/*
 * DMA Engine test module
 *
 * Copyright (C) 2007 Atmel Corporation
 * Copyright (C) 2013 Intel Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/freezer.h>
#include <linux/init.h>
#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/random.h>
#include <linux/slab.h>
#include <linux/wait.h>
#include <linux/ctype.h>
#include <linux/debugfs.h>
#include <linux/uaccess.h>
#include <linux/seq_file.h>

static unsigned int test_buf_size = 16384;
module_param(test_buf_size, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(test_buf_size, "Size of the memcpy test buffer");

static char test_channel[20];
module_param_string(channel, test_channel, sizeof(test_channel),
		S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(channel, "Bus ID of the channel to test (default: any)");

static char test_device[20];
module_param_string(device, test_device, sizeof(test_device),
		S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(device, "Bus ID of the DMA Engine to test (default: any)");

static unsigned int threads_per_chan = 1;
module_param(threads_per_chan, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(threads_per_chan,
		"Number of threads to start per channel (default: 1)");

static unsigned int max_channels;
module_param(max_channels, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(max_channels,
		"Maximum number of channels to use (default: all)");

static unsigned int iterations;
module_param(iterations, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(iterations,
		"Iterations before stopping test (default: infinite)");

static unsigned int xor_sources = 3;
module_param(xor_sources, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(xor_sources,
		"Number of xor source buffers (default: 3)");

static unsigned int pq_sources = 3;
module_param(pq_sources, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(pq_sources,
		"Number of p+q source buffers (default: 3)");

static int timeout = 3000;
module_param(timeout, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(timeout, "Transfer Timeout in msec (default: 3000), "
		 "Pass -1 for infinite timeout");

/* Maximum amount of mismatched bytes in buffer to print */
#define MAX_ERROR_COUNT		32

/*
 * Initialization patterns. All bytes in the source buffer has bit 7
 * set, all bytes in the destination buffer has bit 7 cleared.
 *
 * Bit 6 is set for all bytes which are to be copied by the DMA
 * engine. Bit 5 is set for all bytes which are to be overwritten by
 * the DMA engine.
 *
 * The remaining bits are the inverse of a counter which increments by
 * one for each byte address.
 */
#define PATTERN_SRC		0x80
#define PATTERN_DST		0x00
#define PATTERN_COPY		0x40
#define PATTERN_OVERWRITE	0x20
#define PATTERN_COUNT_MASK	0x1f

enum dmatest_error_type {
	DMATEST_ET_OK,
	DMATEST_ET_MAP_SRC,
	DMATEST_ET_MAP_DST,
	DMATEST_ET_PREP,
	DMATEST_ET_SUBMIT,
	DMATEST_ET_TIMEOUT,
	DMATEST_ET_DMA_ERROR,
	DMATEST_ET_DMA_IN_PROGRESS,
	DMATEST_ET_VERIFY,
	DMATEST_ET_VERIFY_BUF,
};

struct dmatest_verify_buffer {
	unsigned int	index;
	u8		expected;
	u8		actual;
};

struct dmatest_verify_result {
	unsigned int			error_count;
	struct dmatest_verify_buffer	data[MAX_ERROR_COUNT];
	u8				pattern;
	bool				is_srcbuf;
};

struct dmatest_thread_result {
	struct list_head	node;
	unsigned int		n;
	unsigned int		src_off;
	unsigned int		dst_off;
	unsigned int		len;
	enum dmatest_error_type	type;
	union {
		unsigned long			data;
		dma_cookie_t			cookie;
		enum dma_status			status;
		int				error;
		struct dmatest_verify_result	*vr;
	};
};

struct dmatest_result {
	struct list_head	node;
	char			*name;
	struct list_head	results;
};

struct dmatest_info;

struct dmatest_thread {
	struct list_head	node;
	struct dmatest_info	*info;
	struct task_struct	*task;
	struct dma_chan		*chan;
	u8			**srcs;
	u8			**dsts;
	enum dma_transaction_type type;
	bool			done;
};

struct dmatest_chan {
	struct list_head	node;
	struct dma_chan		*chan;
	struct list_head	threads;
};

/**
 * struct dmatest_params - test parameters.
 * @buf_size:		size of the memcpy test buffer
 * @channel:		bus ID of the channel to test
 * @device:		bus ID of the DMA Engine to test
 * @threads_per_chan:	number of threads to start per channel
 * @max_channels:	maximum number of channels to use
 * @iterations:		iterations before stopping test
 * @xor_sources:	number of xor source buffers
 * @pq_sources:		number of p+q source buffers
 * @timeout:		transfer timeout in msec, -1 for infinite timeout
 */
struct dmatest_params {
	unsigned int	buf_size;
	char		channel[20];
	char		device[20];
	unsigned int	threads_per_chan;
	unsigned int	max_channels;
	unsigned int	iterations;
	unsigned int	xor_sources;
	unsigned int	pq_sources;
	int		timeout;
};

