/*
 * Copyright 2011 Red Hat Inc.
 * 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 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.
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 *
 */
/*
 * Authors:
 *    Jerome Glisse <glisse@freedesktop.org>
 */
/* Algorithm:
 *
 * We store the last allocated bo in "hole", we always try to allocate
 * after the last allocated bo. Principle is that in a linear GPU ring
 * progression was is after last is the oldest bo we allocated and thus
 * the first one that should no longer be in use by the GPU.
 *
 * If it's not the case we skip over the bo after last to the closest
 * done bo if such one exist. If none exist and we are not asked to
 * block we report failure to allocate.
 *
 * If we are asked to block we wait on all the oldest fence of all
 * rings. We just wait for any of those fence to complete.
 */
#include <drm/drmP.h>
#include "radeon.h"

static void radeon_sa_bo_remove_locked(struct radeon_sa_bo *sa_bo);
static void radeon_sa_bo_try_free(struct radeon_sa_manager *sa_manager);

int radeon_sa_bo_manager_init(struct radeon_device *rdev,
                              struct radeon_sa_manager *sa_manager,
                              unsigned size, u32 align, u32 domain, u32 flags)
{
        int i, r;

        init_waitqueue_head(&sa_manager->wq);
        sa_manager->bo = NULL;
        sa_manager->size = size;
        sa_manager->domain = domain;
        sa_manager->align = align;
        sa_manager->hole = &sa_manager->olist;
        INIT_LIST_HEAD(&sa_manager->olist);
        for (i = 0; i < RADEON_NUM_RINGS; ++i) {
                INIT_LIST_HEAD(&sa_manager->flist[i]);
        }

        r = radeon_bo_create(rdev, size, align, true,
                             domain, flags, NULL, NULL, &sa_manager->bo);
        if (r) {
                dev_err(rdev->dev, "(%d) failed to allocate bo for manager\n", r);
                return r;
        }

        return r;
}

void radeon_sa_bo_manager_fini(struct radeon_device *rdev,
                               struct radeon_sa_manager *sa_manager)
{
        struct radeon_sa_bo *sa_bo, *tmp;

        if (!list_empty(&sa_manager->olist)) {
                sa_manager->hole = &sa_manager->olist,
                radeon_sa_bo_try_free(sa_manager);
                if (!list_empty(&sa_manager->olist)) {
                        dev_err(rdev->dev, "sa_manager is not empty, clearing anyway\n");
                }
        }
        list_for_each_entry_safe(sa_bo, tmp, &sa_manager->olist, olist) {
                radeon_sa_bo_remove_locked(sa_bo);
        }
        radeon_bo_unref(&sa_manager->bo);
        sa_manager->size = 0;
}

int radeon_sa_bo_manager_start(struct radeon_device *rdev,
                               struct radeon_sa_manager *sa_manager)
{
        int r;

        if (sa_manager->bo == NULL) {
                dev_err(rdev->dev, "no bo for sa manager\n");
                return -EINVAL;
        }

        /* map the buffer */
        r = radeon_bo_reserve(sa_manager->bo, false);
        if (r) {
                dev_err(rdev->dev, "(%d) failed to reserve manager bo\n", r);
                return r;
        }
        r = radeon_bo_pin(sa_manager->bo, sa_manager->domain, &sa_manager->gpu_addr);
        if (r) {
                radeon_bo_unreserve(sa_manager->bo);
                dev_err(rdev->dev, "(%d) failed to pin manager bo\n", r);
                return r;
        }
        r = radeon_bo_kmap(sa_manager->bo, &sa_manager->cpu_ptr);
        radeon_bo_unreserve(sa_manager->bo);
        return r;
}

int radeon_sa_bo_manager_suspend(struct radeon_device *rdev,
                                 struct radeon_sa_manager *sa_manager)
{
        int r;

        if (sa_manager->bo == NULL) {
                dev_err(rdev->dev, "no bo for sa manager\n");
                return -EINVAL;
        }

        r = radeon_bo_reserve(sa_manager->bo, false);
        if (!r) {
                radeon_bo_kunmap(sa_manager->bo);
                radeon_bo_unpin(sa_manager->bo);
                radeon_bo_unreserve(sa_manager->bo);
        }
        return r;
}

static void radeon_sa_bo_remove_locked(struct radeon_sa_bo *sa_bo)
{
        struct radeon_sa_manager *sa_manager = sa_bo->manager;
        if (sa_manager->hole == &sa_bo->olist) {
                sa_manager->hole = sa_bo->olist.prev;
        }
        list_del_init(&sa_bo->olist);
        list_del_init(&sa_bo->flist);
        radeon_fence_unref(&sa_bo->fence);
        kfree(sa_bo);
}

