linux/drivers/dma/dmaengine.c
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   1/*
   2 * Copyright(c) 2004 - 2006 Intel Corporation. All rights reserved.
   3 *
   4 * This program is free software; you can redistribute it and/or modify it
   5 * under the terms of the GNU General Public License as published by the Free
   6 * Software Foundation; either version 2 of the License, or (at your option)
   7 * any later version.
   8 *
   9 * This program is distributed in the hope that it will be useful, but WITHOUT
  10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12 * more details.
  13 *
  14 * You should have received a copy of the GNU General Public License along with
  15 * this program; if not, write to the Free Software Foundation, Inc., 59
  16 * Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  17 *
  18 * The full GNU General Public License is included in this distribution in the
  19 * file called COPYING.
  20 */
  21
  22/*
  23 * This code implements the DMA subsystem. It provides a HW-neutral interface
  24 * for other kernel code to use asynchronous memory copy capabilities,
  25 * if present, and allows different HW DMA drivers to register as providing
  26 * this capability.
  27 *
  28 * Due to the fact we are accelerating what is already a relatively fast
  29 * operation, the code goes to great lengths to avoid additional overhead,
  30 * such as locking.
  31 *
  32 * LOCKING:
  33 *
  34 * The subsystem keeps a global list of dma_device structs it is protected by a
  35 * mutex, dma_list_mutex.
  36 *
  37 * A subsystem can get access to a channel by calling dmaengine_get() followed
  38 * by dma_find_channel(), or if it has need for an exclusive channel it can call
  39 * dma_request_channel().  Once a channel is allocated a reference is taken
  40 * against its corresponding driver to disable removal.
  41 *
  42 * Each device has a channels list, which runs unlocked but is never modified
  43 * once the device is registered, it's just setup by the driver.
  44 *
  45 * See Documentation/dmaengine.txt for more details
  46 */
  47
  48#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  49
  50#include <linux/dma-mapping.h>
  51#include <linux/init.h>
  52#include <linux/module.h>
  53#include <linux/mm.h>
  54#include <linux/device.h>
  55#include <linux/dmaengine.h>
  56#include <linux/hardirq.h>
  57#include <linux/spinlock.h>
  58#include <linux/percpu.h>
  59#include <linux/rcupdate.h>
  60#include <linux/mutex.h>
  61#include <linux/jiffies.h>
  62#include <linux/rculist.h>
  63#include <linux/idr.h>
  64#include <linux/slab.h>
  65#include <linux/of_dma.h>
  66
  67static DEFINE_MUTEX(dma_list_mutex);
  68static DEFINE_IDR(dma_idr);
  69static LIST_HEAD(dma_device_list);
  70static long dmaengine_ref_count;
  71
  72/* --- sysfs implementation --- */
  73
  74/**
  75 * dev_to_dma_chan - convert a device pointer to the its sysfs container object
  76 * @dev - device node
  77 *
  78 * Must be called under dma_list_mutex
  79 */
  80static struct dma_chan *dev_to_dma_chan(struct device *dev)
  81{
  82        struct dma_chan_dev *chan_dev;
  83
  84        chan_dev = container_of(dev, typeof(*chan_dev), device);
  85        return chan_dev->chan;
  86}
  87
  88static ssize_t show_memcpy_count(struct device *dev, struct device_attribute *attr, char *buf)
  89{
  90        struct dma_chan *chan;
  91        unsigned long count = 0;
  92        int i;
  93        int err;
  94
  95        mutex_lock(&dma_list_mutex);
  96        chan = dev_to_dma_chan(dev);
  97        if (chan) {
  98                for_each_possible_cpu(i)
  99                        count += per_cpu_ptr(chan->local, i)->memcpy_count;
 100                err = sprintf(buf, "%lu\n", count);
 101        } else
 102                err = -ENODEV;
 103        mutex_unlock(&dma_list_mutex);
 104
 105        return err;
 106}
 107
 108static ssize_t show_bytes_transferred(struct device *dev, struct device_attribute *attr,
 109                                      char *buf)
 110{
 111        struct dma_chan *chan;
 112        unsigned long count = 0;
 113        int i;
 114        int err;
 115
 116        mutex_lock(&dma_list_mutex);
 117        chan = dev_to_dma_chan(dev);
 118        if (chan) {
 119                for_each_possible_cpu(i)
 120                        count += per_cpu_ptr(chan->local, i)->bytes_transferred;
 121                err = sprintf(buf, "%lu\n", count);
 122        } else
 123                err = -ENODEV;
 124        mutex_unlock(&dma_list_mutex);
 125
 126        return err;
 127}
 128
 129static ssize_t show_in_use(struct device *dev, struct device_attribute *attr, char *buf)
 130{
 131        struct dma_chan *chan;
 132        int err;
 133
 134        mutex_lock(&dma_list_mutex);
 135        chan = dev_to_dma_chan(dev);
 136        if (chan)
 137                err = sprintf(buf, "%d\n", chan->client_count);
 138        else
