Re: [EXT] [PATCH 2/2] arm64: dts: ls1028a: add "fsl,vf610-edma" compatible

[Michael Walle]

Hi Peng,

Am 2020-03-07 03:09, schrieb Peng Ma:
> > -----Original Message-----
> > From: Michael Walle <michael@xxxxxxxx>
> > Sent: 2020å3æ7æ 4:54
> > To: dmaengine@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx;
> > linux-kernel@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> > Cc: Vinod Koul <vkoul@xxxxxxxxxx>; Rob Herring <robh+dt@xxxxxxxxxx>; 
> > Mark
> > Rutland <mark.rutland@xxxxxxx>; Shawn Guo <shawnguo@xxxxxxxxxx>; Leo 
> > Li
> > <leoyang.li@xxxxxxx>; Peng Ma <peng.ma@xxxxxxx>; Michael Walle
> > <michael@xxxxxxxx>
> > Subject: [EXT] [PATCH 2/2] arm64: dts: ls1028a: add "fsl,vf610-edma"
> > compatible
> >
> > Caution: EXT Email
> >
> > The bootloader does the IOMMU fixup and dynamically adds the "iommus"
> > property to devices according to its compatible string. In case of the 
> > eDMA
> > controller this property is missing. Add it. After that the IOMMU will 
> > work with
> > the eDMA core.
> >
> > Signed-off-by: Michael Walle <michael@xxxxxxxx>
> > ---
> > arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi
> > b/arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi
> > index b152fa90cf5c..aa467bff2209 100644
> > --- a/arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi
> > +++ b/arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi
> > @@ -447,7 +447,7 @@
> >
> >                edma0: dma-controller@22c0000 {
> >                        #dma-cells = <2>;
> > -                       compatible = "fsl,ls1028a-edma";
> > +                       compatible = "fsl,ls1028a-edma",
> > + "fsl,vf610-edma";
> Hi Michael,
>
> You should change it on bootloader instead of kernel, Some Reg of
> LS1028a is different
> from others, So we used compatible "fsl,ls1028a-edm" to distinguish "
> fsl,vf610-edma".

Yes this might be the right thing to do. So since it is NXPs bootloader
feel free to fix that ;) Looking at the u-boot code right now, I don't
even know it that is the right fix at all. The fixup code in u-boot is
SoC independent (its in fsl_icid.h and is enabled with CONFIG_LSCH3, ie
your chassis version). For example, the sdhc fixup will scan the nodes
for "compatible = fsl,esdhc", which is also the secondary compatible
for the "ls1028a-esdhc" compatible.

And here is another reason to have it this way: we need backwards
compatibility, the are already boards out there whose bootloader will
fix-up the "old" node. Thus I don't see any other possibilty.

-michael

> Thanks,
> Peng
> >                        reg = <0x0 0x22c0000 0x0 0x10000>,
> >                              <0x0 0x22d0000 0x0 0x10000>,
> >                              <0x0 0x22e0000 0x0 0x10000>;
> > --
> > 2.20.1