[PATCH v6 5/5] fw_cfg: document ACPI device node information
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STALE3914d
REVIEWED: 2 (0M)
From: Gabriel L. Somlo <hidden>
Date: 2016-01-28 03:10:51
Also in:
linux-devicetree, lkml, qemu-devel
Subsystem:
the rest · Maintainer:
Linus Torvalds
2 review trailers.
Signed-off-by: Gabriel Somlo <redacted> Reviewed-by: Laszlo Ersek <redacted> Reviewed-by: Marc Marí <redacted> --- docs/specs/fw_cfg.txt | 9 +++++++++ 1 file changed, 9 insertions(+)
diff --git a/docs/specs/fw_cfg.txt b/docs/specs/fw_cfg.txt
index 2099ad9..5414140 100644
--- a/docs/specs/fw_cfg.txt
+++ b/docs/specs/fw_cfg.txt@@ -84,6 +84,15 @@ Selector Register address: Base + 8 (2 bytes) Data Register address: Base + 0 (8 bytes) DMA Address address: Base + 16 (8 bytes) +== ACPI Interface == + +The fw_cfg device is defined with ACPI ID "QEMU0002". Since we expect +ACPI tables to be passed into the guest through the fw_cfg device itself, +the guest-side firmware can not use ACPI to find fw_cfg. However, once the +firmware is finished setting up ACPI tables and hands control over to the +guest kernel, the latter can use the fw_cfg ACPI node for a more accurate +inventory of in-use IOport or MMIO regions. + == Firmware Configuration Items == === Signature (Key 0x0000, FW_CFG_SIGNATURE) ===
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2.4.3