 139                err = -ENODEV;
 140        mutex_unlock(&dma_list_mutex);
 141
 142        return err;
 143}
 144
 145static struct device_attribute dma_attrs[] = {
 146        __ATTR(memcpy_count, S_IRUGO, show_memcpy_count, NULL),
 147        __ATTR(bytes_transferred, S_IRUGO, show_bytes_transferred, NULL),
 148        __ATTR(in_use, S_IRUGO, show_in_use, NULL),
 149        __ATTR_NULL
 150};
 151
 152static void chan_dev_release(struct device *dev)
 153{
 154        struct dma_chan_dev *chan_dev;
 155
 156        chan_dev = container_of(dev, typeof(*chan_dev), device);
 157        if (atomic_dec_and_test(chan_dev->idr_ref)) {
 158                mutex_lock(&dma_list_mutex);
 159                idr_remove(&dma_idr, chan_dev->dev_id);
 160                mutex_unlock(&dma_list_mutex);
 161                kfree(chan_dev->idr_ref);
 162        }
 163        kfree(chan_dev);
 164}
 165
 166static struct class dma_devclass = {
 167        .name           = "dma",
 168        .dev_attrs      = dma_attrs,
 169        .dev_release    = chan_dev_release,
 170};
 171
 172/* --- client and device registration --- */
 173
 174#define dma_device_satisfies_mask(device, mask) \
 175        __dma_device_satisfies_mask((device), &(mask))
 176static int
 177__dma_device_satisfies_mask(struct dma_device *device, dma_cap_mask_t *want)
 178{
 179        dma_cap_mask_t has;
 180
 181        bitmap_and(has.bits, want->bits, device->cap_mask.bits,
 182                DMA_TX_TYPE_END);
 183        return bitmap_equal(want->bits, has.bits, DMA_TX_TYPE_END);
 184}
 185
 186static struct module *dma_chan_to_owner(struct dma_chan *chan)
 187{
 188        return chan->device->dev->driver->owner;
 189}
 190
 191/**
 192 * balance_ref_count - catch up the channel reference count
 193 * @chan - channel to balance ->client_count versus dmaengine_ref_count
 194 *
 195 * balance_ref_count must be called under dma_list_mutex
 196 */
 197static void balance_ref_count(struct dma_chan *chan)
 198{
 199        struct module *owner = dma_chan_to_owner(chan);
 200
 201        while (chan->client_count < dmaengine_ref_count) {
 202                __module_get(owner);
 203                chan->client_count++;
 204        }
 205}
 206
 207/**
 208 * dma_chan_get - try to grab a dma channel's parent driver module
 209 * @chan - channel to grab
 210 *
 211 * Must be called under dma_list_mutex
 212 */
 213static int dma_chan_get(struct dma_chan *chan)
 214{
 215        int err = -ENODEV;
 216        struct module *owner = dma_chan_to_owner(chan);
 217
 218        if (chan->client_count) {
 219                __module_get(owner);
 220                err = 0;
 221        } else if (try_module_get(owner))
 222                err = 0;
 223
 224        if (err == 0)
 225                chan->client_count++;
 226
 227        /* allocate upon first client reference */
 228        if (chan->client_count == 1 && err == 0) {
 229                int desc_cnt = chan->device->device_alloc_chan_resources(chan);
 230
 231                if (desc_cnt < 0) {
 232                        err = desc_cnt;
 233                        chan->client_count = 0;
 234                        module_put(owner);
 235                } else if (!dma_has_cap(DMA_PRIVATE, chan->device->cap_mask))
 236                        balance_ref_count(chan);
 237        }
 238
 239        return err;
 240}
 241
 242/**
 243 * dma_chan_put - drop a reference to a dma channel's parent driver module
 244 * @chan - channel to release
 245 *
 246 * Must be called under dma_list_mutex
 247 */
 248static void dma_chan_put(struct dma_chan *chan)
 249{
 250        if (!chan->client_count)
 251                return; /* this channel failed alloc_chan_resources */
 252        chan->client_count--;
 253        module_put(dma_chan_to_owner(chan));
 254        if (chan->client_count == 0)
 255                chan->device->device_free_chan_resources(chan);
 256}
 257
 258enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie)
 259{
 260        enum dma_status status;
 261        unsigned long dma_sync_wait_timeout = jiffies + msecs_to_jiffies(5000);
 262
 263        dma_async_issue_pending(chan);
 264        do {
 265                status = dma_async_is_tx_complete(chan, cookie, NULL, NULL);
 266                if (time_after_eq(jiffies, dma_sync_wait_timeout)) {
 267                        pr_err("%s: timeout!\n", __func__);
 268                        return DMA_ERROR;
 269                }
 270                if (status != DMA_IN_PROGRESS)
 271                        break;
 272                cpu_relax();
 273        } while (1);
 274
 275        return status;
 276}
 277EXPORT_SYMBOL(dma_sync_wait);
 278
 279/**
 280 * dma_cap_mask_all - enable iteration over all operation types
 281 */
 282static dma_cap_mask_t dma_cap_mask_all;
 283
 284/**
 285 * dma_chan_tbl_ent - tracks channel allocations per core/operation
 286 * @chan - associated channel for this entry
 287 */
