/*
 * 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 <linux/sync_file.h>

#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   /* is current addr in cmdstream correct/valid? */
#define BO_LOCKED   0x4000
#define BO_PINNED   0x2000

static struct msm_gem_submit *submit_create(struct drm_device *dev,
                struct msm_gpu *gpu, struct msm_gpu_submitqueue *queue,
                uint32_t nr_bos, uint32_t nr_cmds)
{
        struct msm_gem_submit *submit;
        uint64_t sz = sizeof(*submit) + ((u64)nr_bos * sizeof(submit->bos[0])) +
                ((u64)nr_cmds * sizeof(submit->cmd[0]));

        if (sz > SIZE_MAX)
                return NULL;

        submit = kmalloc(sz, GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY);
        if (!submit)
                return NULL;

        submit->dev = dev;
        submit->gpu = gpu;
        submit->fence = NULL;
        submit->pid = get_pid(task_pid(current));
        submit->cmd = (void *)&submit->bos[nr_bos];
        submit->queue = queue;
        submit->ring = gpu->rb[queue->prio];

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

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

        return submit;
}

void msm_gem_submit_free(struct msm_gem_submit *submit)
{
        dma_fence_put(submit->fence);
        list_del(&submit->node);
        put_pid(submit->pid);
        msm_submitqueue_put(submit->queue);

        kfree(submit);
}

static inline unsigned long __must_check
copy_from_user_inatomic(void *to, const void __user *from, unsigned long n)
{
        if (access_ok(VERIFY_READ, from, n))
                return __copy_from_user_inatomic(to, from, n);
        return -EFAULT;
}

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);
        pagefault_disable();

        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 =
                        u64_to_user_ptr(args->bos + (i * sizeof(submit_bo)));

                /* make sure we don't have garbage flags, in case we hit
                 * error path before flags is initialized:
                 */
                submit->bos[i].flags = 0;

                if (copy_from_user_inatomic(&submit_bo, userptr, sizeof(submit_bo))) {
                        pagefault_enable();
                        spin_unlock(&file->table_lock);
                        if (copy_from_user(&submit_bo, userptr, sizeof(submit_bo))) {
                                ret = -EFAULT;
                                goto out;
                        }
                        spin_lock(&file->table_lock);
                        pagefault_disable();
                }

                if ((submit_bo.flags & ~MSM_SUBMIT_BO_FLAGS) ||
                        !(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:
        pagefault_enable();
        spin_unlock(&file->table_lock);

out:
        submit->nr_bos = i;

        return ret;
}

static void submit_unlock_unpin_bo(struct msm_gem_submit *submit,
                int i, bool backoff)
{
        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->aspace);

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

        if (backoff && !(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_lock_objects(struct msm_gem_submit *submit)
{
        int contended, slow_locked = -1, i, ret = 0;

retry:
        for (i = 0; i < submit->nr_bos; i++) {
                struct msm_gem_object *msm_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(&msm_obj->resv->lock,
                                        &submit->ticket);
                        if (ret)
                                goto fail;
                        submit->bos[i].flags |= BO_LOCKED;
                }
        }

        ww_acquire_done(&submit->ticket);

        return 0;

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

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

        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_fence_sync(struct msm_gem_submit *submit, bool no_implicit)
{
        int i, ret = 0;

        for (i = 0; i < submit->nr_bos; i++) {
                struct msm_gem_object *msm_obj = submit->bos[i].obj;
                bool write = submit->bos[i].flags & MSM_SUBMIT_BO_WRITE;

                if (!write) {
                        /* NOTE: _reserve_shared() must happen before
                         * _add_shared_fence(), which makes this a slightly
                         * strange place to call it.  OTOH this is a
                         * convenient can-fail point to hook it in.
                         */
                        ret = reservation_object_reserve_shared(msm_obj->resv);
                        if (ret)
                                return ret;
                }

                if (no_implicit)
                        continue;

                ret = msm_gem_sync_object(&msm_obj->base, submit->ring->fctx,
                        write);
                if (ret)
                        break;
        }

        return ret;
}

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

        submit->valid = true;

        for (i = 0; i < submit->nr_bos; i++) {
                struct msm_gem_object *msm_obj = submit->bos[i].obj;
                uint64_t iova;

