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SubjectRe: [PATCH 01/19] ARM64 / ACPI: Get RSDP and ACPI boot-time tables


On 28/07/14 23:49, Graeme Gregory wrote:
>
> On 28/07/2014 19:29, Sudeep Holla wrote:
>>
>>
>> On 24/07/14 14:00, Hanjun Guo wrote:
>>> From: Al Stone <al.stone@linaro.org>
>>>
>>> As we want to get ACPI tables to parse and then use the information
>>> for system initialization, we should get the RSDP (Root System
>>> Description Pointer) first, it then locates Extended Root Description
>>> Table (XSDT) which contains all the 64-bit physical address that
>>> pointer to other boot-time tables.
>>>
>>> Introduce acpi.c and its related head file in this patch to provide
>>> fundamental needs of extern variables and functions for ACPI core,
>>> and then get boot-time tables as needed.
>>> - asm/cpu.h need for ACPI core and will be updated in the future to
>>> add definitions for arch_(un)register_cpu which are required for
>>> ACPI based physical CPU hotplug;
>>> - asm/acenv.h for arch specific ACPICA environments and
>>> implementation;
>>> - asm/acpi.h for arch specific variables and functions needed by
>>> ACPI driver core;
>>> - acpi.c for ARM64 related ACPI implementation for ACPI driver
>>> core;
>>>
>>> acpi_boot_table_init() is introduced to get RSDP and boot-time tables,
>>> it will be called in setup_arch() before paging_init(), so we should
>>> use eary_memremap() mechanism here to get the RSDP and all the table
>>> pointers.
>>>
>>> Signed-off-by: Al Stone <al.stone@linaro.org>
>>> Signed-off-by: Graeme Gregory <graeme.gregory@linaro.org>
>>> Signed-off-by: Tomasz Nowicki <tomasz.nowicki@linaro.org>
>>> Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
>>> ---
>>> arch/arm64/include/asm/acenv.h | 18 ++++++++++
>>> arch/arm64/include/asm/acpi.h | 41 ++++++++++++++++++++++
>>> arch/arm64/include/asm/cpu.h | 11 ++++++
>>> arch/arm64/kernel/Makefile | 1 +
>>> arch/arm64/kernel/acpi.c | 76
>>> ++++++++++++++++++++++++++++++++++++++++
>>> arch/arm64/kernel/setup.c | 4 +++
>>> 6 files changed, 151 insertions(+)
>>> create mode 100644 arch/arm64/include/asm/acenv.h
>>> create mode 100644 arch/arm64/include/asm/acpi.h
>>> create mode 100644 arch/arm64/include/asm/cpu.h
>>> create mode 100644 arch/arm64/kernel/acpi.c
>>>

[...]

>>> +
>>> +/*
>>> + * MADT must provide at least one GICC structure
>>> + * for GIC initialization, so CPU will be
>>> + * always available in MADT on ARM64
>>> + */
>>> +static inline bool acpi_has_cpu_in_madt(void)
>>> +{
>>> + return 1;
>>> +}
>>> +
>>
>> I don't see the user of this function in the series, it's better to
>> remove. Moreover the comment is so misleading. We will have CPU UID
>> not the CPU itself in MADT.
>>
> This is actually required for a patch that is now upstreamed. Comment
> should actually say that its checking for the posibility that the CPU
> can be initialised from the MADT. Its used from core in crash kernel
> case where boot CPU is not necessarily CPU0 like spec demands.
>

Ah OK, I now see that in Rafael's linux-pm/linux-next. Sorry I might have
missed to notice that and I assumed this series is based on mainline.

Regards,
Sudeep



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