static void radeon_sa_bo_try_free(struct radeon_sa_manager *sa_manager)
{
        struct radeon_sa_bo *sa_bo, *tmp;

        if (sa_manager->hole->next == &sa_manager->olist)
                return;

        sa_bo = list_entry(sa_manager->hole->next, struct radeon_sa_bo, olist);
        list_for_each_entry_safe_from(sa_bo, tmp, &sa_manager->olist, olist) {
                if (sa_bo->fence == NULL || !radeon_fence_signaled(sa_bo->fence)) {
                        return;
                }
                radeon_sa_bo_remove_locked(sa_bo);
        }
}

static inline unsigned radeon_sa_bo_hole_soffset(struct radeon_sa_manager *sa_manager)
{
        struct list_head *hole = sa_manager->hole;

        if (hole != &sa_manager->olist) {
                return list_entry(hole, struct radeon_sa_bo, olist)->eoffset;
        }
        return 0;
}

static inline unsigned radeon_sa_bo_hole_eoffset(struct radeon_sa_manager *sa_manager)
{
        struct list_head *hole = sa_manager->hole;

        if (hole->next != &sa_manager->olist) {
                return list_entry(hole->next, struct radeon_sa_bo, olist)->soffset;
        }
        return sa_manager->size;
}

static bool radeon_sa_bo_try_alloc(struct radeon_sa_manager *sa_manager,
                                   struct radeon_sa_bo *sa_bo,
                                   unsigned size, unsigned align)
{
        unsigned soffset, eoffset, wasted;

        soffset = radeon_sa_bo_hole_soffset(sa_manager);
        eoffset = radeon_sa_bo_hole_eoffset(sa_manager);
        wasted = (align - (soffset % align)) % align;

        if ((eoffset - soffset) >= (size + wasted)) {
                soffset += wasted;

                sa_bo->manager = sa_manager;
                sa_bo->soffset = soffset;
                sa_bo->eoffset = soffset + size;
                list_add(&sa_bo->olist, sa_manager->hole);
                INIT_LIST_HEAD(&sa_bo->flist);
                sa_manager->hole = &sa_bo->olist;
                return true;
        }
        return false;
}

/**
 * radeon_sa_event - Check if we can stop waiting
 *
 * @sa_manager: pointer to the sa_manager
 * @size: number of bytes we want to allocate
 * @align: alignment we need to match
 *
 * Check if either there is a fence we can wait for or
 * enough free memory to satisfy the allocation directly
 */
static bool radeon_sa_event(struct radeon_sa_manager *sa_manager,
                            unsigned size, unsigned align)
{
        unsigned soffset, eoffset, wasted;
        int i;

        for (i = 0; i < RADEON_NUM_RINGS; ++i) {
                if (!list_empty(&sa_manager->flist[i])) {
                        return true;
                }
        }

        soffset = radeon_sa_bo_hole_soffset(sa_manager);
        eoffset = radeon_sa_bo_hole_eoffset(sa_manager);
        wasted = (align - (soffset % align)) % align;

        if ((eoffset - soffset) >= (size + wasted)) {
                return true;
        }

        return false;
}

static bool radeon_sa_bo_next_hole(struct radeon_sa_manager *sa_manager,
                                   struct radeon_fence **fences,
                                   unsigned *tries)
{
        struct radeon_sa_bo *best_bo = NULL;
        unsigned i, soffset, best, tmp;

        /* if hole points to the end of the buffer */
        if (sa_manager->hole->next == &sa_manager->olist) {
                /* try again with its beginning */
                sa_manager->hole = &sa_manager->olist;
                return true;
        }

        soffset = radeon_sa_bo_hole_soffset(sa_manager);
        /* to handle wrap around we add sa_manager->size */
        best = sa_manager->size * 2;
        /* go over all fence list and try to find the closest sa_bo
         * of the current last
         */
        for (i = 0; i < RADEON_NUM_RINGS; ++i) {
                struct radeon_sa_bo *sa_bo;

                if (list_empty(&sa_manager->flist[i])) {
                        continue;
                }

                sa_bo = list_first_entry(&sa_manager->flist[i],
                                         struct radeon_sa_bo, flist);

                if (!radeon_fence_signaled(sa_bo->fence)) {
                        fences[i] = sa_bo->fence;
                        continue;
                }

                /* limit the number of tries each ring gets */
                if (tries[i] > 2) {
                        continue;
                }

                tmp = sa_bo->soffset;
                if (tmp < soffset) {
                        /* wrap around, pretend it's after */
                        tmp += sa_manager->size;
                }
                tmp -= soffset;
                if (tmp < best) {
                        /* this sa bo is the closest one */
                        best = tmp;
                        best_bo = sa_bo;
                }
        }

        if (best_bo) {
                ++tries[best_bo->fence->ring];
                sa_manager->hole = best_bo->olist.prev;

