/*
* 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.
*
* The full GNU General Public License is included in this distribution in the
* file called COPYING.
*/
#ifndef LINUX_DMAENGINE_H
#define LINUX_DMAENGINE_H
#include <linux/device.h>
#include <linux/err.h>
#include <linux/uio.h>
#include <linux/bug.h>
#include <linux/scatterlist.h>
#include <linux/bitmap.h>
#include <linux/types.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
static inline int dma_submit_error(dma_cookie_t cookie)
{
return cookie < 0 ? cookie : 0;
}
/**
* enum dma_status - DMA transaction status
* @DMA_COMPLETE: transaction completed
* @DMA_IN_PROGRESS: transaction not yet processed
* @DMA_PAUSED: transaction is paused
* @DMA_ERROR: transaction failed
*/
enum dma_status {
DMA_COMPLETE,
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_MEMSET_SG,
DMA_INTERRUPT,
DMA_SG,
DMA_PRIVATE,
DMA_ASYNC_TX,
DMA_SLAVE,
DMA_CYCLIC,
DMA_INTERLEAVE,
/* last transaction type for creation of the capabilities mask */
DMA_TX_TYPE_END,
};
/**
* enum dma_transfer_direction - dma transfer mode and direction indicator
* @DMA_MEM_TO_MEM: Async/Memcpy mode
* @DMA_MEM_TO_DEV: Slave mode & From Memory to Device
* @DMA_DEV_TO_MEM: Slave mode & From Device to Memory
* @DMA_DEV_TO_DEV: Slave mode & From Device to Device
*/
enum dma_transfer_direction {
DMA_MEM_TO_MEM,
DMA_MEM_TO_DEV,
DMA_DEV_TO_MEM,
DMA_DEV_TO_DEV,
DMA_TRANS_NONE,
};
/**
* Interleaved Transfer Request
* ----------------------------
* A chunk is collection of contiguous bytes to be transfered.
* The gap(in bytes) between two chunks is called inter-chunk-gap(ICG).
* ICGs may or maynot change between chunks.
* A FRAME is the smallest series of contiguous {chunk,icg} pairs,
* that when repeated an integral number of times, specifies the transfer.
* A transfer template is specification of a Frame, the number of times
* it is to be repeated and other per-transfer attributes.
*
* Practically, a client driver would have ready a template for each
* type of transfer it is going to need during its lifetime and
* set only 'src_start' and 'dst_start' before submitting the requests.
*
*
* | Frame-1 | Frame-2 | ~ | Frame-'numf' |
* |====....==.===...=...|====....==.===...=...| ~ |====....==.===...=...|
*
* == Chunk size
* ... ICG
*/
/**
* struct data_chunk - Element of scatter-gather list that makes a frame.
* @size: Number of bytes to read from source.
* size_dst := fn(op, size_src), so doesn't mean much for destination.
* @icg: Number of bytes to jump after last src/dst address of this
* chunk and before first src/dst address for next chunk.
* Ignored for dst(assumed 0), if dst_inc is true and dst_sgl is false.
* Ignored for src(assumed 0), if src_inc is true and src_sgl is false.
* @dst_icg: Number of bytes to jump after last dst address of this
* chunk and before the first dst address for next chunk.
* Ignored if dst_inc is true and dst_sgl is false.
* @src_icg: Number of bytes to jump after last src address of this
* chunk and before the first src address for next chunk.
* Ignored if src_inc is true and src_sgl is false.
*/
struct data_chunk {
size_t size;
size_t icg;
size_t dst_icg;
size_t src_icg;
};
/**
* struct dma_interleaved_template - Template to convey DMAC the transfer pattern
* and attributes.
* @src_start: Bus address of source for the first chunk.
* @dst_start: Bus address of destination for the first chunk.
* @dir: Specifies the type of Source and Destination.
* @src_inc: If the source address increments after reading from it.
* @dst_inc: If the destination address increments after writing to it.
* @src_sgl: If the 'icg' of sgl[] applies to Source (scattered read).
* Otherwise, source is read contiguously (icg ignored).
* Ignored if src_inc is false.
* @dst_sgl: If the 'icg' of sgl[] applies to Destination (scattered write).