/**
 * struct dmatest_info - test information.
 * @params:		test parameters
 * @lock:		access protection to the fields of this structure
 */
struct dmatest_info {
	/* Test parameters */
	struct dmatest_params	params;

	/* Internal state */
	struct list_head	channels;
	unsigned int		nr_channels;
	struct mutex		lock;

	/* debugfs related stuff */
	struct dentry		*root;

	/* Test results */
	struct list_head	results;
	struct mutex		results_lock;
};

static struct dmatest_info test_info;

static bool dmatest_match_channel(struct dmatest_params *params,
		struct dma_chan *chan)
{
	if (params->channel[0] == '\0')
		return true;
	return strcmp(dma_chan_name(chan), params->channel) == 0;
}

static bool dmatest_match_device(struct dmatest_params *params,
		struct dma_device *device)
{
	if (params->device[0] == '\0')
		return true;
	return strcmp(dev_name(device->dev), params->device) == 0;
}

static unsigned long dmatest_random(void)
{
	unsigned long buf;

	get_random_bytes(&buf, sizeof(buf));
	return buf;
}

static void dmatest_init_srcs(u8 **bufs, unsigned int start, unsigned int len,
		unsigned int buf_size)
{
	unsigned int i;
	u8 *buf;

	for (; (buf = *bufs); bufs++) {
		for (i = 0; i < start; i++)
			buf[i] = PATTERN_SRC | (~i & PATTERN_COUNT_MASK);
		for ( ; i < start + len; i++)
			buf[i] = PATTERN_SRC | PATTERN_COPY
				| (~i & PATTERN_COUNT_MASK);
		for ( ; i < buf_size; i++)
			buf[i] = PATTERN_SRC | (~i & PATTERN_COUNT_MASK);
		buf++;
	}
}

static void dmatest_init_dsts(u8 **bufs, unsigned int start, unsigned int len,
		unsigned int buf_size)
{
	unsigned int i;
	u8 *buf;

	for (; (buf = *bufs); bufs++) {
		for (i = 0; i < start; i++)
			buf[i] = PATTERN_DST | (~i & PATTERN_COUNT_MASK);
		for ( ; i < start + len; i++)
			buf[i] = PATTERN_DST | PATTERN_OVERWRITE
				| (~i & PATTERN_COUNT_MASK);
		for ( ; i < buf_size; i++)
			buf[i] = PATTERN_DST | (~i & PATTERN_COUNT_MASK);
	}
}

static unsigned int dmatest_verify(struct dmatest_verify_result *vr, u8 **bufs,
		unsigned int start, unsigned int end, unsigned int counter,
		u8 pattern, bool is_srcbuf)
{
	unsigned int i;
	unsigned int error_count = 0;
	u8 actual;
	u8 expected;
	u8 *buf;
	unsigned int counter_orig = counter;
	struct dmatest_verify_buffer *vb;

	for (; (buf = *bufs); bufs++) {
		counter = counter_orig;
		for (i = start; i < end; i++) {
			actual = buf[i];
			expected = pattern | (~counter & PATTERN_COUNT_MASK);
			if (actual != expected) {
				if (error_count < MAX_ERROR_COUNT && vr) {
					vb = &vr->data[error_count];
					vb->index = i;
					vb->expected = expected;
					vb->actual = actual;
				}
				error_count++;
			}
			counter++;
		}
	}

	if (error_count > MAX_ERROR_COUNT)
		pr_warning("%s: %u errors suppressed\n",
			current->comm, error_count - MAX_ERROR_COUNT);

	return error_count;
}

/* poor man's completion - we want to use wait_event_freezable() on it */
struct dmatest_done {
	bool			done;
	wait_queue_head_t	*wait;
};

static void dmatest_callback(void *arg)
{
	struct dmatest_done *done = arg;

	done->done = true;
	wake_up_all(done->wait);
}

static inline void unmap_src(struct device *dev, dma_addr_t *addr, size_t len,
			     unsigned int count)
{
	while (count--)
		dma_unmap_single(dev, addr[count], len, DMA_TO_DEVICE);
}

static inline void unmap_dst(struct device *dev, dma_addr_t *addr, size_t len,
			     unsigned int count)
{
	while (count--)
		dma_unmap_single(dev, addr[count], len, DMA_BIDIRECTIONAL);
}

