On Mon, 2016-01-25 at 07:32 +0000, Vineet Gupta wrote: > On Monday 25 January 2016 12:55 AM, Mans Rullgard wrote: > > From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> > > > > 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.shevchenko@xxxxxxxxxxxxxxx> > > Signed-off-by: Mans Rullgard <mans@xxxxxxxxx> > > --- > > 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). While this comment is good, I have still note that using non-power of 2 values will not break anything. Least power of two number will be used in that case. So, means I would suggest to replace 'always' by 'better to be' or something like that. > > > ... > > @@ -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 -- Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> Intel Finland Oy -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
