1 files changed, 685 insertions, 0 deletions

diff --git a/drivers/gpu/drm/qxl/qxl_cmd.c b/drivers/gpu/drm/qxl/qxl_cmd.c
new file mode 100644
index 000000000000..08b0823c93d5
--- /dev/null
+++ b/drivers/gpu/drm/qxl/qxl_cmd.c
@@ -0,0 +1,685 @@
+/*
+ * Copyright 2013 Red Hat 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: Dave Airlie
+ *          Alon Levy
+ */
+
+/* QXL cmd/ring handling */
+
+#include "qxl_drv.h"
+#include "qxl_object.h"
+
+static int qxl_reap_surface_id(struct qxl_device *qdev, int max_to_reap);
+
+struct ring {
+        struct qxl_ring_header      header;
+        uint8_t                     elements[0];
+};
+
+struct qxl_ring {
+        struct ring            *ring;
+        int                     element_size;
+        int                     n_elements;
+        int                     prod_notify;
+        wait_queue_head_t      *push_event;
+        spinlock_t             lock;
+};
+
+void qxl_ring_free(struct qxl_ring *ring)
+{
+        kfree(ring);
+}
+
+struct qxl_ring *
+qxl_ring_create(struct qxl_ring_header *header,
+                int element_size,
+                int n_elements,
+                int prod_notify,
+                bool set_prod_notify,
+                wait_queue_head_t *push_event)
+{
+        struct qxl_ring *ring;
+
+        ring = kmalloc(sizeof(*ring), GFP_KERNEL);
+        if (!ring)
+                return NULL;
+
+        ring->ring = (struct ring *)header;
+        ring->element_size = element_size;
+        ring->n_elements = n_elements;
+        ring->prod_notify = prod_notify;
+        ring->push_event = push_event;
+        if (set_prod_notify)
+                header->notify_on_prod = ring->n_elements;
+        spin_lock_init(&ring->lock);
+        return ring;
+}
+
+static int qxl_check_header(struct qxl_ring *ring)
+{
+        int ret;
+        struct qxl_ring_header *header = &(ring->ring->header);
+        unsigned long flags;
+        spin_lock_irqsave(&ring->lock, flags);
+        ret = header->prod - header->cons < header->num_items;
+        if (ret == 0)
+                header->notify_on_cons = header->cons + 1;
+        spin_unlock_irqrestore(&ring->lock, flags);
+        return ret;
+}
+
+static int qxl_check_idle(struct qxl_ring *ring)
+{
+        int ret;
+        struct qxl_ring_header *header = &(ring->ring->header);
+        unsigned long flags;
+        spin_lock_irqsave(&ring->lock, flags);
+        ret = header->prod == header->cons;
+        spin_unlock_irqrestore(&ring->lock, flags);
+        return ret;
+}
+
+int qxl_ring_push(struct qxl_ring *ring,
+                  const void *new_elt, bool interruptible)
+{
+        struct qxl_ring_header *header = &(ring->ring->header);
+        uint8_t *elt;
+        int idx, ret;
+        unsigned long flags;
+        spin_lock_irqsave(&ring->lock, flags);
+        if (header->prod - header->cons == header->num_items) {
+                header->notify_on_cons = header->cons + 1;
+                mb();
+                spin_unlock_irqrestore(&ring->lock, flags);
+                if (!drm_can_sleep()) {
+                        while (!qxl_check_header(ring))
+                                udelay(1);
+                } else {
+                        if (interruptible) {
+                                ret = wait_event_interruptible(*ring->push_event,
+                                                               qxl_check_header(ring));
+                                if (ret)
+                                        return ret;
+                        } else {
+                                wait_event(*ring->push_event,
+                                           qxl_check_header(ring));
+                        }
+
+                }
