// SPDX-License-Identifier: GPL-2.0-or-later

  /*
   * Freescale MPC85xx, MPC83xx DMA Engine support
   *

   * Copyright (C) 2007-2010 Freescale Semiconductor, Inc. All rights reserved.

   *
   * Author:
   *   Zhang Wei <wei.zhang@freescale.com>, Jul 2007
   *   Ebony Zhu <ebony.zhu@freescale.com>, May 2007
   *
   * Description:
   *   DMA engine driver for Freescale MPC8540 DMA controller, which is
   *   also fit for MPC8560, MPC8555, MPC8548, MPC8641, and etc.

   *   The support for MPC8349 DMA controller is also added.

   *

   * This driver instructs the DMA controller to issue the PCI Read Multiple
   * command for PCI read operations, instead of using the default PCI Read Line
   * command. Please be aware that this setting may result in read pre-fetching
   * on some platforms.

   */
  
  #include <linux/init.h>
  #include <linux/module.h>
  #include <linux/pci.h>

  #include <linux/slab.h>

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

  #include <linux/of_address.h>
  #include <linux/of_irq.h>

  #include <linux/of_platform.h>

  #include <linux/fsldma.h>

  #include "dmaengine.h"

  #include "fsldma.h"

  #define chan_dbg(chan, fmt, arg...)					\
  	dev_dbg(chan->dev, "%s: " fmt, chan->name, ##arg)
  #define chan_err(chan, fmt, arg...)					\
  	dev_err(chan->dev, "%s: " fmt, chan->name, ##arg)

  static const char msg_ld_oom[] = "No free memory for link descriptor";

  /*
   * Register Helpers
   */

  static void set_sr(struct fsldma_chan *chan, u32 val)

  {

  	FSL_DMA_OUT(chan, &chan->regs->sr, val, 32);

  }

  static u32 get_sr(struct fsldma_chan *chan)

  {

  	return FSL_DMA_IN(chan, &chan->regs->sr, 32);

  }

  static void set_mr(struct fsldma_chan *chan, u32 val)
  {

  	FSL_DMA_OUT(chan, &chan->regs->mr, val, 32);

  }
  
  static u32 get_mr(struct fsldma_chan *chan)
  {

  	return FSL_DMA_IN(chan, &chan->regs->mr, 32);

  }

  static void set_cdar(struct fsldma_chan *chan, dma_addr_t addr)
  {

  	FSL_DMA_OUT(chan, &chan->regs->cdar, addr | FSL_DMA_SNEN, 64);

  }
  
  static dma_addr_t get_cdar(struct fsldma_chan *chan)
  {

  	return FSL_DMA_IN(chan, &chan->regs->cdar, 64) & ~FSL_DMA_SNEN;

  }

  static void set_bcr(struct fsldma_chan *chan, u32 val)
  {

  	FSL_DMA_OUT(chan, &chan->regs->bcr, val, 32);

  }

  static u32 get_bcr(struct fsldma_chan *chan)
  {

  	return FSL_DMA_IN(chan, &chan->regs->bcr, 32);

  }
  
  /*
   * Descriptor Helpers
   */

  static void set_desc_cnt(struct fsldma_chan *chan,

  				struct fsl_dma_ld_hw *hw, u32 count)
  {

  	hw->count = CPU_TO_DMA(chan, count, 32);

  }

  static void set_desc_src(struct fsldma_chan *chan,

  			 struct fsl_dma_ld_hw *hw, dma_addr_t src)

  {
  	u64 snoop_bits;

  	snoop_bits = ((chan->feature & FSL_DMA_IP_MASK) == FSL_DMA_IP_85XX)

  		? ((u64)FSL_DMA_SATR_SREADTYPE_SNOOP_READ << 32) : 0;

  	hw->src_addr = CPU_TO_DMA(chan, snoop_bits | src, 64);

  }

  static void set_desc_dst(struct fsldma_chan *chan,

  			 struct fsl_dma_ld_hw *hw, dma_addr_t dst)

  {
  	u64 snoop_bits;

  	snoop_bits = ((chan->feature & FSL_DMA_IP_MASK) == FSL_DMA_IP_85XX)

  		? ((u64)FSL_DMA_DATR_DWRITETYPE_SNOOP_WRITE << 32) : 0;

  	hw->dst_addr = CPU_TO_DMA(chan, snoop_bits | dst, 64);

  }

  static void set_desc_next(struct fsldma_chan *chan,

  			  struct fsl_dma_ld_hw *hw, dma_addr_t next)

  {
  	u64 snoop_bits;

  	snoop_bits = ((chan->feature & FSL_DMA_IP_MASK) == FSL_DMA_IP_83XX)

  		? FSL_DMA_SNEN : 0;

  	hw->next_ln_addr = CPU_TO_DMA(chan, snoop_bits | next, 64);

  }

  static void set_ld_eol(struct fsldma_chan *chan, struct fsl_desc_sw *desc)

  {

  	u64 snoop_bits;

  	snoop_bits = ((chan->feature & FSL_DMA_IP_MASK) == FSL_DMA_IP_83XX)
  		? FSL_DMA_SNEN : 0;

  	desc->hw.next_ln_addr = CPU_TO_DMA(chan,
  		DMA_TO_CPU(chan, desc->hw.next_ln_addr, 64) | FSL_DMA_EOL
  			| snoop_bits, 64);

  }

  /*
   * DMA Engine Hardware Control Helpers
   */
  
  static void dma_init(struct fsldma_chan *chan)

  {

  	/* Reset the channel */

  	set_mr(chan, 0);

  
  	switch (chan->feature & FSL_DMA_IP_MASK) {
  	case FSL_DMA_IP_85XX:
  		/* Set the channel to below modes:
  		 * EIE - Error interrupt enable

