/*
 * Copyright (C) 2013 Red Hat
 * Author: Rob Clark <robdclark@gmail.com>
 *
 * 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 "msm_drv.h"
#include "msm_gpu.h"
#include "msm_gem.h"

/*
 * Cmdstream submission:
 */

/* make sure these don't conflict w/ MSM_SUBMIT_BO_x */
#define BO_VALID    0x8000
#define BO_LOCKED   0x4000
#define BO_PINNED   0x2000

static inline void __user *to_user_ptr(u64 address)
{
        return (void __user *)(uintptr_t)address;
}

static struct msm_gem_submit *submit_create(struct drm_device *dev,
                struct msm_gpu *gpu, int nr)
{
        struct msm_gem_submit *submit;
        int sz = sizeof(*submit) + (nr * sizeof(submit->bos[0]));

        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->nr_cmds = 0;

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

        return submit;
}

static int submit_lookup_objects(struct msm_gem_submit *submit,
                struct drm_msm_gem_submit *args, struct drm_file *file)
{
        unsigned i;
        int ret = 0;

        spin_lock(&file->table_lock);

        for (i = 0; i < args->nr_bos; i++) {
                struct drm_msm_gem_submit_bo submit_bo;
                struct drm_gem_object *obj;
                struct msm_gem_object *msm_obj;
                void __user *userptr =
                        to_user_ptr(args->bos + (i * sizeof(submit_bo)));

                ret = copy_from_user(&submit_bo, userptr, sizeof(submit_bo));
                if (ret) {
                        ret = -EFAULT;
                        goto out_unlock;
                }

                if (submit_bo.flags & ~MSM_SUBMIT_BO_FLAGS) {
                        DRM_ERROR("invalid flags: %x\n", submit_bo.flags);
                        ret = -EINVAL;
                        goto out_unlock;
                }

                submit->bos[i].flags = submit_bo.flags;
                /* in validate_objects() we figure out if this is true: */
                submit->bos[i].iova  = submit_bo.presumed;

                /* 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, submit_bo.handle);
                if (!obj) {
                        DRM_ERROR("invalid handle %u at index %u\n", submit_bo.handle, i);
                        ret = -EINVAL;
                        goto out_unlock;
                }

                msm_obj = to_msm_bo(obj);

                if (!list_empty(&msm_obj->submit_entry)) {
                        DRM_ERROR("handle %u at index %u already on submit list\n",
                                        submit_bo.handle, i);
                        ret = -EINVAL;
                        goto out_unlock;
                }

                drm_gem_object_reference(obj);

                submit->bos[i].obj = msm_obj;

                list_add_tail(&msm_obj->submit_entry, &submit->bo_list);
        }

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

        return ret;
}

static void submit_unlock_unpin_bo(struct msm_gem_submit *submit, int i)
{
        struct msm_gem_object *msm_obj = submit->bos[i].obj;

        if (submit->bos[i].flags & BO_PINNED)
                msm_gem_put_iova(&msm_obj->base, submit->gpu->id);

        if (submit->bos[i].flags & BO_LOCKED)
                ww_mutex_unlock(&msm_obj->resv->lock);

        if (!(submit->bos[i].flags & BO_VALID))
                submit->bos[i].iova = 0;

        submit->bos[i].flags &= ~(BO_LOCKED | BO_PINNED);
}

/* This is where we make sure all the bo's are reserved and pin'd: */
static int submit_validate_objects(struct msm_gem_submit *submit)
{
        int contended, slow_locked = -1, i, ret = 0;

retry:
        submit->valid = true;

        for (i = 0; i < submit->nr_bos; i++) {
                struct msm_gem_object *msm_obj = submit->bos[i].obj;
                uint32_t iova;

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

                contended = i;

                if (!(submit->bos[i].flags & BO_LOCKED)) {
                        ret = ww_mutex_lock_interruptible(&msm_obj->resv->lock,
                                        &submit->ticket);
                        if (ret)
                                goto fail;
                        submit->bos[i].flags |= BO_LOCKED;
                }


                /* if locking succeeded, pin bo: */
                ret = msm_gem_get_iova_locked(&msm_obj->base,
                                submit->gpu->id, &iova);

                /* this would break the logic in the fail path.. there is no
                 * reason for this to happen, but just to be on the safe side
                 * let's notice if this starts happening in the future:
                 */
                WARN_ON(ret == -EDEADLK);

                if (ret)
                        goto fail;

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

                if (iova == submit->bos[i].iova) {
                        submit->bos[i].flags |= BO_VALID;
                } else {
                        submit->bos[i].iova = iova;
                        submit->bos[i].flags &= ~BO_VALID;
                        submit->valid = false;
                }
        }

        ww_acquire_done(&submit->ticket);

        return 0;

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

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

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

        return ret;
}

static int submit_bo(struct msm_gem_submit *submit, uint32_t idx,
                struct msm_gem_object **obj, uint32_t *iova, bool *valid)
{
        if (idx >= submit->nr_bos) {
                DRM_ERROR("invalid buffer index: %u (out of %u)\n",
                                idx, submit->nr_bos);
                return -EINVAL;
        }

        if (obj)
                *obj = submit->bos[idx].obj;
        if (iova)
                *iova = submit->bos[idx].iova;
        if (valid)
                *valid = !!(submit->bos[idx].flags & BO_VALID);

        return 0;
}

/* process the reloc's and patch up the cmdstream as needed: */
static int submit_reloc(struct msm_gem_submit *submit, struct msm_gem_object *obj,
                uint32_t offset, uint32_t nr_relocs, uint64_t relocs)
{
        uint32_t i, last_offset = 0;
        uint32_t *ptr;
        int ret;

