@@ -146,4 +146,12 @@ config CXL_REGION_INVALIDATION_TEST
If unsure, or if this kernel is meant for production environments,
say N.
+config CXL_FEATURES
+ tristate "CXL: Features support"
+ default CXL_BUS
+ help
+ Enable CXL features support that are tied to a CXL mailbox.
+
+ If unsure say 'y'.
+
endif
@@ -7,15 +7,18 @@
# - 'mem' and 'pmem' before endpoint drivers so that memdevs are
# immediately enabled
# - 'pci' last, also mirrors the hardware enumeration hierarchy
+# - 'features' comes after pci device is enumerated
obj-y += core/
obj-$(CONFIG_CXL_PORT) += cxl_port.o
obj-$(CONFIG_CXL_ACPI) += cxl_acpi.o
obj-$(CONFIG_CXL_PMEM) += cxl_pmem.o
obj-$(CONFIG_CXL_MEM) += cxl_mem.o
obj-$(CONFIG_CXL_PCI) += cxl_pci.o
+obj-$(CONFIG_CXL_FEATURES) += cxl_features.o
cxl_port-y := port.o
cxl_acpi-y := acpi.o
cxl_pmem-y := pmem.o security.o
cxl_mem-y := mem.o
cxl_pci-y := pci.o
+cxl_features-y := features.o
@@ -14,5 +14,6 @@ cxl_core-y += pci.o
cxl_core-y += hdm.o
cxl_core-y += pmu.o
cxl_core-y += cdat.o
+cxl_core-y += features.o
cxl_core-$(CONFIG_TRACING) += trace.o
cxl_core-$(CONFIG_CXL_REGION) += region.o
@@ -9,6 +9,7 @@
extern const struct device_type cxl_nvdimm_bridge_type;
extern const struct device_type cxl_nvdimm_type;
extern const struct device_type cxl_pmu_type;
+extern const struct device_type cxl_features_type;
extern struct attribute_group cxl_base_attribute_group;
new file mode 100644
@@ -0,0 +1,71 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright(c) 2024-2025 Intel Corporation. All rights reserved. */
+#include <linux/device.h>
+#include "cxl.h"
+#include "core.h"
+
+#define CXL_FEATURE_MAX_DEVS 65536
+static DEFINE_IDA(cxl_features_ida);
+
+static void cxl_features_release(struct device *dev)
+{
+ struct cxl_features *features = to_cxl_features(dev);
+
+ ida_free(&cxl_features_ida, features->id);
+ kfree(features);
+}
+
+static void remove_features_dev(void *dev)
+{
+ device_unregister(dev);
+}
+
+const struct device_type cxl_features_type = {
+ .name = "features",
+ .release = cxl_features_release,
+};
+EXPORT_SYMBOL_NS_GPL(cxl_features_type, "CXL");
+
+struct cxl_features *cxl_features_alloc(struct cxl_mailbox *cxl_mbox,
+ struct device *parent)
+{
+ struct device *dev;
+ int rc;
+
+ struct cxl_features *features __free(kfree) =
+ kzalloc(sizeof(*features), GFP_KERNEL);
+ if (!features)
+ return ERR_PTR(-ENOMEM);
+
+ rc = ida_alloc_max(&cxl_features_ida, CXL_FEATURE_MAX_DEVS - 1,
+ GFP_KERNEL);
+ if (rc < 0)
+ return ERR_PTR(rc);
+
+ features->id = rc;
+ features->cxl_mbox = cxl_mbox;
+ dev = &features->dev;
+ device_initialize(dev);
+ device_set_pm_not_required(dev);
+ dev->parent = parent;
+ dev->bus = &cxl_bus_type;
+ dev->type = &cxl_features_type;
+ rc = dev_set_name(dev, "features%d", features->id);
+ if (rc)
+ goto err;
+
+ rc = device_add(dev);
+ if (rc)
+ goto err;
+
+ rc = devm_add_action_or_reset(parent, remove_features_dev, dev);
+ if (rc)
+ goto err;
+
+ return no_free_ptr(features);
+
+err:
+ put_device(dev);
+ return ERR_PTR(rc);
+}
+EXPORT_SYMBOL_NS_GPL(cxl_features_alloc, "CXL");
@@ -74,6 +74,9 @@ static int cxl_device_id(const struct device *dev)
return CXL_DEVICE_REGION;
if (dev->type == &cxl_pmu_type)
return CXL_DEVICE_PMU;
+ if (dev->type == &cxl_features_type)
+ return CXL_DEVICE_FEATURES;
+
return 0;
}
@@ -855,6 +855,7 @@ void cxl_driver_unregister(struct cxl_driver *cxl_drv);
#define CXL_DEVICE_PMEM_REGION 7
#define CXL_DEVICE_DAX_REGION 8
#define CXL_DEVICE_PMU 9
+#define CXL_DEVICE_FEATURES 10
#define MODULE_ALIAS_CXL(type) MODULE_ALIAS("cxl:t" __stringify(type) "*")
