[PATCH v4 07/13] ARM: shmobile: apmu: Add APMU DT support via Enable method

[Sergei Shtylyov]

Hello.

On 06/24/2016 10:44 AM, Geert Uytterhoeven wrote:

>>> From: Magnus Damm <damm+renesas at opensource.se>
>>> Allow DT configuration of the APMU hardware in the case when the APMU is
>>> pointed out in the DTB via the enable-method. The ability to configure
>>> the APMU via C code is still kept intact to prevent DTB breakage for older
>>> SoCs that do not rely on the enable-method for SMP support.
>>>
>>> Signed-off-by: Magnus Damm <damm+renesas at opensource.se>
>>> [geert: Fix CONFIG_SMP=n build]
>>> Signed-off-by: Geert Uytterhoeven <geert+renesas at glider.be>
>>
>> [...]
>>
>>> diff --git a/arch/arm/mach-shmobile/platsmp-apmu.c
>>> b/arch/arm/mach-shmobile/platsmp-apmu.c
>>> index c1558ef0c590dd3e..0c6bb458b7a45128 100644
>>> --- a/arch/arm/mach-shmobile/platsmp-apmu.c
>>> +++ b/arch/arm/mach-shmobile/platsmp-apmu.c
>>
>> [...]
>>>
>>> +static int shmobile_smp_apmu_boot_secondary_md21(unsigned int cpu,
>>> +                                                struct task_struct *idle)
>>> +{
>>> +       /* Error out when hardware debug mode is enabled */
>>> +       if (rcar_gen2_read_mode_pins() & BIT(21)) {
>>> +               pr_warn("Unable to boot CPU%u when MD21 is set\n", cpu);
>>> +               return -ENOTSUPP;
>>> +       }
>>> +
>>> +       return shmobile_smp_apmu_boot_secondary(cpu, idle);
>>> +}
>>> +
>>> +static struct smp_operations apmu_smp_ops __initdata = {
>>> +       .smp_prepare_cpus       = shmobile_smp_apmu_prepare_cpus_dt,
>>> +       .smp_boot_secondary     = shmobile_smp_apmu_boot_secondary_md21,
>>> +#ifdef CONFIG_HOTPLUG_CPU
>>> +       .cpu_can_disable        = shmobile_smp_cpu_can_disable,
>>> +       .cpu_die                = shmobile_smp_apmu_cpu_die,
>>> +       .cpu_kill               = shmobile_smp_apmu_cpu_kill,
>>>  #endif
>>
>>
>>    For the record: it turned out that I tested my non-DT SMP on
>> R8A7792/Blanche with MD21 bit set. And I've just made sure it still works
>> with this implementation (by commenting out the check above.
>>    Also, I was going to try the workaround for MD21 I saw in the BSP tree --

> Which workaround? I only saw the BSP removed the check, but it didn't mention
> why (because E2 and V2H don't need it, or...?).

    I'm looking at the <soc>_smp_prepare_cpus() in 
arch/arm/mach-shmobile/setup-<soc>.c in the 
'bsp/v3.10.31-ltsi/rcar-gen2-1.9.6' branch of Simon's renesas-backport.git. 
The all have the code to handle MD21 bit set (by setting some bits in 
CA{7,15}DBGRCR.

>> perhaps it'll help get R8A7791 working w/MD21 set...
>
> Does your Porter work with the other MD21 setting (and the check commented
> out, of coutse)?

    Yes, I've made sure it works now.

> Gr{oetje,eeting}s,
>
>                         Geert

MBR, Sergei