Messages in this thread Patch in this message | | | Date | Sat, 01 Sep 2012 11:05:34 +0800 | From | Hein Tibosch <> | Subject | [PATCH v3 2/3] dw_dmac: max_mem_width limits value for SRC/DST_TR_WID register |
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The dw_dmac driver was earlier adapted to do 64-bit transfers on the memory side (see https://lkml.org/lkml/2012/1/18/52) This works on ARM platforms but for AVR32 (AP700x) the maximum allowed transfer size is 32-bits. This patch allows the arch code to set a new slave property max_mem_width to limit the size.
Allowable values are:
#define DW_MEM_WIDTH_64 0 /* default */ #define DW_MEM_WIDTH_32 1 /* e.g. for avr32 */
Signed-off-by: Hein Tibosch <hein_tibosch@yahoo.es> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> --- drivers/dma/dw_dmac.c | 10 +++++++--- include/linux/dw_dmac.h | 3 +++ 2 files changed, 10 insertions(+), 3 deletions(-)
diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c index 7212961..11f8542 100644 --- a/drivers/dma/dw_dmac.c +++ b/drivers/dma/dw_dmac.c @@ -618,6 +618,7 @@ dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src, size_t len, unsigned long flags) { struct dw_dma_chan *dwc = to_dw_dma_chan(chan); + struct dw_dma_slave *dws = chan->private; struct dw_desc *desc; struct dw_desc *first; struct dw_desc *prev; @@ -639,7 +640,8 @@ dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src, * We can be a lot more clever here, but this should take care * of the most common optimization. */ - if (!((src | dest | len) & 7)) + if (dws->max_mem_width == DW_MEM_WIDTH_64 && + !((src | dest | len) & 7)) src_width = dst_width = 3; else if (!((src | dest | len) & 3)) src_width = dst_width = 2; @@ -746,7 +748,8 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, mem = sg_dma_address(sg); len = sg_dma_len(sg); - if (!((mem | len) & 7)) + if (dws->max_mem_width == DW_MEM_WIDTH_64 && + !((mem | len) & 7)) mem_width = 3; else if (!((mem | len) & 3)) mem_width = 2; @@ -813,7 +816,8 @@ slave_sg_todev_fill_desc: mem = sg_dma_address(sg); len = sg_dma_len(sg); - if (!((mem | len) & 7)) + if (dws->max_mem_width == DW_MEM_WIDTH_64 && + !((mem | len) & 7)) mem_width = 3; else if (!((mem | len) & 3)) mem_width = 2; diff --git a/include/linux/dw_dmac.h b/include/linux/dw_dmac.h index 2412e02..330afb2 100644 --- a/include/linux/dw_dmac.h +++ b/include/linux/dw_dmac.h @@ -58,6 +58,9 @@ struct dw_dma_slave { u32 cfg_lo; u8 src_master; u8 dst_master; +#define DW_MEM_WIDTH_64 0 +#define DW_MEM_WIDTH_32 1 /* e.g. for avr32 */ + u8 max_mem_width; }; /* Platform-configurable bits in CFG_HI */ -- 1.7.8.0
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