.)
 166         */
 167        if (echan->edesc) {
 168                echan->edesc = NULL;
 169                edma_stop(echan->ch_num);
 170        }
 171
 172        vchan_get_all_descriptors(&echan->vchan, &head);
 173        spin_unlock_irqrestore(&echan->vchan.lock, flags);
 174        vchan_dma_desc_free_list(&echan->vchan, &head);
 175
 176        return 0;
 177}
 178
 179static int edma_slave_config(struct edma_chan *echan,
 180        struct dma_slave_config *cfg)
 181{
 182        if (cfg->src_addr_width == DMA_SLAVE_BUSWIDTH_8_BYTES ||
 183            cfg->dst_addr_width == DMA_SLAVE_BUSWIDTH_8_BYTES)
 184                return -EINVAL;
 185
 186        memcpy(&echan->cfg, cfg, sizeof(echan->cfg));
 187
 188        return 0;
 189}
 190
 191static int edma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
 192                        unsigned long arg)
 193{
 194        int ret = 0;
 195        struct dma_slave_config *config;
 196        struct edma_chan *echan = to_edma_chan(chan);
 197
 198        switch (cmd) {
 199        case DMA_TERMINATE_ALL:
 200                edma_terminate_all(echan);
 201                break;
 202        case DMA_SLAVE_CONFIG:
 203                config = (struct dma_slave_config *)arg;
 204                ret = edma_slave_config(echan, config);
 205                break;
 206        default:
 207                ret = -ENOSYS;
 208        }
 209
 210        return ret;
 211}
 212
 213static struct dma_async_tx_descriptor *edma_prep_slave_sg(
 214        struct dma_chan *chan, struct scatterlist *sgl,
 215        unsigned int sg_len, enum dma_transfer_direction direction,
 216        unsigned long tx_flags, void *context)
 217{
 218        struct edma_chan *echan = to_edma_chan(chan);
 219        struct device *dev = chan->device->dev;
 220        struct edma_desc *edesc;
 221        dma_addr_t dev_addr;
 222        enum dma_slave_buswidth dev_width;
 223        u32 burst;
 224        struct scatterlist *sg;
 225        int i;
 226        int acnt, bcnt, ccnt, src, dst, cidx;
 227        int src_bidx, dst_bidx, src_cidx, dst_cidx;
 228
 229        if (unlikely(!echan || !sgl || !sg_len))
 230                return NULL;
 231
 232        if (direction == DMA_DEV_TO_MEM) {
 233                dev_addr = echan->cfg.src_addr;
 234                dev_width = echan->cfg.src_addr_width;
 235                burst = echan->cfg.src_maxburst;
 236        } else if (direction == DMA_MEM_TO_DEV) {
 237                dev_addr = echan->cfg.dst_addr;
 238                dev_width = echan->cfg.dst_addr_width;
 239                burst = echan->cfg.dst_maxburst;
 240        } else {
 241                dev_err(dev, "%s: bad direction?\n", __func__);
 242                return NULL;
 243        }
 244
 245        if (dev_width == DMA_SLAVE_BUSWIDTH_UNDEFINED) {
 246                dev_err(dev, "Undefined slave buswidth\n");
 247                return NULL;
 248        }
 249
 250        if (sg_len > MAX_NR_SG) {
 251                dev_err(dev, "Exceeded max SG segments %d > %d\n",
 252                        sg_len, MAX_NR_SG);
 253                return NULL;
 254        }
 255
 256        edesc = kzalloc(sizeof(*edesc) + sg_len *
 257                sizeof(edesc->pset[0]), GFP_ATOMIC);
 258        if (!edesc) {
 259                dev_dbg(dev, "Failed to allocate a descriptor\n");
 260                return NULL;
 261        }
 262
 263        edesc->pset_nr = sg_len;
 264
 265        for_each_sg(sgl, sg, sg_len, i) {
 266                /* Allocate a PaRAM slot, if needed */
 267                if (echan->slot[i] < 0) {
 268                        echan->slot[i] =
 269                                edma_alloc_slot(EDMA_CTLR(echan->ch_num),
 270                                                EDMA_SLOT_ANY);
 271                        if (echan->slot[i] < 0) {
 272                                dev_err(dev, "Failed to allocate slot\n");
 273                                return NULL;
 274                        }
 275                }
 276
 277                acnt = dev_width;
 278
 279                /*
 280                 * If the maxburst is equal to the fifo width, use
 281                 * A-synced transfers. This allows for large contiguous
 282                 * buffer transfers using only one PaRAM set.
