Re: [PATCH 1/3] ata: sata_dwc_460ex: use "dmas" DT property to find dma channel

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Tue, 2015-12-15 at 23:34 +0000, Måns Rullgård wrote:
> Mans Rullgard <mans@mansr.com> writes:
> 
> > Currently this driver only works with a DesignWare DMA engine which
> > it
> > registers manually using the second "reg" address range and
> > interrupt
> > number from the DT node.
> > 
> > This patch makes the driver instead use the "dmas" property if
> > present,
> > otherwise optionally falling back on the old way so existing device
> > trees can continue to work.
> > 
> > With this change, there is no longer any reason to depend on the
> > 460EX
> > machine type so drop that from Kconfig.
> > 
> > Signed-off-by: Mans Rullgard <mans@mansr.com>
> > ---
> >  drivers/ata/Kconfig          |  10 ++-
> >  drivers/ata/sata_dwc_460ex.c | 192 +++++++++++++++++++++++++++--
> > --------------
> >  2 files changed, 131 insertions(+), 71 deletions(-)
> 
> The corresponding patch for the canyonlands devicetree looks
> something
> like this.  I don't have any such hardware or even a manual, so I
> don't
> know what values to use for the various required DT properties of the
> DMA controller node, nor can I test it.  The SATA driver works with a
> different DMA controller on a Sigma Designs chip.
> 
> diff --git a/arch/powerpc/boot/dts/canyonlands.dts
> b/arch/powerpc/boot/dts/canyonlands.dts
> index 3dc75de..959f36e 100644
> --- a/arch/powerpc/boot/dts/canyonlands.dts
> +++ b/arch/powerpc/boot/dts/canyonlands.dts
> @@ -190,12 +190,22 @@
>  					 /* DMA */ 0x2 &UIC0 0xc
> 0x4>;
>  		};
>  
> +		DMA0: dma@bffd0800 {
> +			compatible = "snps,dma-spear1340";
> +			reg = <4 0xbffd0800 0x400>;
> +			interrupt-parent = <&UIC3>;
> +			interrupts = <0x5 0x4>;
> +			#dma-cells = <3>;
> +			/* required properties here */

You have to move the master assignments and other custom dw_dmac
properties. Maybe at some point I will fix that in dw/platform.c.

> +		};
> +
>  		SATA0: sata@bffd1000 {
>  			compatible = "amcc,sata-460ex";
> -			reg = <4 0xbffd1000 0x800 4 0xbffd0800
> 0x400>;
> +			reg = <4 0xbffd1000 0x800>;
>  			interrupt-parent = <&UIC3>;
> -			interrupts = <0x0 0x4       /* SATA */
> -				      0x5 0x4>;     /* AHBDMA */
> +			interrupts = <0x0 0x4>;
> +			dmas = <&DMA0 0 0 1>;
> +			dma-names = "sata-dma";
>  		};
>  
>  		POB0: opb {
> 
> 

-- 
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy