Subject: [PATCH v15 07/12] ARM: dts: append hip04 dts

From: [email-masked] (Mark Rutland)
Date: Tue, 29 Jul 2014 18:33:37 +0100

On Tue, Jul 29, 2014 at 06:01:48PM +0100, Olof Johansson wrote:
> On Tue, Jul 29, 2014 at 5:32 AM, Mark Rutland <[email-masked]> wrote:
> > On Tue, Jul 29, 2014 at 03:44:40AM +0100, Haojian Zhuang wrote:
> >> On 29 July 2014 02:06, Mark Rutland <[email-masked]> wrote:
> >> > On Mon, Jul 28, 2014 at 02:57:51PM +0100, Haojian Zhuang wrote:
> >> >> Add hip04-d01.dts & hip04.dtsi for hip04 SoC platform.
> >> >>
> >> >> Signed-off-by: Haojian Zhuang <[email-masked]>
> >> >> ---
> >> >>  arch/arm/boot/dts/Makefile      |   1 +
> >> >>  arch/arm/boot/dts/hip04-d01.dts |  39 ++++++
> >> >>  arch/arm/boot/dts/hip04.dtsi    | 267 ++++++++++++++++++++++++++++++++++++++++
> >> >>  3 files changed, 307 insertions(+)
> >> >>  create mode 100644 arch/arm/boot/dts/hip04-d01.dts
> >> >>  create mode 100644 arch/arm/boot/dts/hip04.dtsi
> >> >>
> >> >> diff --git a/arch/arm/boot/dts/Makefile b/arch/arm/boot/dts/Makefile
> >> >> index 721525e..6587bbf 100644
> >> >> --- a/arch/arm/boot/dts/Makefile
> >> >> +++ b/arch/arm/boot/dts/Makefile
> >> >> @@ -86,6 +86,7 @@ dtb-$(CONFIG_ARCH_HI3xxx) += hi3620-hi4511.dtb
> >> >>  dtb-$(CONFIG_ARCH_HIX5HD2) += hix5hd2-dkb.dtb
> >> >>  dtb-$(CONFIG_ARCH_HIGHBANK) += highbank.dtb \
> >> >>         ecx-2000.dtb
> >> >> +dtb-$(CONFIG_ARCH_HIP04) += hip04-d01.dtb
> >> >>  dtb-$(CONFIG_ARCH_INTEGRATOR) += integratorap.dtb \
> >> >>         integratorcp.dtb
> >> >>  dtb-$(CONFIG_ARCH_KEYSTONE) += k2hk-evm.dtb \
> >> >> diff --git a/arch/arm/boot/dts/hip04-d01.dts b/arch/arm/boot/dts/hip04-d01.dts
> >> >> new file mode 100644
> >> >> index 0000000..661c8e5
> >> >> --- /dev/null
> >> >> +++ b/arch/arm/boot/dts/hip04-d01.dts
> >> >> @@ -0,0 +1,39 @@
> >> >> +/*
> >> >> + *  Copyright (C) 2013-2014 Linaro Ltd.
> >> >> + *  Author: Haojian Zhuang <[email-masked]>
> >> >> + *
> >> >> + *  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
> >> >> + *  publishhed by the Free Software Foundation.
> >> >> + */
> >> >> +
> >> >> +/dts-v1/;
> >> >> +
> >> >> +/* For bootwrapper */
> >> >> +/memreserve/ 0x10c00000 0x00010000;
> >> >
> >> > How exactly is this bootwrapper used? Is the kernel compiled into it?
> >> >
> >> > It might make more sense for the wrapper build system to inject
> >> > bootwrapper-related properties. Then the DTB is less likely to
> >> > amalgamate hacks to workaround differences between versions, and can be
> >> > used on systems without a wrapper without throwing away some memory.
> >> >
> >>
> >> In this platform, we relied on the bootwrapper. If I discard this,
> >> I'll fail to bring up all secondary cores.
> >
> > What loads the boot wrapper into memory, and from where?
> >
> > In another reply you mentioned you're using UEFI. Is this wrapper
> > considered part of your UEFI implementation? If so it should be reserved
> > in the UEFI memory map, and there should be no need of memory nodes or
> > memreserves -- all that should come from UEFI.
> 
> There's no UEFI memory map parsing on 32-bit, is there?

Apparently not, so this can be ignored. Sorry for the noise.

That said I'm slightly confused by the decision to use UEFI given that
we can't use the standard EFI boot mechanism and services on 32-bit.

> > What exactly is the boot wrapper in charge of?
> >
> > What is the split in responsiblity between the wrapper and the kernel?
> 
> Sounds like it's just the trampoline code that's executed at CPU
> spin-up time. I wouldn't be surprised if there's a register somewhere
> on the same controller that you poke the cpu to life that you can
> write what address for it to start executing at, or at least some
> other location where it can be redirected somewhere else. It's very
> unlikely a wired-in address in hardware. Or so I hope. :-)

Me too.

> >> >> +               };
> >> >> +
> >> >> +               fabric: fabric {
> >> >> +                       compatible = "hisilicon,hip04-fabric";
> >> >> +                       reg = <0x302a000 0x1000>;
> >> >
> >> > How is this going to be used?
> >> >
> >>
> >> Fabric could configure snoop filter of multiple cluster. I don't have
> >> the manual. I only know this.
> >
> > Is this accessible to the non-secure side?
> >
> > If the firmware is currently programming things correctly then we
> > shouldn't need this for now.
> 
> with MCPM clusters get powered up and down, it's not uncommon to have
> to take them out of coherence domains.

Sure, but that won't be possible if those registers are secure-only
given the comments that secondaries are demoted to hyp by the wrapper.
That might be possible to work around, but we might be in for further
pain given the primary is already in a non-secure mode.

It might be that this is useful for performance monitoring on the
non-secure side anyway, but without a user it might make more sense to
just drop the node for now.

> >> >> +               };
> >> >> +
> >> >> +               dual_timer0: dual_timer at 3000000 {
> >> >> +                       compatible = "arm,sp804", "arm,primecell";
> >> >> +                       reg = <0x3000000 0x1000>;
> >> >> +                       interrupts = <0 224 4>;
> >> >> +                       clocks = <&clock HIP04_CLK_50M>;
> >> >> +                       clock-names = "apb_pclk";
> >> >> +               };
> >> >
> >> > I thought sp804 had two clocks (one for AMBA and one for the actual
> >> > timer). What's going on here?
> >> >
> >>
> >> If only one clock is configured at here, sp804 driver believes that
> >> clk2 is same as clk1.
> >
> > I'm not keen on relying on that. It's arguably a bug in the driver.
> 
> The driver should warn, but we can't make it fail on it now. :(

Yeah. I should revive my series for that. So far everyone seems to be
happy with just hacking around it :(

Thanks,
Mark.