openprom.c

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/*
 * Linux/SPARC PROM Configuration Driver
 * Copyright (C) 1996 Thomas K. Dyas ([email protected])
 * Copyright (C) 1996 Eddie C. Dost  ([email protected])
 *
 * This character device driver allows user programs to access the
 * PROM device tree. It is compatible with the SunOS /dev/openprom
 * driver and the NetBSD /dev/openprom driver. The SunOS eeprom
 * utility works without any modifications.
 *
 * The driver uses a minor number under the misc device major. The
 * file read/write mode determines the type of access to the PROM.
 * Interrupts are disabled whenever the driver calls into the PROM for
 * sanity's sake.
 */

/* This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * 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/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/string.h>
#include <linux/miscdevice.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <asm/oplib.h>
#include <asm/prom.h>
#include <asm/uaccess.h>
#include <asm/openpromio.h>
#ifdef CONFIG_PCI
#include <linux/pci.h>
#endif

MODULE_AUTHOR("Thomas K. Dyas ([email protected]) and Eddie C. Dost  ([email protected])");
MODULE_DESCRIPTION("OPENPROM Configuration Driver");
MODULE_LICENSE("GPL");
MODULE_VERSION("1.0");
MODULE_ALIAS_MISCDEV(SUN_OPENPROM_MINOR);

/* Private data kept by the driver for each descriptor. */
typedef struct openprom_private_data
{
    struct device_node *current_node; /* Current node for SunOS ioctls. */
    struct device_node *lastnode; /* Last valid node used by BSD ioctls. */
} DATA;

/* ID of the PROM node containing all of the EEPROM options. */
static DEFINE_MUTEX(openprom_mutex);
static struct device_node *options_node;

/*
 * Copy an openpromio structure into kernel space from user space.
 * This routine does error checking to make sure that all memory
 * accesses are within bounds. A pointer to the allocated openpromio
 * structure will be placed in "*opp_p". Return value is the length
 * of the user supplied buffer.
 */
static int copyin(struct openpromio __user *info, struct openpromio **opp_p)
{
    unsigned int bufsize;

    if (!info || !opp_p)
        return -EFAULT;

    if (get_user(bufsize, &info->oprom_size))
        return -EFAULT;

    if (bufsize == 0)
        return -EINVAL;

    /* If the bufsize is too large, just limit it.
     * Fix from Jason Rappleye.
     */
    if (bufsize > OPROMMAXPARAM)
        bufsize = OPROMMAXPARAM;

    if (!(*opp_p = kzalloc(sizeof(int) + bufsize + 1, GFP_KERNEL)))
        return -ENOMEM;

    if (copy_from_user(&(*opp_p)->oprom_array,
               &info->oprom_array, bufsize)) {
        kfree(*opp_p);
        return -EFAULT;
    }
    return bufsize;
}

static int getstrings(struct openpromio __user *info, struct openpromio **opp_p)
{
    int n, bufsize;
    char c;

    if (!info || !opp_p)
        return -EFAULT;

    if (!(*opp_p = kzalloc(sizeof(int) + OPROMMAXPARAM + 1, GFP_KERNEL)))
        return -ENOMEM;

    (*opp_p)->oprom_size = 0;

    n = bufsize = 0;
    while ((n < 2) && (bufsize < OPROMMAXPARAM)) {
        if (get_user(c, &info->oprom_array[bufsize])) {
            kfree(*opp_p);
            return -EFAULT;
        }
        if (c == '\0')
            n++;
        (*opp_p)->oprom_array[bufsize++] = c;
    }
    if (!n) {
        kfree(*opp_p);
        return -EINVAL;
    }
    return bufsize;
}

