/*
 * Copyright (C) 2015 Etnaviv Project
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <linux/dma-fence-array.h>
#include <linux/reservation.h>
#include <linux/sync_file.h>
#include "etnaviv_cmdbuf.h"
#include "etnaviv_drv.h"
#include "etnaviv_gpu.h"
#include "etnaviv_gem.h"

/*
 * Cmdstream submission:
 */

#define BO_INVALID_FLAGS ~(ETNA_SUBMIT_BO_READ | ETNA_SUBMIT_BO_WRITE)
/* make sure these don't conflict w/ ETNAVIV_SUBMIT_BO_x */
#define BO_LOCKED   0x4000
#define BO_PINNED   0x2000

static struct etnaviv_gem_submit *submit_create(struct drm_device *dev,
                struct etnaviv_gpu *gpu, size_t nr)
{
        struct etnaviv_gem_submit *submit;
        size_t sz = size_vstruct(nr, sizeof(submit->bos[0]), sizeof(*submit));

        submit = kmalloc(sz, GFP_TEMPORARY | __GFP_NOWARN | __GFP_NORETRY);
        if (submit) {
                submit->dev = dev;
                submit->gpu = gpu;

                /* initially, until copy_from_user() and bo lookup succeeds: */
                submit->nr_bos = 0;
                submit->fence = NULL;

                ww_acquire_init(&submit->ticket, &reservation_ww_class);
        }

        return submit;
}

static int submit_lookup_objects(struct etnaviv_gem_submit *submit,
        struct drm_file *file, struct drm_etnaviv_gem_submit_bo *submit_bos,
        unsigned nr_bos)
{
        struct drm_etnaviv_gem_submit_bo *bo;
        unsigned i;
        int ret = 0;

        spin_lock(&file->table_lock);

        for (i = 0, bo = submit_bos; i < nr_bos; i++, bo++) {
                struct drm_gem_object *obj;

                if (bo->flags & BO_INVALID_FLAGS) {
                        DRM_ERROR("invalid flags: %x\n", bo->flags);
                        ret = -EINVAL;
                        goto out_unlock;
                }

                submit->bos[i].flags = bo->flags;

                /* normally use drm_gem_object_lookup(), but for bulk lookup
                 * all under single table_lock just hit object_idr directly:
                 */
                obj = idr_find(&file->object_idr, bo->handle);
                if (!obj) {
                        DRM_ERROR("invalid handle %u at index %u\n",
                                  bo->handle, i);
                        ret = -EINVAL;
                        goto out_unlock;
                }

                /*
                 * Take a refcount on the object. The file table lock
                 * prevents the object_idr's refcount on this being dropped.
                 */
                drm_gem_object_reference(obj);

                submit->bos[i].obj = to_etnaviv_bo(obj);
        }

out_unlock:
        submit->nr_bos = i;
        spin_unlock(&file->table_lock);

        return ret;
}

static void submit_unlock_object(struct etnaviv_gem_submit *submit, int i)
{
        if (submit->bos[i].flags & BO_LOCKED) {
                struct etnaviv_gem_object *etnaviv_obj = submit->bos[i].obj;

                ww_mutex_unlock(&etnaviv_obj->resv->lock);
                submit->bos[i].flags &= ~BO_LOCKED;
        }
}

static int submit_lock_objects(struct etnaviv_gem_submit *submit)
{
        int contended, slow_locked = -1, i, ret = 0;

retry:
        for (i = 0; i < submit->nr_bos; i++) {
                struct etnaviv_gem_object *etnaviv_obj = submit->bos[i].obj;

                if (slow_locked == i)
                        slow_locked = -1;

                contended = i;

                if (!(submit->bos[i].flags & BO_LOCKED)) {
                        ret = ww_mutex_lock_interruptible(&etnaviv_obj->resv->lock,
                                        &submit->ticket);
                        if (ret == -EALREADY)
                                DRM_ERROR("BO at index %u already on submit list\n",
                                          i);
                        if (ret)
                                goto fail;
                        submit->bos[i].flags |= BO_LOCKED;
                }
        }

        ww_acquire_done(&submit->ticket);

        return 0;

fail:
        for (; i >= 0; i--)
                submit_unlock_object(submit, i);

        if (slow_locked > 0)
                submit_unlock_object(submit, slow_locked);

        if (ret == -EDEADLK) {
                struct etnaviv_gem_object *etnaviv_obj;

                etnaviv_obj = submit->bos[contended].obj;

