dmaengine: dsa: move dsa_bus_type out of idxd driver to standalone

In preparation for dsa_drv compat support to be built-in, move the bus
code to its own compilation unit. A follow-on patch adds the compat
implementation. Recall that the compat implementation allows for the
deprecated / omnibus dsa_drv binding scheme rather than the idiomatic
organization of a full fledged bus driver per driver type.

Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/162637468142.744545.2811632736881720857.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

1 files changed, 92 insertions, 0 deletions

diff --git a/drivers/dma/idxd/bus.c b/drivers/dma/idxd/bus.c
new file mode 100644
index 000000000000..02837f0fb3e4
--- /dev/null
+++ b/drivers/dma/idxd/bus.c
@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright(c) 2021 Intel Corporation. All rights rsvd. */
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include "idxd.h"
+
+
+int __idxd_driver_register(struct idxd_device_driver *idxd_drv, struct module *owner,
+			   const char *mod_name)
+{
+	struct device_driver *drv = &idxd_drv->drv;
+
+	if (!idxd_drv->type) {
+		pr_debug("driver type not set (%ps)\n", __builtin_return_address(0));
+		return -EINVAL;
+	}
+
+	drv->name = idxd_drv->name;
+	drv->bus = &dsa_bus_type;
+	drv->owner = owner;
+	drv->mod_name = mod_name;
+
+	return driver_register(drv);
+}
+EXPORT_SYMBOL_GPL(__idxd_driver_register);
+
+void idxd_driver_unregister(struct idxd_device_driver *idxd_drv)
+{
+	driver_unregister(&idxd_drv->drv);
+}
+EXPORT_SYMBOL_GPL(idxd_driver_unregister);
+
+static int idxd_config_bus_match(struct device *dev,
+				 struct device_driver *drv)
+{
+	struct idxd_device_driver *idxd_drv =
+		container_of(drv, struct idxd_device_driver, drv);
+	struct idxd_dev *idxd_dev = confdev_to_idxd_dev(dev);
+	int i = 0;
+
+	while (idxd_drv->type[i] != IDXD_DEV_NONE) {
+		if (idxd_dev->type == idxd_drv->type[i])
+			return 1;
+		i++;
+	}
+
+	return 0;
+}
+
+static int idxd_config_bus_probe(struct device *dev)
+{
+	struct idxd_device_driver *idxd_drv =
+		container_of(dev->driver, struct idxd_device_driver, drv);
+	struct idxd_dev *idxd_dev = confdev_to_idxd_dev(dev);
+
+	return idxd_drv->probe(idxd_dev);
+}
+
+static int idxd_config_bus_remove(struct device *dev)
+{
+	struct idxd_device_driver *idxd_drv =
+		container_of(dev->driver, struct idxd_device_driver, drv);
+	struct idxd_dev *idxd_dev = confdev_to_idxd_dev(dev);
+
+	idxd_drv->remove(idxd_dev);
+	return 0;
+}
+
+struct bus_type dsa_bus_type = {
+	.name = "dsa",
+	.match = idxd_config_bus_match,
+	.probe = idxd_config_bus_probe,
+	.remove = idxd_config_bus_remove,
+};
+EXPORT_SYMBOL_GPL(dsa_bus_type);
+
+static int __init dsa_bus_init(void)
+{
+	return bus_register(&dsa_bus_type);
+}
+module_init(dsa_bus_init);
+
+static void __exit dsa_bus_exit(void)
+{
+	bus_unregister(&dsa_bus_type);
+}
+module_exit(dsa_bus_exit);
+
+MODULE_DESCRIPTION("IDXD driver dsa_bus_type driver");
+MODULE_LICENSE("GPL v2");