/*
 * 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_vram_mgr {
        struct drm_mm mm;
        spinlock_t lock;
        atomic64_t usage;
        atomic64_t vis_usage;
};

/**
 * amdgpu_vram_mgr_init - init VRAM manager and DRM MM
 *
 * @man: TTM memory type manager
 * @p_size: maximum size of VRAM
 *
 * Allocate and initialize the VRAM manager.
 */
static int amdgpu_vram_mgr_init(struct ttm_mem_type_manager *man,
                                unsigned long p_size)
{
        struct amdgpu_vram_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);
        man->priv = mgr;
        return 0;
}

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

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

/**
 * amdgpu_vram_mgr_vis_size - Calculate visible node size
 *
 * @adev: amdgpu device structure
 * @node: MM node structure
 *
 * Calculate how many bytes of the MM node are inside visible VRAM
 */
static u64 amdgpu_vram_mgr_vis_size(struct amdgpu_device *adev,
                                    struct drm_mm_node *node)
{
        uint64_t start = node->start << PAGE_SHIFT;
        uint64_t end = (node->size + node->start) << PAGE_SHIFT;

        if (start >= adev->gmc.visible_vram_size)
                return 0;

        return (end > adev->gmc.visible_vram_size ?
                adev->gmc.visible_vram_size : end) - start;
}

/**
 * amdgpu_vram_mgr_new - 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 VRAM for the given BO.
 */
static int amdgpu_vram_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_device *adev = amdgpu_ttm_adev(man->bdev);
        struct amdgpu_vram_mgr *mgr = man->priv;
        struct drm_mm *mm = &mgr->mm;
        struct drm_mm_node *nodes;
        enum drm_mm_insert_mode mode;
        unsigned long lpfn, num_nodes, pages_per_node, pages_left;
        uint64_t usage = 0, vis_usage = 0;
        unsigned i;
        int r;

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

        if (place->flags & TTM_PL_FLAG_CONTIGUOUS ||
            amdgpu_vram_page_split == -1) {
                pages_per_node = ~0ul;
                num_nodes = 1;
        } else {
                pages_per_node = max((uint32_t)amdgpu_vram_page_split,
                                     mem->page_alignment);
                num_nodes = DIV_ROUND_UP(mem->num_pages, pages_per_node);
        }

        nodes = kcalloc(num_nodes, sizeof(*nodes), GFP_KERNEL);
        if (!nodes)
                return -ENOMEM;

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

        mem->start = 0;
        pages_left = mem->num_pages;

        spin_lock(&mgr->lock);
        for (i = 0; i < num_nodes; ++i) {
                unsigned long pages = min(pages_left, pages_per_node);
                uint32_t alignment = mem->page_alignment;
                unsigned long start;

                if (pages == pages_per_node)
                        alignment = pages_per_node;

                r = drm_mm_insert_node_in_range(mm, &nodes[i],
                                                pages, alignment, 0,
                                                place->fpfn, lpfn,
                                                mode);
                if (unlikely(r))
                        goto error;

                usage += nodes[i].size << PAGE_SHIFT;
                vis_usage += amdgpu_vram_mgr_vis_size(adev, &nodes[i]);

                /* Calculate a virtual BO start address to easily check if
                 * everything is CPU accessible.
                 */
                start = nodes[i].start + nodes[i].size;
                if (start > mem->num_pages)
                        start -= mem->num_pages;
                else
                        start = 0;
                mem->start = max(mem->start, start);
                pages_left -= pages;
        }
        spin_unlock(&mgr->lock);

        atomic64_add(usage, &mgr->usage);
        atomic64_add(vis_usage, &mgr->vis_usage);

        mem->mm_node = nodes;

        return 0;

error:
        while (i--)
                drm_mm_remove_node(&nodes[i]);
        spin_unlock(&mgr->lock);

        kfree(nodes);
        return r == -ENOSPC ? 0 : r;
}

/**
 * amdgpu_vram_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 VRAM again.
 */
static void amdgpu_vram_mgr_del(struct ttm_mem_type_manager *man,
                                struct ttm_mem_reg *mem)
{
        struct amdgpu_device *adev = amdgpu_ttm_adev(man->bdev);
        struct amdgpu_vram_mgr *mgr = man->priv;
        struct drm_mm_node *nodes = mem->mm_node;
        uint64_t usage = 0, vis_usage = 0;
        unsigned pages = mem->num_pages;

        if (!mem->mm_node)
                return;

        spin_lock(&mgr->lock);
        while (pages) {
                pages -= nodes->size;
                drm_mm_remove_node(nodes);
                usage += nodes->size << PAGE_SHIFT;
                vis_usage += amdgpu_vram_mgr_vis_size(adev, nodes);
                ++nodes;
        }
        spin_unlock(&mgr->lock);

        atomic64_sub(usage, &mgr->usage);
        atomic64_sub(vis_usage, &mgr->vis_usage);

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

/**
 * amdgpu_vram_mgr_usage - how many bytes are used in this domain
 *
 * @man: TTM memory type manager
 *
 * Returns how many bytes are used in this domain.
 */
uint64_t amdgpu_vram_mgr_usage(struct ttm_mem_type_manager *man)
{
        struct amdgpu_vram_mgr *mgr = man->priv;

        return atomic64_read(&mgr->usage);
}

/**
 * amdgpu_vram_mgr_vis_usage - how many bytes are used in the visible part
 *
 * @man: TTM memory type manager
 *
 * Returns how many bytes are used in the visible part of VRAM
 */
uint64_t amdgpu_vram_mgr_vis_usage(struct ttm_mem_type_manager *man)
{
        struct amdgpu_vram_mgr *mgr = man->priv;

        return atomic64_read(&mgr->vis_usage);
}

/**
 * amdgpu_vram_mgr_debug - dump VRAM table
 *
 * @man: TTM memory type manager
 * @printer: DRM printer to use
 *
 * Dump the table content using printk.
 */
static void amdgpu_vram_mgr_debug(struct ttm_mem_type_manager *man,
                                  struct drm_printer *printer)
{
        struct amdgpu_vram_mgr *mgr = man->priv;

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

        drm_printf(printer, "man size:%llu pages, ram usage:%lluMB, vis usage:%lluMB\n",
                   man->size, amdgpu_vram_mgr_usage(man) >> 20,
                   amdgpu_vram_mgr_vis_usage(man) >> 20);
}

const struct ttm_mem_type_manager_func amdgpu_vram_mgr_func = {
        .init           = amdgpu_vram_mgr_init,
        .takedown       = amdgpu_vram_mgr_fini,
        .get_node       = amdgpu_vram_mgr_new,
        .put_node       = amdgpu_vram_mgr_del,
        .debug          = amdgpu_vram_mgr_debug
};