![Sebastian Ott](/assets/img/avatar_default.png)
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
704 lines
16 KiB
C
704 lines
16 KiB
C
/*
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* bus driver for ccwgroup
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*
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* Copyright IBM Corp. 2002, 2009
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*
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* Author(s): Arnd Bergmann (arndb@de.ibm.com)
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* Cornelia Huck (cornelia.huck@de.ibm.com)
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*/
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#include <linux/module.h>
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#include <linux/errno.h>
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#include <linux/slab.h>
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#include <linux/list.h>
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#include <linux/device.h>
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#include <linux/init.h>
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#include <linux/ctype.h>
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#include <linux/dcache.h>
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#include <asm/ccwdev.h>
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#include <asm/ccwgroup.h>
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#define CCW_BUS_ID_SIZE 20
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/* In Linux 2.4, we had a channel device layer called "chandev"
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* that did all sorts of obscure stuff for networking devices.
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* This is another driver that serves as a replacement for just
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* one of its functions, namely the translation of single subchannels
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* to devices that use multiple subchannels.
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*/
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/* a device matches a driver if all its slave devices match the same
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* entry of the driver */
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static int
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ccwgroup_bus_match (struct device * dev, struct device_driver * drv)
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{
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struct ccwgroup_device *gdev;
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struct ccwgroup_driver *gdrv;
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gdev = to_ccwgroupdev(dev);
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gdrv = to_ccwgroupdrv(drv);
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if (gdev->creator_id == gdrv->driver_id)
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return 1;
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return 0;
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}
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static int
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ccwgroup_uevent (struct device *dev, struct kobj_uevent_env *env)
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{
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/* TODO */
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return 0;
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}
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static struct bus_type ccwgroup_bus_type;
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static void
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__ccwgroup_remove_symlinks(struct ccwgroup_device *gdev)
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{
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int i;
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char str[8];
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for (i = 0; i < gdev->count; i++) {
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sprintf(str, "cdev%d", i);
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sysfs_remove_link(&gdev->dev.kobj, str);
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sysfs_remove_link(&gdev->cdev[i]->dev.kobj, "group_device");
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}
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}
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/*
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* Provide an 'ungroup' attribute so the user can remove group devices no
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* longer needed or accidentially created. Saves memory :)
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*/
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static void ccwgroup_ungroup_callback(struct device *dev)
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{
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struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
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mutex_lock(&gdev->reg_mutex);
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if (device_is_registered(&gdev->dev)) {
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__ccwgroup_remove_symlinks(gdev);
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device_unregister(dev);
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}
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mutex_unlock(&gdev->reg_mutex);
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}
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static ssize_t
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ccwgroup_ungroup_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
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{
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struct ccwgroup_device *gdev;
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int rc;
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gdev = to_ccwgroupdev(dev);
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/* Prevent concurrent online/offline processing and ungrouping. */
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if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
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return -EAGAIN;
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if (gdev->state != CCWGROUP_OFFLINE) {
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rc = -EINVAL;
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goto out;
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}
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/* Note that we cannot unregister the device from one of its
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* attribute methods, so we have to use this roundabout approach.