 283                 */
 284                if (burst == 1) {
 285                        edesc->absync = false;
 286                        ccnt = sg_dma_len(sg) / acnt / (SZ_64K - 1);
 287                        bcnt = sg_dma_len(sg) / acnt - ccnt * (SZ_64K - 1);
 288                        if (bcnt)
 289                                ccnt++;
 290                        else
 291                                bcnt = SZ_64K - 1;
 292                        cidx = acnt;
 293                /*
 294                 * If maxburst is greater than the fifo address_width,
 295                 * use AB-synced transfers where A count is the fifo
 296                 * address_width and B count is the maxburst. In this
 297                 * case, we are limited to transfers of C count frames
 298                 * of (address_width * maxburst) where C count is limited
 299                 * to SZ_64K-1. This places an upper bound on the length
 300                 * of an SG segment that can be handled.
 301                 */
 302                } else {
 303                        edesc->absync = true;
 304                        bcnt = burst;
 305                        ccnt = sg_dma_len(sg) / (acnt * bcnt);
 306                        if (ccnt > (SZ_64K - 1)) {
 307                                dev_err(dev, "Exceeded max SG segment size\n");
 308                                return NULL;
 309                        }
 310                        cidx = acnt * bcnt;
 311                }
 312
 313                if (direction == DMA_MEM_TO_DEV) {
 314                        src = sg_dma_address(sg);
 315                        dst = dev_addr;
 316                        src_bidx = acnt;
 317                        src_cidx = cidx;
 318                        dst_bidx = 0;
 319                        dst_cidx = 0;
 320                } else {
 321                        src = dev_addr;
 322                        dst = sg_dma_address(sg);
 323                        src_bidx = 0;
 324                        src_cidx = 0;
 325                        dst_bidx = acnt;
 326                        dst_cidx = cidx;
 327                }
 328
 329                edesc->pset[i].opt = EDMA_TCC(EDMA_CHAN_SLOT(echan->ch_num));
 330                /* Configure A or AB synchronized transfers */
 331                if (edesc->absync)
 332                        edesc->pset[i].opt |= SYNCDIM;
 333                /* If this is the last set, enable completion interrupt flag */
 334                if (i == sg_len - 1)
 335                        edesc->pset[i].opt |= TCINTEN;
 336
 337                edesc->pset[i].src = src;
 338                edesc->pset[i].dst = dst;
 339
 340                edesc->pset[i].src_dst_bidx = (dst_bidx << 16) | src_bidx;
 341                edesc->pset[i].src_dst_cidx = (dst_cidx << 16) | src_cidx;
 342
 343                edesc->pset[i].a_b_cnt = bcnt << 16 | acnt;
 344                edesc->pset[i].ccnt = ccnt;
 345                edesc->pset[i].link_bcntrld = 0xffffffff;
 346
 347        }
 348
 349        return vchan_tx_prep(&echan->vchan, &edesc->vdesc, tx_flags);
 350}
 351
 352static void edma_callback(unsigned ch_num, u16 ch_status, void *data)
 353{
 354        struct edma_chan *echan = data;
 355        struct device *dev = echan->vchan.chan.device->dev;
 356        struct edma_desc *edesc;
 357        unsigned long flags;
 358
 359        /* Stop the channel */
 360        edma_stop(echan->ch_num);
 361
 362        switch (ch_status) {
 363        case DMA_COMPLETE:
