diff --git a/kern/drivers/dma/dmaengine.c b/kern/drivers/dma/dmaengine.c
new file mode 100644
index 0000000..3a11b10
--- /dev/null
+++ b/kern/drivers/dma/dmaengine.c
@@ -0,0 +1,1383 @@
+/*
+ * Copyright(c) 2004 - 2006 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * The full GNU General Public License is included in this distribution in the
+ * file called COPYING.
+ */
+
+/*
+ * This code implements the DMA subsystem. It provides a HW-neutral interface
+ * for other kernel code to use asynchronous memory copy capabilities,
+ * if present, and allows different HW DMA drivers to register as providing
+ * this capability.
+ *
+ * Due to the fact we are accelerating what is already a relatively fast
+ * operation, the code goes to great lengths to avoid additional overhead,
+ * such as locking.
+ *
+ * LOCKING:
+ *
+ * The subsystem keeps a global list of dma_device structs it is protected by a
+ * mutex, dma_list_mutex.
+ *
+ * A subsystem can get access to a channel by calling dmaengine_get() followed
+ * by dma_find_channel(), or if it has need for an exclusive channel it can call
+ * dma_request_channel().  Once a channel is allocated a reference is taken
+ * against its corresponding driver to disable removal.
+ *
+ * Each device has a channels list, which runs unlocked but is never modified
+ * once the device is registered, it's just setup by the driver.
+ *
+ * See Documentation/driver-api/dmaengine for more details
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/platform_device.h>
+#include <linux/dma-mapping.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/device.h>
+#include <linux/dmaengine.h>
+#include <linux/hardirq.h>
+#include <linux/spinlock.h>
+#include <linux/percpu.h>
+#include <linux/rcupdate.h>
+#include <linux/mutex.h>
+#include <linux/jiffies.h>
+#include <linux/rculist.h>
+#include <linux/idr.h>
+#include <linux/slab.h>
+#include <linux/acpi.h>
+#include <linux/acpi_dma.h>
+#include <linux/of_dma.h>
+#include <linux/mempool.h>
+#include <linux/numa.h>
+
+static DEFINE_MUTEX(dma_list_mutex);
+static DEFINE_IDA(dma_ida);
+static LIST_HEAD(dma_device_list);
+static long dmaengine_ref_count;
+
+/* --- sysfs implementation --- */
+
+/**
+ * dev_to_dma_chan - convert a device pointer to the its sysfs container object
+ * @dev - device node
+ *
+ * Must be called under dma_list_mutex
+ */
+static struct dma_chan *dev_to_dma_chan(struct device *dev)
+{
+	struct dma_chan_dev *chan_dev;
+
+	chan_dev = container_of(dev, typeof(*chan_dev), device);
+	return chan_dev->chan;
+}
+
+static ssize_t memcpy_count_show(struct device *dev,
+				 struct device_attribute *attr, char *buf)
+{
+	struct dma_chan *chan;
+	unsigned long count = 0;
+	int i;
+	int err;
+
+	mutex_lock(&dma_list_mutex);
+	chan = dev_to_dma_chan(dev);
+	if (chan) {
+		for_each_possible_cpu(i)
+			count += per_cpu_ptr(chan->local, i)->memcpy_count;
+		err = sprintf(buf, "%lu\n", count);
+	} else
+		err = -ENODEV;
+	mutex_unlock(&dma_list_mutex);
+
+	return err;
+}
+static DEVICE_ATTR_RO(memcpy_count);
+
+static ssize_t bytes_transferred_show(struct device *dev,
+				      struct device_attribute *attr, char *buf)
+{
+	struct dma_chan *chan;
+	unsigned long count = 0;
+	int i;
+	int err;
+
+	mutex_lock(&dma_list_mutex);
+	chan = dev_to_dma_chan(dev);
+	if (chan) {
+		for_each_possible_cpu(i)
+			count += per_cpu_ptr(chan->local, i)->bytes_transferred;
+		err = sprintf(buf, "%lu\n", count);
+	} else
+		err = -ENODEV;
+	mutex_unlock(&dma_list_mutex);
+
+	return err;
+}
+static DEVICE_ATTR_RO(bytes_transferred);
+
+static ssize_t in_use_show(struct device *dev, struct device_attribute *attr,
+			   char *buf)
+{
+	struct dma_chan *chan;
+	int err;
+
+	mutex_lock(&dma_list_mutex);
+	chan = dev_to_dma_chan(dev);
+	if (chan)
+		err = sprintf(buf, "%d\n", chan->client_count);
+	else
+		err = -ENODEV;
+	mutex_unlock(&dma_list_mutex);
+
+	return err;
+}
+static DEVICE_ATTR_RO(in_use);
+
+static struct attribute *dma_dev_attrs[] = {
+	&dev_attr_memcpy_count.attr,
+	&dev_attr_bytes_transferred.attr,
+	&dev_attr_in_use.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(dma_dev);
+
+static void chan_dev_release(struct device *dev)
+{
+	struct dma_chan_dev *chan_dev;
+
+	chan_dev = container_of(dev, typeof(*chan_dev), device);
+	if (atomic_dec_and_test(chan_dev->idr_ref)) {
+		ida_free(&dma_ida, chan_dev->dev_id);
+		kfree(chan_dev->idr_ref);
+	}
+	kfree(chan_dev);
+}
+
+static struct class dma_devclass = {
+	.name		= "dma",
+	.dev_groups	= dma_dev_groups,
+	.dev_release	= chan_dev_release,
+};
+
+/* --- client and device registration --- */
+
+#define dma_device_satisfies_mask(device, mask) \
+	__dma_device_satisfies_mask((device), &(mask))
+static int
+__dma_device_satisfies_mask(struct dma_device *device,
+			    const dma_cap_mask_t *want)
+{
+	dma_cap_mask_t has;
+
+	bitmap_and(has.bits, want->bits, device->cap_mask.bits,
+		DMA_TX_TYPE_END);
+	return bitmap_equal(want->bits, has.bits, DMA_TX_TYPE_END);
+}
+
+static struct module *dma_chan_to_owner(struct dma_chan *chan)
+{
+	return chan->device->dev->driver->owner;
+}
+
+/**
+ * balance_ref_count - catch up the channel reference count
+ * @chan - channel to balance ->client_count versus dmaengine_ref_count
+ *
+ * balance_ref_count must be called under dma_list_mutex
+ */
+static void balance_ref_count(struct dma_chan *chan)
+{
+	struct module *owner = dma_chan_to_owner(chan);
+
+	while (chan->client_count < dmaengine_ref_count) {
+		__module_get(owner);
+		chan->client_count++;
+	}
+}
+
+/**
+ * dma_chan_get - try to grab a dma channel's parent driver module
+ * @chan - channel to grab
+ *
+ * Must be called under dma_list_mutex
+ */
+static int dma_chan_get(struct dma_chan *chan)
+{
+	struct module *owner = dma_chan_to_owner(chan);
+	int ret;
+
+	/* The channel is already in use, update client count */
+	if (chan->client_count) {
+		__module_get(owner);
+		goto out;
+	}
+
+	if (!try_module_get(owner))
+		return -ENODEV;
+
+	/* allocate upon first client reference */
+	if (chan->device->device_alloc_chan_resources) {
+		ret = chan->device->device_alloc_chan_resources(chan);
+		if (ret < 0)
+			goto err_out;
+	}
+
+	if (!dma_has_cap(DMA_PRIVATE, chan->device->cap_mask))
+		balance_ref_count(chan);
+
+out:
+	chan->client_count++;
+	return 0;
+
+err_out:
+	module_put(owner);
+	return ret;
+}
+
+/**
+ * dma_chan_put - drop a reference to a dma channel's parent driver module
+ * @chan - channel to release
+ *
+ * Must be called under dma_list_mutex
+ */
+static void dma_chan_put(struct dma_chan *chan)
+{
+	/* This channel is not in use, bail out */
+	if (!chan->client_count)
+		return;
+
+	chan->client_count--;
+	module_put(dma_chan_to_owner(chan));
+
+	/* This channel is not in use anymore, free it */
+	if (!chan->client_count && chan->device->device_free_chan_resources) {
+		/* Make sure all operations have completed */
+		dmaengine_synchronize(chan);
+		chan->device->device_free_chan_resources(chan);
+	}
+
+	/* If the channel is used via a DMA request router, free the mapping */
+	if (chan->router && chan->router->route_free) {
+		chan->router->route_free(chan->router->dev, chan->route_data);
+		chan->router = NULL;
+		chan->route_data = NULL;
+	}
+}
+
+enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie)
+{
+	enum dma_status status;
+	unsigned long dma_sync_wait_timeout = jiffies + msecs_to_jiffies(5000);
+
+	dma_async_issue_pending(chan);
+	do {
+		status = dma_async_is_tx_complete(chan, cookie, NULL, NULL);
+		if (time_after_eq(jiffies, dma_sync_wait_timeout)) {
+			dev_err(chan->device->dev, "%s: timeout!\n", __func__);
+			return DMA_ERROR;
+		}
+		if (status != DMA_IN_PROGRESS)
+			break;
+		cpu_relax();
+	} while (1);
+
+	return status;
+}
+EXPORT_SYMBOL(dma_sync_wait);
+
+/**
+ * dma_cap_mask_all - enable iteration over all operation types
+ */
+static dma_cap_mask_t dma_cap_mask_all;
+
+/**
+ * dma_chan_tbl_ent - tracks channel allocations per core/operation
+ * @chan - associated channel for this entry
+ */
+struct dma_chan_tbl_ent {
+	struct dma_chan *chan;
+};
+
+/**
+ * channel_table - percpu lookup table for memory-to-memory offload providers
+ */
+static struct dma_chan_tbl_ent __percpu *channel_table[DMA_TX_TYPE_END];
+
+static int __init dma_channel_table_init(void)
+{
+	enum dma_transaction_type cap;
+	int err = 0;
+
+	bitmap_fill(dma_cap_mask_all.bits, DMA_TX_TYPE_END);
+
+	/* 'interrupt', 'private', and 'slave' are channel capabilities,
+	 * but are not associated with an operation so they do not need
+	 * an entry in the channel_table
+	 */
+	clear_bit(DMA_INTERRUPT, dma_cap_mask_all.bits);
+	clear_bit(DMA_PRIVATE, dma_cap_mask_all.bits);
+	clear_bit(DMA_SLAVE, dma_cap_mask_all.bits);
+
+	for_each_dma_cap_mask(cap, dma_cap_mask_all) {
+		channel_table[cap] = alloc_percpu(struct dma_chan_tbl_ent);
+		if (!channel_table[cap]) {
+			err = -ENOMEM;
+			break;
+		}
+	}
+
+	if (err) {
+		pr_err("initialization failure\n");
+		for_each_dma_cap_mask(cap, dma_cap_mask_all)
+			free_percpu(channel_table[cap]);
+	}
+
+	return err;
+}
+arch_initcall(dma_channel_table_init);
+
+/**
+ * dma_find_channel - find a channel to carry out the operation
+ * @tx_type: transaction type
+ */
+struct dma_chan *dma_find_channel(enum dma_transaction_type tx_type)
+{
+	return this_cpu_read(channel_table[tx_type]->chan);
+}
+EXPORT_SYMBOL(dma_find_channel);
+
+/**
+ * dma_issue_pending_all - flush all pending operations across all channels
+ */
+void dma_issue_pending_all(void)
+{
+	struct dma_device *device;
+	struct dma_chan *chan;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(device, &dma_device_list, global_node) {
+		if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
+			continue;
+		list_for_each_entry(chan, &device->channels, device_node)
+			if (chan->client_count)
+				device->device_issue_pending(chan);
+	}
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL(dma_issue_pending_all);
+
+/**
+ * dma_chan_is_local - returns true if the channel is in the same numa-node as the cpu
+ */
+static bool dma_chan_is_local(struct dma_chan *chan, int cpu)
+{
+	int node = dev_to_node(chan->device->dev);
+	return node == NUMA_NO_NODE ||
+		cpumask_test_cpu(cpu, cpumask_of_node(node));
+}
+
+/**
+ * min_chan - returns the channel with min count and in the same numa-node as the cpu
+ * @cap: capability to match
+ * @cpu: cpu index which the channel should be close to
+ *
+ * If some channels are close to the given cpu, the one with the lowest
+ * reference count is returned. Otherwise, cpu is ignored and only the
+ * reference count is taken into account.
+ * Must be called under dma_list_mutex.
+ */
+static struct dma_chan *min_chan(enum dma_transaction_type cap, int cpu)
+{
+	struct dma_device *device;
+	struct dma_chan *chan;
+	struct dma_chan *min = NULL;
+	struct dma_chan *localmin = NULL;
+
+	list_for_each_entry(device, &dma_device_list, global_node) {
+		if (!dma_has_cap(cap, device->cap_mask) ||
+		    dma_has_cap(DMA_PRIVATE, device->cap_mask))
+			continue;
+		list_for_each_entry(chan, &device->channels, device_node) {
+			if (!chan->client_count)
+				continue;
+			if (!min || chan->table_count < min->table_count)
+				min = chan;
+
+			if (dma_chan_is_local(chan, cpu))
+				if (!localmin ||
+				    chan->table_count < localmin->table_count)
+					localmin = chan;
+		}
+	}
+
+	chan = localmin ? localmin : min;
+
+	if (chan)
+		chan->table_count++;
+
+	return chan;
+}
+
+/**
+ * dma_channel_rebalance - redistribute the available channels
+ *
+ * Optimize for cpu isolation (each cpu gets a dedicated channel for an
+ * operation type) in the SMP case,  and operation isolation (avoid
+ * multi-tasking channels) in the non-SMP case.  Must be called under
+ * dma_list_mutex.