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*/
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rc = device_schedule_callback(dev, ccwgroup_ungroup_callback);
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out:
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if (rc) {
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if (rc != -EAGAIN)
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/* Release onoff "lock" when ungrouping failed. */
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atomic_set(&gdev->onoff, 0);
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return rc;
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}
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return count;
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}
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static DEVICE_ATTR(ungroup, 0200, NULL, ccwgroup_ungroup_store);
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static void
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ccwgroup_release (struct device *dev)
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{
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struct ccwgroup_device *gdev;
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int i;
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gdev = to_ccwgroupdev(dev);
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for (i = 0; i < gdev->count; i++) {
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if (gdev->cdev[i]) {
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if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev)
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dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
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put_device(&gdev->cdev[i]->dev);
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}
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}
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kfree(gdev);
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}
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static int
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__ccwgroup_create_symlinks(struct ccwgroup_device *gdev)
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{
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char str[8];
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int i, rc;
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for (i = 0; i < gdev->count; i++) {
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rc = sysfs_create_link(&gdev->cdev[i]->dev.kobj, &gdev->dev.kobj,
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"group_device");
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if (rc) {
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for (--i; i >= 0; i--)
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sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
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"group_device");
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return rc;
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}
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}
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for (i = 0; i < gdev->count; i++) {
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sprintf(str, "cdev%d", i);
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rc = sysfs_create_link(&gdev->dev.kobj, &gdev->cdev[i]->dev.kobj,
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str);
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if (rc) {
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for (--i; i >= 0; i--) {
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sprintf(str, "cdev%d", i);
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sysfs_remove_link(&gdev->dev.kobj, str);
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}
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for (i = 0; i < gdev->count; i++)
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sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
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"group_device");
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return rc;
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}
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}
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return 0;
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}
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static int __get_next_bus_id(const char **buf, char *bus_id)
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{
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int rc, len;
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char *start, *end;
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start = (char *)*buf;
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end = strchr(start, ',');
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if (!end) {
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/* Last entry. Strip trailing newline, if applicable. */
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end = strchr(start, '\n');
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if (end)
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*end = '\0';
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len = strlen(start) + 1;
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} else {
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len = end - start + 1;
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end++;
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}
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if (len < CCW_BUS_ID_SIZE) {
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strlcpy(bus_id, start, len);
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rc = 0;
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} else
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rc = -EINVAL;
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*buf = end;
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return rc;
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}
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static int __is_valid_bus_id(char bus_id[CCW_BUS_ID_SIZE])
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{
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int cssid, ssid, devno;
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/* Must be of form %x.%x.%04x */
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if (sscanf(bus_id, "%x.%1x.%04x", &cssid, &ssid, &devno) != 3)
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return 0;
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return 1;
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}
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/**
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* ccwgroup_create_from_string() - create and register a ccw group device
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* @root: parent device for the new device
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* @creator_id: identifier of creating driver
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* @cdrv: ccw driver of slave devices
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* @num_devices: number of slave devices
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* @buf: buffer containing comma separated bus ids of slave devices
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*
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* Create and register a new ccw group device as a child of @root. Slave
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* devices are obtained from the list of bus ids given in @buf and must all
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* belong to @cdrv.
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* Returns:
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* %0 on success and an error code on failure.
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* Context:
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* non-atomic
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*/
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int ccwgroup_create_from_string(struct device *root, unsigned int creator_id,
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struct ccw_driver *cdrv, int num_devices,
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const char *buf)
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{
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struct ccwgroup_device *gdev;
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int rc, i;
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char tmp_bus_id[CCW_BUS_ID_SIZE];
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const char *curr_buf;
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gdev = kzalloc(sizeof(*gdev) + num_devices * sizeof(gdev->cdev[0]),
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GFP_KERNEL);
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if (!gdev)
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return -ENOMEM;
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atomic_set(&gdev->onoff, 0);
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mutex_init(&gdev->reg_mutex);
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mutex_lock(&gdev->reg_mutex);
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gdev->creator_id = creator_id;
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gdev->count = num_devices;
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gdev->dev.bus = &ccwgroup_bus_type;
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gdev->dev.parent = root;
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gdev->dev.release = ccwgroup_release;
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device_initialize(&gdev->dev);
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curr_buf = buf;
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for (i = 0; i < num_devices && curr_buf; i++) {
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rc = __get_next_bus_id(&curr_buf, tmp_bus_id);
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if (rc != 0)
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goto error;
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if (!__is_valid_bus_id(tmp_bus_id)) {
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rc = -EINVAL;
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goto error;
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}
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gdev->cdev[i] = get_ccwdev_by_busid(cdrv, tmp_bus_id);
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/*
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* All devices have to be of the same type in
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* order to be grouped.
