[Qemu-devel] [PATCH v2 0/8] Add system_powerdown support on ARM for ACPI and DT

[Shannon Zhao]

ACPI SPEC 5.0 defines GPIO-signaled ACPI Events for Hardware-reduced
platforms(like ARM). It uses GPIO pin to trigger an event to the guest.
For QEMU, here we add PL061 GPIO controller and use PIN 3 for
system_powerdown, reserving PIN 0, 1, 2 for PCI hotplug, CPU hotplug and
memory hotplug.

This patchset adds system_powerdown support on ARM through both ACPI and
DT ways. It adds a GPIO controller(here is PL061) in machine virt and
uses GPIO-singled event for ACPI while gpio-keys for DT. It can be
fetched from [1] and has been tested for the guests starting by ACPI or
DT while guests use systemd or acpid.

a) ACPI way. Since Graeme send a patchset to make ACPI on ARM64 support
amba device[2], it could use PL061 directly without modification to its
kernel driver code. In addition, we should use ACPI to start VM,
referring to below script. QEMU_EFI.fd can be fetched from [3]. 

    qemu-system-aarch64 \
    -smp 1 -m 1024 -M virt \
    -cpu cortex-a57 -nographic \
    -monitor telnet::4444,server,nowait \
    -bios QEMU_EFI.fd \
    -kernel Image \
    -initrd guestfs.cpio.gz \
    -append "rdinit=/sbin/init console=ttyAMA0 mem=512M root=/dev/ram 
earlycon=pl011,0x9000000 rw acpi=force"

b) DT way. Start vm as usual.

    qemu-system-aarch64 \
    -smp 1 -m 1024 -M virt \
    -cpu cortex-a57 -nographic \
    -monitor telnet::4444,server,nowait \
    -kernel Image \
    -initrd guestfs.cpio.gz \
    -append "rdinit=/sbin/init console=ttyAMA0 mem=512M root=/dev/ram 
earlycon=pl011,0x9000000 rw"

Guest internal setup:
If your guest FS uses systemd, you should check file
/lib/udev/rules.d/70-power-switch.rules and add the following line in it
if it doesn't exist.

SUBSYSTEM=="input", KERNEL=="event*", SUBSYSTEMS=="platform",
ATTRS{keys}=="116", TAG+="power-switch"

If your guest FS uses acpid, you should check it has
/etc/acpi/powerbtn.sh and /etc/acpi/events/powerbtn. Refer to [4] for
the setup of acpid.

Thanks,
Shannon

[1] 
https://git.linaro.org/people/shannon.zhao/qemu.git/shortlog/refs/heads/PowerButton_v2
[2] https://lkml.org/lkml/2015/9/30/392
[3] http://people.linaro.org/~shannon.zhao/ACPI_ARM/QEMU_EFI.fd
[4] https://wiki.linaro.org/LEG/Engineering/Kernel/ACPI/GPIOPowerButton

Changes since v1:
* rewrite GPIO Connection Descriptor (Michael)

Shannon Zhao (8):
  hw/arm/virt: Add a GPIO controller
  hw/arm/virt-acpi-build: Add GPIO controller in ACPI DSDT table
  hw/arm/virt-acpi-build: Add power button device in ACPI DSDT table
  hw/acpi/aml-build: Add GPIO Connection Descriptor
  hw/acpi/aml-build: Add a wrapper for GPIO Interrupt Connection
  hw/arm/virt-acpi-build: Add _E03 for Power Button
  hw/arm/virt: Add QEMU powerdown notifier and hook it to GPIO Pin 3
  hw/arm/virt: Add gpio-keys node for Poweroff using DT

 hw/acpi/aml-build.c         | 79 +++++++++++++++++++++++++++++++++++++++++++++
 hw/arm/virt-acpi-build.c    | 45 ++++++++++++++++++++++++++
 hw/arm/virt.c               | 60 ++++++++++++++++++++++++++++++++++
 include/hw/acpi/aml-build.h | 26 +++++++++++++++
 include/hw/arm/virt.h       |  1 +
 5 files changed, 211 insertions(+)

-- 
2.1.0