[PATCH 1/3] arm64: dts: add initial dts for Samsung GH7 SoC and SSDK-GH7 board

[mark.rutland@arm.com (Mark Rutland)]

On Tue, Feb 11, 2014 at 03:16:26AM +0000, Kukjin Kim wrote:
> On 02/12/14 03:15, Mark Rutland wrote:
> > On Tue, Feb 11, 2014 at 06:29:41AM +0000, Kukjin Kim wrote:
> >> Signed-off-by: Kukjin Kim<kgene.kim@samsung.com>
> >> Reviewed-by: Thomas Abraham<thomas.ab@samsung.com>
> >> Cc: Catalin Marinas<catalin.marinas@arm.com>
> >> ---
> >>   arch/arm64/boot/dts/samsung-gh7.dtsi     |  108 ++++++++++++++++++++++++++++++
> >>   arch/arm64/boot/dts/samsung-ssdk-gh7.dts |   26 +++++++
> >>   2 files changed, 134 insertions(+)
> >>   create mode 100644 arch/arm64/boot/dts/samsung-gh7.dtsi
> >>   create mode 100644 arch/arm64/boot/dts/samsung-ssdk-gh7.dts
> >>
> >> diff --git a/arch/arm64/boot/dts/samsung-gh7.dtsi b/arch/arm64/boot/dts/samsung-gh7.dtsi
> >> new file mode 100644
> >> index 0000000..5b8785c
> >> --- /dev/null
> >> +++ b/arch/arm64/boot/dts/samsung-gh7.dtsi
> >> @@ -0,0 +1,108 @@
> >> +/*
> >> + * SAMSUNG GH7 SoC device tree source
> >> + *
> >> + * Copyright (c) 2014 Samsung Electronics Co., Ltd.
> >> + *		http://www.samsung.com
> >> + *
> >> + * This program is free software; you can redistribute it and/or modify
> >> + * it under the terms of the GNU General Public License version 2 as
> >> + * published by the Free Software Foundation.
> >> +*/
> >> +
> >> +/dts-v1/;
> >> +
> >> +/memreserve/ 0x80000000 0x0C400000;
> >
> > That looks _very_ large. What is this for?
> >
> Yes, I know but we need to reserve that for EL3 monitor, UEFI services, 
> secure, hypervisor and scan chanin...

OK. How much of that memory does the kernel need to know about then?

Surely the kernel shouldn't be able to map the EL3 monitor or hypervisor
at all?

What address is the kernel getting loaded at if everything up to
0x8C400000 isn't usable?

[...]

> 
> > [...]
> >
> >> +	amba {
> >> +		compatible = "arm,amba-bus";
> >> +		#address-cells =<1>;
> >> +		#size-cells =<1>;
> >> +		ranges;
> >> +
> >> +		serial at 12c00000 {
> >> +			compatible = "arm,pl011", "arm,primecell";
> >> +			reg =<0x12c00000 0x10000>;
> >> +			interrupts =<418>;
> >> +		};
> >> +
> >> +		serial at 12c20000 {
> >> +			compatible = "arm,pl011", "arm,primecell";
> >> +			reg =<0x12c20000 0x10000>;
> >> +			interrupts =<420>;
> >> +		};
> >
> > Don't these need clocks?
> >
> We don't need and the clocks will be handled by bootloader...

While that might be sufficient for the device to function, Linux doesn't
know that from this DT, and as far as I can see the device can't
possibly probe, as no clocks are provided through platform data:

of_platform_bus_create will call of_amba_device_create for anyting
compatible with "arm,primecell". This in turn will call amba_device_add,
which will call amba_get_enable_pclk. Then clk_get(&pcdev->dev,
"apb_pclk") should fail, amba_device_add should fail, and
of_platform_bus_create will stop trying to probe the node.
of_platform_populate will carry on probing other nodes.

Surely the pl011 nodes at least need "apb_pclk"?

Cheers,
Mark.