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[Qemu-devel] [PATCH-for-4.2 v9 10/12] docs/specs: Add ACPI GED documenta
From: |
Shameer Kolothum |
Subject: |
[Qemu-devel] [PATCH-for-4.2 v9 10/12] docs/specs: Add ACPI GED documentation |
Date: |
Tue, 13 Aug 2019 22:05:37 +0100 |
Documents basic concepts of ACPI Generic Event device(GED)
and interface between QEMU and the ACPI BIOS.
Signed-off-by: Shameer Kolothum <address@hidden>
---
docs/specs/acpi_hw_reduced_hotplug.txt | 60 ++++++++++++++++++++++++++
1 file changed, 60 insertions(+)
create mode 100644 docs/specs/acpi_hw_reduced_hotplug.txt
diff --git a/docs/specs/acpi_hw_reduced_hotplug.txt
b/docs/specs/acpi_hw_reduced_hotplug.txt
new file mode 100644
index 0000000000..46839be5ff
--- /dev/null
+++ b/docs/specs/acpi_hw_reduced_hotplug.txt
@@ -0,0 +1,60 @@
+QEMU<->ACPI BIOS Generic Event Device interface
+
+The ACPI Generic Event Device (GED) is a HW reduced platform
+specific device introduced in ACPI v6.1 that handles all platform
+events, including the hotplug ones. GED is modelled as a device
+in the namespace with a _HID defined to be ACPI0013. This document
+describes the interface between QEMU and the ACPI BIOS.
+
+GED allows HW reduced platforms to handle interrupts in ACPI ASL
+statements. It follows a very similar approach like the _EVT method
+from GPIO events. All interrupts are listed in _CRS and the handler
+is written in _EVT method. However, Qemu implementation uses a single
+interrupt for the GED device, relying on IO memory region to communicate
+the type of device affected by the interrupt. This way, we can support
+up to 32 events with a unique interrupt.
+
+Here is an example.
+
+Device (\_SB.GED)
+{
+ Name (_HID, "ACPI0013")
+ Name (_UID, Zero)
+ Name (_CRS, ResourceTemplate ()
+ {
+ Interrupt (ResourceConsumer, Edge, ActiveHigh, Exclusive, ,, )
+ {
+ 0x00000029,
+ }
+ })
+ OperationRegion (EREG, SystemMemory, 0x09080000, 0x04)
+ Field (EREG, DWordAcc, NoLock, WriteAsZeros)
+ {
+ ESEL, 32
+ }
+ Method (_EVT, 1, Serialized)
+ {
+ Local0 = ESEL // ESEL = IO memory region which specifies the
+ // device type.
+ If (((Local0 & One) == One))
+ {
+ MethodEvent1()
+ }
+ If ((Local0 & 0x2) == 0x2)
+ {
+ MethodEvent2()
+ }
+ ...
+ }
+}
+
+GED IO interface (4 byte access):
+read access:
+ [0x0-0x3] Event selector bit field(32 bit) set by Qemu.
+ bits:
+ 1: Memory hotplug event
+ 2: System power down event
+ 3-31: Reserved
+
+write_access:
+ Nothing is expected to be written into GED IO memory
--
2.17.1
- [Qemu-devel] [PATCH-for-4.2 v9 02/12] hw/acpi: Do not create memory hotplug method when handler is not defined, (continued)
- [Qemu-devel] [PATCH-for-4.2 v9 02/12] hw/acpi: Do not create memory hotplug method when handler is not defined, Shameer Kolothum, 2019/08/13
- [Qemu-devel] [PATCH-for-4.2 v9 01/12] hw/acpi: Make ACPI IO address space configurable, Shameer Kolothum, 2019/08/13
- [Qemu-devel] [PATCH-for-4.2 v9 03/12] hw/acpi: Add ACPI Generic Event Device Support, Shameer Kolothum, 2019/08/13
- [Qemu-devel] [PATCH-for-4.2 v9 04/12] hw/arm/virt: Add memory hotplug framework, Shameer Kolothum, 2019/08/13
- [Qemu-devel] [PATCH-for-4.2 v9 05/12] hw/arm/virt: Add 4.2 machine type, Shameer Kolothum, 2019/08/13
- [Qemu-devel] [PATCH-for-4.2 v9 06/12] hw/arm/virt: Enable device memory cold/hot plug with ACPI boot, Shameer Kolothum, 2019/08/13
- [Qemu-devel] [PATCH-for-4.2 v9 08/12] hw/arm: Factor out powerdown notifier from GPIO, Shameer Kolothum, 2019/08/13
- [Qemu-devel] [PATCH-for-4.2 v9 09/12] hw/arm: Use GED for system_powerdown event, Shameer Kolothum, 2019/08/13
- [Qemu-devel] [PATCH-for-4.2 v9 07/12] hw/arm/virt-acpi-build: Add PC-DIMM in SRAT, Shameer Kolothum, 2019/08/13
- [Qemu-devel] [PATCH-for-4.2 v9 10/12] docs/specs: Add ACPI GED documentation,
Shameer Kolothum <=
- [Qemu-devel] [PATCH-for-4.2 v9 12/12] tests: Add bios tests to arm/virt, Shameer Kolothum, 2019/08/13
- [Qemu-devel] [PATCH-for-4.2 v9 11/12] tests: add dummy ACPI tables for arm/virt board, Shameer Kolothum, 2019/08/13
- Re: [Qemu-devel] [PATCH-for-4.2 v9 00/12] ARM virt: ACPI memory hotplug support, no-reply, 2019/08/14