/*
   * offload engine driver for the Marvell XOR engine
   * Copyright (C) 2007, 2008, Marvell International Ltd.
   *
   * 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.

   */
  
  #include <linux/init.h>

  #include <linux/slab.h>

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

  #include <linux/of_device.h>

  #include <linux/platform_device.h>
  #include <linux/memory.h>

  #include <linux/clk.h>

  #include <linux/of.h>
  #include <linux/of_irq.h>
  #include <linux/irqdomain.h>

  #include <linux/cpumask.h>

  #include <linux/platform_data/dma-mv_xor.h>

  
  #include "dmaengine.h"

  #include "mv_xor.h"

  enum mv_xor_type {
  	XOR_ORION,
  	XOR_ARMADA_38X,

  	XOR_ARMADA_37XX,

  };

  enum mv_xor_mode {
  	XOR_MODE_IN_REG,
  	XOR_MODE_IN_DESC,
  };

  static void mv_xor_issue_pending(struct dma_chan *chan);
  
  #define to_mv_xor_chan(chan)		\

  	container_of(chan, struct mv_xor_chan, dmachan)

  
  #define to_mv_xor_slot(tx)		\
  	container_of(tx, struct mv_xor_desc_slot, async_tx)

  #define mv_chan_to_devp(chan)           \

  	((chan)->dmadev.dev)

  static void mv_desc_init(struct mv_xor_desc_slot *desc,

  			 dma_addr_t addr, u32 byte_count,
  			 enum dma_ctrl_flags flags)

  {
  	struct mv_xor_desc *hw_desc = desc->hw_desc;

  	hw_desc->status = XOR_DESC_DMA_OWNED;

  	hw_desc->phy_next_desc = 0;

  	/* Enable end-of-descriptor interrupts only for DMA_PREP_INTERRUPT */
  	hw_desc->desc_command = (flags & DMA_PREP_INTERRUPT) ?
  				XOR_DESC_EOD_INT_EN : 0;

  	hw_desc->phy_dest_addr = addr;

  	hw_desc->byte_count = byte_count;
  }

  static void mv_desc_set_mode(struct mv_xor_desc_slot *desc)
  {
  	struct mv_xor_desc *hw_desc = desc->hw_desc;
  
  	switch (desc->type) {
  	case DMA_XOR:
  	case DMA_INTERRUPT:
  		hw_desc->desc_command |= XOR_DESC_OPERATION_XOR;
  		break;
  	case DMA_MEMCPY:
  		hw_desc->desc_command |= XOR_DESC_OPERATION_MEMCPY;
  		break;
  	default:
  		BUG();
  		return;
  	}
  }

  static void mv_desc_set_next_desc(struct mv_xor_desc_slot *desc,
  				  u32 next_desc_addr)
  {
  	struct mv_xor_desc *hw_desc = desc->hw_desc;
  	BUG_ON(hw_desc->phy_next_desc);
  	hw_desc->phy_next_desc = next_desc_addr;
  }

  static void mv_desc_set_src_addr(struct mv_xor_desc_slot *desc,
  				 int index, dma_addr_t addr)
  {
  	struct mv_xor_desc *hw_desc = desc->hw_desc;

  	hw_desc->phy_src_addr[mv_phy_src_idx(index)] = addr;

  	if (desc->type == DMA_XOR)
  		hw_desc->desc_command |= (1 << index);
  }
  
  static u32 mv_chan_get_current_desc(struct mv_xor_chan *chan)
  {

  	return readl_relaxed(XOR_CURR_DESC(chan));

  }
  
  static void mv_chan_set_next_descriptor(struct mv_xor_chan *chan,
  					u32 next_desc_addr)
  {

  	writel_relaxed(next_desc_addr, XOR_NEXT_DESC(chan));

  }

  static void mv_chan_unmask_interrupts(struct mv_xor_chan *chan)
  {

  	u32 val = readl_relaxed(XOR_INTR_MASK(chan));

  	val |= XOR_INTR_MASK_VALUE << (chan->idx * 16);

  	writel_relaxed(val, XOR_INTR_MASK(chan));

  }
  
  static u32 mv_chan_get_intr_cause(struct mv_xor_chan *chan)
  {

  	u32 intr_cause = readl_relaxed(XOR_INTR_CAUSE(chan));

  	intr_cause = (intr_cause >> (chan->idx * 16)) & 0xFFFF;
  	return intr_cause;
  }

  static void mv_chan_clear_eoc_cause(struct mv_xor_chan *chan)

  {

  	u32 val;
  
  	val = XOR_INT_END_OF_DESC | XOR_INT_END_OF_CHAIN | XOR_INT_STOPPED;
  	val = ~(val << (chan->idx * 16));

  	dev_dbg(mv_chan_to_devp(chan), "%s, val 0x%08x
  ", __func__, val);

  	writel_relaxed(val, XOR_INTR_CAUSE(chan));

  }

  static void mv_chan_clear_err_status(struct mv_xor_chan *chan)

  {
  	u32 val = 0xFFFF0000 >> (chan->idx * 16);

  	writel_relaxed(val, XOR_INTR_CAUSE(chan));

  }

  static void mv_chan_set_mode(struct mv_xor_chan *chan,

  			     u32 op_mode)

  {

  	u32 config = readl_relaxed(XOR_CONFIG(chan));

  	config &= ~0x7;
  	config |= op_mode;

  #if defined(__BIG_ENDIAN)
  	config |= XOR_DESCRIPTOR_SWAP;
  #else
  	config &= ~XOR_DESCRIPTOR_SWAP;
  #endif

  	writel_relaxed(config, XOR_CONFIG(chan));

  }
  
  static void mv_chan_activate(struct mv_xor_chan *chan)
  {

  	dev_dbg(mv_chan_to_devp(chan), " activate chan.
  ");

  
  	/* writel ensures all descriptors are flushed before activation */
  	writel(BIT(0), XOR_ACTIVATION(chan));

  }
  
  static char mv_chan_is_busy(struct mv_xor_chan *chan)
  {

  	u32 state = readl_relaxed(XOR_ACTIVATION(chan));

  
  	state = (state >> 4) & 0x3;
  
  	return (state == 1) ? 1 : 0;
  }

  /*

   * mv_chan_start_new_chain - program the engine to operate on new
   * chain headed by sw_desc

   * Caller must hold &mv_chan->lock while calling this function
   */

  static void mv_chan_start_new_chain(struct mv_xor_chan *mv_chan,
  				    struct mv_xor_desc_slot *sw_desc)

