reconfig.c

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/*
 * pSeries_reconfig.c - support for dynamic reconfiguration (including PCI
 * Hotplug and Dynamic Logical Partitioning on RPA platforms).
 *
 * Copyright (C) 2005 Nathan Lynch
 * Copyright (C) 2005 IBM Corporation
 *
 *
 *  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.
 */

#include <linux/kernel.h>
#include <linux/kref.h>
#include <linux/notifier.h>
#include <linux/proc_fs.h>
#include <linux/slab.h>

#include <asm/prom.h>
#include <asm/machdep.h>
#include <asm/uaccess.h>
#include <asm/pSeries_reconfig.h>
#include <asm/mmu.h>



/*
 * Routines for "runtime" addition and removal of device tree nodes.
 */
#ifdef CONFIG_PROC_DEVICETREE
/*
 * Add a node to /proc/device-tree.
 */
static void add_node_proc_entries(struct device_node *np)
{
    struct proc_dir_entry *ent;

    ent = proc_mkdir(strrchr(np->full_name, '/') + 1, np->parent->pde);
    if (ent)
        proc_device_tree_add_node(np, ent);
}

static void remove_node_proc_entries(struct device_node *np)
{
    struct property *pp = np->properties;
    struct device_node *parent = np->parent;

    while (pp) {
        remove_proc_entry(pp->name, np->pde);
        pp = pp->next;
    }
    if (np->pde)
        remove_proc_entry(np->pde->name, parent->pde);
}
#else /* !CONFIG_PROC_DEVICETREE */
static void add_node_proc_entries(struct device_node *np)
{
    return;
}

static void remove_node_proc_entries(struct device_node *np)
{
    return;
}
#endif /* CONFIG_PROC_DEVICETREE */

static struct device_node *derive_parent(const char *path)
{
    struct device_node *parent = NULL;
    char *parent_path = "/";
    size_t parent_path_len = strrchr(path, '/') - path + 1;

    /* reject if path is "/" */
    if (!strcmp(path, "/"))
        return ERR_PTR(-EINVAL);

    if (strrchr(path, '/') != path) {
        parent_path = kmalloc(parent_path_len, GFP_KERNEL);
        if (!parent_path)
            return ERR_PTR(-ENOMEM);
        strlcpy(parent_path, path, parent_path_len);
    }
    parent = of_find_node_by_path(parent_path);
    if (!parent)
        return ERR_PTR(-EINVAL);
    if (strcmp(parent_path, "/"))
        kfree(parent_path);
    return parent;
}

static BLOCKING_NOTIFIER_HEAD(pSeries_reconfig_chain);

int pSeries_reconfig_notifier_register(struct notifier_block *nb)
{
    return blocking_notifier_chain_register(&pSeries_reconfig_chain, nb);
}
EXPORT_SYMBOL_GPL(pSeries_reconfig_notifier_register);

void pSeries_reconfig_notifier_unregister(struct notifier_block *nb)
{
    blocking_notifier_chain_unregister(&pSeries_reconfig_chain, nb);
}
EXPORT_SYMBOL_GPL(pSeries_reconfig_notifier_unregister);

int pSeries_reconfig_notify(unsigned long action, void *p)
{
    int err = blocking_notifier_call_chain(&pSeries_reconfig_chain,
                        action, p);

    return notifier_to_errno(err);
}

static int pSeries_reconfig_add_node(const char *path, struct property *proplist)
{
    struct device_node *np;
    int err = -ENOMEM;

    np = kzalloc(sizeof(*np), GFP_KERNEL);
    if (!np)
        goto out_err;

    np->full_name = kstrdup(path, GFP_KERNEL);
    if (!np->full_name)
        goto out_err;

    np->properties = proplist;
    of_node_set_flag(np, OF_DYNAMIC);
    kref_init(&np->kref);

    np->parent = derive_parent(path);
    if (IS_ERR(np->parent)) {
        err = PTR_ERR(np->parent);
        goto out_err;
    }

    err = pSeries_reconfig_notify(PSERIES_RECONFIG_ADD, np);
    if (err) {
        printk(KERN_ERR "Failed to add device node %s\n", path);
        goto out_err;
    }

    of_attach_node(np);

    add_node_proc_entries(np);

    of_node_put(np->parent);

    return 0;

out_err:
    if (np) {
        of_node_put(np->parent);
        kfree(np->full_name);
        kfree(np);
    }
    return err;
}

static int pSeries_reconfig_remove_node(struct device_node *np)
{
    struct device_node *parent, *child;

    parent = of_get_parent(np);
    if (!parent)
        return -EINVAL;

    if ((child = of_get_next_child(np, NULL))) {
        of_node_put(child);
        of_node_put(parent);
        return -EBUSY;
    }

    remove_node_proc_entries(np);

    pSeries_reconfig_notify(PSERIES_RECONFIG_REMOVE, np);
    of_detach_node(np);

    of_node_put(parent);
    of_node_put(np); /* Must decrement the refcount */
    return 0;
}

