/*
   * Copyright(c) 2004 - 2006 Intel Corporation. All rights reserved.
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License as published by the Free
   * Software Foundation; either version 2 of the License, or (at your option)
   * any later version.
   *
   * This program is distributed in the hope that 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., 59
   * Temple Place - Suite 330, Boston, MA  02111-1307, USA.
   *
   * The full GNU General Public License is included in this distribution in the
   * file called COPYING.
   */
  #ifndef DMAENGINE_H
  #define DMAENGINE_H

  #include <linux/device.h>
  #include <linux/uio.h>

  #include <linux/dma-direction.h>

  #include <linux/scatterlist.h>

  #include <linux/bitmap.h>
  #include <asm/page.h>

  /**

   * typedef dma_cookie_t - an opaque DMA cookie

   *
   * if dma_cookie_t is >0 it's a DMA request cookie, <0 it's an error code
   */
  typedef s32 dma_cookie_t;

  #define DMA_MIN_COOKIE	1
  #define DMA_MAX_COOKIE	INT_MAX

  
  #define dma_submit_error(cookie) ((cookie) < 0 ? 1 : 0)
  
  /**
   * enum dma_status - DMA transaction status
   * @DMA_SUCCESS: transaction completed successfully
   * @DMA_IN_PROGRESS: transaction not yet processed

   * @DMA_PAUSED: transaction is paused

   * @DMA_ERROR: transaction failed
   */
  enum dma_status {
  	DMA_SUCCESS,
  	DMA_IN_PROGRESS,

  	DMA_PAUSED,

  	DMA_ERROR,
  };
  
  /**

   * enum dma_transaction_type - DMA transaction types/indexes

   *
   * Note: The DMA_ASYNC_TX capability is not to be set by drivers.  It is
   * automatically set as dma devices are registered.

   */
  enum dma_transaction_type {
  	DMA_MEMCPY,
  	DMA_XOR,

  	DMA_PQ,

  	DMA_XOR_VAL,
  	DMA_PQ_VAL,

  	DMA_MEMSET,

  	DMA_INTERRUPT,

  	DMA_SG,

  	DMA_PRIVATE,

  	DMA_ASYNC_TX,

  	DMA_SLAVE,

  	DMA_CYCLIC,

  };
  
  /* last transaction type for creation of the capabilities mask */

  #define DMA_TX_TYPE_END (DMA_CYCLIC + 1)

  
  /**

   * enum dma_ctrl_flags - DMA flags to augment operation preparation,

   *  control completion, and communicate status.

   * @DMA_PREP_INTERRUPT - trigger an interrupt (callback) upon completion of

   *  this transaction

   * @DMA_CTRL_ACK - if clear, the descriptor cannot be reused until the client

   *  acknowledges receipt, i.e. has has a chance to establish any dependency
   *  chains

   * @DMA_COMPL_SKIP_SRC_UNMAP - set to disable dma-unmapping the source buffer(s)
   * @DMA_COMPL_SKIP_DEST_UNMAP - set to disable dma-unmapping the destination(s)

   * @DMA_COMPL_SRC_UNMAP_SINGLE - set to do the source dma-unmapping as single
   * 	(if not set, do the source dma-unmapping as page)
   * @DMA_COMPL_DEST_UNMAP_SINGLE - set to do the destination dma-unmapping as single
   * 	(if not set, do the destination dma-unmapping as page)

   * @DMA_PREP_PQ_DISABLE_P - prevent generation of P while generating Q
   * @DMA_PREP_PQ_DISABLE_Q - prevent generation of Q while generating P
   * @DMA_PREP_CONTINUE - indicate to a driver that it is reusing buffers as
   *  sources that were the result of a previous operation, in the case of a PQ
   *  operation it continues the calculation with new sources

   * @DMA_PREP_FENCE - tell the driver that subsequent operations depend
   *  on the result of this operation

   */

  enum dma_ctrl_flags {

  	DMA_PREP_INTERRUPT = (1 << 0),

  	DMA_CTRL_ACK = (1 << 1),

  	DMA_COMPL_SKIP_SRC_UNMAP = (1 << 2),
  	DMA_COMPL_SKIP_DEST_UNMAP = (1 << 3),

  	DMA_COMPL_SRC_UNMAP_SINGLE = (1 << 4),
  	DMA_COMPL_DEST_UNMAP_SINGLE = (1 << 5),

  	DMA_PREP_PQ_DISABLE_P = (1 << 6),
  	DMA_PREP_PQ_DISABLE_Q = (1 << 7),
  	DMA_PREP_CONTINUE = (1 << 8),

  	DMA_PREP_FENCE = (1 << 9),

  };
  
