Enable devices on the 'cxl' bus to be attached to drivers. The initial
user of this functionality is a driver for an 'nvdimm-bridge' device
that anchors a libnvdimm hierarchy attached to CXL persistent memory
resources. Other device types that will leverage this include:
cxl_port: map and use component register functionality (HDM Decoders)
cxl_nvdimm: translate CXL memory expander endpoints to libnvdimm
'nvdimm' objects
cxl_region: translate CXL interleave sets to libnvdimm 'region' objects
The pairing of devices to drivers is handled through the cxl_device_id()
matching to cxl_driver.id values. A cxl_device_id() of '0' indicates no
driver support.
In addition to ->match(), ->probe(), and ->remove() support for the
'cxl' bus introduce MODULE_ALIAS_CXL() to autoload modules containing
cxl-drivers. Drivers are added in follow-on changes.
Reviewed-by: Jonathan Cameron <[email protected]>
Link: https://lore.kernel.org/r/162336396329.2462439.16556923116284874437.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <[email protected]>
---
drivers/cxl/core.c | 73 ++++++++++++++++++++++++++++++++++++++++++++++++++++
drivers/cxl/cxl.h | 22 ++++++++++++++++
2 files changed, 95 insertions(+)
diff --git a/drivers/cxl/core.c b/drivers/cxl/core.c
index c613dc795498..68d6afea363b 100644
--- a/drivers/cxl/core.c
+++ b/drivers/cxl/core.c
@@ -767,8 +767,81 @@ int cxl_map_device_regs(struct pci_dev *pdev,
}
EXPORT_SYMBOL_GPL(cxl_map_device_regs);
+/**
+ * __cxl_driver_register - register a driver for the cxl bus
+ * @cxl_drv: cxl driver structure to attach
+ * @owner: owning module/driver
+ * @modname: KBUILD_MODNAME for parent driver
+ */
+int __cxl_driver_register(struct cxl_driver *cxl_drv, struct module *owner,
+ const char *modname)
+{
+ if (!cxl_drv->probe) {
+ pr_debug("%s ->probe() must be specified\n", modname);
+ return -EINVAL;
+ }
+
+ if (!cxl_drv->name) {
+ pr_debug("%s ->name must be specified\n", modname);
+ return -EINVAL;
+ }
+
+ if (!cxl_drv->id) {
+ pr_debug("%s ->id must be specified\n", modname);
+ return -EINVAL;
+ }
+
+ cxl_drv->drv.bus = &cxl_bus_type;
+ cxl_drv->drv.owner = owner;
+ cxl_drv->drv.mod_name = modname;
+ cxl_drv->drv.name = cxl_drv->name;
+
+ return driver_register(&cxl_drv->drv);
+}
+EXPORT_SYMBOL_GPL(__cxl_driver_register);
+
+void cxl_driver_unregister(struct cxl_driver *cxl_drv)
+{
+ driver_unregister(&cxl_drv->drv);
+}
+EXPORT_SYMBOL_GPL(cxl_driver_unregister);
+
+static int cxl_device_id(struct device *dev)
+{
+ return 0;
+}
+
+static int cxl_bus_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+ return add_uevent_var(env, "MODALIAS=" CXL_MODALIAS_FMT,
+ cxl_device_id(dev));
+}
+
+static int cxl_bus_match(struct device *dev, struct device_driver *drv)
+{
+ return cxl_device_id(dev) == to_cxl_drv(drv)->id;
+}
+
+static int cxl_bus_probe(struct device *dev)
+{
+ return to_cxl_drv(dev->driver)->probe(dev);
+}
+
+static int cxl_bus_remove(struct device *dev)
+{
+ struct cxl_driver *cxl_drv = to_cxl_drv(dev->driver);
+
+ if (cxl_drv->remove)
+ cxl_drv->remove(dev);
+ return 0;
+}
+
struct bus_type cxl_bus_type = {
.name = "cxl",
+ .uevent = cxl_bus_uevent,
+ .match = cxl_bus_match,
+ .probe = cxl_bus_probe,
+ .remove = cxl_bus_remove,
};
EXPORT_SYMBOL_GPL(cxl_bus_type);
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index 97a273ae3947..a6f8e7097ea2 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -268,4 +268,26 @@ devm_cxl_add_passthrough_decoder(struct device *host, struct cxl_port *port)
}
extern struct bus_type cxl_bus_type;
+
+struct cxl_driver {
+ const char *name;
+ int (*probe)(struct device *dev);
+ void (*remove)(struct device *dev);
+ struct device_driver drv;
+ int id;
+};
+
+static inline struct cxl_driver *to_cxl_drv(struct device_driver *drv)
+{
+ return container_of(drv, struct cxl_driver, drv);
+}
+
+int __cxl_driver_register(struct cxl_driver *cxl_drv, struct module *owner,
+ const char *modname);
+#define cxl_driver_register(x) __cxl_driver_register(x, THIS_MODULE, KBUILD_MODNAME)
+void cxl_driver_unregister(struct cxl_driver *cxl_drv);
+
+#define MODULE_ALIAS_CXL(type) MODULE_ALIAS("cxl:t" __stringify(type) "*")
+#define CXL_MODALIAS_FMT "cxl:t%d"
+
#endif /* __CXL_H__ */