+ */
+static void dma_channel_rebalance(void)
+{
+	struct dma_chan *chan;
+	struct dma_device *device;
+	int cpu;
+	int cap;
+
+	/* undo the last distribution */
+	for_each_dma_cap_mask(cap, dma_cap_mask_all)
+		for_each_possible_cpu(cpu)
+			per_cpu_ptr(channel_table[cap], cpu)->chan = NULL;
+
+	list_for_each_entry(device, &dma_device_list, global_node) {
+		if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
+			continue;
+		list_for_each_entry(chan, &device->channels, device_node)
+			chan->table_count = 0;
+	}
+
+	/* don't populate the channel_table if no clients are available */
+	if (!dmaengine_ref_count)
+		return;
+
+	/* redistribute available channels */
+	for_each_dma_cap_mask(cap, dma_cap_mask_all)
+		for_each_online_cpu(cpu) {
+			chan = min_chan(cap, cpu);
+			per_cpu_ptr(channel_table[cap], cpu)->chan = chan;
+		}
+}
+
+int dma_get_slave_caps(struct dma_chan *chan, struct dma_slave_caps *caps)
+{
+	struct dma_device *device;
+
+	if (!chan || !caps)
+		return -EINVAL;
+
+	device = chan->device;
+
+	/* check if the channel supports slave transactions */
+	if (!(test_bit(DMA_SLAVE, device->cap_mask.bits) ||
+	      test_bit(DMA_CYCLIC, device->cap_mask.bits)))
+		return -ENXIO;
+
+	/*
+	 * Check whether it reports it uses the generic slave
+	 * capabilities, if not, that means it doesn't support any
+	 * kind of slave capabilities reporting.
+	 */
+	if (!device->directions)
+		return -ENXIO;
+
+	caps->src_addr_widths = device->src_addr_widths;
+	caps->dst_addr_widths = device->dst_addr_widths;
+	caps->directions = device->directions;
+	caps->max_burst = device->max_burst;
+	caps->residue_granularity = device->residue_granularity;
+	caps->descriptor_reuse = device->descriptor_reuse;
+	caps->cmd_pause = !!device->device_pause;
+	caps->cmd_resume = !!device->device_resume;
+	caps->cmd_terminate = !!device->device_terminate_all;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dma_get_slave_caps);
+
+static struct dma_chan *private_candidate(const dma_cap_mask_t *mask,
+					  struct dma_device *dev,
+					  dma_filter_fn fn, void *fn_param)
+{
+	struct dma_chan *chan;
+
+	if (mask && !__dma_device_satisfies_mask(dev, mask)) {
+		dev_dbg(dev->dev, "%s: wrong capabilities\n", __func__);
+		return NULL;
+	}
+	/* devices with multiple channels need special handling as we need to
+	 * ensure that all channels are either private or public.
+	 */
+	if (dev->chancnt > 1 && !dma_has_cap(DMA_PRIVATE, dev->cap_mask))
+		list_for_each_entry(chan, &dev->channels, device_node) {
+			/* some channels are already publicly allocated */
+			if (chan->client_count)
+				return NULL;
+		}
+
+	list_for_each_entry(chan, &dev->channels, device_node) {
+		if (chan->client_count) {
+			dev_dbg(dev->dev, "%s: %s busy\n",
+				 __func__, dma_chan_name(chan));
+			continue;
+		}
+		if (fn && !fn(chan, fn_param)) {
+			dev_dbg(dev->dev, "%s: %s filter said false\n",
+				 __func__, dma_chan_name(chan));
+			continue;
+		}
+		return chan;
+	}
+
+	return NULL;
+}
+
+static struct dma_chan *find_candidate(struct dma_device *device,
+				       const dma_cap_mask_t *mask,
+				       dma_filter_fn fn, void *fn_param)
+{
+	struct dma_chan *chan = private_candidate(mask, device, fn, fn_param);
+	int err;
+
+	if (chan) {
+		/* Found a suitable channel, try to grab, prep, and return it.
+		 * We first set DMA_PRIVATE to disable balance_ref_count as this
+		 * channel will not be published in the general-purpose
+		 * allocator
+		 */
+		dma_cap_set(DMA_PRIVATE, device->cap_mask);
+		device->privatecnt++;
+		err = dma_chan_get(chan);
+
+		if (err) {
+			if (err == -ENODEV) {
+				dev_dbg(device->dev, "%s: %s module removed\n",
+					__func__, dma_chan_name(chan));
+				list_del_rcu(&device->global_node);
+			} else
+				dev_dbg(device->dev,
+					"%s: failed to get %s: (%d)\n",
+					 __func__, dma_chan_name(chan), err);
+
+			if (--device->privatecnt == 0)
+				dma_cap_clear(DMA_PRIVATE, device->cap_mask);
+
+			chan = ERR_PTR(err);
+		}
+	}
+
+	return chan ? chan : ERR_PTR(-EPROBE_DEFER);
+}
+
+/**
+ * dma_get_slave_channel - try to get specific channel exclusively
+ * @chan: target channel
+ */
+struct dma_chan *dma_get_slave_channel(struct dma_chan *chan)
+{
+	int err = -EBUSY;
+
+	/* lock against __dma_request_channel */
+	mutex_lock(&dma_list_mutex);
+
+	if (chan->client_count == 0) {
+		struct dma_device *device = chan->device;
+
+		dma_cap_set(DMA_PRIVATE, device->cap_mask);
+		device->privatecnt++;
+		err = dma_chan_get(chan);
+		if (err) {
+			dev_dbg(chan->device->dev,
+				"%s: failed to get %s: (%d)\n",
+				__func__, dma_chan_name(chan), err);
+			chan = NULL;
+			if (--device->privatecnt == 0)
+				dma_cap_clear(DMA_PRIVATE, device->cap_mask);
+		}
+	} else
+		chan = NULL;
+
+	mutex_unlock(&dma_list_mutex);
+
+
+	return chan;
+}
+EXPORT_SYMBOL_GPL(dma_get_slave_channel);
+
+struct dma_chan *dma_get_any_slave_channel(struct dma_device *device)
+{
+	dma_cap_mask_t mask;
+	struct dma_chan *chan;
+
+	dma_cap_zero(mask);
+	dma_cap_set(DMA_SLAVE, mask);
+
+	/* lock against __dma_request_channel */
+	mutex_lock(&dma_list_mutex);
+
+	chan = find_candidate(device, &mask, NULL, NULL);
+
+	mutex_unlock(&dma_list_mutex);
+
+	return IS_ERR(chan) ? NULL : chan;
+}
+EXPORT_SYMBOL_GPL(dma_get_any_slave_channel);
+
+/**
+ * __dma_request_channel - try to allocate an exclusive channel
+ * @mask: capabilities that the channel must satisfy
+ * @fn: optional callback to disposition available channels
+ * @fn_param: opaque parameter to pass to dma_filter_fn
+ *
+ * Returns pointer to appropriate DMA channel on success or NULL.
+ */
+struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
+				       dma_filter_fn fn, void *fn_param)
+{
+	struct dma_device *device, *_d;
+	struct dma_chan *chan = NULL;
+
+	/* Find a channel */
+	mutex_lock(&dma_list_mutex);
+	list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
+		chan = find_candidate(device, mask, fn, fn_param);
+		if (!IS_ERR(chan))
+			break;
+
+		chan = NULL;
+	}
+	mutex_unlock(&dma_list_mutex);
+
+	pr_debug("%s: %s (%s)\n",
+		 __func__,
+		 chan ? "success" : "fail",
+		 chan ? dma_chan_name(chan) : NULL);
+
+	return chan;
+}
+EXPORT_SYMBOL_GPL(__dma_request_channel);
+
+static const struct dma_slave_map *dma_filter_match(struct dma_device *device,
+						    const char *name,
+						    struct device *dev)
+{
+	int i;
+
+	if (!device->filter.mapcnt)
+		return NULL;
+
+	for (i = 0; i < device->filter.mapcnt; i++) {
+		const struct dma_slave_map *map = &device->filter.map[i];
+
+		if (!strcmp(map->devname, dev_name(dev)) &&
+		    !strcmp(map->slave, name))
+			return map;
+	}
+
+	return NULL;
+}
+
+/**
+ * dma_request_chan - try to allocate an exclusive slave channel
+ * @dev:	pointer to client device structure
+ * @name:	slave channel name
+ *
+ * Returns pointer to appropriate DMA channel on success or an error pointer.
+ */
+struct dma_chan *dma_request_chan(struct device *dev, const char *name)
+{
+	struct dma_device *d, *_d;
+	struct dma_chan *chan = NULL;
+
+	/* If device-tree is present get slave info from here */
+	if (dev->of_node)
+		chan = of_dma_request_slave_channel(dev->of_node, name);
+
+	/* If device was enumerated by ACPI get slave info from here */
+	if (has_acpi_companion(dev) && !chan)
+		chan = acpi_dma_request_slave_chan_by_name(dev, name);
+
+	if (chan) {
+		/* Valid channel found or requester need to be deferred */
+		if (!IS_ERR(chan) || PTR_ERR(chan) == -EPROBE_DEFER)
+			return chan;
+	}
+
+	/* Try to find the channel via the DMA filter map(s) */
+	mutex_lock(&dma_list_mutex);
+	list_for_each_entry_safe(d, _d, &dma_device_list, global_node) {
+		dma_cap_mask_t mask;
+		const struct dma_slave_map *map = dma_filter_match(d, name, dev);
+
+		if (!map)
+			continue;
+
+		dma_cap_zero(mask);
+		dma_cap_set(DMA_SLAVE, mask);
+
+		chan = find_candidate(d, &mask, d->filter.fn, map->param);
+		if (!IS_ERR(chan))
+			break;
+	}
+	mutex_unlock(&dma_list_mutex);
+
+	return chan ? chan : ERR_PTR(-EPROBE_DEFER);
+}
+EXPORT_SYMBOL_GPL(dma_request_chan);
+
+/**
+ * dma_request_slave_channel - try to allocate an exclusive slave channel
+ * @dev:	pointer to client device structure
+ * @name:	slave channel name
+ *
+ * Returns pointer to appropriate DMA channel on success or NULL.
+ */
+struct dma_chan *dma_request_slave_channel(struct device *dev,
+					   const char *name)
+{
+	struct dma_chan *ch = dma_request_chan(dev, name);
+	if (IS_ERR(ch))
+		return NULL;
+
+	return ch;
+}
+EXPORT_SYMBOL_GPL(dma_request_slave_channel);
+
+/**
+ * dma_request_chan_by_mask - allocate a channel satisfying certain capabilities
+ * @mask: capabilities that the channel must satisfy
+ *
+ * Returns pointer to appropriate DMA channel on success or an error pointer.
+ */
+struct dma_chan *dma_request_chan_by_mask(const dma_cap_mask_t *mask)
+{
+	struct dma_chan *chan;
+
+	if (!mask)
+		return ERR_PTR(-ENODEV);
+
+	chan = __dma_request_channel(mask, NULL, NULL);
+	if (!chan) {
+		mutex_lock(&dma_list_mutex);
+		if (list_empty(&dma_device_list))
+			chan = ERR_PTR(-EPROBE_DEFER);
+		else
+			chan = ERR_PTR(-ENODEV);
+		mutex_unlock(&dma_list_mutex);
+	}
+
+	return chan;
+}
+EXPORT_SYMBOL_GPL(dma_request_chan_by_mask);
+
+void dma_release_channel(struct dma_chan *chan)
+{
+	mutex_lock(&dma_list_mutex);
+	WARN_ONCE(chan->client_count != 1,
+		  "chan reference count %d != 1\n", chan->client_count);
+	dma_chan_put(chan);
+	/* drop PRIVATE cap enabled by __dma_request_channel() */
+	if (--chan->device->privatecnt == 0)
+		dma_cap_clear(DMA_PRIVATE, chan->device->cap_mask);
+	mutex_unlock(&dma_list_mutex);
+}
+EXPORT_SYMBOL_GPL(dma_release_channel);
+
+/**
+ * dmaengine_get - register interest in dma_channels
+ */
+void dmaengine_get(void)
+{
+	struct dma_device *device, *_d;
+	struct dma_chan *chan;
+	int err;
+
+	mutex_lock(&dma_list_mutex);
+	dmaengine_ref_count++;
+
+	/* try to grab channels */
+	list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
+		if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
+			continue;
+		list_for_each_entry(chan, &device->channels, device_node) {
+			err = dma_chan_get(chan);
+			if (err == -ENODEV) {
+				/* module removed before we could use it */
+				list_del_rcu(&device->global_node);
+				break;
+			} else if (err)
+				dev_dbg(chan->device->dev,
+					"%s: failed to get %s: (%d)\n",
+					__func__, dma_chan_name(chan), err);
+		}
+	}
+
+	/* if this is the first reference and there were channels
+	 * waiting we need to rebalance to get those channels
+	 * incorporated into the channel table
+	 */
+	if (dmaengine_ref_count == 1)
+		dma_channel_rebalance();
+	mutex_unlock(&dma_list_mutex);
+}
+EXPORT_SYMBOL(dmaengine_get);
+
+/**
+ * dmaengine_put - let dma drivers be removed when ref_count == 0
+ */
+void dmaengine_put(void)
+{
+	struct dma_device *device;
+	struct dma_chan *chan;
+
+	mutex_lock(&dma_list_mutex);
+	dmaengine_ref_count--;
+	BUG_ON(dmaengine_ref_count < 0);
+	/* drop channel references */
+	list_for_each_entry(device, &dma_device_list, global_node) {
+		if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
+			continue;
+		list_for_each_entry(chan, &device->channels, device_node)
+			dma_chan_put(chan);
+	}
+	mutex_unlock(&dma_list_mutex);
+}
+EXPORT_SYMBOL(dmaengine_put);
+
+static bool device_has_all_tx_types(struct dma_device *device)
+{
+	/* A device that satisfies this test has channels that will never cause
+	 * an async_tx channel switch event as all possible operation types can
+	 * be handled.
