1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Copyright(c) 2004 - 2006 Intel Corporation. All rights reserved.
   4 */
   5
   6/*
   7 * This code implements the DMA subsystem. It provides a HW-neutral interface
   8 * for other kernel code to use asynchronous memory copy capabilities,
   9 * if present, and allows different HW DMA drivers to register as providing
  10 * this capability.
  11 *
  12 * Due to the fact we are accelerating what is already a relatively fast
  13 * operation, the code goes to great lengths to avoid additional overhead,
  14 * such as locking.
  15 *
  16 * LOCKING:
  17 *
  18 * The subsystem keeps a global list of dma_device structs it is protected by a
  19 * mutex, dma_list_mutex.
  20 *
  21 * A subsystem can get access to a channel by calling dmaengine_get() followed
  22 * by dma_find_channel(), or if it has need for an exclusive channel it can call
  23 * dma_request_channel().  Once a channel is allocated a reference is taken
  24 * against its corresponding driver to disable removal.
  25 *
  26 * Each device has a channels list, which runs unlocked but is never modified
  27 * once the device is registered, it's just setup by the driver.
  28 *
  29 * See Documentation/driver-api/dmaengine for more details
  30 */
  31
  32#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  33
  34#include <linux/platform_device.h>
  35#include <linux/dma-mapping.h>
  36#include <linux/init.h>
  37#include <linux/module.h>
  38#include <linux/mm.h>
  39#include <linux/device.h>
  40#include <linux/dmaengine.h>
  41#include <linux/hardirq.h>
  42#include <linux/spinlock.h>
  43#include <linux/percpu.h>
  44#include <linux/rcupdate.h>
  45#include <linux/mutex.h>
  46#include <linux/jiffies.h>
  47#include <linux/rculist.h>
  48#include <linux/idr.h>
  49#include <linux/slab.h>
  50#include <linux/acpi.h>
  51#include <linux/acpi_dma.h>
  52#include <linux/of_dma.h>
  53#include <linux/mempool.h>
  54#include <linux/numa.h>
  55
  56#include "dmaengine.h"
  57
  58static DEFINE_MUTEX(dma_list_mutex);
  59static DEFINE_IDA(dma_ida);
  60static LIST_HEAD(dma_device_list);
  61static long dmaengine_ref_count;
  62
  63/* --- debugfs implementation --- */
  64#ifdef CONFIG_DEBUG_FS
  65#include <linux/debugfs.h>
  66
  67static struct dentry *rootdir;
  68
  69static void dmaengine_debug_register(struct dma_device *dma_dev)
  70{
  71	dma_dev->dbg_dev_root = debugfs_create_dir(dev_name(dma_dev->dev),
  72						   rootdir);
  73	if (IS_ERR(dma_dev->dbg_dev_root))
  74		dma_dev->dbg_dev_root = NULL;
  75}
  76
  77static void dmaengine_debug_unregister(struct dma_device *dma_dev)
  78{
  79	debugfs_remove_recursive(dma_dev->dbg_dev_root);
  80	dma_dev->dbg_dev_root = NULL;
  81}
  82
  83static void dmaengine_dbg_summary_show(struct seq_file *s,
  84				       struct dma_device *dma_dev)
  85{
  86	struct dma_chan *chan;
  87
  88	list_for_each_entry(chan, &dma_dev->channels, device_node) {
  89		if (chan->client_count) {
  90			seq_printf(s, " %-13s| %s", dma_chan_name(chan),
  91				   chan->dbg_client_name ?: "in-use");
  92
  93			if (chan->router)
  94				seq_printf(s, " (via router: %s)\n",
  95					dev_name(chan->router->dev));
  96			else
  97				seq_puts(s, "\n");
  98		}
  99	}
 100}
 101
 102static int dmaengine_summary_show(struct seq_file *s, void *data)
 103{
 104	struct dma_device *dma_dev = NULL;
 105
 106	mutex_lock(&dma_list_mutex);
 107	list_for_each_entry(dma_dev, &dma_device_list, global_node) {
 108		seq_printf(s, "dma%d (%s): number of channels: %u\n",
 109			   dma_dev->dev_id, dev_name(dma_dev->dev),
 110			   dma_dev->chancnt);
 111
 112		if (dma_dev->dbg_summary_show)
 113			dma_dev->dbg_summary_show(s, dma_dev);
 114		else
 115			dmaengine_dbg_summary_show(s, dma_dev);
 116
 117		if (!list_is_last(&dma_dev->global_node, &dma_device_list))
 118			seq_puts(s, "\n");
 119	}
 120	mutex_unlock(&dma_list_mutex);
 121
 122	return 0;
 123}
 124DEFINE_SHOW_ATTRIBUTE(dmaengine_summary);
 125
 126static void __init dmaengine_debugfs_init(void)
 127{
 128	rootdir = debugfs_create_dir("dmaengine", NULL);
 129
 130	/* /sys/kernel/debug/dmaengine/summary */
 131	debugfs_create_file("summary", 0444, rootdir, NULL,
 132			    &dmaengine_summary_fops);
 133}
 134#else
 135static inline void dmaengine_debugfs_init(void) { }
 136static inline int dmaengine_debug_register(struct dma_device *dma_dev)
 137{
 138	return 0;
 139}
 140
 141static inline void dmaengine_debug_unregister(struct dma_device *dma_dev) { }
 142#endif	/* DEBUG_FS */
 143
 144/* --- sysfs implementation --- */
 145
 146#define DMA_SLAVE_NAME	"slave"
 147
 148/**
 149 * dev_to_dma_chan - convert a device pointer to its sysfs container object
 150 * @dev:	device node
 151 *
 152 * Must be called under dma_list_mutex.