/*
 * /proc/powerpc/ofdt - yucky binary interface for adding and removing
 * OF device nodes.  Should be deprecated as soon as we get an
 * in-kernel wrapper for the RTAS ibm,configure-connector call.
 */

static void release_prop_list(const struct property *prop)
{
    struct property *next;
    for (; prop; prop = next) {
        next = prop->next;
        kfree(prop->name);
        kfree(prop->value);
        kfree(prop);
    }

}

static char * parse_next_property(char *buf, char *end, char **name, int *length,
                  unsigned char **value)
{
    char *tmp;

    *name = buf;

    tmp = strchr(buf, ' ');
    if (!tmp) {
        printk(KERN_ERR "property parse failed in %s at line %d\n",
               __func__, __LINE__);
        return NULL;
    }
    *tmp = '\0';

    if (++tmp >= end) {
        printk(KERN_ERR "property parse failed in %s at line %d\n",
               __func__, __LINE__);
        return NULL;
    }

    /* now we're on the length */
    *length = -1;
    *length = simple_strtoul(tmp, &tmp, 10);
    if (*length == -1) {
        printk(KERN_ERR "property parse failed in %s at line %d\n",
               __func__, __LINE__);
        return NULL;
    }
    if (*tmp != ' ' || ++tmp >= end) {
        printk(KERN_ERR "property parse failed in %s at line %d\n",
               __func__, __LINE__);
        return NULL;
    }

    /* now we're on the value */
    *value = tmp;
    tmp += *length;
    if (tmp > end) {
        printk(KERN_ERR "property parse failed in %s at line %d\n",
               __func__, __LINE__);
        return NULL;
    }
    else if (tmp < end && *tmp != ' ' && *tmp != '\0') {
        printk(KERN_ERR "property parse failed in %s at line %d\n",
               __func__, __LINE__);
        return NULL;
    }
    tmp++;

    /* and now we should be on the next name, or the end */
    return tmp;
}

static struct property *new_property(const char *name, const int length,
                     const unsigned char *value, struct property *last)
{
    struct property *new = kzalloc(sizeof(*new), GFP_KERNEL);

    if (!new)
        return NULL;

    if (!(new->name = kmalloc(strlen(name) + 1, GFP_KERNEL)))
        goto cleanup;
    if (!(new->value = kmalloc(length + 1, GFP_KERNEL)))
        goto cleanup;

    strcpy(new->name, name);
    memcpy(new->value, value, length);
    *(((char *)new->value) + length) = 0;
    new->length = length;
    new->next = last;
    return new;

cleanup:
    kfree(new->name);
    kfree(new->value);
    kfree(new);
    return NULL;
}

static int do_add_node(char *buf, size_t bufsize)
{
    char *path, *end, *name;
    struct device_node *np;
    struct property *prop = NULL;
    unsigned char* value;
    int length, rv = 0;

    end = buf + bufsize;
    path = buf;
    buf = strchr(buf, ' ');
    if (!buf)
        return -EINVAL;
    *buf = '\0';
    buf++;

    if ((np = of_find_node_by_path(path))) {
        of_node_put(np);
        return -EINVAL;
    }

    /* rv = build_prop_list(tmp, bufsize - (tmp - buf), &proplist); */
    while (buf < end &&
           (buf = parse_next_property(buf, end, &name, &length, &value))) {
        struct property *last = prop;

        prop = new_property(name, length, value, last);
        if (!prop) {
            rv = -ENOMEM;
            prop = last;
            goto out;
        }
    }
    if (!buf) {
        rv = -EINVAL;
        goto out;
    }

    rv = pSeries_reconfig_add_node(path, prop);

out:
    if (rv)
        release_prop_list(prop);
    return rv;
}

static int do_remove_node(char *buf)
{
    struct device_node *node;
    int rv = -ENODEV;

    if ((node = of_find_node_by_path(buf)))
        rv = pSeries_reconfig_remove_node(node);

    of_node_put(node);
    return rv;
}

static char *parse_node(char *buf, size_t bufsize, struct device_node **npp)
{
    char *handle_str;
    phandle handle;
    *npp = NULL;

    handle_str = buf;

    buf = strchr(buf, ' ');
    if (!buf)
        return NULL;
    *buf = '\0';
    buf++;

    handle = simple_strtoul(handle_str, NULL, 0);

