enclosure.c

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/*
 * Enclosure Services
 *
 * Copyright (C) 2008 James Bottomley <[email protected]>
 *
**-----------------------------------------------------------------------------
**
**  This program is free software; you can redistribute it and/or
**  modify it under the terms of the GNU General Public License
**  version 2 as published by the Free Software Foundation.
**
**  This program is distributed in the hope that it will be useful,
**  but WITHOUT ANY WARRANTY; without even the implied warranty of
**  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
**  GNU General Public License for more details.
**
**  You should have received a copy of the GNU General Public License
**  along with this program; if not, write to the Free Software
**  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
**
**-----------------------------------------------------------------------------
*/
#include <linux/device.h>
#include <linux/enclosure.h>
#include <linux/err.h>
#include <linux/list.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/slab.h>

static LIST_HEAD(container_list);
static DEFINE_MUTEX(container_list_lock);
static struct class enclosure_class;

struct enclosure_device *enclosure_find(struct device *dev,
                    struct enclosure_device *start)
{
    struct enclosure_device *edev;

    mutex_lock(&container_list_lock);
    edev = list_prepare_entry(start, &container_list, node);
    if (start)
        put_device(&start->edev);

    list_for_each_entry_continue(edev, &container_list, node) {
        struct device *parent = edev->edev.parent;
        /* parent might not be immediate, so iterate up to
         * the root of the tree if necessary */
        while (parent) {
            if (parent == dev) {
                get_device(&edev->edev);
                mutex_unlock(&container_list_lock);
                return edev;
            }
            parent = parent->parent;
        }
    }
    mutex_unlock(&container_list_lock);

    return NULL;
}
EXPORT_SYMBOL_GPL(enclosure_find);

int enclosure_for_each_device(int (*fn)(struct enclosure_device *, void *),
                  void *data)
{
    int error = 0;
    struct enclosure_device *edev;

    mutex_lock(&container_list_lock);
    list_for_each_entry(edev, &container_list, node) {
        error = fn(edev, data);
        if (error)
            break;
    }
    mutex_unlock(&container_list_lock);

    return error;
}
EXPORT_SYMBOL_GPL(enclosure_for_each_device);

struct enclosure_device *
enclosure_register(struct device *dev, const char *name, int components,
           struct enclosure_component_callbacks *cb)
{
    struct enclosure_device *edev =
        kzalloc(sizeof(struct enclosure_device) +
            sizeof(struct enclosure_component)*components,
            GFP_KERNEL);
    int err, i;

    BUG_ON(!cb);

    if (!edev)
        return ERR_PTR(-ENOMEM);

    edev->components = components;

    edev->edev.class = &enclosure_class;
    edev->edev.parent = get_device(dev);
    edev->cb = cb;
    dev_set_name(&edev->edev, "%s", name);
    err = device_register(&edev->edev);
    if (err)
        goto err;

    for (i = 0; i < components; i++)
        edev->component[i].number = -1;

    mutex_lock(&container_list_lock);
    list_add_tail(&edev->node, &container_list);
    mutex_unlock(&container_list_lock);

    return edev;

 err:
    put_device(edev->edev.parent);
    kfree(edev);
    return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(enclosure_register);

static struct enclosure_component_callbacks enclosure_null_callbacks;

void enclosure_unregister(struct enclosure_device *edev)
{
    int i;

    mutex_lock(&container_list_lock);
    list_del(&edev->node);
    mutex_unlock(&container_list_lock);

    for (i = 0; i < edev->components; i++)
        if (edev->component[i].number != -1)
            device_unregister(&edev->component[i].cdev);

    /* prevent any callbacks into service user */
    edev->cb = &enclosure_null_callbacks;
    device_unregister(&edev->edev);
}
EXPORT_SYMBOL_GPL(enclosure_unregister);

#define ENCLOSURE_NAME_SIZE 64

static void enclosure_link_name(struct enclosure_component *cdev, char *name)
{
    strcpy(name, "enclosure_device:");
    strcat(name, dev_name(&cdev->cdev));
}

static void enclosure_remove_links(struct enclosure_component *cdev)
{
    char name[ENCLOSURE_NAME_SIZE];

    enclosure_link_name(cdev, name);
    sysfs_remove_link(&cdev->dev->kobj, name);
    sysfs_remove_link(&cdev->cdev.kobj, "device");
}

static int enclosure_add_links(struct enclosure_component *cdev)
{
    int error;
    char name[ENCLOSURE_NAME_SIZE];

    error = sysfs_create_link(&cdev->cdev.kobj, &cdev->dev->kobj, "device");
    if (error)
        return error;

    enclosure_link_name(cdev, name);
    error = sysfs_create_link(&cdev->dev->kobj, &cdev->cdev.kobj, name);
    if (error)
        sysfs_remove_link(&cdev->cdev.kobj, "device");

