/*
   * offload engine driver for the Intel Xscale series of i/o processors
   * Copyright © 2006, Intel Corporation.
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms and conditions of the GNU General Public License,
   * version 2, as published by the Free Software Foundation.
   *
   * This program is distributed in the hope 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.
   *
   * You should have received a copy of the GNU General Public License along with
   * this program; if not, write to the Free Software Foundation, Inc.,
   * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
   *
   */
  
  /*
   * This driver supports the asynchrounous DMA copy and RAID engines available
   * on the Intel Xscale(R) family of I/O Processors (IOP 32x, 33x, 134x)
   */
  
  #include <linux/init.h>
  #include <linux/module.h>

  #include <linux/delay.h>
  #include <linux/dma-mapping.h>
  #include <linux/spinlock.h>
  #include <linux/interrupt.h>
  #include <linux/platform_device.h>
  #include <linux/memory.h>
  #include <linux/ioport.h>

  #include <linux/raid/pq.h>

  #include <linux/slab.h>

  #include <mach/adma.h>

  
  #define to_iop_adma_chan(chan) container_of(chan, struct iop_adma_chan, common)
  #define to_iop_adma_device(dev) \
  	container_of(dev, struct iop_adma_device, common)
  #define tx_to_iop_adma_slot(tx) \
  	container_of(tx, struct iop_adma_desc_slot, async_tx)
  
  /**
   * iop_adma_free_slots - flags descriptor slots for reuse
   * @slot: Slot to free
   * Caller must hold &iop_chan->lock while calling this function
   */
  static void iop_adma_free_slots(struct iop_adma_desc_slot *slot)
  {
  	int stride = slot->slots_per_op;
  
  	while (stride--) {
  		slot->slots_per_op = 0;
  		slot = list_entry(slot->slot_node.next,
  				struct iop_adma_desc_slot,
  				slot_node);
  	}
  }

  static void
  iop_desc_unmap(struct iop_adma_chan *iop_chan, struct iop_adma_desc_slot *desc)
  {
  	struct dma_async_tx_descriptor *tx = &desc->async_tx;
  	struct iop_adma_desc_slot *unmap = desc->group_head;
  	struct device *dev = &iop_chan->device->pdev->dev;
  	u32 len = unmap->unmap_len;
  	enum dma_ctrl_flags flags = tx->flags;
  	u32 src_cnt;
  	dma_addr_t addr;
  	dma_addr_t dest;
  
  	src_cnt = unmap->unmap_src_cnt;
  	dest = iop_desc_get_dest_addr(unmap, iop_chan);
  	if (!(flags & DMA_COMPL_SKIP_DEST_UNMAP)) {
  		enum dma_data_direction dir;
  
  		if (src_cnt > 1) /* is xor? */
  			dir = DMA_BIDIRECTIONAL;
  		else
  			dir = DMA_FROM_DEVICE;
  
  		dma_unmap_page(dev, dest, len, dir);
  	}
  
  	if (!(flags & DMA_COMPL_SKIP_SRC_UNMAP)) {
  		while (src_cnt--) {
  			addr = iop_desc_get_src_addr(unmap, iop_chan, src_cnt);
  			if (addr == dest)
  				continue;
  			dma_unmap_page(dev, addr, len, DMA_TO_DEVICE);
  		}
  	}
  	desc->group_head = NULL;
  }
  
  static void
  iop_desc_unmap_pq(struct iop_adma_chan *iop_chan, struct iop_adma_desc_slot *desc)
  {
  	struct dma_async_tx_descriptor *tx = &desc->async_tx;
  	struct iop_adma_desc_slot *unmap = desc->group_head;
  	struct device *dev = &iop_chan->device->pdev->dev;
  	u32 len = unmap->unmap_len;
  	enum dma_ctrl_flags flags = tx->flags;
  	u32 src_cnt = unmap->unmap_src_cnt;
  	dma_addr_t pdest = iop_desc_get_dest_addr(unmap, iop_chan);
  	dma_addr_t qdest = iop_desc_get_qdest_addr(unmap, iop_chan);
  	int i;
  
  	if (tx->flags & DMA_PREP_CONTINUE)
  		src_cnt -= 3;
  
  	if (!(flags & DMA_COMPL_SKIP_DEST_UNMAP) && !desc->pq_check_result) {
  		dma_unmap_page(dev, pdest, len, DMA_BIDIRECTIONAL);
  		dma_unmap_page(dev, qdest, len, DMA_BIDIRECTIONAL);
  	}
  
  	if (!(flags & DMA_COMPL_SKIP_SRC_UNMAP)) {
  		dma_addr_t addr;
  
  		for (i = 0; i < src_cnt; i++) {
  			addr = iop_desc_get_src_addr(unmap, iop_chan, i);
  			dma_unmap_page(dev, addr, len, DMA_TO_DEVICE);
  		}
  		if (desc->pq_check_result) {
  			dma_unmap_page(dev, pdest, len, DMA_TO_DEVICE);
  			dma_unmap_page(dev, qdest, len, DMA_TO_DEVICE);
  		}
  	}
  
  	desc->group_head = NULL;
  }

  static dma_cookie_t
  iop_adma_run_tx_complete_actions(struct iop_adma_desc_slot *desc,
  	struct iop_adma_chan *iop_chan, dma_cookie_t cookie)
  {

  	struct dma_async_tx_descriptor *tx = &desc->async_tx;
  
  	BUG_ON(tx->cookie < 0);
  	if (tx->cookie > 0) {
  		cookie = tx->cookie;
  		tx->cookie = 0;

  
  		/* call the callback (must not sleep or submit new
  		 * operations to this channel)
  		 */

  		if (tx->callback)
  			tx->callback(tx->callback_param);

  
  		/* unmap dma addresses
  		 * (unmap_single vs unmap_page?)
  		 */
  		if (desc->group_head && desc->unmap_len) {

  			if (iop_desc_is_pq(desc))
  				iop_desc_unmap_pq(iop_chan, desc);
  			else
  				iop_desc_unmap(iop_chan, desc);

  		}
  	}
  
  	/* run dependent operations */

  	dma_run_dependencies(tx);

  
  	return cookie;
  }
  
  static int
  iop_adma_clean_slot(struct iop_adma_desc_slot *desc,
  	struct iop_adma_chan *iop_chan)
  {
  	/* the client is allowed to attach dependent operations
  	 * until 'ack' is set
  	 */

  	if (!async_tx_test_ack(&desc->async_tx))

  		return 0;
  
  	/* leave the last descriptor in the chain
  	 * so we can append to it
  	 */
  	if (desc->chain_node.next == &iop_chan->chain)
  		return 1;
  
  	dev_dbg(iop_chan->device->common.dev,
  		"\tfree slot: %d slots_per_op: %d
  ",
  		desc->idx, desc->slots_per_op);
  
  	list_del(&desc->chain_node);
  	iop_adma_free_slots(desc);
  
  	return 0;
  }
  
  static void __iop_adma_slot_cleanup(struct iop_adma_chan *iop_chan)
  {
  	struct iop_adma_desc_slot *iter, *_iter, *grp_start = NULL;
  	dma_cookie_t cookie = 0;
  	u32 current_desc = iop_chan_get_current_descriptor(iop_chan);
  	int busy = iop_chan_is_busy(iop_chan);
  	int seen_current = 0, slot_cnt = 0, slots_per_op = 0;

  	dev_dbg(iop_chan->device->common.dev, "%s
  ", __func__);

  	/* free completed slots from the chain starting with
  	 * the oldest descriptor
  	 */
  	list_for_each_entry_safe(iter, _iter, &iop_chan->chain,
  					chain_node) {
  		pr_debug("\tcookie: %d slot: %d busy: %d "
  			"this_desc: %#x next_desc: %#x ack: %d
  ",
  			iter->async_tx.cookie, iter->idx, busy,
  			iter->async_tx.phys, iop_desc_get_next_desc(iter),

  			async_tx_test_ack(&iter->async_tx));

  		prefetch(_iter);
  		prefetch(&_iter->async_tx);
  
  		/* do not advance past the current descriptor loaded into the
  		 * hardware channel, subsequent descriptors are either in
  		 * process or have not been submitted
  		 */
  		if (seen_current)
  			break;
  
  		/* stop the search if we reach the current descriptor and the
  		 * channel is busy, or if it appears that the current descriptor
  		 * needs to be re-read (i.e. has been appended to)
  		 */
  		if (iter->async_tx.phys == current_desc) {
  			BUG_ON(seen_current++);
  			if (busy || iop_desc_get_next_desc(iter))
  				break;
  		}
  
  		/* detect the start of a group transaction */
  		if (!slot_cnt && !slots_per_op) {
  			slot_cnt = iter->slot_cnt;
  			slots_per_op = iter->slots_per_op;
  			if (slot_cnt <= slots_per_op) {
  				slot_cnt = 0;
  				slots_per_op = 0;
  			}
  		}
  
  		if (slot_cnt) {
  			pr_debug("\tgroup++
  ");
  			if (!grp_start)
  				grp_start = iter;
  			slot_cnt -= slots_per_op;
  		}
  