static unsigned int min_odd(unsigned int x, unsigned int y)
{
	unsigned int val = min(x, y);

	return val % 2 ? val : val - 1;
}

static char *verify_result_get_one(struct dmatest_verify_result *vr,
		unsigned int i)
{
	struct dmatest_verify_buffer *vb = &vr->data[i];
	u8 diff = vb->actual ^ vr->pattern;
	static char buf[512];
	char *msg;

	if (vr->is_srcbuf)
		msg = "srcbuf overwritten!";
	else if ((vr->pattern & PATTERN_COPY)
			&& (diff & (PATTERN_COPY | PATTERN_OVERWRITE)))
		msg = "dstbuf not copied!";
	else if (diff & PATTERN_SRC)
		msg = "dstbuf was copied!";
	else
		msg = "dstbuf mismatch!";

	snprintf(buf, sizeof(buf) - 1, "%s [0x%x] Expected %02x, got %02x", msg,
		 vb->index, vb->expected, vb->actual);

	return buf;
}

static char *thread_result_get(const char *name,
		struct dmatest_thread_result *tr)
{
	static const char * const messages[] = {
		[DMATEST_ET_OK]			= "No errors",
		[DMATEST_ET_MAP_SRC]		= "src mapping error",
		[DMATEST_ET_MAP_DST]		= "dst mapping error",
		[DMATEST_ET_PREP]		= "prep error",
		[DMATEST_ET_SUBMIT]		= "submit error",
		[DMATEST_ET_TIMEOUT]		= "test timed out",
		[DMATEST_ET_DMA_ERROR]		=
			"got completion callback (DMA_ERROR)",
		[DMATEST_ET_DMA_IN_PROGRESS]	=
			"got completion callback (DMA_IN_PROGRESS)",
		[DMATEST_ET_VERIFY]		= "errors",
		[DMATEST_ET_VERIFY_BUF]		= "verify errors",
	};
	static char buf[512];

	snprintf(buf, sizeof(buf) - 1,
		 "%s: #%u: %s with src_off=0x%x ""dst_off=0x%x len=0x%x (%lu)",
		 name, tr->n, messages[tr->type], tr->src_off, tr->dst_off,
		 tr->len, tr->data);

	return buf;
}

static int thread_result_add(struct dmatest_info *info,
		struct dmatest_result *r, enum dmatest_error_type type,
		unsigned int n, unsigned int src_off, unsigned int dst_off,
		unsigned int len, unsigned long data)
{
	struct dmatest_thread_result *tr;

	tr = kzalloc(sizeof(*tr), GFP_KERNEL);
	if (!tr)
		return -ENOMEM;

	tr->type = type;
	tr->n = n;
	tr->src_off = src_off;
	tr->dst_off = dst_off;
	tr->len = len;
	tr->data = data;

	mutex_lock(&info->results_lock);
	list_add_tail(&tr->node, &r->results);
	mutex_unlock(&info->results_lock);

	if (tr->type == DMATEST_ET_OK)
		pr_debug("%s\n", thread_result_get(r->name, tr));
	else
		pr_warn("%s\n", thread_result_get(r->name, tr));

	return 0;
}

static unsigned int verify_result_add(struct dmatest_info *info,
		struct dmatest_result *r, unsigned int n,
		unsigned int src_off, unsigned int dst_off, unsigned int len,
		u8 **bufs, int whence, unsigned int counter, u8 pattern,
		bool is_srcbuf)
{
	struct dmatest_verify_result *vr;
	unsigned int error_count;
	unsigned int buf_off = is_srcbuf ? src_off : dst_off;
	unsigned int start, end;

	if (whence < 0) {
		start = 0;
		end = buf_off;
	} else if (whence > 0) {
		start = buf_off + len;
		end = info->params.buf_size;
	} else {
		start = buf_off;
		end = buf_off + len;
	}

	vr = kmalloc(sizeof(*vr), GFP_KERNEL);
	if (!vr) {
		pr_warn("dmatest: No memory to store verify result\n");
		return dmatest_verify(NULL, bufs, start, end, counter, pattern,
				      is_srcbuf);
	}

	vr->pattern = pattern;
	vr->is_srcbuf = is_srcbuf;

	error_count = dmatest_verify(vr, bufs, start, end, counter, pattern,
				     is_srcbuf);
	if (error_count) {
		vr->error_count = error_count;
		thread_result_add(info, r, DMATEST_ET_VERIFY_BUF, n, src_off,
				  dst_off, len, (unsigned long)vr);
		return error_count;
	}

