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2025-05-23EDAC: Update documentation for the CXL memory patrol scrub control featureShiju Jose1-0/+76
Update the Documentation/edac/scrub.rst to include use cases and policies for CXL memory device-based, CXL region-based patrol scrub control and CXL Error Check Scrub (ECS). Reviewed-by: Dave Jiang <dave.jiang@intel.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Shiju Jose <shiju.jose@huawei.com> Reviewed-by: Fan Ni <fan.ni@samsung.com> Reviewed-by: Alison Schofield <alison.schofield@intel.com> Acked-by: Dan Williams <dan.j.williams@intel.com> Link: https://patch.msgid.link/20250521124749.817-2-shiju.jose@huawei.com Signed-off-by: Dave Jiang <dave.jiang@intel.com>
2025-02-25EDAC: Add a Error Check Scrub control featureShiju Jose1-0/+2
Add an Error Check Scrub (ECS) control to manage a memory device's ECS feature. The ECS is a feature defined in JEDEC DDR5 SDRAM Specification (JESD79-5) and allows the DRAM to internally read, correct single-bit errors, and write back corrected data bits to the DRAM array while providing transparency to error counts. The DDR5 device contains a number of memory media Field Replaceable Units (FRU) per device. The DDR5 ECS feature and thus the ECS control driver supports configuring the ECS parameters per FRU. Memory devices support the ECS feature register with the EDAC device driver, which retrieves the ECS descriptor from the EDAC ECS driver. This driver exposes sysfs ECS control attributes to userspace via /sys/bus/edac/devices/<dev-name>/ecs_fruX/. The common sysfs ECS control interface abstracts the control of an arbitrary ECS functionality to a common set of functions. Support for the ECS feature is added separately because the control attributes of the DDR5 ECS feature differ from those of the scrub feature. The sysfs ECS attribute nodes are only present if the client driver has implemented the corresponding attribute callback function and passed the necessary operations to the EDAC RAS feature driver during registration. [ bp: Massage, fixup edac_dev_register() retvals. ] Co-developed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Shiju Jose <shiju.jose@huawei.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Fan Ni <fan.ni@samsung.com> Tested-by: Fan Ni <fan.ni@samsung.com> Link: https://lore.kernel.org/r/20250212143654.1893-4-shiju.jose@huawei.com
2025-02-25EDAC: Add scrub control featureShiju Jose1-0/+264
Add a scrub control to manage memory scrubbers in the system. Devices with a scrub feature register with the EDAC device driver which retrieves the scrub descriptor from the scrub driver and exposes the control attributes for a instance to userspace at /sys/bus/edac/devices/<dev-name>/scrubX/. The common sysfs scrub control interface abstracts the control of arbitrary scrubbing functionality into a common set of functions. The attribute nodes are only present if the client driver has implemented the corresponding attribute callback function and passed the operations to the device driver during registration. [ bp: Massage commit message, docs and code, simplify text a bit. Integrate fixup for: https://lore.kernel.org/r/202502251009.0sGkolEJ-lkp@intel.com Reported-by: kernel test robot <lkp@intel.com> Reported-by: Dan Carpenter <dan.carpenter@linaro.org> ] Co-developed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Shiju Jose <shiju.jose@huawei.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Tested-by: Daniel Ferguson <danielf@os.amperecomputing.com> Tested-by: Fan Ni <fan.ni@samsung.com> Link: https://lore.kernel.org/r/20250212143654.1893-3-shiju.jose@huawei.com