+	 */
+	#ifdef CONFIG_ASYNC_TX_DMA
+	if (!dma_has_cap(DMA_INTERRUPT, device->cap_mask))
+		return false;
+	#endif
+
+	#if IS_ENABLED(CONFIG_ASYNC_MEMCPY)
+	if (!dma_has_cap(DMA_MEMCPY, device->cap_mask))
+		return false;
+	#endif
+
+	#if IS_ENABLED(CONFIG_ASYNC_XOR)
+	if (!dma_has_cap(DMA_XOR, device->cap_mask))
+		return false;
+
+	#ifndef CONFIG_ASYNC_TX_DISABLE_XOR_VAL_DMA
+	if (!dma_has_cap(DMA_XOR_VAL, device->cap_mask))
+		return false;
+	#endif
+	#endif
+
+	#if IS_ENABLED(CONFIG_ASYNC_PQ)
+	if (!dma_has_cap(DMA_PQ, device->cap_mask))
+		return false;
+
+	#ifndef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA
+	if (!dma_has_cap(DMA_PQ_VAL, device->cap_mask))
+		return false;
+	#endif
+	#endif
+
+	return true;
+}
+
+static int get_dma_id(struct dma_device *device)
+{
+	int rc = ida_alloc(&dma_ida, GFP_KERNEL);
+
+	if (rc < 0)
+		return rc;
+	device->dev_id = rc;
+	return 0;
+}
+
+/**
+ * dma_async_device_register - registers DMA devices found
+ * @device: &dma_device
+ */
+int dma_async_device_register(struct dma_device *device)
+{
+	int chancnt = 0, rc;
+	struct dma_chan* chan;
+	atomic_t *idr_ref;
+
+	if (!device)
+		return -ENODEV;
+
+	/* validate device routines */
+	if (!device->dev) {
+		pr_err("DMAdevice must have dev\n");
+		return -EIO;
+	}
+
+	if (dma_has_cap(DMA_MEMCPY, device->cap_mask) && !device->device_prep_dma_memcpy) {
+		dev_err(device->dev,
+			"Device claims capability %s, but op is not defined\n",
+			"DMA_MEMCPY");
+		return -EIO;
+	}
+
+	if (dma_has_cap(DMA_XOR, device->cap_mask) && !device->device_prep_dma_xor) {
+		dev_err(device->dev,
+			"Device claims capability %s, but op is not defined\n",
+			"DMA_XOR");
+		return -EIO;
+	}
+
+	if (dma_has_cap(DMA_XOR_VAL, device->cap_mask) && !device->device_prep_dma_xor_val) {
+		dev_err(device->dev,
+			"Device claims capability %s, but op is not defined\n",
+			"DMA_XOR_VAL");
+		return -EIO;
+	}
+
+	if (dma_has_cap(DMA_PQ, device->cap_mask) && !device->device_prep_dma_pq) {
+		dev_err(device->dev,
+			"Device claims capability %s, but op is not defined\n",
+			"DMA_PQ");
+		return -EIO;
+	}
+
+	if (dma_has_cap(DMA_PQ_VAL, device->cap_mask) && !device->device_prep_dma_pq_val) {
+		dev_err(device->dev,
+			"Device claims capability %s, but op is not defined\n",
+			"DMA_PQ_VAL");
+		return -EIO;
+	}
+
+	if (dma_has_cap(DMA_MEMSET, device->cap_mask) && !device->device_prep_dma_memset) {
+		dev_err(device->dev,
+			"Device claims capability %s, but op is not defined\n",
+			"DMA_MEMSET");
+		return -EIO;
+	}
+
+	if (dma_has_cap(DMA_INTERRUPT, device->cap_mask) && !device->device_prep_dma_interrupt) {
+		dev_err(device->dev,
+			"Device claims capability %s, but op is not defined\n",
+			"DMA_INTERRUPT");
+		return -EIO;
+	}
+
+	if (dma_has_cap(DMA_CYCLIC, device->cap_mask) && !device->device_prep_dma_cyclic) {
+		dev_err(device->dev,
+			"Device claims capability %s, but op is not defined\n",
+			"DMA_CYCLIC");
+		return -EIO;
+	}
+
+	if (dma_has_cap(DMA_INTERLEAVE, device->cap_mask) && !device->device_prep_interleaved_dma) {
+		dev_err(device->dev,
+			"Device claims capability %s, but op is not defined\n",
+			"DMA_INTERLEAVE");
+		return -EIO;
+	}
+
+
+	if (!device->device_tx_status) {
+		dev_err(device->dev, "Device tx_status is not defined\n");
+		return -EIO;
+	}
+
+
+	if (!device->device_issue_pending) {
+		dev_err(device->dev, "Device issue_pending is not defined\n");
+		return -EIO;
+	}
+
+	/* note: this only matters in the
+	 * CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH=n case
+	 */
+	if (device_has_all_tx_types(device))
+		dma_cap_set(DMA_ASYNC_TX, device->cap_mask);
+
+	idr_ref = kmalloc(sizeof(*idr_ref), GFP_KERNEL);
+	if (!idr_ref)
+		return -ENOMEM;
+	rc = get_dma_id(device);
+	if (rc != 0) {
+		kfree(idr_ref);
+		return rc;
+	}
+
+	atomic_set(idr_ref, 0);
+
+	/* represent channels in sysfs. Probably want devs too */
+	list_for_each_entry(chan, &device->channels, device_node) {
+		rc = -ENOMEM;
+		chan->local = alloc_percpu(typeof(*chan->local));
+		if (chan->local == NULL)
+			goto err_out;
+		chan->dev = kzalloc(sizeof(*chan->dev), GFP_KERNEL);
+		if (chan->dev == NULL) {
+			free_percpu(chan->local);
+			chan->local = NULL;
+			goto err_out;
+		}
+
+		chan->chan_id = chancnt++;
+		chan->dev->device.class = &dma_devclass;
+		chan->dev->device.parent = device->dev;
+		chan->dev->chan = chan;
+		chan->dev->idr_ref = idr_ref;
+		chan->dev->dev_id = device->dev_id;
+		atomic_inc(idr_ref);
+		dev_set_name(&chan->dev->device, "dma%dchan%d",
+			     device->dev_id, chan->chan_id);
+
+		rc = device_register(&chan->dev->device);
+		if (rc) {
+			free_percpu(chan->local);
+			chan->local = NULL;
+			kfree(chan->dev);
+			atomic_dec(idr_ref);
+			goto err_out;
+		}
+		chan->client_count = 0;
+	}
+
+	if (!chancnt) {
+		dev_err(device->dev, "%s: device has no channels!\n", __func__);
+		rc = -ENODEV;
+		goto err_out;
+	}
+
+	device->chancnt = chancnt;
+
+	mutex_lock(&dma_list_mutex);
+	/* take references on public channels */
+	if (dmaengine_ref_count && !dma_has_cap(DMA_PRIVATE, device->cap_mask))
+		list_for_each_entry(chan, &device->channels, device_node) {
+			/* if clients are already waiting for channels we need
+			 * to take references on their behalf
+			 */
+			if (dma_chan_get(chan) == -ENODEV) {
+				/* note we can only get here for the first
+				 * channel as the remaining channels are
+				 * guaranteed to get a reference
+				 */
+				rc = -ENODEV;
+				mutex_unlock(&dma_list_mutex);
+				goto err_out;
+			}
+		}
+	list_add_tail_rcu(&device->global_node, &dma_device_list);
+	if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
+		device->privatecnt++;	/* Always private */
+	dma_channel_rebalance();
+	mutex_unlock(&dma_list_mutex);
+
+	return 0;
+
+err_out:
+	/* if we never registered a channel just release the idr */
+	if (atomic_read(idr_ref) == 0) {
+		ida_free(&dma_ida, device->dev_id);
+		kfree(idr_ref);
+		return rc;
+	}
+
+	list_for_each_entry(chan, &device->channels, device_node) {
+		if (chan->local == NULL)
+			continue;
+		mutex_lock(&dma_list_mutex);
+		chan->dev->chan = NULL;
+		mutex_unlock(&dma_list_mutex);
+		device_unregister(&chan->dev->device);
+		free_percpu(chan->local);
+	}
+	return rc;
+}
+EXPORT_SYMBOL(dma_async_device_register);
+
+/**
+ * dma_async_device_unregister - unregister a DMA device
+ * @device: &dma_device
+ *
+ * This routine is called by dma driver exit routines, dmaengine holds module
+ * references to prevent it being called while channels are in use.
+ */
+void dma_async_device_unregister(struct dma_device *device)
+{
+	struct dma_chan *chan;
+
+	mutex_lock(&dma_list_mutex);
+	list_del_rcu(&device->global_node);
+	dma_channel_rebalance();
+	mutex_unlock(&dma_list_mutex);
+
+	list_for_each_entry(chan, &device->channels, device_node) {
+		WARN_ONCE(chan->client_count,
+			  "%s called while %d clients hold a reference\n",
+			  __func__, chan->client_count);
+		mutex_lock(&dma_list_mutex);
+		chan->dev->chan = NULL;
+		mutex_unlock(&dma_list_mutex);
+		device_unregister(&chan->dev->device);
+		free_percpu(chan->local);
+	}
+}
+EXPORT_SYMBOL(dma_async_device_unregister);
+
+static void dmam_device_release(struct device *dev, void *res)
+{
+	struct dma_device *device;
+
+	device = *(struct dma_device **)res;
+	dma_async_device_unregister(device);
+}
+
+/**
+ * dmaenginem_async_device_register - registers DMA devices found
+ * @device: &dma_device
+ *
+ * The operation is managed and will be undone on driver detach.