* Otherwise, destination is filled contiguously (icg ignored).
* Ignored if dst_inc is false.
* @numf: Number of frames in this template.
* @frame_size: Number of chunks in a frame i.e, size of sgl[].
* @sgl: Array of {chunk,icg} pairs that make up a frame.
*/
struct dma_interleaved_template {
dma_addr_t src_start;
dma_addr_t dst_start;
enum dma_transfer_direction dir;
bool src_inc;
bool dst_inc;
bool src_sgl;
bool dst_sgl;
size_t numf;
size_t frame_size;
struct data_chunk sgl[0];
};
/**
* 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_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
* @DMA_CTRL_REUSE: client can reuse the descriptor and submit again till
* cleared or freed
*/
enum dma_ctrl_flags {
DMA_PREP_INTERRUPT = (1 << 0),
DMA_CTRL_ACK = (1 << 1),
DMA_PREP_PQ_DISABLE_P = (1 << 2),
DMA_PREP_PQ_DISABLE_Q = (1 << 3),
DMA_PREP_CONTINUE = (1 << 4),
DMA_PREP_FENCE = (1 << 5),
DMA_CTRL_REUSE = (1 << 6),
};
/**
* 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_router - DMA router structure
* @dev: pointer to the DMA router device
* @route_free: function to be called when the route can be disconnected
*/
struct dma_router {
struct device *dev;
void (*route_free)(struct device *dev, void *route_data);
};
/**
* 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
* @completed_cookie: last completed cookie for this channel
* @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
* @router: pointer to the DMA router structure
* @route_data: channel specific data for the router
* @private: private data for certain client-channel associations
*/
struct dma_chan {
struct dma_device *device;
dma_cookie_t cookie;
dma_cookie_t completed_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;
/* DMA router */
struct dma_router *router;
void *route_data;
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 width 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_3_BYTES = 3,
DMA_SLAVE_BUSWIDTH_4_BYTES = 4,
DMA_SLAVE_BUSWIDTH_8_BYTES = 8,
DMA_SLAVE_BUSWIDTH_16_BYTES = 16,
DMA_SLAVE_BUSWIDTH_32_BYTES = 32,
DMA_SLAVE_BUSWIDTH_64_BYTES = 64,
};
/**
* 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_MEM_TO_DEV and DMA_DEV_TO_MEM are
* legal values. DEPRECATED, drivers should use the direction argument
* to the device_prep_slave_sg and device_prep_dma_cyclic functions or
* the dir field in the dma_interleaved_template structure.
* @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.
* @src_port_window_size: The length of the register area in words the data need
* to be accessed on the device side. It is only used for devices which is using
* an area instead of a single register to receive the data. Typically the DMA
* loops in this area in order to transfer the data.
* @dst_port_window_size: same as src_port_window_size but for the destination
* port.
* @device_fc: Flow Controller Settings. Only valid for slave channels. Fill
* with 'true' if peripheral should be flow controller. Direction will be
* selected at Runtime.
* @slave_id: Slave requester id. Only valid for slave channels. The dma
* slave peripheral will have unique id as dma requester which need to be
* pass as slave config.
*
* 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
* callback in the dma_device structure, device_config and this struct
* will then be passed in as an argument to the function.
*
* The rationale for adding configuration information to this struct is as
* follows: if it is likely that more than one 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.
*/
struct dma_slave_config {
enum dma_transfer_direction direction;
phys_addr_t src_addr;
phys_addr_t dst_addr;
enum dma_slave_buswidth src_addr_width;
enum dma_slave_buswidth dst_addr_width;
u32 src_maxburst;
u32 dst_maxburst;
u32 src_port_window_size;
u32 dst_port_window_size;
bool device_fc;
unsigned int slave_id;
};
/**
* enum dma_residue_granularity - Granularity of the reported transfer residue
* @DMA_RESIDUE_GRANULARITY_DESCRIPTOR: Residue reporting is not support. The
* DMA channel is only able to tell whether a descriptor has been completed or
* not, which means residue reporting is not supported by this channel. The
* residue field of the dma_tx_state field will always be 0.