    return error;
}

static void enclosure_release(struct device *cdev)
{
    struct enclosure_device *edev = to_enclosure_device(cdev);

    put_device(cdev->parent);
    kfree(edev);
}

static void enclosure_component_release(struct device *dev)
{
    struct enclosure_component *cdev = to_enclosure_component(dev);

    if (cdev->dev) {
        enclosure_remove_links(cdev);
        put_device(cdev->dev);
    }
    put_device(dev->parent);
}

static const struct attribute_group *enclosure_groups[];

struct enclosure_component *
enclosure_component_register(struct enclosure_device *edev,
                 unsigned int number,
                 enum enclosure_component_type type,
                 const char *name)
{
    struct enclosure_component *ecomp;
    struct device *cdev;
    int err;

    if (number >= edev->components)
        return ERR_PTR(-EINVAL);

    ecomp = &edev->component[number];

    if (ecomp->number != -1)
        return ERR_PTR(-EINVAL);

    ecomp->type = type;
    ecomp->number = number;
    cdev = &ecomp->cdev;
    cdev->parent = get_device(&edev->edev);
    if (name && name[0])
        dev_set_name(cdev, "%s", name);
    else
        dev_set_name(cdev, "%u", number);

    cdev->release = enclosure_component_release;
    cdev->groups = enclosure_groups;

    err = device_register(cdev);
    if (err) {
        ecomp->number = -1;
        put_device(cdev);
        return ERR_PTR(err);
    }

    return ecomp;
}
EXPORT_SYMBOL_GPL(enclosure_component_register);

int enclosure_add_device(struct enclosure_device *edev, int component,
             struct device *dev)
{
    struct enclosure_component *cdev;

    if (!edev || component >= edev->components)
        return -EINVAL;

    cdev = &edev->component[component];

    if (cdev->dev == dev)
        return -EEXIST;

    if (cdev->dev)
        enclosure_remove_links(cdev);

    put_device(cdev->dev);
    cdev->dev = get_device(dev);
    return enclosure_add_links(cdev);
}
EXPORT_SYMBOL_GPL(enclosure_add_device);

int enclosure_remove_device(struct enclosure_device *edev, struct device *dev)
{
    struct enclosure_component *cdev;
    int i;

    if (!edev || !dev)
        return -EINVAL;

    for (i = 0; i < edev->components; i++) {
        cdev = &edev->component[i];
        if (cdev->dev == dev) {
            enclosure_remove_links(cdev);
            device_del(&cdev->cdev);
            put_device(dev);
            cdev->dev = NULL;
            return device_add(&cdev->cdev);
        }
    }
    return -ENODEV;
}
EXPORT_SYMBOL_GPL(enclosure_remove_device);

/*
 * sysfs pieces below
 */

static ssize_t enclosure_show_components(struct device *cdev,
                     struct device_attribute *attr,
                     char *buf)
{
    struct enclosure_device *edev = to_enclosure_device(cdev);

    return snprintf(buf, 40, "%d\n", edev->components);
}

static struct device_attribute enclosure_attrs[] = {
    __ATTR(components, S_IRUGO, enclosure_show_components, NULL),
    __ATTR_NULL
};

static struct class enclosure_class = {
    .name           = "enclosure",
    .owner          = THIS_MODULE,
    .dev_release        = enclosure_release,
    .dev_attrs      = enclosure_attrs,
};

static const char *const enclosure_status [] = {
    [ENCLOSURE_STATUS_UNSUPPORTED] = "unsupported",
    [ENCLOSURE_STATUS_OK] = "OK",
    [ENCLOSURE_STATUS_CRITICAL] = "critical",
    [ENCLOSURE_STATUS_NON_CRITICAL] = "non-critical",
    [ENCLOSURE_STATUS_UNRECOVERABLE] = "unrecoverable",
    [ENCLOSURE_STATUS_NOT_INSTALLED] = "not installed",
    [ENCLOSURE_STATUS_UNKNOWN] = "unknown",
    [ENCLOSURE_STATUS_UNAVAILABLE] = "unavailable",
    [ENCLOSURE_STATUS_MAX] = NULL,
};

static const char *const enclosure_type [] = {
    [ENCLOSURE_COMPONENT_DEVICE] = "device",
    [ENCLOSURE_COMPONENT_ARRAY_DEVICE] = "array device",
};

static ssize_t get_component_fault(struct device *cdev,
                   struct device_attribute *attr, char *buf)
{
    struct enclosure_device *edev = to_enclosure_device(cdev->parent);
    struct enclosure_component *ecomp = to_enclosure_component(cdev);

    if (edev->cb->get_fault)
        edev->cb->get_fault(edev, ecomp);
    return snprintf(buf, 40, "%d\n", ecomp->fault);
}

static ssize_t set_component_fault(struct device *cdev,
                   struct device_attribute *attr,
                   const char *buf, size_t count)
{
    struct enclosure_device *edev = to_enclosure_device(cdev->parent);
    struct enclosure_component *ecomp = to_enclosure_component(cdev);
    int val = simple_strtoul(buf, NULL, 0);

