diff options
| author | Igor Mammedov <imammedo@redhat.com> | 2020-12-07 09:07:33 -0500 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2020-12-09 13:04:17 -0500 |
| commit | 1e6107d901ca3cb31ee3dbf3d55b1778682f0979 (patch) | |
| tree | c7ce20335d6dfce931c81b629c57ca379645e559 /docs | |
| parent | 0657c657eb37bb48bfd9fe3ae8a323ae3455f47b (diff) | |
acpi: cpuhp: introduce 'firmware performs eject' status/control bits
Adds bit #4 to status/control field of CPU hotplug MMIO interface.
New bit will be used OSPM to mark CPUs as pending for removal by firmware,
when it calls _EJ0 method on CPU device node. Later on, when firmware
sees this bit set, it will perform CPU eject which will clear bit #4
as well.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20201207140739.3829993-3-imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/specs/acpi_cpu_hotplug.txt | 19 |
1 files changed, 14 insertions, 5 deletions
diff --git a/docs/specs/acpi_cpu_hotplug.txt b/docs/specs/acpi_cpu_hotplug.txt index 9bb22d1270..9bd59ae0da 100644 --- a/docs/specs/acpi_cpu_hotplug.txt +++ b/docs/specs/acpi_cpu_hotplug.txt @@ -56,8 +56,11 @@ read access: no device check event to OSPM was issued. It's valid only when bit 0 is set. 2: Device remove event, used to distinguish device for which - no device eject request to OSPM was issued. - 3-7: reserved and should be ignored by OSPM + no device eject request to OSPM was issued. Firmware must + ignore this bit. + 3: reserved and should be ignored by OSPM + 4: if set to 1, OSPM requests firmware to perform device eject. + 5-7: reserved and should be ignored by OSPM [0x5-0x7] reserved [0x8] Command data: (DWORD access) contains 0 unless value last stored in 'Command field' is one of: @@ -79,10 +82,16 @@ write access: selected CPU device 2: if set to 1 clears device remove event, set by OSPM after it has emitted device eject request for the - selected CPU device + selected CPU device. 3: if set to 1 initiates device eject, set by OSPM when it - triggers CPU device removal and calls _EJ0 method - 4-7: reserved, OSPM must clear them before writing to register + triggers CPU device removal and calls _EJ0 method or by firmware + when bit #4 is set. In case bit #4 were set, it's cleared as + part of device eject. + 4: if set to 1, OSPM hands over device eject to firmware. + Firmware shall issue device eject request as described above + (bit #3) and OSPM should not touch device eject bit (#3) in case + it's asked firmware to perform CPU device eject. + 5-7: reserved, OSPM must clear them before writing to register [0x5] Command field: (1 byte access) value: 0: selects a CPU device with inserting/removing events and |