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

        /* For now, just map the entire thing.  Eventually we probably
         * to do it page-by-page, w/ kmap() if not vmap()d..
         */
        ptr = msm_gem_vaddr_locked(&obj->base);

        if (IS_ERR(ptr)) {
                ret = PTR_ERR(ptr);
                DBG("failed to map: %d", ret);
                return ret;
        }

        for (i = 0; i < nr_relocs; i++) {
                struct drm_msm_gem_submit_reloc submit_reloc;
                void __user *userptr =
                        to_user_ptr(relocs + (i * sizeof(submit_reloc)));
                uint32_t iova, off;
                bool valid;

                ret = copy_from_user(&submit_reloc, userptr, sizeof(submit_reloc));
                if (ret)
                        return -EFAULT;

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

                /* offset in dwords: */
                off = submit_reloc.submit_offset / 4;

                if ((off >= (obj->base.size / 4)) ||
                                (off < last_offset)) {
                        DRM_ERROR("invalid offset %u at reloc %u\n", off, i);
                        return -EINVAL;
                }

                ret = submit_bo(submit, submit_reloc.reloc_idx, NULL, &iova, &valid);
                if (ret)
                        return ret;

                if (valid)
                        continue;

                iova += submit_reloc.reloc_offset;

                if (submit_reloc.shift < 0)
                        iova >>= -submit_reloc.shift;
                else
                        iova <<= submit_reloc.shift;

                ptr[off] = iova | submit_reloc.or;

                last_offset = off;
        }

        return 0;
}

static void submit_cleanup(struct msm_gem_submit *submit, bool fail)
{
        unsigned i;

        for (i = 0; i < submit->nr_bos; i++) {
                struct msm_gem_object *msm_obj = submit->bos[i].obj;
                submit_unlock_unpin_bo(submit, i);
                list_del_init(&msm_obj->submit_entry);
                drm_gem_object_unreference(&msm_obj->base);
        }

        ww_acquire_fini(&submit->ticket);
}

int msm_ioctl_gem_submit(struct drm_device *dev, void *data,
                struct drm_file *file)
{
        struct msm_drm_private *priv = dev->dev_private;
        struct drm_msm_gem_submit *args = data;
        struct msm_file_private *ctx = file->driver_priv;
        struct msm_gem_submit *submit;
        struct msm_gpu *gpu;
        unsigned i;
        int ret;

        /* for now, we just have 3d pipe.. eventually this would need to
         * be more clever to dispatch to appropriate gpu module:
         */
        if (args->pipe != MSM_PIPE_3D0)
                return -EINVAL;

        gpu = priv->gpu;

        if (args->nr_cmds > MAX_CMDS)
                return -EINVAL;

        mutex_lock(&dev->struct_mutex);

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

        ret = submit_lookup_objects(submit, args, file);
        if (ret)
                goto out;

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

        for (i = 0; i < args->nr_cmds; i++) {
                struct drm_msm_gem_submit_cmd submit_cmd;
                void __user *userptr =
                        to_user_ptr(args->cmds + (i * sizeof(submit_cmd)));
                struct msm_gem_object *msm_obj;
                uint32_t iova;

                ret = copy_from_user(&submit_cmd, userptr, sizeof(submit_cmd));
                if (ret) {
                        ret = -EFAULT;
                        goto out;
                }

                /* validate input from userspace: */
                switch (submit_cmd.type) {
                case MSM_SUBMIT_CMD_BUF:
                case MSM_SUBMIT_CMD_IB_TARGET_BUF:
                case MSM_SUBMIT_CMD_CTX_RESTORE_BUF:
                        break;
                default:
                        DRM_ERROR("invalid type: %08x\n", submit_cmd.type);
                        ret = -EINVAL;
                        goto out;
                }

                ret = submit_bo(submit, submit_cmd.submit_idx,
                                &msm_obj, &iova, NULL);
                if (ret)
                        goto out;

                if (submit_cmd.size % 4) {
                        DRM_ERROR("non-aligned cmdstream buffer size: %u\n",
                                        submit_cmd.size);
                        ret = -EINVAL;
                        goto out;
                }

                if ((submit_cmd.size + submit_cmd.submit_offset) >=
                                msm_obj->base.size) {
                        DRM_ERROR("invalid cmdstream size: %u\n", submit_cmd.size);
                        ret = -EINVAL;
                        goto out;
                }

                submit->cmd[i].type = submit_cmd.type;
                submit->cmd[i].size = submit_cmd.size / 4;
                submit->cmd[i].iova = iova + submit_cmd.submit_offset;
                submit->cmd[i].idx  = submit_cmd.submit_idx;

                if (submit->valid)
                        continue;

                ret = submit_reloc(submit, msm_obj, submit_cmd.submit_offset,
                                submit_cmd.nr_relocs, submit_cmd.relocs);
                if (ret)
                        goto out;
        }

        submit->nr_cmds = i;

        ret = msm_gpu_submit(gpu, submit, ctx);

        args->fence = submit->fence;

out:
        if (submit)
                submit_cleanup(submit, !!ret);
        mutex_unlock(&dev->struct_mutex);
        return ret;
}