/*
   * DMA Engine test module
   *
   * Copyright (C) 2007 Atmel 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>
  
  static unsigned int test_buf_size = 16384;
  module_param(test_buf_size, uint, S_IRUGO);
  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);
  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);
  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);
  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);

  MODULE_PARM_DESC(max_channels,

  		"Maximum number of channels to use (default: all)");

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

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

  static int timeout = 3000;
  module_param(timeout, uint, S_IRUGO);

  MODULE_PARM_DESC(timeout, "Transfer Timeout in msec (default: 3000), "
  		 "Pass -1 for infinite timeout");

  /*
   * 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
  
  struct dmatest_thread {
  	struct list_head	node;
  	struct task_struct	*task;
  	struct dma_chan		*chan;

  	u8			**srcs;
  	u8			**dsts;
  	enum dma_transaction_type type;

  };
  
  struct dmatest_chan {
  	struct list_head	node;
  	struct dma_chan		*chan;
  	struct list_head	threads;
  };
  
  /*
   * These are protected by dma_list_mutex since they're only used by

   * the DMA filter function callback

   */
  static LIST_HEAD(dmatest_channels);
  static unsigned int nr_channels;
  
  static bool dmatest_match_channel(struct dma_chan *chan)
  {
  	if (test_channel[0] == '\0')
  		return true;

  	return strcmp(dma_chan_name(chan), test_channel) == 0;

  }
  
  static bool dmatest_match_device(struct dma_device *device)
  {
  	if (test_device[0] == '\0')
  		return true;

  	return strcmp(dev_name(device->dev), test_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 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 < test_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 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 < test_buf_size; i++)
  			buf[i] = PATTERN_DST | (~i & PATTERN_COUNT_MASK);
  	}

  }
  
  static void dmatest_mismatch(u8 actual, u8 pattern, unsigned int index,
  		unsigned int counter, bool is_srcbuf)
  {
  	u8		diff = actual ^ pattern;
  	u8		expected = pattern | (~counter & PATTERN_COUNT_MASK);
  	const char	*thread_name = current->comm;
  
  	if (is_srcbuf)
  		pr_warning("%s: srcbuf[0x%x] overwritten!"
  				" Expected %02x, got %02x
  ",
  				thread_name, index, expected, actual);
  	else if ((pattern & PATTERN_COPY)
  			&& (diff & (PATTERN_COPY | PATTERN_OVERWRITE)))
  		pr_warning("%s: dstbuf[0x%x] not copied!"
  				" Expected %02x, got %02x
  ",
  				thread_name, index, expected, actual);
  	else if (diff & PATTERN_SRC)
  		pr_warning("%s: dstbuf[0x%x] was copied!"
  				" Expected %02x, got %02x
  ",
  				thread_name, index, expected, actual);
  	else
  		pr_warning("%s: dstbuf[0x%x] mismatch!"
  				" Expected %02x, got %02x
  ",
  				thread_name, index, expected, actual);
  }

  static unsigned int dmatest_verify(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;
  
  	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 < 32)
  					dmatest_mismatch(actual, pattern, i,
  							 counter, is_srcbuf);
  				error_count++;
  			}
  			counter++;

  		}

  	}
  
  	if (error_count > 32)
  		pr_warning("%s: %u errors suppressed
  ",
  			current->comm, error_count - 32);
  
  	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);

  }

  /*
   * 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 dma_chan		*chan;
  	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[pq_sources + 1];

  	int			ret;

  	int			src_cnt;
  	int			dst_cnt;
  	int			i;

  
  	thread_name = current->comm;

  	set_freezable();

  
  	ret = -ENOMEM;

  
  	smp_rmb();
  	chan = thread->chan;

  	if (thread->type == DMA_MEMCPY)
  		src_cnt = dst_cnt = 1;
  	else if (thread->type == DMA_XOR) {
  		src_cnt = xor_sources | 1; /* force odd to ensure dst = src */
  		dst_cnt = 1;

  	} else if (thread->type == DMA_PQ) {
  		src_cnt = pq_sources | 1; /* force odd to ensure dst = src */
  		dst_cnt = 2;

  		for (i = 0; i < src_cnt; i++)

  			pq_coefs[i] = 1;

  	} else
  		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(test_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(test_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()
  	       && !(iterations && total_tests >= iterations)) {

  		struct dma_device *dev = chan->device;

  		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 > test_buf_size) {
  			pr_err("%u-byte buffer too small for %d-byte alignment
  ",
  			       test_buf_size, 1 << align);
  			break;
  		}
  
  		len = dmatest_random() % test_buf_size + 1;

  		len = (len >> align) << align;

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

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

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

  		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);
  		}

  		/* 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],
  						     test_buf_size,
  						     DMA_BIDIRECTIONAL);
  		}