+ */
+int dmaenginem_async_device_register(struct dma_device *device)
+{
+	void *p;
+	int ret;
+
+	p = devres_alloc(dmam_device_release, sizeof(void *), GFP_KERNEL);
+	if (!p)
+		return -ENOMEM;
+
+	ret = dma_async_device_register(device);
+	if (!ret) {
+		*(struct dma_device **)p = device;
+		devres_add(device->dev, p);
+	} else {
+		devres_free(p);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(dmaenginem_async_device_register);
+
+struct dmaengine_unmap_pool {
+	struct kmem_cache *cache;
+	const char *name;
+	mempool_t *pool;
+	size_t size;
+};
+
+#define __UNMAP_POOL(x) { .size = x, .name = "dmaengine-unmap-" __stringify(x) }
+static struct dmaengine_unmap_pool unmap_pool[] = {
+	__UNMAP_POOL(2),
+	#if IS_ENABLED(CONFIG_DMA_ENGINE_RAID)
+	__UNMAP_POOL(16),
+	__UNMAP_POOL(128),
+	__UNMAP_POOL(256),
+	#endif
+};
+
+static struct dmaengine_unmap_pool *__get_unmap_pool(int nr)
+{
+	int order = get_count_order(nr);
+
+	switch (order) {
+	case 0 ... 1:
+		return &unmap_pool[0];
+#if IS_ENABLED(CONFIG_DMA_ENGINE_RAID)
+	case 2 ... 4:
+		return &unmap_pool[1];
+	case 5 ... 7:
+		return &unmap_pool[2];
+	case 8:
+		return &unmap_pool[3];
+#endif
+	default:
+		BUG();
+		return NULL;
+	}
+}
+
+static void dmaengine_unmap(struct kref *kref)
+{
+	struct dmaengine_unmap_data *unmap = container_of(kref, typeof(*unmap), kref);
+	struct device *dev = unmap->dev;
+	int cnt, i;
+
+	cnt = unmap->to_cnt;
+	for (i = 0; i < cnt; i++)
+		dma_unmap_page(dev, unmap->addr[i], unmap->len,
+			       DMA_TO_DEVICE);
+	cnt += unmap->from_cnt;
+	for (; i < cnt; i++)
+		dma_unmap_page(dev, unmap->addr[i], unmap->len,
+			       DMA_FROM_DEVICE);
+	cnt += unmap->bidi_cnt;
+	for (; i < cnt; i++) {
+		if (unmap->addr[i] == 0)
+			continue;
+		dma_unmap_page(dev, unmap->addr[i], unmap->len,
+			       DMA_BIDIRECTIONAL);
+	}
+	cnt = unmap->map_cnt;
+	mempool_free(unmap, __get_unmap_pool(cnt)->pool);
+}
+
+void dmaengine_unmap_put(struct dmaengine_unmap_data *unmap)
+{
+	if (unmap)
+		kref_put(&unmap->kref, dmaengine_unmap);
+}
+EXPORT_SYMBOL_GPL(dmaengine_unmap_put);
+
+static void dmaengine_destroy_unmap_pool(void)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(unmap_pool); i++) {
+		struct dmaengine_unmap_pool *p = &unmap_pool[i];
+
+		mempool_destroy(p->pool);
+		p->pool = NULL;
+		kmem_cache_destroy(p->cache);
+		p->cache = NULL;
+	}
+}
+
+static int __init dmaengine_init_unmap_pool(void)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(unmap_pool); i++) {
+		struct dmaengine_unmap_pool *p = &unmap_pool[i];
+		size_t size;
+
+		size = sizeof(struct dmaengine_unmap_data) +
+		       sizeof(dma_addr_t) * p->size;
+
+		p->cache = kmem_cache_create(p->name, size, 0,
+					     SLAB_HWCACHE_ALIGN, NULL);
+		if (!p->cache)
+			break;
+		p->pool = mempool_create_slab_pool(1, p->cache);
+		if (!p->pool)
+			break;
+	}
+
+	if (i == ARRAY_SIZE(unmap_pool))
+		return 0;
+
+	dmaengine_destroy_unmap_pool();
+	return -ENOMEM;
+}
+
+struct dmaengine_unmap_data *
+dmaengine_get_unmap_data(struct device *dev, int nr, gfp_t flags)
+{
+	struct dmaengine_unmap_data *unmap;
+
+	unmap = mempool_alloc(__get_unmap_pool(nr)->pool, flags);
+	if (!unmap)
+		return NULL;
+
+	memset(unmap, 0, sizeof(*unmap));
+	kref_init(&unmap->kref);
+	unmap->dev = dev;
+	unmap->map_cnt = nr;
+
+	return unmap;
+}
+EXPORT_SYMBOL(dmaengine_get_unmap_data);
+
+void dma_async_tx_descriptor_init(struct dma_async_tx_descriptor *tx,
+	struct dma_chan *chan)
+{
+	tx->chan = chan;
+	#ifdef CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH
+	spin_lock_init(&tx->lock);
+	#endif
+}
+EXPORT_SYMBOL(dma_async_tx_descriptor_init);
+
+/* dma_wait_for_async_tx - spin wait for a transaction to complete
+ * @tx: in-flight transaction to wait on
+ */
+enum dma_status
+dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx)
+{
+	unsigned long dma_sync_wait_timeout = jiffies + msecs_to_jiffies(5000);
+
+	if (!tx)
+		return DMA_COMPLETE;
+
+	while (tx->cookie == -EBUSY) {
+		if (time_after_eq(jiffies, dma_sync_wait_timeout)) {
+			dev_err(tx->chan->device->dev,
+				"%s timeout waiting for descriptor submission\n",
+				__func__);
+			return DMA_ERROR;
+		}
+		cpu_relax();
+	}
+	return dma_sync_wait(tx->chan, tx->cookie);
+}
+EXPORT_SYMBOL_GPL(dma_wait_for_async_tx);
+
+/* dma_run_dependencies - helper routine for dma drivers to process
+ *	(start) dependent operations on their target channel
+ * @tx: transaction with dependencies
+ */
+void dma_run_dependencies(struct dma_async_tx_descriptor *tx)
+{
+	struct dma_async_tx_descriptor *dep = txd_next(tx);
+	struct dma_async_tx_descriptor *dep_next;
+	struct dma_chan *chan;
+
+	if (!dep)
+		return;
+
+	/* we'll submit tx->next now, so clear the link */
+	txd_clear_next(tx);
+	chan = dep->chan;
+
+	/* keep submitting up until a channel switch is detected
+	 * in that case we will be called again as a result of
+	 * processing the interrupt from async_tx_channel_switch
+	 */
+	for (; dep; dep = dep_next) {
+		txd_lock(dep);
+		txd_clear_parent(dep);
+		dep_next = txd_next(dep);
+		if (dep_next && dep_next->chan == chan)
+			txd_clear_next(dep); /* ->next will be submitted */
+		else
+			dep_next = NULL; /* submit current dep and terminate */
+		txd_unlock(dep);
+
+		dep->tx_submit(dep);
+	}
+
+	chan->device->device_issue_pending(chan);
+}
+EXPORT_SYMBOL_GPL(dma_run_dependencies);
+
+static int __init dma_bus_init(void)
+{
+	int err = dmaengine_init_unmap_pool();
+
+	if (err)
+		return err;
+	return class_register(&dma_devclass);
+}
+arch_initcall(dma_bus_init);
+
+
diff --git a/kern/drivers/dma/dmaengine.h b/kern/drivers/dma/dmaengine.h
new file mode 100644
index 0000000..501c0b0
--- /dev/null
+++ b/kern/drivers/dma/dmaengine.h
@@ -0,0 +1,174 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * The contents of this file are private to DMA engine drivers, and is not
+ * part of the API to be used by DMA engine users.
+ */
+#ifndef DMAENGINE_H
+#define DMAENGINE_H
+
+#include <linux/bug.h>
+#include <linux/dmaengine.h>
+
+/**
+ * dma_cookie_init - initialize the cookies for a DMA channel
+ * @chan: dma channel to initialize
+ */
+static inline void dma_cookie_init(struct dma_chan *chan)
+{
+	chan->cookie = DMA_MIN_COOKIE;
+	chan->completed_cookie = DMA_MIN_COOKIE;
+}
+
+/**
+ * dma_cookie_assign - assign a DMA engine cookie to the descriptor
+ * @tx: descriptor needing cookie
+ *
+ * Assign a unique non-zero per-channel cookie to the descriptor.
+ * Note: caller is expected to hold a lock to prevent concurrency.
+ */
+static inline dma_cookie_t dma_cookie_assign(struct dma_async_tx_descriptor *tx)
+{
+	struct dma_chan *chan = tx->chan;
+	dma_cookie_t cookie;
+
+	cookie = chan->cookie + 1;
+	if (cookie < DMA_MIN_COOKIE)
+		cookie = DMA_MIN_COOKIE;
+	tx->cookie = chan->cookie = cookie;
+
+	return cookie;
+}
+
+/**
+ * dma_cookie_complete - complete a descriptor
+ * @tx: descriptor to complete
+ *
+ * Mark this descriptor complete by updating the channels completed
+ * cookie marker.  Zero the descriptors cookie to prevent accidental
+ * repeated completions.
+ *
+ * Note: caller is expected to hold a lock to prevent concurrency.
+ */
+static inline void dma_cookie_complete(struct dma_async_tx_descriptor *tx)
+{
+	BUG_ON(tx->cookie < DMA_MIN_COOKIE);
+	tx->chan->completed_cookie = tx->cookie;
+	tx->cookie = 0;
+}
+
+/**
+ * dma_cookie_status - report cookie status
+ * @chan: dma channel
+ * @cookie: cookie we are interested in
+ * @state: dma_tx_state structure to return last/used cookies
+ *
+ * Report the status of the cookie, filling in the state structure if
+ * non-NULL.  No locking is required.
+ */
+static inline enum dma_status dma_cookie_status(struct dma_chan *chan,
+	dma_cookie_t cookie, struct dma_tx_state *state)
+{
+	dma_cookie_t used, complete;
+
+	used = chan->cookie;
+	complete = chan->completed_cookie;
+	barrier();
+	if (state) {
+		state->last = complete;
+		state->used = used;
+		state->residue = 0;
+	}
+	return dma_async_is_complete(cookie, complete, used);
+}
+
+static inline void dma_set_residue(struct dma_tx_state *state, u32 residue)
+{
+	if (state)
+		state->residue = residue;
+}
+
+struct dmaengine_desc_callback {
+	dma_async_tx_callback callback;
+	dma_async_tx_callback_result callback_result;
+	void *callback_param;
+};
+
+/**
+ * dmaengine_desc_get_callback - get the passed in callback function
+ * @tx: tx descriptor
+ * @cb: temp struct to hold the callback info
+ *
+ * Fill the passed in cb struct with what's available in the passed in
+ * tx descriptor struct
+ * No locking is required.
+ */
+static inline void
+dmaengine_desc_get_callback(struct dma_async_tx_descriptor *tx,
+			    struct dmaengine_desc_callback *cb)
+{
+	cb->callback = tx->callback;
+	cb->callback_result = tx->callback_result;
+	cb->callback_param = tx->callback_param;
+}
+
+/**
+ * dmaengine_desc_callback_invoke - call the callback function in cb struct
+ * @cb: temp struct that is holding the callback info
+ * @result: transaction result
+ *
+ * Call the callback function provided in the cb struct with the parameter
+ * in the cb struct.
+ * Locking is dependent on the driver.
+ */
+static inline void
+dmaengine_desc_callback_invoke(struct dmaengine_desc_callback *cb,
+			       const struct dmaengine_result *result)
+{
+	struct dmaengine_result dummy_result = {
+		.result = DMA_TRANS_NOERROR,
+		.residue = 0
+	};
+
+	if (cb->callback_result) {
+		if (!result)
+			result = &dummy_result;
+		cb->callback_result(cb->callback_param, result);
+	} else if (cb->callback) {
+		cb->callback(cb->callback_param);
+	}
+}
+
+/**
+ * dmaengine_desc_get_callback_invoke - get the callback in tx descriptor and
+ * 					then immediately call the callback.
+ * @tx: dma async tx descriptor
+ * @result: transaction result
+ *
+ * Call dmaengine_desc_get_callback() and dmaengine_desc_callback_invoke()
+ * in a single function since no work is necessary in between for the driver.
+ * Locking is dependent on the driver.
+ */
+static inline void
+dmaengine_desc_get_callback_invoke(struct dma_async_tx_descriptor *tx,
+				   const struct dmaengine_result *result)
+{
+	struct dmaengine_desc_callback cb;
+
+	dmaengine_desc_get_callback(tx, &cb);
+	dmaengine_desc_callback_invoke(&cb, result);
+}
+
+/**
+ * dmaengine_desc_callback_valid - verify the callback is valid in cb
+ * @cb: callback info struct
+ *
+ * Return a bool that verifies whether callback in cb is valid or not.
+ * No locking is required.
+ */
+static inline bool
+dmaengine_desc_callback_valid(struct dmaengine_desc_callback *cb)
+{
+	return (cb->callback) ? true : false;
+}
+
+#endif
diff --git a/kern/include/linux/dmaengine.h b/kern/include/linux/dmaengine.h
new file mode 100644
index 0000000..d49ec5c
--- /dev/null
+++ b/kern/include/linux/dmaengine.h
@@ -0,0 +1,1434 @@
+/*
+ * Copyright(c) 2004 - 2006 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * The full GNU General Public License is included in this distribution in the
+ * file called COPYING.
+ */
+#ifndef LINUX_DMAENGINE_H
+#define LINUX_DMAENGINE_H
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/uio.h>
+#include <linux/bug.h>
+#include <linux/scatterlist.h>
+#include <linux/bitmap.h>
+#include <linux/types.h>
+#include <asm/page.h>
+
+/**
+ * typedef dma_cookie_t - an opaque DMA cookie
+ *
+ * if dma_cookie_t is >0 it's a DMA request cookie, <0 it's an error code
+ */
+typedef s32 dma_cookie_t;
+#define DMA_MIN_COOKIE	1
+
+static inline int dma_submit_error(dma_cookie_t cookie)
+{
+	return cookie < 0 ? cookie : 0;
+}
+
+/**
+ * enum dma_status - DMA transaction status
+ * @DMA_COMPLETE: transaction completed
+ * @DMA_IN_PROGRESS: transaction not yet processed
+ * @DMA_PAUSED: transaction is paused
+ * @DMA_ERROR: transaction failed
+ */
+enum dma_status {
+	DMA_COMPLETE,
+	DMA_IN_PROGRESS,
+	DMA_PAUSED,
+	DMA_ERROR,
+};
+
+/**
+ * enum dma_transaction_type - DMA transaction types/indexes
+ *
+ * Note: The DMA_ASYNC_TX capability is not to be set by drivers.  It is
+ * automatically set as dma devices are registered.
+ */
+enum dma_transaction_type {
+	DMA_MEMCPY,
+	DMA_XOR,
+	DMA_PQ,
+	DMA_XOR_VAL,
+	DMA_PQ_VAL,
+	DMA_MEMSET,
+	DMA_MEMSET_SG,
+	DMA_INTERRUPT,
+	DMA_PRIVATE,
+	DMA_ASYNC_TX,
+	DMA_SLAVE,
+	DMA_CYCLIC,
+	DMA_INTERLEAVE,
+/* last transaction type for creation of the capabilities mask */
+	DMA_TX_TYPE_END,
+};
+
+/**
+ * enum dma_transfer_direction - dma transfer mode and direction indicator
+ * @DMA_MEM_TO_MEM: Async/Memcpy mode
+ * @DMA_MEM_TO_DEV: Slave mode & From Memory to Device
+ * @DMA_DEV_TO_MEM: Slave mode & From Device to Memory
+ * @DMA_DEV_TO_DEV: Slave mode & From Device to Device
+ */
+enum dma_transfer_direction {
+	DMA_MEM_TO_MEM,
+	DMA_MEM_TO_DEV,
+	DMA_DEV_TO_MEM,
+	DMA_DEV_TO_DEV,
+	DMA_TRANS_NONE,
+};
+
+/**
+ * Interleaved Transfer Request
+ * ----------------------------
+ * A chunk is collection of contiguous bytes to be transfered.
