3 files changed, 104 insertions, 0 deletions

diff --git a/drivers/base/Makefile b/drivers/base/Makefile
index b39ea3f59c9b..ff2696823f8d 100644
--- a/drivers/base/Makefile
+++ b/drivers/base/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_FW_LOADER)	+= firmware_class.o
 obj-$(CONFIG_NUMA)      += node.o
 obj-$(CONFIG_MEMORY_HOTPLUG_SPARSE) += memory.o
 obj-$(CONFIG_SMP)       += topology.o
+obj-$(CONFIG_MODULES)   += module.o
 obj-$(CONFIG_SYS_HYPERVISOR) += hypervisor.o
 
 ifeq ($(CONFIG_DEBUG_DRIVER),y)
diff --git a/drivers/base/base.h b/drivers/base/base.h
index ca6d273064f8..05472360f6a2 100644
--- a/drivers/base/base.h
+++ b/drivers/base/base.h
@@ -73,3 +73,12 @@ extern char *make_class_name(const char *name, struct kobject *kobj);
 extern int devres_release_all(struct device *dev);
 
 extern struct kset *devices_kset;
+
+#ifdef CONFIG_MODULES
+extern void module_add_driver(struct module *mod, struct device_driver *drv);
+extern void module_remove_driver(struct device_driver *drv);
+#else
+static inline void module_add_driver(struct module *mod,
+                                     struct device_driver *drv) { }
+static inline void module_remove_driver(struct device_driver *drv) { }
+#endif
diff --git a/drivers/base/module.c b/drivers/base/module.c
new file mode 100644
index 000000000000..cad07be5de1a
--- /dev/null
+++ b/drivers/base/module.c
@@ -0,0 +1,94 @@
+/*
+ * module.c - module sysfs fun for drivers
+ *
+ * This file is released under the GPLv2
+ *
+ */
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include "base.h"
+
+static char *make_driver_name(struct device_driver *drv)
+{
+        char *driver_name;
+
+        driver_name = kmalloc(strlen(drv->name) + strlen(drv->bus->name) + 2,
+                              GFP_KERNEL);
+        if (!driver_name)
+                return NULL;
+
+        sprintf(driver_name, "%s:%s", drv->bus->name, drv->name);
+        return driver_name;
+}
+
+static void module_create_drivers_dir(struct module_kobject *mk)
+{
+        if (!mk || mk->drivers_dir)
+                return;
+
+        mk->drivers_dir = kobject_create_and_add("drivers", &mk->kobj);
+}
+
+void module_add_driver(struct module *mod, struct device_driver *drv)
+{
+        char *driver_name;
+        int no_warn;
+        struct module_kobject *mk = NULL;
+
+        if (!drv)
+                return;
+
+        if (mod)
+                mk = &mod->mkobj;
+        else if (drv->mod_name) {
+                struct kobject *mkobj;
+
+                /* Lookup built-in module entry in /sys/modules */
+                mkobj = kset_find_obj(module_kset, drv->mod_name);
+                if (mkobj) {
+                        mk = container_of(mkobj, struct module_kobject, kobj);
+                        /* remember our module structure */
+                        drv->mkobj = mk;
+                        /* kset_find_obj took a reference */
+                        kobject_put(mkobj);
+                }
+        }
+
+        if (!mk)
+                return;
+
+        /* Don't check return codes; these calls are idempotent */
+        no_warn = sysfs_create_link(&drv->kobj, &mk->kobj, "module");
+        driver_name = make_driver_name(drv);
+        if (driver_name) {
+                module_create_drivers_dir(mk);
+                no_warn = sysfs_create_link(mk->drivers_dir, &drv->kobj,
+                                            driver_name);
+                kfree(driver_name);
+        }
+}
+
+void module_remove_driver(struct device_driver *drv)
+{
+        struct module_kobject *mk = NULL;
+        char *driver_name;
+
+        if (!drv)
+                return;
+
+        sysfs_remove_link(&drv->kobj, "module");
+
+        if (drv->owner)
+                mk = &drv->owner->mkobj;
+        else if (drv->mkobj)
+                mk = drv->mkobj;
+        if (mk && mk->drivers_dir) {
+                driver_name = make_driver_name(drv);
+                if (driver_name) {
+                        sysfs_remove_link(mk->drivers_dir, driver_name);
+                        kfree(driver_name);
+                }
+        }
+}