Re: [PATCH v8 2/3] DMA: Freescale: Add new 8-channel DMA enginedevice tree nodes

From: Mark Rutland
Date: Wed Aug 28 2013 - 08:52:13 EST

On Wed, Aug 28, 2013 at 07:54:01AM +0100, Hongbo Zhang wrote:
> On 08/27/2013 07:35 PM, Mark Rutland wrote:
> > On Tue, Aug 27, 2013 at 11:42:02AM +0100, hongbo.zhang@xxxxxxxxxxxxx wrote:
> >> From: Hongbo Zhang <hongbo.zhang@xxxxxxxxxxxxx>
> >>
> >> Freescale QorIQ T4 and B4 introduce new 8-channel DMA engines, this patch adds
> >> the device tree nodes for them.
> >>
> >> Signed-off-by: Hongbo Zhang <hongbo.zhang@xxxxxxxxxxxxx>
> >> ---
> >> .../devicetree/bindings/powerpc/fsl/dma.txt | 66 ++++++++++++++++
> >> arch/powerpc/boot/dts/fsl/b4si-post.dtsi | 4 +-
> >> arch/powerpc/boot/dts/fsl/elo3-dma-0.dtsi | 81 ++++++++++++++++++++
> >> arch/powerpc/boot/dts/fsl/elo3-dma-1.dtsi | 81 ++++++++++++++++++++
> >> arch/powerpc/boot/dts/fsl/t4240si-post.dtsi | 4 +-
> >> 5 files changed, 232 insertions(+), 4 deletions(-)
> >> create mode 100644 arch/powerpc/boot/dts/fsl/elo3-dma-0.dtsi
> >> create mode 100644 arch/powerpc/boot/dts/fsl/elo3-dma-1.dtsi
> >>
> >> diff --git a/Documentation/devicetree/bindings/powerpc/fsl/dma.txt b/Documentation/devicetree/bindings/powerpc/fsl/dma.txt
> >> index ddf17af..10fd031 100644
> >> --- a/Documentation/devicetree/bindings/powerpc/fsl/dma.txt
> >> +++ b/Documentation/devicetree/bindings/powerpc/fsl/dma.txt
> >> @@ -126,6 +126,72 @@ Example:
> >> };
> >> };
> >>
> >> +** Freescale Elo3 DMA Controller
> >> + This is EloPlus controller with 8 channels, used in Freescale Txxx and Bxxx
> >> + series chips, such as t1040, t4240, b4860.
> >> +
> >> +Required properties:
> >> +
> >> +- compatible : must include "fsl,elo3-dma"
> >> +- reg : <registers specifier for DMA general status reg>
> >> +- ranges : describes the mapping between the address space of the
> >> + DMA channels and the address space of the DMA controller
> >> +
> >> +- DMA channel nodes:
> >> + - compatible : must include "fsl,eloplus-dma-channel"
> >> + - reg : <registers specifier for channel>
> >> + - interrupts : <interrupt specifier for DMA channel IRQ>
> >> + - interrupt-parent : optional, if needed for interrupt mapping
> >> +
> >> +Example:
> >> +dma@100300 {
> >> + #address-cells = <1>;
> >> + #size-cells = <1>;
> >> + compatible = "fsl,elo3-dma";
> >> + reg = <0x100300 0x4 0x100600 0x4>;
> > Is that one reg entry where #size-cells=2 and #address-cells=2?
> >
> > That's what the binding implies (given it only describes a single reg
> > entry).
> >
> > if it's two entries, we should make that explicit (both in the binding
> > and example):
> >
> > reg = <0x100300 0x4>,
> > <0x100600 0x4>;
> Yes they are two entries, I will change it this way.

Ok. Could you make sure you document what the two reg entries correspond
to? That's not clear from "<registers specifier for channel>".

> >> + ranges = <0x0 0x100100 0x500>;
> > If it is one reg entry then the example ranges property isn't big enough
> > to contain the parent-bus-address.
> They are two reg entries, so the range is big enough.

Ok.