+ * The gap(in bytes) between two chunks is called inter-chunk-gap(ICG).
+ * ICGs may or maynot change between chunks.
+ * A FRAME is the smallest series of contiguous {chunk,icg} pairs,
+ *  that when repeated an integral number of times, specifies the transfer.
+ * A transfer template is specification of a Frame, the number of times
+ *  it is to be repeated and other per-transfer attributes.
+ *
+ * Practically, a client driver would have ready a template for each
+ *  type of transfer it is going to need during its lifetime and
+ *  set only 'src_start' and 'dst_start' before submitting the requests.
+ *
+ *
+ *  |      Frame-1        |       Frame-2       | ~ |       Frame-'numf'  |
+ *  |====....==.===...=...|====....==.===...=...| ~ |====....==.===...=...|
+ *
+ *    ==  Chunk size
+ *    ... ICG
+ */
+
+/**
+ * struct data_chunk - Element of scatter-gather list that makes a frame.
+ * @size: Number of bytes to read from source.
+ *	  size_dst := fn(op, size_src), so doesn't mean much for destination.
+ * @icg: Number of bytes to jump after last src/dst address of this
+ *	 chunk and before first src/dst address for next chunk.
+ *	 Ignored for dst(assumed 0), if dst_inc is true and dst_sgl is false.
+ *	 Ignored for src(assumed 0), if src_inc is true and src_sgl is false.
+ * @dst_icg: Number of bytes to jump after last dst address of this
+ *	 chunk and before the first dst address for next chunk.
+ *	 Ignored if dst_inc is true and dst_sgl is false.
+ * @src_icg: Number of bytes to jump after last src address of this
+ *	 chunk and before the first src address for next chunk.
+ *	 Ignored if src_inc is true and src_sgl is false.
+ */
+struct data_chunk {
+	size_t size;
+	size_t icg;
+	size_t dst_icg;
+	size_t src_icg;
+};
+
+/**
+ * struct dma_interleaved_template - Template to convey DMAC the transfer pattern
+ *	 and attributes.
+ * @src_start: Bus address of source for the first chunk.
+ * @dst_start: Bus address of destination for the first chunk.
+ * @dir: Specifies the type of Source and Destination.
+ * @src_inc: If the source address increments after reading from it.
+ * @dst_inc: If the destination address increments after writing to it.
+ * @src_sgl: If the 'icg' of sgl[] applies to Source (scattered read).
+ *		Otherwise, source is read contiguously (icg ignored).
+ *		Ignored if src_inc is false.
+ * @dst_sgl: If the 'icg' of sgl[] applies to Destination (scattered write).
+ *		Otherwise, destination is filled contiguously (icg ignored).
+ *		Ignored if dst_inc is false.
+ * @numf: Number of frames in this template.
+ * @frame_size: Number of chunks in a frame i.e, size of sgl[].
+ * @sgl: Array of {chunk,icg} pairs that make up a frame.
+ */
+struct dma_interleaved_template {
+	dma_addr_t src_start;
+	dma_addr_t dst_start;
+	enum dma_transfer_direction dir;
+	bool src_inc;
+	bool dst_inc;
+	bool src_sgl;
+	bool dst_sgl;
+	size_t numf;
+	size_t frame_size;
+	struct data_chunk sgl[0];
+};
+
+/**
+ * enum dma_ctrl_flags - DMA flags to augment operation preparation,
+ *  control completion, and communicate status.
+ * @DMA_PREP_INTERRUPT - trigger an interrupt (callback) upon completion of
+ *  this transaction
+ * @DMA_CTRL_ACK - if clear, the descriptor cannot be reused until the client
+ *  acknowledges receipt, i.e. has has a chance to establish any dependency
+ *  chains
+ * @DMA_PREP_PQ_DISABLE_P - prevent generation of P while generating Q
+ * @DMA_PREP_PQ_DISABLE_Q - prevent generation of Q while generating P
+ * @DMA_PREP_CONTINUE - indicate to a driver that it is reusing buffers as
+ *  sources that were the result of a previous operation, in the case of a PQ
+ *  operation it continues the calculation with new sources
+ * @DMA_PREP_FENCE - tell the driver that subsequent operations depend
+ *  on the result of this operation
+ * @DMA_CTRL_REUSE: client can reuse the descriptor and submit again till
+ *  cleared or freed
+ * @DMA_PREP_CMD: tell the driver that the data passed to DMA API is command
+ *  data and the descriptor should be in different format from normal
+ *  data descriptors.
+ */
+enum dma_ctrl_flags {
+	DMA_PREP_INTERRUPT = (1 << 0),
+	DMA_CTRL_ACK = (1 << 1),
+	DMA_PREP_PQ_DISABLE_P = (1 << 2),
+	DMA_PREP_PQ_DISABLE_Q = (1 << 3),
+	DMA_PREP_CONTINUE = (1 << 4),
+	DMA_PREP_FENCE = (1 << 5),
+	DMA_CTRL_REUSE = (1 << 6),
+	DMA_PREP_CMD = (1 << 7),
+};
+
+/**
+ * enum sum_check_bits - bit position of pq_check_flags
+ */
+enum sum_check_bits {
+	SUM_CHECK_P = 0,
+	SUM_CHECK_Q = 1,
+};
+
+/**
+ * enum pq_check_flags - result of async_{xor,pq}_zero_sum operations
+ * @SUM_CHECK_P_RESULT - 1 if xor zero sum error, 0 otherwise
+ * @SUM_CHECK_Q_RESULT - 1 if reed-solomon zero sum error, 0 otherwise
+ */
+enum sum_check_flags {
+	SUM_CHECK_P_RESULT = (1 << SUM_CHECK_P),
+	SUM_CHECK_Q_RESULT = (1 << SUM_CHECK_Q),
+};
+
+
+/**
+ * dma_cap_mask_t - capabilities bitmap modeled after cpumask_t.
+ * See linux/cpumask.h
+ */
+typedef struct { DECLARE_BITMAP(bits, DMA_TX_TYPE_END); } dma_cap_mask_t;
+
+/**
+ * struct dma_chan_percpu - the per-CPU part of struct dma_chan
+ * @memcpy_count: transaction counter
+ * @bytes_transferred: byte counter
+ */
+
+struct dma_chan_percpu {
+	/* stats */
+	unsigned long memcpy_count;
+	unsigned long bytes_transferred;
+};
+
+/**
+ * struct dma_router - DMA router structure
+ * @dev: pointer to the DMA router device
+ * @route_free: function to be called when the route can be disconnected
+ */
+struct dma_router {
+	struct device *dev;
+	void (*route_free)(struct device *dev, void *route_data);
+};
+
+/**
+ * struct dma_chan - devices supply DMA channels, clients use them
+ * @device: ptr to the dma device who supplies this channel, always !%NULL
+ * @cookie: last cookie value returned to client
+ * @completed_cookie: last completed cookie for this channel
+ * @chan_id: channel ID for sysfs
+ * @dev: class device for sysfs
+ * @device_node: used to add this to the device chan list
+ * @local: per-cpu pointer to a struct dma_chan_percpu
+ * @client_count: how many clients are using this channel
+ * @table_count: number of appearances in the mem-to-mem allocation table
+ * @router: pointer to the DMA router structure
+ * @route_data: channel specific data for the router
+ * @private: private data for certain client-channel associations
+ */
+struct dma_chan {
+	struct dma_device *device;
+	dma_cookie_t cookie;
+	dma_cookie_t completed_cookie;
+
+	/* sysfs */
+	int chan_id;
+	struct dma_chan_dev *dev;
+
+	struct list_head device_node;
+	struct dma_chan_percpu __percpu *local;
+	int client_count;
+	int table_count;
+
+	/* DMA router */
+	struct dma_router *router;
+	void *route_data;
+
+	void *private;
+};
+
+/**
+ * struct dma_chan_dev - relate sysfs device node to backing channel device
+ * @chan: driver channel device
+ * @device: sysfs device
+ * @dev_id: parent dma_device dev_id
+ * @idr_ref: reference count to gate release of dma_device dev_id
+ */
+struct dma_chan_dev {
+	struct dma_chan *chan;
+	struct device device;
+	int dev_id;
+	atomic_t *idr_ref;
+};
+
+/**
+ * enum dma_slave_buswidth - defines bus width of the DMA slave
+ * device, source or target buses
+ */
+enum dma_slave_buswidth {
+	DMA_SLAVE_BUSWIDTH_UNDEFINED = 0,
+	DMA_SLAVE_BUSWIDTH_1_BYTE = 1,
+	DMA_SLAVE_BUSWIDTH_2_BYTES = 2,
+	DMA_SLAVE_BUSWIDTH_3_BYTES = 3,
+	DMA_SLAVE_BUSWIDTH_4_BYTES = 4,
+	DMA_SLAVE_BUSWIDTH_8_BYTES = 8,
+	DMA_SLAVE_BUSWIDTH_16_BYTES = 16,
+	DMA_SLAVE_BUSWIDTH_32_BYTES = 32,
+	DMA_SLAVE_BUSWIDTH_64_BYTES = 64,
+};
+
+/**
+ * struct dma_slave_config - dma slave channel runtime config
+ * @direction: whether the data shall go in or out on this slave
+ * channel, right now. DMA_MEM_TO_DEV and DMA_DEV_TO_MEM are
+ * legal values. DEPRECATED, drivers should use the direction argument
+ * to the device_prep_slave_sg and device_prep_dma_cyclic functions or
+ * the dir field in the dma_interleaved_template structure.
+ * @src_addr: this is the physical address where DMA slave data
+ * should be read (RX), if the source is memory this argument is
+ * ignored.
+ * @dst_addr: this is the physical address where DMA slave data
+ * should be written (TX), if the source is memory this argument
+ * is ignored.
+ * @src_addr_width: this is the width in bytes of the source (RX)
+ * register where DMA data shall be read. If the source
+ * is memory this may be ignored depending on architecture.
+ * Legal values: 1, 2, 3, 4, 8, 16, 32, 64.
+ * @dst_addr_width: same as src_addr_width but for destination
+ * target (TX) mutatis mutandis.
+ * @src_maxburst: the maximum number of words (note: words, as in
+ * units of the src_addr_width member, not bytes) that can be sent
+ * in one burst to the device. Typically something like half the
+ * FIFO depth on I/O peripherals so you don't overflow it. This
+ * may or may not be applicable on memory sources.
+ * @dst_maxburst: same as src_maxburst but for destination target
+ * mutatis mutandis.
+ * @src_port_window_size: The length of the register area in words the data need
+ * to be accessed on the device side. It is only used for devices which is using
+ * an area instead of a single register to receive the data. Typically the DMA
+ * loops in this area in order to transfer the data.
+ * @dst_port_window_size: same as src_port_window_size but for the destination
+ * port.
+ * @device_fc: Flow Controller Settings. Only valid for slave channels. Fill
+ * with 'true' if peripheral should be flow controller. Direction will be
+ * selected at Runtime.
+ * @slave_id: Slave requester id. Only valid for slave channels. The dma
+ * slave peripheral will have unique id as dma requester which need to be
+ * pass as slave config.
+ *
+ * This struct is passed in as configuration data to a DMA engine
+ * in order to set up a certain channel for DMA transport at runtime.
+ * The DMA device/engine has to provide support for an additional
+ * callback in the dma_device structure, device_config and this struct
+ * will then be passed in as an argument to the function.
+ *
+ * The rationale for adding configuration information to this struct is as
+ * follows: if it is likely that more than one DMA slave controllers in
+ * the world will support the configuration option, then make it generic.
+ * If not: if it is fixed so that it be sent in static from the platform
+ * data, then prefer to do that.
+ */
+struct dma_slave_config {
+	enum dma_transfer_direction direction;
+	phys_addr_t src_addr;
+	phys_addr_t dst_addr;
+	enum dma_slave_buswidth src_addr_width;
+	enum dma_slave_buswidth dst_addr_width;
+	u32 src_maxburst;
+	u32 dst_maxburst;
+	u32 src_port_window_size;
+	u32 dst_port_window_size;
+	bool device_fc;
+	unsigned int slave_id;
+};
+
+/**
+ * enum dma_residue_granularity - Granularity of the reported transfer residue
+ * @DMA_RESIDUE_GRANULARITY_DESCRIPTOR: Residue reporting is not support. The
+ *  DMA channel is only able to tell whether a descriptor has been completed or
+ *  not, which means residue reporting is not supported by this channel. The
+ *  residue field of the dma_tx_state field will always be 0.
+ * @DMA_RESIDUE_GRANULARITY_SEGMENT: Residue is updated after each successfully
+ *  completed segment of the transfer (For cyclic transfers this is after each
+ *  period). This is typically implemented by having the hardware generate an
+ *  interrupt after each transferred segment and then the drivers updates the
+ *  outstanding residue by the size of the segment. Another possibility is if
+ *  the hardware supports scatter-gather and the segment descriptor has a field
+ *  which gets set after the segment has been completed. The driver then counts
+ *  the number of segments without the flag set to compute the residue.