                /* we knew that this one is signaled,
                   so it's save to remote it */
                radeon_sa_bo_remove_locked(best_bo);
                return true;
        }
        return false;
}

int radeon_sa_bo_new(struct radeon_device *rdev,
                     struct radeon_sa_manager *sa_manager,
                     struct radeon_sa_bo **sa_bo,
                     unsigned size, unsigned align)
{
        struct radeon_fence *fences[RADEON_NUM_RINGS];
        unsigned tries[RADEON_NUM_RINGS];
        int i, r;

        BUG_ON(align > sa_manager->align);
        BUG_ON(size > sa_manager->size);

        *sa_bo = kmalloc(sizeof(struct radeon_sa_bo), M_DRM, GFP_KERNEL);
        if ((*sa_bo) == NULL) {
                return -ENOMEM;
        }
        (*sa_bo)->manager = sa_manager;
        (*sa_bo)->fence = NULL;
        INIT_LIST_HEAD(&(*sa_bo)->olist);
        INIT_LIST_HEAD(&(*sa_bo)->flist);

        lockmgr(&sa_manager->wq.lock, LK_EXCLUSIVE);
        do {
                for (i = 0; i < RADEON_NUM_RINGS; ++i) {
                        fences[i] = NULL;
                        tries[i] = 0;
                }

                do {
                        radeon_sa_bo_try_free(sa_manager);

                        if (radeon_sa_bo_try_alloc(sa_manager, *sa_bo,
                                                   size, align)) {
                                lockmgr(&sa_manager->wq.lock, LK_RELEASE);
                                return 0;
                        }

                        /* see if we can skip over some allocations */
                } while (radeon_sa_bo_next_hole(sa_manager, fences, tries));

                for (i = 0; i < RADEON_NUM_RINGS; ++i)
                        radeon_fence_ref(fences[i]);

                lockmgr(&sa_manager->wq.lock, LK_RELEASE);
                r = radeon_fence_wait_any(rdev, fences, false);
                for (i = 0; i < RADEON_NUM_RINGS; ++i)
                        radeon_fence_unref(&fences[i]);
                lockmgr(&sa_manager->wq.lock, LK_EXCLUSIVE);
                /* if we have nothing to wait for block */
                if (r == -ENOENT) {
                        r = wait_event_interruptible_locked(
                                sa_manager->wq, 
                                radeon_sa_event(sa_manager, size, align)
                        );
                }

        } while (!r);

        lockmgr(&sa_manager->wq.lock, LK_RELEASE);
        kfree(*sa_bo);
        *sa_bo = NULL;
        return r;
}

void radeon_sa_bo_free(struct radeon_device *rdev, struct radeon_sa_bo **sa_bo,
                       struct radeon_fence *fence)
{
        struct radeon_sa_manager *sa_manager;

        if (sa_bo == NULL || *sa_bo == NULL) {
                return;
        }

        sa_manager = (*sa_bo)->manager;
        lockmgr(&sa_manager->wq.lock, LK_EXCLUSIVE);
        if (fence && !radeon_fence_signaled(fence)) {
                (*sa_bo)->fence = radeon_fence_ref(fence);
                list_add_tail(&(*sa_bo)->flist,
                              &sa_manager->flist[fence->ring]);
        } else {
                radeon_sa_bo_remove_locked(*sa_bo);
        }
        wake_up_all_locked(&sa_manager->wq);
        lockmgr(&sa_manager->wq.lock, LK_RELEASE);
        *sa_bo = NULL;
}

#if defined(CONFIG_DEBUG_FS)
void radeon_sa_bo_dump_debug_info(struct radeon_sa_manager *sa_manager,
                                  struct seq_file *m)
{
        struct radeon_sa_bo *i;

        lockmgr(&sa_manager->wq.lock, LK_EXCLUSIVE);
        list_for_each_entry(i, &sa_manager->olist, olist) {
                uint64_t soffset = i->soffset + sa_manager->gpu_addr;
                uint64_t eoffset = i->eoffset + sa_manager->gpu_addr;
                if (&i->olist == sa_manager->hole) {
                        seq_printf(m, ">");
                } else {
                        seq_printf(m, " ");
                }
                seq_printf(m, "[0x%010llx 0x%010llx] size %8lld",
                           soffset, eoffset, eoffset - soffset);
                if (i->fence) {
                        seq_printf(m, " protected by 0x%016llx on ring %d",
                                   i->fence->seq, i->fence->ring);
                }
                seq_printf(m, "\n");
        }
        lockmgr(&sa_manager->wq.lock, LK_RELEASE);
}
#endif