  		/* all the members of a group are complete */
  		if (slots_per_op != 0 && slot_cnt == 0) {
  			struct iop_adma_desc_slot *grp_iter, *_grp_iter;
  			int end_of_chain = 0;
  			pr_debug("\tgroup end
  ");
  
  			/* collect the total results */
  			if (grp_start->xor_check_result) {
  				u32 zero_sum_result = 0;
  				slot_cnt = grp_start->slot_cnt;
  				grp_iter = grp_start;
  
  				list_for_each_entry_from(grp_iter,
  					&iop_chan->chain, chain_node) {
  					zero_sum_result |=
  					    iop_desc_get_zero_result(grp_iter);
  					    pr_debug("\titer%d result: %d
  ",
  					    grp_iter->idx, zero_sum_result);
  					slot_cnt -= slots_per_op;
  					if (slot_cnt == 0)
  						break;
  				}
  				pr_debug("\tgrp_start->xor_check_result: %p
  ",
  					grp_start->xor_check_result);
  				*grp_start->xor_check_result = zero_sum_result;
  			}
  
  			/* clean up the group */
  			slot_cnt = grp_start->slot_cnt;
  			grp_iter = grp_start;
  			list_for_each_entry_safe_from(grp_iter, _grp_iter,
  				&iop_chan->chain, chain_node) {
  				cookie = iop_adma_run_tx_complete_actions(
  					grp_iter, iop_chan, cookie);
  
  				slot_cnt -= slots_per_op;
  				end_of_chain = iop_adma_clean_slot(grp_iter,
  					iop_chan);
  
  				if (slot_cnt == 0 || end_of_chain)
  					break;
  			}
  
  			/* the group should be complete at this point */
  			BUG_ON(slot_cnt);
  
  			slots_per_op = 0;
  			grp_start = NULL;
  			if (end_of_chain)
  				break;
  			else
  				continue;
  		} else if (slots_per_op) /* wait for group completion */
  			continue;
  
  		/* write back zero sum results (single descriptor case) */
  		if (iter->xor_check_result && iter->async_tx.cookie)
  			*iter->xor_check_result =
  				iop_desc_get_zero_result(iter);
  
  		cookie = iop_adma_run_tx_complete_actions(
  					iter, iop_chan, cookie);
  
  		if (iop_adma_clean_slot(iter, iop_chan))
  			break;
  	}

  	if (cookie > 0) {
  		iop_chan->completed_cookie = cookie;
  		pr_debug("\tcompleted cookie %d
  ", cookie);
  	}
  }
  
  static void
  iop_adma_slot_cleanup(struct iop_adma_chan *iop_chan)
  {
  	spin_lock_bh(&iop_chan->lock);
  	__iop_adma_slot_cleanup(iop_chan);
  	spin_unlock_bh(&iop_chan->lock);
  }
  
  static void iop_adma_tasklet(unsigned long data)
  {

  	struct iop_adma_chan *iop_chan = (struct iop_adma_chan *) data;

  	/* lockdep will flag depedency submissions as potentially
  	 * recursive locking, this is not the case as a dependency
  	 * submission will never recurse a channels submit routine.
  	 * There are checks in async_tx.c to prevent this.
  	 */
  	spin_lock_nested(&iop_chan->lock, SINGLE_DEPTH_NESTING);

  	__iop_adma_slot_cleanup(iop_chan);
  	spin_unlock(&iop_chan->lock);

  }
  
  static struct iop_adma_desc_slot *
  iop_adma_alloc_slots(struct iop_adma_chan *iop_chan, int num_slots,
  			int slots_per_op)
  {
  	struct iop_adma_desc_slot *iter, *_iter, *alloc_start = NULL;

  	LIST_HEAD(chain);

  	int slots_found, retry = 0;
  
  	/* start search from the last allocated descrtiptor
  	 * if a contiguous allocation can not be found start searching
  	 * from the beginning of the list
  	 */
  retry:
  	slots_found = 0;
  	if (retry == 0)
  		iter = iop_chan->last_used;
  	else
  		iter = list_entry(&iop_chan->all_slots,
  			struct iop_adma_desc_slot,
  			slot_node);
  
  	list_for_each_entry_safe_continue(
  		iter, _iter, &iop_chan->all_slots, slot_node) {
  		prefetch(_iter);
  		prefetch(&_iter->async_tx);
  		if (iter->slots_per_op) {
  			/* give up after finding the first busy slot
  			 * on the second pass through the list
  			 */
  			if (retry)
  				break;
  
  			slots_found = 0;
  			continue;
  		}
  
  		/* start the allocation if the slot is correctly aligned */
  		if (!slots_found++) {
  			if (iop_desc_is_aligned(iter, slots_per_op))
  				alloc_start = iter;
  			else {
  				slots_found = 0;
  				continue;
  			}
  		}
  
  		if (slots_found == num_slots) {
  			struct iop_adma_desc_slot *alloc_tail = NULL;
  			struct iop_adma_desc_slot *last_used = NULL;
  			iter = alloc_start;
  			while (num_slots) {
  				int i;
  				dev_dbg(iop_chan->device->common.dev,
  					"allocated slot: %d "
  					"(desc %p phys: %#x) slots_per_op %d
  ",
  					iter->idx, iter->hw_desc,
  					iter->async_tx.phys, slots_per_op);
  
  				/* pre-ack all but the last descriptor */
  				if (num_slots != slots_per_op)

  					async_tx_ack(&iter->async_tx);

  
  				list_add_tail(&iter->chain_node, &chain);
  				alloc_tail = iter;
  				iter->async_tx.cookie = 0;
  				iter->slot_cnt = num_slots;
  				iter->xor_check_result = NULL;
  				for (i = 0; i < slots_per_op; i++) {
  					iter->slots_per_op = slots_per_op - i;
  					last_used = iter;
  					iter = list_entry(iter->slot_node.next,
  						struct iop_adma_desc_slot,
  						slot_node);
  				}
  				num_slots -= slots_per_op;
  			}
  			alloc_tail->group_head = alloc_start;
  			alloc_tail->async_tx.cookie = -EBUSY;

  			list_splice(&chain, &alloc_tail->tx_list);

  			iop_chan->last_used = last_used;
  			iop_desc_clear_next_desc(alloc_start);
  			iop_desc_clear_next_desc(alloc_tail);
  			return alloc_tail;
  		}
  	}
  	if (!retry++)
  		goto retry;

  	/* perform direct reclaim if the allocation fails */
  	__iop_adma_slot_cleanup(iop_chan);

  
  	return NULL;
  }
  
  static dma_cookie_t
  iop_desc_assign_cookie(struct iop_adma_chan *iop_chan,
  	struct iop_adma_desc_slot *desc)
  {
  	dma_cookie_t cookie = iop_chan->common.cookie;
  	cookie++;
  	if (cookie < 0)
  		cookie = 1;
  	iop_chan->common.cookie = desc->async_tx.cookie = cookie;
  	return cookie;
  }
  
  static void iop_adma_check_threshold(struct iop_adma_chan *iop_chan)
  {
  	dev_dbg(iop_chan->device->common.dev, "pending: %d
  ",
  		iop_chan->pending);
  
  	if (iop_chan->pending >= IOP_ADMA_THRESHOLD) {
  		iop_chan->pending = 0;
  		iop_chan_append(iop_chan);
  	}
  }
  
  static dma_cookie_t
  iop_adma_tx_submit(struct dma_async_tx_descriptor *tx)
  {
  	struct iop_adma_desc_slot *sw_desc = tx_to_iop_adma_slot(tx);
  	struct iop_adma_chan *iop_chan = to_iop_adma_chan(tx->chan);
  	struct iop_adma_desc_slot *grp_start, *old_chain_tail;
  	int slot_cnt;
  	int slots_per_op;
  	dma_cookie_t cookie;

  	dma_addr_t next_dma;

  
  	grp_start = sw_desc->group_head;
  	slot_cnt = grp_start->slot_cnt;
  	slots_per_op = grp_start->slots_per_op;
  
  	spin_lock_bh(&iop_chan->lock);
  	cookie = iop_desc_assign_cookie(iop_chan, sw_desc);
  
  	old_chain_tail = list_entry(iop_chan->chain.prev,
  		struct iop_adma_desc_slot, chain_node);

  	list_splice_init(&sw_desc->tx_list,

  			 &old_chain_tail->chain_node);
  
  	/* fix up the hardware chain */

  	next_dma = grp_start->async_tx.phys;
  	iop_desc_set_next_desc(old_chain_tail, next_dma);
  	BUG_ON(iop_desc_get_next_desc(old_chain_tail) != next_dma); /* flush */

  	/* check for pre-chained descriptors */

  	iop_paranoia(iop_desc_get_next_desc(sw_desc));

