dmaengine: idxd: iax bus removal

There is no need to have an additional bus for the IAX device. The removal
of IAX will change user ABI as /sys/bus/iax will no longer exist.
The iax device will be moved to the dsa bus. The device id for dsa and
iax will now be combined rather than unique for each device type in order
to accommodate the iax devices. This is in preparation for fixing the
sub-driver code for idxd. There's no hardware deployment for Sapphire
Rapids platform yet, which means that users have no reason to have
developed scripts against this ABI. There is some exposure to
released versions of accel-config, but those are being fixed up and
an accel-config upgrade is reasonable to get IAX support. As far as
accel-config is concerned IAX support starts when these devices appear
under /sys/bus/dsa, and old accel-config just assumes that an empty /
missing /sys/bus/iax just means a lack of platform support.

Fixes: f25b463883a8 ("dmaengine: idxd: add IAX configuration support in the IDXD driver")
Suggested-by: Dan Williams <[e-mail]>
Signed-off-by: Dave Jiang <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Vinod Koul <[e-mail]>

drivers/dma/idxd/cdev.c

···
 
 	device_initialize(dev);
 	dev->parent = &wq->conf_dev;
-	dev->bus = idxd_get_bus_type(idxd);
+	dev->bus = &dsa_bus_type;
 	dev->type = &idxd_cdev_device_type;
 	dev->devt = MKDEV(MAJOR(cdev_ctx->devt), minor);
 

drivers/dma/idxd/idxd.h

···
 extern struct bus_type iax_bus_type;
 
 extern bool support_enqcmd;
+extern struct ida idxd_ida;
 extern struct device_type dsa_device_type;
 extern struct device_type iax_device_type;
 extern struct device_type idxd_wq_device_type;
···
 	return wq->client_count;
 };
 
-struct ida *idxd_ida(struct idxd_device *idxd);
 const char *idxd_get_dev_name(struct idxd_device *idxd);
 int idxd_register_bus_type(void);
 void idxd_unregister_bus_type(void);
···
 void idxd_unregister_devices(struct idxd_device *idxd);
 int idxd_register_driver(void);
 void idxd_unregister_driver(void);
-struct bus_type *idxd_get_bus_type(struct idxd_device *idxd);
 struct device_type *idxd_get_device_type(struct idxd_device *idxd);
 
 /* device interrupt control */

drivers/dma/idxd/init.c

···
 #define DRV_NAME "idxd"
 
 bool support_enqcmd;
-
-static struct ida idxd_idas[IDXD_TYPE_MAX];
+DEFINE_IDA(idxd_ida);
 
 static struct pci_device_id idxd_pci_tbl[] = {
 	/* DSA ver 1.0 platforms */
···
 	"dsa",
 	"iax"
 };
-
-struct ida *idxd_ida(struct idxd_device *idxd)
-{
-	return &idxd_idas[idxd->type];
-}
 
 const char *idxd_get_dev_name(struct idxd_device *idxd)
 {
···
 		wq->idxd = idxd;
 		device_initialize(&wq->conf_dev);
 		wq->conf_dev.parent = &idxd->conf_dev;
-		wq->conf_dev.bus = idxd_get_bus_type(idxd);
+		wq->conf_dev.bus = &dsa_bus_type;
 		wq->conf_dev.type = &idxd_wq_device_type;
 		rc = dev_set_name(&wq->conf_dev, "wq%d.%d", idxd->id, wq->id);
 		if (rc < 0) {
···
 		group->idxd = idxd;
 		device_initialize(&group->conf_dev);
 		group->conf_dev.parent = &idxd->conf_dev;
-		group->conf_dev.bus = idxd_get_bus_type(idxd);
+		group->conf_dev.bus = &dsa_bus_type;
 		group->conf_dev.type = &idxd_group_device_type;
 		rc = dev_set_name(&group->conf_dev, "group%d.%d", idxd->id, group->id);
 		if (rc < 0) {
···
 
 	idxd->pdev = pdev;
 	idxd_set_type(idxd);
-	idxd->id = ida_alloc(idxd_ida(idxd), GFP_KERNEL);
+	idxd->id = ida_alloc(&idxd_ida, GFP_KERNEL);
 	if (idxd->id < 0)
 		return NULL;
 
 	device_initialize(&idxd->conf_dev);
 	idxd->conf_dev.parent = dev;
-	idxd->conf_dev.bus = idxd_get_bus_type(idxd);
+	idxd->conf_dev.bus = &dsa_bus_type;
 	idxd->conf_dev.type = idxd_get_device_type(idxd);
 	rc = dev_set_name(&idxd->conf_dev, "%s%d", idxd_get_dev_name(idxd), idxd->id);
 	if (rc < 0) {
···
 
 static int __init idxd_init_module(void)
 {
-	int err, i;
+	int err;
 