  		 * EOLNIE - End of links interrupt enable
  		 * BWC - Bandwidth sharing among channels
  		 */

  		set_mr(chan, FSL_DMA_MR_BWC | FSL_DMA_MR_EIE
  			| FSL_DMA_MR_EOLNIE);

  		break;
  	case FSL_DMA_IP_83XX:
  		/* Set the channel to below modes:
  		 * EOTIE - End-of-transfer interrupt enable
  		 * PRC_RM - PCI read multiple
  		 */

  		set_mr(chan, FSL_DMA_MR_EOTIE | FSL_DMA_MR_PRC_RM);

  		break;
  	}

  }

  static int dma_is_idle(struct fsldma_chan *chan)

  {

  	u32 sr = get_sr(chan);

  	return (!(sr & FSL_DMA_SR_CB)) || (sr & FSL_DMA_SR_CH);
  }

  /*
   * Start the DMA controller
   *
   * Preconditions:
   * - the CDAR register must point to the start descriptor
   * - the MRn[CS] bit must be cleared
   */

  static void dma_start(struct fsldma_chan *chan)

  {

  	u32 mode;

  	mode = get_mr(chan);

  	if (chan->feature & FSL_DMA_CHAN_PAUSE_EXT) {

  		set_bcr(chan, 0);

  		mode |= FSL_DMA_MR_EMP_EN;
  	} else {
  		mode &= ~FSL_DMA_MR_EMP_EN;

  	}

  	if (chan->feature & FSL_DMA_CHAN_START_EXT) {

  		mode |= FSL_DMA_MR_EMS_EN;

  	} else {
  		mode &= ~FSL_DMA_MR_EMS_EN;

  		mode |= FSL_DMA_MR_CS;

  	}

  	set_mr(chan, mode);

  }

  static void dma_halt(struct fsldma_chan *chan)

  {

  	u32 mode;

  	int i;

  	/* read the mode register */

  	mode = get_mr(chan);

  	/*
  	 * The 85xx controller supports channel abort, which will stop
  	 * the current transfer. On 83xx, this bit is the transfer error
  	 * mask bit, which should not be changed.
  	 */
  	if ((chan->feature & FSL_DMA_IP_MASK) == FSL_DMA_IP_85XX) {
  		mode |= FSL_DMA_MR_CA;

  		set_mr(chan, mode);

  
  		mode &= ~FSL_DMA_MR_CA;
  	}
  
  	/* stop the DMA controller */
  	mode &= ~(FSL_DMA_MR_CS | FSL_DMA_MR_EMS_EN);

  	set_mr(chan, mode);

  	/* wait for the DMA controller to become idle */

  	for (i = 0; i < 100; i++) {

  		if (dma_is_idle(chan))

  			return;

  		udelay(10);

  	}

  	if (!dma_is_idle(chan))

  		chan_err(chan, "DMA halt timeout!
  ");

  }

  /**
   * fsl_chan_set_src_loop_size - Set source address hold transfer size

   * @chan : Freescale DMA channel

   * @size     : Address loop size, 0 for disable loop
   *
   * The set source address hold transfer size. The source
   * address hold or loop transfer size is when the DMA transfer
   * data from source address (SA), if the loop size is 4, the DMA will
   * read data from SA, SA + 1, SA + 2, SA + 3, then loop back to SA,
   * SA + 1 ... and so on.
   */

  static void fsl_chan_set_src_loop_size(struct fsldma_chan *chan, int size)

  {

  	u32 mode;

  	mode = get_mr(chan);

  	switch (size) {
  	case 0:

  		mode &= ~FSL_DMA_MR_SAHE;

  		break;
  	case 1:
  	case 2:
  	case 4:
  	case 8:

  		mode &= ~FSL_DMA_MR_SAHTS_MASK;

  		mode |= FSL_DMA_MR_SAHE | (__ilog2(size) << 14);

  		break;
  	}

  	set_mr(chan, mode);

  }
  
  /**

   * fsl_chan_set_dst_loop_size - Set destination address hold transfer size

   * @chan : Freescale DMA channel

   * @size     : Address loop size, 0 for disable loop
   *
   * The set destination address hold transfer size. The destination
   * address hold or loop transfer size is when the DMA transfer
   * data to destination address (TA), if the loop size is 4, the DMA will
   * write data to TA, TA + 1, TA + 2, TA + 3, then loop back to TA,
   * TA + 1 ... and so on.
   */

  static void fsl_chan_set_dst_loop_size(struct fsldma_chan *chan, int size)

  {

  	u32 mode;

  	mode = get_mr(chan);

  	switch (size) {
  	case 0:

  		mode &= ~FSL_DMA_MR_DAHE;

  		break;
  	case 1:
  	case 2:
  	case 4:
  	case 8:

  		mode &= ~FSL_DMA_MR_DAHTS_MASK;

  		mode |= FSL_DMA_MR_DAHE | (__ilog2(size) << 16);

  		break;
  	}

  	set_mr(chan, mode);

  }
  
  /**

   * fsl_chan_set_request_count - Set DMA Request Count for external control

   * @chan : Freescale DMA channel

   * @size     : Number of bytes to transfer in a single request
   *
   * The Freescale DMA channel can be controlled by the external signal DREQ#.
   * The DMA request count is how many bytes are allowed to transfer before
   * pausing the channel, after which a new assertion of DREQ# resumes channel
   * operation.

   *

   * A size of 0 disables external pause control. The maximum size is 1024.