    *npp = of_find_node_by_phandle(handle);
    return buf;
}

static int do_add_property(char *buf, size_t bufsize)
{
    struct property *prop = NULL;
    struct device_node *np;
    unsigned char *value;
    char *name, *end;
    int length;
    end = buf + bufsize;
    buf = parse_node(buf, bufsize, &np);

    if (!np)
        return -ENODEV;

    if (parse_next_property(buf, end, &name, &length, &value) == NULL)
        return -EINVAL;

    prop = new_property(name, length, value, NULL);
    if (!prop)
        return -ENOMEM;

    prom_add_property(np, prop);

    return 0;
}

static int do_remove_property(char *buf, size_t bufsize)
{
    struct device_node *np;
    char *tmp;
    struct property *prop;
    buf = parse_node(buf, bufsize, &np);

    if (!np)
        return -ENODEV;

    tmp = strchr(buf,' ');
    if (tmp)
        *tmp = '\0';

    if (strlen(buf) == 0)
        return -EINVAL;

    prop = of_find_property(np, buf, NULL);

    return prom_remove_property(np, prop);
}

static int do_update_property(char *buf, size_t bufsize)
{
    struct device_node *np;
    struct pSeries_reconfig_prop_update upd_value;
    unsigned char *value;
    char *name, *end, *next_prop;
    int rc, length;
    struct property *newprop;
    buf = parse_node(buf, bufsize, &np);
    end = buf + bufsize;

    if (!np)
        return -ENODEV;

    next_prop = parse_next_property(buf, end, &name, &length, &value);
    if (!next_prop)
        return -EINVAL;

    if (!strlen(name))
        return -ENODEV;

    newprop = new_property(name, length, value, NULL);
    if (!newprop)
        return -ENOMEM;

    if (!strcmp(name, "slb-size") || !strcmp(name, "ibm,slb-size"))
        slb_set_size(*(int *)value);

    upd_value.node = np;
    upd_value.property = newprop;
    pSeries_reconfig_notify(PSERIES_UPDATE_PROPERTY, &upd_value);

    rc = prom_update_property(np, newprop);
    if (rc)
        return rc;

    /* For memory under the ibm,dynamic-reconfiguration-memory node
     * of the device tree, adding and removing memory is just an update
     * to the ibm,dynamic-memory property instead of adding/removing a
     * memory node in the device tree.  For these cases we still need to
     * involve the notifier chain.
     */
    if (!strcmp(name, "ibm,dynamic-memory")) {
        int action;

        next_prop = parse_next_property(next_prop, end, &name,
                        &length, &value);
        if (!next_prop)
            return -EINVAL;

        if (!strcmp(name, "add"))
            action = PSERIES_DRCONF_MEM_ADD;
        else
            action = PSERIES_DRCONF_MEM_REMOVE;

        rc = pSeries_reconfig_notify(action, value);
        if (rc) {
            prom_update_property(np, newprop);
            return rc;
        }
    }

    return 0;
}

static ssize_t ofdt_write(struct file *file, const char __user *buf, size_t count,
              loff_t *off)
{
    int rv = 0;
    char *kbuf;
    char *tmp;

    if (!(kbuf = kmalloc(count + 1, GFP_KERNEL))) {
        rv = -ENOMEM;
        goto out;
    }
    if (copy_from_user(kbuf, buf, count)) {
        rv = -EFAULT;
        goto out;
    }

    kbuf[count] = '\0';

    tmp = strchr(kbuf, ' ');
    if (!tmp) {
        rv = -EINVAL;
        goto out;
    }
    *tmp = '\0';
    tmp++;

    if (!strcmp(kbuf, "add_node"))
        rv = do_add_node(tmp, count - (tmp - kbuf));
    else if (!strcmp(kbuf, "remove_node"))
        rv = do_remove_node(tmp);
    else if (!strcmp(kbuf, "add_property"))
        rv = do_add_property(tmp, count - (tmp - kbuf));
    else if (!strcmp(kbuf, "remove_property"))
        rv = do_remove_property(tmp, count - (tmp - kbuf));
    else if (!strcmp(kbuf, "update_property"))
        rv = do_update_property(tmp, count - (tmp - kbuf));
    else
        rv = -EINVAL;
out:
    kfree(kbuf);
    return rv ? rv : count;
}

static const struct file_operations ofdt_fops = {
    .write = ofdt_write,
    .llseek = noop_llseek,
};

/* create /proc/powerpc/ofdt write-only by root */
static int proc_ppc64_create_ofdt(void)
{
    struct proc_dir_entry *ent;

    if (!machine_is(pseries))
        return 0;

    ent = proc_create("powerpc/ofdt", S_IWUSR, NULL, &ofdt_fops);
    if (ent)
        ent->size = 0;

    return 0;
}
__initcall(proc_ppc64_create_ofdt);