[PATCH] s390: ccwgroups.

ccwgroup bus driver.

The ccwgroup driver contains 'ccw_group' devices, which needed because of
strange hardware properties: Some device drivers need two or more
ccw_devices to make up a logical device and the user has to configure
which ones belong together. We have not found a way to represent this
correctly using the linux driver model, the current implementation
is about as good as it gets.

Authors: Arnd Bergmann <arndb@de.ibm.com>,

arch/s390/defconfig

@@ -143,6 +143,7 @@ CONFIG_HOTPLUG=y
 CONFIG_LCS=m
 CONFIG_CTC=m
 CONFIG_IUCV=m
+CONFIG_CCWGROUP=m
 
 #
 # Networking options

arch/s390x/defconfig

@@ -201,6 +201,7 @@ CONFIG_HOTPLUG=y
 CONFIG_LCS=m
 CONFIG_CTC=m
 CONFIG_IUCV=m
+CONFIG_CCWGROUP=m
 
 #
 # Networking options

drivers/s390/Kconfig

@@ -571,5 +571,10 @@ config IUCV
 	  vehicle networking under VM or VIF.  This option is also available
 	  as a module which will be called iucv.o. If unsure, say "Y".
 
+config CCWGROUP
+ 	tristate
+ 	depends on LCS || CTC
+	default m if LCS!=y && CTC!=y
+	default y if LCS=y || CTC=y
 endmenu
 