   */

  static void fsl_chan_set_request_count(struct fsldma_chan *chan, int size)

  {

  	u32 mode;

  	BUG_ON(size > 1024);

  	mode = get_mr(chan);

  	mode &= ~FSL_DMA_MR_BWC_MASK;
  	mode |= (__ilog2(size) << 24) & FSL_DMA_MR_BWC_MASK;

  	set_mr(chan, mode);

  }

  /**
   * fsl_chan_toggle_ext_pause - Toggle channel external pause status

   * @chan : Freescale DMA channel

   * @enable   : 0 is disabled, 1 is enabled.
   *
   * The Freescale DMA channel can be controlled by the external signal DREQ#.
   * The DMA Request Count feature should be used in addition to this feature
   * to set the number of bytes to transfer before pausing the channel.
   */

  static void fsl_chan_toggle_ext_pause(struct fsldma_chan *chan, int enable)

  {
  	if (enable)

  		chan->feature |= FSL_DMA_CHAN_PAUSE_EXT;

  	else

  		chan->feature &= ~FSL_DMA_CHAN_PAUSE_EXT;

  }
  
  /**
   * fsl_chan_toggle_ext_start - Toggle channel external start status

   * @chan : Freescale DMA channel

   * @enable   : 0 is disabled, 1 is enabled.
   *
   * If enable the external start, the channel can be started by an
   * external DMA start pin. So the dma_start() does not start the
   * transfer immediately. The DMA channel will wait for the
   * control pin asserted.
   */

  static void fsl_chan_toggle_ext_start(struct fsldma_chan *chan, int enable)

  {
  	if (enable)

  		chan->feature |= FSL_DMA_CHAN_START_EXT;

  	else

  		chan->feature &= ~FSL_DMA_CHAN_START_EXT;

  }

  int fsl_dma_external_start(struct dma_chan *dchan, int enable)
  {
  	struct fsldma_chan *chan;
  
  	if (!dchan)
  		return -EINVAL;
  
  	chan = to_fsl_chan(dchan);
  
  	fsl_chan_toggle_ext_start(chan, enable);
  	return 0;
  }
  EXPORT_SYMBOL_GPL(fsl_dma_external_start);

  static void append_ld_queue(struct fsldma_chan *chan, struct fsl_desc_sw *desc)

  {
  	struct fsl_desc_sw *tail = to_fsl_desc(chan->ld_pending.prev);
  
  	if (list_empty(&chan->ld_pending))
  		goto out_splice;
  
  	/*
  	 * Add the hardware descriptor to the chain of hardware descriptors
  	 * that already exists in memory.
  	 *
  	 * This will un-set the EOL bit of the existing transaction, and the
  	 * last link in this transaction will become the EOL descriptor.
  	 */
  	set_desc_next(chan, &tail->hw, desc->async_tx.phys);
  
  	/*
  	 * Add the software descriptor and all children to the list
  	 * of pending transactions
  	 */
  out_splice:
  	list_splice_tail_init(&desc->tx_list, &chan->ld_pending);
  }

  static dma_cookie_t fsl_dma_tx_submit(struct dma_async_tx_descriptor *tx)
  {

  	struct fsldma_chan *chan = to_fsl_chan(tx->chan);

  	struct fsl_desc_sw *desc = tx_to_fsl_desc(tx);
  	struct fsl_desc_sw *child;

  	dma_cookie_t cookie = -EINVAL;

  	spin_lock_bh(&chan->desc_lock);

  #ifdef CONFIG_PM
  	if (unlikely(chan->pm_state != RUNNING)) {
  		chan_dbg(chan, "cannot submit due to suspend
  ");
  		spin_unlock_bh(&chan->desc_lock);
  		return -1;
  	}
  #endif

  	/*
  	 * assign cookies to all of the software descriptors
  	 * that make up this transaction
  	 */

  	list_for_each_entry(child, &desc->tx_list, node) {

  		cookie = dma_cookie_assign(&child->async_tx);

  	}

  	/* put this transaction onto the tail of the pending queue */

  	append_ld_queue(chan, desc);

  	spin_unlock_bh(&chan->desc_lock);

  
  	return cookie;
  }
  
  /**

   * fsl_dma_free_descriptor - Free descriptor from channel's DMA pool.
   * @chan : Freescale DMA channel
   * @desc: descriptor to be freed
   */
  static void fsl_dma_free_descriptor(struct fsldma_chan *chan,
  		struct fsl_desc_sw *desc)
  {
  	list_del(&desc->node);
  	chan_dbg(chan, "LD %p free
  ", desc);
  	dma_pool_free(chan->desc_pool, desc, desc->async_tx.phys);
  }
  
  /**

   * fsl_dma_alloc_descriptor - Allocate descriptor from channel's DMA pool.

   * @chan : Freescale DMA channel

   *
   * Return - The descriptor allocated. NULL for failed.
   */

  static struct fsl_desc_sw *fsl_dma_alloc_descriptor(struct fsldma_chan *chan)

  {

  	struct fsl_desc_sw *desc;

  	dma_addr_t pdesc;

  	desc = dma_pool_zalloc(chan->desc_pool, GFP_ATOMIC, &pdesc);

  	if (!desc) {

  		chan_dbg(chan, "out of memory for link descriptor
  ");

  		return NULL;

  	}

  	INIT_LIST_HEAD(&desc->tx_list);
  	dma_async_tx_descriptor_init(&desc->async_tx, &chan->common);
  	desc->async_tx.tx_submit = fsl_dma_tx_submit;
  	desc->async_tx.phys = pdesc;

  	chan_dbg(chan, "LD %p allocated
  ", desc);

  	return desc;

  }

  /**

   * fsldma_clean_completed_descriptor - free all descriptors which
   * has been completed and acked
   * @chan: Freescale DMA channel
   *
   * This function is used on all completed and acked descriptors.
   * All descriptors should only be freed in this function.
   */
  static void fsldma_clean_completed_descriptor(struct fsldma_chan *chan)
  {
  	struct fsl_desc_sw *desc, *_desc;
  
  	/* Run the callback for each descriptor, in order */
  	list_for_each_entry_safe(desc, _desc, &chan->ld_completed, node)
  		if (async_tx_test_ack(&desc->async_tx))
  			fsl_dma_free_descriptor(chan, desc);
  }
  
  /**
   * fsldma_run_tx_complete_actions - cleanup a single link descriptor
   * @chan: Freescale DMA channel
   * @desc: descriptor to cleanup and free
   * @cookie: Freescale DMA transaction identifier
   *
   * This function is used on a descriptor which has been executed by the DMA
   * controller. It will run any callbacks, submit any dependencies.
   */
  static dma_cookie_t fsldma_run_tx_complete_actions(struct fsldma_chan *chan,
  		struct fsl_desc_sw *desc, dma_cookie_t cookie)
  {
  	struct dma_async_tx_descriptor *txd = &desc->async_tx;
  	dma_cookie_t ret = cookie;
  
