Linux内核学习笔记——ACPI命名空间

所有定义块都加载到单个命名空间中。命名空间是由名称和路径标识的对象层次结构。以下命名约定适用于 ACPI 中的对象名称命名空间：

所有名称的长度均为 32 位。

名称的第一个字节必须是“A”-“Z”、“_”之一。

名称的每个剩余字节必须是“A”-“Z”、“0”之一 - ‘9’, ‘_’.

以“_”开头的名称由 ACPI 规范保留。

“”符号表示命名空间的根（即名称前缀为 ‘’ 是相对于命名空间根目录的）。

“^”符号表示当前命名空间节点的父节点（即以“^”开头的名称相对于当前命名空间节点）。

下图显示了一个示例 ACPI 命名空间：

+------+
| \    |                     Root
+------+|| +------++-| _PR  |                 Scope(_PR): the processor namespace| +------+|   ||   | +------+|   +-| CPU0 |             Processor(CPU0): the first processor|     +------+|| +------++-| _SB  |                 Scope(_SB): the system bus namespace| +------+|   ||   | +------+|   +-| LID0 |             Device(LID0); the lid device|   | +------+|   |   ||   |   | +------+|   |   +-| _HID |         Name(_HID, "PNP0C0D"): the hardware ID|   |   | +------+|   |   ||   |   | +------+|   |   +-| _STA |         Method(_STA): the status control method|   |     +------+|   ||   | +------+|   +-| PCI0 |             Device(PCI0); the PCI root bridge|     +------+|       ||       | +------+|       +-| _HID |         Name(_HID, "PNP0A08"): the hardware ID|       | +------+|       ||       | +------+|       +-| _CID |         Name(_CID, "PNP0A03"): the compatible ID|       | +------+|       ||       | +------+|       +-| RP03 |         Scope(RP03): the PCI0 power scope|       | +------+|       |   ||       |   | +------+|       |   +-| PXP3 |     PowerResource(PXP3): the PCI0 power resource|       |     +------+|       ||       | +------+|       +-| GFX0 |         Device(GFX0): the graphics adapter|         +------+|           ||           | +------+|           +-| _ADR |     Name(_ADR, 0x00020000): the PCI bus address|           | +------+|           ||           | +------+|           +-| DD01 |     Device(DD01): the LCD output device|             +------+|               ||               | +------+|               +-| _BCL | Method(_BCL): the backlight control method|                 +------+|| +------++-| _TZ  |                 Scope(_TZ): the thermal zone namespace| +------+|   ||   | +------+|   +-| FN00 |             PowerResource(FN00): the FAN0 power resource|   | +------+|   ||   | +------+|   +-| FAN0 |             Device(FAN0): the FAN0 cooling device|   | +------+|   |   ||   |   | +------+|   |   +-| _HID |         Name(_HID, "PNP0A0B"): the hardware ID|   |     +------+|   ||   | +------+|   +-| TZ00 |             ThermalZone(TZ00); the FAN thermal zone|     +------+|| +------++-| _GPE |                 Scope(_GPE): the GPE namespace+------+Figure 2. Example ACPI Namespace

Linux ACPI 设备树

结构acpi_device对象的 sysfs 层次结构对应于图 2 中所示的示例 ACPI 命名空间，添加了固定PWR_BUTTON/SLP_BUTTON设备如下所示：

+--------------+---+-----------------+
| LNXSYSTEM:00 | \ | acpi:LNXSYSTEM: |
+--------------+---+-----------------+|| +-------------+-----+----------------++-| LNXPWRBN:00 | N/A | acpi:LNXPWRBN: || +-------------+-----+----------------+|| +-------------+-----+----------------++-| LNXSLPBN:00 | N/A | acpi:LNXSLPBN: || +-------------+-----+----------------+|| +-----------+------------+--------------++-| LNXCPU:00 | \_PR_.CPU0 | acpi:LNXCPU: || +-----------+------------+--------------+|| +-------------+-------+----------------++-| LNXSYBUS:00 | \_SB_ | acpi:LNXSYBUS: || +-------------+-------+----------------+|   ||   | +- - - - - - - +- - - - - - +- - - - - - - -+|   +-| PNP0C0D:00 | \_SB_.LID0 | acpi:PNP0C0D: ||   | +- - - - - - - +- - - - - - +- - - - - - - -+|   ||   | +------------+------------+-----------------------+|   +-| PNP0A08:00 | \_SB_.PCI0 | acpi:PNP0A08:PNP0A03: ||     +------------+------------+-----------------------+|       ||       | +-----------+-----------------+-----+|       +-| device:00 | \_SB_.PCI0.RP03 | N/A ||       | +-----------+-----------------+-----+|       |   ||       |   | +-------------+----------------------+----------------+|       |   +-| LNXPOWER:00 | \_SB_.PCI0.RP03.PXP3 | acpi:LNXPOWER: ||       |     +-------------+----------------------+----------------+|       ||       | +-------------+-----------------+----------------+|       +-| LNXVIDEO:00 | \_SB_.PCI0.GFX0 | acpi:LNXVIDEO: ||         +-------------+-----------------+----------------+|           ||           | +-----------+-----------------+-----+|           +-| device:01 | \_SB_.PCI0.DD01 | N/A ||             +-----------+-----------------+-----+|| +-------------+-------+----------------++-| LNXSYBUS:01 | \_TZ_ | acpi:LNXSYBUS: |+-------------+-------+----------------+|| +-------------+------------+----------------++-| LNXPOWER:0a | \_TZ_.FN00 | acpi:LNXPOWER: || +-------------+------------+----------------+|| +------------+------------+---------------++-| PNP0C0B:00 | \_TZ_.FAN0 | acpi:PNP0C0B: || +------------+------------+---------------+|| +-------------+------------+----------------++-| LNXTHERM:00 | \_TZ_.TZ00 | acpi:LNXTHERM: |+-------------+------------+----------------+Figure 3. Example Linux ACPI Device Tree