Subject: [PATCH v3 6/7] ACPI: enable ACPI_DBG2_TABLE on ARM64

From: [email-masked] (Peter Hurley)
Date: Thu, 3 Mar 2016 07:51:49 -0800

On 03/03/2016 03:41 AM, Aleksey Makarov wrote:
> 
> 
> On 03/01/2016 08:25 PM, Peter Hurley wrote:
>> On 03/01/2016 09:02 AM, Aleksey Makarov wrote:
>>>
>>>
>>> On 03/01/2016 05:52 PM, Peter Hurley wrote:
>>>> On 02/29/2016 04:42 AM, Aleksey Makarov wrote:
>>>>> SBBR mentions DBG2 as a mandatory ACPI table.
>>>>> So enable it for ARM64
>>>>
>>>> Why does this have to be opted-in per-arch?
>>>
>>> DBG2 can specify earlycons.  They should start as soon as possible.
>>> On ARM64 it is just after boot tables become available (in arch_init()).
>>> So it has to be per-arch unless we decide not to start earlycons on 
>>> DBG2 ports.
>>
>> OF does all that already but the earlycon opt-in is not per-arch.
> 
> In the last next-XXXX kernel support for OF earlycon depends on
> CONFIG_OF_EARLY_FLATTREE which *is* per-arch.

That's true.

(of_setup_earlycon() was really always CONFIG_OF_EARLY_FLATTREE because
its lone caller was CONFIG_OF_EARLY_FLATTREE).

> Probably we need the same kind of configuration option here,
> something like CONFIG_ACPI_BOOT_TABLES instead of ACPI_DBG2_TABLE.

I'll let acpi maintainers sort that.

>>>>> Signed-off-by: Aleksey Makarov <[email-masked]>
>>>>> ---
>>>>>  arch/arm64/Kconfig       | 1 +
>>>>>  arch/arm64/kernel/acpi.c | 2 ++
>>>>>  2 files changed, 3 insertions(+)
>>>>>
>>>>> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
>>>>> index 9dc5209..0b614d4 100644
>>>>> --- a/arch/arm64/Kconfig
>>>>> +++ b/arch/arm64/Kconfig
>>>>> @@ -3,6 +3,7 @@ config ARM64
>>>>>  	select ACPI_CCA_REQUIRED if ACPI
>>>>>  	select ACPI_GENERIC_GSI if ACPI
>>>>>  	select ACPI_REDUCED_HARDWARE_ONLY if ACPI
>>>>> +	select ACPI_DBG2_TABLE if ACPI
>>>>>  	select ARCH_HAS_DEVMEM_IS_ALLOWED
>>>>>  	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
>>>>>  	select ARCH_HAS_ELF_RANDOMIZE
>>>>> diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
>>>>> index d1ce8e2..3370046 100644
>>>>> --- a/arch/arm64/kernel/acpi.c
>>>>> +++ b/arch/arm64/kernel/acpi.c
>>>>> @@ -208,6 +208,8 @@ void __init acpi_boot_table_init(void)
>>>>>  		pr_err("Failed to init ACPI tables\n");
>>>>>  		if (!param_acpi_force)
>>>>>  			disable_acpi();
>>>>> +	} else {
>>>>> +		acpi_probe_device_table(dbg2);
>>>>>  	}
>>>>>  }
>>>>>  
>>>>>
>>>>
>>
>>
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