 	/*
 	 * If the CPU does not support MOVDIR64B or ENQCMDS, there's no point in
···
 		pr_warn("Platform does not have ENQCMD(S) support.\n");
 	else
 		support_enqcmd = true;
-
-	for (i = 0; i < IDXD_TYPE_MAX; i++)
-		ida_init(&idxd_idas[i]);
 
 	err = idxd_register_bus_type();
 	if (err < 0)

drivers/dma/idxd/sysfs.c

···
 	.shutdown = idxd_config_bus_shutdown,
 };
 
-struct bus_type iax_bus_type = {
-	.name = "iax",
-	.match = idxd_config_bus_match,
-	.probe = idxd_config_bus_probe,
-	.remove = idxd_config_bus_remove,
-	.shutdown = idxd_config_bus_shutdown,
-};
-
-static struct bus_type *idxd_bus_types[] = {
-	&dsa_bus_type,
-	&iax_bus_type
-};
-
 static struct idxd_device_driver dsa_drv = {
 	.drv = {
 		.name = "dsa",
···
 		.mod_name = KBUILD_MODNAME,
 	},
 };
-
-static struct idxd_device_driver iax_drv = {
-	.drv = {
-		.name = "iax",
-		.bus = &iax_bus_type,
-		.owner = THIS_MODULE,
-		.mod_name = KBUILD_MODNAME,
-	},
-};
-
-static struct idxd_device_driver *idxd_drvs[] = {
-	&dsa_drv,
-	&iax_drv
-};
-
-struct bus_type *idxd_get_bus_type(struct idxd_device *idxd)
-{
-	return idxd_bus_types[idxd->type];
-}
 
 struct device_type *idxd_get_device_type(struct idxd_device *idxd)
 {
···
 /* IDXD generic driver setup */
 int idxd_register_driver(void)
 {
-	int i, rc;
-
-	for (i = 0; i < IDXD_TYPE_MAX; i++) {
-		rc = driver_register(&idxd_drvs[i]->drv);
-		if (rc < 0)
-			goto drv_fail;
-	}
-
-	return 0;
-
-drv_fail:
-	while (--i >= 0)
-		driver_unregister(&idxd_drvs[i]->drv);
-	return rc;
+	return driver_register(&dsa_drv.drv);
 }
 
 void idxd_unregister_driver(void)
 {
-	int i;
-
-	for (i = 0; i < IDXD_TYPE_MAX; i++)
-		driver_unregister(&idxd_drvs[i]->drv);
+	driver_unregister(&dsa_drv.drv);
 }
 
 /* IDXD engine attributes */
···
 	kfree(idxd->wqs);
 	kfree(idxd->engines);
 	kfree(idxd->irq_entries);
-	ida_free(idxd_ida(idxd), idxd->id);
+	ida_free(&idxd_ida, idxd->id);
 	kfree(idxd);
 }
 
···
 
 int idxd_register_bus_type(void)
 {
-	int i, rc;
-
-	for (i = 0; i < IDXD_TYPE_MAX; i++) {
-		rc = bus_register(idxd_bus_types[i]);
-		if (rc < 0)
-			goto bus_err;
-	}
-
-	return 0;
-
-bus_err:
-	while (--i >= 0)
-		bus_unregister(idxd_bus_types[i]);
-	return rc;
+	return bus_register(&dsa_bus_type);
 }
 
 void idxd_unregister_bus_type(void)
 {
-	int i;
-
-	for (i = 0; i < IDXD_TYPE_MAX; i++)
-		bus_unregister(idxd_bus_types[i]);
+	bus_unregister(&dsa_bus_type);
 }