// SPDX-License-Identifier: GPL-2.0
/*
* bus driver for ccwgroup
*
* Copyright IBM Corp. 2002, 2012
*
* Author(s): Arnd Bergmann ([email protected])
* Cornelia Huck ([email protected])
*/
#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 const 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");
}
}
/**
* 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
* @call_gdrv: Call the registered gdrv set_offline function
*
* 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, bool call_gdrv)
{
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 (!call_gdrv) {
ret = 0;
goto offline;
}
if (gdrv->set_offline)
ret = gdrv->set_offline(gdev);
if (ret)
goto out;
offline:
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, true);
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 accidentally 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);
}
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_dev_attrs[] = {
&dev_attr_online.attr,
&dev_attr_ungroup.attr,
NULL,
};
ATTRIBUTE_GROUPS(ccwgroup_dev);
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)
{
struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
unsigned int i;
for (i = 0; i < gdev->count; i++) {
struct ccw_device *cdev = gdev->cdev[i];
unsigned long flags;
if (cdev) {
spin_lock_irqsave(cdev->ccwlock, flags);
if (dev_get_drvdata(&cdev->dev) == gdev)
dev_set_drvdata(&cdev->dev, NULL);
spin_unlock_irqrestore(cdev->ccwlock, flags);
put_device(&cdev->dev);
}
}
kfree(gdev);
}
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) {
while (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) {
while (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));
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:
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_UNBOUND_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 void ccwgroup_remove(struct device *dev)
{
struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
if (gdrv->remove)
gdrv->remove(gdev);
}
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 const struct bus_type ccwgroup_bus_type = {
.name = "ccwgroup",
.dev_groups = ccwgroup_dev_groups,
.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)
{
driver_unregister(&cdriver->driver);
}
EXPORT_SYMBOL(ccwgroup_driver_unregister);
/**
* 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_DESCRIPTION("ccwgroup bus driver");
MODULE_LICENSE("GPL");
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