	kfree(vr);
	return 0;
}

static void result_free(struct dmatest_info *info, const char *name)
{
	struct dmatest_result *r, *_r;

	mutex_lock(&info->results_lock);
	list_for_each_entry_safe(r, _r, &info->results, node) {
		struct dmatest_thread_result *tr, *_tr;

		if (name && strcmp(r->name, name))
			continue;

		list_for_each_entry_safe(tr, _tr, &r->results, node) {
			if (tr->type == DMATEST_ET_VERIFY_BUF)
				kfree(tr->vr);
			list_del(&tr->node);
			kfree(tr);
		}

		kfree(r->name);
		list_del(&r->node);
		kfree(r);
	}

	mutex_unlock(&info->results_lock);
}

static struct dmatest_result *result_init(struct dmatest_info *info,
		const char *name)
{
	struct dmatest_result *r;

	r = kzalloc(sizeof(*r), GFP_KERNEL);
	if (r) {
		r->name = kstrdup(name, GFP_KERNEL);
		INIT_LIST_HEAD(&r->results);
		mutex_lock(&info->results_lock);
		list_add_tail(&r->node, &info->results);
		mutex_unlock(&info->results_lock);
	}
	return r;
}

/*
 * This function repeatedly tests DMA transfers of various lengths and
 * offsets for a given operation type until it is told to exit by
 * kthread_stop(). There may be multiple threads running this function
 * in parallel for a single channel, and there may be multiple channels
 * being tested in parallel.
 *
 * Before each test, the source and destination buffer is initialized
 * with a known pattern. This pattern is different depending on
 * whether it's in an area which is supposed to be copied or
 * overwritten, and different in the source and destination buffers.
 * So if the DMA engine doesn't copy exactly what we tell it to copy,
 * we'll notice.
 */
static int dmatest_func(void *data)
{
	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(done_wait);
	struct dmatest_thread	*thread = data;
	struct dmatest_done	done = { .wait = &done_wait };
	struct dmatest_info	*info;
	struct dmatest_params	*params;
	struct dma_chan		*chan;
	struct dma_device	*dev;
	const char		*thread_name;
	unsigned int		src_off, dst_off, len;
	unsigned int		error_count;
	unsigned int		failed_tests = 0;
	unsigned int		total_tests = 0;
	dma_cookie_t		cookie;
	enum dma_status		status;
	enum dma_ctrl_flags 	flags;
	u8			*pq_coefs = NULL;
	int			ret;
	int			src_cnt;
	int			dst_cnt;
	int			i;
	struct dmatest_result	*result;

	thread_name = current->comm;
	set_freezable();

	ret = -ENOMEM;

	smp_rmb();
	info = thread->info;
	params = &info->params;
	chan = thread->chan;
	dev = chan->device;
	if (thread->type == DMA_MEMCPY)
		src_cnt = dst_cnt = 1;
	else if (thread->type == DMA_XOR) {
		/* force odd to ensure dst = src */
		src_cnt = min_odd(params->xor_sources | 1, dev->max_xor);
		dst_cnt = 1;
	} else if (thread->type == DMA_PQ) {
		/* force odd to ensure dst = src */
		src_cnt = min_odd(params->pq_sources | 1, dma_maxpq(dev, 0));
		dst_cnt = 2;

		pq_coefs = kmalloc(params->pq_sources+1, GFP_KERNEL);
		if (!pq_coefs)
			goto err_thread_type;

		for (i = 0; i < src_cnt; i++)
			pq_coefs[i] = 1;
	} else
		goto err_thread_type;

	result = result_init(info, thread_name);
	if (!result)
		goto err_srcs;

	thread->srcs = kcalloc(src_cnt+1, sizeof(u8 *), GFP_KERNEL);
	if (!thread->srcs)
		goto err_srcs;
	for (i = 0; i < src_cnt; i++) {
		thread->srcs[i] = kmalloc(params->buf_size, GFP_KERNEL);
		if (!thread->srcs[i])
			goto err_srcbuf;
	}
	thread->srcs[i] = NULL;

	thread->dsts = kcalloc(dst_cnt+1, sizeof(u8 *), GFP_KERNEL);
	if (!thread->dsts)
		goto err_dsts;
	for (i = 0; i < dst_cnt; i++) {
		thread->dsts[i] = kmalloc(params->buf_size, GFP_KERNEL);
		if (!thread->dsts[i])
			goto err_dstbuf;
	}
	thread->dsts[i] = NULL;

	set_user_nice(current, 10);