  /**

   * enum dma_ctrl_cmd - DMA operations that can optionally be exercised
   * on a running channel.
   * @DMA_TERMINATE_ALL: terminate all ongoing transfers
   * @DMA_PAUSE: pause ongoing transfers
   * @DMA_RESUME: resume paused transfer

   * @DMA_SLAVE_CONFIG: this command is only implemented by DMA controllers
   * that need to runtime reconfigure the slave channels (as opposed to passing
   * configuration data in statically from the platform). An additional
   * argument of struct dma_slave_config must be passed in with this
   * command.

   * @FSLDMA_EXTERNAL_START: this command will put the Freescale DMA controller
   * into external start mode.

   */
  enum dma_ctrl_cmd {
  	DMA_TERMINATE_ALL,
  	DMA_PAUSE,
  	DMA_RESUME,

  	DMA_SLAVE_CONFIG,

  	FSLDMA_EXTERNAL_START,

  };
  
  /**

   * enum sum_check_bits - bit position of pq_check_flags
   */
  enum sum_check_bits {
  	SUM_CHECK_P = 0,
  	SUM_CHECK_Q = 1,
  };
  
  /**
   * enum pq_check_flags - result of async_{xor,pq}_zero_sum operations
   * @SUM_CHECK_P_RESULT - 1 if xor zero sum error, 0 otherwise
   * @SUM_CHECK_Q_RESULT - 1 if reed-solomon zero sum error, 0 otherwise
   */
  enum sum_check_flags {
  	SUM_CHECK_P_RESULT = (1 << SUM_CHECK_P),
  	SUM_CHECK_Q_RESULT = (1 << SUM_CHECK_Q),
  };
  
  
  /**

   * dma_cap_mask_t - capabilities bitmap modeled after cpumask_t.
   * See linux/cpumask.h
   */
  typedef struct { DECLARE_BITMAP(bits, DMA_TX_TYPE_END); } dma_cap_mask_t;
  
  /**

   * struct dma_chan_percpu - the per-CPU part of struct dma_chan

   * @memcpy_count: transaction counter
   * @bytes_transferred: byte counter
   */
  
  struct dma_chan_percpu {

  	/* stats */
  	unsigned long memcpy_count;
  	unsigned long bytes_transferred;
  };
  
  /**
   * struct dma_chan - devices supply DMA channels, clients use them

   * @device: ptr to the dma device who supplies this channel, always !%NULL

   * @cookie: last cookie value returned to client

   * @chan_id: channel ID for sysfs

   * @dev: class device for sysfs

   * @device_node: used to add this to the device chan list
   * @local: per-cpu pointer to a struct dma_chan_percpu

   * @client-count: how many clients are using this channel

   * @table_count: number of appearances in the mem-to-mem allocation table

   * @private: private data for certain client-channel associations

   */
  struct dma_chan {

  	struct dma_device *device;
  	dma_cookie_t cookie;
  
  	/* sysfs */
  	int chan_id;

  	struct dma_chan_dev *dev;

  	struct list_head device_node;

  	struct dma_chan_percpu __percpu *local;

  	int client_count;

  	int table_count;

  	void *private;

  };

  /**
   * struct dma_chan_dev - relate sysfs device node to backing channel device
   * @chan - driver channel device
   * @device - sysfs device

   * @dev_id - parent dma_device dev_id
   * @idr_ref - reference count to gate release of dma_device dev_id

   */
  struct dma_chan_dev {
  	struct dma_chan *chan;
  	struct device device;

  	int dev_id;
  	atomic_t *idr_ref;

  };

  /**
   * enum dma_slave_buswidth - defines bus with of the DMA slave
   * device, source or target buses
   */
  enum dma_slave_buswidth {
  	DMA_SLAVE_BUSWIDTH_UNDEFINED = 0,
  	DMA_SLAVE_BUSWIDTH_1_BYTE = 1,
  	DMA_SLAVE_BUSWIDTH_2_BYTES = 2,
  	DMA_SLAVE_BUSWIDTH_4_BYTES = 4,
  	DMA_SLAVE_BUSWIDTH_8_BYTES = 8,
  };
  