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*/
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if (!gdev->cdev[i]
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|| gdev->cdev[i]->id.driver_info !=
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gdev->cdev[0]->id.driver_info) {
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rc = -EINVAL;
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goto error;
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}
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/* Don't allow a device to belong to more than one group. */
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if (dev_get_drvdata(&gdev->cdev[i]->dev)) {
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rc = -EINVAL;
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goto error;
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}
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dev_set_drvdata(&gdev->cdev[i]->dev, gdev);
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}
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/* Check for sufficient number of bus ids. */
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if (i < num_devices && !curr_buf) {
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rc = -EINVAL;
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goto error;
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}
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/* Check for trailing stuff. */
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if (i == num_devices && strlen(curr_buf) > 0) {
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rc = -EINVAL;
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goto error;
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}
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dev_set_name(&gdev->dev, "%s", dev_name(&gdev->cdev[0]->dev));
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rc = device_add(&gdev->dev);
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if (rc)
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goto error;
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get_device(&gdev->dev);
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rc = device_create_file(&gdev->dev, &dev_attr_ungroup);
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if (rc) {
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device_unregister(&gdev->dev);
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goto error;
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}
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rc = __ccwgroup_create_symlinks(gdev);
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if (!rc) {
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mutex_unlock(&gdev->reg_mutex);
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put_device(&gdev->dev);
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return 0;
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}
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device_remove_file(&gdev->dev, &dev_attr_ungroup);
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device_unregister(&gdev->dev);
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error:
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for (i = 0; i < num_devices; i++)
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if (gdev->cdev[i]) {
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if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev)
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dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
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put_device(&gdev->cdev[i]->dev);
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gdev->cdev[i] = NULL;
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}
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mutex_unlock(&gdev->reg_mutex);
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put_device(&gdev->dev);
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return rc;
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}
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EXPORT_SYMBOL(ccwgroup_create_from_string);
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static int ccwgroup_notifier(struct notifier_block *nb, unsigned long action,
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void *data);
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static struct notifier_block ccwgroup_nb = {
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.notifier_call = ccwgroup_notifier
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};
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static int __init init_ccwgroup(void)
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{
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int ret;
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ret = bus_register(&ccwgroup_bus_type);
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if (ret)
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return ret;
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ret = bus_register_notifier(&ccwgroup_bus_type, &ccwgroup_nb);
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if (ret)
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bus_unregister(&ccwgroup_bus_type);
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return ret;
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}
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static void __exit cleanup_ccwgroup(void)
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{
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bus_unregister_notifier(&ccwgroup_bus_type, &ccwgroup_nb);
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bus_unregister(&ccwgroup_bus_type);
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}
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module_init(init_ccwgroup);
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module_exit(cleanup_ccwgroup);
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/************************** driver stuff ******************************/
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static int
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ccwgroup_set_online(struct ccwgroup_device *gdev)
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{
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struct ccwgroup_driver *gdrv;
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int ret;
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if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
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return -EAGAIN;
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if (gdev->state == CCWGROUP_ONLINE) {
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ret = 0;
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goto out;
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}