+ * @DMA_RESIDUE_GRANULARITY_BURST: Residue is updated after each transferred
+ *  burst. This is typically only supported if the hardware has a progress
+ *  register of some sort (E.g. a register with the current read/write address
+ *  or a register with the amount of bursts/beats/bytes that have been
+ *  transferred or still need to be transferred).
+ */
+enum dma_residue_granularity {
+	DMA_RESIDUE_GRANULARITY_DESCRIPTOR = 0,
+	DMA_RESIDUE_GRANULARITY_SEGMENT = 1,
+	DMA_RESIDUE_GRANULARITY_BURST = 2,
+};
+
+/**
+ * struct dma_slave_caps - expose capabilities of a slave channel only
+ * @src_addr_widths: bit mask of src addr widths the channel supports.
+ *	Width is specified in bytes, e.g. for a channel supporting
+ *	a width of 4 the mask should have BIT(4) set.
+ * @dst_addr_widths: bit mask of dst addr widths the channel supports
+ * @directions: bit mask of slave directions the channel supports.
+ *	Since the enum dma_transfer_direction is not defined as bit flag for
+ *	each type, the dma controller should set BIT(<TYPE>) and same
+ *	should be checked by controller as well
+ * @max_burst: max burst capability per-transfer
+ * @cmd_pause: true, if pause is supported (i.e. for reading residue or
+ *	       for resume later)
+ * @cmd_resume: true, if resume is supported
+ * @cmd_terminate: true, if terminate cmd is supported
+ * @residue_granularity: granularity of the reported transfer residue
+ * @descriptor_reuse: if a descriptor can be reused by client and
+ * resubmitted multiple times
+ */
+struct dma_slave_caps {
+	u32 src_addr_widths;
+	u32 dst_addr_widths;
+	u32 directions;
+	u32 max_burst;
+	bool cmd_pause;
+	bool cmd_resume;
+	bool cmd_terminate;
+	enum dma_residue_granularity residue_granularity;
+	bool descriptor_reuse;
+};
+
+static inline const char *dma_chan_name(struct dma_chan *chan)
+{
+	return dev_name(&chan->dev->device);
+}
+
+void dma_chan_cleanup(struct kref *kref);
+
+/**
+ * typedef dma_filter_fn - callback filter for dma_request_channel
+ * @chan: channel to be reviewed
+ * @filter_param: opaque parameter passed through dma_request_channel
+ *
+ * When this optional parameter is specified in a call to dma_request_channel a
+ * suitable channel is passed to this routine for further dispositioning before
+ * being returned.  Where 'suitable' indicates a non-busy channel that
+ * satisfies the given capability mask.  It returns 'true' to indicate that the
+ * channel is suitable.
+ */
+typedef bool (*dma_filter_fn)(struct dma_chan *chan, void *filter_param);
+
+typedef void (*dma_async_tx_callback)(void *dma_async_param);
+
+enum dmaengine_tx_result {
+	DMA_TRANS_NOERROR = 0,		/* SUCCESS */
+	DMA_TRANS_READ_FAILED,		/* Source DMA read failed */
+	DMA_TRANS_WRITE_FAILED,		/* Destination DMA write failed */
+	DMA_TRANS_ABORTED,		/* Op never submitted / aborted */
+};
+
+struct dmaengine_result {
+	enum dmaengine_tx_result result;
+	u32 residue;
+};
+
+typedef void (*dma_async_tx_callback_result)(void *dma_async_param,
+				const struct dmaengine_result *result);
+
+struct dmaengine_unmap_data {
+#if IS_ENABLED(CONFIG_DMA_ENGINE_RAID)
+	u16 map_cnt;
+#else
+	u8 map_cnt;
+#endif
+	u8 to_cnt;
+	u8 from_cnt;
+	u8 bidi_cnt;
+	struct device *dev;
+	struct kref kref;
+	size_t len;
+	dma_addr_t addr[0];
+};
+
+/**
+ * struct dma_async_tx_descriptor - async transaction descriptor
+ * ---dma generic offload fields---
+ * @cookie: tracking cookie for this transaction, set to -EBUSY if
+ *	this tx is sitting on a dependency list
+ * @flags: flags to augment operation preparation, control completion, and
+ * 	communicate status
+ * @phys: physical address of the descriptor
+ * @chan: target channel for this operation
+ * @tx_submit: accept the descriptor, assign ordered cookie and mark the
+ * descriptor pending. To be pushed on .issue_pending() call
+ * @callback: routine to call after this operation is complete
+ * @callback_param: general parameter to pass to the callback routine
+ * ---async_tx api specific fields---
+ * @next: at completion submit this descriptor
+ * @parent: pointer to the next level up in the dependency chain
+ * @lock: protect the parent and next pointers
+ */
+struct dma_async_tx_descriptor {
+	dma_cookie_t cookie;
+	enum dma_ctrl_flags flags; /* not a 'long' to pack with cookie */
+	dma_addr_t phys;
+	struct dma_chan *chan;
+	dma_cookie_t (*tx_submit)(struct dma_async_tx_descriptor *tx);
+	int (*desc_free)(struct dma_async_tx_descriptor *tx);
+	dma_async_tx_callback callback;
+	dma_async_tx_callback_result callback_result;
+	void *callback_param;
+	struct dmaengine_unmap_data *unmap;
+#ifdef CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH
+	struct dma_async_tx_descriptor *next;
+	struct dma_async_tx_descriptor *parent;
+	spinlock_t lock;
+#endif
+};
+
+#ifdef CONFIG_DMA_ENGINE
+static inline void dma_set_unmap(struct dma_async_tx_descriptor *tx,
+				 struct dmaengine_unmap_data *unmap)
+{
+	kref_get(&unmap->kref);
+	tx->unmap = unmap;
+}
+
+struct dmaengine_unmap_data *
+dmaengine_get_unmap_data(struct device *dev, int nr, gfp_t flags);
+void dmaengine_unmap_put(struct dmaengine_unmap_data *unmap);
+#else
+static inline void dma_set_unmap(struct dma_async_tx_descriptor *tx,
+				 struct dmaengine_unmap_data *unmap)
+{
+}
+static inline struct dmaengine_unmap_data *
+dmaengine_get_unmap_data(struct device *dev, int nr, gfp_t flags)
+{
+	return NULL;
+}
+static inline void dmaengine_unmap_put(struct dmaengine_unmap_data *unmap)
+{
+}
+#endif
+
+static inline void dma_descriptor_unmap(struct dma_async_tx_descriptor *tx)
+{
+	if (tx->unmap) {
+		dmaengine_unmap_put(tx->unmap);
+		tx->unmap = NULL;
+	}
+}
+
+#ifndef CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH
+static inline void txd_lock(struct dma_async_tx_descriptor *txd)
+{
+}
+static inline void txd_unlock(struct dma_async_tx_descriptor *txd)
+{
+}
+static inline void txd_chain(struct dma_async_tx_descriptor *txd, struct dma_async_tx_descriptor *next)
+{
+	BUG();
+}
+static inline void txd_clear_parent(struct dma_async_tx_descriptor *txd)
+{
+}
+static inline void txd_clear_next(struct dma_async_tx_descriptor *txd)
+{
+}
+static inline struct dma_async_tx_descriptor *txd_next(struct dma_async_tx_descriptor *txd)
+{
+	return NULL;
+}
+static inline struct dma_async_tx_descriptor *txd_parent(struct dma_async_tx_descriptor *txd)
+{
+	return NULL;
+}
+
+#else
+static inline void txd_lock(struct dma_async_tx_descriptor *txd)
+{
+	spin_lock_bh(&txd->lock);
+}
+static inline void txd_unlock(struct dma_async_tx_descriptor *txd)
+{
+	spin_unlock_bh(&txd->lock);
+}
+static inline void txd_chain(struct dma_async_tx_descriptor *txd, struct dma_async_tx_descriptor *next)
+{
+	txd->next = next;
+	next->parent = txd;
+}
+static inline void txd_clear_parent(struct dma_async_tx_descriptor *txd)
+{
+	txd->parent = NULL;
+}
+static inline void txd_clear_next(struct dma_async_tx_descriptor *txd)
+{
+	txd->next = NULL;
+}
+static inline struct dma_async_tx_descriptor *txd_parent(struct dma_async_tx_descriptor *txd)
+{
+	return txd->parent;
+}
+static inline struct dma_async_tx_descriptor *txd_next(struct dma_async_tx_descriptor *txd)
+{
+	return txd->next;
+}
+#endif
+
+/**
+ * struct dma_tx_state - filled in to report the status of
+ * a transfer.
+ * @last: last completed DMA cookie
+ * @used: last issued DMA cookie (i.e. the one in progress)
+ * @residue: the remaining number of bytes left to transmit
+ *	on the selected transfer for states DMA_IN_PROGRESS and
+ *	DMA_PAUSED if this is implemented in the driver, else 0
+ */
+struct dma_tx_state {
+	dma_cookie_t last;
+	dma_cookie_t used;
+	u32 residue;
+};
+
+/**
+ * enum dmaengine_alignment - defines alignment of the DMA async tx
+ * buffers
+ */
+enum dmaengine_alignment {
+	DMAENGINE_ALIGN_1_BYTE = 0,
+	DMAENGINE_ALIGN_2_BYTES = 1,
+	DMAENGINE_ALIGN_4_BYTES = 2,
+	DMAENGINE_ALIGN_8_BYTES = 3,
+	DMAENGINE_ALIGN_16_BYTES = 4,
+	DMAENGINE_ALIGN_32_BYTES = 5,
+	DMAENGINE_ALIGN_64_BYTES = 6,
+};
+
+/**
+ * struct dma_slave_map - associates slave device and it's slave channel with
+ * parameter to be used by a filter function
+ * @devname: name of the device
+ * @slave: slave channel name
+ * @param: opaque parameter to pass to struct dma_filter.fn
+ */
+struct dma_slave_map {
+	const char *devname;
+	const char *slave;
+	void *param;
+};
+
+/**
+ * struct dma_filter - information for slave device/channel to filter_fn/param
+ * mapping
+ * @fn: filter function callback
+ * @mapcnt: number of slave device/channel in the map
+ * @map: array of channel to filter mapping data
+ */
+struct dma_filter {
+	dma_filter_fn fn;
+	int mapcnt;
+	const struct dma_slave_map *map;
+};
+
+/**
+ * struct dma_device - info on the entity supplying DMA services
+ * @chancnt: how many DMA channels are supported
+ * @privatecnt: how many DMA channels are requested by dma_request_channel
+ * @channels: the list of struct dma_chan
+ * @global_node: list_head for global dma_device_list
+ * @filter: information for device/slave to filter function/param mapping
+ * @cap_mask: one or more dma_capability flags
+ * @max_xor: maximum number of xor sources, 0 if no capability
+ * @max_pq: maximum number of PQ sources and PQ-continue capability
+ * @copy_align: alignment shift for memcpy operations
+ * @xor_align: alignment shift for xor operations
+ * @pq_align: alignment shift for pq operations
+ * @fill_align: alignment shift for memset operations
+ * @dev_id: unique device ID
+ * @dev: struct device reference for dma mapping api
+ * @src_addr_widths: bit mask of src addr widths the device supports
+ *	Width is specified in bytes, e.g. for a device supporting
+ *	a width of 4 the mask should have BIT(4) set.
+ * @dst_addr_widths: bit mask of dst addr widths the device supports
+ * @directions: bit mask of slave directions the device supports.
+ *	Since the enum dma_transfer_direction is not defined as bit flag for
+ *	each type, the dma controller should set BIT(<TYPE>) and same
+ *	should be checked by controller as well
+ * @max_burst: max burst capability per-transfer
+ * @residue_granularity: granularity of the transfer residue reported
+ *	by tx_status
+ * @device_alloc_chan_resources: allocate resources and return the
+ *	number of allocated descriptors
+ * @device_free_chan_resources: release DMA channel's resources
+ * @device_prep_dma_memcpy: prepares a memcpy operation
+ * @device_prep_dma_xor: prepares a xor operation
+ * @device_prep_dma_xor_val: prepares a xor validation operation
+ * @device_prep_dma_pq: prepares a pq operation
+ * @device_prep_dma_pq_val: prepares a pqzero_sum operation
+ * @device_prep_dma_memset: prepares a memset operation
+ * @device_prep_dma_memset_sg: prepares a memset operation over a scatter list
+ * @device_prep_dma_interrupt: prepares an end of chain interrupt operation
+ * @device_prep_slave_sg: prepares a slave dma operation
+ * @device_prep_dma_cyclic: prepare a cyclic dma operation suitable for audio.
+ *	The function takes a buffer of size buf_len. The callback function will
+ *	be called after period_len bytes have been transferred.
+ * @device_prep_interleaved_dma: Transfer expression in a generic way.