/*
 * Copy an openpromio structure in kernel space back to user space.
 */
static int copyout(void __user *info, struct openpromio *opp, int len)
{
    if (copy_to_user(info, opp, len))
        return -EFAULT;
    return 0;
}

static int opromgetprop(void __user *argp, struct device_node *dp, struct openpromio *op, int bufsize)
{
    const void *pval;
    int len;

    if (!dp ||
        !(pval = of_get_property(dp, op->oprom_array, &len)) ||
        len <= 0 || len > bufsize)
        return copyout(argp, op, sizeof(int));

    memcpy(op->oprom_array, pval, len);
    op->oprom_array[len] = '\0';
    op->oprom_size = len;

    return copyout(argp, op, sizeof(int) + bufsize);
}

static int opromnxtprop(void __user *argp, struct device_node *dp, struct openpromio *op, int bufsize)
{
    struct property *prop;
    int len;

    if (!dp)
        return copyout(argp, op, sizeof(int));
    if (op->oprom_array[0] == '\0') {
        prop = dp->properties;
        if (!prop)
            return copyout(argp, op, sizeof(int));
        len = strlen(prop->name);
    } else {
        prop = of_find_property(dp, op->oprom_array, NULL);

        if (!prop ||
            !prop->next ||
            (len = strlen(prop->next->name)) + 1 > bufsize)
            return copyout(argp, op, sizeof(int));

        prop = prop->next;
    }

    memcpy(op->oprom_array, prop->name, len);
    op->oprom_array[len] = '\0';
    op->oprom_size = ++len;

    return copyout(argp, op, sizeof(int) + bufsize);
}

static int opromsetopt(struct device_node *dp, struct openpromio *op, int bufsize)
{
    char *buf = op->oprom_array + strlen(op->oprom_array) + 1;
    int len = op->oprom_array + bufsize - buf;

    return of_set_property(options_node, op->oprom_array, buf, len);
}

static int opromnext(void __user *argp, unsigned int cmd, struct device_node *dp, struct openpromio *op, int bufsize, DATA *data)
{
    phandle ph;

    BUILD_BUG_ON(sizeof(phandle) != sizeof(int));

    if (bufsize < sizeof(phandle))
        return -EINVAL;

    ph = *((int *) op->oprom_array);
    if (ph) {
        dp = of_find_node_by_phandle(ph);
        if (!dp)
            return -EINVAL;

        switch (cmd) {
        case OPROMNEXT:
            dp = dp->sibling;
            break;

        case OPROMCHILD:
            dp = dp->child;
            break;

        case OPROMSETCUR:
        default:
            break;
        }
    } else {
        /* Sibling of node zero is the root node.  */
        if (cmd != OPROMNEXT)
            return -EINVAL;

        dp = of_find_node_by_path("/");
    }

    ph = 0;
    if (dp)
        ph = dp->phandle;

    data->current_node = dp;
    *((int *) op->oprom_array) = ph;
    op->oprom_size = sizeof(phandle);

    return copyout(argp, op, bufsize + sizeof(int));
}

static int oprompci2node(void __user *argp, struct device_node *dp, struct openpromio *op, int bufsize, DATA *data)
{
    int err = -EINVAL;

    if (bufsize >= 2*sizeof(int)) {
#ifdef CONFIG_PCI
        struct pci_dev *pdev;
        struct device_node *dp;

        pdev = pci_get_bus_and_slot (((int *) op->oprom_array)[0],
                      ((int *) op->oprom_array)[1]);

        dp = pci_device_to_OF_node(pdev);
        data->current_node = dp;
        *((int *)op->oprom_array) = dp->phandle;
        op->oprom_size = sizeof(int);
        err = copyout(argp, op, bufsize + sizeof(int));

        pci_dev_put(pdev);
#endif
    }

    return err;
}

static int oprompath2node(void __user *argp, struct device_node *dp, struct openpromio *op, int bufsize, DATA *data)
{
    phandle ph = 0;

    dp = of_find_node_by_path(op->oprom_array);
    if (dp)
        ph = dp->phandle;
    data->current_node = dp;
    *((int *)op->oprom_array) = ph;
    op->oprom_size = sizeof(int);

    return copyout(argp, op, bufsize + sizeof(int));
}

static int opromgetbootargs(void __user *argp, struct openpromio *op, int bufsize)
{
    char *buf = saved_command_line;
    int len = strlen(buf);

