diff options
Diffstat (limited to 'drivers/s390/cio/ccwgroup.c')
| -rw-r--r-- | drivers/s390/cio/ccwgroup.c | 603 |
1 files changed, 603 insertions, 0 deletions
diff --git a/drivers/s390/cio/ccwgroup.c b/drivers/s390/cio/ccwgroup.c new file mode 100644 index 000000000..483a9ecfc --- /dev/null +++ b/drivers/s390/cio/ccwgroup.c @@ -0,0 +1,603 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * bus driver for ccwgroup + * + * Copyright IBM Corp. 2002, 2012 + * + * Author(s): Arnd Bergmann (arndb@de.ibm.com) + * Cornelia Huck (cornelia.huck@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 <linux/dcache.h> + +#include <asm/cio.h> +#include <asm/ccwdev.h> +#include <asm/ccwgroup.h> + +#include "device.h" + +#define CCW_BUS_ID_SIZE 10 + +/* 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. + */ + +static struct bus_type ccwgroup_bus_type; + +static void __ccwgroup_remove_symlinks(struct ccwgroup_device *gdev) +{ + int i; + char str[16]; + + for (i = 0; i < gdev->count; i++) { + sprintf(str, "cdev%d", i); + sysfs_remove_link(&gdev->dev.kobj, str); + sysfs_remove_link(&gdev->cdev[i]->dev.kobj, "group_device"); + } +} + +/* + * Remove references from ccw devices to ccw group device and from + * ccw group device to ccw devices. + */ +static void __ccwgroup_remove_cdev_refs(struct ccwgroup_device *gdev) +{ + struct ccw_device *cdev; + int i; + + for (i = 0; i < gdev->count; i++) { + cdev = gdev->cdev[i]; + if (!cdev) + continue; + spin_lock_irq(cdev->ccwlock); + dev_set_drvdata(&cdev->dev, NULL); + spin_unlock_irq(cdev->ccwlock); + gdev->cdev[i] = NULL; + put_device(&cdev->dev); + } +} + +/** + * ccwgroup_set_online() - enable a ccwgroup device + * @gdev: target ccwgroup device + * + * This function attempts to put the ccwgroup device into the online state. + * Returns: + * %0 on success and a negative error value on failure. + */ +int ccwgroup_set_online(struct ccwgroup_device *gdev) +{ + struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver); + int ret = -EINVAL; + + if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0) + return -EAGAIN; + if (gdev->state == CCWGROUP_ONLINE) + goto out; + if (gdrv->set_online) + ret = gdrv->set_online(gdev); + if (ret) + goto out; + + gdev->state = CCWGROUP_ONLINE; +out: + atomic_set(&gdev->onoff, 0); + return ret; +} +EXPORT_SYMBOL(ccwgroup_set_online); + +/** + * ccwgroup_set_offline() - disable a ccwgroup device + * @gdev: target ccwgroup device + * + * This function attempts to put the ccwgroup device into the offline state. + * Returns: + * %0 on success and a negative error value on failure. + */ +int ccwgroup_set_offline(struct ccwgroup_device *gdev) +{ + struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver); + int ret = -EINVAL; + + if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0) + return -EAGAIN; + if (gdev->state == CCWGROUP_OFFLINE) + goto out; + if (gdrv->set_offline) + ret = gdrv->set_offline(gdev); + if (ret) + goto out; + + gdev->state = CCWGROUP_OFFLINE; +out: + atomic_set(&gdev->onoff, 0); + return ret; +} +EXPORT_SYMBOL(ccwgroup_set_offline); + +static ssize_t ccwgroup_online_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct ccwgroup_device *gdev = to_ccwgroupdev(dev); + unsigned long value; + int ret; + + device_lock(dev); + if (!dev->driver) { + ret = -EINVAL; + goto out; + } + + ret = kstrtoul(buf, 0, &value); + if (ret) + goto out; + + if (value == 1) + ret = ccwgroup_set_online(gdev); + else if (value == 0) + ret = ccwgroup_set_offline(gdev); + else + ret = -EINVAL; +out: + device_unlock(dev); + return (ret == 0) ? count : ret; +} + +static ssize_t ccwgroup_online_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct ccwgroup_device *gdev = to_ccwgroupdev(dev); + int online; + + online = (gdev->state == CCWGROUP_ONLINE) ? 