  	BUG_ON(txd->cookie < 0);
  
  	if (txd->cookie > 0) {
  		ret = txd->cookie;

  		dma_descriptor_unmap(txd);

  		/* Run the link descriptor callback function */

  		dmaengine_desc_get_callback_invoke(txd, NULL);

  	}
  
  	/* Run any dependencies */
  	dma_run_dependencies(txd);
  
  	return ret;
  }
  
  /**
   * fsldma_clean_running_descriptor - move the completed descriptor from
   * ld_running to ld_completed
   * @chan: Freescale DMA channel
   * @desc: the descriptor which is completed
   *
   * Free the descriptor directly if acked by async_tx api, or move it to
   * queue ld_completed.
   */
  static void fsldma_clean_running_descriptor(struct fsldma_chan *chan,
  		struct fsl_desc_sw *desc)
  {
  	/* Remove from the list of transactions */
  	list_del(&desc->node);
  
  	/*
  	 * the client is allowed to attach dependent operations
  	 * until 'ack' is set
  	 */
  	if (!async_tx_test_ack(&desc->async_tx)) {
  		/*
  		 * Move this descriptor to the list of descriptors which is
  		 * completed, but still awaiting the 'ack' bit to be set.
  		 */
  		list_add_tail(&desc->node, &chan->ld_completed);
  		return;
  	}
  
  	dma_pool_free(chan->desc_pool, desc, desc->async_tx.phys);
  }
  
  /**

   * fsl_chan_xfer_ld_queue - transfer any pending transactions
   * @chan : Freescale DMA channel
   *
   * HARDWARE STATE: idle
   * LOCKING: must hold chan->desc_lock
   */
  static void fsl_chan_xfer_ld_queue(struct fsldma_chan *chan)
  {
  	struct fsl_desc_sw *desc;
  
  	/*
  	 * If the list of pending descriptors is empty, then we
  	 * don't need to do any work at all
  	 */
  	if (list_empty(&chan->ld_pending)) {
  		chan_dbg(chan, "no pending LDs
  ");
  		return;
  	}
  
  	/*
  	 * The DMA controller is not idle, which means that the interrupt
  	 * handler will start any queued transactions when it runs after
  	 * this transaction finishes
  	 */
  	if (!chan->idle) {
  		chan_dbg(chan, "DMA controller still busy
  ");
  		return;
  	}
  
  	/*
  	 * If there are some link descriptors which have not been
  	 * transferred, we need to start the controller
  	 */
  
  	/*
  	 * Move all elements from the queue of pending transactions
  	 * onto the list of running transactions
  	 */
  	chan_dbg(chan, "idle, starting controller
  ");
  	desc = list_first_entry(&chan->ld_pending, struct fsl_desc_sw, node);
  	list_splice_tail_init(&chan->ld_pending, &chan->ld_running);
  
  	/*
  	 * The 85xx DMA controller doesn't clear the channel start bit
  	 * automatically at the end of a transfer. Therefore we must clear
  	 * it in software before starting the transfer.
  	 */
  	if ((chan->feature & FSL_DMA_IP_MASK) == FSL_DMA_IP_85XX) {
  		u32 mode;
  
  		mode = get_mr(chan);
  		mode &= ~FSL_DMA_MR_CS;
  		set_mr(chan, mode);
  	}
  
  	/*
  	 * Program the descriptor's address into the DMA controller,
  	 * then start the DMA transaction
  	 */
  	set_cdar(chan, desc->async_tx.phys);
  	get_cdar(chan);
  
  	dma_start(chan);
  	chan->idle = false;
  }
  
  /**

   * fsldma_cleanup_descriptors - cleanup link descriptors which are completed
   * and move them to ld_completed to free until flag 'ack' is set

   * @chan: Freescale DMA channel

   *

   * This function is used on descriptors which have been executed by the DMA
   * controller. It will run any callbacks, submit any dependencies, then
   * free these descriptors if flag 'ack' is set.

   */

  static void fsldma_cleanup_descriptors(struct fsldma_chan *chan)

  {

  	struct fsl_desc_sw *desc, *_desc;
  	dma_cookie_t cookie = 0;
  	dma_addr_t curr_phys = get_cdar(chan);
  	int seen_current = 0;

  	fsldma_clean_completed_descriptor(chan);
  
  	/* Run the callback for each descriptor, in order */
  	list_for_each_entry_safe(desc, _desc, &chan->ld_running, node) {
  		/*
  		 * 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
  		 */
  		if (desc->async_tx.phys == curr_phys) {
  			seen_current = 1;
  			if (!dma_is_idle(chan))
  				break;
  		}
  
  		cookie = fsldma_run_tx_complete_actions(chan, desc, cookie);
  
  		fsldma_clean_running_descriptor(chan, desc);

  	}

  	/*
  	 * Start any pending transactions automatically
  	 *
  	 * In the ideal case, we keep the DMA controller busy while we go
  	 * ahead and free the descriptors below.
  	 */
  	fsl_chan_xfer_ld_queue(chan);

  	if (cookie > 0)
  		chan->common.completed_cookie = cookie;

  }
  
  /**

   * fsl_dma_alloc_chan_resources - Allocate resources for DMA channel.

