From: heiko@sntech•de (Heiko Stübner)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 2/4] ARM: rockchip: add sram dt nodes and documentation
Date: Tue, 18 Jun 2013 03:17:42 +0200 [thread overview]
Message-ID: <201306180317.42820.heiko@sntech.de> (raw)
In-Reply-To: <51BF9EA7.3030408@gmail.com>
Am Dienstag, 18. Juni 2013, 01:41:27 schrieb Rob Herring:
> On 06/17/2013 05:44 PM, Heiko St?bner wrote:
> > The Rockchip SoCs need a special part of their sram for bringup
> > of additional cores. Therefore the mapped area should be split
> > into a special area for the smp code and a generic area that gets
> > handled by mmio-sram.
> >
> > Signed-off-by: Heiko Stuebner <heiko@sntech•de>
> > ---
> >
> > .../devicetree/bindings/arm/rockchip/smp-sram.txt | 29
> > ++++++++++++++++++++ arch/arm/boot/dts/rk3066a.dtsi
> > | 14 ++++++++++ 2 files changed, 43 insertions(+)
> > create mode 100644
> > Documentation/devicetree/bindings/arm/rockchip/smp-sram.txt
> >
> > diff --git a/Documentation/devicetree/bindings/arm/rockchip/smp-sram.txt
> > b/Documentation/devicetree/bindings/arm/rockchip/smp-sram.txt new file
> > mode 100644
> > index 0000000..9c81fac
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/arm/rockchip/smp-sram.txt
> > @@ -0,0 +1,29 @@
> > +Rockchip SRAM for smp bringup:
> > +------------------------------
> > +
> > +Rockchip smp-capable SoCs use the first part of the sram for the bringup
> > +of the cores. Once the core gets powered up it executes the code that is
> > +residing at the very beginning of the sram.
> > +
> > +While the suspend also needs to have code in the sram that can be
> > realized +with the generic mmio-sram driver and only the smp specific
> > part needs to +be mapped specially in the smp code.
> > +
> > +Therefore split the sram mapping in a smp-specific part that gets used
> > +by the smp code exclusively and a bigger generic part for mmio-sram
> > +
> > +Required node properties:
> > +- compatible value : = "rockchip,rk3066-smp-sram";
> > +- reg : physical base address and the size of the registers window
> > +
> > +Example:
> > +
> > + sram at 10080000 {
> > + compatible = "rockchip,rk3066-smp-sram";
> > + reg = <0x10080000 0x100>;
> > + };
> > +
> > + sram: sram at 10080100 {
> > + compatible = "mmio-sram";
> > + reg = <0x10080100 0x9900>;
>
> I think a better way would be to specify some portion of the sram as
> reserved rather than defining the s/w use of the sram in DT.
> Something like this:
>
> mmio-sram-reserved = <base size base size>;
>
> where base values are relative to reg property base.
hmm, but I don't see how to get then access to the reserved part. As can be
seen in patch 4 [which I've forgotton to cc you in, sorry] the smp-trampoline
gets copied into this area for the core to execute after poweron, so I need to
get the mapped representation of the reserved area.
Or do you mean
- let mmio-sram only allocate the non-reserved spaces for itself
- grab mmio-sram node in the smp code and map the necessary reserved space
This might actually work.
Thanks
Heiko
> > + };
> > diff --git a/arch/arm/boot/dts/rk3066a.dtsi
> > b/arch/arm/boot/dts/rk3066a.dtsi index 26c4311..44eabd2 100644
> > --- a/arch/arm/boot/dts/rk3066a.dtsi
> > +++ b/arch/arm/boot/dts/rk3066a.dtsi
> > @@ -53,6 +53,20 @@
> >
> > reg = <0x1013c000 0x100>;
> >
> > };
> >
> > + /*
> > + * the first part of the sram is needed for the smp
> > + * trampoline code during cpu bringup
> > + */
> > + sram at 10080000 {
> > + compatible = "rockchip,rk3066-smp-sram";
> > + reg = <0x10080000 0x100>;
> > + };
> > +
> > + sram: sram at 10080100 {
> > + compatible = "mmio-sram";
> > + reg = <0x10080100 0x9900>;
> > + };
> > +
> >
> > gic: interrupt-controller at 1013d000 {
> >
> > compatible = "arm,cortex-a9-gic";
> > interrupt-controller;
next prev parent reply other threads:[~2013-06-18 1:17 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-17 22:43 [PATCH 0/4] ARM: rockchip: add smp functionality Heiko Stübner
2013-06-17 22:43 ` [PATCH 1/4] ARM: rockchip: add snoop-control-unit Heiko Stübner
2013-06-17 22:44 ` [PATCH 2/4] ARM: rockchip: add sram dt nodes and documentation Heiko Stübner
2013-06-17 23:41 ` Rob Herring
2013-06-18 1:17 ` Heiko Stübner [this message]
2013-06-18 2:30 ` Rob Herring
2013-06-18 9:35 ` Heiko Stübner
2013-06-17 22:44 ` [PATCH 3/4] ARM: rockchip: add power-management-unit dt node Heiko Stübner
2013-06-17 22:45 ` [PATCH 4/4] ARM: rockchip: add smp bringup code Heiko Stübner
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