  /**
   * struct dma_slave_config - dma slave channel runtime config
   * @direction: whether the data shall go in or out on this slave
   * channel, right now. DMA_TO_DEVICE and DMA_FROM_DEVICE are
   * legal values, DMA_BIDIRECTIONAL is not acceptable since we
   * need to differentiate source and target addresses.
   * @src_addr: this is the physical address where DMA slave data
   * should be read (RX), if the source is memory this argument is
   * ignored.
   * @dst_addr: this is the physical address where DMA slave data
   * should be written (TX), if the source is memory this argument
   * is ignored.
   * @src_addr_width: this is the width in bytes of the source (RX)
   * register where DMA data shall be read. If the source
   * is memory this may be ignored depending on architecture.
   * Legal values: 1, 2, 4, 8.
   * @dst_addr_width: same as src_addr_width but for destination
   * target (TX) mutatis mutandis.
   * @src_maxburst: the maximum number of words (note: words, as in
   * units of the src_addr_width member, not bytes) that can be sent
   * in one burst to the device. Typically something like half the
   * FIFO depth on I/O peripherals so you don't overflow it. This
   * may or may not be applicable on memory sources.
   * @dst_maxburst: same as src_maxburst but for destination target
   * mutatis mutandis.
   *
   * This struct is passed in as configuration data to a DMA engine
   * in order to set up a certain channel for DMA transport at runtime.
   * The DMA device/engine has to provide support for an additional
   * command in the channel config interface, DMA_SLAVE_CONFIG
   * and this struct will then be passed in as an argument to the
   * DMA engine device_control() function.
   *
   * The rationale for adding configuration information to this struct
   * is as follows: if it is likely that most DMA slave controllers in
   * the world will support the configuration option, then make it
   * generic. If not: if it is fixed so that it be sent in static from
   * the platform data, then prefer to do that. Else, if it is neither
   * fixed at runtime, nor generic enough (such as bus mastership on
   * some CPU family and whatnot) then create a custom slave config
   * struct and pass that, then make this config a member of that
   * struct, if applicable.
   */
  struct dma_slave_config {
  	enum dma_data_direction direction;
  	dma_addr_t src_addr;
  	dma_addr_t dst_addr;
  	enum dma_slave_buswidth src_addr_width;
  	enum dma_slave_buswidth dst_addr_width;
  	u32 src_maxburst;
  	u32 dst_maxburst;
  };

  static inline const char *dma_chan_name(struct dma_chan *chan)
  {
  	return dev_name(&chan->dev->device);
  }

  void dma_chan_cleanup(struct kref *kref);

  /**

   * typedef dma_filter_fn - callback filter for dma_request_channel
   * @chan: channel to be reviewed
   * @filter_param: opaque parameter passed through dma_request_channel
   *
   * When this optional parameter is specified in a call to dma_request_channel a
   * suitable channel is passed to this routine for further dispositioning before
   * being returned.  Where 'suitable' indicates a non-busy channel that

   * satisfies the given capability mask.  It returns 'true' to indicate that the
   * channel is suitable.

   */

  typedef bool (*dma_filter_fn)(struct dma_chan *chan, void *filter_param);

  typedef void (*dma_async_tx_callback)(void *dma_async_param);
  /**
   * struct dma_async_tx_descriptor - async transaction descriptor
   * ---dma generic offload fields---
   * @cookie: tracking cookie for this transaction, set to -EBUSY if
   *	this tx is sitting on a dependency list

   * @flags: flags to augment operation preparation, control completion, and
   * 	communicate status

   * @phys: physical address of the descriptor

   * @chan: target channel for this operation
   * @tx_submit: set the prepared descriptor(s) to be executed by the engine

   * @callback: routine to call after this operation is complete
   * @callback_param: general parameter to pass to the callback routine
   * ---async_tx api specific fields---

   * @next: at completion submit this descriptor

   * @parent: pointer to the next level up in the dependency chain

   * @lock: protect the parent and next pointers

   */
  struct dma_async_tx_descriptor {
  	dma_cookie_t cookie;

  	enum dma_ctrl_flags flags; /* not a 'long' to pack with cookie */

  	dma_addr_t phys;

  	struct dma_chan *chan;
  	dma_cookie_t (*tx_submit)(struct dma_async_tx_descriptor *tx);

  	dma_async_tx_callback callback;
  	void *callback_param;

