/*
 * 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 "amdgpu.h"

struct amdgpu_gtt_mgr {
        struct drm_mm mm;
        spinlock_t lock;
        atomic64_t available;
};

struct amdgpu_gtt_node {
        struct drm_mm_node node;
        struct ttm_buffer_object *tbo;
};

/**
 * DOC: mem_info_gtt_total
 *
 * The amdgpu driver provides a sysfs API for reporting current total size of
 * the GTT.
 * The file mem_info_gtt_total is used for this, and returns the total size of
 * the GTT block, in bytes
 */
static ssize_t amdgpu_mem_info_gtt_total_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct drm_device *ddev = dev_get_drvdata(dev);
        struct amdgpu_device *adev = ddev->dev_private;

        return snprintf(buf, PAGE_SIZE, "%llu\n",
                        (adev->mman.bdev.man[TTM_PL_TT].size) * PAGE_SIZE);
}

/**
 * DOC: mem_info_gtt_used
 *
 * The amdgpu driver provides a sysfs API for reporting current total amount of
 * used GTT.
 * The file mem_info_gtt_used is used for this, and returns the current used
 * size of the GTT block, in bytes
 */
static ssize_t amdgpu_mem_info_gtt_used_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        struct drm_device *ddev = dev_get_drvdata(dev);
        struct amdgpu_device *adev = ddev->dev_private;

        return snprintf(buf, PAGE_SIZE, "%llu\n",
                        amdgpu_gtt_mgr_usage(&adev->mman.bdev.man[TTM_PL_TT]));
}

static DEVICE_ATTR(mem_info_gtt_total, S_IRUGO,
                   amdgpu_mem_info_gtt_total_show, NULL);
static DEVICE_ATTR(mem_info_gtt_used, S_IRUGO,
                   amdgpu_mem_info_gtt_used_show, NULL);

/**
 * 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_device *adev = amdgpu_ttm_adev(man->bdev);
        struct amdgpu_gtt_mgr *mgr;
        uint64_t start, size;
        int ret;

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

        start = AMDGPU_GTT_MAX_TRANSFER_SIZE * AMDGPU_GTT_NUM_TRANSFER_WINDOWS;
        size = (adev->gmc.gart_size >> PAGE_SHIFT) - start;
        drm_mm_init(&mgr->mm, start, size);
        spin_lock_init(&mgr->lock);
        atomic64_set(&mgr->available, p_size);
        man->priv = mgr;

        ret = device_create_file(adev->dev, &dev_attr_mem_info_gtt_total);
        if (ret) {
                DRM_ERROR("Failed to create device file mem_info_gtt_total\n");
                return ret;
        }
        ret = device_create_file(adev->dev, &dev_attr_mem_info_gtt_used);
        if (ret) {
                DRM_ERROR("Failed to create device file mem_info_gtt_used\n");
                return ret;
        }

        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_device *adev = amdgpu_ttm_adev(man->bdev);
        struct amdgpu_gtt_mgr *mgr = man->priv;
        spin_lock(&mgr->lock);
        drm_mm_takedown(&mgr->mm);
        spin_unlock(&mgr->lock);
        kfree(mgr);
        man->priv = NULL;

        device_remove_file(adev->dev, &dev_attr_mem_info_gtt_total);
        device_remove_file(adev->dev, &dev_attr_mem_info_gtt_used);

        return 0;
}

/**
 * amdgpu_gtt_mgr_has_gart_addr - Check if mem has address space
 *
 * @mem: the mem object to check
 *
 * Check if a mem object has already address space allocated.
 */
bool amdgpu_gtt_mgr_has_gart_addr(struct ttm_mem_reg *mem)
{
        struct amdgpu_gtt_node *node = mem->mm_node;

        return (node->node.start != AMDGPU_BO_INVALID_OFFSET);
}

/**
 * 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.
 */
static 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_device *adev = amdgpu_ttm_adev(man->bdev);
        struct amdgpu_gtt_mgr *mgr = man->priv;
        struct amdgpu_gtt_node *node = mem->mm_node;
        enum drm_mm_insert_mode mode;
        unsigned long fpfn, lpfn;
        int r;

        if (amdgpu_gtt_mgr_has_gart_addr(mem))
                return 0;

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

        if (place && place->lpfn)
                lpfn = place->lpfn;
        else
                lpfn = adev->gart.num_cpu_pages;

        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->node, mem->num_pages,
                                        mem->page_alignment, 0, fpfn, lpfn,
                                        mode);
        spin_unlock(&mgr->lock);

        if (!r)
                mem->start = node->node.start;

        return r;
}

/**
 * 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 amdgpu_gtt_node *node;
        int r;

        spin_lock(&mgr->lock);
        if ((&tbo->mem == mem || tbo->mem.mem_type != TTM_PL_TT) &&
            atomic64_read(&mgr->available) < mem->num_pages) {
                spin_unlock(&mgr->lock);
                return 0;
        }
        atomic64_sub(mem->num_pages, &mgr->available);
        spin_unlock(&mgr->lock);

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

        node->node.start = AMDGPU_BO_INVALID_OFFSET;
        node->node.size = mem->num_pages;
        node->tbo = tbo;
        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->node.start;
        }

        return 0;
err_out:
        atomic64_add(mem->num_pages, &mgr->available);

        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 amdgpu_gtt_node *node = mem->mm_node;

        if (!node)
                return;

        spin_lock(&mgr->lock);
        if (node->node.start != AMDGPU_BO_INVALID_OFFSET)
                drm_mm_remove_node(&node->node);
        spin_unlock(&mgr->lock);
        atomic64_add(mem->num_pages, &mgr->available);

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

/**
 * amdgpu_gtt_mgr_usage - return usage of GTT domain
 *
 * @man: TTM memory type manager
 *
 * Return how many bytes are used in the GTT domain
 */
uint64_t amdgpu_gtt_mgr_usage(struct ttm_mem_type_manager *man)
{
        struct amdgpu_gtt_mgr *mgr = man->priv;
        s64 result = man->size - atomic64_read(&mgr->available);

        return (result > 0 ? result : 0) * PAGE_SIZE;
}

int amdgpu_gtt_mgr_recover(struct ttm_mem_type_manager *man)
{
        struct amdgpu_gtt_mgr *mgr = man->priv;
        struct amdgpu_gtt_node *node;
        struct drm_mm_node *mm_node;
        int r = 0;

        spin_lock(&mgr->lock);
        drm_mm_for_each_node(mm_node, &mgr->mm) {
                node = container_of(mm_node, struct amdgpu_gtt_node, node);
                r = amdgpu_ttm_recover_gart(node->tbo);
                if (r)
                        break;
        }
        spin_unlock(&mgr->lock);

        return r;
}

/**
 * amdgpu_gtt_mgr_debug - dump VRAM table
 *
 * @man: TTM memory type manager
 * @printer: DRM printer to use
 *
 * Dump the table content using printk.
 */
static void amdgpu_gtt_mgr_debug(struct ttm_mem_type_manager *man,
                                 struct drm_printer *printer)
{
        struct amdgpu_gtt_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, gtt available:%lld pages, usage:%lluMB\n",
                   man->size, (u64)atomic64_read(&mgr->available),
                   amdgpu_gtt_mgr_usage(man) >> 20);
}

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
};