/*
 * Copyright 2016 Advanced Micro Devices, Inc.
 *
 * 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, sublicense,
 * 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 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 NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) 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: Christian König
 */

#include <drm/drmP.h>
#include "amdgpu.h"

struct amdgpu_gtt_mgr {
        struct drm_mm mm;
        spinlock_t lock;
        uint64_t available;
};

/**
 * amdgpu_gtt_mgr_init - init GTT manager and DRM MM
 *
 * @man: TTM memory type manager
 * @p_size: maximum size of GTT
 *
 * Allocate and initialize the GTT manager.
 */
static int amdgpu_gtt_mgr_init(struct ttm_mem_type_manager *man,
                               unsigned long p_size)
{
        struct amdgpu_gtt_mgr *mgr;

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

        drm_mm_init(&mgr->mm, 0, p_size);
        spin_lock_init(&mgr->lock);
        mgr->available = p_size;
        man->priv = mgr;
        return 0;
}

/**
 * amdgpu_gtt_mgr_fini - free and destroy GTT manager
 *
 * @man: TTM memory type manager
 *
 * Destroy and free the GTT manager, returns -EBUSY if ranges are still
 * allocated inside it.
 */
static int amdgpu_gtt_mgr_fini(struct ttm_mem_type_manager *man)
{
        struct amdgpu_gtt_mgr *mgr = man->priv;

        spin_lock(&mgr->lock);
        if (!drm_mm_clean(&mgr->mm)) {
                spin_unlock(&mgr->lock);
                return -EBUSY;
        }

        drm_mm_takedown(&mgr->mm);
        spin_unlock(&mgr->lock);
        kfree(mgr);
        man->priv = NULL;
        return 0;
}

/**
 * amdgpu_gtt_mgr_alloc - allocate new ranges
 *
 * @man: TTM memory type manager
 * @tbo: TTM BO we need this range for
 * @place: placement flags and restrictions
 * @mem: the resulting mem object
 *
 * Allocate the address space for a node.
 */
int amdgpu_gtt_mgr_alloc(struct ttm_mem_type_manager *man,
                         struct ttm_buffer_object *tbo,
                         const struct ttm_place *place,
                         struct ttm_mem_reg *mem)
{
        struct amdgpu_gtt_mgr *mgr = man->priv;
        struct drm_mm_node *node = mem->mm_node;
        enum drm_mm_insert_mode mode;
        unsigned long fpfn, lpfn;
        int r;

        if (node->start != AMDGPU_BO_INVALID_OFFSET)
                return 0;

        if (place)
                fpfn = place->fpfn;
        else
                fpfn = 0;

        if (place && place->lpfn)
                lpfn = place->lpfn;
        else
                lpfn = man->size;

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

        spin_lock(&mgr->lock);
        r = drm_mm_insert_node_in_range(&mgr->mm, node,
                                        mem->num_pages, mem->page_alignment, 0,
                                        fpfn, lpfn, mode);
        spin_unlock(&mgr->lock);

        if (!r) {
                mem->start = node->start;
                if (&tbo->mem == mem)
                        tbo->offset = (tbo->mem.start << PAGE_SHIFT) +
                            tbo->bdev->man[tbo->mem.mem_type].gpu_offset;
        }

        return r;
}

void amdgpu_gtt_mgr_print(struct seq_file *m, struct ttm_mem_type_manager *man)
{
        struct amdgpu_device *adev = amdgpu_ttm_adev(man->bdev);
        struct amdgpu_gtt_mgr *mgr = man->priv;

        seq_printf(m, "man size:%llu pages, gtt available:%llu pages, usage:%lluMB\n",
                   man->size, mgr->available, (u64)atomic64_read(&adev->gtt_usage) >> 20);

}
/**
 * amdgpu_gtt_mgr_new - allocate a new node
 *
 * @man: TTM memory type manager
 * @tbo: TTM BO we need this range for
 * @place: placement flags and restrictions
 * @mem: the resulting mem object
 *
 * Dummy, allocate the node but no space for it yet.
 */
static int amdgpu_gtt_mgr_new(struct ttm_mem_type_manager *man,
                              struct ttm_buffer_object *tbo,
                              const struct ttm_place *place,
                              struct ttm_mem_reg *mem)
{
        struct amdgpu_gtt_mgr *mgr = man->priv;
        struct drm_mm_node *node;
        int r;

        spin_lock(&mgr->lock);
        if (mgr->available < mem->num_pages) {
                spin_unlock(&mgr->lock);
                return 0;
        }
        mgr->available -= mem->num_pages;
        spin_unlock(&mgr->lock);

        node = kzalloc(sizeof(*node), GFP_KERNEL);
        if (!node) {
                r = -ENOMEM;
                goto err_out;
        }

        node->start = AMDGPU_BO_INVALID_OFFSET;
        node->size = mem->num_pages;
        mem->mm_node = node;

        if (place->fpfn || place->lpfn || place->flags & TTM_PL_FLAG_TOPDOWN) {
                r = amdgpu_gtt_mgr_alloc(man, tbo, place, mem);
                if (unlikely(r)) {
                        kfree(node);
                        mem->mm_node = NULL;
                        r = 0;
                        goto err_out;
                }
        } else {
                mem->start = node->start;
        }

        return 0;
err_out:
        spin_lock(&mgr->lock);
        mgr->available += mem->num_pages;
        spin_unlock(&mgr->lock);

        return r;
}

/**
 * amdgpu_gtt_mgr_del - free ranges
 *
 * @man: TTM memory type manager
 * @tbo: TTM BO we need this range for
 * @place: placement flags and restrictions
 * @mem: TTM memory object
 *
 * Free the allocated GTT again.
 */
static void amdgpu_gtt_mgr_del(struct ttm_mem_type_manager *man,
                               struct ttm_mem_reg *mem)
{
        struct amdgpu_gtt_mgr *mgr = man->priv;
        struct drm_mm_node *node = mem->mm_node;

        if (!node)
                return;

        spin_lock(&mgr->lock);
        if (node->start != AMDGPU_BO_INVALID_OFFSET)
                drm_mm_remove_node(node);
        mgr->available += mem->num_pages;
        spin_unlock(&mgr->lock);

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

/**
 * amdgpu_gtt_mgr_debug - dump VRAM table
 *
 * @man: TTM memory type manager
 * @prefix: text prefix
 *
 * Dump the table content using printk.
 */
static void amdgpu_gtt_mgr_debug(struct ttm_mem_type_manager *man,
                                  const char *prefix)
{
        struct amdgpu_gtt_mgr *mgr = man->priv;
        struct drm_printer p = drm_debug_printer(prefix);

        spin_lock(&mgr->lock);
        drm_mm_print(&mgr->mm, &p);
        spin_unlock(&mgr->lock);
}

const struct ttm_mem_type_manager_func amdgpu_gtt_mgr_func = {
        .init = amdgpu_gtt_mgr_init,
        .takedown = amdgpu_gtt_mgr_fini,
        .get_node = amdgpu_gtt_mgr_new,
        .put_node = amdgpu_gtt_mgr_del,
        .debug = amdgpu_gtt_mgr_debug
};