  {

  	dev_dbg(mv_chan_to_devp(mv_chan), "%s %d: sw_desc %p
  ",

  		__func__, __LINE__, sw_desc);

  	/* set the hardware chain */
  	mv_chan_set_next_descriptor(mv_chan, sw_desc->async_tx.phys);

  	mv_chan->pending++;

  	mv_xor_issue_pending(&mv_chan->dmachan);

  }
  
  static dma_cookie_t

  mv_desc_run_tx_complete_actions(struct mv_xor_desc_slot *desc,
  				struct mv_xor_chan *mv_chan,
  				dma_cookie_t cookie)

  {
  	BUG_ON(desc->async_tx.cookie < 0);
  
  	if (desc->async_tx.cookie > 0) {
  		cookie = desc->async_tx.cookie;

  		dma_descriptor_unmap(&desc->async_tx);

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

  		dmaengine_desc_get_callback_invoke(&desc->async_tx, NULL);

  	}
  
  	/* run dependent operations */

  	dma_run_dependencies(&desc->async_tx);

  
  	return cookie;
  }
  
  static int

  mv_chan_clean_completed_slots(struct mv_xor_chan *mv_chan)

  {
  	struct mv_xor_desc_slot *iter, *_iter;

  	dev_dbg(mv_chan_to_devp(mv_chan), "%s %d
  ", __func__, __LINE__);

  	list_for_each_entry_safe(iter, _iter, &mv_chan->completed_slots,

  				 node) {

  		if (async_tx_test_ack(&iter->async_tx)) {

  			list_move_tail(&iter->node, &mv_chan->free_slots);

  			if (!list_empty(&iter->sg_tx_list)) {
  				list_splice_tail_init(&iter->sg_tx_list,
  							&mv_chan->free_slots);
  			}
  		}

  	}
  	return 0;
  }
  
  static int

  mv_desc_clean_slot(struct mv_xor_desc_slot *desc,
  		   struct mv_xor_chan *mv_chan)

  {

  	dev_dbg(mv_chan_to_devp(mv_chan), "%s %d: desc %p flags %d
  ",

  		__func__, __LINE__, desc, desc->async_tx.flags);

  	/* the client is allowed to attach dependent operations
  	 * until 'ack' is set
  	 */

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

  		/* move this slot to the completed_slots */

  		list_move_tail(&desc->node, &mv_chan->completed_slots);

  		if (!list_empty(&desc->sg_tx_list)) {
  			list_splice_tail_init(&desc->sg_tx_list,
  					      &mv_chan->completed_slots);
  		}
  	} else {

  		list_move_tail(&desc->node, &mv_chan->free_slots);

  		if (!list_empty(&desc->sg_tx_list)) {
  			list_splice_tail_init(&desc->sg_tx_list,
  					      &mv_chan->free_slots);
  		}
  	}

  	return 0;
  }

  /* This function must be called with the mv_xor_chan spinlock held */

  static void mv_chan_slot_cleanup(struct mv_xor_chan *mv_chan)

  {
  	struct mv_xor_desc_slot *iter, *_iter;
  	dma_cookie_t cookie = 0;
  	int busy = mv_chan_is_busy(mv_chan);
  	u32 current_desc = mv_chan_get_current_desc(mv_chan);

  	int current_cleaned = 0;
  	struct mv_xor_desc *hw_desc;

  	dev_dbg(mv_chan_to_devp(mv_chan), "%s %d
  ", __func__, __LINE__);
  	dev_dbg(mv_chan_to_devp(mv_chan), "current_desc %x
  ", current_desc);

  	mv_chan_clean_completed_slots(mv_chan);

  
  	/* free completed slots from the chain starting with
  	 * the oldest descriptor
  	 */
  
  	list_for_each_entry_safe(iter, _iter, &mv_chan->chain,

  				 node) {

  		/* clean finished descriptors */
  		hw_desc = iter->hw_desc;
  		if (hw_desc->status & XOR_DESC_SUCCESS) {

  			cookie = mv_desc_run_tx_complete_actions(iter, mv_chan,
  								 cookie);

  			/* done processing desc, clean slot */

  			mv_desc_clean_slot(iter, mv_chan);

  
  			/* break if we did cleaned the current */
  			if (iter->async_tx.phys == current_desc) {
  				current_cleaned = 1;
  				break;
  			}
  		} else {
  			if (iter->async_tx.phys == current_desc) {
  				current_cleaned = 0;

  				break;

  			}

  		}

  	}
  
  	if ((busy == 0) && !list_empty(&mv_chan->chain)) {

  		if (current_cleaned) {
  			/*
  			 * current descriptor cleaned and removed, run
  			 * from list head
  			 */
  			iter = list_entry(mv_chan->chain.next,
  					  struct mv_xor_desc_slot,

  					  node);

  			mv_chan_start_new_chain(mv_chan, iter);

  		} else {

  			if (!list_is_last(&iter->node, &mv_chan->chain)) {

  				/*
  				 * descriptors are still waiting after
  				 * current, trigger them
  				 */

  				iter = list_entry(iter->node.next,

  						  struct mv_xor_desc_slot,

  						  node);

  				mv_chan_start_new_chain(mv_chan, iter);

  			} else {
  				/*
  				 * some descriptors are still waiting
  				 * to be cleaned
  				 */
  				tasklet_schedule(&mv_chan->irq_tasklet);
  			}
  		}

  	}
  
  	if (cookie > 0)

  		mv_chan->dmachan.completed_cookie = cookie;

  }

  static void mv_xor_tasklet(unsigned long data)
  {
  	struct mv_xor_chan *chan = (struct mv_xor_chan *) data;

  
  	spin_lock_bh(&chan->lock);

  	mv_chan_slot_cleanup(chan);

  	spin_unlock_bh(&chan->lock);

  }
  
  static struct mv_xor_desc_slot *

  mv_chan_alloc_slot(struct mv_xor_chan *mv_chan)

  {

  	struct mv_xor_desc_slot *iter;

  	spin_lock_bh(&mv_chan->lock);
  
  	if (!list_empty(&mv_chan->free_slots)) {
  		iter = list_first_entry(&mv_chan->free_slots,
  					struct mv_xor_desc_slot,
  					node);
  
  		list_move_tail(&iter->node, &mv_chan->allocated_slots);
  
  		spin_unlock_bh(&mv_chan->lock);

  		/* pre-ack descriptor */
  		async_tx_ack(&iter->async_tx);

  		iter->async_tx.cookie = -EBUSY;

  
  		return iter;

  	}

  
  	spin_unlock_bh(&mv_chan->lock);

