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| author | Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com> | 2009-04-01 15:47:02 +0200 |
|---|---|---|
| committer | Dan Williams <dan.j.williams@intel.com> | 2009-04-01 15:42:34 -0700 |
| commit | d9de451989a88a2003ca06e524aca4665c0c7f06 (patch) | |
| tree | a926d4ff1b73da88d5112324611a579a94e28095 /include/linux/dw_dmac.h | |
| parent | 0f571515c332e00b3515dbe0859ceaa30ab66e00 (diff) | |
| download | lwn-d9de451989a88a2003ca06e524aca4665c0c7f06.tar.gz lwn-d9de451989a88a2003ca06e524aca4665c0c7f06.zip | |
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>
Diffstat (limited to 'include/linux/dw_dmac.h')
| -rw-r--r-- | include/linux/dw_dmac.h | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/include/linux/dw_dmac.h b/include/linux/dw_dmac.h index d797dde247f7..c8aad713a046 100644 --- a/include/linux/dw_dmac.h +++ b/include/linux/dw_dmac.h @@ -74,4 +74,23 @@ struct dw_dma_slave { #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 */ |