  
  	/* increment the pending count by the number of slots
  	 * memcpy operations have a 1:1 (slot:operation) relation
  	 * other operations are heavier and will pop the threshold
  	 * more often.
  	 */
  	iop_chan->pending += slot_cnt;
  	iop_adma_check_threshold(iop_chan);
  	spin_unlock_bh(&iop_chan->lock);
  
  	dev_dbg(iop_chan->device->common.dev, "%s cookie: %d slot: %d
  ",

  		__func__, sw_desc->async_tx.cookie, sw_desc->idx);

  
  	return cookie;
  }

  static void iop_chan_start_null_memcpy(struct iop_adma_chan *iop_chan);
  static void iop_chan_start_null_xor(struct iop_adma_chan *iop_chan);

  /**
   * iop_adma_alloc_chan_resources -  returns the number of allocated descriptors
   * @chan - allocate descriptor resources for this channel
   * @client - current client requesting the channel be ready for requests
   *
   * Note: We keep the slots for 1 operation on iop_chan->chain at all times.  To
   * avoid deadlock, via async_xor, num_descs_in_pool must at a minimum be
   * greater than 2x the number slots needed to satisfy a device->max_xor
   * request.
   * */

  static int iop_adma_alloc_chan_resources(struct dma_chan *chan)

  {
  	char *hw_desc;
  	int idx;
  	struct iop_adma_chan *iop_chan = to_iop_adma_chan(chan);
  	struct iop_adma_desc_slot *slot = NULL;
  	int init = iop_chan->slots_allocated ? 0 : 1;
  	struct iop_adma_platform_data *plat_data =
  		iop_chan->device->pdev->dev.platform_data;
  	int num_descs_in_pool = plat_data->pool_size/IOP_ADMA_SLOT_SIZE;
  
  	/* Allocate descriptor slots */
  	do {
  		idx = iop_chan->slots_allocated;
  		if (idx == num_descs_in_pool)
  			break;
  
  		slot = kzalloc(sizeof(*slot), GFP_KERNEL);
  		if (!slot) {
  			printk(KERN_INFO "IOP ADMA Channel only initialized"
  				" %d descriptor slots", idx);
  			break;
  		}
  		hw_desc = (char *) iop_chan->device->dma_desc_pool_virt;
  		slot->hw_desc = (void *) &hw_desc[idx * IOP_ADMA_SLOT_SIZE];
  
  		dma_async_tx_descriptor_init(&slot->async_tx, chan);
  		slot->async_tx.tx_submit = iop_adma_tx_submit;

  		INIT_LIST_HEAD(&slot->tx_list);

  		INIT_LIST_HEAD(&slot->chain_node);
  		INIT_LIST_HEAD(&slot->slot_node);

  		hw_desc = (char *) iop_chan->device->dma_desc_pool;
  		slot->async_tx.phys =
  			(dma_addr_t) &hw_desc[idx * IOP_ADMA_SLOT_SIZE];
  		slot->idx = idx;
  
  		spin_lock_bh(&iop_chan->lock);
  		iop_chan->slots_allocated++;
  		list_add_tail(&slot->slot_node, &iop_chan->all_slots);
  		spin_unlock_bh(&iop_chan->lock);
  	} while (iop_chan->slots_allocated < num_descs_in_pool);
  
  	if (idx && !iop_chan->last_used)
  		iop_chan->last_used = list_entry(iop_chan->all_slots.next,
  					struct iop_adma_desc_slot,
  					slot_node);
  
  	dev_dbg(iop_chan->device->common.dev,
  		"allocated %d descriptor slots last_used: %p
  ",
  		iop_chan->slots_allocated, iop_chan->last_used);
  
  	/* initialize the channel and the chain with a null operation */
  	if (init) {
  		if (dma_has_cap(DMA_MEMCPY,
  			iop_chan->device->common.cap_mask))
  			iop_chan_start_null_memcpy(iop_chan);
  		else if (dma_has_cap(DMA_XOR,
  			iop_chan->device->common.cap_mask))
  			iop_chan_start_null_xor(iop_chan);
  		else
  			BUG();
  	}
  
  	return (idx > 0) ? idx : -ENOMEM;
  }
  
  static struct dma_async_tx_descriptor *

  iop_adma_prep_dma_interrupt(struct dma_chan *chan, unsigned long flags)

  {
  	struct iop_adma_chan *iop_chan = to_iop_adma_chan(chan);
  	struct iop_adma_desc_slot *sw_desc, *grp_start;
  	int slot_cnt, slots_per_op;

  	dev_dbg(iop_chan->device->common.dev, "%s
  ", __func__);

  
  	spin_lock_bh(&iop_chan->lock);
  	slot_cnt = iop_chan_interrupt_slot_count(&slots_per_op, iop_chan);
  	sw_desc = iop_adma_alloc_slots(iop_chan, slot_cnt, slots_per_op);
  	if (sw_desc) {
  		grp_start = sw_desc->group_head;
  		iop_desc_init_interrupt(grp_start, iop_chan);
  		grp_start->unmap_len = 0;

  		sw_desc->async_tx.flags = flags;

  	}
  	spin_unlock_bh(&iop_chan->lock);
  
  	return sw_desc ? &sw_desc->async_tx : NULL;
  }

  static struct dma_async_tx_descriptor *

  iop_adma_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dma_dest,

  			 dma_addr_t dma_src, size_t len, unsigned long flags)

  {
  	struct iop_adma_chan *iop_chan = to_iop_adma_chan(chan);
  	struct iop_adma_desc_slot *sw_desc, *grp_start;
  	int slot_cnt, slots_per_op;
  
  	if (unlikely(!len))
  		return NULL;

  	BUG_ON(len > IOP_ADMA_MAX_BYTE_COUNT);

  
  	dev_dbg(iop_chan->device->common.dev, "%s len: %u
  ",

  		__func__, len);

  
  	spin_lock_bh(&iop_chan->lock);
  	slot_cnt = iop_chan_memcpy_slot_count(len, &slots_per_op);
  	sw_desc = iop_adma_alloc_slots(iop_chan, slot_cnt, slots_per_op);
  	if (sw_desc) {
  		grp_start = sw_desc->group_head;

  		iop_desc_init_memcpy(grp_start, flags);

  		iop_desc_set_byte_count(grp_start, iop_chan, len);

  		iop_desc_set_dest_addr(grp_start, iop_chan, dma_dest);
  		iop_desc_set_memcpy_src_addr(grp_start, dma_src);

  		sw_desc->unmap_src_cnt = 1;
  		sw_desc->unmap_len = len;

  		sw_desc->async_tx.flags = flags;

  	}
  	spin_unlock_bh(&iop_chan->lock);
  
  	return sw_desc ? &sw_desc->async_tx : NULL;
  }
  
  static struct dma_async_tx_descriptor *

  iop_adma_prep_dma_memset(struct dma_chan *chan, dma_addr_t dma_dest,

  			 int value, size_t len, unsigned long flags)

  {
  	struct iop_adma_chan *iop_chan = to_iop_adma_chan(chan);
  	struct iop_adma_desc_slot *sw_desc, *grp_start;
  	int slot_cnt, slots_per_op;
  
  	if (unlikely(!len))
  		return NULL;

  	BUG_ON(len > IOP_ADMA_MAX_BYTE_COUNT);

  
  	dev_dbg(iop_chan->device->common.dev, "%s len: %u
  ",

  		__func__, len);

  
  	spin_lock_bh(&iop_chan->lock);
  	slot_cnt = iop_chan_memset_slot_count(len, &slots_per_op);
  	sw_desc = iop_adma_alloc_slots(iop_chan, slot_cnt, slots_per_op);
  	if (sw_desc) {
  		grp_start = sw_desc->group_head;

  		iop_desc_init_memset(grp_start, flags);

  		iop_desc_set_byte_count(grp_start, iop_chan, len);
  		iop_desc_set_block_fill_val(grp_start, value);

  		iop_desc_set_dest_addr(grp_start, iop_chan, dma_dest);

  		sw_desc->unmap_src_cnt = 1;
  		sw_desc->unmap_len = len;

  		sw_desc->async_tx.flags = flags;

  	}
  	spin_unlock_bh(&iop_chan->lock);
  
  	return sw_desc ? &sw_desc->async_tx : NULL;
  }

  static struct dma_async_tx_descriptor *

  iop_adma_prep_dma_xor(struct dma_chan *chan, dma_addr_t dma_dest,
  		      dma_addr_t *dma_src, unsigned int src_cnt, size_t len,

  		      unsigned long flags)

  {
  	struct iop_adma_chan *iop_chan = to_iop_adma_chan(chan);
  	struct iop_adma_desc_slot *sw_desc, *grp_start;
  	int slot_cnt, slots_per_op;
  
  	if (unlikely(!len))
  		return NULL;