	/*
	 * src buffers are freed by the DMAEngine code with dma_unmap_single()
	 * dst buffers are freed by ourselves below
	 */
	flags = DMA_CTRL_ACK | DMA_PREP_INTERRUPT
	      | DMA_COMPL_SKIP_DEST_UNMAP | DMA_COMPL_SRC_UNMAP_SINGLE;

	while (!kthread_should_stop()
	       && !(params->iterations && total_tests >= params->iterations)) {
		struct dma_async_tx_descriptor *tx = NULL;
		dma_addr_t dma_srcs[src_cnt];
		dma_addr_t dma_dsts[dst_cnt];
		u8 align = 0;

		total_tests++;

		/* honor alignment restrictions */
		if (thread->type == DMA_MEMCPY)
			align = dev->copy_align;
		else if (thread->type == DMA_XOR)
			align = dev->xor_align;
		else if (thread->type == DMA_PQ)
			align = dev->pq_align;

		if (1 << align > params->buf_size) {
			pr_err("%u-byte buffer too small for %d-byte alignment\n",
			       params->buf_size, 1 << align);
			break;
		}

		len = dmatest_random() % params->buf_size + 1;
		len = (len >> align) << align;
		if (!len)
			len = 1 << align;
		src_off = dmatest_random() % (params->buf_size - len + 1);
		dst_off = dmatest_random() % (params->buf_size - len + 1);

		src_off = (src_off >> align) << align;
		dst_off = (dst_off >> align) << align;

		dmatest_init_srcs(thread->srcs, src_off, len, params->buf_size);
		dmatest_init_dsts(thread->dsts, dst_off, len, params->buf_size);

		for (i = 0; i < src_cnt; i++) {
			u8 *buf = thread->srcs[i] + src_off;

			dma_srcs[i] = dma_map_single(dev->dev, buf, len,
						     DMA_TO_DEVICE);
			ret = dma_mapping_error(dev->dev, dma_srcs[i]);
			if (ret) {
				unmap_src(dev->dev, dma_srcs, len, i);
				thread_result_add(info, result,
						  DMATEST_ET_MAP_SRC,
						  total_tests, src_off, dst_off,
						  len, ret);
				failed_tests++;
				continue;
			}
		}
		/* map with DMA_BIDIRECTIONAL to force writeback/invalidate */
		for (i = 0; i < dst_cnt; i++) {
			dma_dsts[i] = dma_map_single(dev->dev, thread->dsts[i],
						     params->buf_size,
						     DMA_BIDIRECTIONAL);
			ret = dma_mapping_error(dev->dev, dma_dsts[i]);
			if (ret) {
				unmap_src(dev->dev, dma_srcs, len, src_cnt);
				unmap_dst(dev->dev, dma_dsts, params->buf_size,
					  i);
				thread_result_add(info, result,
						  DMATEST_ET_MAP_DST,
						  total_tests, src_off, dst_off,
						  len, ret);
				failed_tests++;
				continue;
			}
		}

		if (thread->type == DMA_MEMCPY)
			tx = dev->device_prep_dma_memcpy(chan,
							 dma_dsts[0] + dst_off,
							 dma_srcs[0], len,
							 flags);
		else if (thread->type == DMA_XOR)
			tx = dev->device_prep_dma_xor(chan,
						      dma_dsts[0] + dst_off,
						      dma_srcs, src_cnt,
						      len, flags);
		else if (thread->type == DMA_PQ) {
			dma_addr_t dma_pq[dst_cnt];

			for (i = 0; i < dst_cnt; i++)
				dma_pq[i] = dma_dsts[i] + dst_off;
			tx = dev->device_prep_dma_pq(chan, dma_pq, dma_srcs,
						     src_cnt, pq_coefs,
						     len, flags);
		}

		if (!tx) {
			unmap_src(dev->dev, dma_srcs, len, src_cnt);
			unmap_dst(dev->dev, dma_dsts, params->buf_size,
				  dst_cnt);
			thread_result_add(info, result, DMATEST_ET_PREP,
					  total_tests, src_off, dst_off,
					  len, 0);
			msleep(100);
			failed_tests++;
			continue;
		}

		done.done = false;
		tx->callback = dmatest_callback;
		tx->callback_param = &done;
		cookie = tx->tx_submit(tx);

		if (dma_submit_error(cookie)) {
			thread_result_add(info, result, DMATEST_ET_SUBMIT,
					  total_tests, src_off, dst_off,
					  len, cookie);
			msleep(100);
			failed_tests++;
			continue;
		}
		dma_async_issue_pending(chan);

		wait_event_freezable_timeout(done_wait, done.done,
					     msecs_to_jiffies(params->timeout));

		status = dma_async_is_tx_complete(chan, cookie, NULL, NULL);