+                spin_lock_irqsave(&ring->lock, flags);
+        }
+
+        idx = header->prod & (ring->n_elements - 1);
+        elt = ring->ring->elements + idx * ring->element_size;
+
+        memcpy((void *)elt, new_elt, ring->element_size);
+
+        header->prod++;
+
+        mb();
+
+        if (header->prod == header->notify_on_prod)
+                outb(0, ring->prod_notify);
+
+        spin_unlock_irqrestore(&ring->lock, flags);
+        return 0;
+}
+
+static bool qxl_ring_pop(struct qxl_ring *ring,
+                         void *element)
+{
+        volatile struct qxl_ring_header *header = &(ring->ring->header);
+        volatile uint8_t *ring_elt;
+        int idx;
+        unsigned long flags;
+        spin_lock_irqsave(&ring->lock, flags);
+        if (header->cons == header->prod) {
+                header->notify_on_prod = header->cons + 1;
+                spin_unlock_irqrestore(&ring->lock, flags);
+                return false;
+        }
+
+        idx = header->cons & (ring->n_elements - 1);
+        ring_elt = ring->ring->elements + idx * ring->element_size;
+
+        memcpy(element, (void *)ring_elt, ring->element_size);
+
+        header->cons++;
+
+        spin_unlock_irqrestore(&ring->lock, flags);
+        return true;
+}
+
+int
+qxl_push_command_ring_release(struct qxl_device *qdev, struct qxl_release *release,
+                              uint32_t type, bool interruptible)
+{
+        struct qxl_command cmd;
+
+        cmd.type = type;
+        cmd.data = qxl_bo_physical_address(qdev, release->bos[0], release->release_offset);
+
+        return qxl_ring_push(qdev->command_ring, &cmd, interruptible);
+}
+
+int
+qxl_push_cursor_ring_release(struct qxl_device *qdev, struct qxl_release *release,
+                             uint32_t type, bool interruptible)
+{
+        struct qxl_command cmd;
+
+        cmd.type = type;
+        cmd.data = qxl_bo_physical_address(qdev, release->bos[0], release->release_offset);
+
+        return qxl_ring_push(qdev->cursor_ring, &cmd, interruptible);
+}
+
+bool qxl_queue_garbage_collect(struct qxl_device *qdev, bool flush)
+{
+        if (!qxl_check_idle(qdev->release_ring)) {
+                queue_work(qdev->gc_queue, &qdev->gc_work);
+                if (flush)
+                        flush_work(&qdev->gc_work);
+                return true;
+        }
+        return false;
+}
+
+int qxl_garbage_collect(struct qxl_device *qdev)
+{
+        struct qxl_release *release;
+        uint64_t id, next_id;
+        int i = 0;
+        int ret;
+        union qxl_release_info *info;
+
+        while (qxl_ring_pop(qdev->release_ring, &id)) {
+                QXL_INFO(qdev, "popped %lld\n", id);
+                while (id) {
+                        release = qxl_release_from_id_locked(qdev, id);
+                        if (release == NULL)
+                                break;
+
+                        ret = qxl_release_reserve(qdev, release, false);
+                        if (ret) {
+                                qxl_io_log(qdev, "failed to reserve release on garbage collect %lld\n", id);
+                                DRM_ERROR("failed to reserve release %lld\n", id);
+                        }
+
+                        info = qxl_release_map(qdev, release);
+                        next_id = info->next;
+                        qxl_release_unmap(qdev, release, info);
+
+                        qxl_release_unreserve(qdev, release);
+                        QXL_INFO(qdev, "popped %lld, next %lld\n", id,
+                                next_id);
+
+                        switch (release->type) {
+                        case QXL_RELEASE_DRAWABLE:
+                        case QXL_RELEASE_SURFACE_CMD:
+                        case QXL_RELEASE_CURSOR_CMD:
+                                break;
+                        default:
+                                DRM_ERROR("unexpected release type\n");
+                                break;
+                        }
+                        id = next_id;
+
+                        qxl_release_free(qdev, release);
+                        ++i;
+                }
+        }
+
+        QXL_INFO(qdev, "%s: %lld\n", __func__, i);
+
+        return i;
+}
+
+int qxl_alloc_bo_reserved(struct qxl_device *qdev, unsigned long size,
+                          struct qxl_bo **_bo)
+{
+        struct qxl_bo *bo;
+        int ret;
+
+        ret = qxl_bo_create(qdev, size, false /* not kernel - device */,
+                            QXL_GEM_DOMAIN_VRAM, NULL, &bo);
+        if (ret) {
+                DRM_ERROR("failed to allocate VRAM BO\n");
+                return ret;
+        }
+        ret = qxl_bo_reserve(bo, false);
+        if (unlikely(ret != 0))
+                goto out_unref;
+
+        *_bo = bo;
+        return 0;
+out_unref:
+        qxl_bo_unref(&bo);
+        return 0;
+}
+
+static int wait_for_io_cmd_user(struct qxl_device *qdev, uint8_t val, long port)
+{
+        int irq_num;
+        long addr = qdev->io_base + port;
+        int ret;
+
+        mutex_lock(&qdev->async_io_mutex);
+        irq_num = atomic_read(&qdev->irq_received_io_cmd);
+
+
+        if (qdev->last_sent_io_cmd > irq_num) {
+                ret = wait_event_interruptible(qdev->io_cmd_event,
+                                               atomic_read(&qdev->irq_received_io_cmd) > irq_num);
+                if (ret)
+                        goto out;
+                irq_num = atomic_read(&qdev->irq_received_io_cmd);
+        }
+        outb(val, addr);
+        qdev->last_sent_io_cmd = irq_num + 1;
+        ret = wait_event_interruptible(qdev->io_cmd_event,
+                                       atomic_read(&qdev->irq_received_io_cmd) > irq_num);
+out:
+        mutex_unlock(&qdev->async_io_mutex);
+        return ret;
+}
+
+static void wait_for_io_cmd(struct qxl_device *qdev, uint8_t val, long port)
+{
+        int ret;
+
+restart:
+        ret = wait_for_io_cmd_user(qdev, val, port);
+        if (ret == -ERESTARTSYS)
+                goto restart;
+}
+
+int qxl_io_update_area(struct qxl_device *qdev, struct qxl_bo *surf,
+                        const struct qxl_rect *area)
+{
+        int surface_id;
+        uint32_t surface_width, surface_height;
+        int ret;
+
+        if (!surf->hw_surf_alloc)
+                DRM_ERROR("got io update area with no hw surface\n");
+
+        if (surf->is_primary)
+                surface_id = 0;
+        else
+                surface_id = surf->surface_id;
+        surface_width = surf->surf.width;
+        surface_height = surf->surf.height;
+
+        if (area->left < 0 || area->top < 0 ||
+            area->right > surface_width || area->bottom > surface_height) {
+                qxl_io_log(qdev, "%s: not doing area update for "
+                           "%d, (%d,%d,%d,%d) (%d,%d)\n", __func__, surface_id, area->left,
+                           area->top, area->right, area->bottom, surface_width, surface_height);
+                return -EINVAL;
+        }
+        mutex_lock(&qdev->update_area_mutex);
+        qdev->ram_header->update_area = *area;
+        qdev->ram_header->update_surface = surface_id;
+        ret = wait_for_io_cmd_user(qdev, 0, QXL_IO_UPDATE_AREA_ASYNC);
+        mutex_unlock(&qdev->update_area_mutex);
+        return ret;
+}
+
+void qxl_io_notify_oom(struct qxl_device *qdev)
+{
+        outb(0, qdev->io_base + QXL_IO_NOTIFY_OOM);
+}
+
+void qxl_io_flush_release(struct qxl_device *qdev)