 153 */
 154static struct dma_chan *dev_to_dma_chan(struct device *dev)
 155{
 156	struct dma_chan_dev *chan_dev;
 157
 158	chan_dev = container_of(dev, typeof(*chan_dev), device);
 159	return chan_dev->chan;
 160}
 161
 162static ssize_t memcpy_count_show(struct device *dev,
 163				 struct device_attribute *attr, char *buf)
 164{
 165	struct dma_chan *chan;
 166	unsigned long count = 0;
 167	int i;
 168	int err;
 169
 170	mutex_lock(&dma_list_mutex);
 171	chan = dev_to_dma_chan(dev);
 172	if (chan) {
 173		for_each_possible_cpu(i)
 174			count += per_cpu_ptr(chan->local, i)->memcpy_count;
 175		err = sysfs_emit(buf, "%lu\n", count);
 176	} else
 177		err = -ENODEV;
 178	mutex_unlock(&dma_list_mutex);
 179
 180	return err;
 181}
 182static DEVICE_ATTR_RO(memcpy_count);
 183
 184static ssize_t bytes_transferred_show(struct device *dev,
 185				      struct device_attribute *attr, char *buf)
 186{
 187	struct dma_chan *chan;
 188	unsigned long count = 0;
 189	int i;
 190	int err;
 191
 192	mutex_lock(&dma_list_mutex);
 193	chan = dev_to_dma_chan(dev);
 194	if (chan) {
 195		for_each_possible_cpu(i)
 196			count += per_cpu_ptr(chan->local, i)->bytes_transferred;
 197		err = sysfs_emit(buf, "%lu\n", count);
 198	} else
 199		err = -ENODEV;
 200	mutex_unlock(&dma_list_mutex);
 201
 202	return err;
 203}
 204static DEVICE_ATTR_RO(bytes_transferred);
 205
 206static ssize_t in_use_show(struct device *dev, struct device_attribute *attr,
 207			   char *buf)
 208{
 209	struct dma_chan *chan;
 210	int err;
 211
 212	mutex_lock(&dma_list_mutex);
 213	chan = dev_to_dma_chan(dev);
 214	if (chan)
 215		err = sysfs_emit(buf, "%d\n", chan->client_count);
 216	else
 217		err = -ENODEV;
 218	mutex_unlock(&dma_list_mutex);
 219
 220	return err;
 221}
 222static DEVICE_ATTR_RO(in_use);
 223
 224static struct attribute *dma_dev_attrs[] = {
 225	&dev_attr_memcpy_count.attr,
 226	&dev_attr_bytes_transferred.attr,
 227	&dev_attr_in_use.attr,
 228	NULL,
 229};
 230ATTRIBUTE_GROUPS(dma_dev);
 231
 232static void chan_dev_release(struct device *dev)
 233{
 234	struct dma_chan_dev *chan_dev;
 235
 236	chan_dev = container_of(dev, typeof(*chan_dev), device);
 237	kfree(chan_dev);
 238}
 239
 240static struct class dma_devclass = {
 241	.name		= "dma",
 242	.dev_groups	= dma_dev_groups,
 243	.dev_release	= chan_dev_release,
 244};
 245
 246/* --- client and device registration --- */
 247
 248/* enable iteration over all operation types */
 249static dma_cap_mask_t dma_cap_mask_all;
 250
 251/**
 252 * struct dma_chan_tbl_ent - tracks channel allocations per core/operation
 253 * @chan:	associated channel for this entry
 254 */
 255struct dma_chan_tbl_ent {
 256	struct dma_chan *chan;
 257};
 258
 259/* percpu lookup table for memory-to-memory offload providers */
 260static struct dma_chan_tbl_ent __percpu *channel_table[DMA_TX_TYPE_END];
 261
 262static int __init dma_channel_table_init(void)
 263{
 264	enum dma_transaction_type cap;
 265	int err = 0;
 266
 267	bitmap_fill(dma_cap_mask_all.bits, DMA_TX_TYPE_END);
 268
 269	/* 'interrupt', 'private', and 'slave' are channel capabilities,
 270	 * but are not associated with an operation so they do not need
 271	 * an entry in the channel_table
 272	 */
 273	clear_bit(DMA_INTERRUPT, dma_cap_mask_all.bits);
 274	clear_bit(DMA_PRIVATE, dma_cap_mask_all.bits);
 275	clear_bit(DMA_SLAVE, dma_cap_mask_all.bits);
 276
 277	for_each_dma_cap_mask(cap, dma_cap_mask_all) {
 278		channel_table[cap] = alloc_percpu(struct dma_chan_tbl_ent);
 279		if (!channel_table[cap]) {
 280			err = -ENOMEM;
 281			break;
 282		}
 283	}
 284
 285	if (err) {
 286		pr_err("dmaengine dma_channel_table_init failure: %d\n", err);
 287		for_each_dma_cap_mask(cap, dma_cap_mask_all)
 288			free_percpu(channel_table[cap]);
 289	}
 290
 291	return err;
 292}
 293arch_initcall(dma_channel_table_init);
 294
 295/**
 296 * dma_chan_is_local - checks if the channel is in the same NUMA-node as the CPU
 297 * @chan:	DMA channel to test
 298 * @cpu:	CPU index which the channel should be close to
 299 *
 300 * Returns true if the channel is in the same NUMA-node as the CPU.
 301 */
 302static bool dma_chan_is_local(struct dma_chan *chan, int cpu)
 303{
 304	int node = dev_to_node(chan->device->dev);
 305	return node == NUMA_NO_NODE ||
 306		cpumask_test_cpu(cpu, cpumask_of_node(node));
 307}
 308
 309/**
 310 * min_chan - finds the channel with min count and in the same NUMA-node as the CPU
 311 * @cap:	capability to match
 312 * @cpu:	CPU index which the channel should be close to
 313 *
 314 * If some channels are close to the given CPU, the one with the lowest
 315 * reference count is returned. Otherwise, CPU is ignored and only the
 316 * reference count is taken into account.
 317 *
 318 * Must be called under dma_list_mutex.
 319 */
 320static struct dma_chan *min_chan(enum dma_transaction_type cap, int cpu)
 321{
 322	struct dma_device *device;
 323	struct dma_chan *chan;
 324	struct dma_chan *min = NULL;
 325	struct dma_chan *localmin = NULL;
 326
 327	list_for_each_entry(device, &dma_device_list, global_node) {
 328		if (!dma_has_cap(cap, device->cap_mask) ||
 329		    dma_has_cap(DMA_PRIVATE, device->cap_mask))
 330			continue;
 331		list_for_each_entry(chan, &device->channels, device_node) {
 332			if (!chan->client_count)
 333				continue;
 334			if (!min || chan->table_count < min->table_count)
 335				min = chan;
 336
 337			if (dma_chan_is_local(chan, cpu))
 338				if (!localmin ||
 339				    chan->table_count < localmin->table_count)
 340					localmin = chan;
 341		}
 342	}
 343
 344	chan = localmin ? localmin : min;
 345
 346	if (chan)
 347		chan->table_count++;
 348
 349	return chan;
 350}
 351
 352/**
 353 * dma_channel_rebalance - redistribute the available channels
 354 *
 355 * Optimize for CPU isolation (each CPU gets a dedicated channel for an
 356 * operation type) in the SMP case, and operation isolation (avoid
 357 * multi-tasking channels) in the non-SMP case.
 358 *
 359 * Must be called under dma_list_mutex.
 360 */
 361static void dma_channel_rebalance(void)
 362{
 363	struct dma_chan *chan;
 364	struct dma_device *device;
 365	int cpu;
 366	int cap;
 367
 368	/* undo the last distribution */
 369	for_each_dma_cap_mask(cap, dma_cap_mask_all)
 370		for_each_possible_cpu(cpu)
 371			per_cpu_ptr(channel_table[cap], cpu)->chan = NULL;
 372
 373	list_for_each_entry(device, &dma_device_list, global_node) {
 374		if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
 375			continue;
 376		list_for_each_entry(chan, &device->channels, device_node)
 377			chan->table_count = 0;
 378	}
 379
 380	/* don't populate the channel_table if no clients are available */
 381	if (!dmaengine_ref_count)
 382		return;
 383
 384	/* redistribute available channels */
 385	for_each_dma_cap_mask(cap, dma_cap_mask_all)
 386		for_each_online_cpu(cpu) {
 387			chan = min_chan(cap, cpu);
 388			per_cpu_ptr(channel_table[cap], cpu)->chan = chan;
 389		}
 390}
 391
 392static int dma_device_satisfies_mask(struct dma_device *device,
 393				     const dma_cap_mask_t *want)
 394{
 395	dma_cap_mask_t has;
 396
 397	bitmap_and(has.bits, want->bits, device->cap_mask.bits,
 398		DMA_TX_TYPE_END);
 399	return bitmap_equal(want->bits, has.bits, DMA_TX_TYPE_END);
 400}
 401
 402static struct module *dma_chan_to_owner(struct dma_chan *chan)
 403{
 404	return chan->device->owner;
 405}
 406
 407/**
 408 * balance_ref_count - catch up the channel reference count
 409 * @chan:	channel to balance ->client_count versus dmaengine_ref_count
 410 *
 411 * Must be called under dma_list_mutex.