> >
> >> + dma-channel@0 {
> >> + compatible = "fsl,eloplus-dma-channel";
> >> + reg = <0x0 0x80>;
> >> + interrupts = <28 2 0 0>;
> >> + };
> >> + dma-channel@80 {
> >> + compatible = "fsl,eloplus-dma-channel";
> >> + reg = <0x80 0x80>;
> >> + interrupts = <29 2 0 0>;
> >> + };
> >> + dma-channel@100 {
> >> + compatible = "fsl,eloplus-dma-channel";
> >> + reg = <0x100 0x80>;
> >> + interrupts = <30 2 0 0>;
> >> + };
> >> + dma-channel@180 {
> >> + compatible = "fsl,eloplus-dma-channel";
> >> + reg = <0x180 0x80>;
> >> + interrupts = <31 2 0 0>;
> >> + };
> >> + dma-channel@300 {
> >> + compatible = "fsl,eloplus-dma-channel";
> >> + reg = <0x300 0x80>;
> >> + interrupts = <76 2 0 0>;
> >> + };
> >> + dma-channel@380 {
> >> + compatible = "fsl,eloplus-dma-channel";
> >> + reg = <0x380 0x80>;
> >> + interrupts = <77 2 0 0>;
> >> + };
> >> + dma-channel@400 {
> >> + compatible = "fsl,eloplus-dma-channel";
> >> + reg = <0x400 0x80>;
> >> + interrupts = <78 2 0 0>;
> >> + };
> >> + dma-channel@480 {
> >> + compatible = "fsl,eloplus-dma-channel";
> >> + reg = <0x480 0x80>;
> >> + interrupts = <79 2 0 0>;
> >> + };
> >> +};
> >> +
> >> Note on DMA channel compatible properties: The compatible property must say
> >> "fsl,elo-dma-channel" or "fsl,eloplus-dma-channel" to be used by the Elo DMA
> >> driver (fsldma). Any DMA channel used by fsldma cannot be used by another
> >> diff --git a/arch/powerpc/boot/dts/fsl/b4si-post.dtsi b/arch/powerpc/boot/dts/fsl/b4si-post.dtsi
> >> index 7399154..ea53ea1 100644
> >> --- a/arch/powerpc/boot/dts/fsl/b4si-post.dtsi
> >> +++ b/arch/powerpc/boot/dts/fsl/b4si-post.dtsi
> >> @@ -223,13 +223,13 @@
> >> reg = <0xe2000 0x1000>;
> >> };
> >>
> >> -/include/ "qoriq-dma-0.dtsi"
> >> +/include/ "elo3-dma-0.dtsi"
> >> dma@100300 {
> >> fsl,iommu-parent = <&pamu0>;
> >> fsl,liodn-reg = <&guts 0x580>; /* DMA1LIODNR */
> >> };
> >>
> >> -/include/ "qoriq-dma-1.dtsi"
> >> +/include/ "elo3-dma-1.dtsi"
> >> dma@101300 {
> >> fsl,iommu-parent = <&pamu0>;
> >> fsl,liodn-reg = <&guts 0x584>; /* DMA2LIODNR */
> >> diff --git a/arch/powerpc/boot/dts/fsl/elo3-dma-0.dtsi b/arch/powerpc/boot/dts/fsl/elo3-dma-0.dtsi
> >> new file mode 100644
> >> index 0000000..69a3277
> >> --- /dev/null
> >> +++ b/arch/powerpc/boot/dts/fsl/elo3-dma-0.dtsi
> >> @@ -0,0 +1,81 @@
> >> +/*
> >> + * QorIQ DMA device tree stub [ controller @ offset 0x100000 ]
> > Copy-pasted?
> >
> > Presumably should be "Elo3 DMA devicetree stub", or similar?
> >
> > Similarly for elo3-dma-1.dtsi.
> Yes copy-pasted, but QorIQ isn't wrong, it is name of Freescale series
> chips.
> To be more specific, I'd like to use "QorIQ Elo3 DMA devicetree stub"

That sounds good to me.

Cheers,
Mark.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/