  	BUG_ON(len > IOP_ADMA_XOR_MAX_BYTE_COUNT);

  
  	dev_dbg(iop_chan->device->common.dev,

  		"%s src_cnt: %d len: %u flags: %lx
  ",

  		__func__, src_cnt, len, flags);

  
  	spin_lock_bh(&iop_chan->lock);
  	slot_cnt = iop_chan_xor_slot_count(len, src_cnt, &slots_per_op);
  	sw_desc = iop_adma_alloc_slots(iop_chan, slot_cnt, slots_per_op);
  	if (sw_desc) {
  		grp_start = sw_desc->group_head;

  		iop_desc_init_xor(grp_start, src_cnt, flags);

  		iop_desc_set_byte_count(grp_start, iop_chan, len);

  		iop_desc_set_dest_addr(grp_start, iop_chan, dma_dest);

  		sw_desc->unmap_src_cnt = src_cnt;
  		sw_desc->unmap_len = len;

  		sw_desc->async_tx.flags = flags;

  		while (src_cnt--)
  			iop_desc_set_xor_src_addr(grp_start, src_cnt,
  						  dma_src[src_cnt]);

  	}
  	spin_unlock_bh(&iop_chan->lock);
  
  	return sw_desc ? &sw_desc->async_tx : NULL;
  }

  static struct dma_async_tx_descriptor *

  iop_adma_prep_dma_xor_val(struct dma_chan *chan, dma_addr_t *dma_src,
  			  unsigned int src_cnt, size_t len, u32 *result,
  			  unsigned long flags)

  {
  	struct iop_adma_chan *iop_chan = to_iop_adma_chan(chan);
  	struct iop_adma_desc_slot *sw_desc, *grp_start;
  	int slot_cnt, slots_per_op;
  
  	if (unlikely(!len))
  		return NULL;
  
  	dev_dbg(iop_chan->device->common.dev, "%s src_cnt: %d len: %u
  ",

  		__func__, src_cnt, len);

  
  	spin_lock_bh(&iop_chan->lock);
  	slot_cnt = iop_chan_zero_sum_slot_count(len, src_cnt, &slots_per_op);
  	sw_desc = iop_adma_alloc_slots(iop_chan, slot_cnt, slots_per_op);
  	if (sw_desc) {
  		grp_start = sw_desc->group_head;

  		iop_desc_init_zero_sum(grp_start, src_cnt, flags);

  		iop_desc_set_zero_sum_byte_count(grp_start, len);
  		grp_start->xor_check_result = result;
  		pr_debug("\t%s: grp_start->xor_check_result: %p
  ",

  			__func__, grp_start->xor_check_result);

  		sw_desc->unmap_src_cnt = src_cnt;
  		sw_desc->unmap_len = len;

  		sw_desc->async_tx.flags = flags;

  		while (src_cnt--)
  			iop_desc_set_zero_sum_src_addr(grp_start, src_cnt,
  						       dma_src[src_cnt]);

  	}
  	spin_unlock_bh(&iop_chan->lock);
  
  	return sw_desc ? &sw_desc->async_tx : NULL;
  }

  static struct dma_async_tx_descriptor *
  iop_adma_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 iop_adma_chan *iop_chan = to_iop_adma_chan(chan);
  	struct iop_adma_desc_slot *sw_desc, *g;
  	int slot_cnt, slots_per_op;
  	int continue_srcs;
  
  	if (unlikely(!len))
  		return NULL;
  	BUG_ON(len > IOP_ADMA_XOR_MAX_BYTE_COUNT);
  
  	dev_dbg(iop_chan->device->common.dev,
  		"%s src_cnt: %d len: %u flags: %lx
  ",
  		__func__, src_cnt, len, flags);
  
  	if (dmaf_p_disabled_continue(flags))
  		continue_srcs = 1+src_cnt;
  	else if (dmaf_continue(flags))
  		continue_srcs = 3+src_cnt;
  	else
  		continue_srcs = 0+src_cnt;
  
  	spin_lock_bh(&iop_chan->lock);
  	slot_cnt = iop_chan_pq_slot_count(len, continue_srcs, &slots_per_op);
  	sw_desc = iop_adma_alloc_slots(iop_chan, slot_cnt, slots_per_op);
  	if (sw_desc) {
  		int i;
  
  		g = sw_desc->group_head;
  		iop_desc_set_byte_count(g, iop_chan, len);
  
  		/* even if P is disabled its destination address (bits
  		 * [3:0]) must match Q.  It is ok if P points to an
  		 * invalid address, it won't be written.
  		 */
  		if (flags & DMA_PREP_PQ_DISABLE_P)
  			dst[0] = dst[1] & 0x7;
  
  		iop_desc_set_pq_addr(g, dst);
  		sw_desc->unmap_src_cnt = src_cnt;
  		sw_desc->unmap_len = len;
  		sw_desc->async_tx.flags = flags;
  		for (i = 0; i < src_cnt; i++)
  			iop_desc_set_pq_src_addr(g, i, src[i], scf[i]);
  
  		/* if we are continuing a previous operation factor in
  		 * the old p and q values, see the comment for dma_maxpq
  		 * in include/linux/dmaengine.h
  		 */
  		if (dmaf_p_disabled_continue(flags))
  			iop_desc_set_pq_src_addr(g, i++, dst[1], 1);
  		else if (dmaf_continue(flags)) {
  			iop_desc_set_pq_src_addr(g, i++, dst[0], 0);
  			iop_desc_set_pq_src_addr(g, i++, dst[1], 1);
  			iop_desc_set_pq_src_addr(g, i++, dst[1], 0);
  		}
  		iop_desc_init_pq(g, i, flags);
  	}
  	spin_unlock_bh(&iop_chan->lock);
  
  	return sw_desc ? &sw_desc->async_tx : NULL;
  }
  
  static struct dma_async_tx_descriptor *
  iop_adma_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 iop_adma_chan *iop_chan = to_iop_adma_chan(chan);
  	struct iop_adma_desc_slot *sw_desc, *g;
  	int slot_cnt, slots_per_op;
  
  	if (unlikely(!len))
  		return NULL;
  	BUG_ON(len > IOP_ADMA_XOR_MAX_BYTE_COUNT);
  
  	dev_dbg(iop_chan->device->common.dev, "%s src_cnt: %d len: %u
  ",
  		__func__, src_cnt, len);
  
  	spin_lock_bh(&iop_chan->lock);
  	slot_cnt = iop_chan_pq_zero_sum_slot_count(len, src_cnt + 2, &slots_per_op);
  	sw_desc = iop_adma_alloc_slots(iop_chan, slot_cnt, slots_per_op);
  	if (sw_desc) {
  		/* for validate operations p and q are tagged onto the
  		 * end of the source list
  		 */
  		int pq_idx = src_cnt;
  
  		g = sw_desc->group_head;
  		iop_desc_init_pq_zero_sum(g, src_cnt+2, flags);
  		iop_desc_set_pq_zero_sum_byte_count(g, len);
  		g->pq_check_result = pqres;
  		pr_debug("\t%s: g->pq_check_result: %p
  ",
  			__func__, g->pq_check_result);
  		sw_desc->unmap_src_cnt = src_cnt+2;
  		sw_desc->unmap_len = len;
  		sw_desc->async_tx.flags = flags;
  		while (src_cnt--)
  			iop_desc_set_pq_zero_sum_src_addr(g, src_cnt,
  							  src[src_cnt],
  							  scf[src_cnt]);
  		iop_desc_set_pq_zero_sum_addr(g, pq_idx, src);
  	}
  	spin_unlock_bh(&iop_chan->lock);
  
  	return sw_desc ? &sw_desc->async_tx : NULL;
  }

  static void iop_adma_free_chan_resources(struct dma_chan *chan)
  {
  	struct iop_adma_chan *iop_chan = to_iop_adma_chan(chan);
  	struct iop_adma_desc_slot *iter, *_iter;
  	int in_use_descs = 0;
  
  	iop_adma_slot_cleanup(iop_chan);
  
  	spin_lock_bh(&iop_chan->lock);
  	list_for_each_entry_safe(iter, _iter, &iop_chan->chain,
  					chain_node) {
  		in_use_descs++;
  		list_del(&iter->chain_node);
  	}
  	list_for_each_entry_safe_reverse(
  		iter, _iter, &iop_chan->all_slots, slot_node) {
  		list_del(&iter->slot_node);
  		kfree(iter);
  		iop_chan->slots_allocated--;
  	}
  	iop_chan->last_used = NULL;
  
  	dev_dbg(iop_chan->device->common.dev, "%s slots_allocated %d
  ",

  		__func__, iop_chan->slots_allocated);

  	spin_unlock_bh(&iop_chan->lock);
  
  	/* one is ok since we left it on there on purpose */
  	if (in_use_descs > 1)
  		printk(KERN_ERR "IOP: Freeing %d in use descriptors!
  ",
  			in_use_descs - 1);
  }
  
  /**

   * iop_adma_status - poll the status of an ADMA transaction

   * @chan: ADMA channel handle
   * @cookie: ADMA transaction identifier

   * @txstate: a holder for the current state of the channel or NULL

   */

  static enum dma_status iop_adma_status(struct dma_chan *chan,

  					dma_cookie_t cookie,

  					struct dma_tx_state *txstate)

