nubus: Add support for the driver model

This patch brings basic support for the Linux Driver Model to the
NuBus subsystem.

For flexibility, the matching of boards with drivers is left up to the
drivers. This is also the approach taken by NetBSD. A board may have
many functions, and drivers may have to consider many functional
resources and board resources in order to match a device.

This implementation does not bind drivers to resources (nor does it bind
many drivers to the same board). Apple's NuBus declaration ROM design
is flexible enough to allow that, but I don't see a need to support it
as we don't use the "slot zero" resources (in the main logic board ROM).

Eliminate the global nubus_boards linked list by rewriting the procfs
board iterator around bus_for_each_dev(). Hence the nubus device refcount
can be used to determine the lifespan of board objects.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

1 files changed, 117 insertions, 0 deletions

diff --git a/drivers/nubus/bus.c b/drivers/nubus/bus.c
new file mode 100644
index 000000000000..d306c348c857
--- /dev/null
+++ b/drivers/nubus/bus.c
@@ -0,0 +1,117 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Bus implementation for the NuBus subsystem.
+//
+// Copyright (C) 2017 Finn Thain
+
+#include <linux/device.h>
+#include <linux/list.h>
+#include <linux/nubus.h>
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+
+#define to_nubus_board(d)       container_of(d, struct nubus_board, dev)
+#define to_nubus_driver(d)      container_of(d, struct nubus_driver, driver)
+
+static int nubus_bus_match(struct device *dev, struct device_driver *driver)
+{
+	return 1;
+}
+
+static int nubus_device_probe(struct device *dev)
+{
+	struct nubus_driver *ndrv = to_nubus_driver(dev->driver);
+	int err = -ENODEV;
+
+	if (ndrv->probe)
+		err = ndrv->probe(to_nubus_board(dev));
+	return err;
+}
+
+static int nubus_device_remove(struct device *dev)
+{
+	struct nubus_driver *ndrv = to_nubus_driver(dev->driver);
+	int err = -ENODEV;
+
+	if (dev->driver && ndrv->remove)
+		err = ndrv->remove(to_nubus_board(dev));
+	return err;
+}
+
+struct bus_type nubus_bus_type = {
+	.name		= "nubus",
+	.match		= nubus_bus_match,
+	.probe		= nubus_device_probe,
+	.remove		= nubus_device_remove,
+};
+EXPORT_SYMBOL(nubus_bus_type);
+
+int nubus_driver_register(struct nubus_driver *ndrv)
+{
+	ndrv->driver.bus = &nubus_bus_type;
+	return driver_register(&ndrv->driver);
+}
+EXPORT_SYMBOL(nubus_driver_register);
+
+void nubus_driver_unregister(struct nubus_driver *ndrv)
+{
+	driver_unregister(&ndrv->driver);
+}
+EXPORT_SYMBOL(nubus_driver_unregister);
+
+static struct device nubus_parent = {
+	.init_name	= "nubus",
+};
+
+int __init nubus_bus_register(void)
+{
+	int err;
+
+	err = device_register(&nubus_parent);
+	if (err)
+		return err;
+
+	err = bus_register(&nubus_bus_type);
+	if (!err)
+		return 0;
+
+	device_unregister(&nubus_parent);
+	return err;
+}
+
+static void nubus_device_release(struct device *dev)
+{
+	struct nubus_board *board = to_nubus_board(dev);
+	struct nubus_rsrc *fres, *tmp;
+
+	list_for_each_entry_safe(fres, tmp, &nubus_func_rsrcs, list)
+		if (fres->board == board) {
+			list_del(&fres->list);
+			kfree(fres);
+		}
+	kfree(board);
+}
+
+int nubus_device_register(struct nubus_board *board)
+{
+	board->dev.parent = &nubus_parent;
+	board->dev.release = nubus_device_release;
+	board->dev.bus = &nubus_bus_type;
+	dev_set_name(&board->dev, "slot.%X", board->slot);
+	return device_register(&board->dev);
+}
+
+static int nubus_print_device_name_fn(struct device *dev, void *data)
+{
+	struct nubus_board *board = to_nubus_board(dev);
+	struct seq_file *m = data;
+
+	seq_printf(m, "Slot %X: %s\n", board->slot, board->name);
+	return 0;
+}
+
+int nubus_proc_show(struct seq_file *m, void *data)
+{
+	return bus_for_each_dev(&nubus_bus_type, NULL, m,
+				nubus_print_device_name_fn);
+}