		if (!done.done) {
			/*
			 * We're leaving the timed out dma operation with
			 * dangling pointer to done_wait.  To make this
			 * correct, we'll need to allocate wait_done for
			 * each test iteration and perform "who's gonna
			 * free it this time?" dancing.  For now, just
			 * leave it dangling.
			 */
			thread_result_add(info, result, DMATEST_ET_TIMEOUT,
					  total_tests, src_off, dst_off,
					  len, 0);
			failed_tests++;
			continue;
		} else if (status != DMA_SUCCESS) {
			enum dmatest_error_type type = (status == DMA_ERROR) ?
				DMATEST_ET_DMA_ERROR : DMATEST_ET_DMA_IN_PROGRESS;
			thread_result_add(info, result, type,
					  total_tests, src_off, dst_off,
					  len, status);
			failed_tests++;
			continue;
		}

		/* Unmap by myself (see DMA_COMPL_SKIP_DEST_UNMAP above) */
		unmap_dst(dev->dev, dma_dsts, params->buf_size, dst_cnt);

		error_count = 0;

		pr_debug("%s: verifying source buffer...\n", thread_name);
		error_count += verify_result_add(info, result, total_tests,
				src_off, dst_off, len, thread->srcs, -1,
				0, PATTERN_SRC, true);
		error_count += verify_result_add(info, result, total_tests,
				src_off, dst_off, len, thread->srcs, 0,
				src_off, PATTERN_SRC | PATTERN_COPY, true);
		error_count += verify_result_add(info, result, total_tests,
				src_off, dst_off, len, thread->srcs, 1,
				src_off + len, PATTERN_SRC, true);

		pr_debug("%s: verifying dest buffer...\n", thread_name);
		error_count += verify_result_add(info, result, total_tests,
				src_off, dst_off, len, thread->dsts, -1,
				0, PATTERN_DST, false);
		error_count += verify_result_add(info, result, total_tests,
				src_off, dst_off, len, thread->dsts, 0,
				src_off, PATTERN_SRC | PATTERN_COPY, false);
		error_count += verify_result_add(info, result, total_tests,
				src_off, dst_off, len, thread->dsts, 1,
				dst_off + len, PATTERN_DST, false);

		if (error_count) {
			thread_result_add(info, result, DMATEST_ET_VERIFY,
					  total_tests, src_off, dst_off,
					  len, error_count);
			failed_tests++;
		} else {
			thread_result_add(info, result, DMATEST_ET_OK,
					  total_tests, src_off, dst_off,
					  len, 0);
		}
	}

	ret = 0;
	for (i = 0; thread->dsts[i]; i++)
		kfree(thread->dsts[i]);
err_dstbuf:
	kfree(thread->dsts);
err_dsts:
	for (i = 0; thread->srcs[i]; i++)
		kfree(thread->srcs[i]);
err_srcbuf:
	kfree(thread->srcs);
err_srcs:
	kfree(pq_coefs);
err_thread_type:
	pr_notice("%s: terminating after %u tests, %u failures (status %d)\n",
			thread_name, total_tests, failed_tests, ret);

	/* terminate all transfers on specified channels */
	if (ret)
		dmaengine_terminate_all(chan);

	thread->done = true;

	if (params->iterations > 0)
		while (!kthread_should_stop()) {
			DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wait_dmatest_exit);
			interruptible_sleep_on(&wait_dmatest_exit);
		}

	return ret;
}

static void dmatest_cleanup_channel(struct dmatest_chan *dtc)
{
	struct dmatest_thread	*thread;
	struct dmatest_thread	*_thread;
	int			ret;

	list_for_each_entry_safe(thread, _thread, &dtc->threads, node) {
		ret = kthread_stop(thread->task);
		pr_debug("dmatest: thread %s exited with status %d\n",
				thread->task->comm, ret);
		list_del(&thread->node);
		kfree(thread);
	}

	/* terminate all transfers on specified channels */
	dmaengine_terminate_all(dtc->chan);

	kfree(dtc);
}

static int dmatest_add_threads(struct dmatest_info *info,
		struct dmatest_chan *dtc, enum dma_transaction_type type)
{
	struct dmatest_params *params = &info->params;
	struct dmatest_thread *thread;
	struct dma_chan *chan = dtc->chan;
	char *op;
	unsigned int i;

	if (type == DMA_MEMCPY)
		op = "copy";
	else if (type == DMA_XOR)
		op = "xor";
	else if (type == DMA_PQ)
		op = "pq";
	else
		return -EINVAL;

	for (i = 0; i < params->threads_per_chan; i++) {
		thread = kzalloc(sizeof(struct dmatest_thread), GFP_KERNEL);
		if (!thread) {
			pr_warning("dmatest: No memory for %s-%s%u\n",
				   dma_chan_name(chan), op, i);

			break;
		}
		thread->info = info;
		thread->chan = dtc->chan;
		thread->type = type;
		smp_wmb();
		thread->task = kthread_run(dmatest_func, thread, "%s-%s%u",
				dma_chan_name(chan), op, i);
		if (IS_ERR(thread->task)) {
			pr_warning("dmatest: Failed to run thread %s-%s%u\n",
					dma_chan_name(chan), op, i);
			kfree(thread);
			break;
		}

