From: Hein Tibosch <hein_tibo...@yahoo.es> v4: now based and tested on 3.6-rc4
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_tibo...@yahoo.es> Acked-by: Viresh Kumar <viresh.ku...@linaro.org> --- drivers/dma/dw_dmac.c | 13 +++++++------ include/linux/dw_dmac.h | 3 +++ 2 files changed, 10 insertions(+), 6 deletions(-) diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c index d3c5a5a..311953c 100644 --- a/drivers/dma/dw_dmac.c +++ b/drivers/dma/dw_dmac.c @@ -190,14 +190,14 @@ static void dwc_initialize(struct dw_dma_chan *dwc) } /*----------------------------------------------------------------------*/ - -static inline unsigned int dwc_fast_fls(unsigned long long v) +static inline unsigned int dwc_fast_fls(unsigned long long v, + struct dw_dma_slave *dws) { /* * We can be a lot more clever here, but this should take care * of the most common optimization. */ - if (!(v & 7)) + if (dws->max_mem_width == DW_MEM_WIDTH_64 && !(v & 7)) return 3; else if (!(v & 3)) return 2; @@ -636,6 +636,7 @@ 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; @@ -655,7 +656,7 @@ dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src, return NULL; } - src_width = dst_width = dwc_fast_fls(src | dest | len); + src_width = dst_width = dwc_fast_fls(src | dest | len, dws); ctllo = DWC_DEFAULT_CTLLO(chan) | DWC_CTLL_DST_WIDTH(dst_width) @@ -755,7 +756,7 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, mem = sg_dma_address(sg); len = sg_dma_len(sg); - mem_width = dwc_fast_fls(mem | len); + mem_width = dwc_fast_fls(mem | len, dws); slave_sg_todev_fill_desc: desc = dwc_desc_get(dwc); @@ -815,7 +816,7 @@ slave_sg_todev_fill_desc: mem = sg_dma_address(sg); len = sg_dma_len(sg); - mem_width = dwc_fast_fls(mem | len); + mem_width = dwc_fast_fls(mem | len, dws); slave_sg_fromdev_fill_desc: desc = dwc_desc_get(dwc); 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
