[IA64] add driver for ACPI methods to call native firmware

This driver for HPQ5001 devices installs a global ACPI OpRegion handler.
AML methods can use this OpRegion to call native firmware entry points.

ACPI does not define a mechanism for AML methods to call native firmware
interfaces such as PAL or SAL.  This OpRegion handler adds such a mechanism.
After the handler is installed, an AML method can call native firmware by
storing the arguments and firmware entry point to specific offsets in the
OpRegion.  When AML reads the "return value" offset from the OpRegion, this
handler loads up the arguments, makes the firmware call, and returns the
result.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 8c39913d172..2e6310b8eab 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -461,6 +461,16 @@ config IA64_ESI
 	  firmware extensions, such as the ability to inject memory-errors
 	  for test-purposes.  If you're unsure, say N.
 
+config IA64_HP_AML_NFW
+	bool "Support ACPI AML calls to native firmware"
+	help
+	  This driver installs a global ACPI Operation Region handler for
+	  region 0xA1.  AML methods can use this OpRegion to call arbitrary
+	  native firmware functions.  The driver installs the OpRegion
+	  handler if there is an HPQ5001 device or if the user supplies
+	  the "force" module parameter, e.g., with the "aml_nfw.force"
+	  kernel command line option.
+
 source "drivers/sn/Kconfig"
 
 config KEXEC