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linux-next/include/linux/platform_data/dma-s3c24xx.h
Sam Van Den Berge 34681d84a0 dmaengine: s3c24xx: Add dma_slave_map for s3c2440 devices
This patch updates the s3c24xx dma driver to be able to pass a
dma_slave_map array via the platform data. This is needed to
be able to use the new, simpler dmaengine API [1].
I used the virtual DMA channels as a parameter for the dma_filter
function. By doing that, I could reuse the existing filter function in
drivers/dma/s3c24xx-dma.c.

I have tested this on my mini2440 board with the audio driver.
According to my observations, dma_request_slave_channel in the
function dmaengine_pcm_new in the file
sound/soc/soc-generic-dmaengine-pcm.c now returns a valid DMA channel
whereas before no DMA channel was returned at that point.

Entries for DMACH_XD0, DMACH_XD1 and DMACH_TIMER are missing because I
don't realy know which driver to use for these.

[1]
http://lists.infradead.org/pipermail/linux-arm-kernel/2015-December/393635.html

Signed-off-by: Sam Van Den Berge <sam.van.den.berge@telenet.be>
Reviewed-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2016-09-26 23:13:04 +05:30

53 lines
1.5 KiB
C

/*
* S3C24XX DMA handling
*
* Copyright (c) 2013 Heiko Stuebner <heiko@sntech.de>
*
* 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.
*/
/* Helper to encode the source selection constraints for early s3c socs. */
#define S3C24XX_DMA_CHANREQ(src, chan) ((BIT(3) | src) << chan * 4)
enum s3c24xx_dma_bus {
S3C24XX_DMA_APB,
S3C24XX_DMA_AHB,
};
/**
* @bus: on which bus does the peripheral reside - AHB or APB.
* @handshake: is a handshake with the peripheral necessary
* @chansel: channel selection information, depending on variant; reqsel for
* s3c2443 and later and channel-selection map for earlier SoCs
* see CHANSEL doc in s3c2443-dma.c
*/
struct s3c24xx_dma_channel {
enum s3c24xx_dma_bus bus;
bool handshake;
u16 chansel;
};
struct dma_slave_map;
/**
* struct s3c24xx_dma_platdata - platform specific settings
* @num_phy_channels: number of physical channels
* @channels: array of virtual channel descriptions
* @num_channels: number of virtual channels
* @slave_map: dma slave map matching table
* @slavecnt: number of elements in slave_map
*/
struct s3c24xx_dma_platdata {
int num_phy_channels;
struct s3c24xx_dma_channel *channels;
int num_channels;
const struct dma_slave_map *slave_map;
int slavecnt;
};
struct dma_chan;
bool s3c24xx_dma_filter(struct dma_chan *chan, void *param);