 364                dev_dbg(dev, "transfer complete on channel %d\n", ch_num);
 365
 366                spin_lock_irqsave(&echan->vchan.lock, flags);
 367
 368                edesc = echan->edesc;
 369                if (edesc) {
 370                        edma_execute(echan);
 371                        vchan_cookie_complete(&edesc->vdesc);
 372                }
 373
 374                spin_unlock_irqrestore(&echan->vchan.lock, flags);
 375
 376                break;
 377        case DMA_CC_ERROR:
 378                dev_dbg(dev, "transfer error on channel %d\n", ch_num);
 379                break;
 380        default:
 381                break;
 382        }
 383}
 384
 385/* Alloc channel resources */
 386static int edma_alloc_chan_resources(struct dma_chan *chan)
 387{
 388        struct edma_chan *echan = to_edma_chan(chan);
 389        struct device *dev = chan->device->dev;
 390        int ret;
 391        int a_ch_num;
 392        LIST_HEAD(descs);
 393
 394        a_ch_num = edma_alloc_channel(echan->ch_num, edma_callback,
 395                                        chan, EVENTQ_DEFAULT);
 396
 397        if (a_ch_num < 0) {
 398                ret = -ENODEV;
 399                goto err_no_chan;
 400        }
 401
 402        if (a_ch_num != echan->ch_num) {
 403                dev_err(dev, "failed to allocate requested channel %u:%u\n",
 404                        EDMA_CTLR(echan->ch_num),
 405                        EDMA_CHAN_SLOT(echan->ch_num));
 406                ret = -ENODEV;
 407                goto err_wrong_chan;
 408        }
 409
 410        echan->alloced = true;
 411        echan->slot[0] = echan->ch_num;
 412
 413        dev_info(dev, "allocated channel for %u:%u\n",
 414                 EDMA_CTLR(echan->ch_num), EDMA_CHAN_SLOT(echan->ch_num));
 415
 416        return 0;
 417
 418err_wrong_chan:
 419        edma_free_channel(a_ch_num);
 420err_no_chan:
 421        return ret;
 422}
 423
 424/* Free channel resources */
 425static void edma_free_chan_resources(struct dma_chan *chan)
 426{
 427        struct edma_chan *echan = to_edma_chan(chan);
 428        struct device *dev = chan->device->dev;
 429        int i;
 430
 431        /* Terminate transfers */
 432        edma_stop(echan->ch_num);
 433
 434        vchan_free_chan_resources(&echan->vchan);
 435
 436        /* Free EDMA PaRAM slots */
 437        for (i = 1; i < EDMA_MAX_SLOTS; i++) {
 438                if (echan->slot[i] >= 0) {
 439                        edma_free_slot(echan->slot[i]);
 440                        echan->slot[i] = -1;
 441                }
 442        }
 443
 444        /* Free EDMA channel */
 445        if (echan->alloced) {
 446                edma_free_channel(echan->ch_num);
 447                echan->alloced = false;
 448        }
 449
 450        dev_info(dev, "freeing channel for %u\n", echan->ch_num);
 451}
 452
 453/* Send pending descriptor to hardware */
 454static void edma_issue_pending(struct dma_chan *chan)
 455{
 456        struct edma_chan *echan = to_edma_chan(chan);
 457        unsigned long flags;
 458
 459        spin_lock_irqsave(&echan->vchan.lock, flags);
 460        if (vchan_issue_pending(&echan->vchan) && !echan->edesc)
 461                edma_execute(echan);
 462        spin_unlock_irqrestore(&echan->vchan.lock, flags);
 463}
 464
 465static size_t edma_desc_size(struct edma_desc *edesc)
 466{
 467        int i;
 468        size_t size;
 469
 470        if (edesc->absync)
 471                for (size = i = 0; i < edesc->pset_nr; i++)
