Re: [Xen-devel] [PATCH RFC 05/35] ARM64 / ACPI: Parse FADT table to get PSCI flags

[Hanjun Guo <hanjun.guo@xxxxxxxxxx>]

On 2015å02æ05æ 01:45, Stefano Stabellini wrote:
> On Wed, 4 Feb 2015, parth.dixit@xxxxxxxxxx wrote:
> > From: Naresh Bhat <naresh.bhat@xxxxxxxxxx>
> >
> > There are two flags: PSCI_COMPLIANT and PSCI_USE_HVC. When set,
> > the former signals to the OS that the hardware is PSCI compliant.
> > The latter selects the appropriate conduit for PSCI calls by
> > toggling between Hypervisor Calls (HVC) and Secure Monitor Calls
> > (SMC).
> >
> > FADT table contains such information, parse FADT to get the flags
> > for furture usage. At the same time, only ACPI 5.1 or higher verison
> > supports PSCI, and FADT Major.Minor version was introduced in ACPI
> > 5.1, so we will check the version and only parse FADT table with
> > version >= 5.1.
> >
> > If firmware provides ACPI tables with ACPI version less than 5.1,
> > OS will be messed up with those information, so disable ACPI if we
> > get an FADT table with version less that 5.1.
> >
> > Signed-off-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
> > Signed-off-by: Naresh Bhat <naresh.bhat@xxxxxxxxxx>
> > ---
> >   xen/arch/arm/arm64/acpi/arm-core.c | 54 +++++++++++++++++++++++++++++++++++---
> >   xen/arch/arm/setup.c               |  1 +
> >   xen/include/asm-arm/acpi.h         |  2 ++
> >   3 files changed, 54 insertions(+), 3 deletions(-)
> >
> > diff --git a/xen/arch/arm/arm64/acpi/arm-core.c 
> > b/xen/arch/arm/arm64/acpi/arm-core.c
> > index 50a83d6..2b7e2ef 100644
> > --- a/xen/arch/arm/arm64/acpi/arm-core.c
> > +++ b/xen/arch/arm/arm64/acpi/arm-core.c
> > @@ -25,6 +25,7 @@
> >   #if defined(CONFIG_ARM_64) && defined(CONFIG_ACPI)
> >   #include <xen/init.h>
> >   #include <xen/acpi.h>
> > +#include <xen/errno.h>
> >
> >   #include <asm/acpi.h>
> >
> > @@ -42,6 +43,12 @@ EXPORT_SYMBOL(acpi_disabled);
> >   int acpi_pci_disabled;         /* skip ACPI PCI scan and IRQ initialization */
> >   EXPORT_SYMBOL(acpi_pci_disabled);
> >
> > +/* 1 to indicate PSCI is implemented */
> > +int acpi_psci_present;
> > +
> > +/* 1 to indicate HVC must be used instead of SMC as the PSCI conduit */
> > +int acpi_psci_use_hvc;
> Can they be static?
> Also it might be better to define an enum with values: PSCI_ABSENT, PSCI_HVC, 
> PSCI_SMC.
This patch was changed a lot in the latest v8 patch set, I introduced
two static inline function in the head file to replace those two
variables.

Thanks
Hanjun

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