 288struct dma_chan_tbl_ent {
 289        struct dma_chan *chan;
 290};
 291
 292/**
 293 * channel_table - percpu lookup table for memory-to-memory offload providers
 294 */
 295static struct dma_chan_tbl_ent __percpu *channel_table[DMA_TX_TYPE_END];
 296
 297static int __init dma_channel_table_init(void)
 298{
 299        enum dma_transaction_type cap;
 300        int err = 0;
 301
 302        bitmap_fill(dma_cap_mask_all.bits, DMA_TX_TYPE_END);
 303
 304        /* 'interrupt', 'private', and 'slave' are channel capabilities,
 305         * but are not associated with an operation so they do not need
 306         * an entry in the channel_table
 307         */
 308        clear_bit(DMA_INTERRUPT, dma_cap_mask_all.bits);
 309        clear_bit(DMA_PRIVATE, dma_cap_mask_all.bits);
 310        clear_bit(DMA_SLAVE, dma_cap_mask_all.bits);
 311
 312        for_each_dma_cap_mask(cap, dma_cap_mask_all) {
 313                channel_table[cap] = alloc_percpu(struct dma_chan_tbl_ent);
 314                if (!channel_table[cap]) {
 315                        err = -ENOMEM;
 316                        break;
 317                }
 318        }
 319
 320        if (err) {
 321                pr_err("initialization failure\n");
 322                for_each_dma_cap_mask(cap, dma_cap_mask_all)
 323                        if (channel_table[cap])
 324                                free_percpu(channel_table[cap]);
 325        }
 326
 327        return err;
 328}
 329arch_initcall(dma_channel_table_init);
 330
 331/**
 332 * dma_find_channel - find a channel to carry out the operation
 333 * @tx_type: transaction type
 334 */
 335struct dma_chan *dma_find_channel(enum dma_transaction_type tx_type)
 336{
 337        return this_cpu_read(channel_table[tx_type]->chan);
 338}
 339EXPORT_SYMBOL(dma_find_channel);
 340
 341/*
 342 * net_dma_find_channel - find a channel for net_dma
 343 * net_dma has alignment requirements
 344 */
 345struct dma_chan *net_dma_find_channel(void)
 346{
 347        struct dma_chan *chan = dma_find_channel(DMA_MEMCPY);
 348        if (chan && !is_dma_copy_aligned(chan->device, 1, 1, 1))
 349                return NULL;
 350
 351        return chan;
 352}
 353EXPORT_SYMBOL(net_dma_find_channel);
 354
 355/**
 356 * dma_issue_pending_all - flush all pending operations across all channels
 357 */
 358void dma_issue_pending_all(void)
 359{
 360        struct dma_device *device;
 361        struct dma_chan *chan;
 362
 363        rcu_read_lock();
 364        list_for_each_entry_rcu(device, &dma_device_list, global_node) {
 365                if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
 366                        continue;
 367                list_for_each_entry(chan, &device->channels, device_node)
 368                        if (chan->client_count)
 369                                device->device_issue_pending(chan);
 370        }
 371        rcu_read_unlock();
 372}
 373EXPORT_SYMBOL(dma_issue_pending_all);
 374
 375/**
 376 * nth_chan - returns the nth channel of the given capability
 377 * @cap: capability to match
 378 * @n: nth channel desired
 379 *
 380 * Defaults to returning the channel with the desired capability and the
 381 * lowest reference count when 'n' cannot be satisfied.  Must be called
 382 * under dma_list_mutex.
 383 */
 384static struct dma_chan *nth_chan(enum dma_transaction_type cap, int n)
 385{
 386        struct dma_device *device;
 387        struct dma_chan *chan;
 388        struct dma_chan *ret = NULL;
 389        struct dma_chan *min = NULL;
 390
 391        list_for_each_entry(device, &dma_device_list, global_node) {
 392                if (!dma_has_cap(cap, device->cap_mask) ||
 393                    dma_has_cap(DMA_PRIVATE, device->cap_mask))
 394                        continue;
 395                list_for_each_entry(chan, &device->channels, device_node) {
 396                        if (!chan->client_count)
 397                                continue;
 398                        if (!min)
 399                                min = chan;
 400                        else if (chan->table_count < min->table_count)
 401                                min = chan;
 402
 403                        if (n-- == 0) {
 404                                ret = chan;
 405                                break; /* done */
 406                        }
 407                }
 408                if (ret)
 409                        break; /* done */
 410        }
 411
 412        if (!ret)
 413                ret = min;
 414
 415        if (ret)
 416                ret->table_count++;
 417
 418        return ret;
 419}
 420
 421/**
 422 * dma_channel_rebalance - redistribute the available channels
 423 *
 424 * Optimize for cpu isolation (each cpu gets a dedicated channel for an
 425 * operation type) in the SMP case,  and operation isolation (avoid
 426 * multi-tasking channels) in the non-SMP case.  Must be called under
 427 * dma_list_mutex.