 472                        size += (edesc->pset[i].a_b_cnt & 0xffff) *
 473                                (edesc->pset[i].a_b_cnt >> 16) *
 474                                 edesc->pset[i].ccnt;
 475        else
 476                size = (edesc->pset[0].a_b_cnt & 0xffff) *
 477                        (edesc->pset[0].a_b_cnt >> 16) +
 478                        (edesc->pset[0].a_b_cnt & 0xffff) *
 479                        (SZ_64K - 1) * edesc->pset[0].ccnt;
 480
 481        return size;
 482}
 483
 484/* Check request completion status */
 485static enum dma_status edma_tx_status(struct dma_chan *chan,
 486                                      dma_cookie_t cookie,
 487                                      struct dma_tx_state *txstate)
 488{
 489        struct edma_chan *echan = to_edma_chan(chan);
 490        struct virt_dma_desc *vdesc;
 491        enum dma_status ret;
 492        unsigned long flags;
 493
 494        ret = dma_cookie_status(chan, cookie, txstate);
 495        if (ret == DMA_SUCCESS || !txstate)
 496                return ret;
 497
 498        spin_lock_irqsave(&echan->vchan.lock, flags);
 499        vdesc = vchan_find_desc(&echan->vchan, cookie);
 500        if (vdesc) {
 501                txstate->residue = edma_desc_size(to_edma_desc(&vdesc->tx));
 502        } else if (echan->edesc && echan->edesc->vdesc.tx.cookie == cookie) {
 503                struct edma_desc *edesc = echan->edesc;
 504                txstate->residue = edma_desc_size(edesc);
 505        } else {
 506                txstate->residue = 0;
 507        }
 508        spin_unlock_irqrestore(&echan->vchan.lock, flags);
 509
 510        return ret;
 511}
 512
 513static void __init edma_chan_init(struct edma_cc *ecc,
 514                                  struct dma_device *dma,
 515                                  struct edma_chan *echans)
 516{
 517        int i, j;
 518
 519        for (i = 0; i < EDMA_CHANS; i++) {
 520                struct edma_chan *echan = &echans[i];
 521                echan->ch_num = EDMA_CTLR_CHAN(ecc->ctlr, i);
 522                echan->ecc = ecc;
 523                echan->vchan.desc_free = edma_desc_free;
 524
 525                vchan_init(&echan->vchan, dma);
 526
 527                INIT_LIST_HEAD(&echan->node);
 528                for (j = 0; j < EDMA_MAX_SLOTS; j++)
 529                        echan->slot[j] = -1;
 530        }
 531}
 532
 533static void edma_dma_init(struct edma_cc *ecc, struct dma_device *dma,
 534                          struct device *dev)
 535{
 536        dma->device_prep_slave_sg = edma_prep_slave_sg;
 537        dma->device_alloc_chan_resources = edma_alloc_chan_resources;
 538        dma->device_free_chan_resources = edma_free_chan_resources;
 539        dma->device_issue_pending = edma_issue_pending;
 540        dma->device_tx_status = edma_tx_status;
 541        dma->device_control = edma_control;
 542        dma->dev = dev;
 543
 544        INIT_LIST_HEAD(&dma->channels);
 545}
 546
 547static int edma_probe(struct platform_device *pdev)
 548{
 549        struct edma_cc *ecc;
 550        int ret;
 551
 552        ecc = devm_kzalloc(&pdev->dev, sizeof(*ecc), GFP_KERNEL);
 553        if (!ecc) {
 554                dev_err(&pdev->dev, "Can't allocate controller\n");
 555                return -ENOMEM;
 556        }
 557
 558        ecc->ctlr = pdev->id;
 559        ecc->dummy_slot = edma_alloc_slot(ecc->ctlr, EDMA_SLOT_ANY);
 560        if (ecc->dummy_slot < 0) {
 561                dev_err(&pdev->dev, "Can't allocate PaRAM dummy slot\n");
