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/* SPDX-License-Identifier: GPL-2.0
* Dmaengine driver base library for DMA controllers, found on SH-based SoCs
* extracted from shdma.c and headers
* Copyright (C) 2011-2012 Guennadi Liakhovetski <>
* Copyright (C) 2009 Nobuhiro Iwamatsu <>
* Copyright (C) 2009 Renesas Solutions, Inc. All rights reserved.
* Copyright (C) 2007 Freescale Semiconductor, Inc. All rights reserved.
#ifndef SHDMA_BASE_H
#define SHDMA_BASE_H
#include <linux/dmaengine.h>
#include <linux/interrupt.h>
#include <linux/list.h>
#include <linux/types.h>
* shdma_pm_state - DMA channel PM state
* SHDMA_PM_ESTABLISHED: either idle or during data transfer
* SHDMA_PM_BUSY: during the transfer preparation, when we have to
* drop the lock temporarily
* SHDMA_PM_PENDING: transfers pending
enum shdma_pm_state {
struct device;
* Drivers, using this library are expected to embed struct shdma_dev,
* struct shdma_chan, struct shdma_desc, and struct shdma_slave
* in their respective device, channel, descriptor and slave objects.
struct shdma_slave {
int slave_id;
struct shdma_desc {
struct list_head node;
struct dma_async_tx_descriptor async_tx;
enum dma_transfer_direction direction;
size_t partial;
dma_cookie_t cookie;
int chunks;
int mark;
bool cyclic; /* used as cyclic transfer */
struct shdma_chan {
spinlock_t chan_lock; /* Channel operation lock */
struct list_head ld_queue; /* Link descriptors queue */
struct list_head ld_free; /* Free link descriptors */
struct dma_chan dma_chan; /* DMA channel */
struct device *dev; /* Channel device */
void *desc; /* buffer for descriptor array */
int desc_num; /* desc count */
size_t max_xfer_len; /* max transfer length */
int id; /* Raw id of this channel */
int irq; /* Channel IRQ */
int slave_id; /* Client ID for slave DMA */
int real_slave_id; /* argument passed to filter function */
int hw_req; /* DMA request line for slave DMA - same
* as MID/RID, used with DT */
enum shdma_pm_state pm_state;
* struct shdma_ops - simple DMA driver operations
* desc_completed: return true, if this is the descriptor, that just has
* completed (atomic)
* halt_channel: stop DMA channel operation (atomic)
* channel_busy: return true, if the channel is busy (atomic)
* slave_addr: return slave DMA address
* desc_setup: set up the hardware specific descriptor portion (atomic)
* set_slave: bind channel to a slave
* setup_xfer: configure channel hardware for operation (atomic)
* start_xfer: start the DMA transfer (atomic)
* embedded_desc: return Nth struct shdma_desc pointer from the
* descriptor array
* chan_irq: process channel IRQ, return true if a transfer has
* completed (atomic)
struct shdma_ops {
bool (*desc_completed)(struct shdma_chan *, struct shdma_desc *);
void (*halt_channel)(struct shdma_chan *);
bool (*channel_busy)(struct shdma_chan *);
dma_addr_t (*slave_addr)(struct shdma_chan *);
int (*desc_setup)(struct shdma_chan *, struct shdma_desc *,
dma_addr_t, dma_addr_t, size_t *);
int (*set_slave)(struct shdma_chan *, int, dma_addr_t, bool);
void (*setup_xfer)(struct shdma_chan *, int);
void (*start_xfer)(struct shdma_chan *, struct shdma_desc *);
struct shdma_desc *(*embedded_desc)(void *, int);
bool (*chan_irq)(struct shdma_chan *, int);
size_t (*get_partial)(struct shdma_chan *, struct shdma_desc *);
struct shdma_dev {
struct dma_device dma_dev;
struct shdma_chan **schan;
const struct shdma_ops *ops;
size_t desc_size;
#define shdma_for_each_chan(c, d, i) for (i = 0, c = (d)->schan[0]; \
i < (d)->dma_dev.chancnt; c = (d)->schan[++i])
int shdma_request_irq(struct shdma_chan *, int,
unsigned long, const char *);
bool shdma_reset(struct shdma_dev *sdev);
void shdma_chan_probe(struct shdma_dev *sdev,
struct shdma_chan *schan, int id);
void shdma_chan_remove(struct shdma_chan *schan);
int shdma_init(struct device *dev, struct shdma_dev *sdev,
int chan_num);
void shdma_cleanup(struct shdma_dev *sdev);
bool shdma_chan_filter(struct dma_chan *chan, void *arg);
static inline bool shdma_chan_filter(struct dma_chan *chan, void *arg)
return false;