* @DMA_RESIDUE_GRANULARITY_SEGMENT: Residue is updated after each successfully
* completed segment of the transfer (For cyclic transfers this is after each
* period). This is typically implemented by having the hardware generate an
* interrupt after each transferred segment and then the drivers updates the
* outstanding residue by the size of the segment. Another possibility is if
* the hardware supports scatter-gather and the segment descriptor has a field
* which gets set after the segment has been completed. The driver then counts
* the number of segments without the flag set to compute the residue.
* @DMA_RESIDUE_GRANULARITY_BURST: Residue is updated after each transferred
* burst. This is typically only supported if the hardware has a progress
* register of some sort (E.g. a register with the current read/write address
* or a register with the amount of bursts/beats/bytes that have been
* transferred or still need to be transferred).
*/
enum dma_residue_granularity {
DMA_RESIDUE_GRANULARITY_DESCRIPTOR = 0,
DMA_RESIDUE_GRANULARITY_SEGMENT = 1,
DMA_RESIDUE_GRANULARITY_BURST = 2,
};
/* struct dma_slave_caps - expose capabilities of a slave channel only
*
* @src_addr_widths: bit mask of src addr widths the channel supports
* @dst_addr_widths: bit mask of dstn addr widths the channel supports
* @directions: bit mask of slave direction the channel supported
* since the enum dma_transfer_direction is not defined as bits for each
* type of direction, the dma controller should fill (1 << <TYPE>) and same
* should be checked by controller as well
* @max_burst: max burst capability per-transfer
* @cmd_pause: true, if pause and thereby resume is supported
* @cmd_terminate: true, if terminate cmd is supported
* @residue_granularity: granularity of the reported transfer residue
* @descriptor_reuse: if a descriptor can be reused by client and
* resubmitted multiple times
*/
struct dma_slave_caps {
u32 src_addr_widths;
u32 dst_addr_widths;
u32 directions;
u32 max_burst;
bool cmd_pause;
bool cmd_terminate;
enum dma_residue_granularity residue_granularity;
bool descriptor_reuse;
};
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);
enum dmaengine_tx_result {
DMA_TRANS_NOERROR = 0, /* SUCCESS */
DMA_TRANS_READ_FAILED, /* Source DMA read failed */
DMA_TRANS_WRITE_FAILED, /* Destination DMA write failed */
DMA_TRANS_ABORTED, /* Op never submitted / aborted */
};
struct dmaengine_result {
enum dmaengine_tx_result result;
u32 residue;
};
typedef void (*dma_async_tx_callback_result)(void *dma_async_param,
const struct dmaengine_result *result);
struct dmaengine_unmap_data {
u8 map_cnt;
u8 to_cnt;
u8 from_cnt;
u8 bidi_cnt;
struct device *dev;
struct kref kref;
size_t len;
dma_addr_t addr[0];
};
/**
* 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: accept the descriptor, assign ordered cookie and mark the
* descriptor pending. To be pushed on .issue_pending() call
* @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);
int (*desc_free)(struct dma_async_tx_descriptor *tx);
dma_async_tx_callback callback;
dma_async_tx_callback_result callback_result;
void *callback_param;
struct dmaengine_unmap_data *unmap;
#ifdef [31mCONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH[0m
struct dma_async_tx_descriptor *next;
struct dma_async_tx_descriptor *parent;
spinlock_t lock;
#endif
};
#ifdef [31mCONFIG_DMA_ENGINE[0m
static inline void dma_set_unmap(struct dma_async_tx_descriptor *tx,
struct dmaengine_unmap_data *unmap)
{
kref_get(&unmap->kref);
tx->unmap = unmap;
}
struct dmaengine_unmap_data *
dmaengine_get_unmap_data(struct device *dev, int nr, gfp_t flags);
void dmaengine_unmap_put(struct dmaengine_unmap_data *unmap);
#else
static inline void dma_set_unmap(struct dma_async_tx_descriptor *tx,
struct dmaengine_unmap_data *unmap)
{
}
static inline struct dmaengine_unmap_data *
dmaengine_get_unmap_data(struct device *dev, int nr, gfp_t flags)
{
return NULL;
}
static inline void dmaengine_unmap_put(struct dmaengine_unmap_data *unmap)
{
}
#endif
static inline void dma_descriptor_unmap(struct dma_async_tx_descriptor *tx)
{
if (tx->unmap) {