 412 */
 413static void balance_ref_count(struct dma_chan *chan)
 414{
 415	struct module *owner = dma_chan_to_owner(chan);
 416
 417	while (chan->client_count < dmaengine_ref_count) {
 418		__module_get(owner);
 419		chan->client_count++;
 420	}
 421}
 422
 423static void dma_device_release(struct kref *ref)
 424{
 425	struct dma_device *device = container_of(ref, struct dma_device, ref);
 426
 427	list_del_rcu(&device->global_node);
 428	dma_channel_rebalance();
 429
 430	if (device->device_release)
 431		device->device_release(device);
 432}
 433
 434static void dma_device_put(struct dma_device *device)
 435{
 436	lockdep_assert_held(&dma_list_mutex);
 437	kref_put(&device->ref, dma_device_release);
 438}
 439
 440/**
 441 * dma_chan_get - try to grab a DMA channel's parent driver module
 442 * @chan:	channel to grab
 443 *
 444 * Must be called under dma_list_mutex.
 445 */
 446static int dma_chan_get(struct dma_chan *chan)
 447{
 448	struct module *owner = dma_chan_to_owner(chan);
 449	int ret;
 450
 451	/* The channel is already in use, update client count */
 452	if (chan->client_count) {
 453		__module_get(owner);
 454		chan->client_count++;
 455		return 0;
 456	}
 457
 458	if (!try_module_get(owner))
 459		return -ENODEV;
 460
 461	ret = kref_get_unless_zero(&chan->device->ref);
 462	if (!ret) {
 463		ret = -ENODEV;
 464		goto module_put_out;
 465	}
 466
 467	/* allocate upon first client reference */
 468	if (chan->device->device_alloc_chan_resources) {
 469		ret = chan->device->device_alloc_chan_resources(chan);
 470		if (ret < 0)
 471			goto err_out;
 472	}
 473
 474	chan->client_count++;
 475
 476	if (!dma_has_cap(DMA_PRIVATE, chan->device->cap_mask))
 477		balance_ref_count(chan);
 478
 479	return 0;
 480
 481err_out:
 482	dma_device_put(chan->device);
 483module_put_out:
 484	module_put(owner);
 485	return ret;
 486}
 487
 488/**
 489 * dma_chan_put - drop a reference to a DMA channel's parent driver module
 490 * @chan:	channel to release
 491 *
 492 * Must be called under dma_list_mutex.
 493 */
 494static void dma_chan_put(struct dma_chan *chan)
 495{
 496	/* This channel is not in use, bail out */
 497	if (!chan->client_count)
 498		return;
 499
 500	chan->client_count--;
 501
 502	/* This channel is not in use anymore, free it */
 503	if (!chan->client_count && chan->device->device_free_chan_resources) {
 504		/* Make sure all operations have completed */
 505		dmaengine_synchronize(chan);
 506		chan->device->device_free_chan_resources(chan);
 507	}
 508
 509	/* If the channel is used via a DMA request router, free the mapping */
 510	if (chan->router && chan->router->route_free) {
 511		chan->router->route_free(chan->router->dev, chan->route_data);
 512		chan->router = NULL;
 513		chan->route_data = NULL;
 514	}
 515
 516	dma_device_put(chan->device);
 517	module_put(dma_chan_to_owner(chan));
 518}
 519
 520enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie)
 521{
 522	enum dma_status status;
 523	unsigned long dma_sync_wait_timeout = jiffies + msecs_to_jiffies(5000);
 524
 525	dma_async_issue_pending(chan);
 526	do {
 527		status = dma_async_is_tx_complete(chan, cookie, NULL, NULL);
 528		if (time_after_eq(jiffies, dma_sync_wait_timeout)) {
 529			dev_err(chan->device->dev, "%s: timeout!\n", __func__);
 530			return DMA_ERROR;
 531		}
 532		if (status != DMA_IN_PROGRESS)
 533			break;
 534		cpu_relax();
 535	} while (1);
 536
 537	return status;
 538}
 539EXPORT_SYMBOL(dma_sync_wait);
 540
 541/**
 542 * dma_find_channel - find a channel to carry out the operation
 543 * @tx_type:	transaction type
 544 */
 545struct dma_chan *dma_find_channel(enum dma_transaction_type tx_type)
 546{
 547	return this_cpu_read(channel_table[tx_type]->chan);
 548}
 549EXPORT_SYMBOL(dma_find_channel);
 550
 551/**
 552 * dma_issue_pending_all - flush all pending operations across all channels
 553 */
 554void dma_issue_pending_all(void)
 555{
 556	struct dma_device *device;
 557	struct dma_chan *chan;
 558
 559	rcu_read_lock();
 560	list_for_each_entry_rcu(device, &dma_device_list, global_node) {
 561		if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
 562			continue;
 563		list_for_each_entry(chan, &device->channels, device_node)
 564			if (chan->client_count)
 565				device->device_issue_pending(chan);
 566	}
 567	rcu_read_unlock();
 568}
 569EXPORT_SYMBOL(dma_issue_pending_all);
 570
 571int dma_get_slave_caps(struct dma_chan *chan, struct dma_slave_caps *caps)
 572{
 573	struct dma_device *device;
 574
 575	if (!chan || !caps)
 576		return -EINVAL;
 577
 578	device = chan->device;
 579
 580	/* check if the channel supports slave transactions */
 581	if (!(test_bit(DMA_SLAVE, device->cap_mask.bits) ||
 582	      test_bit(DMA_CYCLIC, device->cap_mask.bits)))
 583		return -ENXIO;
 584
 585	/*
 586	 * Check whether it reports it uses the generic slave
 587	 * capabilities, if not, that means it doesn't support any
 588	 * kind of slave capabilities reporting.
 589	 */
 590	if (!device->directions)
 591		return -ENXIO;
 592
 593	caps->src_addr_widths = device->src_addr_widths;
 594	caps->dst_addr_widths = device->dst_addr_widths;
 595	caps->directions = device->directions;
 596	caps->min_burst = device->min_burst;
 597	caps->max_burst = device->max_burst;
 598	caps->max_sg_burst = device->max_sg_burst;
 599	caps->residue_granularity = device->residue_granularity;
 600	caps->descriptor_reuse = device->descriptor_reuse;
 601	caps->cmd_pause = !!device->device_pause;
 602	caps->cmd_resume = !!device->device_resume;
 603	caps->cmd_terminate = !!device->device_terminate_all;
 604
 605	/*
 606	 * DMA engine device might be configured with non-uniformly
 607	 * distributed slave capabilities per device channels. In this
 608	 * case the corresponding driver may provide the device_caps
 609	 * callback to override the generic capabilities with
 610	 * channel-specific ones.