  		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) {

  			for (i = 0; i < src_cnt; i++)
  				dma_unmap_single(dev->dev, dma_srcs[i], len,
  						 DMA_TO_DEVICE);
  			for (i = 0; i < dst_cnt; i++)
  				dma_unmap_single(dev->dev, dma_dsts[i],
  						 test_buf_size,
  						 DMA_BIDIRECTIONAL);

  			pr_warning("%s: #%u: prep error with src_off=0x%x "
  					"dst_off=0x%x len=0x%x
  ",
  					thread_name, total_tests - 1,
  					src_off, dst_off, len);
  			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)) {
  			pr_warning("%s: #%u: submit error %d with src_off=0x%x "
  					"dst_off=0x%x len=0x%x
  ",
  					thread_name, total_tests - 1, cookie,
  					src_off, dst_off, len);
  			msleep(100);
  			failed_tests++;
  			continue;
  		}

  		dma_async_issue_pending(chan);

  		wait_event_freezable_timeout(done_wait, done.done,
  					     msecs_to_jiffies(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.
  			 */

  			pr_warning("%s: #%u: test timed out
  ",
  				   thread_name, total_tests - 1);
  			failed_tests++;
  			continue;
  		} else if (status != DMA_SUCCESS) {
  			pr_warning("%s: #%u: got completion callback,"
  				   " but status is \'%s\'
  ",
  				   thread_name, total_tests - 1,
  				   status == DMA_ERROR ? "error" : "in progress");

  			failed_tests++;
  			continue;
  		}

  		/* Unmap by myself (see DMA_COMPL_SKIP_DEST_UNMAP above) */

  		for (i = 0; i < dst_cnt; i++)
  			dma_unmap_single(dev->dev, dma_dsts[i], test_buf_size,
  					 DMA_BIDIRECTIONAL);

  
  		error_count = 0;
  
  		pr_debug("%s: verifying source buffer...
  ", thread_name);

  		error_count += dmatest_verify(thread->srcs, 0, src_off,

  				0, PATTERN_SRC, true);

  		error_count += dmatest_verify(thread->srcs, src_off,

  				src_off + len, src_off,
  				PATTERN_SRC | PATTERN_COPY, true);

  		error_count += dmatest_verify(thread->srcs, src_off + len,

  				test_buf_size, src_off + len,
  				PATTERN_SRC, true);
  
  		pr_debug("%s: verifying dest buffer...
  ",
  				thread->task->comm);

  		error_count += dmatest_verify(thread->dsts, 0, dst_off,

  				0, PATTERN_DST, false);

  		error_count += dmatest_verify(thread->dsts, dst_off,

  				dst_off + len, src_off,
  				PATTERN_SRC | PATTERN_COPY, false);

  		error_count += dmatest_verify(thread->dsts, dst_off + len,

  				test_buf_size, dst_off + len,
  				PATTERN_DST, false);
  
  		if (error_count) {
  			pr_warning("%s: #%u: %u errors with "
  				"src_off=0x%x dst_off=0x%x len=0x%x
  ",
  				thread_name, total_tests - 1, error_count,
  				src_off, dst_off, len);
  			failed_tests++;
  		} else {
  			pr_debug("%s: #%u: No errors with "
  				"src_off=0x%x dst_off=0x%x len=0x%x
  ",
  				thread_name, total_tests - 1,
  				src_off, dst_off, len);
  		}
  	}
  
  	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:

  	pr_notice("%s: terminating after %u tests, %u failures (status %d)
  ",
  			thread_name, total_tests, failed_tests, ret);

  	/* terminate all transfers on specified channels */
  	chan->device->device_control(chan, DMA_TERMINATE_ALL, 0);

  	if (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
  ",
  				thread->task->comm, ret);
  		list_del(&thread->node);
  		kfree(thread);
  	}

  
  	/* terminate all transfers on specified channels */
  	dtc->chan->device->device_control(dtc->chan, DMA_TERMINATE_ALL, 0);

  	kfree(dtc);
  }

  static int dmatest_add_threads(struct dmatest_chan *dtc, enum dma_transaction_type type)

  {

  	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 < threads_per_chan; i++) {
  		thread = kzalloc(sizeof(struct dmatest_thread), GFP_KERNEL);
  		if (!thread) {

  			pr_warning("dmatest: No memory for %s-%s%u
  ",
  				   dma_chan_name(chan), op, i);

  			break;
  		}
  		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
  ",
  					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 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
  ", 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(dtc, DMA_MEMCPY);

  		thread_count += cnt > 0 ? cnt : 0;

  	}
  	if (dma_has_cap(DMA_XOR, dma_dev->cap_mask)) {
  		cnt = dmatest_add_threads(dtc, DMA_XOR);

  		thread_count += cnt > 0 ? cnt : 0;

  	}

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

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

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

  	return 0;

  }

  static bool filter(struct dma_chan *chan, void *param)

  {

  	if (!dmatest_match_channel(chan) || !dmatest_match_device(chan->device))

  		return false;

  	else

  		return true;

  }

  static int __init dmatest_init(void)
  {

  	dma_cap_mask_t mask;
  	struct dma_chan *chan;
  	int err = 0;
  
  	dma_cap_zero(mask);
  	dma_cap_set(DMA_MEMCPY, mask);
  	for (;;) {
  		chan = dma_request_channel(mask, filter, NULL);
  		if (chan) {
  			err = dmatest_add_channel(chan);

  			if (err) {

  				dma_release_channel(chan);
  				break; /* add_channel failed, punt */
  			}
  		} else
  			break; /* no more channels available */
  		if (max_channels && nr_channels >= max_channels)
  			break; /* we have all we need */
  	}

  	return err;

  }

  /* when compiled-in wait for drivers to load first */
  late_initcall(dmatest_init);

  
  static void __exit dmatest_exit(void)
  {

  	struct dmatest_chan *dtc, *_dtc;

  	struct dma_chan *chan;

  
  	list_for_each_entry_safe(dtc, _dtc, &dmatest_channels, node) {
  		list_del(&dtc->node);

  		chan = dtc->chan;

  		dmatest_cleanup_channel(dtc);
  		pr_debug("dmatest: dropped channel %s
  ",

  			 dma_chan_name(chan));
  		dma_release_channel(chan);

  	}

  }
  module_exit(dmatest_exit);

  MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");

  MODULE_LICENSE("GPL v2");