Re: [PATCH v3 05/12] dt-bindings: soc: Add Aspeed XDMA Engine

Andrew Jeffery
2019-12-19T21:12:26Z

On Fri, 20 Dec 2019, at 02:18, Eddie James wrote:
>
> On 12/18/19 5:12 PM, Andrew Jeffery wrote:
> >
> > On Thu, 19 Dec 2019, at 01:39, Eddie James wrote:
> >> Document the bindings for the Aspeed AST25XX and AST26XX XDMA engine.
> >>
> >> Signed-off-by: Eddie James <eajames@linux.ibm.com>
> >> Reviewed-by: Rob Herring <robh@kernel.org>
> >> ---
> >> Changes since v2:
> >> - Remove 'sdmc', rename 'vga-mem' to 'memory'
> >>
> >> .../devicetree/bindings/soc/aspeed/xdma.txt | 40 +++++++++++++++++++
> >> MAINTAINERS | 6 +++
> >> 2 files changed, 46 insertions(+)
> >> create mode 100644 Documentation/devicetree/bindings/soc/aspeed/xdma.txt
> >>
> >> diff --git a/Documentation/devicetree/bindings/soc/aspeed/xdma.txt
> >> b/Documentation/devicetree/bindings/soc/aspeed/xdma.txt
> >> new file mode 100644
> >> index 000000000000..58253ea1587b
> >> --- /dev/null
> >> +++ b/Documentation/devicetree/bindings/soc/aspeed/xdma.txt
> >> @@ -0,0 +1,40 @@
> >> +Aspeed AST25XX and AST26XX XDMA Engine
> >> +
> >> +The XDMA Engine embedded in the AST2500 and AST2600 SOCs can perform
> >> automatic
> >> +DMA operations over PCI between the SOC (acting as a BMC) and a host
> >> processor.
> >> +
> >> +Required properties:
> >> + - compatible : must be "aspeed,ast2500-xdma" or
> >> + "aspeed,ast2600-xdma"
> >> + - reg : contains the address and size of the memory region
> >> + associated with the XDMA engine registers
> >> + - clocks : clock specifier for the clock associated with the
> >> + XDMA engine
> >> + - resets : reset specifier for the syscon reset associated with
> >> + the XDMA engine
> >> + - interrupts-extended : two interrupt cells; the first specifies the
> >> global
> >> + interrupt for the XDMA engine and the second
> >> + specifies the PCI-E reset or PERST interrupt.
> >> + - scu : a phandle to the syscon node for the system control
> >> + unit of the SOC
> > I think this should be aspeed,scu.
>
>
> Sure.
>
>
> >
> >> + - memory : contains the address and size of the memory area to
> >> + be used by the XDMA engine for DMA operations
> > Hmm, I was thinking more like a phandle to a reserved memory region,
> > like we have in the aspeed-lpc-ctrl binding.
>
>
> I think I mentioned before, but that doesn't work with the VGA memory.
> Linux can't reserve it. I haven't quite understood what happens in the
> memory system but I've tried it and it didn't work.
>

Yeah, I think you have mentioned that before, sorry for the noise.

Andrew