  
  	/* try to free some slots if the allocation fails */
  	tasklet_schedule(&mv_chan->irq_tasklet);
  
  	return NULL;
  }

  /************************ DMA engine API functions ****************************/
  static dma_cookie_t
  mv_xor_tx_submit(struct dma_async_tx_descriptor *tx)
  {
  	struct mv_xor_desc_slot *sw_desc = to_mv_xor_slot(tx);
  	struct mv_xor_chan *mv_chan = to_mv_xor_chan(tx->chan);

  	struct mv_xor_desc_slot *old_chain_tail;

  	dma_cookie_t cookie;
  	int new_hw_chain = 1;

  	dev_dbg(mv_chan_to_devp(mv_chan),

  		"%s sw_desc %p: async_tx %p
  ",
  		__func__, sw_desc, &sw_desc->async_tx);

  	spin_lock_bh(&mv_chan->lock);

  	cookie = dma_cookie_assign(tx);

  
  	if (list_empty(&mv_chan->chain))

  		list_move_tail(&sw_desc->node, &mv_chan->chain);

  	else {
  		new_hw_chain = 0;
  
  		old_chain_tail = list_entry(mv_chan->chain.prev,
  					    struct mv_xor_desc_slot,

  					    node);
  		list_move_tail(&sw_desc->node, &mv_chan->chain);

  		dev_dbg(mv_chan_to_devp(mv_chan), "Append to last desc %pa
  ",
  			&old_chain_tail->async_tx.phys);

  
  		/* fix up the hardware chain */

  		mv_desc_set_next_desc(old_chain_tail, sw_desc->async_tx.phys);

  
  		/* if the channel is not busy */
  		if (!mv_chan_is_busy(mv_chan)) {
  			u32 current_desc = mv_chan_get_current_desc(mv_chan);
  			/*
  			 * and the curren desc is the end of the chain before
  			 * the append, then we need to start the channel
  			 */
  			if (current_desc == old_chain_tail->async_tx.phys)
  				new_hw_chain = 1;
  		}
  	}
  
  	if (new_hw_chain)

  		mv_chan_start_new_chain(mv_chan, sw_desc);

  	spin_unlock_bh(&mv_chan->lock);
  
  	return cookie;
  }
  
  /* returns the number of allocated descriptors */

  static int mv_xor_alloc_chan_resources(struct dma_chan *chan)

  {

  	void *virt_desc;
  	dma_addr_t dma_desc;

  	int idx;
  	struct mv_xor_chan *mv_chan = to_mv_xor_chan(chan);
  	struct mv_xor_desc_slot *slot = NULL;

  	int num_descs_in_pool = MV_XOR_POOL_SIZE/MV_XOR_SLOT_SIZE;

  
  	/* Allocate descriptor slots */
  	idx = mv_chan->slots_allocated;
  	while (idx < num_descs_in_pool) {
  		slot = kzalloc(sizeof(*slot), GFP_KERNEL);
  		if (!slot) {

  			dev_info(mv_chan_to_devp(mv_chan),
  				 "channel only initialized %d descriptor slots",
  				 idx);

  			break;
  		}

  		virt_desc = mv_chan->dma_desc_pool_virt;
  		slot->hw_desc = virt_desc + idx * MV_XOR_SLOT_SIZE;

  
  		dma_async_tx_descriptor_init(&slot->async_tx, chan);
  		slot->async_tx.tx_submit = mv_xor_tx_submit;

  		INIT_LIST_HEAD(&slot->node);

  		INIT_LIST_HEAD(&slot->sg_tx_list);

  		dma_desc = mv_chan->dma_desc_pool;
  		slot->async_tx.phys = dma_desc + idx * MV_XOR_SLOT_SIZE;

  		slot->idx = idx++;
  
  		spin_lock_bh(&mv_chan->lock);
  		mv_chan->slots_allocated = idx;

  		list_add_tail(&slot->node, &mv_chan->free_slots);

  		spin_unlock_bh(&mv_chan->lock);
  	}

  	dev_dbg(mv_chan_to_devp(mv_chan),

  		"allocated %d descriptor slots
  ",
  		mv_chan->slots_allocated);

  
  	return mv_chan->slots_allocated ? : -ENOMEM;
  }

  /*
   * Check if source or destination is an PCIe/IO address (non-SDRAM) and add
   * a new MBus window if necessary. Use a cache for these check so that
   * the MMIO mapped registers don't have to be accessed for this check
   * to speed up this process.
   */
  static int mv_xor_add_io_win(struct mv_xor_chan *mv_chan, u32 addr)
  {
  	struct mv_xor_device *xordev = mv_chan->xordev;
  	void __iomem *base = mv_chan->mmr_high_base;
  	u32 win_enable;
  	u32 size;
  	u8 target, attr;
  	int ret;
  	int i;
  
  	/* Nothing needs to get done for the Armada 3700 */
  	if (xordev->xor_type == XOR_ARMADA_37XX)
  		return 0;
  
  	/*
  	 * Loop over the cached windows to check, if the requested area
  	 * is already mapped. If this the case, nothing needs to be done
  	 * and we can return.
  	 */
  	for (i = 0; i < WINDOW_COUNT; i++) {
  		if (addr >= xordev->win_start[i] &&
  		    addr <= xordev->win_end[i]) {
  			/* Window is already mapped */
  			return 0;
  		}
  	}
  
  	/*
  	 * The window is not mapped, so we need to create the new mapping
  	 */
  
  	/* If no IO window is found that addr has to be located in SDRAM */
  	ret = mvebu_mbus_get_io_win_info(addr, &size, &target, &attr);
  	if (ret < 0)
  		return 0;
  
  	/*
  	 * Mask the base addr 'addr' according to 'size' read back from the
  	 * MBus window. Otherwise we might end up with an address located
  	 * somewhere in the middle of this area here.
  	 */
  	size -= 1;
  	addr &= ~size;
  
  	/*
  	 * Reading one of both enabled register is enough, as they are always
  	 * programmed to the identical values
  	 */
  	win_enable = readl(base + WINDOW_BAR_ENABLE(0));
  
  	/* Set 'i' to the first free window to write the new values to */
  	i = ffs(~win_enable) - 1;
  	if (i >= WINDOW_COUNT)
  		return -ENOMEM;
  
  	writel((addr & 0xffff0000) | (attr << 8) | target,
  	       base + WINDOW_BASE(i));
  	writel(size & 0xffff0000, base + WINDOW_SIZE(i));
  
