/*
 * Copyright(c) 2015, 2016 Intel Corporation.
 *
 * This file is provided under a dual BSD/GPLv2 license.  When using or
 * redistributing this file, you may do so under either license.
 *
 * GPL LICENSE SUMMARY
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * 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.
 *
 * BSD LICENSE
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *  - Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  - Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *  - Neither the name of Intel Corporation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#include <linux/cdev.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/fs.h>

#include "hfi.h"
#include "device.h"

static struct class *class;
static struct class *user_class;
static dev_t hfi1_dev;

int hfi1_cdev_init(int minor, const char *name,
                   const struct file_operations *fops,
                   struct cdev *cdev, struct device **devp,
                   bool user_accessible,
                   struct kobject *parent)
{
        const dev_t dev = MKDEV(MAJOR(hfi1_dev), minor);
        struct device *device = NULL;
        int ret;

        cdev_init(cdev, fops);
        cdev->owner = THIS_MODULE;
        cdev_set_parent(cdev, parent);
        kobject_set_name(&cdev->kobj, name);

        ret = cdev_add(cdev, dev, 1);
        if (ret < 0) {
                pr_err("Could not add cdev for minor %d, %s (err %d)\n",
                       minor, name, -ret);
                goto done;
        }

        if (user_accessible)
                device = device_create(user_class, NULL, dev, NULL, "%s", name);
        else
                device = device_create(class, NULL, dev, NULL, "%s", name);

        if (IS_ERR(device)) {
                ret = PTR_ERR(device);
                device = NULL;
                pr_err("Could not create device for minor %d, %s (err %d)\n",
                        minor, name, -ret);
                cdev_del(cdev);
        }
done:
        *devp = device;
        return ret;
}

void hfi1_cdev_cleanup(struct cdev *cdev, struct device **devp)
{
        struct device *device = *devp;

        if (device) {
                device_unregister(device);
                *devp = NULL;

                cdev_del(cdev);
        }
}

static const char *hfi1_class_name = "hfi1";

const char *class_name(void)
{
        return hfi1_class_name;
}

static char *hfi1_devnode(struct device *dev, umode_t *mode)
{
        if (mode)
                *mode = 0600;
        return kasprintf(GFP_KERNEL, "%s", dev_name(dev));
}

static const char *hfi1_class_name_user = "hfi1_user";
static const char *class_name_user(void)
{
        return hfi1_class_name_user;
}

static char *hfi1_user_devnode(struct device *dev, umode_t *mode)
{
        if (mode)
                *mode = 0666;
        return kasprintf(GFP_KERNEL, "%s", dev_name(dev));
}

int __init dev_init(void)
{
        int ret;

        ret = alloc_chrdev_region(&hfi1_dev, 0, HFI1_NMINORS, DRIVER_NAME);
        if (ret < 0) {
                pr_err("Could not allocate chrdev region (err %d)\n", -ret);
                goto done;
        }

        class = class_create(THIS_MODULE, class_name());
        if (IS_ERR(class)) {
                ret = PTR_ERR(class);
                pr_err("Could not create device class (err %d)\n", -ret);
                unregister_chrdev_region(hfi1_dev, HFI1_NMINORS);
                goto done;
        }
        class->devnode = hfi1_devnode;

        user_class = class_create(THIS_MODULE, class_name_user());
        if (IS_ERR(user_class)) {
                ret = PTR_ERR(user_class);
                pr_err("Could not create device class for user accessible files (err %d)\n",
                       -ret);
                class_destroy(class);
                class = NULL;
                user_class = NULL;
                unregister_chrdev_region(hfi1_dev, HFI1_NMINORS);
                goto done;
        }
        user_class->devnode = hfi1_user_devnode;

done:
        return ret;
}

void dev_cleanup(void)
{
        class_destroy(class);
        class = NULL;

        class_destroy(user_class);
        user_class = NULL;

        unregister_chrdev_region(hfi1_dev, HFI1_NMINORS);
}