1 : 0; + + return scnprintf(buf, PAGE_SIZE, "%d\n", online); +} + +/* + * Provide an 'ungroup' attribute so the user can remove group devices no + * longer needed or accidentially created. Saves memory :) + */ +static void ccwgroup_ungroup(struct ccwgroup_device *gdev) +{ + mutex_lock(&gdev->reg_mutex); + if (device_is_registered(&gdev->dev)) { + __ccwgroup_remove_symlinks(gdev); + device_unregister(&gdev->dev); + __ccwgroup_remove_cdev_refs(gdev); + } + mutex_unlock(&gdev->reg_mutex); +} + +static ssize_t ccwgroup_ungroup_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct ccwgroup_device *gdev = to_ccwgroupdev(dev); + int rc = 0; + + /* Prevent concurrent online/offline processing and ungrouping. */ + if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0) + return -EAGAIN; + if (gdev->state != CCWGROUP_OFFLINE) { + rc = -EINVAL; + goto out; + } + + if (device_remove_file_self(dev, attr)) + ccwgroup_ungroup(gdev); + else + rc = -ENODEV; +out: + if (rc) { + /* Release onoff "lock" when ungrouping failed. */ + atomic_set(&gdev->onoff, 0); + return rc; + } + return count; +} +static DEVICE_ATTR(ungroup, 0200, NULL, ccwgroup_ungroup_store); +static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store); + +static struct attribute *ccwgroup_attrs[] = { + &dev_attr_online.attr, + &dev_attr_ungroup.attr, + NULL, +}; +static struct attribute_group ccwgroup_attr_group = { + .attrs = ccwgroup_attrs, +}; +static const struct attribute_group *ccwgroup_attr_groups[] = { + &ccwgroup_attr_group, + NULL, +}; + +static void ccwgroup_ungroup_workfn(struct work_struct *work) +{ + struct ccwgroup_device *gdev = + container_of(work, struct ccwgroup_device, ungroup_work); + + ccwgroup_ungroup(gdev); + put_device(&gdev->dev); +} + +static void ccwgroup_release(struct device *dev) +{ + kfree(to_ccwgroupdev(dev)); +} + +static int __ccwgroup_create_symlinks(struct ccwgroup_device *gdev) +{ + char str[16]; + int i, rc; + + for (i = 0; i < gdev->count; i++) { + rc = sysfs_create_link(&gdev->cdev[i]->dev.kobj, + &gdev->dev.kobj, "group_device"); + if (rc) { + for (--i; i >= 0; i--) + sysfs_remove_link(&gdev->cdev[i]->dev.kobj, + "group_device"); + return rc; + } + } + for (i = 0; i < gdev->count; i++) { + sprintf(str, "cdev%d", i); + rc = sysfs_create_link(&gdev->dev.kobj, + &gdev->cdev[i]->dev.kobj, str); + if (rc) { + for (--i; i >= 0; i--) { + sprintf(str, "cdev%d", i); + sysfs_remove_link(&gdev->dev.kobj, str); + } + for (i = 0; i < gdev->count; i++) + sysfs_remove_link(&gdev->cdev[i]->dev.kobj, + "group_device"); + return rc; + } + } + return 0; +} + +static int __get_next_id(const char **buf, struct ccw_dev_id *id) +{ + unsigned int cssid, ssid, devno; + int ret = 0, len; + char *start, *end; + + start = (char *)*buf; + end = strchr(start, ','); + if (!end) { + /* Last entry. Strip trailing newline, if applicable. */ + end = strchr(start, '\n'); + if (end) + *end = '\0'; + len = strlen(start) + 1; + } else { + len = end - start + 1; + end++; + } + if (len <= CCW_BUS_ID_SIZE) { + if (sscanf(start, "%2x.%1x.%04x", &cssid, &ssid, &devno) != 3) + ret = -EINVAL; + } else + ret = -EINVAL; + + if (!ret) { + id->ssid = ssid; + id->devno = devno; + } + *buf = end; + return ret; +} + +/** + * ccwgroup_create_dev() - create and register a ccw group device + * @parent: parent device for the new device + * @gdrv: driver for the new group device + * @num_devices: number of slave devices + * @buf: buffer containing comma separated bus ids of slave devices + * + * Create and register a new ccw group device as a child of @parent. Slave + * devices are obtained from the list of bus ids given in @buf. + * Returns: + * %0 on success and an error code on failure. + * Context: + * non-atomic + */ +int ccwgroup_create_dev(struct device *parent, struct ccwgroup_driver *gdrv, + int num_devices, const char *buf) +{ + struct ccwgroup_device *gdev; + struct ccw_dev_id dev_id; + int rc, i; + + if (num_devices < 1) + return -EINVAL; + + gdev = kzalloc(struct_size(gdev, cdev, num_devices), GFP_KERNEL); + if (!gdev) + return -ENOMEM; + + atomic_set(&gdev->onoff, 0); + mutex_init(&gdev->reg_mutex); + mutex_lock(&gdev->reg_mutex); + INIT_WORK(&gdev->ungroup_work, ccwgroup_ungroup_workfn); + gdev->count = num_devices; + gdev->dev.bus = &ccwgroup_bus_type; + gdev->dev.parent = parent; + gdev->dev.release = ccwgroup_release; + device_initialize(&gdev->dev); + + for (i = 0; i < num_devices && buf; i++) { + rc = __get_next_id(&buf, &dev_id); + if (rc != 0) + goto error; + gdev->cdev[i] = get_ccwdev_by_dev_id(&dev_id); + /* + * All devices have to be of the same type in + * order to be grouped. + */ + if (!gdev->cdev[i] || !gdev->cdev[i]->drv || + gdev->cdev[i]->drv != gdev->cdev[0]->drv || + gdev->cdev[i]->id.driver_info != + gdev->cdev[0]->id.driver_info) { + rc = -EINVAL; + goto error; + } + /* Don't allow a device to belong to more than one group. */ + spin_lock_irq(gdev->cdev[i]->ccwlock); + if (dev_get_drvdata(&gdev->cdev[i]->dev)) { + spin_unlock_irq(gdev->cdev[i]->ccwlock); + rc = -EINVAL; + goto error; + } + dev_set_drvdata(&gdev->cdev[i]->dev, gdev); + spin_unlock_irq(gdev->cdev[i]->ccwlock); + } + /* Check for sufficient number of bus ids. */ + if (i < num_devices) { + rc = -EINVAL; + goto error; + } + /* Check for trailing stuff. */ + if (i == num_devices && buf && strlen(buf) > 0) { + rc = -EINVAL; + goto error; + } + /* Check if the devices are bound to the required ccw driver. */ + if (gdrv && gdrv->ccw_driver && + gdev->cdev[0]->drv != gdrv->ccw_driver) { + rc = -EINVAL; + goto error; + } + + dev_set_name(&gdev->dev, "%s", dev_name(&gdev->cdev[0]->dev)); + gdev->dev.groups = ccwgroup_attr_groups; + + if (gdrv) { + gdev->dev.driver = &gdrv->driver; + rc = gdrv->setup ? gdrv->setup(gdev) : 0; + if (rc) + goto error; + } + rc = device_add(&gdev->dev); + if (rc) + goto error; + rc = __ccwgroup_create_symlinks(gdev); + if (rc) { + device_del(&gdev->dev); + goto error; + } + mutex_unlock(&gdev->reg_mutex); + return 0; +error: + for (i = 0; i < num_devices; i++) + if (gdev->cdev[i]) { + spin_lock_irq(gdev->cdev[i]->ccwlock); + if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev) + dev_set_drvdata(&gdev->cdev[i]->dev, NULL); + spin_unlock_irq(gdev->cdev[i]->ccwlock); + put_device(&gdev->cdev[i]->dev); + gdev->cdev[i] = NULL; + } + mutex_unlock(&gdev->reg_mutex); + put_device(&gdev->dev); + return rc; +} +EXPORT_SYMBOL(ccwgroup_create_dev); + +static int ccwgroup_notifier(struct notifier_block *nb, unsigned long action, + void *data) +{ + struct ccwgroup_device *gdev = to_ccwgroupdev(data); + + if (action == BUS_NOTIFY_UNBIND_DRIVER) { + get_device(&gdev->dev); + schedule_work(&gdev->ungroup_work); + } + + return NOTIFY_OK; +} + +static struct notifier_block ccwgroup_nb = { + .notifier_call = ccwgroup_notifier +}; + +static int __init init_ccwgroup(void) +{ + int ret; + + ret = bus_register(&ccwgroup_bus_type); + if (ret) + return ret; + + ret = bus_register_notifier(&ccwgroup_bus_type, &ccwgroup_nb); + if (ret) + bus_unregister(&ccwgroup_bus_type); + + return ret; +} + +static void __exit cleanup_ccwgroup(void) +{ + bus_unregister_notifier(&ccwgroup_bus_type, &ccwgroup_nb); + bus_unregister(&ccwgroup_bus_type); +} + +module_init(init_ccwgroup); +module_exit(cleanup_ccwgroup); + +/************************** driver stuff ******************************/ + +static int ccwgroup_remove(struct device *dev) +{ + struct ccwgroup_device *gdev = to_ccwgroupdev(dev); + struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver); + + if (!dev->driver) + return 0; + if (gdrv->remove) + gdrv->remove(gdev); + + return 0; +} + +static void ccwgroup_shutdown(struct device *dev) +{ + struct ccwgroup_device *gdev = to_ccwgroupdev(dev); + struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver); + + if (!dev->driver) + return; + if (gdrv->shutdown) + gdrv->shutdown(gdev); +} + +static struct bus_type ccwgroup_bus_type = { + .name = "ccwgroup", + .remove = ccwgroup_remove, + .shutdown = ccwgroup_shutdown, +}; + +bool dev_is_ccwgroup(struct device *dev) +{ + return dev->bus == &ccwgroup_bus_type; +} +EXPORT_SYMBOL(dev_is_ccwgroup); + +/** + * ccwgroup_driver_register() - register a ccw group driver + * @cdriver: driver to be registered + * + * This function is mainly a wrapper around driver_register(). + */ +int ccwgroup_driver_register(struct ccwgroup_driver *cdriver) +{ + /* register our new driver with the core */ + cdriver->driver.bus = &ccwgroup_bus_type; + + return driver_register(&cdriver->driver); +} +EXPORT_SYMBOL(ccwgroup_driver_register); + +/** + * ccwgroup_driver_unregister() - deregister a ccw group driver + * @cdriver: driver to be deregistered + * + * This function is mainly a wrapper around driver_unregister(). + */ +void ccwgroup_driver_unregister(struct ccwgroup_driver *cdriver) +{ + struct device *dev; + + /* We don't want ccwgroup devices to live longer than their driver. */ + while ((dev = driver_find_next_device(&cdriver->driver, NULL))) { + struct ccwgroup_device *gdev = to_ccwgroupdev(dev); + + ccwgroup_ungroup(gdev); + put_device(dev); + } + driver_unregister(&cdriver->driver); +} +EXPORT_SYMBOL(ccwgroup_driver_unregister); + +/** + * get_ccwgroupdev_by_busid() - obtain device from a bus id + * @gdrv: driver the device is owned by + * @bus_id: bus id of the device to be searched + * + * This function searches all devices owned by @gdrv for a device with a bus + * id matching @bus_id. + * Returns: + * If a match is found, its reference count of the found device is increased + * and it is returned; else %NULL is returned. + */ +struct ccwgroup_device *get_ccwgroupdev_by_busid(struct ccwgroup_driver *gdrv, + char *bus_id) +{ + struct device *dev; + + dev = driver_find_device_by_name(&gdrv->driver, bus_id); + + return dev ? to_ccwgroupdev(dev) : NULL; +} +EXPORT_SYMBOL_GPL(get_ccwgroupdev_by_busid); + +/** + * ccwgroup_probe_ccwdev() - probe function for slave devices + * @cdev: ccw device to be probed + * + * This is a dummy probe function for ccw devices that are slave devices in + * a ccw group device. + * Returns: + * always %0 + */ +int ccwgroup_probe_ccwdev(struct ccw_device *cdev) +{ + return 0; +} +EXPORT_SYMBOL(ccwgroup_probe_ccwdev); + +/** + * ccwgroup_remove_ccwdev() - remove function for slave devices + * @cdev: ccw device to be removed + * + * This is a remove function for ccw devices that are slave devices in a ccw + * group device. It sets the ccw device offline and also deregisters the + * embedding ccw group device. + */ +void ccwgroup_remove_ccwdev(struct ccw_device *cdev) +{ + struct ccwgroup_device *gdev; + + /* Ignore offlining errors, device is gone anyway. */ + ccw_device_set_offline(cdev); + /* If one of its devices is gone, the whole group is done for. */ + spin_lock_irq(cdev->ccwlock); + gdev = dev_get_drvdata(&cdev->dev); + if (!gdev) { + spin_unlock_irq(cdev->ccwlock); + return; + } + /* Get ccwgroup device reference for local processing. */ + get_device(&gdev->dev); + spin_unlock_irq(cdev->ccwlock); + /* Unregister group device. */ + ccwgroup_ungroup(gdev); + /* Release ccwgroup device reference for local processing. */ + put_device(&gdev->dev); +} +EXPORT_SYMBOL(ccwgroup_remove_ccwdev); +MODULE_LICENSE("GPL"); |