  #ifdef CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH

  	struct dma_async_tx_descriptor *next;

  	struct dma_async_tx_descriptor *parent;
  	spinlock_t lock;

  #endif

  };

  #ifndef CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH

  static inline void txd_lock(struct dma_async_tx_descriptor *txd)
  {
  }
  static inline void txd_unlock(struct dma_async_tx_descriptor *txd)
  {
  }
  static inline void txd_chain(struct dma_async_tx_descriptor *txd, struct dma_async_tx_descriptor *next)
  {
  	BUG();
  }
  static inline void txd_clear_parent(struct dma_async_tx_descriptor *txd)
  {
  }
  static inline void txd_clear_next(struct dma_async_tx_descriptor *txd)
  {
  }
  static inline struct dma_async_tx_descriptor *txd_next(struct dma_async_tx_descriptor *txd)
  {
  	return NULL;
  }
  static inline struct dma_async_tx_descriptor *txd_parent(struct dma_async_tx_descriptor *txd)
  {
  	return NULL;
  }
  
  #else
  static inline void txd_lock(struct dma_async_tx_descriptor *txd)
  {
  	spin_lock_bh(&txd->lock);
  }
  static inline void txd_unlock(struct dma_async_tx_descriptor *txd)
  {
  	spin_unlock_bh(&txd->lock);
  }
  static inline void txd_chain(struct dma_async_tx_descriptor *txd, struct dma_async_tx_descriptor *next)
  {
  	txd->next = next;
  	next->parent = txd;
  }
  static inline void txd_clear_parent(struct dma_async_tx_descriptor *txd)
  {
  	txd->parent = NULL;
  }
  static inline void txd_clear_next(struct dma_async_tx_descriptor *txd)
  {
  	txd->next = NULL;
  }
  static inline struct dma_async_tx_descriptor *txd_parent(struct dma_async_tx_descriptor *txd)
  {
  	return txd->parent;
  }
  static inline struct dma_async_tx_descriptor *txd_next(struct dma_async_tx_descriptor *txd)
  {
  	return txd->next;
  }
  #endif

  /**

   * struct dma_tx_state - filled in to report the status of
   * a transfer.
   * @last: last completed DMA cookie
   * @used: last issued DMA cookie (i.e. the one in progress)
   * @residue: the remaining number of bytes left to transmit
   *	on the selected transfer for states DMA_IN_PROGRESS and
   *	DMA_PAUSED if this is implemented in the driver, else 0
   */
  struct dma_tx_state {
  	dma_cookie_t last;
  	dma_cookie_t used;
  	u32 residue;
  };
  
  /**

   * struct dma_device - info on the entity supplying DMA services
   * @chancnt: how many DMA channels are supported

   * @privatecnt: how many DMA channels are requested by dma_request_channel

   * @channels: the list of struct dma_chan
   * @global_node: list_head for global dma_device_list

   * @cap_mask: one or more dma_capability flags
   * @max_xor: maximum number of xor sources, 0 if no capability

   * @max_pq: maximum number of PQ sources and PQ-continue capability

   * @copy_align: alignment shift for memcpy operations
   * @xor_align: alignment shift for xor operations
   * @pq_align: alignment shift for pq operations
   * @fill_align: alignment shift for memset operations

   * @dev_id: unique device ID

   * @dev: struct device reference for dma mapping api

   * @device_alloc_chan_resources: allocate resources and return the
   *	number of allocated descriptors
   * @device_free_chan_resources: release DMA channel's resources

   * @device_prep_dma_memcpy: prepares a memcpy operation
   * @device_prep_dma_xor: prepares a xor operation

   * @device_prep_dma_xor_val: prepares a xor validation operation

   * @device_prep_dma_pq: prepares a pq operation
   * @device_prep_dma_pq_val: prepares a pqzero_sum operation

   * @device_prep_dma_memset: prepares a memset operation
   * @device_prep_dma_interrupt: prepares an end of chain interrupt operation

   * @device_prep_slave_sg: prepares a slave dma operation

   * @device_prep_dma_cyclic: prepare a cyclic dma operation suitable for audio.
   *	The function takes a buffer of size buf_len. The callback function will
   *	be called after period_len bytes have been transferred.