   * @chan : Freescale DMA channel

   *
   * This function will create a dma pool for descriptor allocation.
   *
   * Return - The number of descriptors allocated.
   */

  static int fsl_dma_alloc_chan_resources(struct dma_chan *dchan)

  {

  	struct fsldma_chan *chan = to_fsl_chan(dchan);

  
  	/* Has this channel already been allocated? */

  	if (chan->desc_pool)

  		return 1;

  	/*
  	 * We need the descriptor to be aligned to 32bytes

  	 * for meeting FSL DMA specification requirement.
  	 */

  	chan->desc_pool = dma_pool_create(chan->name, chan->dev,

  					  sizeof(struct fsl_desc_sw),
  					  __alignof__(struct fsl_desc_sw), 0);

  	if (!chan->desc_pool) {

  		chan_err(chan, "unable to allocate descriptor pool
  ");

  		return -ENOMEM;

  	}

  	/* there is at least one descriptor free to be allocated */

  	return 1;
  }
  
  /**

   * fsldma_free_desc_list - Free all descriptors in a queue
   * @chan: Freescae DMA channel
   * @list: the list to free
   *
   * LOCKING: must hold chan->desc_lock
   */
  static void fsldma_free_desc_list(struct fsldma_chan *chan,
  				  struct list_head *list)
  {
  	struct fsl_desc_sw *desc, *_desc;

  	list_for_each_entry_safe(desc, _desc, list, node)
  		fsl_dma_free_descriptor(chan, desc);

  }
  
  static void fsldma_free_desc_list_reverse(struct fsldma_chan *chan,
  					  struct list_head *list)
  {
  	struct fsl_desc_sw *desc, *_desc;

  	list_for_each_entry_safe_reverse(desc, _desc, list, node)
  		fsl_dma_free_descriptor(chan, desc);

  }
  
  /**

   * fsl_dma_free_chan_resources - Free all resources of the channel.

   * @chan : Freescale DMA channel

   */

  static void fsl_dma_free_chan_resources(struct dma_chan *dchan)

  {

  	struct fsldma_chan *chan = to_fsl_chan(dchan);

  	chan_dbg(chan, "free all channel resources
  ");

  	spin_lock_bh(&chan->desc_lock);

  	fsldma_cleanup_descriptors(chan);

  	fsldma_free_desc_list(chan, &chan->ld_pending);
  	fsldma_free_desc_list(chan, &chan->ld_running);

  	fsldma_free_desc_list(chan, &chan->ld_completed);

  	spin_unlock_bh(&chan->desc_lock);

  	dma_pool_destroy(chan->desc_pool);

  	chan->desc_pool = NULL;

  }

  static struct dma_async_tx_descriptor *

  fsl_dma_prep_memcpy(struct dma_chan *dchan,
  	dma_addr_t dma_dst, dma_addr_t dma_src,

  	size_t len, unsigned long flags)
  {

  	struct fsldma_chan *chan;

  	struct fsl_desc_sw *first = NULL, *prev = NULL, *new;
  	size_t copy;

  	if (!dchan)

  		return NULL;
  
  	if (!len)
  		return NULL;

  	chan = to_fsl_chan(dchan);

  
  	do {
  
  		/* Allocate the link descriptor from DMA pool */

  		new = fsl_dma_alloc_descriptor(chan);

  		if (!new) {

  			chan_err(chan, "%s
  ", msg_ld_oom);

  			goto fail;

  		}

  		copy = min(len, (size_t)FSL_DMA_BCR_MAX_CNT);

  		set_desc_cnt(chan, &new->hw, copy);
  		set_desc_src(chan, &new->hw, dma_src);
  		set_desc_dst(chan, &new->hw, dma_dst);

  
  		if (!first)
  			first = new;
  		else

  			set_desc_next(chan, &prev->hw, new->async_tx.phys);

  
  		new->async_tx.cookie = 0;

  		async_tx_ack(&new->async_tx);

  
  		prev = new;
  		len -= copy;
  		dma_src += copy;

  		dma_dst += copy;

  
  		/* Insert the link descriptor to the LD ring */

  		list_add_tail(&new->node, &first->tx_list);

  	} while (len);

  	new->async_tx.flags = flags; /* client is in control of this ack */

  	new->async_tx.cookie = -EBUSY;

  	/* Set End-of-link to the last link descriptor of new list */

  	set_ld_eol(chan, new);

  	return &first->async_tx;
  
  fail:
  	if (!first)
  		return NULL;

  	fsldma_free_desc_list_reverse(chan, &first->tx_list);

  	return NULL;

  }

  static int fsl_dma_device_terminate_all(struct dma_chan *dchan)

  {

  	struct fsldma_chan *chan;

  	if (!dchan)

  		return -EINVAL;

  	chan = to_fsl_chan(dchan);

  	spin_lock_bh(&chan->desc_lock);

  	/* Halt the DMA engine */
  	dma_halt(chan);

  	/* Remove and free all of the descriptors in the LD queue */
  	fsldma_free_desc_list(chan, &chan->ld_pending);
  	fsldma_free_desc_list(chan, &chan->ld_running);
  	fsldma_free_desc_list(chan, &chan->ld_completed);
  	chan->idle = true;

  	spin_unlock_bh(&chan->desc_lock);
  	return 0;
  }

  static int fsl_dma_device_config(struct dma_chan *dchan,
  				 struct dma_slave_config *config)
  {
  	struct fsldma_chan *chan;
  	int size;

  	if (!dchan)
  		return -EINVAL;

  	chan = to_fsl_chan(dchan);

  	/* make sure the channel supports setting burst size */
  	if (!chan->set_request_count)

  		return -ENXIO;

  	/* we set the controller burst size depending on direction */
  	if (config->direction == DMA_MEM_TO_DEV)
  		size = config->dst_addr_width * config->dst_maxburst;
  	else
  		size = config->src_addr_width * config->src_maxburst;
  
  	chan->set_request_count(chan, size);

  	return 0;

  }

  /**

   * fsl_dma_memcpy_issue_pending - Issue the DMA start command

   * @chan : Freescale DMA channel

   */

  static void fsl_dma_memcpy_issue_pending(struct dma_chan *dchan)

  {

  	struct fsldma_chan *chan = to_fsl_chan(dchan);

  	spin_lock_bh(&chan->desc_lock);

  	fsl_chan_xfer_ld_queue(chan);

  	spin_unlock_bh(&chan->desc_lock);

  }

  /**

   * fsl_tx_status - Determine the DMA status

   * @chan : Freescale DMA channel

   */

  static enum dma_status fsl_tx_status(struct dma_chan *dchan,

  					dma_cookie_t cookie,

  					struct dma_tx_state *txstate)

