scom.c

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/*
 * Copyright 2010 Benjamin Herrenschmidt, IBM Corp
 *                <[email protected]>
 *     and        David Gibson, IBM Corporation.
 *
 *   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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <linux/kernel.h>
#include <linux/debugfs.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <asm/debug.h>
#include <asm/prom.h>
#include <asm/scom.h>

const struct scom_controller *scom_controller;
EXPORT_SYMBOL_GPL(scom_controller);

struct device_node *scom_find_parent(struct device_node *node)
{
    struct device_node *par, *tmp;
    const u32 *p;

    for (par = of_node_get(node); par;) {
        if (of_get_property(par, "scom-controller", NULL))
            break;
        p = of_get_property(par, "scom-parent", NULL);
        tmp = par;
        if (p == NULL)
            par = of_get_parent(par);
        else
            par = of_find_node_by_phandle(*p);
        of_node_put(tmp);
    }
    return par;
}
EXPORT_SYMBOL_GPL(scom_find_parent);

scom_map_t scom_map_device(struct device_node *dev, int index)
{
    struct device_node *parent;
    unsigned int cells, size;
    const u32 *prop;
    u64 reg, cnt;
    scom_map_t ret;

    parent = scom_find_parent(dev);

    if (parent == NULL)
        return 0;

    prop = of_get_property(parent, "#scom-cells", NULL);
    cells = prop ? *prop : 1;

    prop = of_get_property(dev, "scom-reg", &size);
    if (!prop)
        return 0;
    size >>= 2;

    if (index >= (size / (2*cells)))
        return 0;

    reg = of_read_number(&prop[index * cells * 2], cells);
    cnt = of_read_number(&prop[index * cells * 2 + cells], cells);

    ret = scom_map(parent, reg, cnt);
    of_node_put(parent);

    return ret;
}
EXPORT_SYMBOL_GPL(scom_map_device);

#ifdef CONFIG_SCOM_DEBUGFS
struct scom_debug_entry {
    struct device_node *dn;
    unsigned long addr;
    scom_map_t map;
    spinlock_t lock;
    char name[8];
    struct debugfs_blob_wrapper blob;
};

static int scom_addr_set(void *data, u64 val)
{
    struct scom_debug_entry *ent = data;

    ent->addr = 0;
    scom_unmap(ent->map);

    ent->map = scom_map(ent->dn, val, 1);
    if (scom_map_ok(ent->map))
        ent->addr = val;
    else
        return -EFAULT;

    return 0;
}

static int scom_addr_get(void *data, u64 *val)
{
    struct scom_debug_entry *ent = data;
    *val = ent->addr;
    return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(scom_addr_fops, scom_addr_get, scom_addr_set,
            "0x%llx\n");

static int scom_val_set(void *data, u64 val)
{
    struct scom_debug_entry *ent = data;

    if (!scom_map_ok(ent->map))
        return -EFAULT;

    scom_write(ent->map, 0, val);

    return 0;
}

static int scom_val_get(void *data, u64 *val)
{
    struct scom_debug_entry *ent = data;

    if (!scom_map_ok(ent->map))
        return -EFAULT;

    *val = scom_read(ent->map, 0);
    return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(scom_val_fops, scom_val_get, scom_val_set,
            "0x%llx\n");

static int scom_debug_init_one(struct dentry *root, struct device_node *dn,
                   int i)
{
    struct scom_debug_entry *ent;
    struct dentry *dir;

    ent = kzalloc(sizeof(*ent), GFP_KERNEL);
    if (!ent)
        return -ENOMEM;

    ent->dn = of_node_get(dn);
    ent->map = SCOM_MAP_INVALID;
    spin_lock_init(&ent->lock);
    snprintf(ent->name, 8, "scom%d", i);
    ent->blob.data = dn->full_name;
    ent->blob.size = strlen(dn->full_name);

    dir = debugfs_create_dir(ent->name, root);
    if (!dir) {
        of_node_put(dn);
        kfree(ent);
        return -1;
    }

    debugfs_create_file("addr", 0600, dir, ent, &scom_addr_fops);
    debugfs_create_file("value", 0600, dir, ent, &scom_val_fops);
    debugfs_create_blob("path", 0400, dir, &ent->blob);

    return 0;
}

static int scom_debug_init(void)
{
    struct device_node *dn;
    struct dentry *root;
    int i, rc;

    root = debugfs_create_dir("scom", powerpc_debugfs_root);
    if (!root)
        return -1;

    i = rc = 0;
    for_each_node_with_property(dn, "scom-controller")
        rc |= scom_debug_init_one(root, dn, i++);

    return rc;
}
device_initcall(scom_debug_init);
#endif /* CONFIG_SCOM_DEBUGFS */