    if (edev->cb->set_fault)
        edev->cb->set_fault(edev, ecomp, val);
    return count;
}

static ssize_t get_component_status(struct device *cdev,
                    struct device_attribute *attr,char *buf)
{
    struct enclosure_device *edev = to_enclosure_device(cdev->parent);
    struct enclosure_component *ecomp = to_enclosure_component(cdev);

    if (edev->cb->get_status)
        edev->cb->get_status(edev, ecomp);
    return snprintf(buf, 40, "%s\n", enclosure_status[ecomp->status]);
}

static ssize_t set_component_status(struct device *cdev,
                    struct device_attribute *attr,
                    const char *buf, size_t count)
{
    struct enclosure_device *edev = to_enclosure_device(cdev->parent);
    struct enclosure_component *ecomp = to_enclosure_component(cdev);
    int i;

    for (i = 0; enclosure_status[i]; i++) {
        if (strncmp(buf, enclosure_status[i],
                strlen(enclosure_status[i])) == 0 &&
            (buf[strlen(enclosure_status[i])] == '\n' ||
             buf[strlen(enclosure_status[i])] == '\0'))
            break;
    }

    if (enclosure_status[i] && edev->cb->set_status) {
        edev->cb->set_status(edev, ecomp, i);
        return count;
    } else
        return -EINVAL;
}

static ssize_t get_component_active(struct device *cdev,
                    struct device_attribute *attr, char *buf)
{
    struct enclosure_device *edev = to_enclosure_device(cdev->parent);
    struct enclosure_component *ecomp = to_enclosure_component(cdev);

    if (edev->cb->get_active)
        edev->cb->get_active(edev, ecomp);
    return snprintf(buf, 40, "%d\n", ecomp->active);
}

static ssize_t set_component_active(struct device *cdev,
                    struct device_attribute *attr,
                    const char *buf, size_t count)
{
    struct enclosure_device *edev = to_enclosure_device(cdev->parent);
    struct enclosure_component *ecomp = to_enclosure_component(cdev);
    int val = simple_strtoul(buf, NULL, 0);

    if (edev->cb->set_active)
        edev->cb->set_active(edev, ecomp, val);
    return count;
}

static ssize_t get_component_locate(struct device *cdev,
                    struct device_attribute *attr, char *buf)
{
    struct enclosure_device *edev = to_enclosure_device(cdev->parent);
    struct enclosure_component *ecomp = to_enclosure_component(cdev);

    if (edev->cb->get_locate)
        edev->cb->get_locate(edev, ecomp);
    return snprintf(buf, 40, "%d\n", ecomp->locate);
}

static ssize_t set_component_locate(struct device *cdev,
                    struct device_attribute *attr,
                    const char *buf, size_t count)
{
    struct enclosure_device *edev = to_enclosure_device(cdev->parent);
    struct enclosure_component *ecomp = to_enclosure_component(cdev);
    int val = simple_strtoul(buf, NULL, 0);

    if (edev->cb->set_locate)
        edev->cb->set_locate(edev, ecomp, val);
    return count;
}

static ssize_t get_component_type(struct device *cdev,
                  struct device_attribute *attr, char *buf)
{
    struct enclosure_component *ecomp = to_enclosure_component(cdev);

    return snprintf(buf, 40, "%s\n", enclosure_type[ecomp->type]);
}


static DEVICE_ATTR(fault, S_IRUGO | S_IWUSR, get_component_fault,
            set_component_fault);
static DEVICE_ATTR(status, S_IRUGO | S_IWUSR, get_component_status,
           set_component_status);
static DEVICE_ATTR(active, S_IRUGO | S_IWUSR, get_component_active,
           set_component_active);
static DEVICE_ATTR(locate, S_IRUGO | S_IWUSR, get_component_locate,
           set_component_locate);
static DEVICE_ATTR(type, S_IRUGO, get_component_type, NULL);

static struct attribute *enclosure_component_attrs[] = {
    &dev_attr_fault.attr,
    &dev_attr_status.attr,
    &dev_attr_active.attr,
    &dev_attr_locate.attr,
    &dev_attr_type.attr,
    NULL
};

static struct attribute_group enclosure_group = {
    .attrs = enclosure_component_attrs,
};

static const struct attribute_group *enclosure_groups[] = {
    &enclosure_group,
    NULL
};

static int __init enclosure_init(void)
{
    int err;

    err = class_register(&enclosure_class);
    if (err)
        return err;

    return 0;
}

static void __exit enclosure_exit(void)
{
    class_unregister(&enclosure_class);
}

module_init(enclosure_init);
module_exit(enclosure_exit);

MODULE_AUTHOR("James Bottomley");
MODULE_DESCRIPTION("Enclosure Services");
MODULE_LICENSE("GPL v2");