  {
  	struct iop_adma_chan *iop_chan = to_iop_adma_chan(chan);
  	dma_cookie_t last_used;
  	dma_cookie_t last_complete;
  	enum dma_status ret;
  
  	last_used = chan->cookie;
  	last_complete = iop_chan->completed_cookie;

  	dma_set_tx_state(txstate, last_complete, last_used, 0);

  	ret = dma_async_is_complete(cookie, last_complete, last_used);
  	if (ret == DMA_SUCCESS)
  		return ret;
  
  	iop_adma_slot_cleanup(iop_chan);
  
  	last_used = chan->cookie;
  	last_complete = iop_chan->completed_cookie;

  	dma_set_tx_state(txstate, last_complete, last_used, 0);

  
  	return dma_async_is_complete(cookie, last_complete, last_used);
  }
  
  static irqreturn_t iop_adma_eot_handler(int irq, void *data)
  {
  	struct iop_adma_chan *chan = data;

  	dev_dbg(chan->device->common.dev, "%s
  ", __func__);

  
  	tasklet_schedule(&chan->irq_tasklet);
  
  	iop_adma_device_clear_eot_status(chan);
  
  	return IRQ_HANDLED;
  }
  
  static irqreturn_t iop_adma_eoc_handler(int irq, void *data)
  {
  	struct iop_adma_chan *chan = data;

  	dev_dbg(chan->device->common.dev, "%s
  ", __func__);

  
  	tasklet_schedule(&chan->irq_tasklet);
  
  	iop_adma_device_clear_eoc_status(chan);
  
  	return IRQ_HANDLED;
  }
  
  static irqreturn_t iop_adma_err_handler(int irq, void *data)
  {
  	struct iop_adma_chan *chan = data;
  	unsigned long status = iop_chan_get_status(chan);
  
  	dev_printk(KERN_ERR, chan->device->common.dev,
  		"error ( %s%s%s%s%s%s%s)
  ",
  		iop_is_err_int_parity(status, chan) ? "int_parity " : "",
  		iop_is_err_mcu_abort(status, chan) ? "mcu_abort " : "",
  		iop_is_err_int_tabort(status, chan) ? "int_tabort " : "",
  		iop_is_err_int_mabort(status, chan) ? "int_mabort " : "",
  		iop_is_err_pci_tabort(status, chan) ? "pci_tabort " : "",
  		iop_is_err_pci_mabort(status, chan) ? "pci_mabort " : "",
  		iop_is_err_split_tx(status, chan) ? "split_tx " : "");
  
  	iop_adma_device_clear_err_status(chan);
  
  	BUG();
  
  	return IRQ_HANDLED;
  }
  
  static void iop_adma_issue_pending(struct dma_chan *chan)
  {
  	struct iop_adma_chan *iop_chan = to_iop_adma_chan(chan);
  
  	if (iop_chan->pending) {
  		iop_chan->pending = 0;
  		iop_chan_append(iop_chan);
  	}
  }
  
  /*
   * Perform a transaction to verify the HW works.
   */
  #define IOP_ADMA_TEST_SIZE 2000
  
  static int __devinit iop_adma_memcpy_self_test(struct iop_adma_device *device)
  {
  	int i;
  	void *src, *dest;
  	dma_addr_t src_dma, dest_dma;
  	struct dma_chan *dma_chan;
  	dma_cookie_t cookie;
  	struct dma_async_tx_descriptor *tx;
  	int err = 0;
  	struct iop_adma_chan *iop_chan;

  	dev_dbg(device->common.dev, "%s
  ", __func__);

  	src = kmalloc(IOP_ADMA_TEST_SIZE, GFP_KERNEL);

  	if (!src)
  		return -ENOMEM;

  	dest = kzalloc(IOP_ADMA_TEST_SIZE, GFP_KERNEL);

  	if (!dest) {
  		kfree(src);
  		return -ENOMEM;
  	}
  
  	/* Fill in src buffer */
  	for (i = 0; i < IOP_ADMA_TEST_SIZE; i++)
  		((u8 *) src)[i] = (u8)i;

  	/* Start copy, using first DMA channel */
  	dma_chan = container_of(device->common.channels.next,
  				struct dma_chan,
  				device_node);

  	if (iop_adma_alloc_chan_resources(dma_chan) < 1) {

  		err = -ENODEV;
  		goto out;
  	}

  	dest_dma = dma_map_single(dma_chan->device->dev, dest,
  				IOP_ADMA_TEST_SIZE, DMA_FROM_DEVICE);

  	src_dma = dma_map_single(dma_chan->device->dev, src,
  				IOP_ADMA_TEST_SIZE, DMA_TO_DEVICE);

  	tx = iop_adma_prep_dma_memcpy(dma_chan, dest_dma, src_dma,

  				      IOP_ADMA_TEST_SIZE,
  				      DMA_PREP_INTERRUPT | DMA_CTRL_ACK);

  
  	cookie = iop_adma_tx_submit(tx);
  	iop_adma_issue_pending(dma_chan);

  	msleep(1);

  	if (iop_adma_status(dma_chan, cookie, NULL) !=

  			DMA_SUCCESS) {
  		dev_printk(KERN_ERR, dma_chan->device->dev,
  			"Self-test copy timed out, disabling
  ");
  		err = -ENODEV;
  		goto free_resources;
  	}
  
  	iop_chan = to_iop_adma_chan(dma_chan);
  	dma_sync_single_for_cpu(&iop_chan->device->pdev->dev, dest_dma,
  		IOP_ADMA_TEST_SIZE, DMA_FROM_DEVICE);
  	if (memcmp(src, dest, IOP_ADMA_TEST_SIZE)) {
  		dev_printk(KERN_ERR, dma_chan->device->dev,
  			"Self-test copy failed compare, disabling
  ");
  		err = -ENODEV;
  		goto free_resources;
  	}
  
  free_resources:
  	iop_adma_free_chan_resources(dma_chan);
  out:
  	kfree(src);
  	kfree(dest);
  	return err;
  }
  
  #define IOP_ADMA_NUM_SRC_TEST 4 /* must be <= 15 */
  static int __devinit

  iop_adma_xor_val_self_test(struct iop_adma_device *device)

  {
  	int i, src_idx;
  	struct page *dest;
  	struct page *xor_srcs[IOP_ADMA_NUM_SRC_TEST];
  	struct page *zero_sum_srcs[IOP_ADMA_NUM_SRC_TEST + 1];

  	dma_addr_t dma_srcs[IOP_ADMA_NUM_SRC_TEST + 1];

  	dma_addr_t dma_addr, dest_dma;
  	struct dma_async_tx_descriptor *tx;
  	struct dma_chan *dma_chan;
  	dma_cookie_t cookie;
  	u8 cmp_byte = 0;
  	u32 cmp_word;
  	u32 zero_sum_result;
  	int err = 0;
  	struct iop_adma_chan *iop_chan;

  	dev_dbg(device->common.dev, "%s
  ", __func__);

  
  	for (src_idx = 0; src_idx < IOP_ADMA_NUM_SRC_TEST; src_idx++) {
  		xor_srcs[src_idx] = alloc_page(GFP_KERNEL);

  		if (!xor_srcs[src_idx]) {
  			while (src_idx--)

  				__free_page(xor_srcs[src_idx]);

  			return -ENOMEM;
  		}

  	}
  
  	dest = alloc_page(GFP_KERNEL);

  	if (!dest) {
  		while (src_idx--)

  			__free_page(xor_srcs[src_idx]);

  		return -ENOMEM;
  	}

  
  	/* Fill in src buffers */
  	for (src_idx = 0; src_idx < IOP_ADMA_NUM_SRC_TEST; src_idx++) {
  		u8 *ptr = page_address(xor_srcs[src_idx]);
  		for (i = 0; i < PAGE_SIZE; i++)
  			ptr[i] = (1 << src_idx);
  	}
  
  	for (src_idx = 0; src_idx < IOP_ADMA_NUM_SRC_TEST; src_idx++)
  		cmp_byte ^= (u8) (1 << src_idx);
  
  	cmp_word = (cmp_byte << 24) | (cmp_byte << 16) |
  			(cmp_byte << 8) | cmp_byte;
  
  	memset(page_address(dest), 0, PAGE_SIZE);
  
  	dma_chan = container_of(device->common.channels.next,
  				struct dma_chan,
  				device_node);

  	if (iop_adma_alloc_chan_resources(dma_chan) < 1) {

  		err = -ENODEV;
  		goto out;
  	}
  
  	/* test xor */

  	dest_dma = dma_map_page(dma_chan->device->dev, dest, 0,
  				PAGE_SIZE, DMA_FROM_DEVICE);

  	for (i = 0; i < IOP_ADMA_NUM_SRC_TEST; i++)
  		dma_srcs[i] = dma_map_page(dma_chan->device->dev, xor_srcs[i],
  					   0, PAGE_SIZE, DMA_TO_DEVICE);
  	tx = iop_adma_prep_dma_xor(dma_chan, dest_dma, dma_srcs,