+ * @device_prep_dma_imm_data: DMA's 8 byte immediate data to the dst address
+ * @device_config: Pushes a new configuration to a channel, return 0 or an error
+ *	code
+ * @device_pause: Pauses any transfer happening on a channel. Returns
+ *	0 or an error code
+ * @device_resume: Resumes any transfer on a channel previously
+ *	paused. Returns 0 or an error code
+ * @device_terminate_all: Aborts all transfers on a channel. Returns 0
+ *	or an error code
+ * @device_synchronize: Synchronizes the termination of a transfers to the
+ *  current context.
+ * @device_tx_status: poll for transaction completion, the optional
+ *	txstate parameter can be supplied with a pointer to get a
+ *	struct with auxiliary transfer status information, otherwise the call
+ *	will just return a simple status code
+ * @device_issue_pending: push pending transactions to hardware
+ * @descriptor_reuse: a submitted transfer can be resubmitted after completion
+ */
+struct dma_device {
+
+	unsigned int chancnt;
+	unsigned int privatecnt;
+	struct list_head channels;
+	struct list_head global_node;
+	struct dma_filter filter;
+	dma_cap_mask_t  cap_mask;
+	unsigned short max_xor;
+	unsigned short max_pq;
+	enum dmaengine_alignment copy_align;
+	enum dmaengine_alignment xor_align;
+	enum dmaengine_alignment pq_align;
+	enum dmaengine_alignment fill_align;
+	#define DMA_HAS_PQ_CONTINUE (1 << 15)
+
+	int dev_id;
+	struct device *dev;
+
+	u32 src_addr_widths;
+	u32 dst_addr_widths;
+	u32 directions;
+	u32 max_burst;
+	bool descriptor_reuse;
+	enum dma_residue_granularity residue_granularity;
+
+	int (*device_alloc_chan_resources)(struct dma_chan *chan);
+	void (*device_free_chan_resources)(struct dma_chan *chan);
+
+	struct dma_async_tx_descriptor *(*device_prep_dma_memcpy)(
+		struct dma_chan *chan, dma_addr_t dst, dma_addr_t src,
+		size_t len, unsigned long flags);
+	struct dma_async_tx_descriptor *(*device_prep_dma_xor)(
+		struct dma_chan *chan, dma_addr_t dst, dma_addr_t *src,
+		unsigned int src_cnt, size_t len, unsigned long flags);
+	struct dma_async_tx_descriptor *(*device_prep_dma_xor_val)(
+		struct dma_chan *chan, dma_addr_t *src,	unsigned int src_cnt,
+		size_t len, enum sum_check_flags *result, unsigned long flags);
+	struct dma_async_tx_descriptor *(*device_prep_dma_pq)(
+		struct dma_chan *chan, dma_addr_t *dst, dma_addr_t *src,
+		unsigned int src_cnt, const unsigned char *scf,
+		size_t len, unsigned long flags);
+	struct dma_async_tx_descriptor *(*device_prep_dma_pq_val)(
+		struct dma_chan *chan, dma_addr_t *pq, dma_addr_t *src,
+		unsigned int src_cnt, const unsigned char *scf, size_t len,
+		enum sum_check_flags *pqres, unsigned long flags);
+	struct dma_async_tx_descriptor *(*device_prep_dma_memset)(
+		struct dma_chan *chan, dma_addr_t dest, int value, size_t len,
+		unsigned long flags);
+	struct dma_async_tx_descriptor *(*device_prep_dma_memset_sg)(
+		struct dma_chan *chan, struct scatterlist *sg,
+		unsigned int nents, int value, unsigned long flags);
+	struct dma_async_tx_descriptor *(*device_prep_dma_interrupt)(
+		struct dma_chan *chan, unsigned long flags);
+
+	struct dma_async_tx_descriptor *(*device_prep_slave_sg)(
+		struct dma_chan *chan, struct scatterlist *sgl,
+		unsigned int sg_len, enum dma_transfer_direction direction,
+		unsigned long flags, void *context);
+	struct dma_async_tx_descriptor *(*device_prep_dma_cyclic)(
+		struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len,
+		size_t period_len, enum dma_transfer_direction direction,
+		unsigned long flags);
+	struct dma_async_tx_descriptor *(*device_prep_interleaved_dma)(
+		struct dma_chan *chan, struct dma_interleaved_template *xt,
+		unsigned long flags);
+	struct dma_async_tx_descriptor *(*device_prep_dma_imm_data)(
+		struct dma_chan *chan, dma_addr_t dst, u64 data,
+		unsigned long flags);
+
+	int (*device_config)(struct dma_chan *chan,
+			     struct dma_slave_config *config);
+	int (*device_pause)(struct dma_chan *chan);
+	int (*device_resume)(struct dma_chan *chan);
+	int (*device_terminate_all)(struct dma_chan *chan);
+	void (*device_synchronize)(struct dma_chan *chan);
+
+	enum dma_status (*device_tx_status)(struct dma_chan *chan,
+					    dma_cookie_t cookie,
+					    struct dma_tx_state *txstate);
+	void (*device_issue_pending)(struct dma_chan *chan);
+};
+
+static inline int dmaengine_slave_config(struct dma_chan *chan,
+					  struct dma_slave_config *config)
+{
+	if (chan->device->device_config)
+		return chan->device->device_config(chan, config);
+
+	return -ENOSYS;
+}
+
+static inline bool is_slave_direction(enum dma_transfer_direction direction)
+{
+	return (direction == DMA_MEM_TO_DEV) || (direction == DMA_DEV_TO_MEM);
+}
+
+static inline struct dma_async_tx_descriptor *dmaengine_prep_slave_single(
+	struct dma_chan *chan, dma_addr_t buf, size_t len,
+	enum dma_transfer_direction dir, unsigned long flags)
+{
+	struct scatterlist sg;
+	sg_init_table(&sg, 1);
+	sg_dma_address(&sg) = buf;
+	sg_dma_len(&sg) = len;
+
+	if (!chan || !chan->device || !chan->device->device_prep_slave_sg)
+		return NULL;
+
+	return chan->device->device_prep_slave_sg(chan, &sg, 1,
+						  dir, flags, NULL);
+}
+
+static inline struct dma_async_tx_descriptor *dmaengine_prep_slave_sg(
+	struct dma_chan *chan, struct scatterlist *sgl,	unsigned int sg_len,
+	enum dma_transfer_direction dir, unsigned long flags)
+{
+	if (!chan || !chan->device || !chan->device->device_prep_slave_sg)
+		return NULL;
+
+	return chan->device->device_prep_slave_sg(chan, sgl, sg_len,
+						  dir, flags, NULL);
+}
+
+#ifdef CONFIG_RAPIDIO_DMA_ENGINE
+struct rio_dma_ext;
+static inline struct dma_async_tx_descriptor *dmaengine_prep_rio_sg(
+	struct dma_chan *chan, struct scatterlist *sgl,	unsigned int sg_len,
+	enum dma_transfer_direction dir, unsigned long flags,
+	struct rio_dma_ext *rio_ext)
+{
+	if (!chan || !chan->device || !chan->device->device_prep_slave_sg)
+		return NULL;
+
+	return chan->device->device_prep_slave_sg(chan, sgl, sg_len,
+						  dir, flags, rio_ext);
+}
+#endif
+
+static inline struct dma_async_tx_descriptor *dmaengine_prep_dma_cyclic(
+		struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len,
+		size_t period_len, enum dma_transfer_direction dir,
+		unsigned long flags)
+{
+	if (!chan || !chan->device || !chan->device->device_prep_dma_cyclic)
+		return NULL;
+
+	return chan->device->device_prep_dma_cyclic(chan, buf_addr, buf_len,
+						period_len, dir, flags);
+}
+
+static inline struct dma_async_tx_descriptor *dmaengine_prep_interleaved_dma(
+		struct dma_chan *chan, struct dma_interleaved_template *xt,
+		unsigned long flags)
+{
+	if (!chan || !chan->device || !chan->device->device_prep_interleaved_dma)
+		return NULL;
+
+	return chan->device->device_prep_interleaved_dma(chan, xt, flags);
+}
+
+static inline struct dma_async_tx_descriptor *dmaengine_prep_dma_memset(
+		struct dma_chan *chan, dma_addr_t dest, int value, size_t len,
+		unsigned long flags)
+{
+	if (!chan || !chan->device || !chan->device->device_prep_dma_memset)
+		return NULL;
+
+	return chan->device->device_prep_dma_memset(chan, dest, value,
+						    len, flags);
+}
+
+static inline struct dma_async_tx_descriptor *dmaengine_prep_dma_memcpy(
+		struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
+		size_t len, unsigned long flags)
+{
+	if (!chan || !chan->device || !chan->device->device_prep_dma_memcpy)
+		return NULL;
+
+	return chan->device->device_prep_dma_memcpy(chan, dest, src,
+						    len, flags);
+}
+
+/**
+ * dmaengine_terminate_all() - Terminate all active DMA transfers
+ * @chan: The channel for which to terminate the transfers
+ *
+ * This function is DEPRECATED use either dmaengine_terminate_sync() or
+ * dmaengine_terminate_async() instead.
+ */
+static inline int dmaengine_terminate_all(struct dma_chan *chan)
+{
+	if (chan->device->device_terminate_all)
+		return chan->device->device_terminate_all(chan);
+
+	return -ENOSYS;
+}
+
+/**
+ * dmaengine_terminate_async() - Terminate all active DMA transfers
+ * @chan: The channel for which to terminate the transfers
+ *
+ * Calling this function will terminate all active and pending descriptors
+ * that have previously been submitted to the channel. It is not guaranteed
+ * though that the transfer for the active descriptor has stopped when the
+ * function returns. Furthermore it is possible the complete callback of a
+ * submitted transfer is still running when this function returns.
+ *
+ * dmaengine_synchronize() needs to be called before it is safe to free
+ * any memory that is accessed by previously submitted descriptors or before
+ * freeing any resources accessed from within the completion callback of any
+ * perviously submitted descriptors.
+ *
+ * This function can be called from atomic context as well as from within a
+ * complete callback of a descriptor submitted on the same channel.
+ *
+ * If none of the two conditions above apply consider using
+ * dmaengine_terminate_sync() instead.
+ */
+static inline int dmaengine_terminate_async(struct dma_chan *chan)
+{
+	if (chan->device->device_terminate_all)
+		return chan->device->device_terminate_all(chan);
+
+	return -EINVAL;
+}
+
+/**
+ * dmaengine_synchronize() - Synchronize DMA channel termination
+ * @chan: The channel to synchronize
+ *
+ * Synchronizes to the DMA channel termination to the current context. When this
+ * function returns it is guaranteed that all transfers for previously issued
+ * descriptors have stopped and and it is safe to free the memory assoicated
+ * with them. Furthermore it is guaranteed that all complete callback functions
+ * for a previously submitted descriptor have finished running and it is safe to
+ * free resources accessed from within the complete callbacks.
+ *
+ * The behavior of this function is undefined if dma_async_issue_pending() has
+ * been called between dmaengine_terminate_async() and this function.
+ *
+ * This function must only be called from non-atomic context and must not be
+ * called from within a complete callback of a descriptor submitted on the same
+ * channel.
+ */
+static inline void dmaengine_synchronize(struct dma_chan *chan)
+{
+	might_sleep();
+
+	if (chan->device->device_synchronize)
+		chan->device->device_synchronize(chan);
+}
+
+/**
+ * dmaengine_terminate_sync() - Terminate all active DMA transfers
+ * @chan: The channel for which to terminate the transfers
+ *
+ * Calling this function will terminate all active and pending transfers
+ * that have previously been submitted to the channel. It is similar to
+ * dmaengine_terminate_async() but guarantees that the DMA transfer has actually
+ * stopped and that all complete callbacks have finished running when the
+ * function returns.
+ *
+ * This function must only be called from non-atomic context and must not be
+ * called from within a complete callback of a descriptor submitted on the same
+ * channel.