    if (len > bufsize)
        return -EINVAL;

    strcpy(op->oprom_array, buf);
    op->oprom_size = len;

    return copyout(argp, op, bufsize + sizeof(int));
}

/*
 *  SunOS and Solaris /dev/openprom ioctl calls.
 */
static long openprom_sunos_ioctl(struct file * file,
                 unsigned int cmd, unsigned long arg,
                 struct device_node *dp)
{
    DATA *data = file->private_data;
    struct openpromio *opp = NULL;
    int bufsize, error = 0;
    static int cnt;
    void __user *argp = (void __user *)arg;

    if (cmd == OPROMSETOPT)
        bufsize = getstrings(argp, &opp);
    else
        bufsize = copyin(argp, &opp);

    if (bufsize < 0)
        return bufsize;

    mutex_lock(&openprom_mutex);

    switch (cmd) {
    case OPROMGETOPT:
    case OPROMGETPROP:
        error = opromgetprop(argp, dp, opp, bufsize);
        break;

    case OPROMNXTOPT:
    case OPROMNXTPROP:
        error = opromnxtprop(argp, dp, opp, bufsize);
        break;

    case OPROMSETOPT:
    case OPROMSETOPT2:
        error = opromsetopt(dp, opp, bufsize);
        break;

    case OPROMNEXT:
    case OPROMCHILD:
    case OPROMSETCUR:
        error = opromnext(argp, cmd, dp, opp, bufsize, data);
        break;

    case OPROMPCI2NODE:
        error = oprompci2node(argp, dp, opp, bufsize, data);
        break;

    case OPROMPATH2NODE:
        error = oprompath2node(argp, dp, opp, bufsize, data);
        break;

    case OPROMGETBOOTARGS:
        error = opromgetbootargs(argp, opp, bufsize);
        break;

    case OPROMU2P:
    case OPROMGETCONS:
    case OPROMGETFBNAME:
        if (cnt++ < 10)
            printk(KERN_INFO "openprom_sunos_ioctl: unimplemented ioctl\n");
        error = -EINVAL;
        break;
    default:
        if (cnt++ < 10)
            printk(KERN_INFO "openprom_sunos_ioctl: cmd 0x%X, arg 0x%lX\n", cmd, arg);
        error = -EINVAL;
        break;
    }

    kfree(opp);
    mutex_unlock(&openprom_mutex);

    return error;
}

static struct device_node *get_node(phandle n, DATA *data)
{
    struct device_node *dp = of_find_node_by_phandle(n);

    if (dp)
        data->lastnode = dp;

    return dp;
}

/* Copy in a whole string from userspace into kernelspace. */
static int copyin_string(char __user *user, size_t len, char **ptr)
{
    char *tmp;

    if ((ssize_t)len < 0 || (ssize_t)(len + 1) < 0)
        return -EINVAL;

    tmp = kmalloc(len + 1, GFP_KERNEL);
    if (!tmp)
        return -ENOMEM;

    if (copy_from_user(tmp, user, len)) {
        kfree(tmp);
        return -EFAULT;
    }

    tmp[len] = '\0';

    *ptr = tmp;

    return 0;
}

/*
 *  NetBSD /dev/openprom ioctl calls.
 */
static int opiocget(void __user *argp, DATA *data)
{
    struct opiocdesc op;
    struct device_node *dp;
    char *str;
    const void *pval;
    int err, len;

    if (copy_from_user(&op, argp, sizeof(op)))
        return -EFAULT;

    dp = get_node(op.op_nodeid, data);

    err = copyin_string(op.op_name, op.op_namelen, &str);
    if (err)
        return err;

    pval = of_get_property(dp, str, &len);
    err = 0;
    if (!pval || len > op.op_buflen) {
        err = -EINVAL;
    } else {
        op.op_buflen = len;
        if (copy_to_user(argp, &op, sizeof(op)) ||
            copy_to_user(op.op_buf, pval, len))
            err = -EFAULT;
    }
    kfree(str);