		/* srcbuf and dstbuf are allocated by the thread itself */

		list_add_tail(&thread->node, &dtc->threads);
	}

	return i;
}

static int dmatest_add_channel(struct dmatest_info *info,
		struct dma_chan *chan)
{
	struct dmatest_chan	*dtc;
	struct dma_device	*dma_dev = chan->device;
	unsigned int		thread_count = 0;
	int cnt;

	dtc = kmalloc(sizeof(struct dmatest_chan), GFP_KERNEL);
	if (!dtc) {
		pr_warning("dmatest: No memory for %s\n", dma_chan_name(chan));
		return -ENOMEM;
	}

	dtc->chan = chan;
	INIT_LIST_HEAD(&dtc->threads);

	if (dma_has_cap(DMA_MEMCPY, dma_dev->cap_mask)) {
		cnt = dmatest_add_threads(info, dtc, DMA_MEMCPY);
		thread_count += cnt > 0 ? cnt : 0;
	}
	if (dma_has_cap(DMA_XOR, dma_dev->cap_mask)) {
		cnt = dmatest_add_threads(info, dtc, DMA_XOR);
		thread_count += cnt > 0 ? cnt : 0;
	}
	if (dma_has_cap(DMA_PQ, dma_dev->cap_mask)) {
		cnt = dmatest_add_threads(info, dtc, DMA_PQ);
		thread_count += cnt > 0 ? cnt : 0;
	}

	pr_info("dmatest: Started %u threads using %s\n",
		thread_count, dma_chan_name(chan));

	list_add_tail(&dtc->node, &info->channels);
	info->nr_channels++;

	return 0;
}

static bool filter(struct dma_chan *chan, void *param)
{
	struct dmatest_params *params = param;

	if (!dmatest_match_channel(params, chan) ||
	    !dmatest_match_device(params, chan->device))
		return false;
	else
		return true;
}

static int __run_threaded_test(struct dmatest_info *info)
{
	dma_cap_mask_t mask;
	struct dma_chan *chan;
	struct dmatest_params *params = &info->params;
	int err = 0;

	dma_cap_zero(mask);
	dma_cap_set(DMA_MEMCPY, mask);
	for (;;) {
		chan = dma_request_channel(mask, filter, params);
		if (chan) {
			err = dmatest_add_channel(info, chan);
			if (err) {
				dma_release_channel(chan);
				break; /* add_channel failed, punt */
			}
		} else
			break; /* no more channels available */
		if (params->max_channels &&
		    info->nr_channels >= params->max_channels)
			break; /* we have all we need */
	}
	return err;
}

#ifndef MODULE
static int run_threaded_test(struct dmatest_info *info)
{
	int ret;

	mutex_lock(&info->lock);
	ret = __run_threaded_test(info);
	mutex_unlock(&info->lock);
	return ret;
}
#endif

static void __stop_threaded_test(struct dmatest_info *info)
{
	struct dmatest_chan *dtc, *_dtc;
	struct dma_chan *chan;

	list_for_each_entry_safe(dtc, _dtc, &info->channels, node) {
		list_del(&dtc->node);
		chan = dtc->chan;
		dmatest_cleanup_channel(dtc);
		pr_debug("dmatest: dropped channel %s\n", dma_chan_name(chan));
		dma_release_channel(chan);
	}

	info->nr_channels = 0;
}

static void stop_threaded_test(struct dmatest_info *info)
{
	mutex_lock(&info->lock);
	__stop_threaded_test(info);
	mutex_unlock(&info->lock);
}

static int __restart_threaded_test(struct dmatest_info *info, bool run)
{
	struct dmatest_params *params = &info->params;

	/* Stop any running test first */
	__stop_threaded_test(info);

	if (run == false)
		return 0;

	/* Clear results from previous run */
	result_free(info, NULL);