  	/* Fill the caching variables for later use */
  	xordev->win_start[i] = addr;
  	xordev->win_end[i] = addr + size;
  
  	win_enable |= (1 << i);
  	win_enable |= 3 << (16 + (2 * i));
  	writel(win_enable, base + WINDOW_BAR_ENABLE(0));
  	writel(win_enable, base + WINDOW_BAR_ENABLE(1));
  
  	return 0;
  }

  static struct dma_async_tx_descriptor *

  mv_xor_prep_dma_xor(struct dma_chan *chan, dma_addr_t dest, dma_addr_t *src,
  		    unsigned int src_cnt, size_t len, unsigned long flags)
  {
  	struct mv_xor_chan *mv_chan = to_mv_xor_chan(chan);

  	struct mv_xor_desc_slot *sw_desc;

  	int ret;

  
  	if (unlikely(len < MV_XOR_MIN_BYTE_COUNT))
  		return NULL;

  	BUG_ON(len > MV_XOR_MAX_BYTE_COUNT);

  	dev_dbg(mv_chan_to_devp(mv_chan),

  		"%s src_cnt: %d len: %zu dest %pad flags: %ld
  ",

  		__func__, src_cnt, len, &dest, flags);

  	/* Check if a new window needs to get added for 'dest' */
  	ret = mv_xor_add_io_win(mv_chan, dest);
  	if (ret)
  		return NULL;

  	sw_desc = mv_chan_alloc_slot(mv_chan);

  	if (sw_desc) {
  		sw_desc->type = DMA_XOR;
  		sw_desc->async_tx.flags = flags;

  		mv_desc_init(sw_desc, dest, len, flags);

  		if (mv_chan->op_in_desc == XOR_MODE_IN_DESC)
  			mv_desc_set_mode(sw_desc);

  		while (src_cnt--) {
  			/* Check if a new window needs to get added for 'src' */
  			ret = mv_xor_add_io_win(mv_chan, src[src_cnt]);
  			if (ret)
  				return NULL;

  			mv_desc_set_src_addr(sw_desc, src_cnt, src[src_cnt]);

  		}

  	}

  	dev_dbg(mv_chan_to_devp(mv_chan),

  		"%s sw_desc %p async_tx %p 
  ",
  		__func__, sw_desc, &sw_desc->async_tx);
  	return sw_desc ? &sw_desc->async_tx : NULL;
  }

  static struct dma_async_tx_descriptor *
  mv_xor_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
  		size_t len, unsigned long flags)
  {
  	/*
  	 * A MEMCPY operation is identical to an XOR operation with only
  	 * a single source address.
  	 */
  	return mv_xor_prep_dma_xor(chan, dest, &src, 1, len, flags);
  }

  static struct dma_async_tx_descriptor *
  mv_xor_prep_dma_interrupt(struct dma_chan *chan, unsigned long flags)
  {
  	struct mv_xor_chan *mv_chan = to_mv_xor_chan(chan);
  	dma_addr_t src, dest;
  	size_t len;
  
  	src = mv_chan->dummy_src_addr;
  	dest = mv_chan->dummy_dst_addr;
  	len = MV_XOR_MIN_BYTE_COUNT;
  
  	/*
  	 * We implement the DMA_INTERRUPT operation as a minimum sized
  	 * XOR operation with a single dummy source address.
  	 */
  	return mv_xor_prep_dma_xor(chan, dest, &src, 1, len, flags);
  }

  static void mv_xor_free_chan_resources(struct dma_chan *chan)
  {
  	struct mv_xor_chan *mv_chan = to_mv_xor_chan(chan);
  	struct mv_xor_desc_slot *iter, *_iter;
  	int in_use_descs = 0;

  	spin_lock_bh(&mv_chan->lock);

  	mv_chan_slot_cleanup(mv_chan);

  	list_for_each_entry_safe(iter, _iter, &mv_chan->chain,

  					node) {

  		in_use_descs++;

  		list_move_tail(&iter->node, &mv_chan->free_slots);

  	}
  	list_for_each_entry_safe(iter, _iter, &mv_chan->completed_slots,

  				 node) {
  		in_use_descs++;
  		list_move_tail(&iter->node, &mv_chan->free_slots);
  	}
  	list_for_each_entry_safe(iter, _iter, &mv_chan->allocated_slots,
  				 node) {

  		in_use_descs++;

  		list_move_tail(&iter->node, &mv_chan->free_slots);

  	}
  	list_for_each_entry_safe_reverse(

  		iter, _iter, &mv_chan->free_slots, node) {
  		list_del(&iter->node);

  		kfree(iter);
  		mv_chan->slots_allocated--;
  	}

  	dev_dbg(mv_chan_to_devp(mv_chan), "%s slots_allocated %d
  ",

  		__func__, mv_chan->slots_allocated);
  	spin_unlock_bh(&mv_chan->lock);
  
  	if (in_use_descs)

  		dev_err(mv_chan_to_devp(mv_chan),

  			"freeing %d in use descriptors!
  ", in_use_descs);
  }
  
  /**

   * mv_xor_status - poll the status of an XOR transaction

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

   * @txstate: XOR transactions state holder (or NULL)

   */

  static enum dma_status mv_xor_status(struct dma_chan *chan,

  					  dma_cookie_t cookie,

  					  struct dma_tx_state *txstate)

  {
  	struct mv_xor_chan *mv_chan = to_mv_xor_chan(chan);

  	enum dma_status ret;

  	ret = dma_cookie_status(chan, cookie, txstate);

  	if (ret == DMA_COMPLETE)

  		return ret;

  
  	spin_lock_bh(&mv_chan->lock);

  	mv_chan_slot_cleanup(mv_chan);

  	spin_unlock_bh(&mv_chan->lock);

  	return dma_cookie_status(chan, cookie, txstate);

  }

  static void mv_chan_dump_regs(struct mv_xor_chan *chan)

  {
  	u32 val;

  	val = readl_relaxed(XOR_CONFIG(chan));

  	dev_err(mv_chan_to_devp(chan), "config       0x%08x
  ", val);

  	val = readl_relaxed(XOR_ACTIVATION(chan));

  	dev_err(mv_chan_to_devp(chan), "activation   0x%08x
  ", val);

  	val = readl_relaxed(XOR_INTR_CAUSE(chan));

  	dev_err(mv_chan_to_devp(chan), "intr cause   0x%08x
  ", val);

  	val = readl_relaxed(XOR_INTR_MASK(chan));

  	dev_err(mv_chan_to_devp(chan), "intr mask    0x%08x
  ", val);

  	val = readl_relaxed(XOR_ERROR_CAUSE(chan));

  	dev_err(mv_chan_to_devp(chan), "error cause  0x%08x
  ", val);

  	val = readl_relaxed(XOR_ERROR_ADDR(chan));

  	dev_err(mv_chan_to_devp(chan), "error addr   0x%08x
  ", val);

  }

  static void mv_chan_err_interrupt_handler(struct mv_xor_chan *chan,
  					  u32 intr_cause)