 428 */
 429static void dma_channel_rebalance(void)
 430{
 431        struct dma_chan *chan;
 432        struct dma_device *device;
 433        int cpu;
 434        int cap;
 435        int n;
 436
 437        /* undo the last distribution */
 438        for_each_dma_cap_mask(cap, dma_cap_mask_all)
 439                for_each_possible_cpu(cpu)
 440                        per_cpu_ptr(channel_table[cap], cpu)->chan = NULL;
 441
 442        list_for_each_entry(device, &dma_device_list, global_node) {
 443                if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
 444                        continue;
 445                list_for_each_entry(chan, &device->channels, device_node)
 446                        chan->table_count = 0;
 447        }
 448
 449        /* don't populate the channel_table if no clients are available */
 450        if (!dmaengine_ref_count)
 451                return;
 452
 453        /* redistribute available channels */
 454        n = 0;
 455        for_each_dma_cap_mask(cap, dma_cap_mask_all)
 456                for_each_online_cpu(cpu) {
 457                        if (num_possible_cpus() > 1)
 458                                chan = nth_chan(cap, n++);
 459                        else
 460                                chan = nth_chan(cap, -1);
 461
 462                        per_cpu_ptr(channel_table[cap], cpu)->chan = chan;
 463                }
 464}
 465
 466static struct dma_chan *private_candidate(dma_cap_mask_t *mask, struct dma_device *dev,
 467                                          dma_filter_fn fn, void *fn_param)
 468{
 469        struct dma_chan *chan;
 470
 471        if (!__dma_device_satisfies_mask(dev, mask)) {
 472                pr_debug("%s: wrong capabilities\n", __func__);
 473                return NULL;
 474        }
 475        /* devices with multiple channels need special handling as we need to
 476         * ensure that all channels are either private or public.
 477         */
 478        if (dev->chancnt > 1 && !dma_has_cap(DMA_PRIVATE, dev->cap_mask))
 479                list_for_each_entry(chan, &dev->channels, device_node) {
 480                        /* some channels are already publicly allocated */
 481                        if (chan->client_count)
 482                                return NULL;
 483                }
 484
 485        list_for_each_entry(chan, &dev->channels, device_node) {
 486                if (chan->client_count) {
 487                        pr_debug("%s: %s busy\n",
 488                                 __func__, dma_chan_name(chan));
 489                        continue;
 490                }
 491                if (fn && !fn(chan, fn_param)) {
 492                        pr_debug("%s: %s filter said false\n",
 493                                 __func__, dma_chan_name(chan));
 494                        continue;
 495                }
 496                return chan;
 497        }
 498
 499        return NULL;
 500}
 501
 502/**
 503 * dma_request_channel - try to allocate an exclusive channel
 504 * @mask: capabilities that the channel must satisfy
 505 * @fn: optional callback to disposition available channels
 506 * @fn_param: opaque parameter to pass to dma_filter_fn
 507 */
 508struct dma_chan *__dma_request_channel(dma_cap_mask_t *mask, dma_filter_fn fn, void *fn_param)
 509{
 510        struct dma_device *device, *_d;
 511        struct dma_chan *chan = NULL;
 512        int err;
 513
 514        /* Find a channel */
 515        mutex_lock(&dma_list_mutex);
 516        list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
 517                chan = private_candidate(mask, device, fn, fn_param);
 518                if (chan) {
 519                        /* Found a suitable channel, try to grab, prep, and
 520                         * return it.  We first set DMA_PRIVATE to disable
 521                         * balance_ref_count as this channel will not be
 522                         * published in the general-purpose allocator
 523                         */
 524                        dma_cap_set(DMA_PRIVATE, device->cap_mask);
 525                        device->privatecnt++;
 526                        err = dma_chan_get(chan);
 527
 528                        if (err == -ENODEV) {
 529                                pr_debug("%s: %s module removed\n",
 530                                         __func__, dma_chan_name(chan));
 531                                list_del_rcu(&device->global_node);
 532                        } else if (err)
 533                                pr_debug("%s: failed to get %s: (%d)\n",
 534                                         __func__, dma_chan_name(chan), err);
 535                        else
 536                                break;
 537                        if (--device->privatecnt == 0)
 538                                dma_cap_clear(DMA_PRIVATE, device->cap_mask);
 539                        chan = NULL;
 540                }
 541        }
 542        mutex_unlock(&dma_list_mutex);
 543
 544        pr_debug("%s: %s (%s)\n",
 545                 __func__,
 546                 chan ? "success" : "fail",
 547                 chan ? dma_chan_name(chan) : NULL);
 548
 549        return chan;
 550}
 551EXPORT_SYMBOL_GPL(__dma_request_channel);
 552
 553/**
 554 * dma_request_slave_channel - try to allocate an exclusive slave channel
 555 * @dev:        pointer to client device structure
 556 * @name:       slave channel name
 557 */
 558struct dma_chan *dma_request_slave_channel(struct device *dev, char *name)
 559{
 560        /* If device-tree is present get slave info from here */
 561        if (dev->of_node)
 562                return of_dma_request_slave_channel(dev->of_node, name);