	/* Copy test parameters */
	params->buf_size = test_buf_size;
	strlcpy(params->channel, strim(test_channel), sizeof(params->channel));
	strlcpy(params->device, strim(test_device), sizeof(params->device));
	params->threads_per_chan = threads_per_chan;
	params->max_channels = max_channels;
	params->iterations = iterations;
	params->xor_sources = xor_sources;
	params->pq_sources = pq_sources;
	params->timeout = timeout;

	/* Run test with new parameters */
	return __run_threaded_test(info);
}

static bool __is_threaded_test_run(struct dmatest_info *info)
{
	struct dmatest_chan *dtc;

	list_for_each_entry(dtc, &info->channels, node) {
		struct dmatest_thread *thread;

		list_for_each_entry(thread, &dtc->threads, node) {
			if (!thread->done)
				return true;
		}
	}

	return false;
}

static ssize_t dtf_read_run(struct file *file, char __user *user_buf,
		size_t count, loff_t *ppos)
{
	struct dmatest_info *info = file->private_data;
	char buf[3];

	mutex_lock(&info->lock);

	if (__is_threaded_test_run(info)) {
		buf[0] = 'Y';
	} else {
		__stop_threaded_test(info);
		buf[0] = 'N';
	}

	mutex_unlock(&info->lock);
	buf[1] = '\n';
	buf[2] = 0x00;
	return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
}

static ssize_t dtf_write_run(struct file *file, const char __user *user_buf,
		size_t count, loff_t *ppos)
{
	struct dmatest_info *info = file->private_data;
	char buf[16];
	bool bv;
	int ret = 0;

	if (copy_from_user(buf, user_buf, min(count, (sizeof(buf) - 1))))
		return -EFAULT;

	if (strtobool(buf, &bv) == 0) {
		mutex_lock(&info->lock);

		if (__is_threaded_test_run(info))
			ret = -EBUSY;
		else
			ret = __restart_threaded_test(info, bv);

		mutex_unlock(&info->lock);
	}

	return ret ? ret : count;
}

static const struct file_operations dtf_run_fops = {
	.read	= dtf_read_run,
	.write	= dtf_write_run,
	.open	= simple_open,
	.llseek	= default_llseek,
};

static int dtf_results_show(struct seq_file *sf, void *data)
{
	struct dmatest_info *info = sf->private;
	struct dmatest_result *result;
	struct dmatest_thread_result *tr;
	unsigned int i;

	mutex_lock(&info->results_lock);
	list_for_each_entry(result, &info->results, node) {
		list_for_each_entry(tr, &result->results, node) {
			seq_printf(sf, "%s\n",
				thread_result_get(result->name, tr));
			if (tr->type == DMATEST_ET_VERIFY_BUF) {
				for (i = 0; i < tr->vr->error_count; i++) {
					seq_printf(sf, "\t%s\n",
						verify_result_get_one(tr->vr, i));
				}
			}
		}
	}

	mutex_unlock(&info->results_lock);
	return 0;
}

static int dtf_results_open(struct inode *inode, struct file *file)
{
	return single_open(file, dtf_results_show, inode->i_private);
}

static const struct file_operations dtf_results_fops = {
	.open		= dtf_results_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};

static int dmatest_register_dbgfs(struct dmatest_info *info)
{
	struct dentry *d;

	d = debugfs_create_dir("dmatest", NULL);
	if (IS_ERR(d))
		return PTR_ERR(d);
	if (!d)
		goto err_root;

	info->root = d;

	/* Run or stop threaded test */
	debugfs_create_file("run", S_IWUSR | S_IRUGO, info->root, info,
			    &dtf_run_fops);

	/* Results of test in progress */
	debugfs_create_file("results", S_IRUGO, info->root, info,
			    &dtf_results_fops);

	return 0;

err_root:
	pr_err("dmatest: Failed to initialize debugfs\n");
	return -ENOMEM;
}

static int __init dmatest_init(void)
{
	struct dmatest_info *info = &test_info;
	int ret;

	memset(info, 0, sizeof(*info));

	mutex_init(&info->lock);
	INIT_LIST_HEAD(&info->channels);

	mutex_init(&info->results_lock);
	INIT_LIST_HEAD(&info->results);

	ret = dmatest_register_dbgfs(info);
	if (ret)
		return ret;

#ifdef MODULE
	return 0;
#else
	return run_threaded_test(info);
#endif
}
/* when compiled-in wait for drivers to load first */
late_initcall(dmatest_init);

static void __exit dmatest_exit(void)
{
	struct dmatest_info *info = &test_info;

	debugfs_remove_recursive(info->root);
	stop_threaded_test(info);
	result_free(info, NULL);
}
module_exit(dmatest_exit);

MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
MODULE_LICENSE("GPL v2");