  {

  	struct fsldma_chan *chan = to_fsl_chan(dchan);
  	enum dma_status ret;
  
  	ret = dma_cookie_status(dchan, cookie, txstate);
  	if (ret == DMA_COMPLETE)
  		return ret;
  
  	spin_lock_bh(&chan->desc_lock);
  	fsldma_cleanup_descriptors(chan);
  	spin_unlock_bh(&chan->desc_lock);

  	return dma_cookie_status(dchan, cookie, txstate);

  }

  /*----------------------------------------------------------------------------*/
  /* Interrupt Handling                                                         */
  /*----------------------------------------------------------------------------*/

  static irqreturn_t fsldma_chan_irq(int irq, void *data)

  {

  	struct fsldma_chan *chan = data;

  	u32 stat;

  	/* save and clear the status register */

  	stat = get_sr(chan);

  	set_sr(chan, stat);

  	chan_dbg(chan, "irq: stat = 0x%x
  ", stat);

  	/* check that this was really our device */

  	stat &= ~(FSL_DMA_SR_CB | FSL_DMA_SR_CH);
  	if (!stat)
  		return IRQ_NONE;
  
  	if (stat & FSL_DMA_SR_TE)

  		chan_err(chan, "Transfer Error!
  ");

  	/*
  	 * Programming Error

  	 * The DMA_INTERRUPT async_tx is a NULL transfer, which will

  	 * trigger a PE interrupt.

  	 */
  	if (stat & FSL_DMA_SR_PE) {

  		chan_dbg(chan, "irq: Programming Error INT
  ");

  		stat &= ~FSL_DMA_SR_PE;

  		if (get_bcr(chan) != 0)
  			chan_err(chan, "Programming Error!
  ");

  	}

  	/*
  	 * For MPC8349, EOCDI event need to update cookie

  	 * and start the next transfer if it exist.
  	 */
  	if (stat & FSL_DMA_SR_EOCDI) {

  		chan_dbg(chan, "irq: End-of-Chain link INT
  ");

  		stat &= ~FSL_DMA_SR_EOCDI;

  	}

  	/*
  	 * If it current transfer is the end-of-transfer,

  	 * we should clear the Channel Start bit for
  	 * prepare next transfer.
  	 */

  	if (stat & FSL_DMA_SR_EOLNI) {

  		chan_dbg(chan, "irq: End-of-link INT
  ");

  		stat &= ~FSL_DMA_SR_EOLNI;

  	}

  	/* check that the DMA controller is really idle */
  	if (!dma_is_idle(chan))
  		chan_err(chan, "irq: controller not idle!
  ");
  
  	/* check that we handled all of the bits */

  	if (stat)

  		chan_err(chan, "irq: unhandled sr 0x%08x
  ", stat);

  	/*
  	 * Schedule the tasklet to handle all cleanup of the current
  	 * transaction. It will start a new transaction if there is
  	 * one pending.
  	 */

  	tasklet_schedule(&chan->tasklet);

  	chan_dbg(chan, "irq: Exit
  ");

  	return IRQ_HANDLED;
  }

  static void dma_do_tasklet(struct tasklet_struct *t)

  {

  	struct fsldma_chan *chan = from_tasklet(chan, t, tasklet);

  
  	chan_dbg(chan, "tasklet entry
  ");

  	spin_lock(&chan->desc_lock);

  	/* the hardware is now idle and ready for more */

  	chan->idle = true;

  	/* Run all cleanup for descriptors which have been completed */
  	fsldma_cleanup_descriptors(chan);

  	spin_unlock(&chan->desc_lock);

  	chan_dbg(chan, "tasklet exit
  ");

  }
  
  static irqreturn_t fsldma_ctrl_irq(int irq, void *data)

  {

  	struct fsldma_device *fdev = data;

  	struct fsldma_chan *chan;
  	unsigned int handled = 0;
  	u32 gsr, mask;
  	int i;

  	gsr = (fdev->feature & FSL_DMA_BIG_ENDIAN) ? in_be32(fdev->regs)

  						   : in_le32(fdev->regs);
  	mask = 0xff000000;
  	dev_dbg(fdev->dev, "IRQ: gsr 0x%.8x
  ", gsr);

  	for (i = 0; i < FSL_DMA_MAX_CHANS_PER_DEVICE; i++) {
  		chan = fdev->chan[i];
  		if (!chan)
  			continue;
  
  		if (gsr & mask) {
  			dev_dbg(fdev->dev, "IRQ: chan %d
  ", chan->id);
  			fsldma_chan_irq(irq, chan);
  			handled++;
  		}
  
  		gsr &= ~mask;
  		mask >>= 8;
  	}
  
  	return IRQ_RETVAL(handled);

  }

  static void fsldma_free_irqs(struct fsldma_device *fdev)

  {

  	struct fsldma_chan *chan;
  	int i;

  	if (fdev->irq) {

  		dev_dbg(fdev->dev, "free per-controller IRQ
  ");
  		free_irq(fdev->irq, fdev);
  		return;
  	}
  
  	for (i = 0; i < FSL_DMA_MAX_CHANS_PER_DEVICE; i++) {
  		chan = fdev->chan[i];

  		if (chan && chan->irq) {

  			chan_dbg(chan, "free per-channel IRQ
  ");

  			free_irq(chan->irq, chan);
  		}
  	}
  }
  
  static int fsldma_request_irqs(struct fsldma_device *fdev)
  {
  	struct fsldma_chan *chan;
  	int ret;
  	int i;
  
  	/* if we have a per-controller IRQ, use that */

  	if (fdev->irq) {

  		dev_dbg(fdev->dev, "request per-controller IRQ
  ");
  		ret = request_irq(fdev->irq, fsldma_ctrl_irq, IRQF_SHARED,
  				  "fsldma-controller", fdev);
  		return ret;
  	}
  