 563
 564        return NULL;
 565}
 566EXPORT_SYMBOL_GPL(dma_request_slave_channel);
 567
 568void dma_release_channel(struct dma_chan *chan)
 569{
 570        mutex_lock(&dma_list_mutex);
 571        WARN_ONCE(chan->client_count != 1,
 572                  "chan reference count %d != 1\n", chan->client_count);
 573        dma_chan_put(chan);
 574        /* drop PRIVATE cap enabled by __dma_request_channel() */
 575        if (--chan->device->privatecnt == 0)
 576                dma_cap_clear(DMA_PRIVATE, chan->device->cap_mask);
 577        mutex_unlock(&dma_list_mutex);
 578}
 579EXPORT_SYMBOL_GPL(dma_release_channel);
 580
 581/**
 582 * dmaengine_get - register interest in dma_channels
 583 */
 584void dmaengine_get(void)
 585{
 586        struct dma_device *device, *_d;
 587        struct dma_chan *chan;
 588        int err;
 589
 590        mutex_lock(&dma_list_mutex);
 591        dmaengine_ref_count++;
 592
 593        /* try to grab channels */
 594        list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
 595                if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
 596                        continue;
 597                list_for_each_entry(chan, &device->channels, device_node) {
 598                        err = dma_chan_get(chan);
 599                        if (err == -ENODEV) {
 600                                /* module removed before we could use it */
 601                                list_del_rcu(&device->global_node);
 602                                break;
 603                        } else if (err)
 604                                pr_debug("%s: failed to get %s: (%d)\n",
 605                                       __func__, dma_chan_name(chan), err);
 606                }
 607        }
 608
 609        /* if this is the first reference and there were channels
 610         * waiting we need to rebalance to get those channels
 611         * incorporated into the channel table
 612         */
 613        if (dmaengine_ref_count == 1)
 614                dma_channel_rebalance();
 615        mutex_unlock(&dma_list_mutex);
 616}
 617EXPORT_SYMBOL(dmaengine_get);
 618
 619/**
 620 * dmaengine_put - let dma drivers be removed when ref_count == 0
 621 */
 622void dmaengine_put(void)
 623{
 624        struct dma_device *device;
 625        struct dma_chan *chan;
 626
 627        mutex_lock(&dma_list_mutex);
 628        dmaengine_ref_count--;
 629        BUG_ON(dmaengine_ref_count < 0);
 630        /* drop channel references */
 631        list_for_each_entry(device, &dma_device_list, global_node) {
 632                if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
 633                        continue;
 634                list_for_each_entry(chan, &device->channels, device_node)
 635                        dma_chan_put(chan);
 636        }
 637        mutex_unlock(&dma_list_mutex);
 638}
 639EXPORT_SYMBOL(dmaengine_put);
 640
 641static bool device_has_all_tx_types(struct dma_device *device)
 642{
 643        /* A device that satisfies this test has channels that will never cause
 644         * an async_tx channel switch event as all possible operation types can
 645         * be handled.
 646         */
 647        #ifdef CONFIG_ASYNC_TX_DMA
 648        if (!dma_has_cap(DMA_INTERRUPT, device->cap_mask))
 649                return false;
 650        #endif
 651
 652        #if defined(CONFIG_ASYNC_MEMCPY) || defined(CONFIG_ASYNC_MEMCPY_MODULE)
 653        if (!dma_has_cap(DMA_MEMCPY, device->cap_mask))
 654                return false;
 655        #endif
 656
 657        #if defined(CONFIG_ASYNC_MEMSET) || defined(CONFIG_ASYNC_MEMSET_MODULE)
 658        if (!dma_has_cap(DMA_MEMSET, device->cap_mask))
 659                return false;
 660        #endif
 661
 662        #if defined(CONFIG_ASYNC_XOR) || defined(CONFIG_ASYNC_XOR_MODULE)
 663        if (!dma_has_cap(DMA_XOR, device->cap_mask))
 664                return false;
 665
 666        #ifndef CONFIG_ASYNC_TX_DISABLE_XOR_VAL_DMA
 667        if (!dma_has_cap(DMA_XOR_VAL, device->cap_mask))
 668                return false;
 669        #endif
 670        #endif
 671
 672        #if defined(CONFIG_ASYNC_PQ) || defined(CONFIG_ASYNC_PQ_MODULE)
 673        if (!dma_has_cap(DMA_PQ, device->cap_mask))
 674                return false;
 675
 676        #ifndef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA
 677        if (!dma_has_cap(DMA_PQ_VAL, device->cap_mask))
 678                return false;
 679        #endif
 680        #endif
 681
 682        return true;
 683}
 684
 685static int get_dma_id(struct dma_device *device)
 686{
 687        int rc;
 688
 689        mutex_lock(&dma_list_mutex);
 690
 691        rc = idr_alloc(&dma_idr, NULL, 0, 0, GFP_KERNEL);
 692        if (rc >= 0)
 693                device->dev_id = rc;
 694
 695        mutex_unlock(&dma_list_mutex);
 696        return rc < 0 ? rc : 0;
 697}
 698
 699/**
 700 * dma_async_device_register - registers DMA devices found
 701 * @device: &dma_device
 702 */
 703int dma_async_device_register(struct dma_device *device)
 704{
 705        int chancnt = 0, rc;
 706        struct dma_chan* chan;
 707        atomic_t *idr_ref;
 708
 709        if (!device)
 710                return -ENODEV;
 711
 712        /* validate device routines */
 713        BUG_ON(dma_has_cap(DMA_MEMCPY, device->cap_mask) &&
 714                !device->device_prep_dma_memcpy);
 715        BUG_ON(dma_has_cap(DMA_XOR, device->cap_mask) &&
 716                !device->device_prep_dma_xor);
 717        BUG_ON(dma_has_cap(DMA_XOR_VAL, device->cap_mask) &&
 718                !device->device_prep_dma_xor_val);
 719        BUG_ON(dma_has_cap(DMA_PQ, device->cap_mask) &&