                /* we lost out in a seqno race, lock and retry.. */
                ret = ww_mutex_lock_slow_interruptible(&etnaviv_obj->resv->lock,
                                &submit->ticket);
                if (!ret) {
                        submit->bos[contended].flags |= BO_LOCKED;
                        slow_locked = contended;
                        goto retry;
                }
        }

        return ret;
}

static int submit_fence_sync(const struct etnaviv_gem_submit *submit)
{
        unsigned int context = submit->gpu->fence_context;
        int i, ret = 0;

        for (i = 0; i < submit->nr_bos; i++) {
                struct etnaviv_gem_object *etnaviv_obj = submit->bos[i].obj;
                bool write = submit->bos[i].flags & ETNA_SUBMIT_BO_WRITE;
                bool explicit = !!(submit->flags & ETNA_SUBMIT_NO_IMPLICIT);

                ret = etnaviv_gpu_fence_sync_obj(etnaviv_obj, context, write,
                                                 explicit);
                if (ret)
                        break;
        }

        return ret;
}

static void submit_unpin_objects(struct etnaviv_gem_submit *submit)
{
        int i;

        for (i = 0; i < submit->nr_bos; i++) {
                if (submit->bos[i].flags & BO_PINNED)
                        etnaviv_gem_mapping_unreference(submit->bos[i].mapping);

                submit->bos[i].mapping = NULL;
                submit->bos[i].flags &= ~BO_PINNED;
        }
}

static int submit_pin_objects(struct etnaviv_gem_submit *submit)
{
        int i, ret = 0;

        for (i = 0; i < submit->nr_bos; i++) {
                struct etnaviv_gem_object *etnaviv_obj = submit->bos[i].obj;
                struct etnaviv_vram_mapping *mapping;

                mapping = etnaviv_gem_mapping_get(&etnaviv_obj->base,
                                                  submit->gpu);
                if (IS_ERR(mapping)) {
                        ret = PTR_ERR(mapping);
                        break;
                }

                submit->bos[i].flags |= BO_PINNED;
                submit->bos[i].mapping = mapping;
        }

        return ret;
}

static int submit_bo(struct etnaviv_gem_submit *submit, u32 idx,
        struct etnaviv_gem_submit_bo **bo)
{
        if (idx >= submit->nr_bos) {
                DRM_ERROR("invalid buffer index: %u (out of %u)\n",
                                idx, submit->nr_bos);
                return -EINVAL;
        }

        *bo = &submit->bos[idx];

        return 0;
}

/* process the reloc's and patch up the cmdstream as needed: */
static int submit_reloc(struct etnaviv_gem_submit *submit, void *stream,
                u32 size, const struct drm_etnaviv_gem_submit_reloc *relocs,
                u32 nr_relocs)
{
        u32 i, last_offset = 0;
        u32 *ptr = stream;
        int ret;

        for (i = 0; i < nr_relocs; i++) {
                const struct drm_etnaviv_gem_submit_reloc *r = relocs + i;
                struct etnaviv_gem_submit_bo *bo;
                u32 off;

                if (unlikely(r->flags)) {
                        DRM_ERROR("invalid reloc flags\n");
                        return -EINVAL;
                }

                if (r->submit_offset % 4) {
                        DRM_ERROR("non-aligned reloc offset: %u\n",
                                  r->submit_offset);
                        return -EINVAL;
                }

                /* offset in dwords: */
                off = r->submit_offset / 4;

                if ((off >= size ) ||
                                (off < last_offset)) {
                        DRM_ERROR("invalid offset %u at reloc %u\n", off, i);
                        return -EINVAL;
                }

                ret = submit_bo(submit, r->reloc_idx, &bo);
                if (ret)
                        return ret;

                if (r->reloc_offset >= bo->obj->base.size - sizeof(*ptr)) {
                        DRM_ERROR("relocation %u outside object", i);
                        return -EINVAL;
                }

                ptr[off] = bo->mapping->iova + r->reloc_offset;

                last_offset = off;
        }

        return 0;
}

static void submit_cleanup(struct etnaviv_gem_submit *submit)
{
        unsigned i;

        for (i = 0; i < submit->nr_bos; i++) {
                struct etnaviv_gem_object *etnaviv_obj = submit->bos[i].obj;

                submit_unlock_object(submit, i);
                drm_gem_object_unreference_unlocked(&etnaviv_obj->base);
        }

        ww_acquire_fini(&submit->ticket);
        if (submit->fence)
                dma_fence_put(submit->fence);
        kfree(submit);
}

int etnaviv_ioctl_gem_submit(struct drm_device *dev, void *data,
                struct drm_file *file)
{
        struct etnaviv_drm_private *priv = dev->dev_private;
        struct drm_etnaviv_gem_submit *args = data;
        struct drm_etnaviv_gem_submit_reloc *relocs;
        struct drm_etnaviv_gem_submit_bo *bos;
        struct etnaviv_gem_submit *submit;
        struct etnaviv_cmdbuf *cmdbuf;
        struct etnaviv_gpu *gpu;
        struct dma_fence *in_fence = NULL;
        struct sync_file *sync_file = NULL;
        int out_fence_fd = -1;
        void *stream;
        int ret;

        if (args->pipe >= ETNA_MAX_PIPES)
                return -EINVAL;

        gpu = priv->gpu[args->pipe];
        if (!gpu)
                return -ENXIO;

        if (args->stream_size % 4) {
                DRM_ERROR("non-aligned cmdstream buffer size: %u\n",
                          args->stream_size);
                return -EINVAL;
        }

        if (args->exec_state != ETNA_PIPE_3D &&
            args->exec_state != ETNA_PIPE_2D &&
            args->exec_state != ETNA_PIPE_VG) {
                DRM_ERROR("invalid exec_state: 0x%x\n", args->exec_state);
                return -EINVAL;
        }

        if (args->flags & ~ETNA_SUBMIT_FLAGS) {
                DRM_ERROR("invalid flags: 0x%x\n", args->flags);
                return -EINVAL;
        }