   * @device_control: manipulate all pending operations on a channel, returns
   *	zero or error code

   * @device_tx_status: poll for transaction completion, the optional
   *	txstate parameter can be supplied with a pointer to get a

   *	struct with auxiliary transfer status information, otherwise the call

   *	will just return a simple status code

   * @device_issue_pending: push pending transactions to hardware

   */
  struct dma_device {
  
  	unsigned int chancnt;

  	unsigned int privatecnt;

  	struct list_head channels;
  	struct list_head global_node;

  	dma_cap_mask_t  cap_mask;

  	unsigned short max_xor;
  	unsigned short max_pq;

  	u8 copy_align;
  	u8 xor_align;
  	u8 pq_align;
  	u8 fill_align;

  	#define DMA_HAS_PQ_CONTINUE (1 << 15)

  	int dev_id;

  	struct device *dev;

  	int (*device_alloc_chan_resources)(struct dma_chan *chan);

  	void (*device_free_chan_resources)(struct dma_chan *chan);

  
  	struct dma_async_tx_descriptor *(*device_prep_dma_memcpy)(

  		struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,

  		size_t len, unsigned long flags);

  	struct dma_async_tx_descriptor *(*device_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 dma_async_tx_descriptor *(*device_prep_dma_xor_val)(

  		struct dma_chan *chan, dma_addr_t *src,	unsigned int src_cnt,

  		size_t len, enum sum_check_flags *result, unsigned long flags);

  	struct dma_async_tx_descriptor *(*device_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 dma_async_tx_descriptor *(*device_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 dma_async_tx_descriptor *(*device_prep_dma_memset)(

  		struct dma_chan *chan, dma_addr_t dest, int value, size_t len,

  		unsigned long flags);

  	struct dma_async_tx_descriptor *(*device_prep_dma_interrupt)(

  		struct dma_chan *chan, unsigned long flags);

  	struct dma_async_tx_descriptor *(*device_prep_dma_sg)(
  		struct dma_chan *chan,
  		struct scatterlist *dst_sg, unsigned int dst_nents,
  		struct scatterlist *src_sg, unsigned int src_nents,
  		unsigned long flags);

  	struct dma_async_tx_descriptor *(*device_prep_slave_sg)(
  		struct dma_chan *chan, struct scatterlist *sgl,
  		unsigned int sg_len, enum dma_data_direction direction,
  		unsigned long flags);

  	struct dma_async_tx_descriptor *(*device_prep_dma_cyclic)(
  		struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len,
  		size_t period_len, enum dma_data_direction direction);

  	int (*device_control)(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
  		unsigned long arg);

  	enum dma_status (*device_tx_status)(struct dma_chan *chan,
  					    dma_cookie_t cookie,
  					    struct dma_tx_state *txstate);

  	void (*device_issue_pending)(struct dma_chan *chan);

  };

  static inline int dmaengine_device_control(struct dma_chan *chan,
  					   enum dma_ctrl_cmd cmd,
  					   unsigned long arg)
  {
  	return chan->device->device_control(chan, cmd, arg);
  }
  
  static inline int dmaengine_slave_config(struct dma_chan *chan,
  					  struct dma_slave_config *config)
  {
  	return dmaengine_device_control(chan, DMA_SLAVE_CONFIG,
  			(unsigned long)config);
  }

  static inline struct dma_async_tx_descriptor *dmaengine_prep_slave_single(
  	struct dma_chan *chan, void *buf, size_t len,
  	enum dma_data_direction dir, unsigned long flags)
  {
  	struct scatterlist sg;
  	sg_init_one(&sg, buf, len);
  
  	return chan->device->device_prep_slave_sg(chan, &sg, 1, dir, flags);
  }

  static inline int dmaengine_terminate_all(struct dma_chan *chan)
  {
  	return dmaengine_device_control(chan, DMA_TERMINATE_ALL, 0);
  }
  
  static inline int dmaengine_pause(struct dma_chan *chan)
  {
  	return dmaengine_device_control(chan, DMA_PAUSE, 0);
  }
  
  static inline int dmaengine_resume(struct dma_chan *chan)
  {
  	return dmaengine_device_control(chan, DMA_RESUME, 0);
  }

  static inline dma_cookie_t dmaengine_submit(struct dma_async_tx_descriptor *desc)