 720                !device->device_prep_dma_pq);
 721        BUG_ON(dma_has_cap(DMA_PQ_VAL, device->cap_mask) &&
 722                !device->device_prep_dma_pq_val);
 723        BUG_ON(dma_has_cap(DMA_MEMSET, device->cap_mask) &&
 724                !device->device_prep_dma_memset);
 725        BUG_ON(dma_has_cap(DMA_INTERRUPT, device->cap_mask) &&
 726                !device->device_prep_dma_interrupt);
 727        BUG_ON(dma_has_cap(DMA_SG, device->cap_mask) &&
 728                !device->device_prep_dma_sg);
 729        BUG_ON(dma_has_cap(DMA_CYCLIC, device->cap_mask) &&
 730                !device->device_prep_dma_cyclic);
 731        BUG_ON(dma_has_cap(DMA_SLAVE, device->cap_mask) &&
 732                !device->device_control);
 733        BUG_ON(dma_has_cap(DMA_INTERLEAVE, device->cap_mask) &&
 734                !device->device_prep_interleaved_dma);
 735
 736        BUG_ON(!device->device_alloc_chan_resources);
 737        BUG_ON(!device->device_free_chan_resources);
 738        BUG_ON(!device->device_tx_status);
 739        BUG_ON(!device->device_issue_pending);
 740        BUG_ON(!device->dev);
 741
 742        /* note: this only matters in the
 743         * CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH=n case
 744         */
 745        if (device_has_all_tx_types(device))
 746                dma_cap_set(DMA_ASYNC_TX, device->cap_mask);
 747
 748        idr_ref = kmalloc(sizeof(*idr_ref), GFP_KERNEL);
 749        if (!idr_ref)
 750                return -ENOMEM;
 751        rc = get_dma_id(device);
 752        if (rc != 0) {
 753                kfree(idr_ref);
 754                return rc;
 755        }
 756
 757        atomic_set(idr_ref, 0);
 758
 759        /* represent channels in sysfs. Probably want devs too */
 760        list_for_each_entry(chan, &device->channels, device_node) {
 761                rc = -ENOMEM;
 762                chan->local = alloc_percpu(typeof(*chan->local));
 763                if (chan->local == NULL)
 764                        goto err_out;
 765                chan->dev = kzalloc(sizeof(*chan->dev), GFP_KERNEL);
 766                if (chan->dev == NULL) {
 767                        free_percpu(chan->local);
 768                        chan->local = NULL;
 769                        goto err_out;
 770                }
 771
 772                chan->chan_id = chancnt++;
 773                chan->dev->device.class = &dma_devclass;
 774                chan->dev->device.parent = device->dev;
 775                chan->dev->chan = chan;
 776                chan->dev->idr_ref = idr_ref;
 777                chan->dev->dev_id = device->dev_id;
 778                atomic_inc(idr_ref);
 779                dev_set_name(&chan->dev->device, "dma%dchan%d",
 780                             device->dev_id, chan->chan_id);
 781
 782                rc = device_register(&chan->dev->device);
 783                if (rc) {
 784                        free_percpu(chan->local);
 785                        chan->local = NULL;
 786                        kfree(chan->dev);
 787                        atomic_dec(idr_ref);
 788                        goto err_out;
 789                }
 790                chan->client_count = 0;
 791        }
 792        device->chancnt = chancnt;
 793
 794        mutex_lock(&dma_list_mutex);
 795        /* take references on public channels */
 796        if (dmaengine_ref_count && !dma_has_cap(DMA_PRIVATE, device->cap_mask))
 797                list_for_each_entry(chan, &device->channels, device_node) {
 798                        /* if clients are already waiting for channels we need
 799                         * to take references on their behalf
 800                         */
 801                        if (dma_chan_get(chan) == -ENODEV) {
 802                                /* note we can only get here for the first
 803                                 * channel as the remaining channels are
 804                                 * guaranteed to get a reference
 805                                 */
 806                                rc = -ENODEV;
 807                                mutex_unlock(&dma_list_mutex);
 808                                goto err_out;
 809                        }
 810                }
 811        list_add_tail_rcu(&device->global_node, &dma_device_list);
 812        if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
 813                device->privatecnt++;   /* Always private */
 814        dma_channel_rebalance();
 815        mutex_unlock(&dma_list_mutex);
 816
 817        return 0;
 818
 819err_out:
 820        /* if we never registered a channel just release the idr */
 821        if (atomic_read(idr_ref) == 0) {
 822                mutex_lock(&dma_list_mutex);
 823                idr_remove(&dma_idr, device->dev_id);
 824                mutex_unlock(&dma_list_mutex);
 825                kfree(idr_ref);
 826                return rc;
 827        }
 828
 829        list_for_each_entry(chan, &device->channels, device_node) {
 830                if (chan->local == NULL)
 831                        continue;
 832                mutex_lock(&dma_list_mutex);
 833                chan->dev->chan = NULL;
 834                mutex_unlock(&dma_list_mutex);
 835                device_unregister(&chan->dev->device);
 836                free_percpu(chan->local);
 837        }
 838        return rc;
 839}
 840EXPORT_SYMBOL(dma_async_device_register);
 841
 842/**
 843 * dma_async_device_unregister - unregister a DMA device
 844 * @device: &dma_device
 845 *
 846 * This routine is called by dma driver exit routines, dmaengine holds module
 847 * references to prevent it being called while channels are in use.
