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    Subject[PATCH] add sysfs misc device support [3/4]
    This adds /sys/class/mem which enables all misc char devices to show up
    properly in udev.

    Note, the misc_init() call has been moved to a subsys_initcall as it
    seems there are a lot of platform specific misc devices that are calling
    misc_register before misc_init() is called.

    Has been posted to lkml a few times in the past and tested by a wide
    range of people.


    diff -Nru a/drivers/char/misc.c b/drivers/char/misc.c
    --- a/drivers/char/misc.c Mon Dec 22 15:56:26 2003
    +++ b/drivers/char/misc.c Mon Dec 22 15:56:26 2003
    @@ -47,7 +47,7 @@
    #include <linux/devfs_fs_kernel.h>
    #include <linux/stat.h>
    #include <linux/init.h>
    -
    +#include <linux/device.h>
    #include <linux/tty.h>
    #include <linux/kmod.h>

    @@ -180,6 +180,91 @@
    return err;
    }

    +/* Misc class implementation */
    +
    +/*
    + * TODO for 2.7:
    + * - add a struct class_device to struct miscdevice and make all usages of
    + * them dynamic. This will let us get rid of struct misc_dev below.
    + */
    +struct misc_dev {
    + struct list_head node;
    + dev_t dev;
    + struct class_device class_dev;
    +};
    +#define to_misc_dev(d) container_of(d, struct misc_dev, class_dev)
    +
    +static LIST_HEAD(misc_dev_list);
    +static spinlock_t misc_dev_list_lock = SPIN_LOCK_UNLOCKED;
    +
    +static void release_misc_dev(struct class_device *class_dev)
    +{
    + struct misc_dev *misc_dev = to_misc_dev(class_dev);
    + kfree(misc_dev);
    +}
    +
    +static struct class misc_class = {
    + .name = "misc",
    + .release = &release_misc_dev,
    +};
    +
    +static ssize_t show_dev(struct class_device *class_dev, char *buf)
    +{
    + struct misc_dev *misc_dev = to_misc_dev(class_dev);
    + return print_dev_t(buf, misc_dev->dev);
    +}
    +static CLASS_DEVICE_ATTR(dev, S_IRUGO, show_dev, NULL);
    +
    +static void misc_add_class_device(struct miscdevice *misc)
    +{
    + struct misc_dev *misc_dev = NULL;
    + int retval;
    +
    + misc_dev = kmalloc(sizeof(*misc_dev), GFP_KERNEL);
    + if (!misc_dev)
    + return;
    + memset(misc_dev, 0x00, sizeof(*misc_dev));
    +
    + misc_dev->dev = MKDEV(MISC_MAJOR, misc->minor);
    + misc_dev->class_dev.dev = misc->dev;
    + misc_dev->class_dev.class = &misc_class;
    + snprintf(misc_dev->class_dev.class_id, BUS_ID_SIZE, "%s", misc->name);
    + retval = class_device_register(&misc_dev->class_dev);
    + if (retval)
    + goto error;
    + class_device_create_file(&misc_dev->class_dev, &class_device_attr_dev);
    + spin_lock(&misc_dev_list_lock);
    + list_add(&misc_dev->node, &misc_dev_list);
    + spin_unlock(&misc_dev_list_lock);
    + return;
    +error:
    + kfree(misc_dev);
    +}
    +
    +static void misc_remove_class_device(struct miscdevice *misc)
    +{
    + struct misc_dev *misc_dev = NULL;
    + struct list_head *tmp;
    + int found = 0;
    +
    + spin_lock(&misc_dev_list_lock);
    + list_for_each(tmp, &misc_dev_list) {
    + misc_dev = list_entry(tmp, struct misc_dev, node);
    + if ((MINOR(misc_dev->dev) == misc->minor)) {
    + found = 1;
    + break;
    + }
    + }
    + if (found) {
    + list_del(&misc_dev->node);
    + spin_unlock(&misc_dev_list_lock);
    + class_device_unregister(&misc_dev->class_dev);
    + } else {
    + spin_unlock(&misc_dev_list_lock);
    + }
    +}
    +
    +
    static struct file_operations misc_fops = {
    .owner = THIS_MODULE,
    .open = misc_open,
    @@ -236,6 +321,7 @@

    devfs_mk_cdev(MKDEV(MISC_MAJOR, misc->minor),
    S_IFCHR|S_IRUSR|S_IWUSR|S_IRGRP, misc->devfs_name);
    + misc_add_class_device(misc);

    /*
    * Add it to the front, so that later devices can "override"
    @@ -265,6 +351,7 @@

    down(&misc_sem);
    list_del(&misc->list);
    + misc_remove_class_device(misc);
    devfs_remove(misc->devfs_name);
    if (i < DYNAMIC_MINORS && i>0) {
    misc_minors[i>>3] &= ~(1 << (misc->minor & 7));
    @@ -285,6 +372,7 @@
    if (ent)
    ent->proc_fops = &misc_proc_fops;
    #endif
    + class_register(&misc_class);
    #ifdef CONFIG_MVME16x
    rtc_MK48T08_init();
    #endif
    @@ -319,4 +407,4 @@
    }
    return 0;
    }
    -module_init(misc_init);
    +subsys_initcall(misc_init);
    diff -Nru a/include/linux/miscdevice.h b/include/linux/miscdevice.h
    --- a/include/linux/miscdevice.h Mon Dec 22 15:56:22 2003
    +++ b/include/linux/miscdevice.h Mon Dec 22 15:56:22 2003
    @@ -36,12 +36,15 @@

    #define TUN_MINOR 200

    +struct device;
    +
    struct miscdevice
    {
    int minor;
    const char *name;
    struct file_operations *fops;
    struct list_head list;
    + struct device *dev;
    char devfs_name[64];
    };

    -
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