    return err;
}

static int opiocnextprop(void __user *argp, DATA *data)
{
    struct opiocdesc op;
    struct device_node *dp;
    struct property *prop;
    char *str;
    int err, len;

    if (copy_from_user(&op, argp, sizeof(op)))
        return -EFAULT;

    dp = get_node(op.op_nodeid, data);
    if (!dp)
        return -EINVAL;

    err = copyin_string(op.op_name, op.op_namelen, &str);
    if (err)
        return err;

    if (str[0] == '\0') {
        prop = dp->properties;
    } else {
        prop = of_find_property(dp, str, NULL);
        if (prop)
            prop = prop->next;
    }
    kfree(str);

    if (!prop)
        len = 0;
    else
        len = prop->length;

    if (len > op.op_buflen)
        len = op.op_buflen;

    if (copy_to_user(argp, &op, sizeof(op)))
        return -EFAULT;

    if (len &&
        copy_to_user(op.op_buf, prop->value, len))
        return -EFAULT;

    return 0;
}

static int opiocset(void __user *argp, DATA *data)
{
    struct opiocdesc op;
    struct device_node *dp;
    char *str, *tmp;
    int err;

    if (copy_from_user(&op, argp, sizeof(op)))
        return -EFAULT;

    dp = get_node(op.op_nodeid, data);
    if (!dp)
        return -EINVAL;

    err = copyin_string(op.op_name, op.op_namelen, &str);
    if (err)
        return err;

    err = copyin_string(op.op_buf, op.op_buflen, &tmp);
    if (err) {
        kfree(str);
        return err;
    }

    err = of_set_property(dp, str, tmp, op.op_buflen);

    kfree(str);
    kfree(tmp);

    return err;
}

static int opiocgetnext(unsigned int cmd, void __user *argp)
{
    struct device_node *dp;
    phandle nd;

    BUILD_BUG_ON(sizeof(phandle) != sizeof(int));

    if (copy_from_user(&nd, argp, sizeof(phandle)))
        return -EFAULT;

    if (nd == 0) {
        if (cmd != OPIOCGETNEXT)
            return -EINVAL;
        dp = of_find_node_by_path("/");
    } else {
        dp = of_find_node_by_phandle(nd);
        nd = 0;
        if (dp) {
            if (cmd == OPIOCGETNEXT)
                dp = dp->sibling;
            else
                dp = dp->child;
        }
    }
    if (dp)
        nd = dp->phandle;
    if (copy_to_user(argp, &nd, sizeof(phandle)))
        return -EFAULT;

    return 0;
}

static int openprom_bsd_ioctl(struct file * file,
                  unsigned int cmd, unsigned long arg)
{
    DATA *data = file->private_data;
    void __user *argp = (void __user *)arg;
    int err;

    mutex_lock(&openprom_mutex);
    switch (cmd) {
    case OPIOCGET:
        err = opiocget(argp, data);
        break;

    case OPIOCNEXTPROP:
        err = opiocnextprop(argp, data);
        break;

    case OPIOCSET:
        err = opiocset(argp, data);
        break;

    case OPIOCGETOPTNODE:
        BUILD_BUG_ON(sizeof(phandle) != sizeof(int));

        err = 0;
        if (copy_to_user(argp, &options_node->phandle, sizeof(phandle)))
            err = -EFAULT;
        break;

    case OPIOCGETNEXT:
    case OPIOCGETCHILD:
        err = opiocgetnext(cmd, argp);
        break;

    default:
        err = -EINVAL;
        break;
    }
    mutex_unlock(&openprom_mutex);

    return err;
}


/*
 *  Handoff control to the correct ioctl handler.
 */
static long openprom_ioctl(struct file * file,
               unsigned int cmd, unsigned long arg)
{
    DATA *data = file->private_data;

    switch (cmd) {
    case OPROMGETOPT:
    case OPROMNXTOPT:
        if ((file->f_mode & FMODE_READ) == 0)
            return -EPERM;
        return openprom_sunos_ioctl(file, cmd, arg,
                        options_node);