dmaengine_unmap_put(tx->unmap);
tx->unmap = NULL;
}
}
#ifndef [31mCONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH[0m
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;
};
/**
* enum dmaengine_alignment - defines alignment of the DMA async tx
* buffers
*/
enum dmaengine_alignment {
DMAENGINE_ALIGN_1_BYTE = 0,
DMAENGINE_ALIGN_2_BYTES = 1,
DMAENGINE_ALIGN_4_BYTES = 2,
DMAENGINE_ALIGN_8_BYTES = 3,
DMAENGINE_ALIGN_16_BYTES = 4,
DMAENGINE_ALIGN_32_BYTES = 5,
DMAENGINE_ALIGN_64_BYTES = 6,
};
/**
* struct dma_slave_map - associates slave device and it's slave channel with
* parameter to be used by a filter function
* @devname: name of the device
* @slave: slave channel name
* @param: opaque parameter to pass to struct dma_filter.fn
*/
struct dma_slave_map {
const char *devname;
const char *slave;
void *param;
};
/**
* struct dma_filter - information for slave device/channel to filter_fn/param
* mapping
* @fn: filter function callback
* @mapcnt: number of slave device/channel in the map
* @map: array of channel to filter mapping data
*/
struct dma_filter {
dma_filter_fn fn;
int mapcnt;
const struct dma_slave_map *map;
};
/**
* 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
* @filter: information for device/slave to filter function/param mapping
* @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
* @src_addr_widths: bit mask of src addr widths the device supports
* @dst_addr_widths: bit mask of dst addr widths the device supports
* @directions: bit mask of slave direction the device supports since
* the enum dma_transfer_direction is not defined as bits for
* each type of direction, the dma controller should fill (1 <<
* <TYPE>) and same should be checked by controller as well
* @max_burst: max burst capability per-transfer
* @residue_granularity: granularity of the transfer residue reported
* by tx_status
* @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_memset_sg: prepares a memset operation over a scatter list
* @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_prep_interleaved_dma: Transfer expression in a generic way.
* @device_prep_dma_imm_data: DMA's 8 byte immediate data to the dst address
* @device_config: Pushes a new configuration to a channel, return 0 or an error
* code
* @device_pause: Pauses any transfer happening on a channel. Returns
* 0 or an error code
* @device_resume: Resumes any transfer on a channel previously
* paused. Returns 0 or an error code
* @device_terminate_all: Aborts all transfers on a channel. Returns 0
* or an error code
* @device_synchronize: Synchronizes the termination of a transfers to the
* current context.
* @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
* @descriptor_reuse: a submitted transfer can be resubmitted after completion
*/
struct dma_device {
unsigned int chancnt;
unsigned int privatecnt;
struct list_head channels;
struct list_head global_node;
struct dma_filter filter;
dma_cap_mask_t cap_mask;
unsigned short max_xor;
unsigned short max_pq;
enum dmaengine_alignment copy_align;
enum dmaengine_alignment xor_align;
enum dmaengine_alignment pq_align;
enum dmaengine_alignment fill_align;
#define DMA_HAS_PQ_CONTINUE (1 << 15)
int dev_id;
struct device *dev;
u32 src_addr_widths;
u32 dst_addr_widths;
u32 directions;
u32 max_burst;
bool descriptor_reuse;
enum dma_residue_granularity residue_granularity;
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 dst, 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 dst, 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_memset_sg)(
struct dma_chan *chan, struct scatterlist *sg,
unsigned int nents, int value, 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_transfer_direction direction,
unsigned long flags, void *context);
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_transfer_direction direction,
unsigned long flags);
struct dma_async_tx_descriptor *(*device_prep_interleaved_dma)(
struct dma_chan *chan, struct dma_interleaved_template *xt,
unsigned long flags);
struct dma_async_tx_descriptor *(*device_prep_dma_imm_data)(
struct dma_chan *chan, dma_addr_t dst, u64 data,
unsigned long flags);