 848 */
 849void dma_async_device_unregister(struct dma_device *device)
 850{
 851        struct dma_chan *chan;
 852
 853        mutex_lock(&dma_list_mutex);
 854        list_del_rcu(&device->global_node);
 855        dma_channel_rebalance();
 856        mutex_unlock(&dma_list_mutex);
 857
 858        list_for_each_entry(chan, &device->channels, device_node) {
 859                WARN_ONCE(chan->client_count,
 860                          "%s called while %d clients hold a reference\n",
 861                          __func__, chan->client_count);
 862                mutex_lock(&dma_list_mutex);
 863                chan->dev->chan = NULL;
 864                mutex_unlock(&dma_list_mutex);
 865                device_unregister(&chan->dev->device);
 866                free_percpu(chan->local);
 867        }
 868}
 869EXPORT_SYMBOL(dma_async_device_unregister);
 870
 871/**
 872 * dma_async_memcpy_buf_to_buf - offloaded copy between virtual addresses
 873 * @chan: DMA channel to offload copy to
 874 * @dest: destination address (virtual)
 875 * @src: source address (virtual)
 876 * @len: length
 877 *
 878 * Both @dest and @src must be mappable to a bus address according to the
 879 * DMA mapping API rules for streaming mappings.
 880 * Both @dest and @src must stay memory resident (kernel memory or locked
 881 * user space pages).
 882 */
 883dma_cookie_t
 884dma_async_memcpy_buf_to_buf(struct dma_chan *chan, void *dest,
 885                        void *src, size_t len)
 886{
 887        struct dma_device *dev = chan->device;
 888        struct dma_async_tx_descriptor *tx;
 889        dma_addr_t dma_dest, dma_src;
 890        dma_cookie_t cookie;
 891        unsigned long flags;
 892
 893        dma_src = dma_map_single(dev->dev, src, len, DMA_TO_DEVICE);
 894        dma_dest = dma_map_single(dev->dev, dest, len, DMA_FROM_DEVICE);
 895        flags = DMA_CTRL_ACK |
 896                DMA_COMPL_SRC_UNMAP_SINGLE |
 897                DMA_COMPL_DEST_UNMAP_SINGLE;
 898        tx = dev->device_prep_dma_memcpy(chan, dma_dest, dma_src, len, flags);
 899
 900        if (!tx) {
 901                dma_unmap_single(dev->dev, dma_src, len, DMA_TO_DEVICE);
 902                dma_unmap_single(dev->dev, dma_dest, len, DMA_FROM_DEVICE);
 903                return -ENOMEM;
 904        }
 905
 906        tx->callback = NULL;
 907        cookie = tx->tx_submit(tx);
 908
 909        preempt_disable();
 910        __this_cpu_add(chan->local->bytes_transferred, len);
 911        __this_cpu_inc(chan->local->memcpy_count);
 912        preempt_enable();
 913
 914        return cookie;
 915}
 916EXPORT_SYMBOL(dma_async_memcpy_buf_to_buf);
 917
 918/**
 919 * dma_async_memcpy_buf_to_pg - offloaded copy from address to page
 920 * @chan: DMA channel to offload copy to
 921 * @page: destination page
 922 * @offset: offset in page to copy to
 923 * @kdata: source address (virtual)
 924 * @len: length
 925 *
 926 * Both @page/@offset and @kdata must be mappable to a bus address according
 927 * to the DMA mapping API rules for streaming mappings.
 928 * Both @page/@offset and @kdata must stay memory resident (kernel memory or
 929 * locked user space pages)
 930 */
 931dma_cookie_t
 932dma_async_memcpy_buf_to_pg(struct dma_chan *chan, struct page *page,
 933                        unsigned int offset, void *kdata, size_t len)
 934{
 935        struct dma_device *dev = chan->device;
 936        struct dma_async_tx_descriptor *tx;
 937        dma_addr_t dma_dest, dma_src;
 938        dma_cookie_t cookie;
 939        unsigned long flags;
 940
 941        dma_src = dma_map_single(dev->dev, kdata, len, DMA_TO_DEVICE);
 942        dma_dest = dma_map_page(dev->dev, page, offset, len, DMA_FROM_DEVICE);
 943        flags = DMA_CTRL_ACK | DMA_COMPL_SRC_UNMAP_SINGLE;
 944        tx = dev->device_prep_dma_memcpy(chan, dma_dest, dma_src, len, flags);
 945
 946        if (!tx) {
 947                dma_unmap_single(dev->dev, dma_src, len, DMA_TO_DEVICE);
 948                dma_unmap_page(dev->dev, dma_dest, len, DMA_FROM_DEVICE);
 949                return -ENOMEM;
 950        }
 951
 952        tx->callback = NULL;
 953        cookie = tx->tx_submit(tx);
 954
 955        preempt_disable();
 956        __this_cpu_add(chan->local->bytes_transferred, len);
 957        __this_cpu_inc(chan->local->memcpy_count);
 958        preempt_enable();
 959
 960        return cookie;
 961}
 962EXPORT_SYMBOL(dma_async_memcpy_buf_to_pg);
 963
 964/**
 965 * dma_async_memcpy_pg_to_pg - offloaded copy from page to page
 966 * @chan: DMA channel to offload copy to
 967 * @dest_pg: destination page
 968 * @dest_off: offset in page to copy to
 969 * @src_pg: source page
 970 * @src_off: offset in page to copy from
 971 * @len: length
 972 *
 973 * Both @dest_page/@dest_off and @src_page/@src_off must be mappable to a bus
 974 * address according to the DMA mapping API rules for streaming mappings.
