/**************************************************************************
 *
 * Copyright (c) 2007-2010 VMware, Inc., Palo Alto, CA., USA
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sub license, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 * USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 **************************************************************************/
/*
 * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
 */

#include <drm/ttm/ttm_module.h>
#include <drm/ttm/ttm_bo_driver.h>
#include <drm/ttm/ttm_placement.h>
#include <drm/drm_mm.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/module.h>

/**
 * Currently we use a spinlock for the lock, but a mutex *may* be
 * more appropriate to reduce scheduling latency if the range manager
 * ends up with very fragmented allocation patterns.
 */

struct ttm_range_manager {
        struct drm_mm mm;
        spinlock_t lock;
};

static int ttm_bo_man_get_node(struct ttm_mem_type_manager *man,
                               struct ttm_buffer_object *bo,
                               const struct ttm_place *place,
                               struct ttm_mem_reg *mem)
{
        struct ttm_range_manager *rman = (struct ttm_range_manager *) man->priv;
        struct drm_mm *mm = &rman->mm;
        struct drm_mm_node *node;
        enum drm_mm_insert_mode mode;
        unsigned long lpfn;
        int ret;

        lpfn = place->lpfn;
        if (!lpfn)
                lpfn = man->size;

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

        mode = DRM_MM_INSERT_BEST;
        if (place->flags & TTM_PL_FLAG_TOPDOWN)
                mode = DRM_MM_INSERT_HIGH;

        lockmgr(&rman->lock, LK_EXCLUSIVE);
        ret = drm_mm_insert_node_in_range(mm, node,
                                          mem->num_pages,
                                          mem->page_alignment, 0,
                                          place->fpfn, lpfn, mode);
        lockmgr(&rman->lock, LK_RELEASE);

        if (unlikely(ret)) {
                kfree(node);
        } else {
                mem->mm_node = node;
                mem->start = node->start;
        }

        return 0;
}

static void ttm_bo_man_put_node(struct ttm_mem_type_manager *man,
                                struct ttm_mem_reg *mem)
{
        struct ttm_range_manager *rman = (struct ttm_range_manager *) man->priv;

        if (mem->mm_node) {
                lockmgr(&rman->lock, LK_EXCLUSIVE);
                drm_mm_remove_node(mem->mm_node);
                lockmgr(&rman->lock, LK_RELEASE);

                kfree(mem->mm_node);
                mem->mm_node = NULL;
        }
}

static int ttm_bo_man_init(struct ttm_mem_type_manager *man,
                           unsigned long p_size)
{
        struct ttm_range_manager *rman;

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

        drm_mm_init(&rman->mm, 0, p_size);
        lockinit(&rman->lock, "ttmrman", 0, 0);
        man->priv = rman;
        return 0;
}

static int ttm_bo_man_takedown(struct ttm_mem_type_manager *man)
{
        struct ttm_range_manager *rman = (struct ttm_range_manager *) man->priv;
        struct drm_mm *mm = &rman->mm;

        lockmgr(&rman->lock, LK_EXCLUSIVE);
        if (drm_mm_clean(mm)) {
                drm_mm_takedown(mm);
                lockmgr(&rman->lock, LK_RELEASE);
                kfree(rman);
                man->priv = NULL;
                return 0;
        }
        lockmgr(&rman->lock, LK_RELEASE);
        return -EBUSY;
}

static void ttm_bo_man_debug(struct ttm_mem_type_manager *man,
                             struct drm_printer *printer)
{
        struct ttm_range_manager *rman = (struct ttm_range_manager *) man->priv;

        lockmgr(&rman->lock, LK_EXCLUSIVE);
        drm_mm_print(&rman->mm, printer);
        lockmgr(&rman->lock, LK_RELEASE);
}

const struct ttm_mem_type_manager_func ttm_bo_manager_func = {
        .init = ttm_bo_man_init,
        .takedown = ttm_bo_man_takedown,
        .get_node = ttm_bo_man_get_node,
        .put_node = ttm_bo_man_put_node,
        .debug = ttm_bo_man_debug
};
EXPORT_SYMBOL(ttm_bo_manager_func);