  {
  	return desc->tx_submit(desc);
  }

  static inline bool dmaengine_check_align(u8 align, size_t off1, size_t off2, size_t len)
  {
  	size_t mask;
  
  	if (!align)
  		return true;
  	mask = (1 << align) - 1;
  	if (mask & (off1 | off2 | len))
  		return false;
  	return true;
  }
  
  static inline bool is_dma_copy_aligned(struct dma_device *dev, size_t off1,
  				       size_t off2, size_t len)
  {
  	return dmaengine_check_align(dev->copy_align, off1, off2, len);
  }
  
  static inline bool is_dma_xor_aligned(struct dma_device *dev, size_t off1,
  				      size_t off2, size_t len)
  {
  	return dmaengine_check_align(dev->xor_align, off1, off2, len);
  }
  
  static inline bool is_dma_pq_aligned(struct dma_device *dev, size_t off1,
  				     size_t off2, size_t len)
  {
  	return dmaengine_check_align(dev->pq_align, off1, off2, len);
  }
  
  static inline bool is_dma_fill_aligned(struct dma_device *dev, size_t off1,
  				       size_t off2, size_t len)
  {
  	return dmaengine_check_align(dev->fill_align, off1, off2, len);
  }

  static inline void
  dma_set_maxpq(struct dma_device *dma, int maxpq, int has_pq_continue)
  {
  	dma->max_pq = maxpq;
  	if (has_pq_continue)
  		dma->max_pq |= DMA_HAS_PQ_CONTINUE;
  }
  
  static inline bool dmaf_continue(enum dma_ctrl_flags flags)
  {
  	return (flags & DMA_PREP_CONTINUE) == DMA_PREP_CONTINUE;
  }
  
  static inline bool dmaf_p_disabled_continue(enum dma_ctrl_flags flags)
  {
  	enum dma_ctrl_flags mask = DMA_PREP_CONTINUE | DMA_PREP_PQ_DISABLE_P;
  
  	return (flags & mask) == mask;
  }
  
  static inline bool dma_dev_has_pq_continue(struct dma_device *dma)
  {
  	return (dma->max_pq & DMA_HAS_PQ_CONTINUE) == DMA_HAS_PQ_CONTINUE;
  }

  static inline unsigned short dma_dev_to_maxpq(struct dma_device *dma)

  {
  	return dma->max_pq & ~DMA_HAS_PQ_CONTINUE;
  }
  
  /* dma_maxpq - reduce maxpq in the face of continued operations
   * @dma - dma device with PQ capability
   * @flags - to check if DMA_PREP_CONTINUE and DMA_PREP_PQ_DISABLE_P are set
   *
   * When an engine does not support native continuation we need 3 extra
   * source slots to reuse P and Q with the following coefficients:
   * 1/ {00} * P : remove P from Q', but use it as a source for P'
   * 2/ {01} * Q : use Q to continue Q' calculation
   * 3/ {00} * Q : subtract Q from P' to cancel (2)
   *
   * In the case where P is disabled we only need 1 extra source:
   * 1/ {01} * Q : use Q to continue Q' calculation
   */
  static inline int dma_maxpq(struct dma_device *dma, enum dma_ctrl_flags flags)
  {
  	if (dma_dev_has_pq_continue(dma) || !dmaf_continue(flags))
  		return dma_dev_to_maxpq(dma);
  	else if (dmaf_p_disabled_continue(flags))
  		return dma_dev_to_maxpq(dma) - 1;
  	else if (dmaf_continue(flags))
  		return dma_dev_to_maxpq(dma) - 3;
  	BUG();
  }

  /* --- public DMA engine API --- */

  #ifdef CONFIG_DMA_ENGINE

  void dmaengine_get(void);
  void dmaengine_put(void);

  #else
  static inline void dmaengine_get(void)
  {
  }
  static inline void dmaengine_put(void)
  {
  }
  #endif

  #ifdef CONFIG_NET_DMA
  #define net_dmaengine_get()	dmaengine_get()
  #define net_dmaengine_put()	dmaengine_put()
  #else
  static inline void net_dmaengine_get(void)
  {
  }
  static inline void net_dmaengine_put(void)
  {
  }
  #endif

