dca-sysfs.c

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/*
 * Copyright(c) 2007 - 2009 Intel Corporation. All rights reserved.
 *
 * 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.
 *
 * The full GNU General Public License is included in this distribution in the
 * file called COPYING.
 */

#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <linux/device.h>
#include <linux/idr.h>
#include <linux/kdev_t.h>
#include <linux/err.h>
#include <linux/dca.h>
#include <linux/gfp.h>
#include <linux/export.h>

static struct class *dca_class;
static struct idr dca_idr;
static spinlock_t dca_idr_lock;

int dca_sysfs_add_req(struct dca_provider *dca, struct device *dev, int slot)
{
    struct device *cd;
    static int req_count;

    cd = device_create(dca_class, dca->cd, MKDEV(0, slot + 1), NULL,
               "requester%d", req_count++);
    if (IS_ERR(cd))
        return PTR_ERR(cd);
    return 0;
}

void dca_sysfs_remove_req(struct dca_provider *dca, int slot)
{
    device_destroy(dca_class, MKDEV(0, slot + 1));
}

int dca_sysfs_add_provider(struct dca_provider *dca, struct device *dev)
{
    struct device *cd;
    int err = 0;

idr_try_again:
    if (!idr_pre_get(&dca_idr, GFP_KERNEL))
        return -ENOMEM;
    spin_lock(&dca_idr_lock);
    err = idr_get_new(&dca_idr, dca, &dca->id);
    spin_unlock(&dca_idr_lock);
    switch (err) {
    case 0:
        break;
    case -EAGAIN:
        goto idr_try_again;
    default:
        return err;
    }

    cd = device_create(dca_class, dev, MKDEV(0, 0), NULL, "dca%d", dca->id);
    if (IS_ERR(cd)) {
        spin_lock(&dca_idr_lock);
        idr_remove(&dca_idr, dca->id);
        spin_unlock(&dca_idr_lock);
        return PTR_ERR(cd);
    }
    dca->cd = cd;
    return 0;
}

void dca_sysfs_remove_provider(struct dca_provider *dca)
{
    device_unregister(dca->cd);
    dca->cd = NULL;
    spin_lock(&dca_idr_lock);
    idr_remove(&dca_idr, dca->id);
    spin_unlock(&dca_idr_lock);
}

int __init dca_sysfs_init(void)
{
    idr_init(&dca_idr);
    spin_lock_init(&dca_idr_lock);

    dca_class = class_create(THIS_MODULE, "dca");
    if (IS_ERR(dca_class)) {
        idr_destroy(&dca_idr);
        return PTR_ERR(dca_class);
    }
    return 0;
}

void __exit dca_sysfs_exit(void)
{
    class_destroy(dca_class);
    idr_destroy(&dca_idr);
}