| .. SPDX-License-Identifier: GPL-2.0 OR GFDL-1.2-no-invariants-or-later |
| |
| ================= |
| EDAC/RAS features |
| ================= |
| |
| Copyright (c) 2024-2025 HiSilicon Limited. |
| |
| :Author: Shiju Jose <shiju.jose@huawei.com> |
| :License: The GNU Free Documentation License, Version 1.2 without |
| Invariant Sections, Front-Cover Texts nor Back-Cover Texts. |
| (dual licensed under the GPL v2) |
| |
| - Written for: 6.15 |
| |
| Introduction |
| ------------ |
| |
| EDAC/RAS components plugging and high-level design: |
| |
| 1. Scrub control |
| |
| 2. Error Check Scrub (ECS) control |
| |
| 3. ACPI RAS2 features |
| |
| 4. Post Package Repair (PPR) control |
| |
| 5. Memory Sparing Repair control |
| |
| High level design is illustrated in the following diagram:: |
| |
| +-----------------------------------------------+ |
| | Userspace - Rasdaemon | |
| | +-------------+ | |
| | | RAS CXL mem | +---------------+ | |
| | |error handler|---->| | | |
| | +-------------+ | RAS dynamic | | |
| | +-------------+ | scrub, memory | | |
| | | RAS memory |---->| repair control| | |
| | |error handler| +----|----------+ | |
| | +-------------+ | | |
| +--------------------------|--------------------+ |
| | |
| | |
| +-------------------------------|------------------------------+ |
| | Kernel EDAC extension for | controlling RAS Features | |
| |+------------------------------|----------------------------+ | |
| || EDAC Core Sysfs EDAC| Bus | | |
| || +--------------------------|---------------------------+| | |
| || |/sys/bus/edac/devices/<dev>/scrubX/ | | EDAC device || | |
| || |/sys/bus/edac/devices/<dev>/ecsX/ |<->| EDAC MC || | |
| || |/sys/bus/edac/devices/<dev>/repairX | | EDAC sysfs || | |
| || +---------------------------|--------------------------+| | |
| || EDAC|Bus | | |
| || | | | |
| || +----------+ Get feature | Get feature | | |
| || | | desc +---------|------+ desc +----------+ | | |
| || |EDAC scrub|<-----| EDAC device | | | | | |
| || +----------+ | driver- RAS |----->| EDAC mem | | | |
| || +----------+ | feature control| | repair | | | |
| || | |<-----| | +----------+ | | |
| || |EDAC ECS | +---------|------+ | | |
| || +----------+ Register RAS|features | | |
| || ______________________|_____________ | | |
| |+---------|---------------|------------------|--------------+ | |
| | +-------|----+ +-------|-------+ +----|----------+ | |
| | | | | CXL mem driver| | Client driver | | |
| | | ACPI RAS2 | | scrub, ECS, | | memory repair | | |
| | | driver | | sparing, PPR | | features | | |
| | +-----|------+ +-------|-------+ +------|--------+ | |
| | | | | | |
| +--------|-----------------|--------------------|--------------+ |
| | | | |
| +--------|-----------------|--------------------|--------------+ |
| | +---|-----------------|--------------------|-------+ | |
| | | | | |
| | | Platform HW and Firmware | | |
| | +--------------------------------------------------+ | |
| +--------------------------------------------------------------+ |
| |
| |
| 1. EDAC Features components - Create feature-specific descriptors. For |
| example: scrub, ECS, memory repair in the above diagram. |
| |
| 2. EDAC device driver for controlling RAS Features - Get feature's attribute |
| descriptors from EDAC RAS feature component and registers device's RAS |
| features with EDAC bus and expose the features control attributes via |
| sysfs. For example, /sys/bus/edac/devices/<dev-name>/<feature>X/ |
| |
| 3. RAS dynamic feature controller - Userspace sample modules in rasdaemon for |
| dynamic scrub/repair control to issue scrubbing/repair when excess number |
| of corrected memory errors are reported in a short span of time. |
| |
| RAS features |
| ------------ |
| 1. Memory Scrub |
| |
| Memory scrub features are documented in `Documentation/edac/scrub.rst`. |
| |
| 2. Memory Repair |
| |
| Memory repair features are documented in `Documentation/edac/memory_repair.rst`. |