int (*device_config)(struct dma_chan *chan,
struct dma_slave_config *config);
int (*device_pause)(struct dma_chan *chan);
int (*device_resume)(struct dma_chan *chan);
int (*device_terminate_all)(struct dma_chan *chan);
void (*device_synchronize)(struct dma_chan *chan);
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_slave_config(struct dma_chan *chan,
struct dma_slave_config *config)
{
if (chan->device->device_config)
return chan->device->device_config(chan, config);
return -ENOSYS;
}
static inline bool is_slave_direction(enum dma_transfer_direction direction)
{
return (direction == DMA_MEM_TO_DEV) || (direction == DMA_DEV_TO_MEM);
}
static inline struct dma_async_tx_descriptor *dmaengine_prep_slave_single(
struct dma_chan *chan, dma_addr_t buf, size_t len,
enum dma_transfer_direction dir, unsigned long flags)
{
struct scatterlist sg;
sg_init_table(&sg, 1);
sg_dma_address(&sg) = buf;
sg_dma_len(&sg) = len;
if (!chan || !chan->device || !chan->device->device_prep_slave_sg)
return NULL;
return chan->device->device_prep_slave_sg(chan, &sg, 1,
dir, flags, NULL);
}
static inline struct dma_async_tx_descriptor *dmaengine_prep_slave_sg(
struct dma_chan *chan, struct scatterlist *sgl, unsigned int sg_len,
enum dma_transfer_direction dir, unsigned long flags)
{
if (!chan || !chan->device || !chan->device->device_prep_slave_sg)
return NULL;
return chan->device->device_prep_slave_sg(chan, sgl, sg_len,
dir, flags, NULL);
}
#ifdef [31mCONFIG_RAPIDIO_DMA_ENGINE[0m
struct rio_dma_ext;
static inline struct dma_async_tx_descriptor *dmaengine_prep_rio_sg(
struct dma_chan *chan, struct scatterlist *sgl, unsigned int sg_len,
enum dma_transfer_direction dir, unsigned long flags,
struct rio_dma_ext *rio_ext)
{
if (!chan || !chan->device || !chan->device->device_prep_slave_sg)
return NULL;
return chan->device->device_prep_slave_sg(chan, sgl, sg_len,
dir, flags, rio_ext);
}
#endif
static inline struct dma_async_tx_descriptor *dmaengine_prep_dma_cyclic(
struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len,
size_t period_len, enum dma_transfer_direction dir,
unsigned long flags)
{
if (!chan || !chan->device || !chan->device->device_prep_dma_cyclic)
return NULL;
return chan->device->device_prep_dma_cyclic(chan, buf_addr, buf_len,
period_len, dir, flags);
}
static inline struct dma_async_tx_descriptor *dmaengine_prep_interleaved_dma(
struct dma_chan *chan, struct dma_interleaved_template *xt,
unsigned long flags)
{
if (!chan || !chan->device || !chan->device->device_prep_interleaved_dma)
return NULL;
return chan->device->device_prep_interleaved_dma(chan, xt, flags);
}
static inline struct dma_async_tx_descriptor *dmaengine_prep_dma_memset(
struct dma_chan *chan, dma_addr_t dest, int value, size_t len,
unsigned long flags)
{
if (!chan || !chan->device || !chan->device->device_prep_dma_memset)
return NULL;
return chan->device->device_prep_dma_memset(chan, dest, value,
len, flags);
}
static inline struct dma_async_tx_descriptor *dmaengine_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)
{
if (!chan || !chan->device || !chan->device->device_prep_dma_sg)
return NULL;
return chan->device->device_prep_dma_sg(chan, dst_sg, dst_nents,
src_sg, src_nents, flags);
}
/**
* dmaengine_terminate_all() - Terminate all active DMA transfers
* @chan: The channel for which to terminate the transfers
*
* This function is DEPRECATED use either dmaengine_terminate_sync() or
* dmaengine_terminate_async() instead.
*/
static inline int dmaengine_terminate_all(struct dma_chan *chan)
{
if (chan->device->device_terminate_all)
return chan->device->device_terminate_all(chan);
return -ENOSYS;
}
/**
* dmaengine_terminate_async() - Terminate all active DMA transfers
* @chan: The channel for which to terminate the transfers
*
* Calling this function will terminate all active and pending descriptors
* that have previously been submitted to the channel. It is not guaranteed
* though that the transfer for the active descriptor has stopped when the
* function returns. Furthermore it is possible the complete callback of a
* submitted transfer is still running when this function returns.
