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linux-next/include/linux/dw_dmac.h
Hans-Christian Egtvedt d9de451989 dw_dmac: add cyclic API to DW DMA driver
This patch adds a cyclic DMA interface to the DW DMA driver. This is
very useful if you want to use the DMA controller in combination with a
sound device which uses cyclic buffers.

Using a DMA channel for cyclic DMA will disable the possibility to use
it as a normal DMA engine until the user calls the cyclic free function
on the DMA channel. Also a cyclic DMA list can not be prepared if the
channel is already active.

Signed-off-by: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>
Acked-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-04-01 15:42:34 -07:00

97 lines
3.0 KiB
C

/*
* Driver for the Synopsys DesignWare DMA Controller (aka DMACA on
* AVR32 systems.)
*
* Copyright (C) 2007 Atmel Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#ifndef DW_DMAC_H
#define DW_DMAC_H
#include <linux/dmaengine.h>
/**
* struct dw_dma_platform_data - Controller configuration parameters
* @nr_channels: Number of channels supported by hardware (max 8)
*/
struct dw_dma_platform_data {
unsigned int nr_channels;
};
/**
* enum dw_dma_slave_width - DMA slave register access width.
* @DMA_SLAVE_WIDTH_8BIT: Do 8-bit slave register accesses
* @DMA_SLAVE_WIDTH_16BIT: Do 16-bit slave register accesses
* @DMA_SLAVE_WIDTH_32BIT: Do 32-bit slave register accesses
*/
enum dw_dma_slave_width {
DW_DMA_SLAVE_WIDTH_8BIT,
DW_DMA_SLAVE_WIDTH_16BIT,
DW_DMA_SLAVE_WIDTH_32BIT,
};
/**
* struct dw_dma_slave - Controller-specific information about a slave
*
* @dma_dev: required DMA master device
* @tx_reg: physical address of data register used for
* memory-to-peripheral transfers
* @rx_reg: physical address of data register used for
* peripheral-to-memory transfers
* @reg_width: peripheral register width
* @cfg_hi: Platform-specific initializer for the CFG_HI register
* @cfg_lo: Platform-specific initializer for the CFG_LO register
*/
struct dw_dma_slave {
struct device *dma_dev;
dma_addr_t tx_reg;
dma_addr_t rx_reg;
enum dw_dma_slave_width reg_width;
u32 cfg_hi;
u32 cfg_lo;
};
/* Platform-configurable bits in CFG_HI */
#define DWC_CFGH_FCMODE (1 << 0)
#define DWC_CFGH_FIFO_MODE (1 << 1)
#define DWC_CFGH_PROTCTL(x) ((x) << 2)
#define DWC_CFGH_SRC_PER(x) ((x) << 7)
#define DWC_CFGH_DST_PER(x) ((x) << 11)
/* Platform-configurable bits in CFG_LO */
#define DWC_CFGL_PRIO(x) ((x) << 5) /* priority */
#define DWC_CFGL_LOCK_CH_XFER (0 << 12) /* scope of LOCK_CH */
#define DWC_CFGL_LOCK_CH_BLOCK (1 << 12)
#define DWC_CFGL_LOCK_CH_XACT (2 << 12)
#define DWC_CFGL_LOCK_BUS_XFER (0 << 14) /* scope of LOCK_BUS */
#define DWC_CFGL_LOCK_BUS_BLOCK (1 << 14)
#define DWC_CFGL_LOCK_BUS_XACT (2 << 14)
#define DWC_CFGL_LOCK_CH (1 << 15) /* channel lockout */
#define DWC_CFGL_LOCK_BUS (1 << 16) /* busmaster lockout */
#define DWC_CFGL_HS_DST_POL (1 << 18) /* dst handshake active low */
#define DWC_CFGL_HS_SRC_POL (1 << 19) /* src handshake active low */
/* DMA API extensions */
struct dw_cyclic_desc {
struct dw_desc **desc;
unsigned long periods;
void (*period_callback)(void *param);
void *period_callback_param;
};
struct dw_cyclic_desc *dw_dma_cyclic_prep(struct dma_chan *chan,
dma_addr_t buf_addr, size_t buf_len, size_t period_len,
enum dma_data_direction direction);
void dw_dma_cyclic_free(struct dma_chan *chan);
int dw_dma_cyclic_start(struct dma_chan *chan);
void dw_dma_cyclic_stop(struct dma_chan *chan);
dma_addr_t dw_dma_get_src_addr(struct dma_chan *chan);
dma_addr_t dw_dma_get_dst_addr(struct dma_chan *chan);
#endif /* DW_DMAC_H */