+ */
+static inline int dmaengine_terminate_sync(struct dma_chan *chan)
+{
+	int ret;
+
+	ret = dmaengine_terminate_async(chan);
+	if (ret)
+		return ret;
+
+	dmaengine_synchronize(chan);
+
+	return 0;
+}
+
+static inline int dmaengine_pause(struct dma_chan *chan)
+{
+	if (chan->device->device_pause)
+		return chan->device->device_pause(chan);
+
+	return -ENOSYS;
+}
+
+static inline int dmaengine_resume(struct dma_chan *chan)
+{
+	if (chan->device->device_resume)
+		return chan->device->device_resume(chan);
+
+	return -ENOSYS;
+}
+
+static inline enum dma_status dmaengine_tx_status(struct dma_chan *chan,
+	dma_cookie_t cookie, struct dma_tx_state *state)
+{
+	return chan->device->device_tx_status(chan, cookie, state);
+}
+
+static inline dma_cookie_t dmaengine_submit(struct dma_async_tx_descriptor *desc)
+{
+	return desc->tx_submit(desc);
+}
+
+static inline bool dmaengine_check_align(enum dmaengine_alignment align,
+					 size_t off1, size_t off2, size_t len)
+{
+	size_t mask;
+
+	if (!align)
+		return true;
+	mask = (1 << align) - 1;
+	if (mask & (off1 | off2 | len))
+		return false;
+	return true;
+}
+
+static inline bool is_dma_copy_aligned(struct dma_device *dev, size_t off1,
+				       size_t off2, size_t len)
+{
+	return dmaengine_check_align(dev->copy_align, off1, off2, len);
+}
+
+static inline bool is_dma_xor_aligned(struct dma_device *dev, size_t off1,
+				      size_t off2, size_t len)
+{
+	return dmaengine_check_align(dev->xor_align, off1, off2, len);
+}
+
+static inline bool is_dma_pq_aligned(struct dma_device *dev, size_t off1,
+				     size_t off2, size_t len)
+{
+	return dmaengine_check_align(dev->pq_align, off1, off2, len);
+}
+
+static inline bool is_dma_fill_aligned(struct dma_device *dev, size_t off1,
+				       size_t off2, size_t len)
+{
+	return dmaengine_check_align(dev->fill_align, off1, off2, len);
+}
+
+static inline void
+dma_set_maxpq(struct dma_device *dma, int maxpq, int has_pq_continue)
+{
+	dma->max_pq = maxpq;
+	if (has_pq_continue)
+		dma->max_pq |= DMA_HAS_PQ_CONTINUE;
+}
+
+static inline bool dmaf_continue(enum dma_ctrl_flags flags)
+{
+	return (flags & DMA_PREP_CONTINUE) == DMA_PREP_CONTINUE;
+}
+
+static inline bool dmaf_p_disabled_continue(enum dma_ctrl_flags flags)
+{
+	enum dma_ctrl_flags mask = DMA_PREP_CONTINUE | DMA_PREP_PQ_DISABLE_P;
+
+	return (flags & mask) == mask;
+}
+
+static inline bool dma_dev_has_pq_continue(struct dma_device *dma)
+{
+	return (dma->max_pq & DMA_HAS_PQ_CONTINUE) == DMA_HAS_PQ_CONTINUE;
+}
+
+static inline unsigned short dma_dev_to_maxpq(struct dma_device *dma)
+{
+	return dma->max_pq & ~DMA_HAS_PQ_CONTINUE;
+}
+
+/* dma_maxpq - reduce maxpq in the face of continued operations
+ * @dma - dma device with PQ capability
+ * @flags - to check if DMA_PREP_CONTINUE and DMA_PREP_PQ_DISABLE_P are set
+ *
+ * When an engine does not support native continuation we need 3 extra
+ * source slots to reuse P and Q with the following coefficients:
+ * 1/ {00} * P : remove P from Q', but use it as a source for P'
+ * 2/ {01} * Q : use Q to continue Q' calculation
+ * 3/ {00} * Q : subtract Q from P' to cancel (2)
+ *
+ * In the case where P is disabled we only need 1 extra source:
+ * 1/ {01} * Q : use Q to continue Q' calculation
+ */
+static inline int dma_maxpq(struct dma_device *dma, enum dma_ctrl_flags flags)
+{
+	if (dma_dev_has_pq_continue(dma) || !dmaf_continue(flags))
+		return dma_dev_to_maxpq(dma);
+	else if (dmaf_p_disabled_continue(flags))
+		return dma_dev_to_maxpq(dma) - 1;
+	else if (dmaf_continue(flags))
+		return dma_dev_to_maxpq(dma) - 3;
+	BUG();
+}
+
+static inline size_t dmaengine_get_icg(bool inc, bool sgl, size_t icg,
+				      size_t dir_icg)
+{
+	if (inc) {
+		if (dir_icg)
+			return dir_icg;
+		else if (sgl)
+			return icg;
+	}
+
+	return 0;
+}
+
+static inline size_t dmaengine_get_dst_icg(struct dma_interleaved_template *xt,
+					   struct data_chunk *chunk)
+{
+	return dmaengine_get_icg(xt->dst_inc, xt->dst_sgl,
+				 chunk->icg, chunk->dst_icg);
+}
+
+static inline size_t dmaengine_get_src_icg(struct dma_interleaved_template *xt,
+					   struct data_chunk *chunk)
+{
+	return dmaengine_get_icg(xt->src_inc, xt->src_sgl,
+				 chunk->icg, chunk->src_icg);
+}
+
+/* --- public DMA engine API --- */
+
+#ifdef CONFIG_DMA_ENGINE
+void dmaengine_get(void);
+void dmaengine_put(void);
+#else
+static inline void dmaengine_get(void)
+{
+}
+static inline void dmaengine_put(void)
+{
+}
+#endif
+
+#ifdef CONFIG_ASYNC_TX_DMA
+#define async_dmaengine_get()	dmaengine_get()
+#define async_dmaengine_put()	dmaengine_put()
+#ifndef CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH
+#define async_dma_find_channel(type) dma_find_channel(DMA_ASYNC_TX)
+#else
+#define async_dma_find_channel(type) dma_find_channel(type)
+#endif /* CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH */
+#else
+static inline void async_dmaengine_get(void)
+{
+}
+static inline void async_dmaengine_put(void)
+{
+}
+static inline struct dma_chan *
+async_dma_find_channel(enum dma_transaction_type type)
+{
+	return NULL;
+}
+#endif /* CONFIG_ASYNC_TX_DMA */
+void dma_async_tx_descriptor_init(struct dma_async_tx_descriptor *tx,
+				  struct dma_chan *chan);
+
+static inline void async_tx_ack(struct dma_async_tx_descriptor *tx)
+{
+	tx->flags |= DMA_CTRL_ACK;
+}
+
+static inline void async_tx_clear_ack(struct dma_async_tx_descriptor *tx)
+{
+	tx->flags &= ~DMA_CTRL_ACK;
+}
+
+static inline bool async_tx_test_ack(struct dma_async_tx_descriptor *tx)
+{
+	return (tx->flags & DMA_CTRL_ACK) == DMA_CTRL_ACK;
+}
+
+#define dma_cap_set(tx, mask) __dma_cap_set((tx), &(mask))
+static inline void
+__dma_cap_set(enum dma_transaction_type tx_type, dma_cap_mask_t *dstp)
+{
+	set_bit(tx_type, dstp->bits);
+}
+
+#define dma_cap_clear(tx, mask) __dma_cap_clear((tx), &(mask))
+static inline void
+__dma_cap_clear(enum dma_transaction_type tx_type, dma_cap_mask_t *dstp)
+{
+	clear_bit(tx_type, dstp->bits);
+}
+
+#define dma_cap_zero(mask) __dma_cap_zero(&(mask))
+static inline void __dma_cap_zero(dma_cap_mask_t *dstp)
+{
+	bitmap_zero(dstp->bits, DMA_TX_TYPE_END);
+}
+
+#define dma_has_cap(tx, mask) __dma_has_cap((tx), &(mask))
+static inline int
+__dma_has_cap(enum dma_transaction_type tx_type, dma_cap_mask_t *srcp)
+{
+	return test_bit(tx_type, srcp->bits);
+}
+
+#define for_each_dma_cap_mask(cap, mask) \
+	for_each_set_bit(cap, mask.bits, DMA_TX_TYPE_END)
+
+/**
+ * dma_async_issue_pending - flush pending transactions to HW
+ * @chan: target DMA channel
+ *
+ * This allows drivers to push copies to HW in batches,
+ * reducing MMIO writes where possible.
+ */
+static inline void dma_async_issue_pending(struct dma_chan *chan)
+{
+	chan->device->device_issue_pending(chan);
+}
+
+/**
+ * dma_async_is_tx_complete - poll for transaction completion
+ * @chan: DMA channel
+ * @cookie: transaction identifier to check status of
+ * @last: returns last completed cookie, can be NULL
+ * @used: returns last issued cookie, can be NULL
+ *
+ * If @last and @used are passed in, upon return they reflect the driver
+ * internal state and can be used with dma_async_is_complete() to check
+ * the status of multiple cookies without re-checking hardware state.
+ */
+static inline enum dma_status dma_async_is_tx_complete(struct dma_chan *chan,
+	dma_cookie_t cookie, dma_cookie_t *last, dma_cookie_t *used)
+{
+	struct dma_tx_state state;
+	enum dma_status status;
+
+	status = chan->device->device_tx_status(chan, cookie, &state);
+	if (last)
+		*last = state.last;
+	if (used)
+		*used = state.used;
+	return status;
+}
+
+/**
+ * dma_async_is_complete - test a cookie against chan state
+ * @cookie: transaction identifier to test status of
+ * @last_complete: last know completed transaction
+ * @last_used: last cookie value handed out
+ *
+ * dma_async_is_complete() is used in dma_async_is_tx_complete()
+ * the test logic is separated for lightweight testing of multiple cookies
+ */
+static inline enum dma_status dma_async_is_complete(dma_cookie_t cookie,
+			dma_cookie_t last_complete, dma_cookie_t last_used)
+{
+	if (last_complete <= last_used) {
+		if ((cookie <= last_complete) || (cookie > last_used))
+			return DMA_COMPLETE;
+	} else {
+		if ((cookie <= last_complete) && (cookie > last_used))
+			return DMA_COMPLETE;
+	}
+	return DMA_IN_PROGRESS;
+}
+
+static inline void
+dma_set_tx_state(struct dma_tx_state *st, dma_cookie_t last, dma_cookie_t used, u32 residue)
+{
+	if (st) {
+		st->last = last;
+		st->used = used;
+		st->residue = residue;
+	}
+}
+
+#ifdef CONFIG_DMA_ENGINE
+struct dma_chan *dma_find_channel(enum dma_transaction_type tx_type);
+enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie);
+enum dma_status dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx);
+void dma_issue_pending_all(void);
+struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
+					dma_filter_fn fn, void *fn_param);
+struct dma_chan *dma_request_slave_channel(struct device *dev, const char *name);
+
+struct dma_chan *dma_request_chan(struct device *dev, const char *name);
+struct dma_chan *dma_request_chan_by_mask(const dma_cap_mask_t *mask);
+
+void dma_release_channel(struct dma_chan *chan);
+int dma_get_slave_caps(struct dma_chan *chan, struct dma_slave_caps *caps);
+#else
+static inline struct dma_chan *dma_find_channel(enum dma_transaction_type tx_type)
+{
+	return NULL;
+}
+static inline enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie)
+{
+	return DMA_COMPLETE;
+}
+static inline enum dma_status dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx)
+{
+	return DMA_COMPLETE;
+}
+static inline void dma_issue_pending_all(void)
+{
+}
+static inline struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
+					      dma_filter_fn fn, void *fn_param)
+{
+	return NULL;
+}
+static inline struct dma_chan *dma_request_slave_channel(struct device *dev,
+							 const char *name)
+{
+	return NULL;
+}
+static inline struct dma_chan *dma_request_chan(struct device *dev,
+						const char *name)
+{
+	return ERR_PTR(-ENODEV);
+}
+static inline struct dma_chan *dma_request_chan_by_mask(
+						const dma_cap_mask_t *mask)
+{
+	return ERR_PTR(-ENODEV);
+}
+static inline void dma_release_channel(struct dma_chan *chan)
+{
+}
+static inline int dma_get_slave_caps(struct dma_chan *chan,
+				     struct dma_slave_caps *caps)
+{
+	return -ENXIO;
+}
+#endif
+
+#define dma_request_slave_channel_reason(dev, name) dma_request_chan(dev, name)
+
+static inline int dmaengine_desc_set_reuse(struct dma_async_tx_descriptor *tx)
+{
+	struct dma_slave_caps caps;
+
+	dma_get_slave_caps(tx->chan, &caps);
+
+	if (caps.descriptor_reuse) {
+		tx->flags |= DMA_CTRL_REUSE;
+		return 0;
+	} else {
+		return -EPERM;
+	}
+}
+
+static inline void dmaengine_desc_clear_reuse(struct dma_async_tx_descriptor *tx)
+{
+	tx->flags &= ~DMA_CTRL_REUSE;
+}
+
+static inline bool dmaengine_desc_test_reuse(struct dma_async_tx_descriptor *tx)
+{
+	return (tx->flags & DMA_CTRL_REUSE) == DMA_CTRL_REUSE;
+}
+
+static inline int dmaengine_desc_free(struct dma_async_tx_descriptor *desc)
+{
+	/* this is supported for reusable desc, so check that */
+	if (dmaengine_desc_test_reuse(desc))
+		return desc->desc_free(desc);
+	else
+		return -EPERM;
+}
+
+/* --- DMA device --- */
+
+int dma_async_device_register(struct dma_device *device);
+int dmaenginem_async_device_register(struct dma_device *device);
+void dma_async_device_unregister(struct dma_device *device);
+void dma_run_dependencies(struct dma_async_tx_descriptor *tx);
+struct dma_chan *dma_get_slave_channel(struct dma_chan *chan);
+struct dma_chan *dma_get_any_slave_channel(struct dma_device *device);
+#define dma_request_channel(mask, x, y) __dma_request_channel(&(mask), x, y)
+#define dma_request_slave_channel_compat(mask, x, y, dev, name) \
+	__dma_request_slave_channel_compat(&(mask), x, y, dev, name)
+
+static inline struct dma_chan
+*__dma_request_slave_channel_compat(const dma_cap_mask_t *mask,
+				  dma_filter_fn fn, void *fn_param,
+				  struct device *dev, const char *name)
+{
+	struct dma_chan *chan;
+
+	chan = dma_request_slave_channel(dev, name);
+	if (chan)
+		return chan;
+
+	if (!fn || !fn_param)
+		return NULL;
+
+	return __dma_request_channel(mask, fn, fn_param);
+}
+#endif /* DMAENGINE_H */