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if (!gdev->dev.driver) {
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ret = -EINVAL;
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goto out;
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}
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gdrv = to_ccwgroupdrv (gdev->dev.driver);
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if ((ret = gdrv->set_online ? gdrv->set_online(gdev) : 0))
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goto out;
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gdev->state = CCWGROUP_ONLINE;
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out:
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atomic_set(&gdev->onoff, 0);
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return ret;
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}
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static int
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ccwgroup_set_offline(struct ccwgroup_device *gdev)
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{
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struct ccwgroup_driver *gdrv;
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int ret;
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if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
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return -EAGAIN;
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if (gdev->state == CCWGROUP_OFFLINE) {
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ret = 0;
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goto out;
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}
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if (!gdev->dev.driver) {
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ret = -EINVAL;
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goto out;
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}
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gdrv = to_ccwgroupdrv (gdev->dev.driver);
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if ((ret = gdrv->set_offline ? gdrv->set_offline(gdev) : 0))
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goto out;
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gdev->state = CCWGROUP_OFFLINE;
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out:
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atomic_set(&gdev->onoff, 0);
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return ret;
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}
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static ssize_t
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ccwgroup_online_store (struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
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{
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struct ccwgroup_device *gdev;
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struct ccwgroup_driver *gdrv;
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unsigned long value;
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int ret;
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if (!dev->driver)
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return -ENODEV;
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gdev = to_ccwgroupdev(dev);
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gdrv = to_ccwgroupdrv(dev->driver);
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if (!try_module_get(gdrv->owner))
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return -EINVAL;
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ret = strict_strtoul(buf, 0, &value);
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if (ret)
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goto out;
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if (value == 1)
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ret = ccwgroup_set_online(gdev);
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else if (value == 0)
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ret = ccwgroup_set_offline(gdev);
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else
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ret = -EINVAL;
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out:
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module_put(gdrv->owner);
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return (ret == 0) ? count : ret;
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}
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static ssize_t
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ccwgroup_online_show (struct device *dev, struct device_attribute *attr, char *buf)
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{
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int online;
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online = (to_ccwgroupdev(dev)->state == CCWGROUP_ONLINE);
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return sprintf(buf, online ? "1\n" : "0\n");
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}
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static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store);
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static int
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ccwgroup_probe (struct device *dev)
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{
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struct ccwgroup_device *gdev;
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struct ccwgroup_driver *gdrv;
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int ret;
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gdev = to_ccwgroupdev(dev);
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gdrv = to_ccwgroupdrv(dev->driver);
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if ((ret = device_create_file(dev, &dev_attr_online)))
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return ret;
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ret = gdrv->probe ? gdrv->probe(gdev) : -ENODEV;
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if (ret)
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device_remove_file(dev, &dev_attr_online);
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return ret;
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}
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static int
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ccwgroup_remove (struct device *dev)
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{
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struct ccwgroup_device *gdev;
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struct ccwgroup_driver *gdrv;
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device_remove_file(dev, &dev_attr_online);
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device_remove_file(dev, &dev_attr_ungroup);