 611	 */
 612	if (device->device_caps)
 613		device->device_caps(chan, caps);
 614
 615	return 0;
 616}
 617EXPORT_SYMBOL_GPL(dma_get_slave_caps);
 618
 619static struct dma_chan *private_candidate(const dma_cap_mask_t *mask,
 620					  struct dma_device *dev,
 621					  dma_filter_fn fn, void *fn_param)
 622{
 623	struct dma_chan *chan;
 624
 625	if (mask && !dma_device_satisfies_mask(dev, mask)) {
 626		dev_dbg(dev->dev, "%s: wrong capabilities\n", __func__);
 627		return NULL;
 628	}
 629	/* devices with multiple channels need special handling as we need to
 630	 * ensure that all channels are either private or public.
 631	 */
 632	if (dev->chancnt > 1 && !dma_has_cap(DMA_PRIVATE, dev->cap_mask))
 633		list_for_each_entry(chan, &dev->channels, device_node) {
 634			/* some channels are already publicly allocated */
 635			if (chan->client_count)
 636				return NULL;
 637		}
 638
 639	list_for_each_entry(chan, &dev->channels, device_node) {
 640		if (chan->client_count) {
 641			dev_dbg(dev->dev, "%s: %s busy\n",
 642				 __func__, dma_chan_name(chan));
 643			continue;
 644		}
 645		if (fn && !fn(chan, fn_param)) {
 646			dev_dbg(dev->dev, "%s: %s filter said false\n",
 647				 __func__, dma_chan_name(chan));
 648			continue;
 649		}
 650		return chan;
 651	}
 652
 653	return NULL;
 654}
 655
 656static struct dma_chan *find_candidate(struct dma_device *device,
 657				       const dma_cap_mask_t *mask,
 658				       dma_filter_fn fn, void *fn_param)
 659{
 660	struct dma_chan *chan = private_candidate(mask, device, fn, fn_param);
 661	int err;
 662
 663	if (chan) {
 664		/* Found a suitable channel, try to grab, prep, and return it.
 665		 * We first set DMA_PRIVATE to disable balance_ref_count as this
 666		 * channel will not be published in the general-purpose
 667		 * allocator
 668		 */
 669		dma_cap_set(DMA_PRIVATE, device->cap_mask);
 670		device->privatecnt++;
 671		err = dma_chan_get(chan);
 672
 673		if (err) {
 674			if (err == -ENODEV) {
 675				dev_dbg(device->dev, "%s: %s module removed\n",
 676					__func__, dma_chan_name(chan));
 677				list_del_rcu(&device->global_node);
 678			} else
 679				dev_dbg(device->dev,
 680					"%s: failed to get %s: (%d)\n",
 681					 __func__, dma_chan_name(chan), err);
 682
 683			if (--device->privatecnt == 0)
 684				dma_cap_clear(DMA_PRIVATE, device->cap_mask);
 685
 686			chan = ERR_PTR(err);
 687		}
 688	}
 689
 690	return chan ? chan : ERR_PTR(-EPROBE_DEFER);
 691}
 692
 693/**
 694 * dma_get_slave_channel - try to get specific channel exclusively
 695 * @chan:	target channel
 696 */
 697struct dma_chan *dma_get_slave_channel(struct dma_chan *chan)
 698{
 699	/* lock against __dma_request_channel */
 700	mutex_lock(&dma_list_mutex);
 701
 702	if (chan->client_count == 0) {
 703		struct dma_device *device = chan->device;
 704		int err;
 705
 706		dma_cap_set(DMA_PRIVATE, device->cap_mask);
 707		device->privatecnt++;
 708		err = dma_chan_get(chan);
 709		if (err) {
 710			dev_dbg(chan->device->dev,
 711				"%s: failed to get %s: (%d)\n",
 712				__func__, dma_chan_name(chan), err);
 713			chan = NULL;
 714			if (--device->privatecnt == 0)
 715				dma_cap_clear(DMA_PRIVATE, device->cap_mask);
 716		}
 717	} else
 718		chan = NULL;
 719
 720	mutex_unlock(&dma_list_mutex);
 721
 722
 723	return chan;
 724}
 725EXPORT_SYMBOL_GPL(dma_get_slave_channel);
 726
 727struct dma_chan *dma_get_any_slave_channel(struct dma_device *device)
 728{
 729	dma_cap_mask_t mask;
 730	struct dma_chan *chan;
 731
 732	dma_cap_zero(mask);
 733	dma_cap_set(DMA_SLAVE, mask);
 734
 735	/* lock against __dma_request_channel */
 736	mutex_lock(&dma_list_mutex);
 737
 738	chan = find_candidate(device, &mask, NULL, NULL);
 739
 740	mutex_unlock(&dma_list_mutex);
 741
 742	return IS_ERR(chan) ? NULL : chan;
 743}
 744EXPORT_SYMBOL_GPL(dma_get_any_slave_channel);
 745
 746/**
 747 * __dma_request_channel - try to allocate an exclusive channel
 748 * @mask:	capabilities that the channel must satisfy
 749 * @fn:		optional callback to disposition available channels
 750 * @fn_param:	opaque parameter to pass to dma_filter_fn()
 751 * @np:		device node to look for DMA channels
 752 *
 753 * Returns pointer to appropriate DMA channel on success or NULL.
 754 */
 755struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
 756				       dma_filter_fn fn, void *fn_param,
 757				       struct device_node *np)
 758{
 759	struct dma_device *device, *_d;
 760	struct dma_chan *chan = NULL;
 761
 762	/* Find a channel */
 763	mutex_lock(&dma_list_mutex);
 764	list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
 765		/* Finds a DMA controller with matching device node */
 766		if (np && device->dev->of_node && np != device->dev->of_node)
 767			continue;
 768
 769		chan = find_candidate(device, mask, fn, fn_param);
 770		if (!IS_ERR(chan))
 771			break;
 772
 773		chan = NULL;
 774	}
 775	mutex_unlock(&dma_list_mutex);
 776
 777	pr_debug("%s: %s (%s)\n",
 778		 __func__,
 779		 chan ? "success" : "fail",
 780		 chan ? dma_chan_name(chan) : NULL);
 781
 782	return chan;
 783}
 784EXPORT_SYMBOL_GPL(__dma_request_channel);
 785
 786static const struct dma_slave_map *dma_filter_match(struct dma_device *device,
 787						    const char *name,
 788						    struct device *dev)
 789{
 790	int i;
 791
 792	if (!device->filter.mapcnt)
 793		return NULL;
 794
 795	for (i = 0; i < device->filter.mapcnt; i++) {
 796		const struct dma_slave_map *map = &device->filter.map[i];
 797
 798		if (!strcmp(map->devname, dev_name(dev)) &&
 799		    !strcmp(map->slave, name))
 800			return map;
 801	}
 802
 803	return NULL;
 804}
 805
 806/**
 807 * dma_request_chan - try to allocate an exclusive slave channel
 808 * @dev:	pointer to client device structure
 809 * @name:	slave channel name
 810 *
 811 * Returns pointer to appropriate DMA channel on success or an error pointer.
