/* SPDX-License-Identifier: GPL-2.0 OR MIT */
/**************************************************************************
 *
 * 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_device.h>
#include <drm/ttm/ttm_placement.h>
#include <drm/ttm/ttm_range_manager.h>
#include <drm/ttm/ttm_bo.h>
#include <drm/drm_mm.h>

#include <linux/export.h>
#include <linux/slab.h>
#include <linux/spinlock.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 ttm_resource_manager manager;
        struct drm_mm mm;
        spinlock_t lock;
};

static inline struct ttm_range_manager *
to_range_manager(struct ttm_resource_manager *man)
{
        return container_of(man, struct ttm_range_manager, manager);
}

static int ttm_range_man_alloc(struct ttm_resource_manager *man,
                               struct ttm_buffer_object *bo,
                               const struct ttm_place *place,
                               struct ttm_resource **res)
{
        struct ttm_range_manager *rman = to_range_manager(man);
        struct ttm_range_mgr_node *node;
        struct drm_mm *mm = &rman->mm;
        enum drm_mm_insert_mode mode;
        unsigned long lpfn;
        int ret;

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

        node = kzalloc_flex(*node, mm_nodes, 1);
        if (!node)
                return -ENOMEM;

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

        ttm_resource_init(bo, place, &node->base);

        spin_lock(&rman->lock);
        ret = drm_mm_insert_node_in_range(mm, &node->mm_nodes[0],
                                          PFN_UP(node->base.size),
                                          bo->page_alignment, 0,
                                          place->fpfn, lpfn, mode);
        spin_unlock(&rman->lock);

        if (unlikely(ret)) {
                ttm_resource_fini(man, &node->base);
                kfree(node);
                return ret;
        }

        node->base.start = node->mm_nodes[0].start;
        *res = &node->base;
        return 0;
}

static void ttm_range_man_free(struct ttm_resource_manager *man,
                               struct ttm_resource *res)
{
        struct ttm_range_mgr_node *node = to_ttm_range_mgr_node(res);
        struct ttm_range_manager *rman = to_range_manager(man);

        spin_lock(&rman->lock);
        drm_mm_remove_node(&node->mm_nodes[0]);
        spin_unlock(&rman->lock);

        ttm_resource_fini(man, res);
        kfree(node);
}

static bool ttm_range_man_intersects(struct ttm_resource_manager *man,
                                     struct ttm_resource *res,
                                     const struct ttm_place *place,
                                     size_t size)
{
        struct drm_mm_node *node = &to_ttm_range_mgr_node(res)->mm_nodes[0];
        u32 num_pages = PFN_UP(size);

        /* Don't evict BOs outside of the requested placement range */
        if (place->fpfn >= (node->start + num_pages) ||
            (place->lpfn && place->lpfn <= node->start))
                return false;

        return true;
}

static bool ttm_range_man_compatible(struct ttm_resource_manager *man,
                                     struct ttm_resource *res,
                                     const struct ttm_place *place,
                                     size_t size)
{
        struct drm_mm_node *node = &to_ttm_range_mgr_node(res)->mm_nodes[0];
        u32 num_pages = PFN_UP(size);

        if (node->start < place->fpfn ||
            (place->lpfn && (node->start + num_pages) > place->lpfn))
                return false;

        return true;
}

static void ttm_range_man_debug(struct ttm_resource_manager *man,
                                struct drm_printer *printer)
{
        struct ttm_range_manager *rman = to_range_manager(man);

        spin_lock(&rman->lock);
        drm_mm_print(&rman->mm, printer);
        spin_unlock(&rman->lock);
}

static const struct ttm_resource_manager_func ttm_range_manager_func = {
        .alloc = ttm_range_man_alloc,
        .free = ttm_range_man_free,
        .intersects = ttm_range_man_intersects,
        .compatible = ttm_range_man_compatible,
        .debug = ttm_range_man_debug
};

/**
 * ttm_range_man_init_nocheck - Initialise a generic range manager for the
 * selected memory type.
 *
 * @bdev: ttm device
 * @type: memory manager type
 * @use_tt: if the memory manager uses tt
 * @p_size: size of area to be managed in pages.
 *
 * The range manager is installed for this device in the type slot.
 *
 * Return: %0 on success or a negative error code on failure
 */
int ttm_range_man_init_nocheck(struct ttm_device *bdev,
                       unsigned type, bool use_tt,
                       unsigned long p_size)
{
        struct ttm_resource_manager *man;
        struct ttm_range_manager *rman;

        rman = kzalloc_obj(*rman);
        if (!rman)
                return -ENOMEM;

        man = &rman->manager;
        man->use_tt = use_tt;

        man->func = &ttm_range_manager_func;

        ttm_resource_manager_init(man, bdev, p_size);

        drm_mm_init(&rman->mm, 0, p_size);
        spin_lock_init(&rman->lock);

        ttm_set_driver_manager(bdev, type, &rman->manager);
        ttm_resource_manager_set_used(man, true);
        return 0;
}
EXPORT_SYMBOL(ttm_range_man_init_nocheck);

/**
 * ttm_range_man_fini_nocheck - Remove the generic range manager from a slot
 * and tear it down.
 *
 * @bdev: ttm device
 * @type: memory manager type
 *
 * Return: %0 on success or a negative error code on failure
 */
int ttm_range_man_fini_nocheck(struct ttm_device *bdev,
                       unsigned type)
{
        struct ttm_resource_manager *man = ttm_manager_type(bdev, type);
        struct ttm_range_manager *rman = to_range_manager(man);
        struct drm_mm *mm = &rman->mm;
        int ret;

        if (!man)
                return 0;

        ttm_resource_manager_set_used(man, false);

        ret = ttm_resource_manager_evict_all(bdev, man);
        if (ret)
                return ret;

        spin_lock(&rman->lock);
        drm_mm_takedown(mm);
        spin_unlock(&rman->lock);

        ttm_resource_manager_cleanup(man);
        ttm_set_driver_manager(bdev, type, NULL);
        kfree(rman);
        return 0;
}
EXPORT_SYMBOL(ttm_range_man_fini_nocheck);