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

[Sudeep Holla]

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@xxxxxxxxxx>
> > >
> > > 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@xxxxxxxxxx>
> > > Signed-off-by: Graeme Gregory <graeme.gregory@xxxxxxxxxx>
> > > Signed-off-by: Tomasz Nowicki <tomasz.nowicki@xxxxxxxxxx>
> > > Signed-off-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
> > > ---
> > >    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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