Add read-only Acer A315-56 extended EC module

[celsonaemen]

Summary

Adds a model-specific, read-only semantic backend for the extended embedded-controller mailbox exposed by the Acer Aspire A315-56 ACPI firmware.

The module exposes one IOCTL that implements the semantic equivalent of EC0.FANG(index). Although the caller operation is a read, the firmware protocol necessarily writes the index and command fields before returning ERN1.

Hardware and firmware gate

Validated target:

• Acer Aspire A315-56
• mainboard Sleepy_IL
• Insyde BIOS V1.27
• Intel Core i3-1005G1, family 6/model 0x7E
• Intel LPC/eSPI PCI ID 8086:3482

The module refuses to load unless the CPU architecture/vendor/family/model and exact LPC vendor/device ID match.

Firmware reference

The transaction was derived from the decompiled DSDT path EC0.FANG -> EIDR/ERRD -> ERCD:

• ERIB: 0xFE0B0800 + 0x05D
• ECTB/ECTE: 0xFE0B0800 + 0x582
• ERN1: 0xFE0B0800 + 0x583
• ECMD: 0xFE0B0800 + 0x58B
• EDT1/EDT2: 0xFE0B0800 + 0x58C/0x58D
• extended-read command: ECMD 0xB0, EDT1 0x5F, EDT2 0

A sanitized hardware map and the reverse-engineering notes are available at:
https://github.com/celsonaemen/acer-a315-56-control/blob/main/docs/HARDWARE-MAP.md

Safety properties

• no arbitrary MMIO, EC, or fan-value write IOCTL
• one fixed 4 KiB MMIO mapping
• rejects an out-of-range 16-bit index
• returns STATUS_DEVICE_BUSY when ECTB or ECTE is already set
• documents the Access_EC user-mode mutant requirement
• one-second bounded poll with STATUS_IO_TIMEOUT
• best-effort ECTB cleanup on every post-acquisition exit
• LGPL-2.1-or-later with Doxygen documentation

Validation

• compiled with bundled Pawn 4.1.7152 and the repository CI flags
• all 23 top-level modules compiled successfully with no warnings
• git diff --check passed
• the unsigned module has not been loaded on the restricted production driver

The main review request is the ACPI/Acpi.sys concurrency model around the firmware mailbox and whether the hardware gate is sufficiently specific for an official signed build.

[namazso]

I changed this to draft, please test it before marking it as ready.

[celsonaemen]

A causa ficou fechada: dentro do CAB há quatro slots esperados (ARM64 normal/unrestricted e x64 normal/unrestricted), mas o quarto slot repete
exatamente o ARM64 unrestricted. O x64 normal existe; o x64 unrestricted não foi empacotado.

but i gona test it keep calm pls