dmaengine: idxd: add external module driver support for dsa_bus_type

Add support to allow an external driver to be registered to the
dsa_bus_type and also auto-loaded.
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Reviewed-by: Fenghua Yu <fenghua.yu@intel.com>
Acked-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/dma/idxd/bus.c

@@ -67,11 +67,17 @@ static void idxd_config_bus_remove(struct device *dev)
 	idxd_drv->remove(idxd_dev);
 }
 
+static int idxd_bus_uevent(const struct device *dev, struct kobj_uevent_env *env)
+{
+	return add_uevent_var(env, "MODALIAS=" IDXD_DEVICES_MODALIAS_FMT, 0);
+}
+
 struct bus_type dsa_bus_type = {
 	.name = "dsa",
 	.match = idxd_config_bus_match,
 	.probe = idxd_config_bus_probe,
 	.remove = idxd_config_bus_remove,
+	.uevent = idxd_bus_uevent,
 };
 EXPORT_SYMBOL_GPL(dsa_bus_type);
 

drivers/dma/idxd/idxd.h

@@ -655,6 +655,9 @@ static inline int idxd_wq_driver_name_match(struct idxd_wq *wq, struct device *d
 	return (strncmp(wq->driver_name, dev->driver->name, strlen(dev->driver->name)) == 0);
 }
 
+#define MODULE_ALIAS_IDXD_DEVICE(type) MODULE_ALIAS("idxd:t" __stringify(type) "*")
+#define IDXD_DEVICES_MODALIAS_FMT "idxd:t%d"
+
 int __must_check __idxd_driver_register(struct idxd_device_driver *idxd_drv,
 					struct module *module, const char *mod_name);
 #define idxd_driver_register(driver) \