  	/* no per-controller IRQ, use the per-channel IRQs */
  	for (i = 0; i < FSL_DMA_MAX_CHANS_PER_DEVICE; i++) {
  		chan = fdev->chan[i];
  		if (!chan)
  			continue;

  		if (!chan->irq) {

  			chan_err(chan, "interrupts property missing in device tree
  ");

  			ret = -ENODEV;
  			goto out_unwind;
  		}

  		chan_dbg(chan, "request per-channel IRQ
  ");

  		ret = request_irq(chan->irq, fsldma_chan_irq, IRQF_SHARED,
  				  "fsldma-chan", chan);
  		if (ret) {

  			chan_err(chan, "unable to request per-channel IRQ
  ");

  			goto out_unwind;
  		}
  	}
  
  	return 0;
  
  out_unwind:
  	for (/* none */; i >= 0; i--) {
  		chan = fdev->chan[i];
  		if (!chan)
  			continue;

  		if (!chan->irq)

  			continue;
  
  		free_irq(chan->irq, chan);
  	}
  
  	return ret;

  }

  /*----------------------------------------------------------------------------*/
  /* OpenFirmware Subsystem                                                     */
  /*----------------------------------------------------------------------------*/

  static int fsl_dma_chan_probe(struct fsldma_device *fdev,

  	struct device_node *node, u32 feature, const char *compatible)

  {

  	struct fsldma_chan *chan;

  	struct resource res;

  	int err;

  	/* alloc channel */

  	chan = kzalloc(sizeof(*chan), GFP_KERNEL);
  	if (!chan) {

  		err = -ENOMEM;
  		goto out_return;
  	}
  
  	/* ioremap registers for use */

  	chan->regs = of_iomap(node, 0);
  	if (!chan->regs) {

  		dev_err(fdev->dev, "unable to ioremap registers
  ");
  		err = -ENOMEM;

  		goto out_free_chan;

  	}

  	err = of_address_to_resource(node, 0, &res);

  	if (err) {

  		dev_err(fdev->dev, "unable to find 'reg' property
  ");
  		goto out_iounmap_regs;

  	}

  	chan->feature = feature;

  	if (!fdev->feature)

  		fdev->feature = chan->feature;

  	/*
  	 * If the DMA device's feature is different than the feature
  	 * of its channels, report the bug

  	 */

  	WARN_ON(fdev->feature != chan->feature);

  	chan->dev = fdev->dev;

  	chan->id = (res.start & 0xfff) < 0x300 ?
  		   ((res.start - 0x100) & 0xfff) >> 7 :
  		   ((res.start - 0x200) & 0xfff) >> 7;

  	if (chan->id >= FSL_DMA_MAX_CHANS_PER_DEVICE) {

  		dev_err(fdev->dev, "too many channels for device
  ");

  		err = -EINVAL;

  		goto out_iounmap_regs;

  	}

  	fdev->chan[chan->id] = chan;

  	tasklet_setup(&chan->tasklet, dma_do_tasklet);

  	snprintf(chan->name, sizeof(chan->name), "chan%d", chan->id);

  
  	/* Initialize the channel */

  	dma_init(chan);

  
  	/* Clear cdar registers */

  	set_cdar(chan, 0);

  	switch (chan->feature & FSL_DMA_IP_MASK) {

  	case FSL_DMA_IP_85XX:

  		chan->toggle_ext_pause = fsl_chan_toggle_ext_pause;

  		fallthrough;

  	case FSL_DMA_IP_83XX:

  		chan->toggle_ext_start = fsl_chan_toggle_ext_start;
  		chan->set_src_loop_size = fsl_chan_set_src_loop_size;
  		chan->set_dst_loop_size = fsl_chan_set_dst_loop_size;
  		chan->set_request_count = fsl_chan_set_request_count;

  	}

  	spin_lock_init(&chan->desc_lock);

  	INIT_LIST_HEAD(&chan->ld_pending);
  	INIT_LIST_HEAD(&chan->ld_running);

  	INIT_LIST_HEAD(&chan->ld_completed);

  	chan->idle = true;

  #ifdef CONFIG_PM
  	chan->pm_state = RUNNING;
  #endif

  	chan->common.device = &fdev->common;

  	dma_cookie_init(&chan->common);

  	/* find the IRQ line, if it exists in the device tree */

  	chan->irq = irq_of_parse_and_map(node, 0);

  	/* Add the channel to DMA device channel list */

  	list_add_tail(&chan->common.device_node, &fdev->common.channels);

  	dev_info(fdev->dev, "#%d (%s), irq %d
  ", chan->id, compatible,

  		 chan->irq ? chan->irq : fdev->irq);

  
  	return 0;

  out_iounmap_regs:

  	iounmap(chan->regs);
  out_free_chan:
  	kfree(chan);

  out_return:

  	return err;
  }

  static void fsl_dma_chan_remove(struct fsldma_chan *chan)

  {

  	irq_dispose_mapping(chan->irq);
  	list_del(&chan->common.device_node);
  	iounmap(chan->regs);
  	kfree(chan);

  }

  static int fsldma_of_probe(struct platform_device *op)

  {

  	struct fsldma_device *fdev;

  	struct device_node *child;

  	int err;

  	fdev = kzalloc(sizeof(*fdev), GFP_KERNEL);

  	if (!fdev) {

  		err = -ENOMEM;
  		goto out_return;

  	}

  
  	fdev->dev = &op->dev;

  	INIT_LIST_HEAD(&fdev->common.channels);

  	/* ioremap the registers for use */

  	fdev->regs = of_iomap(op->dev.of_node, 0);

  	if (!fdev->regs) {
  		dev_err(&op->dev, "unable to ioremap registers
  ");
  		err = -ENOMEM;

  		goto out_free;

