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>

drivers/dma/Kconfig

@@ -277,6 +277,10 @@ config INTEL_IDMA64
 	  Enable DMA support for Intel Low Power Subsystem such as found on
 	  Intel Skylake PCH.
 
+config INTEL_IDXD_BUS
+	tristate
+	default INTEL_IDXD
+
 config INTEL_IDXD
 	tristate "Intel Data Accelerators support"
 	depends on PCI && X86_64 && !UML

drivers/dma/Makefile

@@ -41,7 +41,7 @@ obj-$(CONFIG_IMX_DMA) += imx-dma.o
 obj-$(CONFIG_IMX_SDMA) += imx-sdma.o
 obj-$(CONFIG_INTEL_IDMA64) += idma64.o
 obj-$(CONFIG_INTEL_IOATDMA) += ioat/
-obj-$(CONFIG_INTEL_IDXD) += idxd/
+obj-y += idxd/
 obj-$(CONFIG_INTEL_IOP_ADMA) += iop-adma.o
 obj-$(CONFIG_K3_DMA) += k3dma.o
 obj-$(CONFIG_LPC18XX_DMAMUX) += lpc18xx-dmamux.o

drivers/dma/idxd/Makefile

@@ -1,4 +1,9 @@
+ccflags-y += -DDEFAULT_SYMBOL_NAMESPACE=IDXD
+
 obj-$(CONFIG_INTEL_IDXD) += idxd.o
 idxd-y := init.o irq.o device.o sysfs.o submit.o dma.o cdev.o
 
 idxd-$(CONFIG_INTEL_IDXD_PERFMON) += perfmon.o
+
+obj-$(CONFIG_INTEL_IDXD_BUS) += idxd_bus.o
+idxd_bus-y := bus.o

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");

drivers/dma/idxd/init.c

@@ -26,6 +26,7 @@
 MODULE_VERSION(IDXD_DRIVER_VERSION);
 MODULE_LICENSE("GPL v2");
 MODULE_AUTHOR("Intel Corporation");
+MODULE_IMPORT_NS(IDXD);
 
 static bool sva = true;
 module_param(sva, bool, 0644);
@@ -836,10 +837,6 @@ static int __init idxd_init_module(void)
 
 	perfmon_init();
 
-	err = idxd_register_bus_type();
-	if (err < 0)
-		return err;
-
 	err = idxd_driver_register(&idxd_drv);
 	if (err < 0)
 		goto err_idxd_driver_register;
@@ -877,7 +874,6 @@ err_idxd_user_driver_register:
 err_idxd_dmaengine_driver_register:
 	idxd_driver_unregister(&idxd_drv);
 err_idxd_driver_register:
-	idxd_unregister_bus_type();
 	return err;
 }
 module_init(idxd_init_module);
@@ -890,30 +886,6 @@ static void __exit idxd_exit_module(void)
 	idxd_driver_unregister(&dsa_drv);
 	pci_unregister_driver(&idxd_pci_driver);
 	idxd_cdev_remove();
-	idxd_unregister_bus_type();
 	perfmon_exit();
 }
 module_exit(idxd_exit_module);
-
-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);
-}
-
-void idxd_driver_unregister(struct idxd_device_driver *idxd_drv)
-{
-	driver_unregister(&idxd_drv->drv);
-}

drivers/dma/idxd/sysfs.c

@@ -16,49 +16,6 @@ static char *idxd_wq_type_names[] = {
 	[IDXD_WQT_USER]		= "user",
 };
 
-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,
-};
-
 static int idxd_dsa_drv_probe(struct idxd_dev *idxd_dev)
 {
 	if (is_idxd_dev(idxd_dev))