On Monday 25 January 2016 12:55 AM, Mans Rullgard wrote: > From: Andy Shevchenko <andriy.shevche...@linux.intel.com> > > There are several changes are done here: > > - Convert the property to be in bytes > > Much more convenient than keeping encoded value. > > - Use one value for all AHB masters for now > > It seems in practice we have no controllers where masters have different > data bus width, we still might return to distinct values when there is a > use > case. > > - Rename data_width to data-width in the device tree bindings. > > - While here, replace dwc_fast_ffs() by __ffs(). > > Signed-off-by: Andy Shevchenko <andriy.shevche...@linux.intel.com> > Signed-off-by: Mans Rullgard <m...@mansr.com> > --- > This patch changes the DT binding, so it should probably be amended for > compatibility with old device trees. I've included it as is since I think > the change as such is good. > --- > Documentation/devicetree/bindings/dma/snps-dma.txt | 5 ++- > arch/arc/boot/dts/abilis_tb10x.dtsi | 2 +- > arch/arm/boot/dts/spear13xx.dtsi | 4 +-- > drivers/dma/dw/core.c | 40 > +++------------------- > drivers/dma/dw/platform.c | 8 ++--- > drivers/dma/dw/regs.h | 2 +- > include/linux/platform_data/dma-dw.h | 5 ++- > 7 files changed, 16 insertions(+), 50 deletions(-) > > diff --git a/Documentation/devicetree/bindings/dma/snps-dma.txt > b/Documentation/devicetree/bindings/dma/snps-dma.txt > index c99c1ffac199..fe7f7710a6b4 100644 > --- a/Documentation/devicetree/bindings/dma/snps-dma.txt > +++ b/Documentation/devicetree/bindings/dma/snps-dma.txt > @@ -13,8 +13,7 @@ Required properties: > - chan_priority: priority of channels. 0 (default): increase from chan 0->n, > 1: > increase from chan n->0 > - block_size: Maximum block size supported by the controller > -- data_width: Maximum data width supported by hardware per AHB master > - (0 - 8bits, 1 - 16bits, ..., 5 - 256bits) > +- data-width: Maximum data width supported by hardware (in bytes)
To the reader this suggests a value truely byte granular, but code uses ffs implying that it is still power of 2. Can you mention this here (....in bytes, always power of 2). > ... > @@ -726,10 +710,7 @@ dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t > dest, dma_addr_t src, > > dwc->direction = DMA_MEM_TO_MEM; > > - data_width = dw->data_width[dwc->m_master]; > - > - src_width = dst_width = min_t(unsigned int, data_width, > - dwc_fast_ffs(src | dest | len)); > + src_width = dst_width = __ffs(dw->data_width | src | dest | len); > ... -Vineet