    case OPROMSETOPT:
    case OPROMSETOPT2:
        if ((file->f_mode & FMODE_WRITE) == 0)
            return -EPERM;
        return openprom_sunos_ioctl(file, cmd, arg,
                        options_node);

    case OPROMNEXT:
    case OPROMCHILD:
    case OPROMGETPROP:
    case OPROMNXTPROP:
        if ((file->f_mode & FMODE_READ) == 0)
            return -EPERM;
        return openprom_sunos_ioctl(file, cmd, arg,
                        data->current_node);

    case OPROMU2P:
    case OPROMGETCONS:
    case OPROMGETFBNAME:
    case OPROMGETBOOTARGS:
    case OPROMSETCUR:
    case OPROMPCI2NODE:
    case OPROMPATH2NODE:
        if ((file->f_mode & FMODE_READ) == 0)
            return -EPERM;
        return openprom_sunos_ioctl(file, cmd, arg, NULL);

    case OPIOCGET:
    case OPIOCNEXTPROP:
    case OPIOCGETOPTNODE:
    case OPIOCGETNEXT:
    case OPIOCGETCHILD:
        if ((file->f_mode & FMODE_READ) == 0)
            return -EBADF;
        return openprom_bsd_ioctl(file,cmd,arg);

    case OPIOCSET:
        if ((file->f_mode & FMODE_WRITE) == 0)
            return -EBADF;
        return openprom_bsd_ioctl(file,cmd,arg);

    default:
        return -EINVAL;
    };
}

static long openprom_compat_ioctl(struct file *file, unsigned int cmd,
        unsigned long arg)
{
    long rval = -ENOTTY;

    /*
     * SunOS/Solaris only, the NetBSD one's have embedded pointers in
     * the arg which we'd need to clean up...
     */
    switch (cmd) {
    case OPROMGETOPT:
    case OPROMSETOPT:
    case OPROMNXTOPT:
    case OPROMSETOPT2:
    case OPROMNEXT:
    case OPROMCHILD:
    case OPROMGETPROP:
    case OPROMNXTPROP:
    case OPROMU2P:
    case OPROMGETCONS:
    case OPROMGETFBNAME:
    case OPROMGETBOOTARGS:
    case OPROMSETCUR:
    case OPROMPCI2NODE:
    case OPROMPATH2NODE:
        rval = openprom_ioctl(file, cmd, arg);
        break;
    }

    return rval;
}

static int openprom_open(struct inode * inode, struct file * file)
{
    DATA *data;

    data = kmalloc(sizeof(DATA), GFP_KERNEL);
    if (!data)
        return -ENOMEM;

    mutex_lock(&openprom_mutex);
    data->current_node = of_find_node_by_path("/");
    data->lastnode = data->current_node;
    file->private_data = (void *) data;
    mutex_unlock(&openprom_mutex);

    return 0;
}

static int openprom_release(struct inode * inode, struct file * file)
{
    kfree(file->private_data);
    return 0;
}

static const struct file_operations openprom_fops = {
    .owner =    THIS_MODULE,
    .llseek =   no_llseek,
    .unlocked_ioctl = openprom_ioctl,
    .compat_ioctl = openprom_compat_ioctl,
    .open =     openprom_open,
    .release =  openprom_release,
};

static struct miscdevice openprom_dev = {
    .minor      = SUN_OPENPROM_MINOR,
    .name       = "openprom",
    .fops       = &openprom_fops,
};

static int __init openprom_init(void)
{
    struct device_node *dp;
    int err;

    err = misc_register(&openprom_dev);
    if (err)
        return err;

    dp = of_find_node_by_path("/");
    dp = dp->child;
    while (dp) {
        if (!strcmp(dp->name, "options"))
            break;
        dp = dp->sibling;
    }
    options_node = dp;

    if (!options_node) {
        misc_deregister(&openprom_dev);
        return -EIO;
    }

    return 0;
}

static void __exit openprom_cleanup(void)
{
    misc_deregister(&openprom_dev);
}

module_init(openprom_init);
module_exit(openprom_cleanup);