[PATCH v17 01/18] EDAC: Add support for EDAC device features control

shiju.jose
2024-11-22T18:04:44Z

Add generic EDAC device feature controls supporting the registration
of RAS features available in the system. The driver exposes control
attributes for these features to userspace in
/sys/bus/edac/devices/<dev-name>/<ras-feature>/

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>
---
Documentation/edac/features.rst | 94 ++++++++++++++++++++++++++++++
Documentation/edac/index.rst | 10 ++++
drivers/edac/edac_device.c | 100 ++++++++++++++++++++++++++++++++
include/linux/edac.h | 28 +++++++++
4 files changed, 232 insertions(+)
create mode 100644 Documentation/edac/features.rst
create mode 100644 Documentation/edac/index.rst

diff --git a/Documentation/edac/features.rst b/Documentation/edac/features.rst
new file mode 100644
index 000000000000..e7a63146e708
--- /dev/null
+++ b/Documentation/edac/features.rst
@@ -0,0 +1,94 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+============================================
+Augmenting EDAC for controlling RAS features
+============================================
+
+Copyright (c) 2024 HiSilicon Limited.
+
+:Author: Shiju Jose <shiju.jose@huawei.com>
+:License: The GNU Free Documentation License, Version 1.2
+ (dual licensed under the GPL v2)
+:Original Reviewers:
+
+- Written for: 6.13
+
+Introduction
+------------
+The expansion of EDAC for controlling RAS features and exposing features
+control attributes to userspace via sysfs. Some Examples:
+
+* Scrub control
+
+* Error Check Scrub (ECS) control
+
+* ACPI RAS2 features
+
+* Post Package Repair (PPR) control
+
+* Memory Sparing Repair control etc.
+
+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, EDAC scrub, EDAC ECS, EDAC 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 exposes the features control attributes via
+the sysfs EDAC bus. 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.
diff --git a/Documentation/edac/index.rst b/Documentation/edac/index.rst
new file mode 100644
index 000000000000..b6c265a4cffb
--- /dev/null
+++ b/Documentation/edac/index.rst
@@ -0,0 +1,10 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+==============
+EDAC Subsystem
+==============
+
+.. toctree::
+ :maxdepth: 1
+
+ features
diff --git a/drivers/edac/edac_device.c b/drivers/edac/edac_device.c
index 621dc2a5d034..9fce46dd7405 100644
--- a/drivers/edac/edac_device.c
+++ b/drivers/edac/edac_device.c
@@ -570,3 +570,103 @@ void edac_device_handle_ue_count(struct edac_device_ctl_info *edac_dev,
block ? block->name : "N/A", count, msg);
}
EXPORT_SYMBOL_GPL(edac_device_handle_ue_count);
+
+static void edac_dev_release(struct device *dev)
+{
+ struct edac_dev_feat_ctx *ctx = container_of(dev, struct edac_dev_feat_ctx, dev);
+
+ kfree(ctx->dev.groups);
+ kfree(ctx);
+}
+
+const struct device_type edac_dev_type = {
+ .name = "edac_dev",
+ .release = edac_dev_release,
+};
+
+static void edac_dev_unreg(void *data)
+{
+ device_unregister(data);
+}
+
+/**
+ * edac_dev_register - register device for RAS features with EDAC
+ * @parent: parent device.
+ * @name: parent device's name.
+ * @private: parent driver's data to store in the context if any.
+ * @num_features: number of RAS features to register.
+ * @ras_features: list of RAS features to register.
+ *
+ * Return:
+ * * %0 - Success.
+ * * %-EINVAL - Invalid parameters passed.
+ * * %-ENOMEM - Dynamic memory allocation failed.
+ *
+ */
+int edac_dev_register(struct device *parent, char *name,
+ void *private, int num_features,
+ const struct edac_dev_feature *ras_features)
+{
+ const struct attribute_group **ras_attr_groups;
+ struct edac_dev_feat_ctx *ctx;
+ int attr_gcnt = 0;
+ int ret, feat;
+
+ if (!parent || !name || !num_features || !ras_features)
+ return -EINVAL;
+
+ /* Double parse to make space for attributes */
+ for (feat = 0; feat < num_features; feat++) {
+ switch (ras_features[feat].ft_type) {
+ /* Add feature specific code */
+ default:
+ return -EINVAL;
+ }
+ }
+
+ ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+ if (!ctx)
+ return -ENOMEM;
+
+ ras_attr_groups = kcalloc(attr_gcnt + 1, sizeof(*ras_attr_groups), GFP_KERNEL);
+ if (!ras_attr_groups) {
+ ret = -ENOMEM;
+ goto ctx_free;
+ }
+
+ attr_gcnt = 0;
+ for (feat = 0; feat < num_features; feat++, ras_features++) {
+ switch (ras_features->ft_type) {
+ /* Add feature specific code */
+ default:
+ ret = -EINVAL;
+ goto groups_free;
+ }
+ }
+
+ ctx->dev.parent = parent;
+ ctx->dev.bus = edac_get_sysfs_subsys();
+ ctx->dev.type = &edac_dev_type;
+ ctx->dev.groups = ras_attr_groups;
+ ctx->private = private;
+ dev_set_drvdata(&ctx->dev, ctx);
+
+ ret = dev_set_name(&ctx->dev, name);
+ if (ret)
+ goto groups_free;
+
+ ret = device_register(&ctx->dev);
+ if (ret) {
+ put_device(&ctx->dev);
+ return ret;
+ }
+
+ return devm_add_action_or_reset(parent, edac_dev_unreg, &ctx->dev);
+
+groups_free:
+ kfree(ras_attr_groups);
+ctx_free:
+ kfree(ctx);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(edac_dev_register);
diff --git a/include/linux/edac.h b/include/linux/edac.h
index b4ee8961e623..521b17113d4d 100644
--- a/include/linux/edac.h
+++ b/include/linux/edac.h
@@ -661,4 +661,32 @@ static inline struct dimm_info *edac_get_dimm(struct mem_ctl_info *mci,

return mci->dimms[index];
}
+
+#define EDAC_FEAT_NAME_LEN 128
+
+/* RAS feature type */
+enum edac_dev_feat {
+ RAS_FEAT_MAX
+};
+
+/* EDAC device feature information structure */
+struct edac_dev_data {
+ u8 instance;
+ void *private;
+};
+
+struct edac_dev_feat_ctx {
+ struct device dev;
+ void *private;
+};
+
+struct edac_dev_feature {
+ enum edac_dev_feat ft_type;
+ u8 instance;
+ void *ctx;
+};
+
+int edac_dev_register(struct device *parent, char *dev_name,
+ void *parent_pvt_data, int num_features,
+ const struct edac_dev_feature *ras_features);
#endif /* _LINUX_EDAC_H_ */
--
2.43.0