  {

  	if (intr_cause & XOR_INT_ERR_DECODE) {
  		dev_dbg(mv_chan_to_devp(chan), "ignoring address decode error
  ");
  		return;

  	}

  	dev_err(mv_chan_to_devp(chan), "error on chan %d. intr cause 0x%08x
  ",

  		chan->idx, intr_cause);

  	mv_chan_dump_regs(chan);

  	WARN_ON(1);

  }
  
  static irqreturn_t mv_xor_interrupt_handler(int irq, void *data)
  {
  	struct mv_xor_chan *chan = data;
  	u32 intr_cause = mv_chan_get_intr_cause(chan);

  	dev_dbg(mv_chan_to_devp(chan), "intr cause %x
  ", intr_cause);

  	if (intr_cause & XOR_INTR_ERRORS)

  		mv_chan_err_interrupt_handler(chan, intr_cause);

  
  	tasklet_schedule(&chan->irq_tasklet);

  	mv_chan_clear_eoc_cause(chan);

  
  	return IRQ_HANDLED;
  }
  
  static void mv_xor_issue_pending(struct dma_chan *chan)
  {
  	struct mv_xor_chan *mv_chan = to_mv_xor_chan(chan);
  
  	if (mv_chan->pending >= MV_XOR_THRESHOLD) {
  		mv_chan->pending = 0;
  		mv_chan_activate(mv_chan);
  	}
  }
  
  /*
   * Perform a transaction to verify the HW works.
   */

  static int mv_chan_memcpy_self_test(struct mv_xor_chan *mv_chan)

  {

  	int i, ret;

  	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;

  	struct dmaengine_unmap_data *unmap;

  	int err = 0;

  	src = kmalloc(sizeof(u8) * PAGE_SIZE, GFP_KERNEL);

  	if (!src)
  		return -ENOMEM;

  	dest = kzalloc(sizeof(u8) * PAGE_SIZE, GFP_KERNEL);

  	if (!dest) {
  		kfree(src);
  		return -ENOMEM;
  	}
  
  	/* Fill in src buffer */

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

  		((u8 *) src)[i] = (u8)i;

  	dma_chan = &mv_chan->dmachan;

  	if (mv_xor_alloc_chan_resources(dma_chan) < 1) {

  		err = -ENODEV;
  		goto out;
  	}

  	unmap = dmaengine_get_unmap_data(dma_chan->device->dev, 2, GFP_KERNEL);
  	if (!unmap) {
  		err = -ENOMEM;
  		goto free_resources;
  	}

  	src_dma = dma_map_page(dma_chan->device->dev, virt_to_page(src),

  			       offset_in_page(src), PAGE_SIZE,

  			       DMA_TO_DEVICE);

  	unmap->addr[0] = src_dma;

  	ret = dma_mapping_error(dma_chan->device->dev, src_dma);
  	if (ret) {
  		err = -ENOMEM;
  		goto free_resources;
  	}
  	unmap->to_cnt = 1;

  	dest_dma = dma_map_page(dma_chan->device->dev, virt_to_page(dest),

  				offset_in_page(dest), PAGE_SIZE,

  				DMA_FROM_DEVICE);

  	unmap->addr[1] = dest_dma;

  	ret = dma_mapping_error(dma_chan->device->dev, dest_dma);
  	if (ret) {
  		err = -ENOMEM;
  		goto free_resources;
  	}
  	unmap->from_cnt = 1;

  	unmap->len = PAGE_SIZE;

  
  	tx = mv_xor_prep_dma_memcpy(dma_chan, dest_dma, src_dma,

  				    PAGE_SIZE, 0);

  	if (!tx) {
  		dev_err(dma_chan->device->dev,
  			"Self-test cannot prepare operation, disabling
  ");
  		err = -ENODEV;
  		goto free_resources;
  	}

  	cookie = mv_xor_tx_submit(tx);

  	if (dma_submit_error(cookie)) {
  		dev_err(dma_chan->device->dev,
  			"Self-test submit error, disabling
  ");
  		err = -ENODEV;
  		goto free_resources;
  	}

  	mv_xor_issue_pending(dma_chan);
  	async_tx_ack(tx);
  	msleep(1);

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

  	    DMA_COMPLETE) {

  		dev_err(dma_chan->device->dev,
  			"Self-test copy timed out, disabling
  ");

  		err = -ENODEV;
  		goto free_resources;
  	}

  	dma_sync_single_for_cpu(dma_chan->device->dev, dest_dma,

  				PAGE_SIZE, DMA_FROM_DEVICE);
  	if (memcmp(src, dest, PAGE_SIZE)) {

  		dev_err(dma_chan->device->dev,
  			"Self-test copy failed compare, disabling
  ");

  		err = -ENODEV;
  		goto free_resources;
  	}
  
  free_resources:

  	dmaengine_unmap_put(unmap);

  	mv_xor_free_chan_resources(dma_chan);
  out:
  	kfree(src);
  	kfree(dest);
  	return err;
  }
  
  #define MV_XOR_NUM_SRC_TEST 4 /* must be <= 15 */

  static int

  mv_chan_xor_self_test(struct mv_xor_chan *mv_chan)

  {

  	int i, src_idx, ret;

  	struct page *dest;
  	struct page *xor_srcs[MV_XOR_NUM_SRC_TEST];
  	dma_addr_t dma_srcs[MV_XOR_NUM_SRC_TEST];
  	dma_addr_t dest_dma;
  	struct dma_async_tx_descriptor *tx;

  	struct dmaengine_unmap_data *unmap;

  	struct dma_chan *dma_chan;
  	dma_cookie_t cookie;
  	u8 cmp_byte = 0;
  	u32 cmp_word;
  	int err = 0;

  	int src_count = MV_XOR_NUM_SRC_TEST;

  	for (src_idx = 0; src_idx < src_count; 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 < src_count; 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 < src_count; 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 = &mv_chan->dmachan;

  	if (mv_xor_alloc_chan_resources(dma_chan) < 1) {

  		err = -ENODEV;
  		goto out;
  	}

  	unmap = dmaengine_get_unmap_data(dma_chan->device->dev, src_count + 1,
  					 GFP_KERNEL);
  	if (!unmap) {
  		err = -ENOMEM;
  		goto free_resources;
  	}