  #ifdef CONFIG_ASYNC_TX_DMA
  #define async_dmaengine_get()	dmaengine_get()
  #define async_dmaengine_put()	dmaengine_put()

  #ifndef CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH

  #define async_dma_find_channel(type) dma_find_channel(DMA_ASYNC_TX)
  #else

  #define async_dma_find_channel(type) dma_find_channel(type)

  #endif /* CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH */

  #else
  static inline void async_dmaengine_get(void)
  {
  }
  static inline void async_dmaengine_put(void)
  {
  }
  static inline struct dma_chan *
  async_dma_find_channel(enum dma_transaction_type type)
  {
  	return NULL;
  }

  #endif /* CONFIG_ASYNC_TX_DMA */

  dma_cookie_t dma_async_memcpy_buf_to_buf(struct dma_chan *chan,
  	void *dest, void *src, size_t len);
  dma_cookie_t dma_async_memcpy_buf_to_pg(struct dma_chan *chan,
  	struct page *page, unsigned int offset, void *kdata, size_t len);
  dma_cookie_t dma_async_memcpy_pg_to_pg(struct dma_chan *chan,
  	struct page *dest_pg, unsigned int dest_off, struct page *src_pg,
  	unsigned int src_off, size_t len);
  void dma_async_tx_descriptor_init(struct dma_async_tx_descriptor *tx,
  	struct dma_chan *chan);

  static inline void async_tx_ack(struct dma_async_tx_descriptor *tx)

  {

  	tx->flags |= DMA_CTRL_ACK;
  }

  static inline void async_tx_clear_ack(struct dma_async_tx_descriptor *tx)
  {
  	tx->flags &= ~DMA_CTRL_ACK;
  }

  static inline bool async_tx_test_ack(struct dma_async_tx_descriptor *tx)

  {

  	return (tx->flags & DMA_CTRL_ACK) == DMA_CTRL_ACK;

  }

  #define first_dma_cap(mask) __first_dma_cap(&(mask))
  static inline int __first_dma_cap(const dma_cap_mask_t *srcp)

  {

  	return min_t(int, DMA_TX_TYPE_END,
  		find_first_bit(srcp->bits, DMA_TX_TYPE_END));
  }

  #define next_dma_cap(n, mask) __next_dma_cap((n), &(mask))
  static inline int __next_dma_cap(int n, const dma_cap_mask_t *srcp)
  {
  	return min_t(int, DMA_TX_TYPE_END,
  		find_next_bit(srcp->bits, DMA_TX_TYPE_END, n+1));

  }

  #define dma_cap_set(tx, mask) __dma_cap_set((tx), &(mask))
  static inline void
  __dma_cap_set(enum dma_transaction_type tx_type, dma_cap_mask_t *dstp)

  {

  	set_bit(tx_type, dstp->bits);
  }

  #define dma_cap_clear(tx, mask) __dma_cap_clear((tx), &(mask))
  static inline void
  __dma_cap_clear(enum dma_transaction_type tx_type, dma_cap_mask_t *dstp)
  {
  	clear_bit(tx_type, dstp->bits);
  }

  #define dma_cap_zero(mask) __dma_cap_zero(&(mask))
  static inline void __dma_cap_zero(dma_cap_mask_t *dstp)
  {
  	bitmap_zero(dstp->bits, DMA_TX_TYPE_END);
  }

  #define dma_has_cap(tx, mask) __dma_has_cap((tx), &(mask))
  static inline int
  __dma_has_cap(enum dma_transaction_type tx_type, dma_cap_mask_t *srcp)
  {
  	return test_bit(tx_type, srcp->bits);

  }

  #define for_each_dma_cap_mask(cap, mask) \
  	for ((cap) = first_dma_cap(mask);	\
  		(cap) < DMA_TX_TYPE_END;	\
  		(cap) = next_dma_cap((cap), (mask)))

  /**

   * dma_async_issue_pending - flush pending transactions to HW

   * @chan: target DMA channel

   *
   * This allows drivers to push copies to HW in batches,
   * reducing MMIO writes where possible.
   */

  static inline void dma_async_issue_pending(struct dma_chan *chan)

  {

  	chan->device->device_issue_pending(chan);