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

                if (ret)
                        break;

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

                if (iova == submit->bos[i].iova) {
                        submit->bos[i].flags |= BO_VALID;
                } else {
                        submit->bos[i].iova = iova;
                        /* iova changed, so address in cmdstream is not valid: */
                        submit->bos[i].flags &= ~BO_VALID;
                        submit->valid = false;
                }
        }

        return ret;
}

static int submit_bo(struct msm_gem_submit *submit, uint32_t idx,
                struct msm_gem_object **obj, uint64_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 = 0;

        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_get_vaddr(&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 =
                        u64_to_user_ptr(relocs + (i * sizeof(submit_reloc)));
                uint32_t off;
                uint64_t iova;
                bool valid;

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

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

                /* 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);
                        ret = -EINVAL;
                        goto out;
                }

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

                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;
        }

out:
        msm_gem_put_vaddr(&obj->base);

        return ret;
}

static void submit_cleanup(struct msm_gem_submit *submit)
{
        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, false);
                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 = priv->gpu;
        struct dma_fence *in_fence = NULL;
        struct sync_file *sync_file = NULL;
        struct msm_gpu_submitqueue *queue;
        struct msm_ringbuffer *ring;
        int out_fence_fd = -1;
        unsigned i;
        int ret;

        if (!gpu)
                return -ENXIO;

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

        if (MSM_PIPE_FLAGS(args->flags) & ~MSM_SUBMIT_FLAGS)
                return -EINVAL;

        if (args->flags & MSM_SUBMIT_SUDO) {
                if (!IS_ENABLED(CONFIG_DRM_MSM_GPU_SUDO) ||
                    !capable(CAP_SYS_RAWIO))
                        return -EINVAL;
        }

        queue = msm_submitqueue_get(ctx, args->queueid);
        if (!queue)
                return -ENOENT;

        ring = gpu->rb[queue->prio];

        if (args->flags & MSM_SUBMIT_FENCE_FD_IN) {
                in_fence = sync_file_get_fence(args->fence_fd);

                if (!in_fence)
                        return -EINVAL;

                /*
                 * 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, ring->fctx->context)) {
                        ret = dma_fence_wait(in_fence, true);
                        if (ret)
                                return ret;
                }
        }

        ret = mutex_lock_interruptible(&dev->struct_mutex);
        if (ret)
                return ret;

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

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

        if (args->flags & MSM_SUBMIT_SUDO)
                submit->in_rb = true;

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

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

        ret = submit_fence_sync(submit, !!(args->flags & MSM_SUBMIT_NO_IMPLICIT));
        if (ret)
                goto out;

        ret = submit_pin_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 =
                        u64_to_user_ptr(args->cmds + (i * sizeof(submit_cmd)));
                struct msm_gem_object *msm_obj;
                uint64_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.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;

        submit->fence = msm_fence_alloc(ring->fctx);
        if (IS_ERR(submit->fence)) {
                ret = PTR_ERR(submit->fence);
                submit->fence = NULL;
                goto out;
        }

        if (args->flags & MSM_SUBMIT_FENCE_FD_OUT) {
                sync_file = sync_file_create(submit->fence);
                if (!sync_file) {
                        ret = -ENOMEM;
                        goto out;
                }
        }

        msm_gpu_submit(gpu, submit, ctx);

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

        if (args->flags & MSM_SUBMIT_FENCE_FD_OUT) {
                fd_install(out_fence_fd, sync_file->file);
                args->fence_fd = out_fence_fd;
        }

out:
        if (in_fence)
                dma_fence_put(in_fence);
        submit_cleanup(submit);
        if (ret)
                msm_gem_submit_free(submit);
out_unlock:
        if (ret && (out_fence_fd >= 0))
                put_unused_fd(out_fence_fd);
        mutex_unlock(&dev->struct_mutex);
        return ret;
}