  	/* test xor */

  	for (i = 0; i < src_count; i++) {
  		unmap->addr[i] = dma_map_page(dma_chan->device->dev, xor_srcs[i],
  					      0, PAGE_SIZE, DMA_TO_DEVICE);
  		dma_srcs[i] = unmap->addr[i];

  		ret = dma_mapping_error(dma_chan->device->dev, unmap->addr[i]);
  		if (ret) {
  			err = -ENOMEM;
  			goto free_resources;
  		}

  		unmap->to_cnt++;
  	}

  	unmap->addr[src_count] = dma_map_page(dma_chan->device->dev, dest, 0, PAGE_SIZE,
  				      DMA_FROM_DEVICE);
  	dest_dma = unmap->addr[src_count];

  	ret = dma_mapping_error(dma_chan->device->dev, unmap->addr[src_count]);
  	if (ret) {
  		err = -ENOMEM;
  		goto free_resources;
  	}

  	unmap->from_cnt = 1;
  	unmap->len = PAGE_SIZE;

  
  	tx = mv_xor_prep_dma_xor(dma_chan, dest_dma, dma_srcs,

  				 src_count, PAGE_SIZE, 0);

  	if (!tx) {
  		dev_err(dma_chan->device->dev,
  			"Self-test cannot prepare operation, disabling
  ");
  		err = -ENODEV;
  		goto free_resources;
  	}

  
  	cookie = mv_xor_tx_submit(tx);

  	if (dma_submit_error(cookie)) {
  		dev_err(dma_chan->device->dev,
  			"Self-test submit error, disabling
  ");
  		err = -ENODEV;
  		goto free_resources;
  	}

  	mv_xor_issue_pending(dma_chan);
  	async_tx_ack(tx);
  	msleep(8);

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

  	    DMA_COMPLETE) {

  		dev_err(dma_chan->device->dev,
  			"Self-test xor timed out, disabling
  ");

  		err = -ENODEV;
  		goto free_resources;
  	}

  	dma_sync_single_for_cpu(dma_chan->device->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_err(dma_chan->device->dev,

  				"Self-test xor failed compare, disabling. index %d, data %x, expected %x
  ",
  				i, ptr[i], cmp_word);

  			err = -ENODEV;
  			goto free_resources;
  		}
  	}
  
  free_resources:

  	dmaengine_unmap_put(unmap);

  	mv_xor_free_chan_resources(dma_chan);
  out:

  	src_idx = src_count;

  	while (src_idx--)
  		__free_page(xor_srcs[src_idx]);
  	__free_page(dest);
  	return err;
  }

  static int mv_xor_channel_remove(struct mv_xor_chan *mv_chan)

  {

  	struct dma_chan *chan, *_chan;

  	struct device *dev = mv_chan->dmadev.dev;

  	dma_async_device_unregister(&mv_chan->dmadev);

  	dma_free_coherent(dev, MV_XOR_POOL_SIZE,

  			  mv_chan->dma_desc_pool_virt, mv_chan->dma_desc_pool);

  	dma_unmap_single(dev, mv_chan->dummy_src_addr,
  			 MV_XOR_MIN_BYTE_COUNT, DMA_FROM_DEVICE);
  	dma_unmap_single(dev, mv_chan->dummy_dst_addr,
  			 MV_XOR_MIN_BYTE_COUNT, DMA_TO_DEVICE);

  	list_for_each_entry_safe(chan, _chan, &mv_chan->dmadev.channels,

  				 device_node) {

  		list_del(&chan->device_node);
  	}

  	free_irq(mv_chan->irq, mv_chan);

  	return 0;
  }

  static struct mv_xor_chan *

  mv_xor_channel_add(struct mv_xor_device *xordev,

  		   struct platform_device *pdev,

  		   int idx, dma_cap_mask_t cap_mask, int irq)

  {
  	int ret = 0;

  	struct mv_xor_chan *mv_chan;
  	struct dma_device *dma_dev;

  	mv_chan = devm_kzalloc(&pdev->dev, sizeof(*mv_chan), GFP_KERNEL);

  	if (!mv_chan)
  		return ERR_PTR(-ENOMEM);

  	mv_chan->idx = idx;

  	mv_chan->irq = irq;

  	if (xordev->xor_type == XOR_ORION)
  		mv_chan->op_in_desc = XOR_MODE_IN_REG;
  	else
  		mv_chan->op_in_desc = XOR_MODE_IN_DESC;

  	dma_dev = &mv_chan->dmadev;

  	mv_chan->xordev = xordev;

  	/*
  	 * These source and destination dummy buffers are used to implement
  	 * a DMA_INTERRUPT operation as a minimum-sized XOR operation.
  	 * Hence, we only need to map the buffers at initialization-time.
  	 */
  	mv_chan->dummy_src_addr = dma_map_single(dma_dev->dev,
  		mv_chan->dummy_src, MV_XOR_MIN_BYTE_COUNT, DMA_FROM_DEVICE);
  	mv_chan->dummy_dst_addr = dma_map_single(dma_dev->dev,
  		mv_chan->dummy_dst, MV_XOR_MIN_BYTE_COUNT, DMA_TO_DEVICE);

  	/* allocate coherent memory for hardware descriptors
  	 * note: writecombine gives slightly better performance, but
  	 * requires that we explicitly flush the writes
  	 */

  	mv_chan->dma_desc_pool_virt =

  	  dma_alloc_wc(&pdev->dev, MV_XOR_POOL_SIZE, &mv_chan->dma_desc_pool,
  		       GFP_KERNEL);

  	if (!mv_chan->dma_desc_pool_virt)

  		return ERR_PTR(-ENOMEM);

  
  	/* discover transaction capabilites from the platform data */

  	dma_dev->cap_mask = cap_mask;

  
  	INIT_LIST_HEAD(&dma_dev->channels);
  
  	/* set base routines */
  	dma_dev->device_alloc_chan_resources = mv_xor_alloc_chan_resources;
  	dma_dev->device_free_chan_resources = mv_xor_free_chan_resources;

  	dma_dev->device_tx_status = mv_xor_status;

  	dma_dev->device_issue_pending = mv_xor_issue_pending;
  	dma_dev->dev = &pdev->dev;
  
  	/* set prep routines based on capability */

  	if (dma_has_cap(DMA_INTERRUPT, dma_dev->cap_mask))
  		dma_dev->device_prep_dma_interrupt = mv_xor_prep_dma_interrupt;

  	if (dma_has_cap(DMA_MEMCPY, dma_dev->cap_mask))
  		dma_dev->device_prep_dma_memcpy = mv_xor_prep_dma_memcpy;

  	if (dma_has_cap(DMA_XOR, dma_dev->cap_mask)) {

  		dma_dev->max_xor = 8;

  		dma_dev->device_prep_dma_xor = mv_xor_prep_dma_xor;
  	}

  	mv_chan->mmr_base = xordev->xor_base;

  	mv_chan->mmr_high_base = xordev->xor_high_base;

  	tasklet_init(&mv_chan->irq_tasklet, mv_xor_tasklet, (unsigned long)
  		     mv_chan);
  