#define CXL_MODALIAS_FMT "cxl:t%d"
new file mode 100644
@@ -0,0 +1,44 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright(c) 2024,2025 Intel Corporation. All rights reserved. */
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <cxl/features.h>
+
+#include "cxl.h"
+
+static int cxl_features_probe(struct device *dev)
+{
+ struct cxl_features *features = to_cxl_features(dev);
+ struct cxl_features_state *cfs __free(kfree) =
+ kzalloc(sizeof(*cfs), GFP_KERNEL);
+
+ if (!cfs)
+ return -ENOMEM;
+
+ cfs->features = features;
+ dev_set_drvdata(dev, no_free_ptr(cfs));
+
+ return 0;
+}
+
+static void cxl_features_remove(struct device *dev)
+{
+ struct cxl_features_state *cfs = dev_get_drvdata(dev);
+
+ kfree(cfs);
+}
+
+static struct cxl_driver cxl_features_driver = {
+ .name = "cxl_features",
+ .probe = cxl_features_probe,
+ .remove = cxl_features_remove,
+ .id = CXL_DEVICE_FEATURES,
+};
+
+module_cxl_driver(cxl_features_driver);
+
+MODULE_DESCRIPTION("CXL: Features");
+MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS("CXL");
+MODULE_ALIAS_CXL(CXL_DEVICE_FEATURES);
@@ -386,6 +386,21 @@ static int cxl_pci_mbox_send(struct cxl_mailbox *cxl_mbox,
return rc;
}
+static int cxl_pci_setup_features(struct cxl_memdev_state *mds)
+{
+ struct cxl_dev_state *cxlds = &mds->cxlds;
+ struct cxl_mailbox *cxl_mbox = &cxlds->cxl_mbox;
+ struct cxl_features *features;
+
+ features = cxl_features_alloc(cxl_mbox, cxlds->dev);
+ if (IS_ERR(features))
+ return PTR_ERR(features);
+
+ cxl_mbox->features = features;
+
+ return 0;
+}
+
static int cxl_pci_setup_mailbox(struct cxl_memdev_state *mds, bool irq_avail)
{
struct cxl_dev_state *cxlds = &mds->cxlds;
@@ -980,6 +995,10 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
if (rc)
return rc;
+ rc = cxl_pci_setup_features(mds);
+ if (rc)
+ return rc;
+
rc = cxl_set_timestamp(mds);
if (rc)
return rc;
new file mode 100644
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* Copyright(c) 2024-2025 Intel Corporation. */
+#ifndef __CXL_FEATURES_H__
+#define __CXL_FEATURES_H__
+
+struct cxl_mailbox;
+
+struct cxl_features {
+ int id;
+ struct device dev;
+ struct cxl_mailbox *cxl_mbox;
+};
+#define to_cxl_features(dev) container_of(dev, struct cxl_features, dev)
+
+struct cxl_features_state {
+ struct cxl_features *features;
+ int num_features;
+};
+
+struct cxl_features *cxl_features_alloc(struct cxl_mailbox *cxl_mbox,
+ struct device *parent);
+
+#endif
@@ -3,6 +3,7 @@
#ifndef __CXL_MBOX_H__
#define __CXL_MBOX_H__
#include <linux/rcuwait.h>
+#include <cxl/features.h>
#include <uapi/linux/cxl_mem.h>
/**
@@ -50,6 +51,7 @@ struct cxl_mbox_cmd {
* (CXL 3.1 8.2.8.4.3 Mailbox Capabilities Register)
* @mbox_mutex: mutex protects device mailbox and firmware
* @mbox_wait: rcuwait for mailbox
+ * @features: pointer to cxl_features device
* @mbox_send: @dev specific transport for transmitting mailbox commands
*/
struct cxl_mailbox {
@@ -59,6 +61,7 @@ struct cxl_mailbox {
size_t payload_size;
struct mutex mbox_mutex; /* lock to protect mailbox context */
struct rcuwait mbox_wait;
+ struct cxl_features *features;
int (*mbox_send)(struct cxl_mailbox *cxl_mbox, struct cxl_mbox_cmd *cmd);
};
@@ -61,6 +61,7 @@ cxl_core-y += $(CXL_CORE_SRC)/pci.o
cxl_core-y += $(CXL_CORE_SRC)/hdm.o
cxl_core-y += $(CXL_CORE_SRC)/pmu.o
cxl_core-y += $(CXL_CORE_SRC)/cdat.o
+cxl_core-y += $(CXL_CORE_SRC)/features.o
cxl_core-$(CONFIG_TRACING) += $(CXL_CORE_SRC)/trace.o
cxl_core-$(CONFIG_CXL_REGION) += $(CXL_CORE_SRC)/region.o
cxl_core-y += config_check.o