+{
+        outb(0, qdev->io_base + QXL_IO_FLUSH_RELEASE);
+}
+
+void qxl_io_flush_surfaces(struct qxl_device *qdev)
+{
+        wait_for_io_cmd(qdev, 0, QXL_IO_FLUSH_SURFACES_ASYNC);
+}
+
+
+void qxl_io_destroy_primary(struct qxl_device *qdev)
+{
+        wait_for_io_cmd(qdev, 0, QXL_IO_DESTROY_PRIMARY_ASYNC);
+}
+
+void qxl_io_create_primary(struct qxl_device *qdev, unsigned width,
+                           unsigned height, unsigned offset, struct qxl_bo *bo)
+{
+        struct qxl_surface_create *create;
+
+        QXL_INFO(qdev, "%s: qdev %p, ram_header %p\n", __func__, qdev,
+                 qdev->ram_header);
+        create = &qdev->ram_header->create_surface;
+        create->format = bo->surf.format;
+        create->width = width;
+        create->height = height;
+        create->stride = bo->surf.stride;
+        create->mem = qxl_bo_physical_address(qdev, bo, offset);
+
+        QXL_INFO(qdev, "%s: mem = %llx, from %p\n", __func__, create->mem,
+                 bo->kptr);
+
+        create->flags = QXL_SURF_FLAG_KEEP_DATA;
+        create->type = QXL_SURF_TYPE_PRIMARY;
+
+        wait_for_io_cmd(qdev, 0, QXL_IO_CREATE_PRIMARY_ASYNC);
+}
+
+void qxl_io_memslot_add(struct qxl_device *qdev, uint8_t id)
+{
+        QXL_INFO(qdev, "qxl_memslot_add %d\n", id);
+        wait_for_io_cmd(qdev, id, QXL_IO_MEMSLOT_ADD_ASYNC);
+}
+
+void qxl_io_log(struct qxl_device *qdev, const char *fmt, ...)
+{
+        va_list args;
+
+        va_start(args, fmt);
+        vsnprintf(qdev->ram_header->log_buf, QXL_LOG_BUF_SIZE, fmt, args);
+        va_end(args);
+        /*
+         * DO not do a DRM output here - this will call printk, which will
+         * call back into qxl for rendering (qxl_fb)
+         */
+        outb(0, qdev->io_base + QXL_IO_LOG);
+}
+
+void qxl_io_reset(struct qxl_device *qdev)
+{
+        outb(0, qdev->io_base + QXL_IO_RESET);
+}
+
+void qxl_io_monitors_config(struct qxl_device *qdev)
+{
+        qxl_io_log(qdev, "%s: %d [%dx%d+%d+%d]\n", __func__,
+                   qdev->monitors_config ?
+                   qdev->monitors_config->count : -1,
+                   qdev->monitors_config && qdev->monitors_config->count ?
+                   qdev->monitors_config->heads[0].width : -1,
+                   qdev->monitors_config && qdev->monitors_config->count ?
+                   qdev->monitors_config->heads[0].height : -1,
+                   qdev->monitors_config && qdev->monitors_config->count ?
+                   qdev->monitors_config->heads[0].x : -1,
+                   qdev->monitors_config && qdev->monitors_config->count ?
+                   qdev->monitors_config->heads[0].y : -1
+                   );
+
+        wait_for_io_cmd(qdev, 0, QXL_IO_MONITORS_CONFIG_ASYNC);
+}
+
+int qxl_surface_id_alloc(struct qxl_device *qdev,
+                      struct qxl_bo *surf)
+{
+        uint32_t handle;
+        int idr_ret;
+        int count = 0;
+again:
+        idr_preload(GFP_ATOMIC);
+        spin_lock(&qdev->surf_id_idr_lock);
+        idr_ret = idr_alloc(&qdev->surf_id_idr, NULL, 1, 0, GFP_NOWAIT);
+        spin_unlock(&qdev->surf_id_idr_lock);
+        idr_preload_end();
+        if (idr_ret < 0)
+                return idr_ret;
+        handle = idr_ret;
+
+        if (handle >= qdev->rom->n_surfaces) {
+                count++;
+                spin_lock(&qdev->surf_id_idr_lock);
+                idr_remove(&qdev->surf_id_idr, handle);
+                spin_unlock(&qdev->surf_id_idr_lock);
+                qxl_reap_surface_id(qdev, 2);
+                goto again;
+        }
+        surf->surface_id = handle;
+
+        spin_lock(&qdev->surf_id_idr_lock);
+        qdev->last_alloced_surf_id = handle;
