Changes to acpi_gpiobus.c handle discovering and parsing the _AEI
objects and storing necessary data in device ivars. A new gpioaei.c
file implements the device, which simply requests an interrupt when
the pin is triggered and invokes the appropriate _Exx or _Lxx ACPI
method.
This makes the GPIO "power button" work on arm64 Graviton systems,
allowing EC2 "Stop"/"Reboot" instance calls to be handled cleanly.
(Prior to this change, those requests would time out after 4 minutes
and the instance would be forcibly killed.)
Reviwed by: imp, andrew, Ahmad Khalifa
MFC after: 3 days
Sponsored by: Amazon
Differential Revision: https://reviews.freebsd.org/D47253
Co-authored-by: Andrew Turner <andrew@FreeBSD.org>
(cherry picked from commit 9709bda03cd0f20eba0ba4276fc3c2e06354a54f)
includes the FDT option. Use OPT_FDT to conditionally compile modules
that require FDT support.
In the past we've gotten away with using the arch name as a proxy for FDT
support in makefile conditional logic, but now mips has some platforms with
fdt support and some without and we need a more direct test.
This is primarily done to save a few bytes here and there on embedded
systems with limited flash space for kernels - a very limited (sub-1MB)
space may be available for the kernel and may only support gzip encoding.
The rootfs can be LZMA compressed.