*
* dmaengine_synchronize() needs to be called before it is safe to free
* any memory that is accessed by previously submitted descriptors or before
* freeing any resources accessed from within the completion callback of any
* perviously submitted descriptors.
*
* This function can be called from atomic context as well as from within a
* complete callback of a descriptor submitted on the same channel.
*
* If none of the two conditions above apply consider using
* dmaengine_terminate_sync() instead.
*/
static inline int dmaengine_terminate_async(struct dma_chan *chan)
{
if (chan->device->device_terminate_all)
return chan->device->device_terminate_all(chan);
return -EINVAL;
}
/**
* dmaengine_synchronize() - Synchronize DMA channel termination
* @chan: The channel to synchronize
*
* Synchronizes to the DMA channel termination to the current context. When this
* function returns it is guaranteed that all transfers for previously issued
* descriptors have stopped and and it is safe to free the memory assoicated
* with them. Furthermore it is guaranteed that all complete callback functions
* for a previously submitted descriptor have finished running and it is safe to
* free resources accessed from within the complete callbacks.
*
* The behavior of this function is undefined if dma_async_issue_pending() has
* been called between dmaengine_terminate_async() and this function.
*
* This function must only be called from non-atomic context and must not be
* called from within a complete callback of a descriptor submitted on the same
* channel.
*/
static inline void dmaengine_synchronize(struct dma_chan *chan)
{
might_sleep();
if (chan->device->device_synchronize)
chan->device->device_synchronize(chan);
}
/**
* dmaengine_terminate_sync() - Terminate all active DMA transfers
* @chan: The channel for which to terminate the transfers
*
* Calling this function will terminate all active and pending transfers
* that have previously been submitted to the channel. It is similar to
* dmaengine_terminate_async() but guarantees that the DMA transfer has actually
* stopped and that all complete callbacks have finished running when the
* function returns.
*
* This function must only be called from non-atomic context and must not be
* called from within a complete callback of a descriptor submitted on the same
* channel.
*/
static inline int dmaengine_terminate_sync(struct dma_chan *chan)
{
int ret;
ret = dmaengine_terminate_async(chan);
if (ret)
return ret;
dmaengine_synchronize(chan);
return 0;
}
static inline int dmaengine_pause(struct dma_chan *chan)
{
if (chan->device->device_pause)
return chan->device->device_pause(chan);
return -ENOSYS;
}
static inline int dmaengine_resume(struct dma_chan *chan)
{
if (chan->device->device_resume)
return chan->device->device_resume(chan);
return -ENOSYS;
}
static inline enum dma_status dmaengine_tx_status(struct dma_chan *chan,
dma_cookie_t cookie, struct dma_tx_state *state)
{
return chan->device->device_tx_status(chan, cookie, state);
}
static inline dma_cookie_t dmaengine_submit(struct dma_async_tx_descriptor *desc)
{
return desc->tx_submit(desc);
}
static inline bool dmaengine_check_align(enum dmaengine_alignment 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();
}
static inline size_t dmaengine_get_icg(bool inc, bool sgl, size_t icg,
size_t dir_icg)
{
if (inc) {
if (dir_icg)
return dir_icg;
else if (sgl)
return icg;
}
return 0;
}
static inline size_t dmaengine_get_dst_icg(struct dma_interleaved_template *xt,
struct data_chunk *chunk)
{
return dmaengine_get_icg(xt->dst_inc, xt->dst_sgl,
chunk->icg, chunk->dst_icg);
}
static inline size_t dmaengine_get_src_icg(struct dma_interleaved_template *xt,
struct data_chunk *chunk)
{
return dmaengine_get_icg(xt->src_inc, xt->src_sgl,
chunk->icg, chunk->src_icg);
}
/* --- public DMA engine API --- */
#ifdef [31mCONFIG_DMA_ENGINE[0m
void dmaengine_get(void);
void dmaengine_put(void);
#else
static inline void dmaengine_get(void)
{
}
static inline void dmaengine_put(void)
{
}