  				   IOP_ADMA_NUM_SRC_TEST, PAGE_SIZE,
  				   DMA_PREP_INTERRUPT | DMA_CTRL_ACK);

  
  	cookie = iop_adma_tx_submit(tx);
  	iop_adma_issue_pending(dma_chan);

  	msleep(8);

  	if (iop_adma_status(dma_chan, cookie, NULL) !=

  		DMA_SUCCESS) {
  		dev_printk(KERN_ERR, dma_chan->device->dev,
  			"Self-test xor timed out, disabling
  ");
  		err = -ENODEV;
  		goto free_resources;
  	}
  
  	iop_chan = to_iop_adma_chan(dma_chan);
  	dma_sync_single_for_cpu(&iop_chan->device->pdev->dev, dest_dma,
  		PAGE_SIZE, DMA_FROM_DEVICE);
  	for (i = 0; i < (PAGE_SIZE / sizeof(u32)); i++) {
  		u32 *ptr = page_address(dest);
  		if (ptr[i] != cmp_word) {
  			dev_printk(KERN_ERR, dma_chan->device->dev,
  				"Self-test xor failed compare, disabling
  ");
  			err = -ENODEV;
  			goto free_resources;
  		}
  	}
  	dma_sync_single_for_device(&iop_chan->device->pdev->dev, dest_dma,
  		PAGE_SIZE, DMA_TO_DEVICE);
  
  	/* skip zero sum if the capability is not present */

  	if (!dma_has_cap(DMA_XOR_VAL, dma_chan->device->cap_mask))

  		goto free_resources;
  
  	/* zero sum the sources with the destintation page */
  	for (i = 0; i < IOP_ADMA_NUM_SRC_TEST; i++)
  		zero_sum_srcs[i] = xor_srcs[i];
  	zero_sum_srcs[i] = dest;
  
  	zero_sum_result = 1;

  	for (i = 0; i < IOP_ADMA_NUM_SRC_TEST + 1; i++)
  		dma_srcs[i] = dma_map_page(dma_chan->device->dev,
  					   zero_sum_srcs[i], 0, PAGE_SIZE,
  					   DMA_TO_DEVICE);

  	tx = iop_adma_prep_dma_xor_val(dma_chan, dma_srcs,
  				       IOP_ADMA_NUM_SRC_TEST + 1, PAGE_SIZE,
  				       &zero_sum_result,
  				       DMA_PREP_INTERRUPT | DMA_CTRL_ACK);

  
  	cookie = iop_adma_tx_submit(tx);
  	iop_adma_issue_pending(dma_chan);

  	msleep(8);

  	if (iop_adma_status(dma_chan, cookie, NULL) != DMA_SUCCESS) {

  		dev_printk(KERN_ERR, dma_chan->device->dev,
  			"Self-test zero sum timed out, disabling
  ");
  		err = -ENODEV;
  		goto free_resources;
  	}
  
  	if (zero_sum_result != 0) {
  		dev_printk(KERN_ERR, dma_chan->device->dev,
  			"Self-test zero sum failed compare, disabling
  ");
  		err = -ENODEV;
  		goto free_resources;
  	}
  
  	/* test memset */

  	dma_addr = dma_map_page(dma_chan->device->dev, dest, 0,
  			PAGE_SIZE, DMA_FROM_DEVICE);

  	tx = iop_adma_prep_dma_memset(dma_chan, dma_addr, 0, PAGE_SIZE,
  				      DMA_PREP_INTERRUPT | DMA_CTRL_ACK);

  
  	cookie = iop_adma_tx_submit(tx);
  	iop_adma_issue_pending(dma_chan);

  	msleep(8);

  	if (iop_adma_status(dma_chan, cookie, NULL) != DMA_SUCCESS) {

  		dev_printk(KERN_ERR, dma_chan->device->dev,
  			"Self-test memset timed out, disabling
  ");
  		err = -ENODEV;
  		goto free_resources;
  	}
  
  	for (i = 0; i < PAGE_SIZE/sizeof(u32); i++) {
  		u32 *ptr = page_address(dest);
  		if (ptr[i]) {
  			dev_printk(KERN_ERR, dma_chan->device->dev,
  				"Self-test memset failed compare, disabling
  ");
  			err = -ENODEV;
  			goto free_resources;
  		}
  	}
  
  	/* test for non-zero parity sum */
  	zero_sum_result = 0;

  	for (i = 0; i < IOP_ADMA_NUM_SRC_TEST + 1; i++)
  		dma_srcs[i] = dma_map_page(dma_chan->device->dev,
  					   zero_sum_srcs[i], 0, PAGE_SIZE,
  					   DMA_TO_DEVICE);

  	tx = iop_adma_prep_dma_xor_val(dma_chan, dma_srcs,
  				       IOP_ADMA_NUM_SRC_TEST + 1, PAGE_SIZE,
  				       &zero_sum_result,
  				       DMA_PREP_INTERRUPT | DMA_CTRL_ACK);

  
  	cookie = iop_adma_tx_submit(tx);
  	iop_adma_issue_pending(dma_chan);

  	msleep(8);

  	if (iop_adma_status(dma_chan, cookie, NULL) != DMA_SUCCESS) {

  		dev_printk(KERN_ERR, dma_chan->device->dev,
  			"Self-test non-zero sum timed out, disabling
  ");
  		err = -ENODEV;
  		goto free_resources;
  	}
  
  	if (zero_sum_result != 1) {
  		dev_printk(KERN_ERR, dma_chan->device->dev,
  			"Self-test non-zero sum failed compare, disabling
  ");
  		err = -ENODEV;
  		goto free_resources;
  	}
  
  free_resources:
  	iop_adma_free_chan_resources(dma_chan);
  out:
  	src_idx = IOP_ADMA_NUM_SRC_TEST;
  	while (src_idx--)
  		__free_page(xor_srcs[src_idx]);
  	__free_page(dest);
  	return err;
  }

  #ifdef CONFIG_RAID6_PQ

  static int __devinit
  iop_adma_pq_zero_sum_self_test(struct iop_adma_device *device)
  {
  	/* combined sources, software pq results, and extra hw pq results */
  	struct page *pq[IOP_ADMA_NUM_SRC_TEST+2+2];
  	/* ptr to the extra hw pq buffers defined above */
  	struct page **pq_hw = &pq[IOP_ADMA_NUM_SRC_TEST+2];
  	/* address conversion buffers (dma_map / page_address) */
  	void *pq_sw[IOP_ADMA_NUM_SRC_TEST+2];
  	dma_addr_t pq_src[IOP_ADMA_NUM_SRC_TEST];
  	dma_addr_t pq_dest[2];
  
  	int i;
  	struct dma_async_tx_descriptor *tx;
  	struct dma_chan *dma_chan;
  	dma_cookie_t cookie;
  	u32 zero_sum_result;
  	int err = 0;
  	struct device *dev;
  
  	dev_dbg(device->common.dev, "%s
  ", __func__);
  
  	for (i = 0; i < ARRAY_SIZE(pq); i++) {
  		pq[i] = alloc_page(GFP_KERNEL);
  		if (!pq[i]) {
  			while (i--)
  				__free_page(pq[i]);
  			return -ENOMEM;
  		}
  	}
  
  	/* Fill in src buffers */
  	for (i = 0; i < IOP_ADMA_NUM_SRC_TEST; i++) {
  		pq_sw[i] = page_address(pq[i]);
  		memset(pq_sw[i], 0x11111111 * (1<<i), PAGE_SIZE);
  	}
  	pq_sw[i] = page_address(pq[i]);
  	pq_sw[i+1] = page_address(pq[i+1]);
  
  	dma_chan = container_of(device->common.channels.next,
  				struct dma_chan,
  				device_node);
  	if (iop_adma_alloc_chan_resources(dma_chan) < 1) {
  		err = -ENODEV;
  		goto out;
  	}
  
  	dev = dma_chan->device->dev;
  
  	/* initialize the dests */
  	memset(page_address(pq_hw[0]), 0 , PAGE_SIZE);
  	memset(page_address(pq_hw[1]), 0 , PAGE_SIZE);
  
  	/* test pq */
  	pq_dest[0] = dma_map_page(dev, pq_hw[0], 0, PAGE_SIZE, DMA_FROM_DEVICE);
  	pq_dest[1] = dma_map_page(dev, pq_hw[1], 0, PAGE_SIZE, DMA_FROM_DEVICE);
  	for (i = 0; i < IOP_ADMA_NUM_SRC_TEST; i++)
  		pq_src[i] = dma_map_page(dev, pq[i], 0, PAGE_SIZE,
  					 DMA_TO_DEVICE);
  
  	tx = iop_adma_prep_dma_pq(dma_chan, pq_dest, pq_src,
  				  IOP_ADMA_NUM_SRC_TEST, (u8 *)raid6_gfexp,
  				  PAGE_SIZE,
  				  DMA_PREP_INTERRUPT |
  				  DMA_CTRL_ACK);
  
  	cookie = iop_adma_tx_submit(tx);
  	iop_adma_issue_pending(dma_chan);
  	msleep(8);

  	if (iop_adma_status(dma_chan, cookie, NULL) !=

  		DMA_SUCCESS) {
  		dev_err(dev, "Self-test pq timed out, disabling
  ");
  		err = -ENODEV;
  		goto free_resources;
  	}
  
  	raid6_call.gen_syndrome(IOP_ADMA_NUM_SRC_TEST+2, PAGE_SIZE, pq_sw);
  
  	if (memcmp(pq_sw[IOP_ADMA_NUM_SRC_TEST],
  		   page_address(pq_hw[0]), PAGE_SIZE) != 0) {
  		dev_err(dev, "Self-test p failed compare, disabling
  ");
  		err = -ENODEV;
  		goto free_resources;
  	}
  	if (memcmp(pq_sw[IOP_ADMA_NUM_SRC_TEST+1],
  		   page_address(pq_hw[1]), PAGE_SIZE) != 0) {
  		dev_err(dev, "Self-test q failed compare, disabling
  ");
  		err = -ENODEV;
  		goto free_resources;
  	}
  