  	/* clear errors before enabling interrupts */

  	mv_chan_clear_err_status(mv_chan);

  	ret = request_irq(mv_chan->irq, mv_xor_interrupt_handler,
  			  0, dev_name(&pdev->dev), mv_chan);

  	if (ret)
  		goto err_free_dma;
  
  	mv_chan_unmask_interrupts(mv_chan);

  	if (mv_chan->op_in_desc == XOR_MODE_IN_DESC)

  		mv_chan_set_mode(mv_chan, XOR_OPERATION_MODE_IN_DESC);

  	else

  		mv_chan_set_mode(mv_chan, XOR_OPERATION_MODE_XOR);

  
  	spin_lock_init(&mv_chan->lock);
  	INIT_LIST_HEAD(&mv_chan->chain);
  	INIT_LIST_HEAD(&mv_chan->completed_slots);

  	INIT_LIST_HEAD(&mv_chan->free_slots);
  	INIT_LIST_HEAD(&mv_chan->allocated_slots);

  	mv_chan->dmachan.device = dma_dev;
  	dma_cookie_init(&mv_chan->dmachan);

  	list_add_tail(&mv_chan->dmachan.device_node, &dma_dev->channels);

  
  	if (dma_has_cap(DMA_MEMCPY, dma_dev->cap_mask)) {

  		ret = mv_chan_memcpy_self_test(mv_chan);

  		dev_dbg(&pdev->dev, "memcpy self test returned %d
  ", ret);
  		if (ret)

  			goto err_free_irq;

  	}
  
  	if (dma_has_cap(DMA_XOR, dma_dev->cap_mask)) {

  		ret = mv_chan_xor_self_test(mv_chan);

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

  			goto err_free_irq;

  	}

  	dev_info(&pdev->dev, "Marvell XOR (%s): ( %s%s%s)
  ",

  		 mv_chan->op_in_desc ? "Descriptor Mode" : "Registers Mode",

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

  		 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);

  	return mv_chan;

  err_free_irq:
  	free_irq(mv_chan->irq, mv_chan);

  err_free_dma:

  	dma_free_coherent(&pdev->dev, MV_XOR_POOL_SIZE,

  			  mv_chan->dma_desc_pool_virt, mv_chan->dma_desc_pool);

  	return ERR_PTR(ret);

  }
  
  static void

  mv_xor_conf_mbus_windows(struct mv_xor_device *xordev,

  			 const struct mbus_dram_target_info *dram)

  {

  	void __iomem *base = xordev->xor_high_base;

  	u32 win_enable = 0;
  	int i;
  
  	for (i = 0; i < 8; i++) {
  		writel(0, base + WINDOW_BASE(i));
  		writel(0, base + WINDOW_SIZE(i));
  		if (i < 4)
  			writel(0, base + WINDOW_REMAP_HIGH(i));
  	}
  
  	for (i = 0; i < dram->num_cs; i++) {

  		const struct mbus_dram_window *cs = dram->cs + i;

  
  		writel((cs->base & 0xffff0000) |
  		       (cs->mbus_attr << 8) |
  		       dram->mbus_dram_target_id, base + WINDOW_BASE(i));
  		writel((cs->size - 1) & 0xffff0000, base + WINDOW_SIZE(i));

  		/* Fill the caching variables for later use */
  		xordev->win_start[i] = cs->base;
  		xordev->win_end[i] = cs->base + cs->size - 1;

  		win_enable |= (1 << i);
  		win_enable |= 3 << (16 + (2 * i));
  	}
  
  	writel(win_enable, base + WINDOW_BAR_ENABLE(0));
  	writel(win_enable, base + WINDOW_BAR_ENABLE(1));

  	writel(0, base + WINDOW_OVERRIDE_CTRL(0));
  	writel(0, base + WINDOW_OVERRIDE_CTRL(1));

  }

  static void
  mv_xor_conf_mbus_windows_a3700(struct mv_xor_device *xordev)
  {
  	void __iomem *base = xordev->xor_high_base;
  	u32 win_enable = 0;
  	int i;
  
  	for (i = 0; i < 8; i++) {
  		writel(0, base + WINDOW_BASE(i));
  		writel(0, base + WINDOW_SIZE(i));
  		if (i < 4)
  			writel(0, base + WINDOW_REMAP_HIGH(i));
  	}
  	/*
  	 * For Armada3700 open default 4GB Mbus window. The dram
  	 * related configuration are done at AXIS level.
  	 */
  	writel(0xffff0000, base + WINDOW_SIZE(0));
  	win_enable |= 1;
  	win_enable |= 3 << 16;
  
  	writel(win_enable, base + WINDOW_BAR_ENABLE(0));
  	writel(win_enable, base + WINDOW_BAR_ENABLE(1));
  	writel(0, base + WINDOW_OVERRIDE_CTRL(0));
  	writel(0, base + WINDOW_OVERRIDE_CTRL(1));
  }

  /*
   * Since this XOR driver is basically used only for RAID5, we don't
   * need to care about synchronizing ->suspend with DMA activity,
   * because the DMA engine will naturally be quiet due to the block
   * devices being suspended.
   */
  static int mv_xor_suspend(struct platform_device *pdev, pm_message_t state)
  {
  	struct mv_xor_device *xordev = platform_get_drvdata(pdev);
  	int i;
  
  	for (i = 0; i < MV_XOR_MAX_CHANNELS; i++) {
  		struct mv_xor_chan *mv_chan = xordev->channels[i];
  
  		if (!mv_chan)
  			continue;
  
  		mv_chan->saved_config_reg =
  			readl_relaxed(XOR_CONFIG(mv_chan));
  		mv_chan->saved_int_mask_reg =
  			readl_relaxed(XOR_INTR_MASK(mv_chan));
  	}
  
  	return 0;
  }
  
  static int mv_xor_resume(struct platform_device *dev)
  {
  	struct mv_xor_device *xordev = platform_get_drvdata(dev);
  	const struct mbus_dram_target_info *dram;
  	int i;
  
  	for (i = 0; i < MV_XOR_MAX_CHANNELS; i++) {
  		struct mv_xor_chan *mv_chan = xordev->channels[i];
  
  		if (!mv_chan)
  			continue;
  
  		writel_relaxed(mv_chan->saved_config_reg,
  			       XOR_CONFIG(mv_chan));
  		writel_relaxed(mv_chan->saved_int_mask_reg,
  			       XOR_INTR_MASK(mv_chan));
  	}

  	if (xordev->xor_type == XOR_ARMADA_37XX) {
  		mv_xor_conf_mbus_windows_a3700(xordev);
  		return 0;
  	}

  	dram = mv_mbus_dram_info();
  	if (dram)
  		mv_xor_conf_mbus_windows(xordev, dram);
  
  	return 0;
  }

  static const struct of_device_id mv_xor_dt_ids[] = {

  	{ .compatible = "marvell,orion-xor", .data = (void *)XOR_ORION },
  	{ .compatible = "marvell,armada-380-xor", .data = (void *)XOR_ARMADA_38X },