+        spin_unlock(&qdev->surf_id_idr_lock);
+        return 0;
+}
+
+void qxl_surface_id_dealloc(struct qxl_device *qdev,
+                            uint32_t surface_id)
+{
+        spin_lock(&qdev->surf_id_idr_lock);
+        idr_remove(&qdev->surf_id_idr, surface_id);
+        spin_unlock(&qdev->surf_id_idr_lock);
+}
+
+int qxl_hw_surface_alloc(struct qxl_device *qdev,
+                         struct qxl_bo *surf,
+                         struct ttm_mem_reg *new_mem)
+{
+        struct qxl_surface_cmd *cmd;
+        struct qxl_release *release;
+        int ret;
+
+        if (surf->hw_surf_alloc)
+                return 0;
+
+        ret = qxl_alloc_surface_release_reserved(qdev, QXL_SURFACE_CMD_CREATE,
+                                                 NULL,
+                                                 &release);
+        if (ret)
+                return ret;
+
+        cmd = (struct qxl_surface_cmd *)qxl_release_map(qdev, release);
+        cmd->type = QXL_SURFACE_CMD_CREATE;
+        cmd->u.surface_create.format = surf->surf.format;
+        cmd->u.surface_create.width = surf->surf.width;
+        cmd->u.surface_create.height = surf->surf.height;
+        cmd->u.surface_create.stride = surf->surf.stride;
+        if (new_mem) {
+                int slot_id = surf->type == QXL_GEM_DOMAIN_VRAM ? qdev->main_mem_slot : qdev->surfaces_mem_slot;
+                struct qxl_memslot *slot = &(qdev->mem_slots[slot_id]);
+
+                /* TODO - need to hold one of the locks to read tbo.offset */
+                cmd->u.surface_create.data = slot->high_bits;
+
+                cmd->u.surface_create.data |= (new_mem->start << PAGE_SHIFT) + surf->tbo.bdev->man[new_mem->mem_type].gpu_offset;
+        } else
+                cmd->u.surface_create.data = qxl_bo_physical_address(qdev, surf, 0);
+        cmd->surface_id = surf->surface_id;
+        qxl_release_unmap(qdev, release, &cmd->release_info);
+
+        surf->surf_create = release;
+
+        /* no need to add a release to the fence for this bo,
+           since it is only released when we ask to destroy the surface
+           and it would never signal otherwise */
+        qxl_fence_releaseable(qdev, release);
+
+        qxl_push_command_ring_release(qdev, release, QXL_CMD_SURFACE, false);
+
+        qxl_release_unreserve(qdev, release);
+
+        surf->hw_surf_alloc = true;
+        spin_lock(&qdev->surf_id_idr_lock);
+        idr_replace(&qdev->surf_id_idr, surf, surf->surface_id);
+        spin_unlock(&qdev->surf_id_idr_lock);
+        return 0;
+}
+
+int qxl_hw_surface_dealloc(struct qxl_device *qdev,
+                           struct qxl_bo *surf)
+{
+        struct qxl_surface_cmd *cmd;
+        struct qxl_release *release;
+        int ret;
+        int id;
+
+        if (!surf->hw_surf_alloc)
+                return 0;
+
+        ret = qxl_alloc_surface_release_reserved(qdev, QXL_SURFACE_CMD_DESTROY,
+                                                 surf->surf_create,
+                                                 &release);
+        if (ret)
+                return ret;
+
+        surf->surf_create = NULL;
+        /* remove the surface from the idr, but not the surface id yet */
+        spin_lock(&qdev->surf_id_idr_lock);
+        idr_replace(&qdev->surf_id_idr, NULL, surf->surface_id);
+        spin_unlock(&qdev->surf_id_idr_lock);
+        surf->hw_surf_alloc = false;
+
+        id = surf->surface_id;
+        surf->surface_id = 0;
+
+        release->surface_release_id = id;
+        cmd = (struct qxl_surface_cmd *)qxl_release_map(qdev, release);
+        cmd->type = QXL_SURFACE_CMD_DESTROY;
+        cmd->surface_id = id;
+        qxl_release_unmap(qdev, release, &cmd->release_info);
+