 812 */
 813struct dma_chan *dma_request_chan(struct device *dev, const char *name)
 814{
 815	struct dma_device *d, *_d;
 816	struct dma_chan *chan = NULL;
 817
 818	/* If device-tree is present get slave info from here */
 819	if (dev->of_node)
 820		chan = of_dma_request_slave_channel(dev->of_node, name);
 821
 822	/* If device was enumerated by ACPI get slave info from here */
 823	if (has_acpi_companion(dev) && !chan)
 824		chan = acpi_dma_request_slave_chan_by_name(dev, name);
 825
 826	if (PTR_ERR(chan) == -EPROBE_DEFER)
 827		return chan;
 828
 829	if (!IS_ERR_OR_NULL(chan))
 830		goto found;
 831
 832	/* Try to find the channel via the DMA filter map(s) */
 833	mutex_lock(&dma_list_mutex);
 834	list_for_each_entry_safe(d, _d, &dma_device_list, global_node) {
 835		dma_cap_mask_t mask;
 836		const struct dma_slave_map *map = dma_filter_match(d, name, dev);
 837
 838		if (!map)
 839			continue;
 840
 841		dma_cap_zero(mask);
 842		dma_cap_set(DMA_SLAVE, mask);
 843
 844		chan = find_candidate(d, &mask, d->filter.fn, map->param);
 845		if (!IS_ERR(chan))
 846			break;
 847	}
 848	mutex_unlock(&dma_list_mutex);
 849
 850	if (IS_ERR(chan))
 851		return chan;
 852	if (!chan)
 853		return ERR_PTR(-EPROBE_DEFER);
 854
 855found:
 856#ifdef CONFIG_DEBUG_FS
 857	chan->dbg_client_name = kasprintf(GFP_KERNEL, "%s:%s", dev_name(dev),
 858					  name);
 859#endif
 860
 861	chan->name = kasprintf(GFP_KERNEL, "dma:%s", name);
 862	if (!chan->name)
 863		return chan;
 864	chan->slave = dev;
 865
 866	if (sysfs_create_link(&chan->dev->device.kobj, &dev->kobj,
 867			      DMA_SLAVE_NAME))
 868		dev_warn(dev, "Cannot create DMA %s symlink\n", DMA_SLAVE_NAME);
 869	if (sysfs_create_link(&dev->kobj, &chan->dev->device.kobj, chan->name))
 870		dev_warn(dev, "Cannot create DMA %s symlink\n", chan->name);
 871
 872	return chan;
 873}
 874EXPORT_SYMBOL_GPL(dma_request_chan);
 875
 876/**
 877 * dma_request_chan_by_mask - allocate a channel satisfying certain capabilities
 878 * @mask:	capabilities that the channel must satisfy
 879 *
 880 * Returns pointer to appropriate DMA channel on success or an error pointer.
 881 */
 882struct dma_chan *dma_request_chan_by_mask(const dma_cap_mask_t *mask)
 883{
 884	struct dma_chan *chan;
 885
 886	if (!mask)
 887		return ERR_PTR(-ENODEV);
 888
 889	chan = __dma_request_channel(mask, NULL, NULL, NULL);
 890	if (!chan) {
 891		mutex_lock(&dma_list_mutex);
 892		if (list_empty(&dma_device_list))
 893			chan = ERR_PTR(-EPROBE_DEFER);
 894		else
 895			chan = ERR_PTR(-ENODEV);
 896		mutex_unlock(&dma_list_mutex);
 897	}
 898
 899	return chan;
 900}
 901EXPORT_SYMBOL_GPL(dma_request_chan_by_mask);
 902
 903void dma_release_channel(struct dma_chan *chan)
 904{
 905	mutex_lock(&dma_list_mutex);
 906	WARN_ONCE(chan->client_count != 1,
 907		  "chan reference count %d != 1\n", chan->client_count);
 908	dma_chan_put(chan);
 909	/* drop PRIVATE cap enabled by __dma_request_channel() */
 910	if (--chan->device->privatecnt == 0)
 911		dma_cap_clear(DMA_PRIVATE, chan->device->cap_mask);
 912
 913	if (chan->slave) {
 914		sysfs_remove_link(&chan->dev->device.kobj, DMA_SLAVE_NAME);
 915		sysfs_remove_link(&chan->slave->kobj, chan->name);
 916		kfree(chan->name);
 917		chan->name = NULL;
 918		chan->slave = NULL;
 919	}
 920
 921#ifdef CONFIG_DEBUG_FS
 922	kfree(chan->dbg_client_name);
 923	chan->dbg_client_name = NULL;
 924#endif
 925	mutex_unlock(&dma_list_mutex);
 926}
 927EXPORT_SYMBOL_GPL(dma_release_channel);
 928
 929/**
 930 * dmaengine_get - register interest in dma_channels
 931 */
 932void dmaengine_get(void)
 933{
 934	struct dma_device *device, *_d;
 935	struct dma_chan *chan;
 936	int err;
 937
 938	mutex_lock(&dma_list_mutex);
 939	dmaengine_ref_count++;
 940
 941	/* try to grab channels */
 942	list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
 943		if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
 944			continue;
 945		list_for_each_entry(chan, &device->channels, device_node) {
 946			err = dma_chan_get(chan);
 947			if (err == -ENODEV) {
 948				/* module removed before we could use it */
 949				list_del_rcu(&device->global_node);
 950				break;
 951			} else if (err)
 952				dev_dbg(chan->device->dev,
 953					"%s: failed to get %s: (%d)\n",
 954					__func__, dma_chan_name(chan), err);
 955		}
 956	}
 957
 958	/* if this is the first reference and there were channels
 959	 * waiting we need to rebalance to get those channels
 960	 * incorporated into the channel table
 961	 */
 962	if (dmaengine_ref_count == 1)
 963		dma_channel_rebalance();
 964	mutex_unlock(&dma_list_mutex);
 965}
 966EXPORT_SYMBOL(dmaengine_get);
 967
 968/**
 969 * dmaengine_put - let DMA drivers be removed when ref_count == 0
 970 */
 971void dmaengine_put(void)
 972{
 973	struct dma_device *device, *_d;
 974	struct dma_chan *chan;
 975
 976	mutex_lock(&dma_list_mutex);
 977	dmaengine_ref_count--;
 978	BUG_ON(dmaengine_ref_count < 0);
 979	/* drop channel references */
 980	list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
 981		if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
 982			continue;
 983		list_for_each_entry(chan, &device->channels, device_node)
 984			dma_chan_put(chan);
 985	}
 986	mutex_unlock(&dma_list_mutex);
 987}
 988EXPORT_SYMBOL(dmaengine_put);
 989
 990static bool device_has_all_tx_types(struct dma_device *device)
 991{
 992	/* A device that satisfies this test has channels that will never cause
 993	 * an async_tx channel switch event as all possible operation types can
 994	 * be handled.