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if (!dev->driver)
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return 0;
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gdev = to_ccwgroupdev(dev);
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gdrv = to_ccwgroupdrv(dev->driver);
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if (gdrv->remove)
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gdrv->remove(gdev);
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return 0;
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}
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static void ccwgroup_shutdown(struct device *dev)
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{
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struct ccwgroup_device *gdev;
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struct ccwgroup_driver *gdrv;
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if (!dev->driver)
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return;
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gdev = to_ccwgroupdev(dev);
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gdrv = to_ccwgroupdrv(dev->driver);
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if (gdrv->shutdown)
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gdrv->shutdown(gdev);
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}
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static int ccwgroup_pm_prepare(struct device *dev)
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{
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struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
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struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
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/* Fail while device is being set online/offline. */
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if (atomic_read(&gdev->onoff))
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return -EAGAIN;
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if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
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return 0;
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return gdrv->prepare ? gdrv->prepare(gdev) : 0;
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}
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static void ccwgroup_pm_complete(struct device *dev)
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{
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struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
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struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
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if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
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return;
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if (gdrv->complete)
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gdrv->complete(gdev);
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}
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static int ccwgroup_pm_freeze(struct device *dev)
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{
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struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
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struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
|
|
|
|
if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
|
|
return 0;
|
|
|
|
return gdrv->freeze ? gdrv->freeze(gdev) : 0;
|
|
}
|
|
|
|
static int ccwgroup_pm_thaw(struct device *dev)
|
|
{
|
|
struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
|
|
struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
|
|
|
|
if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
|
|
return 0;
|
|
|
|
return gdrv->thaw ? gdrv->thaw(gdev) : 0;
|
|
}
|
|
|
|
static int ccwgroup_pm_restore(struct device *dev)
|
|
{
|
|
struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
|
|
struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
|
|
|
|
if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
|
|
return 0;
|
|
|
|
return gdrv->restore ? gdrv->restore(gdev) : 0;
|
|
}
|
|
|
|
static struct dev_pm_ops ccwgroup_pm_ops = {
|
|
.prepare = ccwgroup_pm_prepare,
|
|
.complete = ccwgroup_pm_complete,
|
|
.freeze = ccwgroup_pm_freeze,
|
|
.thaw = ccwgroup_pm_thaw,
|
|
.restore = ccwgroup_pm_restore,
|
|
};
|
|
|
|
static struct bus_type ccwgroup_bus_type = {
|
|
.name = "ccwgroup",
|
|
.match = ccwgroup_bus_match,
|
|
.uevent = ccwgroup_uevent,
|
|
.probe = ccwgroup_probe,
|
|
.remove = ccwgroup_remove,
|
|
.shutdown = ccwgroup_shutdown,
|
|
.pm = &ccwgroup_pm_ops,
|
|
};
|
|
|
|
|
|
static int ccwgroup_notifier(struct notifier_block *nb, unsigned long action,
|
|
void *data)
|
|
{
|
|
struct device *dev = data;
|
|
|
|
if (action == BUS_NOTIFY_UNBIND_DRIVER)
|
|
device_schedule_callback(dev, ccwgroup_ungroup_callback);
|
|
|
|
return NOTIFY_OK;
|
|
}
|
|
|
|
|
|
/**
|
|
* 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;
|
|
cdriver->driver.name = cdriver->name;
|
|
cdriver->driver.owner = cdriver->owner;
|
|
|
|
return driver_register(&cdriver->driver);
|
|
}
|
|
|
|
static int
|
|
__ccwgroup_match_all(struct device *dev, void *data)
|
|
{
|
|
return 1;
|
|
}
|
|
|
|
/**
|
|
* 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. */
|
|
get_driver(&cdriver->driver);
|
|
while ((dev = driver_find_device(&cdriver->driver, NULL, NULL,
|
|
__ccwgroup_match_all))) {
|
|
struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
|
|
|
|
mutex_lock(&gdev->reg_mutex);
|
|
__ccwgroup_remove_symlinks(gdev);
|
|
device_unregister(dev);
|
|
mutex_unlock(&gdev->reg_mutex);
|
|
put_device(dev);
|
|
}
|
|
put_driver(&cdriver->driver);
|
|
driver_unregister(&cdriver->driver);
|
|
}
|
|
|
|
/**
|
|
* 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;
|
|
}
|
|
|
|
static struct ccwgroup_device *
|
|
__ccwgroup_get_gdev_by_cdev(struct ccw_device *cdev)
|
|
{
|
|
struct ccwgroup_device *gdev;
|
|
|
|
gdev = dev_get_drvdata(&cdev->dev);
|
|
if (gdev) {
|
|
if (get_device(&gdev->dev)) {
|
|
mutex_lock(&gdev->reg_mutex);
|
|
if (device_is_registered(&gdev->dev))
|
|
return gdev;
|
|
mutex_unlock(&gdev->reg_mutex);
|
|
put_device(&gdev->dev);
|
|
}
|
|
return NULL;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* 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. */
|
|
gdev = __ccwgroup_get_gdev_by_cdev(cdev);
|
|
if (gdev) {
|
|
__ccwgroup_remove_symlinks(gdev);
|
|
device_unregister(&gdev->dev);
|
|
mutex_unlock(&gdev->reg_mutex);
|
|
put_device(&gdev->dev);
|
|
}
|
|
}
|
|
|
|
MODULE_LICENSE("GPL");
|
|
EXPORT_SYMBOL(ccwgroup_driver_register);
|
|
EXPORT_SYMBOL(ccwgroup_driver_unregister);
|
|
EXPORT_SYMBOL(ccwgroup_probe_ccwdev);
|
|
EXPORT_SYMBOL(ccwgroup_remove_ccwdev);
|