        /*
         * Copy the command submission and bo array to kernel space in
         * one go, and do this outside of any locks.
         */
        bos = drm_malloc_ab(args->nr_bos, sizeof(*bos));
        relocs = drm_malloc_ab(args->nr_relocs, sizeof(*relocs));
        stream = drm_malloc_ab(1, args->stream_size);
        cmdbuf = etnaviv_cmdbuf_new(gpu->cmdbuf_suballoc,
                                    ALIGN(args->stream_size, 8) + 8,
                                    args->nr_bos);
        if (!bos || !relocs || !stream || !cmdbuf) {
                ret = -ENOMEM;
                goto err_submit_cmds;
        }

        cmdbuf->exec_state = args->exec_state;
        cmdbuf->ctx = file->driver_priv;

        ret = copy_from_user(bos, u64_to_user_ptr(args->bos),
                             args->nr_bos * sizeof(*bos));
        if (ret) {
                ret = -EFAULT;
                goto err_submit_cmds;
        }

        ret = copy_from_user(relocs, u64_to_user_ptr(args->relocs),
                             args->nr_relocs * sizeof(*relocs));
        if (ret) {
                ret = -EFAULT;
                goto err_submit_cmds;
        }

        ret = copy_from_user(stream, u64_to_user_ptr(args->stream),
                             args->stream_size);
        if (ret) {
                ret = -EFAULT;
                goto err_submit_cmds;
        }

        if (args->flags & ETNA_SUBMIT_FENCE_FD_OUT) {
                out_fence_fd = get_unused_fd_flags(O_CLOEXEC);
                if (out_fence_fd < 0) {
                        ret = out_fence_fd;
                        goto err_submit_cmds;
                }
        }

        submit = submit_create(dev, gpu, args->nr_bos);
        if (!submit) {
                ret = -ENOMEM;
                goto err_submit_cmds;
        }

        submit->flags = args->flags;

        ret = submit_lookup_objects(submit, file, bos, args->nr_bos);
        if (ret)
                goto err_submit_objects;

        ret = submit_lock_objects(submit);
        if (ret)
                goto err_submit_objects;

        if (!etnaviv_cmd_validate_one(gpu, stream, args->stream_size / 4,
                                      relocs, args->nr_relocs)) {
                ret = -EINVAL;
                goto err_submit_objects;
        }

        if (args->flags & ETNA_SUBMIT_FENCE_FD_IN) {
                in_fence = sync_file_get_fence(args->fence_fd);
                if (!in_fence) {
                        ret = -EINVAL;
                        goto err_submit_objects;
                }

                /*
                 * Wait if the fence is from a foreign context, or if the fence
                 * array contains any fence from a foreign context.
                 */
                if (!dma_fence_match_context(in_fence, gpu->fence_context)) {
                        ret = dma_fence_wait(in_fence, true);
                        if (ret)
                                goto err_submit_objects;
                }
        }

        ret = submit_fence_sync(submit);
        if (ret)
                goto err_submit_objects;

        ret = submit_pin_objects(submit);
        if (ret)
                goto out;

        ret = submit_reloc(submit, stream, args->stream_size / 4,
                           relocs, args->nr_relocs);
        if (ret)
                goto out;

        memcpy(cmdbuf->vaddr, stream, args->stream_size);
        cmdbuf->user_size = ALIGN(args->stream_size, 8);

        ret = etnaviv_gpu_submit(gpu, submit, cmdbuf);
        if (ret == 0)
                cmdbuf = NULL;

        if (args->flags & ETNA_SUBMIT_FENCE_FD_OUT) {
                /*
                 * This can be improved: ideally we want to allocate the sync
                 * file before kicking off the GPU job and just attach the
                 * fence to the sync file here, eliminating the ENOMEM
                 * possibility at this stage.
                 */
                sync_file = sync_file_create(submit->fence);
                if (!sync_file) {
                        ret = -ENOMEM;
                        goto out;
                }
                fd_install(out_fence_fd, sync_file->file);
        }

        args->fence_fd = out_fence_fd;
        args->fence = submit->fence->seqno;

out:
        submit_unpin_objects(submit);

        /*
         * If we're returning -EAGAIN, it may be due to the userptr code
         * wanting to run its workqueue outside of any locks. Flush our
         * workqueue to ensure that it is run in a timely manner.
         */
        if (ret == -EAGAIN)
                flush_workqueue(priv->wq);

err_submit_objects:
        if (in_fence)
                dma_fence_put(in_fence);
        submit_cleanup(submit);

err_submit_cmds:
        if (ret && (out_fence_fd >= 0))
                put_unused_fd(out_fence_fd);
        /* if we still own the cmdbuf */
        if (cmdbuf)
                etnaviv_cmdbuf_free(cmdbuf);
        if (stream)
                drm_free_large(stream);
        if (bos)
                drm_free_large(bos);
        if (relocs)
                drm_free_large(relocs);

        return ret;
}