 975 * Both @dest_page/@dest_off and @src_page/@src_off must stay memory resident
 976 * (kernel memory or locked user space pages).
 977 */
 978dma_cookie_t
 979dma_async_memcpy_pg_to_pg(struct dma_chan *chan, struct page *dest_pg,
 980        unsigned int dest_off, struct page *src_pg, unsigned int src_off,
 981        size_t len)
 982{
 983        struct dma_device *dev = chan->device;
 984        struct dma_async_tx_descriptor *tx;
 985        dma_addr_t dma_dest, dma_src;
 986        dma_cookie_t cookie;
 987        unsigned long flags;
 988
 989        dma_src = dma_map_page(dev->dev, src_pg, src_off, len, DMA_TO_DEVICE);
 990        dma_dest = dma_map_page(dev->dev, dest_pg, dest_off, len,
 991                                DMA_FROM_DEVICE);
 992        flags = DMA_CTRL_ACK;
 993        tx = dev->device_prep_dma_memcpy(chan, dma_dest, dma_src, len, flags);
 994
 995        if (!tx) {
 996                dma_unmap_page(dev->dev, dma_src, len, DMA_TO_DEVICE);
 997                dma_unmap_page(dev->dev, dma_dest, len, DMA_FROM_DEVICE);
 998                return -ENOMEM;
 999        }
1000
1001        tx->callback = NULL;
1002        cookie = tx->tx_submit(tx);
1003
1004        preempt_disable();
1005        __this_cpu_add(chan->local->bytes_transferred, len);
1006        __this_cpu_inc(chan->local->memcpy_count);
1007        preempt_enable();
1008
1009        return cookie;
1010}
1011EXPORT_SYMBOL(dma_async_memcpy_pg_to_pg);
1012
1013void dma_async_tx_descriptor_init(struct dma_async_tx_descriptor *tx,
1014        struct dma_chan *chan)
1015{
1016        tx->chan = chan;
1017        #ifdef CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH
1018        spin_lock_init(&tx->lock);
1019        #endif
1020}
1021EXPORT_SYMBOL(dma_async_tx_descriptor_init);
1022
1023/* dma_wait_for_async_tx - spin wait for a transaction to complete
1024 * @tx: in-flight transaction to wait on
1025 */
1026enum dma_status
1027dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx)
1028{
1029        unsigned long dma_sync_wait_timeout = jiffies + msecs_to_jiffies(5000);
1030
1031        if (!tx)
1032                return DMA_SUCCESS;
1033
1034        while (tx->cookie == -EBUSY) {
1035                if (time_after_eq(jiffies, dma_sync_wait_timeout)) {
1036                        pr_err("%s timeout waiting for descriptor submission\n",
1037                               __func__);
1038                        return DMA_ERROR;
1039                }
1040                cpu_relax();
1041        }
1042        return dma_sync_wait(tx->chan, tx->cookie);
1043}
1044EXPORT_SYMBOL_GPL(dma_wait_for_async_tx);
1045
1046/* dma_run_dependencies - helper routine for dma drivers to process
1047 *      (start) dependent operations on their target channel
1048 * @tx: transaction with dependencies
1049 */
1050void dma_run_dependencies(struct dma_async_tx_descriptor *tx)
1051{
1052        struct dma_async_tx_descriptor *dep = txd_next(tx);
1053        struct dma_async_tx_descriptor *dep_next;
1054        struct dma_chan *chan;
1055
1056        if (!dep)
1057                return;
1058
1059        /* we'll submit tx->next now, so clear the link */
1060        txd_clear_next(tx);
1061        chan = dep->chan;
1062
1063        /* keep submitting up until a channel switch is detected
1064         * in that case we will be called again as a result of
1065         * processing the interrupt from async_tx_channel_switch
1066         */
1067        for (; dep; dep = dep_next) {
1068                txd_lock(dep);
1069                txd_clear_parent(dep);
1070                dep_next = txd_next(dep);
1071                if (dep_next && dep_next->chan == chan)
1072                        txd_clear_next(dep); /* ->next will be submitted */
1073                else
1074                        dep_next = NULL; /* submit current dep and terminate */
1075                txd_unlock(dep);
1076
1077                dep->tx_submit(dep);
1078        }
1079
1080        chan->device->device_issue_pending(chan);
1081}
1082EXPORT_SYMBOL_GPL(dma_run_dependencies);
1083
1084static int __init dma_bus_init(void)
1085{
1086        return class_register(&dma_devclass);
1087}
1088arch_initcall(dma_bus_init);
1089
1090
1091
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