 562                return -EIO;
 563        }
 564
 565        dma_cap_zero(ecc->dma_slave.cap_mask);
 566        dma_cap_set(DMA_SLAVE, ecc->dma_slave.cap_mask);
 567
 568        edma_dma_init(ecc, &ecc->dma_slave, &pdev->dev);
 569
 570        edma_chan_init(ecc, &ecc->dma_slave, ecc->slave_chans);
 571
 572        ret = dma_async_device_register(&ecc->dma_slave);
 573        if (ret)
 574                goto err_reg1;
 575
 576        platform_set_drvdata(pdev, ecc);
 577
 578        dev_info(&pdev->dev, "TI EDMA DMA engine driver\n");
 579
 580        return 0;
 581
 582err_reg1:
 583        edma_free_slot(ecc->dummy_slot);
 584        return ret;
 585}
 586
 587static int edma_remove(struct platform_device *pdev)
 588{
 589        struct device *dev = &pdev->dev;
 590        struct edma_cc *ecc = dev_get_drvdata(dev);
 591
 592        dma_async_device_unregister(&ecc->dma_slave);
 593        edma_free_slot(ecc->dummy_slot);
 594
 595        return 0;
 596}
 597
 598static struct platform_driver edma_driver = {
 599        .probe          = edma_probe,
 600        .remove         = edma_remove,
 601        .driver = {
 602                .name = "edma-dma-engine",
 603                .owner = THIS_MODULE,
 604        },
 605};
 606
 607bool edma_filter_fn(struct dma_chan *chan, void *param)
 608{
 609        if (chan->device->dev->driver == &edma_driver.driver) {
 610                struct edma_chan *echan = to_edma_chan(chan);
 611                unsigned ch_req = *(unsigned *)param;
 612                return ch_req == echan->ch_num;
 613        }
 614        return false;
 615}
 616EXPORT_SYMBOL(edma_filter_fn);
 617
 618static struct platform_device *pdev0, *pdev1;
 619
 620static const struct platform_device_info edma_dev_info0 = {
 621        .name = "edma-dma-engine",
 622        .id = 0,
 623};
 624
 625static const struct platform_device_info edma_dev_info1 = {
 626        .name = "edma-dma-engine",
 627        .id = 1,
 628};
 629
 630static int edma_init(void)
 631{
 632        int ret = platform_driver_register(&edma_driver);
 633
 634        if (ret == 0) {
 635                pdev0 = platform_device_register_full(&edma_dev_info0);
 636                if (IS_ERR(pdev0)) {
 637                        platform_driver_unregister(&edma_driver);
 638                        ret = PTR_ERR(pdev0);
 639                        goto out;
 640                }
 641                pdev0->dev.dma_mask = &pdev0->dev.coherent_dma_mask;
 642                pdev0->dev.coherent_dma_mask = DMA_BIT_MASK(32);
 643        }
 644
 645        if (EDMA_CTLRS == 2) {
 646                pdev1 = platform_device_register_full(&edma_dev_info1);
 647                if (IS_ERR(pdev1)) {
 648                        platform_driver_unregister(&edma_driver);
 649                        platform_device_unregister(pdev0);
 650                        ret = PTR_ERR(pdev1);
 651                }
 652                pdev1->dev.dma_mask = &pdev1->dev.coherent_dma_mask;
 653                pdev1->dev.coherent_dma_mask = DMA_BIT_MASK(32);
 654        }
 655
 656out:
 657        return ret;
 658}
 659subsys_initcall(edma_init);
 660
 661static void __exit edma_exit(void)
 662{
 663        platform_device_unregister(pdev0);
 664        if (pdev1)
 665                platform_device_unregister(pdev1);
 666        platform_driver_unregister(&edma_driver);
 667}
 668module_exit(edma_exit);
 669
 670MODULE_AUTHOR("Matt Porter <mporter@ti.com>");
 671MODULE_DESCRIPTION("TI EDMA DMA engine driver");
 672MODULE_LICENSE("GPL v2");
 673