  	}

  	/* map the channel IRQ if it exists, but don't hookup the handler yet */

  	fdev->irq = irq_of_parse_and_map(op->dev.of_node, 0);

  	dma_cap_set(DMA_MEMCPY, fdev->common.cap_mask);

  	dma_cap_set(DMA_SLAVE, fdev->common.cap_mask);

  	fdev->common.device_alloc_chan_resources = fsl_dma_alloc_chan_resources;
  	fdev->common.device_free_chan_resources = fsl_dma_free_chan_resources;
  	fdev->common.device_prep_dma_memcpy = fsl_dma_prep_memcpy;

  	fdev->common.device_tx_status = fsl_tx_status;

  	fdev->common.device_issue_pending = fsl_dma_memcpy_issue_pending;

  	fdev->common.device_config = fsl_dma_device_config;
  	fdev->common.device_terminate_all = fsl_dma_device_terminate_all;

  	fdev->common.dev = &op->dev;

  	fdev->common.src_addr_widths = FSL_DMA_BUSWIDTHS;
  	fdev->common.dst_addr_widths = FSL_DMA_BUSWIDTHS;
  	fdev->common.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
  	fdev->common.residue_granularity = DMA_RESIDUE_GRANULARITY_DESCRIPTOR;

  	dma_set_mask(&(op->dev), DMA_BIT_MASK(36));

  	platform_set_drvdata(op, fdev);

  	/*
  	 * We cannot use of_platform_bus_probe() because there is no
  	 * of_platform_bus_remove(). Instead, we manually instantiate every DMA

  	 * channel object.
  	 */

  	for_each_child_of_node(op->dev.of_node, child) {

  		if (of_device_is_compatible(child, "fsl,eloplus-dma-channel")) {

  			fsl_dma_chan_probe(fdev, child,
  				FSL_DMA_IP_85XX | FSL_DMA_BIG_ENDIAN,
  				"fsl,eloplus-dma-channel");

  		}
  
  		if (of_device_is_compatible(child, "fsl,elo-dma-channel")) {

  			fsl_dma_chan_probe(fdev, child,
  				FSL_DMA_IP_83XX | FSL_DMA_LITTLE_ENDIAN,
  				"fsl,elo-dma-channel");

  		}

  	}

  	/*
  	 * Hookup the IRQ handler(s)
  	 *
  	 * If we have a per-controller interrupt, we prefer that to the
  	 * per-channel interrupts to reduce the number of shared interrupt
  	 * handlers on the same IRQ line
  	 */
  	err = fsldma_request_irqs(fdev);
  	if (err) {
  		dev_err(fdev->dev, "unable to request IRQs
  ");
  		goto out_free_fdev;
  	}

  	dma_async_device_register(&fdev->common);
  	return 0;

  out_free_fdev:

  	irq_dispose_mapping(fdev->irq);

  	iounmap(fdev->regs);
  out_free:

  	kfree(fdev);

  out_return:

  	return err;
  }

  static int fsldma_of_remove(struct platform_device *op)

  {

  	struct fsldma_device *fdev;

  	unsigned int i;

  	fdev = platform_get_drvdata(op);

  	dma_async_device_unregister(&fdev->common);

  	fsldma_free_irqs(fdev);

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

  		if (fdev->chan[i])
  			fsl_dma_chan_remove(fdev->chan[i]);

  	}

  	iounmap(fdev->regs);

  	kfree(fdev);

  
  	return 0;
  }

  #ifdef CONFIG_PM
  static int fsldma_suspend_late(struct device *dev)
  {

  	struct fsldma_device *fdev = dev_get_drvdata(dev);

  	struct fsldma_chan *chan;
  	int i;
  
  	for (i = 0; i < FSL_DMA_MAX_CHANS_PER_DEVICE; i++) {
  		chan = fdev->chan[i];
  		if (!chan)
  			continue;
  
  		spin_lock_bh(&chan->desc_lock);
  		if (unlikely(!chan->idle))
  			goto out;
  		chan->regs_save.mr = get_mr(chan);
  		chan->pm_state = SUSPENDED;
  		spin_unlock_bh(&chan->desc_lock);
  	}
  	return 0;
  
  out:
  	for (; i >= 0; i--) {
  		chan = fdev->chan[i];
  		if (!chan)
  			continue;
  		chan->pm_state = RUNNING;
  		spin_unlock_bh(&chan->desc_lock);
  	}
  	return -EBUSY;
  }
  
  static int fsldma_resume_early(struct device *dev)
  {

  	struct fsldma_device *fdev = dev_get_drvdata(dev);

  	struct fsldma_chan *chan;
  	u32 mode;
  	int i;
  
  	for (i = 0; i < FSL_DMA_MAX_CHANS_PER_DEVICE; i++) {
  		chan = fdev->chan[i];
  		if (!chan)
  			continue;
  
  		spin_lock_bh(&chan->desc_lock);
  		mode = chan->regs_save.mr
  			& ~FSL_DMA_MR_CS & ~FSL_DMA_MR_CC & ~FSL_DMA_MR_CA;
  		set_mr(chan, mode);
  		chan->pm_state = RUNNING;
  		spin_unlock_bh(&chan->desc_lock);
  	}
  
  	return 0;
  }
  
  static const struct dev_pm_ops fsldma_pm_ops = {
  	.suspend_late	= fsldma_suspend_late,
  	.resume_early	= fsldma_resume_early,
  };
  #endif

  static const struct of_device_id fsldma_of_ids[] = {

  	{ .compatible = "fsl,elo3-dma", },

  	{ .compatible = "fsl,eloplus-dma", },
  	{ .compatible = "fsl,elo-dma", },

  	{}
  };

  MODULE_DEVICE_TABLE(of, fsldma_of_ids);

  static struct platform_driver fsldma_of_driver = {

  	.driver = {
  		.name = "fsl-elo-dma",

  		.of_match_table = fsldma_of_ids,

  #ifdef CONFIG_PM
  		.pm = &fsldma_pm_ops,
  #endif

  	},
  	.probe = fsldma_of_probe,
  	.remove = fsldma_of_remove,

  };

  /*----------------------------------------------------------------------------*/
  /* Module Init / Exit                                                         */
  /*----------------------------------------------------------------------------*/
  
  static __init int fsldma_init(void)

  {

  	pr_info("Freescale Elo series DMA driver
  ");

  	return platform_driver_register(&fsldma_of_driver);

  }

  static void __exit fsldma_exit(void)

  {

  	platform_driver_unregister(&fsldma_of_driver);

  }

  subsys_initcall(fsldma_init);
  module_exit(fsldma_exit);

  MODULE_DESCRIPTION("Freescale Elo series DMA driver");

  MODULE_LICENSE("GPL");