[PATCH v4 02/10] ARM: dts: list the CPU nodes for Exynos5250

[Chander Kashyap]

Hi Viresh,

On 29 August 2013 17:21, Tomasz Figa <t.figa at samsung.com> wrote:
> Hi Viresh,
>
> On Thursday 29 of August 2013 13:45:56 Viresh Kumar wrote:
>> On Tue, Jun 18, 2013 at 11:59 AM, Chander Kashyap
>>
>> <chander.kashyap at linaro.org> wrote:
>> > Instead of having to specify the number for CPUs in Exynos5250 in
>> > platsmp.c file, let the number of CPUs be determined by having this
>> > information listed in Exynos5250 device tree file.
>> >
>> > Signed-off-by: Chander Kashyap <chander.kashyap at linaro.org>
>> > Reviewed-by: Tomasz Figa <t.figa at samsung.com>
>> > ---
>> >
>> >  arch/arm/boot/dts/exynos5250.dtsi |   16 ++++++++++++++++
>> >  arch/arm/mach-exynos/platsmp.c    |   10 +++++++---
>> >  2 files changed, 23 insertions(+), 3 deletions(-)
>> >
>> > diff --git a/arch/arm/boot/dts/exynos5250.dtsi
>> > b/arch/arm/boot/dts/exynos5250.dtsi index 63ca03d..1aeef98 100644
>> > --- a/arch/arm/boot/dts/exynos5250.dtsi
>> > +++ b/arch/arm/boot/dts/exynos5250.dtsi
>> > @@ -50,6 +50,22 @@
>> >
>> >                 pinctrl3 = &pinctrl_3;
>> >
>> >         };
>> >
>> > +       cpus {
>> > +               #address-cells = <1>;
>> > +               #size-cells = <0>;
>> > +
>> > +               cpu at 0 {
>> > +                       device_type = "cpu";
>> > +                       compatible = "arm,cortex-a15";
>> > +                       reg = <0>;
>> > +               };
>> > +               cpu at 1 {
>> > +                       device_type = "cpu";
>> > +                       compatible = "arm,cortex-a15";
>> > +                       reg = <1>;
>> > +               };
>> > +       };
>> > +
>> >
>> >         pd_gsc: gsc-power-domain at 0x10044000 {
>> >
>> >                 compatible = "samsung,exynos4210-pd";
>> >                 reg = <0x10044000 0x20>;
>> >
>> > diff --git a/arch/arm/mach-exynos/platsmp.c
>> > b/arch/arm/mach-exynos/platsmp.c index 1a4e4e5..85ea4ca 100644
>> > --- a/arch/arm/mach-exynos/platsmp.c
>> > +++ b/arch/arm/mach-exynos/platsmp.c
>> > @@ -180,10 +180,14 @@ static void __init exynos_smp_init_cpus(void)
>> >
>> >         void __iomem *scu_base = scu_base_addr();
>> >         unsigned int i, ncores;
>> >
>> > -       if (soc_is_exynos5250())
>> > -               ncores = 2;
>> > -       else
>> > +       if (read_cpuid_part_number() == ARM_CPU_PART_CORTEX_A9)
>> >
>> >                 ncores = scu_base ? scu_get_core_count(scu_base) : 1;
>> >
>> > +       else
>> > +               /*
>> > +                * CPU Nodes are passed thru DT and set_cpu_possible
>> > +                * is set by "arm_dt_init_cpu_maps".
>> > +                */
>> > +               return;
>> >
>> >         /* sanity check */
>> >         if (ncores > nr_cpu_ids) {
>>
>> After this patch only one cpu is coming up for me on my Arndale board..
>> Revert of this one fixes the issue though (Tested over v3.11-rc7)
>
I tested on 3.11-rc7.
Both the cpu's are booting. I didnet see any issue.

> It is quite likely that 0 and 1 are not real MPIDR values for CPU cores on
> Exynos5250, because cluster ID might not be 0, as one could expect.
>
@Tomasz:
Mpidr values are correct.

> This is what I found out on Exynos4210 and 4x12, when trying to add CPU
> nodes in DT for them, leading in turn to a series of regressions, for which
> it was to late to do all the necessary code rework to fix them for 3.12, so
> I had to defer this work for next release.

Exynos4210 and 4x12 mpidr values have issue. They do start from
cluster ID 9, which breaks the gic init code.
But that is not the case with exynos 5250.

>
> Best regards,
> Tomasz
>



-- 
with warm regards,
Chander Kashyap