 995	 */
 996	#ifdef CONFIG_ASYNC_TX_DMA
 997	if (!dma_has_cap(DMA_INTERRUPT, device->cap_mask))
 998		return false;
 999	#endif
1000
1001	#if IS_ENABLED(CONFIG_ASYNC_MEMCPY)
1002	if (!dma_has_cap(DMA_MEMCPY, device->cap_mask))
1003		return false;
1004	#endif
1005
1006	#if IS_ENABLED(CONFIG_ASYNC_XOR)
1007	if (!dma_has_cap(DMA_XOR, device->cap_mask))
1008		return false;
1009
1010	#ifndef CONFIG_ASYNC_TX_DISABLE_XOR_VAL_DMA
1011	if (!dma_has_cap(DMA_XOR_VAL, device->cap_mask))
1012		return false;
1013	#endif
1014	#endif
1015
1016	#if IS_ENABLED(CONFIG_ASYNC_PQ)
1017	if (!dma_has_cap(DMA_PQ, device->cap_mask))
1018		return false;
1019
1020	#ifndef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA
1021	if (!dma_has_cap(DMA_PQ_VAL, device->cap_mask))
1022		return false;
1023	#endif
1024	#endif
1025
1026	return true;
1027}
1028
1029static int get_dma_id(struct dma_device *device)
1030{
1031	int rc = ida_alloc(&dma_ida, GFP_KERNEL);
1032
1033	if (rc < 0)
1034		return rc;
1035	device->dev_id = rc;
1036	return 0;
1037}
1038
1039static int __dma_async_device_channel_register(struct dma_device *device,
1040					       struct dma_chan *chan)
 
1041{
1042	int rc;
1043
1044	chan->local = alloc_percpu(typeof(*chan->local));
1045	if (!chan->local)
1046		return -ENOMEM;
1047	chan->dev = kzalloc(sizeof(*chan->dev), GFP_KERNEL);
1048	if (!chan->dev) {
1049		rc = -ENOMEM;
1050		goto err_free_local;
1051	}
1052
1053	/*
1054	 * When the chan_id is a negative value, we are dynamically adding
1055	 * the channel. Otherwise we are static enumerating.
1056	 */
1057	chan->chan_id = ida_alloc(&device->chan_ida, GFP_KERNEL);
1058	if (chan->chan_id < 0) {
1059		pr_err("%s: unable to alloc ida for chan: %d\n",
1060		       __func__, chan->chan_id);
1061		rc = chan->chan_id;
1062		goto err_free_dev;
1063	}
1064
1065	chan->dev->device.class = &dma_devclass;
1066	chan->dev->device.parent = device->dev;
1067	chan->dev->chan = chan;
1068	chan->dev->dev_id = device->dev_id;
1069	dev_set_name(&chan->dev->device, "dma%dchan%d",
1070		     device->dev_id, chan->chan_id);
 
 
1071	rc = device_register(&chan->dev->device);
1072	if (rc)
1073		goto err_out_ida;
1074	chan->client_count = 0;
1075	device->chancnt++;
1076
1077	return 0;
1078
1079 err_out_ida:
1080	ida_free(&device->chan_ida, chan->chan_id);
1081 err_free_dev:
1082	kfree(chan->dev);
1083 err_free_local:
1084	free_percpu(chan->local);
1085	chan->local = NULL;
1086	return rc;
1087}
1088
1089int dma_async_device_channel_register(struct dma_device *device,
1090				      struct dma_chan *chan)
 
1091{
1092	int rc;
1093
1094	rc = __dma_async_device_channel_register(device, chan);
1095	if (rc < 0)
1096		return rc;
1097
1098	dma_channel_rebalance();
1099	return 0;
1100}
1101EXPORT_SYMBOL_GPL(dma_async_device_channel_register);
1102
1103static void __dma_async_device_channel_unregister(struct dma_device *device,
1104						  struct dma_chan *chan)
1105{
1106	if (chan->local == NULL)
1107		return;
1108
1109	WARN_ONCE(!device->device_release && chan->client_count,
1110		  "%s called while %d clients hold a reference\n",
1111		  __func__, chan->client_count);
1112	mutex_lock(&dma_list_mutex);
1113	device->chancnt--;
1114	chan->dev->chan = NULL;
1115	mutex_unlock(&dma_list_mutex);
1116	ida_free(&device->chan_ida, chan->chan_id);
1117	device_unregister(&chan->dev->device);
1118	free_percpu(chan->local);
1119}
1120
1121void dma_async_device_channel_unregister(struct dma_device *device,
1122					 struct dma_chan *chan)
1123{
1124	__dma_async_device_channel_unregister(device, chan);
1125	dma_channel_rebalance();
1126}
1127EXPORT_SYMBOL_GPL(dma_async_device_channel_unregister);
1128
1129/**
1130 * dma_async_device_register - registers DMA devices found
1131 * @device:	pointer to &struct dma_device
1132 *
1133 * After calling this routine the structure should not be freed except in the
1134 * device_release() callback which will be called after
1135 * dma_async_device_unregister() is called and no further references are taken.
1136 */
1137int dma_async_device_register(struct dma_device *device)
1138{
1139	int rc;
1140	struct dma_chan* chan;
1141
1142	if (!device)
1143		return -ENODEV;
1144
1145	/* validate device routines */
1146	if (!device->dev) {
1147		pr_err("DMAdevice must have dev\n");
1148		return -EIO;
1149	}
1150
1151	device->owner = device->dev->driver->owner;
1152
1153#define CHECK_CAP(_name, _type)								\
1154{											\
1155	if (dma_has_cap(_type, device->cap_mask) && !device->device_prep_##_name) {	\
1156		dev_err(device->dev,							\
1157			"Device claims capability %s, but op is not defined\n",		\
1158			__stringify(_type));						\
1159		return -EIO;								\
1160	}										\
1161}
1162
1163	CHECK_CAP(dma_memcpy,      DMA_MEMCPY);
1164	CHECK_CAP(dma_xor,         DMA_XOR);
1165	CHECK_CAP(dma_xor_val,     DMA_XOR_VAL);
1166	CHECK_CAP(dma_pq,          DMA_PQ);
1167	CHECK_CAP(dma_pq_val,      DMA_PQ_VAL);
1168	CHECK_CAP(dma_memset,      DMA_MEMSET);
1169	CHECK_CAP(dma_interrupt,   DMA_INTERRUPT);
1170	CHECK_CAP(dma_cyclic,      DMA_CYCLIC);
1171	CHECK_CAP(interleaved_dma, DMA_INTERLEAVE);
1172
1173#undef CHECK_CAP
1174
1175	if (!device->device_tx_status) {
1176		dev_err(device->dev, "Device tx_status is not defined\n");
1177		return -EIO;
1178	}
1179
1180
1181	if (!device->device_issue_pending) {
1182		dev_err(device->dev, "Device issue_pending is not defined\n");
1183		return -EIO;
1184	}
1185
1186	if (!device->device_release)
1187		dev_dbg(device->dev,
1188			 "WARN: Device release is not defined so it is not safe to unbind this driver while in use\n");
1189
1190	kref_init(&device->ref);
1191
1192	/* note: this only matters in the
1193	 * CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH=n case
1194	 */