  }

  #define dma_async_memcpy_issue_pending(chan) dma_async_issue_pending(chan)

  /**

   * dma_async_is_tx_complete - poll for transaction completion

   * @chan: DMA channel
   * @cookie: transaction identifier to check status of
   * @last: returns last completed cookie, can be NULL
   * @used: returns last issued cookie, can be NULL
   *
   * If @last and @used are passed in, upon return they reflect the driver
   * internal state and can be used with dma_async_is_complete() to check
   * the status of multiple cookies without re-checking hardware state.
   */

  static inline enum dma_status dma_async_is_tx_complete(struct dma_chan *chan,

  	dma_cookie_t cookie, dma_cookie_t *last, dma_cookie_t *used)
  {

  	struct dma_tx_state state;
  	enum dma_status status;
  
  	status = chan->device->device_tx_status(chan, cookie, &state);
  	if (last)
  		*last = state.last;
  	if (used)
  		*used = state.used;
  	return status;

  }

  #define dma_async_memcpy_complete(chan, cookie, last, used)\
  	dma_async_is_tx_complete(chan, cookie, last, used)

  /**
   * dma_async_is_complete - test a cookie against chan state
   * @cookie: transaction identifier to test status of
   * @last_complete: last know completed transaction
   * @last_used: last cookie value handed out
   *
   * dma_async_is_complete() is used in dma_async_memcpy_complete()

   * the test logic is separated for lightweight testing of multiple cookies

   */
  static inline enum dma_status dma_async_is_complete(dma_cookie_t cookie,
  			dma_cookie_t last_complete, dma_cookie_t last_used)
  {
  	if (last_complete <= last_used) {
  		if ((cookie <= last_complete) || (cookie > last_used))
  			return DMA_SUCCESS;
  	} else {
  		if ((cookie <= last_complete) && (cookie > last_used))
  			return DMA_SUCCESS;
  	}
  	return DMA_IN_PROGRESS;
  }

  static inline void
  dma_set_tx_state(struct dma_tx_state *st, dma_cookie_t last, dma_cookie_t used, u32 residue)
  {
  	if (st) {
  		st->last = last;
  		st->used = used;
  		st->residue = residue;
  	}
  }

  enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie);

  #ifdef CONFIG_DMA_ENGINE
  enum dma_status dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx);

  void dma_issue_pending_all(void);

  struct dma_chan *__dma_request_channel(dma_cap_mask_t *mask, dma_filter_fn fn, void *fn_param);
  void dma_release_channel(struct dma_chan *chan);

  #else
  static inline enum dma_status dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx)
  {
  	return DMA_SUCCESS;
  }

  static inline void dma_issue_pending_all(void)
  {

  }
  static inline struct dma_chan *__dma_request_channel(dma_cap_mask_t *mask,
  					      dma_filter_fn fn, void *fn_param)
  {
  	return NULL;
  }
  static inline void dma_release_channel(struct dma_chan *chan)
  {

  }

  #endif

  
  /* --- DMA device --- */
  
  int dma_async_device_register(struct dma_device *device);
  void dma_async_device_unregister(struct dma_device *device);

  void dma_run_dependencies(struct dma_async_tx_descriptor *tx);

  struct dma_chan *dma_find_channel(enum dma_transaction_type tx_type);

  #define dma_request_channel(mask, x, y) __dma_request_channel(&(mask), x, y)

  /* --- Helper iov-locking functions --- */
  
  struct dma_page_list {

  	char __user *base_address;

  	int nr_pages;
  	struct page **pages;
  };
  
  struct dma_pinned_list {
  	int nr_iovecs;
  	struct dma_page_list page_list[0];
  };
  
  struct dma_pinned_list *dma_pin_iovec_pages(struct iovec *iov, size_t len);
  void dma_unpin_iovec_pages(struct dma_pinned_list* pinned_list);
  
  dma_cookie_t dma_memcpy_to_iovec(struct dma_chan *chan, struct iovec *iov,
  	struct dma_pinned_list *pinned_list, unsigned char *kdata, size_t len);
  dma_cookie_t dma_memcpy_pg_to_iovec(struct dma_chan *chan, struct iovec *iov,
  	struct dma_pinned_list *pinned_list, struct page *page,
  	unsigned int offset, size_t len);

  #endif /* DMAENGINE_H */