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authorHans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>2009-04-01 15:47:02 +0200
committerDan Williams <dan.j.williams@intel.com>2009-04-01 15:42:34 -0700
commitd9de451989a88a2003ca06e524aca4665c0c7f06 (patch)
treea926d4ff1b73da88d5112324611a579a94e28095 /include/linux/dw_dmac.h
parent0f571515c332e00b3515dbe0859ceaa30ab66e00 (diff)
downloadop-kernel-dev-d9de451989a88a2003ca06e524aca4665c0c7f06.zip
op-kernel-dev-d9de451989a88a2003ca06e524aca4665c0c7f06.tar.gz
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.h19
1 files changed, 19 insertions, 0 deletions
diff --git a/include/linux/dw_dmac.h b/include/linux/dw_dmac.h
index d797dde..c8aad71 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 */
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