1195	if (device_has_all_tx_types(device))
1196		dma_cap_set(DMA_ASYNC_TX, device->cap_mask);
1197
1198	rc = get_dma_id(device);
1199	if (rc != 0)
1200		return rc;
1201
1202	ida_init(&device->chan_ida);
1203
1204	/* represent channels in sysfs. Probably want devs too */
1205	list_for_each_entry(chan, &device->channels, device_node) {
1206		rc = __dma_async_device_channel_register(device, chan);
1207		if (rc < 0)
1208			goto err_out;
1209	}
1210
1211	mutex_lock(&dma_list_mutex);
1212	/* take references on public channels */
1213	if (dmaengine_ref_count && !dma_has_cap(DMA_PRIVATE, device->cap_mask))
1214		list_for_each_entry(chan, &device->channels, device_node) {
1215			/* if clients are already waiting for channels we need
1216			 * to take references on their behalf
1217			 */
1218			if (dma_chan_get(chan) == -ENODEV) {
1219				/* note we can only get here for the first
1220				 * channel as the remaining channels are
1221				 * guaranteed to get a reference
1222				 */
1223				rc = -ENODEV;
1224				mutex_unlock(&dma_list_mutex);
1225				goto err_out;
1226			}
1227		}
1228	list_add_tail_rcu(&device->global_node, &dma_device_list);
1229	if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
1230		device->privatecnt++;	/* Always private */
1231	dma_channel_rebalance();
1232	mutex_unlock(&dma_list_mutex);
1233
1234	dmaengine_debug_register(device);
1235
1236	return 0;
1237
1238err_out:
1239	/* if we never registered a channel just release the idr */
1240	if (!device->chancnt) {
1241		ida_free(&dma_ida, device->dev_id);
1242		return rc;
1243	}
1244
1245	list_for_each_entry(chan, &device->channels, device_node) {
1246		if (chan->local == NULL)
1247			continue;
1248		mutex_lock(&dma_list_mutex);
1249		chan->dev->chan = NULL;
1250		mutex_unlock(&dma_list_mutex);
1251		device_unregister(&chan->dev->device);
1252		free_percpu(chan->local);
1253	}
1254	return rc;
1255}
1256EXPORT_SYMBOL(dma_async_device_register);
1257
1258/**
1259 * dma_async_device_unregister - unregister a DMA device
1260 * @device:	pointer to &struct dma_device
1261 *
1262 * This routine is called by dma driver exit routines, dmaengine holds module
1263 * references to prevent it being called while channels are in use.
1264 */
1265void dma_async_device_unregister(struct dma_device *device)
1266{
1267	struct dma_chan *chan, *n;
1268
1269	dmaengine_debug_unregister(device);
1270
1271	list_for_each_entry_safe(chan, n, &device->channels, device_node)
1272		__dma_async_device_channel_unregister(device, chan);
1273
1274	mutex_lock(&dma_list_mutex);
1275	/*
1276	 * setting DMA_PRIVATE ensures the device being torn down will not
1277	 * be used in the channel_table
1278	 */
1279	dma_cap_set(DMA_PRIVATE, device->cap_mask);
1280	dma_channel_rebalance();
1281	ida_free(&dma_ida, device->dev_id);
1282	dma_device_put(device);
1283	mutex_unlock(&dma_list_mutex);
1284}
1285EXPORT_SYMBOL(dma_async_device_unregister);
1286
1287static void dmaenginem_async_device_unregister(void *device)
1288{
1289	dma_async_device_unregister(device);
1290}
1291
1292/**
1293 * dmaenginem_async_device_register - registers DMA devices found
1294 * @device:	pointer to &struct dma_device
1295 *
1296 * The operation is managed and will be undone on driver detach.
1297 */
1298int dmaenginem_async_device_register(struct dma_device *device)
1299{
1300	int ret;
1301
1302	ret = dma_async_device_register(device);
1303	if (ret)
1304		return ret;
1305
1306	return devm_add_action_or_reset(device->dev, dmaenginem_async_device_unregister, device);
1307}
1308EXPORT_SYMBOL(dmaenginem_async_device_register);
1309
1310struct dmaengine_unmap_pool {
1311	struct kmem_cache *cache;
1312	const char *name;
1313	mempool_t *pool;
1314	size_t size;
1315};
1316
1317#define __UNMAP_POOL(x) { .size = x, .name = "dmaengine-unmap-" __stringify(x) }
1318static struct dmaengine_unmap_pool unmap_pool[] = {
1319	__UNMAP_POOL(2),
1320	#if IS_ENABLED(CONFIG_DMA_ENGINE_RAID)
1321	__UNMAP_POOL(16),
1322	__UNMAP_POOL(128),
1323	__UNMAP_POOL(256),
1324	#endif
1325};
1326
1327static struct dmaengine_unmap_pool *__get_unmap_pool(int nr)
1328{
1329	int order = get_count_order(nr);
1330
1331	switch (order) {
1332	case 0 ... 1:
1333		return &unmap_pool[0];
1334#if IS_ENABLED(CONFIG_DMA_ENGINE_RAID)
1335	case 2 ... 4:
1336		return &unmap_pool[1];
1337	case 5 ... 7:
1338		return &unmap_pool[2];
1339	case 8:
1340		return &unmap_pool[3];
1341#endif
1342	default:
1343		BUG();
1344		return NULL;
1345	}
1346}
1347
1348static void dmaengine_unmap(struct kref *kref)
1349{
1350	struct dmaengine_unmap_data *unmap = container_of(kref, typeof(*unmap), kref);
1351	struct device *dev = unmap->dev;
1352	int cnt, i;
1353
1354	cnt = unmap->to_cnt;
1355	for (i = 0; i < cnt; i++)
1356		dma_unmap_page(dev, unmap->addr[i], unmap->len,
1357			       DMA_TO_DEVICE);
1358	cnt += unmap->from_cnt;
1359	for (; i < cnt; i++)
1360		dma_unmap_page(dev, unmap->addr[i], unmap->len,
1361			       DMA_FROM_DEVICE);
1362	cnt += unmap->bidi_cnt;
1363	for (; i < cnt; i++) {
1364		if (unmap->addr[i] == 0)
1365			continue;
1366		dma_unmap_page(dev, unmap->addr[i], unmap->len,
1367			       DMA_BIDIRECTIONAL);
1368	}
1369	cnt = unmap->map_cnt;
1370	mempool_free(unmap, __get_unmap_pool(cnt)->pool);
1371}
1372
1373void dmaengine_unmap_put(struct dmaengine_unmap_data *unmap)
1374{
1375	if (unmap)
1376		kref_put(&unmap->kref, dmaengine_unmap);
1377}
1378EXPORT_SYMBOL_GPL(dmaengine_unmap_put);
1379
1380static void dmaengine_destroy_unmap_pool(void)
1381{
1382	int i;
1383
1384	for (i = 0; i < ARRAY_SIZE(unmap_pool); i++) {
1385		struct dmaengine_unmap_pool *p = &unmap_pool[i];
1386
1387		mempool_destroy(p->pool);
1388		p->pool = NULL;
1389		kmem_cache_destroy(p->cache);
1390		p->cache = NULL;
1391	}
1392}
1393
