ACPI, x86/boot: Introduce the ->reduced_hw_early_init() ACPI callback

Some ACPI hardware reduced platforms need to initialize certain devices
defined by the ACPI hardware specification even though in principle
those devices should not be present in an ACPI hardware reduced platform.

To allow that to happen, make it possible to override the generic
x86_init callbacks and provide a custom legacy_pic value, add a new
->reduced_hw_early_init() callback to struct x86_init_acpi and make
acpi_reduced_hw_init() use it.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-acpi@vger.kernel.org
Link: http://lkml.kernel.org/r/20180220180506.65523-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h
index 2e2c34d2bb00..5bd45a8f5ae3 100644
--- a/arch/x86/include/asm/x86_init.h
+++ b/arch/x86/include/asm/x86_init.h
@@ -133,9 +133,11 @@ struct x86_hyper_init {
 /**
  * struct x86_init_acpi - x86 ACPI init functions
  * @get_root_pointer:		get RSDP address
+ * @reduced_hw_early_init:	hardware reduced platform early init
  */
 struct x86_init_acpi {
 	u64 (*get_root_pointer)(void);
+	void (*reduced_hw_early_init)(void);
 };
 
 /**