  	/* test correct zero sum using the software generated pq values */
  	for (i = 0; i < IOP_ADMA_NUM_SRC_TEST + 2; i++)
  		pq_src[i] = dma_map_page(dev, pq[i], 0, PAGE_SIZE,
  					 DMA_TO_DEVICE);
  
  	zero_sum_result = ~0;
  	tx = iop_adma_prep_dma_pq_val(dma_chan, &pq_src[IOP_ADMA_NUM_SRC_TEST],
  				      pq_src, IOP_ADMA_NUM_SRC_TEST,
  				      raid6_gfexp, PAGE_SIZE, &zero_sum_result,
  				      DMA_PREP_INTERRUPT|DMA_CTRL_ACK);
  
  	cookie = iop_adma_tx_submit(tx);
  	iop_adma_issue_pending(dma_chan);
  	msleep(8);

  	if (iop_adma_status(dma_chan, cookie, NULL) !=

  		DMA_SUCCESS) {
  		dev_err(dev, "Self-test pq-zero-sum timed out, disabling
  ");
  		err = -ENODEV;
  		goto free_resources;
  	}
  
  	if (zero_sum_result != 0) {
  		dev_err(dev, "Self-test pq-zero-sum failed to validate: %x
  ",
  			zero_sum_result);
  		err = -ENODEV;
  		goto free_resources;
  	}
  
  	/* test incorrect zero sum */
  	i = IOP_ADMA_NUM_SRC_TEST;
  	memset(pq_sw[i] + 100, 0, 100);
  	memset(pq_sw[i+1] + 200, 0, 200);
  	for (i = 0; i < IOP_ADMA_NUM_SRC_TEST + 2; i++)
  		pq_src[i] = dma_map_page(dev, pq[i], 0, PAGE_SIZE,
  					 DMA_TO_DEVICE);
  
  	zero_sum_result = 0;
  	tx = iop_adma_prep_dma_pq_val(dma_chan, &pq_src[IOP_ADMA_NUM_SRC_TEST],
  				      pq_src, IOP_ADMA_NUM_SRC_TEST,
  				      raid6_gfexp, PAGE_SIZE, &zero_sum_result,
  				      DMA_PREP_INTERRUPT|DMA_CTRL_ACK);
  
  	cookie = iop_adma_tx_submit(tx);
  	iop_adma_issue_pending(dma_chan);
  	msleep(8);

  	if (iop_adma_status(dma_chan, cookie, NULL) !=

  		DMA_SUCCESS) {
  		dev_err(dev, "Self-test !pq-zero-sum timed out, disabling
  ");
  		err = -ENODEV;
  		goto free_resources;
  	}
  
  	if (zero_sum_result != (SUM_CHECK_P_RESULT | SUM_CHECK_Q_RESULT)) {
  		dev_err(dev, "Self-test !pq-zero-sum failed to validate: %x
  ",
  			zero_sum_result);
  		err = -ENODEV;
  		goto free_resources;
  	}
  
  free_resources:
  	iop_adma_free_chan_resources(dma_chan);
  out:
  	i = ARRAY_SIZE(pq);
  	while (i--)
  		__free_page(pq[i]);
  	return err;
  }
  #endif

  static int __devexit iop_adma_remove(struct platform_device *dev)
  {
  	struct iop_adma_device *device = platform_get_drvdata(dev);
  	struct dma_chan *chan, *_chan;
  	struct iop_adma_chan *iop_chan;

  	struct iop_adma_platform_data *plat_data = dev->dev.platform_data;
  
  	dma_async_device_unregister(&device->common);

  	dma_free_coherent(&dev->dev, plat_data->pool_size,
  			device->dma_desc_pool_virt, device->dma_desc_pool);

  	list_for_each_entry_safe(chan, _chan, &device->common.channels,
  				device_node) {
  		iop_chan = to_iop_adma_chan(chan);
  		list_del(&chan->device_node);
  		kfree(iop_chan);
  	}
  	kfree(device);
  
  	return 0;
  }
  
  static int __devinit iop_adma_probe(struct platform_device *pdev)
  {
  	struct resource *res;
  	int ret = 0, i;
  	struct iop_adma_device *adev;
  	struct iop_adma_chan *iop_chan;
  	struct dma_device *dma_dev;
  	struct iop_adma_platform_data *plat_data = pdev->dev.platform_data;
  
  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	if (!res)
  		return -ENODEV;
  
  	if (!devm_request_mem_region(&pdev->dev, res->start,

  				resource_size(res), pdev->name))

  		return -EBUSY;
  
  	adev = kzalloc(sizeof(*adev), GFP_KERNEL);
  	if (!adev)
  		return -ENOMEM;
  	dma_dev = &adev->common;
  
  	/* allocate coherent memory for hardware descriptors
  	 * note: writecombine gives slightly better performance, but
  	 * requires that we explicitly flush the writes
  	 */
  	if ((adev->dma_desc_pool_virt = dma_alloc_writecombine(&pdev->dev,
  					plat_data->pool_size,
  					&adev->dma_desc_pool,
  					GFP_KERNEL)) == NULL) {
  		ret = -ENOMEM;
  		goto err_free_adev;
  	}
  
  	dev_dbg(&pdev->dev, "%s: allocted descriptor pool virt %p phys %p
  ",

  		__func__, adev->dma_desc_pool_virt,

  		(void *) adev->dma_desc_pool);
  
  	adev->id = plat_data->hw_id;
  
  	/* discover transaction capabilites from the platform data */
  	dma_dev->cap_mask = plat_data->cap_mask;
  
  	adev->pdev = pdev;
  	platform_set_drvdata(pdev, adev);
  
  	INIT_LIST_HEAD(&dma_dev->channels);
  
  	/* set base routines */
  	dma_dev->device_alloc_chan_resources = iop_adma_alloc_chan_resources;
  	dma_dev->device_free_chan_resources = iop_adma_free_chan_resources;

  	dma_dev->device_tx_status = iop_adma_status;

  	dma_dev->device_issue_pending = iop_adma_issue_pending;

  	dma_dev->dev = &pdev->dev;
  
  	/* set prep routines based on capability */
  	if (dma_has_cap(DMA_MEMCPY, dma_dev->cap_mask))
  		dma_dev->device_prep_dma_memcpy = iop_adma_prep_dma_memcpy;
  	if (dma_has_cap(DMA_MEMSET, dma_dev->cap_mask))
  		dma_dev->device_prep_dma_memset = iop_adma_prep_dma_memset;
  	if (dma_has_cap(DMA_XOR, dma_dev->cap_mask)) {
  		dma_dev->max_xor = iop_adma_get_max_xor();
  		dma_dev->device_prep_dma_xor = iop_adma_prep_dma_xor;
  	}

  	if (dma_has_cap(DMA_XOR_VAL, dma_dev->cap_mask))
  		dma_dev->device_prep_dma_xor_val =
  			iop_adma_prep_dma_xor_val;

  	if (dma_has_cap(DMA_PQ, dma_dev->cap_mask)) {
  		dma_set_maxpq(dma_dev, iop_adma_get_max_pq(), 0);
  		dma_dev->device_prep_dma_pq = iop_adma_prep_dma_pq;
  	}
  	if (dma_has_cap(DMA_PQ_VAL, dma_dev->cap_mask))
  		dma_dev->device_prep_dma_pq_val =
  			iop_adma_prep_dma_pq_val;

  	if (dma_has_cap(DMA_INTERRUPT, dma_dev->cap_mask))
  		dma_dev->device_prep_dma_interrupt =
  			iop_adma_prep_dma_interrupt;
  
  	iop_chan = kzalloc(sizeof(*iop_chan), GFP_KERNEL);
  	if (!iop_chan) {
  		ret = -ENOMEM;
  		goto err_free_dma;
  	}
  	iop_chan->device = adev;
  
  	iop_chan->mmr_base = devm_ioremap(&pdev->dev, res->start,

  					resource_size(res));

  	if (!iop_chan->mmr_base) {
  		ret = -ENOMEM;
  		goto err_free_iop_chan;
  	}
  	tasklet_init(&iop_chan->irq_tasklet, iop_adma_tasklet, (unsigned long)
  		iop_chan);
  