1394static int __init dmaengine_init_unmap_pool(void)
1395{
1396	int i;
1397
1398	for (i = 0; i < ARRAY_SIZE(unmap_pool); i++) {
1399		struct dmaengine_unmap_pool *p = &unmap_pool[i];
1400		size_t size;
1401
1402		size = sizeof(struct dmaengine_unmap_data) +
1403		       sizeof(dma_addr_t) * p->size;
1404
1405		p->cache = kmem_cache_create(p->name, size, 0,
1406					     SLAB_HWCACHE_ALIGN, NULL);
1407		if (!p->cache)
1408			break;
1409		p->pool = mempool_create_slab_pool(1, p->cache);
1410		if (!p->pool)
1411			break;
1412	}
1413
1414	if (i == ARRAY_SIZE(unmap_pool))
1415		return 0;
1416
1417	dmaengine_destroy_unmap_pool();
1418	return -ENOMEM;
1419}
1420
1421struct dmaengine_unmap_data *
1422dmaengine_get_unmap_data(struct device *dev, int nr, gfp_t flags)
1423{
1424	struct dmaengine_unmap_data *unmap;
1425
1426	unmap = mempool_alloc(__get_unmap_pool(nr)->pool, flags);
1427	if (!unmap)
1428		return NULL;
1429
1430	memset(unmap, 0, sizeof(*unmap));
1431	kref_init(&unmap->kref);
1432	unmap->dev = dev;
1433	unmap->map_cnt = nr;
1434
1435	return unmap;
1436}
1437EXPORT_SYMBOL(dmaengine_get_unmap_data);
1438
1439void dma_async_tx_descriptor_init(struct dma_async_tx_descriptor *tx,
1440	struct dma_chan *chan)
1441{
1442	tx->chan = chan;
1443	#ifdef CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH
1444	spin_lock_init(&tx->lock);
1445	#endif
1446}
1447EXPORT_SYMBOL(dma_async_tx_descriptor_init);
1448
1449static inline int desc_check_and_set_metadata_mode(
1450	struct dma_async_tx_descriptor *desc, enum dma_desc_metadata_mode mode)
1451{
1452	/* Make sure that the metadata mode is not mixed */
1453	if (!desc->desc_metadata_mode) {
1454		if (dmaengine_is_metadata_mode_supported(desc->chan, mode))
1455			desc->desc_metadata_mode = mode;
1456		else
1457			return -ENOTSUPP;
1458	} else if (desc->desc_metadata_mode != mode) {
1459		return -EINVAL;
1460	}
1461
1462	return 0;
1463}
1464
1465int dmaengine_desc_attach_metadata(struct dma_async_tx_descriptor *desc,
1466				   void *data, size_t len)
1467{
1468	int ret;
1469
1470	if (!desc)
1471		return -EINVAL;
1472
1473	ret = desc_check_and_set_metadata_mode(desc, DESC_METADATA_CLIENT);
1474	if (ret)
1475		return ret;
1476
1477	if (!desc->metadata_ops || !desc->metadata_ops->attach)
1478		return -ENOTSUPP;
1479
1480	return desc->metadata_ops->attach(desc, data, len);
1481}
1482EXPORT_SYMBOL_GPL(dmaengine_desc_attach_metadata);
1483
1484void *dmaengine_desc_get_metadata_ptr(struct dma_async_tx_descriptor *desc,
1485				      size_t *payload_len, size_t *max_len)
1486{
1487	int ret;
1488
1489	if (!desc)
1490		return ERR_PTR(-EINVAL);
1491
1492	ret = desc_check_and_set_metadata_mode(desc, DESC_METADATA_ENGINE);
1493	if (ret)
1494		return ERR_PTR(ret);
1495
1496	if (!desc->metadata_ops || !desc->metadata_ops->get_ptr)
1497		return ERR_PTR(-ENOTSUPP);
1498
1499	return desc->metadata_ops->get_ptr(desc, payload_len, max_len);
1500}
1501EXPORT_SYMBOL_GPL(dmaengine_desc_get_metadata_ptr);
1502
1503int dmaengine_desc_set_metadata_len(struct dma_async_tx_descriptor *desc,
1504				    size_t payload_len)
1505{
1506	int ret;
1507
1508	if (!desc)
1509		return -EINVAL;
1510
1511	ret = desc_check_and_set_metadata_mode(desc, DESC_METADATA_ENGINE);
1512	if (ret)
1513		return ret;
1514
1515	if (!desc->metadata_ops || !desc->metadata_ops->set_len)
1516		return -ENOTSUPP;
1517
1518	return desc->metadata_ops->set_len(desc, payload_len);
1519}
1520EXPORT_SYMBOL_GPL(dmaengine_desc_set_metadata_len);
1521
1522/**
1523 * dma_wait_for_async_tx - spin wait for a transaction to complete
1524 * @tx:		in-flight transaction to wait on
1525 */
1526enum dma_status
1527dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx)
1528{
1529	unsigned long dma_sync_wait_timeout = jiffies + msecs_to_jiffies(5000);
1530
1531	if (!tx)
1532		return DMA_COMPLETE;
1533
1534	while (tx->cookie == -EBUSY) {
1535		if (time_after_eq(jiffies, dma_sync_wait_timeout)) {
1536			dev_err(tx->chan->device->dev,
1537				"%s timeout waiting for descriptor submission\n",
1538				__func__);
1539			return DMA_ERROR;
1540		}
1541		cpu_relax();
1542	}
1543	return dma_sync_wait(tx->chan, tx->cookie);
1544}
1545EXPORT_SYMBOL_GPL(dma_wait_for_async_tx);
1546
1547/**
1548 * dma_run_dependencies - process dependent operations on the target channel
1549 * @tx:		transaction with dependencies
1550 *
1551 * Helper routine for DMA drivers to process (start) dependent operations
1552 * on their target channel.
1553 */
1554void dma_run_dependencies(struct dma_async_tx_descriptor *tx)
1555{
1556	struct dma_async_tx_descriptor *dep = txd_next(tx);
1557	struct dma_async_tx_descriptor *dep_next;
1558	struct dma_chan *chan;
1559
1560	if (!dep)
1561		return;
1562
1563	/* we'll submit tx->next now, so clear the link */
1564	txd_clear_next(tx);
1565	chan = dep->chan;
1566
1567	/* keep submitting up until a channel switch is detected
1568	 * in that case we will be called again as a result of
1569	 * processing the interrupt from async_tx_channel_switch
1570	 */
1571	for (; dep; dep = dep_next) {
1572		txd_lock(dep);
1573		txd_clear_parent(dep);
1574		dep_next = txd_next(dep);
1575		if (dep_next && dep_next->chan == chan)
1576			txd_clear_next(dep); /* ->next will be submitted */
1577		else
1578			dep_next = NULL; /* submit current dep and terminate */
1579		txd_unlock(dep);
1580
1581		dep->tx_submit(dep);
1582	}
1583
1584	chan->device->device_issue_pending(chan);
1585}
1586EXPORT_SYMBOL_GPL(dma_run_dependencies);
1587
1588static int __init dma_bus_init(void)
1589{
1590	int err = dmaengine_init_unmap_pool();
1591
1592	if (err)
1593		return err;
1594
1595	err = class_register(&dma_devclass);
1596	if (!err)
1597		dmaengine_debugfs_init();
1598
1599	return err;
1600}
1601arch_initcall(dma_bus_init);