// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Linux/SPARC PROM Configuration Driver
 * Copyright (C) 1996 Thomas K. Dyas (tdyas@noc.rutgers.edu)
 * Copyright (C) 1996 Eddie C. Dost  (ecd@skynet.be)
 *
 * 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.
 */


#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 <linux/uaccess.h>
#include <asm/openpromio.h>
#ifdef CONFIG_PCI
#include <linux/pci.h>
#endif

MODULE_AUTHOR("Thomas K. Dyas <tdyas@noc.rutgers.edu> and Eddie C. Dost <ecd@skynet.be>");
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_domain_bus_and_slot(0,
                                                ((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 char * copyin_string(char __user *user, size_t len)
{
        if ((ssize_t)len < 0 || (ssize_t)(len + 1) < 0)
                return ERR_PTR(-EINVAL);

        return memdup_user_nul(user, len);
}

/*
 *      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);

        str = copyin_string(op.op_name, op.op_namelen);
        if (IS_ERR(str))
                return PTR_ERR(str);

        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 len;

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

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

        str = copyin_string(op.op_name, op.op_namelen);
        if (IS_ERR(str))
                return PTR_ERR(str);

        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;

        str = copyin_string(op.op_name, op.op_namelen);
        if (IS_ERR(str))
                return PTR_ERR(str);

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

        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_obj(DATA);
        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,
        .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)
{
        int err;

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

        options_node = of_get_child_by_name(of_find_node_by_path("/"), "options");
        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);