  	{ .compatible = "marvell,armada-3700-xor", .data = (void *)XOR_ARMADA_37XX },

  	{},
  };

  static unsigned int mv_xor_engine_count;

  static int mv_xor_probe(struct platform_device *pdev)

  {

  	const struct mbus_dram_target_info *dram;

  	struct mv_xor_device *xordev;

  	struct mv_xor_platform_data *pdata = dev_get_platdata(&pdev->dev);

  	struct resource *res;

  	unsigned int max_engines, max_channels;

  	int i, ret;

  	dev_notice(&pdev->dev, "Marvell shared XOR driver
  ");

  	xordev = devm_kzalloc(&pdev->dev, sizeof(*xordev), GFP_KERNEL);
  	if (!xordev)

  		return -ENOMEM;
  
  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	if (!res)
  		return -ENODEV;

  	xordev->xor_base = devm_ioremap(&pdev->dev, res->start,
  					resource_size(res));
  	if (!xordev->xor_base)

  		return -EBUSY;
  
  	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
  	if (!res)
  		return -ENODEV;

  	xordev->xor_high_base = devm_ioremap(&pdev->dev, res->start,
  					     resource_size(res));
  	if (!xordev->xor_high_base)

  		return -EBUSY;

  	platform_set_drvdata(pdev, xordev);

  
  	/*
  	 * We need to know which type of XOR device we use before
  	 * setting up. In non-dt case it can only be the legacy one.
  	 */
  	xordev->xor_type = XOR_ORION;
  	if (pdev->dev.of_node) {
  		const struct of_device_id *of_id =
  			of_match_device(mv_xor_dt_ids,
  					&pdev->dev);
  
  		xordev->xor_type = (uintptr_t)of_id->data;
  	}

  	/*
  	 * (Re-)program MBUS remapping windows if we are asked to.
  	 */

  	if (xordev->xor_type == XOR_ARMADA_37XX) {
  		mv_xor_conf_mbus_windows_a3700(xordev);
  	} else {
  		dram = mv_mbus_dram_info();
  		if (dram)
  			mv_xor_conf_mbus_windows(xordev, dram);
  	}

  	/* Not all platforms can gate the clock, so it is not
  	 * an error if the clock does not exists.
  	 */

  	xordev->clk = clk_get(&pdev->dev, NULL);
  	if (!IS_ERR(xordev->clk))
  		clk_prepare_enable(xordev->clk);

  	/*
  	 * We don't want to have more than one channel per CPU in
  	 * order for async_tx to perform well. So we limit the number
  	 * of engines and channels so that we take into account this
  	 * constraint. Note that we also want to use channels from

  	 * separate engines when possible.  For dual-CPU Armada 3700
  	 * SoC with single XOR engine allow using its both channels.

  	 */
  	max_engines = num_present_cpus();

  	if (xordev->xor_type == XOR_ARMADA_37XX)
  		max_channels =	num_present_cpus();
  	else
  		max_channels = min_t(unsigned int,
  				     MV_XOR_MAX_CHANNELS,
  				     DIV_ROUND_UP(num_present_cpus(), 2));

  
  	if (mv_xor_engine_count >= max_engines)
  		return 0;

  	if (pdev->dev.of_node) {
  		struct device_node *np;
  		int i = 0;
  
  		for_each_child_of_node(pdev->dev.of_node, np) {

  			struct mv_xor_chan *chan;

  			dma_cap_mask_t cap_mask;
  			int irq;

  			if (i >= max_channels)
  				continue;

  			dma_cap_zero(cap_mask);

  			dma_cap_set(DMA_MEMCPY, cap_mask);
  			dma_cap_set(DMA_XOR, cap_mask);
  			dma_cap_set(DMA_INTERRUPT, cap_mask);

  
  			irq = irq_of_parse_and_map(np, 0);

  			if (!irq) {
  				ret = -ENODEV;

  				goto err_channel_add;
  			}

  			chan = mv_xor_channel_add(xordev, pdev, i,

  						  cap_mask, irq);

  			if (IS_ERR(chan)) {
  				ret = PTR_ERR(chan);

  				irq_dispose_mapping(irq);
  				goto err_channel_add;
  			}

  			xordev->channels[i] = chan;

  			i++;
  		}
  	} else if (pdata && pdata->channels) {

  		for (i = 0; i < max_channels; i++) {

  			struct mv_xor_channel_data *cd;

  			struct mv_xor_chan *chan;

  			int irq;
  
  			cd = &pdata->channels[i];

  			irq = platform_get_irq(pdev, i);
  			if (irq < 0) {
  				ret = irq;
  				goto err_channel_add;
  			}

  			chan = mv_xor_channel_add(xordev, pdev, i,

  						  cd->cap_mask, irq);

  			if (IS_ERR(chan)) {
  				ret = PTR_ERR(chan);

  				goto err_channel_add;
  			}

  
  			xordev->channels[i] = chan;

  		}
  	}

  	return 0;

  
  err_channel_add:
  	for (i = 0; i < MV_XOR_MAX_CHANNELS; i++)

  		if (xordev->channels[i]) {

  			mv_xor_channel_remove(xordev->channels[i]);

  			if (pdev->dev.of_node)
  				irq_dispose_mapping(xordev->channels[i]->irq);

  		}

  	if (!IS_ERR(xordev->clk)) {
  		clk_disable_unprepare(xordev->clk);
  		clk_put(xordev->clk);
  	}

  	return ret;

  }

  static struct platform_driver mv_xor_driver = {
  	.probe		= mv_xor_probe,

  	.suspend        = mv_xor_suspend,
  	.resume         = mv_xor_resume,

  	.driver		= {

  		.name	        = MV_XOR_NAME,
  		.of_match_table = of_match_ptr(mv_xor_dt_ids),

  	},
  };

  builtin_platform_driver(mv_xor_driver);

  /*

  MODULE_AUTHOR("Saeed Bishara <saeed@marvell.com>");
  MODULE_DESCRIPTION("DMA engine driver for Marvell's XOR engine");
  MODULE_LICENSE("GPL");

  */