#endif
#ifdef [31mCONFIG_ASYNC_TX_DMA[0m
#define async_dmaengine_get() dmaengine_get()
#define async_dmaengine_put() dmaengine_put()
#ifndef [31mCONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH[0m
#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 */
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 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_each_set_bit(cap, mask.bits, DMA_TX_TYPE_END)
/**
* 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);
}
/**
* 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;
}
/**
* 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_is_tx_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_COMPLETE;
} else {
if ((cookie <= last_complete) && (cookie > last_used))
return DMA_COMPLETE;
}
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;
}
}
#ifdef [31mCONFIG_DMA_ENGINE[0m
struct dma_chan *dma_find_channel(enum dma_transaction_type tx_type);
enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie);
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(const dma_cap_mask_t *mask,
dma_filter_fn fn, void *fn_param);
struct dma_chan *dma_request_slave_channel(struct device *dev, const char *name);
struct dma_chan *dma_request_chan(struct device *dev, const char *name);
struct dma_chan *dma_request_chan_by_mask(const dma_cap_mask_t *mask);
void dma_release_channel(struct dma_chan *chan);
int dma_get_slave_caps(struct dma_chan *chan, struct dma_slave_caps *caps);
#else
static inline struct dma_chan *dma_find_channel(enum dma_transaction_type tx_type)
{
return NULL;
}
static inline enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie)
{
return DMA_COMPLETE;
}
static inline enum dma_status dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx)
{
return DMA_COMPLETE;
}
static inline void dma_issue_pending_all(void)
{
}
static inline struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
dma_filter_fn fn, void *fn_param)
{
return NULL;
}
static inline struct dma_chan *dma_request_slave_channel(struct device *dev,
const char *name)
{
return NULL;
}
static inline struct dma_chan *dma_request_chan(struct device *dev,
const char *name)
{
return ERR_PTR(-ENODEV);
}
static inline struct dma_chan *dma_request_chan_by_mask(
const dma_cap_mask_t *mask)
{
return ERR_PTR(-ENODEV);
}
static inline void dma_release_channel(struct dma_chan *chan)
{
}
static inline int dma_get_slave_caps(struct dma_chan *chan,
struct dma_slave_caps *caps)
{
return -ENXIO;
}
#endif
#define dma_request_slave_channel_reason(dev, name) dma_request_chan(dev, name)
static inline int dmaengine_desc_set_reuse(struct dma_async_tx_descriptor *tx)
{
struct dma_slave_caps caps;
dma_get_slave_caps(tx->chan, &caps);
if (caps.descriptor_reuse) {
tx->flags |= DMA_CTRL_REUSE;
return 0;
} else {
return -EPERM;
}
}
static inline void dmaengine_desc_clear_reuse(struct dma_async_tx_descriptor *tx)
{
tx->flags &= ~DMA_CTRL_REUSE;
}
static inline bool dmaengine_desc_test_reuse(struct dma_async_tx_descriptor *tx)
{
return (tx->flags & DMA_CTRL_REUSE) == DMA_CTRL_REUSE;
}
static inline int dmaengine_desc_free(struct dma_async_tx_descriptor *desc)
{
/* this is supported for reusable desc, so check that */
if (dmaengine_desc_test_reuse(desc))
return desc->desc_free(desc);
else
return -EPERM;
}
/* --- 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_get_slave_channel(struct dma_chan *chan);
struct dma_chan *dma_get_any_slave_channel(struct dma_device *device);
#define dma_request_channel(mask, x, y) __dma_request_channel(&(mask), x, y)
#define dma_request_slave_channel_compat(mask, x, y, dev, name) \
__dma_request_slave_channel_compat(&(mask), x, y, dev, name)
static inline struct dma_chan
*__dma_request_slave_channel_compat(const dma_cap_mask_t *mask,
dma_filter_fn fn, void *fn_param,
struct device *dev, const char *name)
{
struct dma_chan *chan;
chan = dma_request_slave_channel(dev, name);
if (chan)
return chan;
if (!fn || !fn_param)
return NULL;
return __dma_request_channel(mask, fn, fn_param);
}
#endif /* DMAENGINE_H */