drivers/s390/cio/ccwgroup.c

+/*
+ *  drivers/s390/cio/ccwgroup.c
+ *  bus driver for ccwgroup
+ *   $Revision: 1.5 $
+ *
+ *    Copyright (C) 2002 IBM Deutschland Entwicklung GmbH,
+ *                       IBM Corporation
+ *    Author(s): Arnd Bergmann (arndb@de.ibm.com)
+ */
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/ctype.h>
+
+#include <asm/semaphore.h>
+#include <asm/ccwdev.h>
+#include <asm/ccwgroup.h>
+
+/* In Linux 2.4, we had a channel device layer called "chandev"
+ * that did all sorts of obscure stuff for networking devices.
+ * This is another driver that serves as a replacement for just
+ * one of its functions, namely the translation of single subchannels
+ * to devices that use multiple subchannels.
+ */
+
+/* a device matches a driver if all its slave devices match the same
+ * entry of the driver */
+static int
+ccwgroup_bus_match (struct device * dev, struct device_driver * drv)
+{
+	struct ccwgroup_device *gdev;
+	struct ccwgroup_driver *gdrv;
+
+	gdev = container_of(dev, struct ccwgroup_device, dev);
+	gdrv = container_of(drv, struct ccwgroup_driver, driver);
+
+	if (gdev->creator_id == gdrv->driver_id)
+		return 1;
+
+	return 0;
+}
+static int
+ccwgroup_hotplug (struct device *dev, char **envp, int num_envp, char *buffer,
+		  int buffer_size)
+{
+	/* TODO */
+	return 0;
+}
+
+static struct bus_type ccwgroup_bus_type = {
+	.name    = "ccwgroup",
+	.match   = ccwgroup_bus_match,
+	.hotplug = ccwgroup_hotplug,
+};
+
+static void
+ccwgroup_release (struct device *dev)
+{
+	struct ccwgroup_device *gdev;
+	int i;
+
+	gdev = to_ccwgroupdev(dev);
+
+	for (i = 0; i < gdev->count; i++)
+		put_device(&gdev->cdev[i]->dev);
+	kfree(gdev);
+}
+
+/*
+ * try to add a new ccwgroup device for one driver
+ * argc and argv[] are a list of bus_id's of devices
+ * belonging to the driver.
+ */
+int
+ccwgroup_create(struct device *root,
+		unsigned int creator_id,
+		struct ccw_driver *cdrv,
+		int argc, char *argv[])
+{
+	struct ccwgroup_device *gdev;
+	int i;
+
+	if (argc > 256) /* disallow dumb users */
+		return -EINVAL;
+
+	gdev = kmalloc(sizeof(*gdev) + argc*sizeof(gdev->cdev[0]), GFP_KERNEL);
+	if (!gdev)
+		return -ENOMEM;
+
+	for (i = 0; i < argc; i++) {
+		gdev->cdev[i] = get_ccwdev_by_busid(cdrv, argv[i]);
+
+		/* all devices have to be of the same type in
+		 * order to be grouped */
+		if (!gdev->cdev[i]
+		    || gdev->cdev[i]->id.driver_info !=
+		       gdev->cdev[0]->id.driver_info)
+			goto error;
+	}
+
+	*gdev = (struct ccwgroup_device) {
+		.creator_id = creator_id,
+		.count = argc,
+		.dev = {
+			.bus = &ccwgroup_bus_type,
+			.parent = root,
+			.release = &ccwgroup_release,
+		},
+	};
+
+	snprintf (gdev->dev.bus_id, BUS_ID_SIZE, "%s",
+			gdev->cdev[0]->dev.bus_id);
+
+	/* TODO: make symlinks for sysfs */
+	return device_register(&gdev->dev);
+
+error:
+	for (i = 0; i < argc; i++)
+		if (gdev->cdev[i])
+			put_device(&gdev->cdev[i]->dev);
+
+	kfree(gdev);
+
+	return -EINVAL;
+}
+
+static int __init
+init_ccwgroup (void)
+{
+	return bus_register (&ccwgroup_bus_type);
+}
+
+static void __exit
+cleanup_ccwgroup (void)
+{
+	bus_unregister (&ccwgroup_bus_type);
+}
+
+module_init(init_ccwgroup);
+module_exit(cleanup_ccwgroup);
+
+/************************** driver stuff ******************************/
+
+static int
+ccwgroup_set_online(struct ccwgroup_device *gdev)
+{
+	struct ccwgroup_driver *gdrv;
+	int ret;
+
+	if (gdev->state == CCWGROUP_ONLINE)
+		return 0;
+
+	if (!gdev->dev.driver)
+		return -EINVAL;
+
+	gdrv = to_ccwgroupdrv (gdev->dev.driver);
+	if ((ret = gdrv->set_online(gdev)))
+		return ret;
+
+	gdev->state = CCWGROUP_ONLINE;
+	return 0;
+}
+
+static int
+ccwgroup_set_offline(struct ccwgroup_device *gdev)
+{
+	struct ccwgroup_driver *gdrv;
+	int ret;
+
+	if (gdev->state == CCWGROUP_OFFLINE)
+		return 0;
+
+	if (!gdev->dev.driver)
+		return -EINVAL;
+
+	gdrv = to_ccwgroupdrv (gdev->dev.driver);
+	if ((ret = gdrv->set_offline(gdev)))
+		return ret;
+
+	gdev->state = CCWGROUP_OFFLINE;
+	return 0;
+}
+
+static ssize_t
+ccwgroup_online_store (struct device *dev, const char *buf, size_t count,
+			loff_t off)
+{
+	struct ccwgroup_device *gdev;
+	unsigned int value;
+
+	if (off)
+		return 0;
+
+	gdev = to_ccwgroupdev(dev);
+	if (!dev->driver)
+		return count;
+
+	value = simple_strtoul(buf, 0, 0);
+
+	if (value)
+		ccwgroup_set_online(gdev);
+	else
+		ccwgroup_set_offline(gdev);
+
+	return count;
+}
+
+static ssize_t
+ccwgroup_online_show (struct device *dev, char *buf, size_t count, loff_t off)
+{
+	int online;
+
+	if (off)
+		return 0;
+
+	online = (to_ccwgroupdev(dev)->state == CCWGROUP_ONLINE);
+
+	return snprintf(buf, count, online ? "1\n" : "0\n");
+}
+
+static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store);
+
+static int
+ccwgroup_probe (struct device *dev)
+{
+	struct ccwgroup_device *gdev;
+	struct ccwgroup_driver *gdrv;
+
+	int ret;
+
+	gdev = to_ccwgroupdev(dev);
+	gdrv = to_ccwgroupdrv(dev->driver);
+
+	if ((ret = device_create_file(dev, &dev_attr_online)))
+		return ret;
+
+	pr_debug("%s: device %s\n", __func__, gdev->dev.name);
+	ret = gdrv->probe ? gdrv->probe(gdev) : -ENODEV;
+	if (ret)
+		device_remove_file(dev, &dev_attr_online);
+
+	return ret;
+}
+
+static int
+ccwgroup_remove (struct device *dev)
+{
+	struct ccwgroup_device *gdev;
+	struct ccwgroup_driver *gdrv;
+	int ret;
+
+	gdev = to_ccwgroupdev(dev);
+	gdrv = to_ccwgroupdrv(dev->driver);
+
+	pr_debug("%s: device %s\n", __func__, gdev->dev.name);
+
+	device_remove_file(dev, &dev_attr_online);
+	ccwgroup_set_offline(gdev);
+
+	ret = (gdrv && gdrv->remove) ? gdrv->remove(gdev) : 0;
+
+	return ret;
+}
+
+int
+ccwgroup_driver_register (struct ccwgroup_driver *cdriver)
+{
+	/* register our new driver with the core */
+	cdriver->driver = (struct device_driver) {
+		.bus = &ccwgroup_bus_type,
+		.name = cdriver->name,
+		.probe = ccwgroup_probe,
+		.remove = ccwgroup_remove,
+	};
+
+	return driver_register(&cdriver->driver);
+}
+
+void
+ccwgroup_driver_unregister (struct ccwgroup_driver *cdriver)
+{
+	driver_unregister(&cdriver->driver);
+}
+
+int
+ccwgroup_probe_ccwdev(struct ccw_device *cdev)
+{
+	return 0;
+}
+
+int
+ccwgroup_remove_ccwdev(struct ccw_device *cdev)
+{
+	return 0;
+}
+
+MODULE_LICENSE("GPL");
+EXPORT_SYMBOL(ccwgroup_driver_register);
+EXPORT_SYMBOL(ccwgroup_driver_unregister);
+EXPORT_SYMBOL(ccwgroup_create);
+EXPORT_SYMBOL(ccwgroup_probe_ccwdev);
+EXPORT_SYMBOL(ccwgroup_remove_ccwdev);