/*
 * 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 <linux/delay.h>

#include <drm/drm_util.h>

#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[];
};

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);
}

void qxl_ring_init_hdr(struct qxl_ring *ring)
{
        ring->ring->header.notify_on_prod = ring->n_elements;
}

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)
                qxl_ring_init_hdr(ring);
        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;
}

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->release_bo, 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->release_bo, 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)) {
                schedule_work(&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;
        union qxl_release_info *info;

        while (qxl_ring_pop(qdev->release_ring, &id)) {
                DRM_DEBUG_DRIVER("popped %lld\n", id);
                while (id) {
                        release = qxl_release_from_id_locked(qdev, id);
                        if (release == NULL)
                                break;

                        info = qxl_release_map(qdev, release);
                        next_id = info->next;
                        qxl_release_unmap(qdev, release, info);

                        DRM_DEBUG_DRIVER("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;
                }
        }

        DRM_DEBUG_DRIVER("%d\n", i);

        return i;
}

int qxl_alloc_bo_reserved(struct qxl_device *qdev,
                          struct qxl_release *release,
                          unsigned long size,
                          struct qxl_bo **_bo)
{
        struct qxl_bo *bo;
        int ret;

        ret = qxl_bo_create(qdev, size, false /* not kernel - device */,
                            false, QXL_GEM_DOMAIN_VRAM, NULL, &bo);
        if (ret) {
                DRM_ERROR("failed to allocate VRAM BO\n");
                return ret;
        }
        ret = qxl_release_list_add(release, bo);
        if (ret)
                goto out_unref;

        *_bo = bo;
        return 0;
out_unref:
        qxl_bo_unref(&bo);
        return ret;
}

static int wait_for_io_cmd_user(struct qxl_device *qdev, uint8_t val, long port, bool intr)
{
        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) {
                if (intr)
                        ret = wait_event_interruptible_timeout(qdev->io_cmd_event,
                                                               atomic_read(&qdev->irq_received_io_cmd) > irq_num, 5*HZ);
                else
                        ret = wait_event_timeout(qdev->io_cmd_event,
                                                 atomic_read(&qdev->irq_received_io_cmd) > irq_num, 5*HZ);
                /* 0 is timeout, just bail the "hw" has gone away */
                if (ret <= 0)
                        goto out;
                irq_num = atomic_read(&qdev->irq_received_io_cmd);
        }
        outb(val, addr);
        qdev->last_sent_io_cmd = irq_num + 1;
        if (intr)
                ret = wait_event_interruptible_timeout(qdev->io_cmd_event,
                                                       atomic_read(&qdev->irq_received_io_cmd) > irq_num, 5*HZ);
        else
                ret = wait_event_timeout(qdev->io_cmd_event,
                                         atomic_read(&qdev->irq_received_io_cmd) > irq_num, 5*HZ);
out:
        if (ret > 0)
                ret = 0;
        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, false);
        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)
                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, true);
        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);
        qdev->primary_bo->is_primary = false;
        drm_gem_object_put(&qdev->primary_bo->tbo.base);
        qdev->primary_bo = NULL;
}

void qxl_io_create_primary(struct qxl_device *qdev, struct qxl_bo *bo)
{
        struct qxl_surface_create *create;

        if (WARN_ON(qdev->primary_bo))
                return;

        DRM_DEBUG_DRIVER("qdev %p, ram_header %p\n", qdev, qdev->ram_header);
        create = &qdev->ram_header->create_surface;
        create->format = bo->surf.format;
        create->width = bo->surf.width;
        create->height = bo->surf.height;
        create->stride = bo->surf.stride;
        create->mem = qxl_bo_physical_address(qdev, bo, 0);

        DRM_DEBUG_DRIVER("mem = %llx, from %p\n", 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);
        qdev->primary_bo = bo;
        qdev->primary_bo->is_primary = true;
        drm_gem_object_get(&qdev->primary_bo->tbo.base);
}

void qxl_io_memslot_add(struct qxl_device *qdev, uint8_t id)
{
        DRM_DEBUG_DRIVER("qxl_memslot_add %d\n", id);
        wait_for_io_cmd(qdev, id, QXL_IO_MEMSLOT_ADD_ASYNC);
}

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)
{
        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 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;

        ret = qxl_release_reserve_list(release, true);
        if (ret) {
                qxl_release_free(qdev, release);
                return ret;
        }
        cmd = (struct qxl_surface_cmd *)qxl_release_map(qdev, release);
        cmd->type = QXL_SURFACE_CMD_CREATE;
        cmd->flags = QXL_SURF_FLAG_KEEP_DATA;
        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;
        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 surface bo,
           since it is only released when we ask to destroy the surface
           and it would never signal otherwise */
        qxl_release_fence_buffer_objects(release);
        qxl_push_command_ring_release(qdev, release, QXL_CMD_SURFACE, false);

        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_release_fence_buffer_objects(release);
        qxl_push_command_ring_release(qdev, release, QXL_CMD_SURFACE, false);

        return 0;
}

static 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)
                return ret;

        if (stall)
                mutex_unlock(&qdev->surf_evict_mutex);

        ret = ttm_bo_wait(&surf->tbo, true, !stall);

        if (stall)
                mutex_lock(&qdev->surf_evict_mutex);
        if (ret) {
                qxl_bo_unreserve(surf);
                return ret;
        }

        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;
}