  	/* clear errors before enabling interrupts */
  	iop_adma_device_clear_err_status(iop_chan);
  
  	for (i = 0; i < 3; i++) {
  		irq_handler_t handler[] = { iop_adma_eot_handler,
  					iop_adma_eoc_handler,
  					iop_adma_err_handler };
  		int irq = platform_get_irq(pdev, i);
  		if (irq < 0) {
  			ret = -ENXIO;
  			goto err_free_iop_chan;
  		} else {
  			ret = devm_request_irq(&pdev->dev, irq,
  					handler[i], 0, pdev->name, iop_chan);
  			if (ret)
  				goto err_free_iop_chan;
  		}
  	}
  
  	spin_lock_init(&iop_chan->lock);

  	INIT_LIST_HEAD(&iop_chan->chain);
  	INIT_LIST_HEAD(&iop_chan->all_slots);

  	iop_chan->common.device = dma_dev;
  	list_add_tail(&iop_chan->common.device_node, &dma_dev->channels);
  
  	if (dma_has_cap(DMA_MEMCPY, dma_dev->cap_mask)) {
  		ret = iop_adma_memcpy_self_test(adev);
  		dev_dbg(&pdev->dev, "memcpy self test returned %d
  ", ret);
  		if (ret)
  			goto err_free_iop_chan;
  	}
  
  	if (dma_has_cap(DMA_XOR, dma_dev->cap_mask) ||

  	    dma_has_cap(DMA_MEMSET, dma_dev->cap_mask)) {

  		ret = iop_adma_xor_val_self_test(adev);

  		dev_dbg(&pdev->dev, "xor self test returned %d
  ", ret);
  		if (ret)
  			goto err_free_iop_chan;
  	}

  	if (dma_has_cap(DMA_PQ, dma_dev->cap_mask) &&
  	    dma_has_cap(DMA_PQ_VAL, dma_dev->cap_mask)) {

  		#ifdef CONFIG_RAID6_PQ

  		ret = iop_adma_pq_zero_sum_self_test(adev);
  		dev_dbg(&pdev->dev, "pq self test returned %d
  ", ret);
  		#else
  		/* can not test raid6, so do not publish capability */
  		dma_cap_clear(DMA_PQ, dma_dev->cap_mask);
  		dma_cap_clear(DMA_PQ_VAL, dma_dev->cap_mask);
  		ret = 0;
  		#endif
  		if (ret)
  			goto err_free_iop_chan;
  	}

  	dev_printk(KERN_INFO, &pdev->dev, "Intel(R) IOP: "

  	  "( %s%s%s%s%s%s%s)
  ",

  	  dma_has_cap(DMA_PQ, dma_dev->cap_mask) ? "pq " : "",

  	  dma_has_cap(DMA_PQ_VAL, dma_dev->cap_mask) ? "pq_val " : "",

  	  dma_has_cap(DMA_XOR, dma_dev->cap_mask) ? "xor " : "",

  	  dma_has_cap(DMA_XOR_VAL, dma_dev->cap_mask) ? "xor_val " : "",

  	  dma_has_cap(DMA_MEMSET, dma_dev->cap_mask)  ? "fill " : "",

  	  dma_has_cap(DMA_MEMCPY, dma_dev->cap_mask) ? "cpy " : "",
  	  dma_has_cap(DMA_INTERRUPT, dma_dev->cap_mask) ? "intr " : "");
  
  	dma_async_device_register(dma_dev);
  	goto out;
  
   err_free_iop_chan:
  	kfree(iop_chan);
   err_free_dma:
  	dma_free_coherent(&adev->pdev->dev, plat_data->pool_size,
  			adev->dma_desc_pool_virt, adev->dma_desc_pool);
   err_free_adev:
  	kfree(adev);
   out:
  	return ret;
  }
  
  static void iop_chan_start_null_memcpy(struct iop_adma_chan *iop_chan)
  {
  	struct iop_adma_desc_slot *sw_desc, *grp_start;
  	dma_cookie_t cookie;
  	int slot_cnt, slots_per_op;

  	dev_dbg(iop_chan->device->common.dev, "%s
  ", __func__);

  
  	spin_lock_bh(&iop_chan->lock);
  	slot_cnt = iop_chan_memcpy_slot_count(0, &slots_per_op);
  	sw_desc = iop_adma_alloc_slots(iop_chan, slot_cnt, slots_per_op);
  	if (sw_desc) {
  		grp_start = sw_desc->group_head;

  		list_splice_init(&sw_desc->tx_list, &iop_chan->chain);

  		async_tx_ack(&sw_desc->async_tx);

  		iop_desc_init_memcpy(grp_start, 0);
  		iop_desc_set_byte_count(grp_start, iop_chan, 0);
  		iop_desc_set_dest_addr(grp_start, iop_chan, 0);
  		iop_desc_set_memcpy_src_addr(grp_start, 0);
  
  		cookie = iop_chan->common.cookie;
  		cookie++;
  		if (cookie <= 1)
  			cookie = 2;
  
  		/* initialize the completed cookie to be less than
  		 * the most recently used cookie
  		 */
  		iop_chan->completed_cookie = cookie - 1;
  		iop_chan->common.cookie = sw_desc->async_tx.cookie = cookie;
  
  		/* channel should not be busy */
  		BUG_ON(iop_chan_is_busy(iop_chan));
  
  		/* clear any prior error-status bits */
  		iop_adma_device_clear_err_status(iop_chan);
  
  		/* disable operation */
  		iop_chan_disable(iop_chan);
  
  		/* set the descriptor address */
  		iop_chan_set_next_descriptor(iop_chan, sw_desc->async_tx.phys);
  
  		/* 1/ don't add pre-chained descriptors
  		 * 2/ dummy read to flush next_desc write
  		 */
  		BUG_ON(iop_desc_get_next_desc(sw_desc));
  
  		/* run the descriptor */
  		iop_chan_enable(iop_chan);
  	} else
  		dev_printk(KERN_ERR, iop_chan->device->common.dev,
  			 "failed to allocate null descriptor
  ");
  	spin_unlock_bh(&iop_chan->lock);
  }
  
  static void iop_chan_start_null_xor(struct iop_adma_chan *iop_chan)
  {
  	struct iop_adma_desc_slot *sw_desc, *grp_start;
  	dma_cookie_t cookie;
  	int slot_cnt, slots_per_op;

  	dev_dbg(iop_chan->device->common.dev, "%s
  ", __func__);

  
  	spin_lock_bh(&iop_chan->lock);
  	slot_cnt = iop_chan_xor_slot_count(0, 2, &slots_per_op);
  	sw_desc = iop_adma_alloc_slots(iop_chan, slot_cnt, slots_per_op);
  	if (sw_desc) {
  		grp_start = sw_desc->group_head;

  		list_splice_init(&sw_desc->tx_list, &iop_chan->chain);

  		async_tx_ack(&sw_desc->async_tx);

  		iop_desc_init_null_xor(grp_start, 2, 0);
  		iop_desc_set_byte_count(grp_start, iop_chan, 0);
  		iop_desc_set_dest_addr(grp_start, iop_chan, 0);
  		iop_desc_set_xor_src_addr(grp_start, 0, 0);
  		iop_desc_set_xor_src_addr(grp_start, 1, 0);
  
  		cookie = iop_chan->common.cookie;
  		cookie++;
  		if (cookie <= 1)
  			cookie = 2;
  
  		/* initialize the completed cookie to be less than
  		 * the most recently used cookie
  		 */
  		iop_chan->completed_cookie = cookie - 1;
  		iop_chan->common.cookie = sw_desc->async_tx.cookie = cookie;
  
  		/* channel should not be busy */
  		BUG_ON(iop_chan_is_busy(iop_chan));
  
  		/* clear any prior error-status bits */
  		iop_adma_device_clear_err_status(iop_chan);
  
  		/* disable operation */
  		iop_chan_disable(iop_chan);
  
  		/* set the descriptor address */
  		iop_chan_set_next_descriptor(iop_chan, sw_desc->async_tx.phys);
  
  		/* 1/ don't add pre-chained descriptors
  		 * 2/ dummy read to flush next_desc write
  		 */
  		BUG_ON(iop_desc_get_next_desc(sw_desc));
  
  		/* run the descriptor */
  		iop_chan_enable(iop_chan);
  	} else
  		dev_printk(KERN_ERR, iop_chan->device->common.dev,
  			"failed to allocate null descriptor
  ");
  	spin_unlock_bh(&iop_chan->lock);
  }

  MODULE_ALIAS("platform:iop-adma");

  static struct platform_driver iop_adma_driver = {
  	.probe		= iop_adma_probe,

  	.remove		= __devexit_p(iop_adma_remove),

  	.driver		= {
  		.owner	= THIS_MODULE,
  		.name	= "iop-adma",
  	},
  };
  
  static int __init iop_adma_init (void)
  {

  	return platform_driver_register(&iop_adma_driver);
  }
  
  static void __exit iop_adma_exit (void)
  {
  	platform_driver_unregister(&iop_adma_driver);
  	return;
  }

  module_exit(iop_adma_exit);

  module_init(iop_adma_init);

  
  MODULE_AUTHOR("Intel Corporation");
  MODULE_DESCRIPTION("IOP ADMA Engine Driver");
  MODULE_LICENSE("GPL");