+        qxl_fence_releaseable(qdev, release);
+
+        qxl_push_command_ring_release(qdev, release, QXL_CMD_SURFACE, false);
+
+        qxl_release_unreserve(qdev, release);
+
+
+        return 0;
+}
+
+int qxl_update_surface(struct qxl_device *qdev, struct qxl_bo *surf)
+{
+        struct qxl_rect rect;
+        int ret;
+
+        /* if we are evicting, we need to make sure the surface is up
+           to date */
+        rect.left = 0;
+        rect.right = surf->surf.width;
+        rect.top = 0;
+        rect.bottom = surf->surf.height;
+retry:
+        ret = qxl_io_update_area(qdev, surf, &rect);
+        if (ret == -ERESTARTSYS)
+                goto retry;
+        return ret;
+}
+
+static void qxl_surface_evict_locked(struct qxl_device *qdev, struct qxl_bo *surf, bool do_update_area)
+{
+        /* no need to update area if we are just freeing the surface normally */
+        if (do_update_area)
+                qxl_update_surface(qdev, surf);
+
+        /* nuke the surface id at the hw */
+        qxl_hw_surface_dealloc(qdev, surf);
+}
+
+void qxl_surface_evict(struct qxl_device *qdev, struct qxl_bo *surf, bool do_update_area)
+{
+        mutex_lock(&qdev->surf_evict_mutex);
+        qxl_surface_evict_locked(qdev, surf, do_update_area);
+        mutex_unlock(&qdev->surf_evict_mutex);
+}
+
+static int qxl_reap_surf(struct qxl_device *qdev, struct qxl_bo *surf, bool stall)
+{
+        int ret;
+
+        ret = qxl_bo_reserve(surf, false);
+        if (ret == -EBUSY)
+                return -EBUSY;
+
+        if (surf->fence.num_active_releases > 0 && stall == false) {
+                qxl_bo_unreserve(surf);
+                return -EBUSY;
+        }
+
+        if (stall)
+                mutex_unlock(&qdev->surf_evict_mutex);
+
+        spin_lock(&surf->tbo.bdev->fence_lock);
+        ret = ttm_bo_wait(&surf->tbo, true, true, !stall);
+        spin_unlock(&surf->tbo.bdev->fence_lock);
+
+        if (stall)
+                mutex_lock(&qdev->surf_evict_mutex);
+        if (ret == -EBUSY) {
+                qxl_bo_unreserve(surf);
+                return -EBUSY;
+        }
+
+        qxl_surface_evict_locked(qdev, surf, true);
+        qxl_bo_unreserve(surf);
+        return 0;
+}
+
+static int qxl_reap_surface_id(struct qxl_device *qdev, int max_to_reap)
+{
+        int num_reaped = 0;
+        int i, ret;
+        bool stall = false;
+        int start = 0;
+
+        mutex_lock(&qdev->surf_evict_mutex);
+again:
+
+        spin_lock(&qdev->surf_id_idr_lock);
+        start = qdev->last_alloced_surf_id + 1;
+        spin_unlock(&qdev->surf_id_idr_lock);
+
+        for (i = start; i < start + qdev->rom->n_surfaces; i++) {
+                void *objptr;
+                int surfid = i % qdev->rom->n_surfaces;
+
+                /* this avoids the case where the objects is in the
+                   idr but has been evicted half way - its makes
+                   the idr lookup atomic with the eviction */
+                spin_lock(&qdev->surf_id_idr_lock);
+                objptr = idr_find(&qdev->surf_id_idr, surfid);
+                spin_unlock(&qdev->surf_id_idr_lock);
+
+                if (!objptr)
+                        continue;
+
+                ret = qxl_reap_surf(qdev, objptr, stall);
+                if (ret == 0)
+                        num_reaped++;
+                if (num_reaped >= max_to_reap)
+                        break;
+        }
+        if (num_reaped == 0 && stall == false) {
+                stall = true;
+                goto again;
+        }
+
+        mutex_unlock(&qdev->surf_evict_mutex);
+        if (num_reaped) {
+                usleep_range(500, 1000);
+                qxl_queue_garbage_collect(qdev, true);
+        }
+
+        return 0;
+}