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/* drm_lists.h -- Buffer list handling routines -*- linux-c -*-

 * Created: Mon Apr 19 20:54:22 1999 by faith@valinux.com

 *

 * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.

 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.

 * All Rights Reserved.

 *

 * 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 (including the next

 * paragraph) 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

 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS 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:

 *    Rickard E. (Rik) Faith <faith@valinux.com>

 *    Gareth Hughes <gareth@valinux.com>

 */

#include "drmP.h"

#if __HAVE_DMA_WAITLIST

int DRM(waitlist_create)(drm_waitlist_t *bl, int count)

{

        if (bl->count) return -EINVAL;

        bl->bufs       = DRM(alloc)((bl->count + 2) * sizeof(*bl->bufs),

                                    DRM_MEM_BUFLISTS);

        if(!bl->bufs) return -ENOMEM;

        memset(bl->bufs, 0, sizeof(*bl->bufs));

        bl->count      = count;

        bl->rp         = bl->bufs;

        bl->wp         = bl->bufs;

        bl->end        = &bl->bufs[bl->count+1];

        bl->write_lock = SPIN_LOCK_UNLOCKED;

        bl->read_lock  = SPIN_LOCK_UNLOCKED;

        return 0;

}

int DRM(waitlist_destroy)(drm_waitlist_t *bl)

{

        if (bl->rp != bl->wp) return -EINVAL;

        if (bl->bufs) DRM(free)(bl->bufs,

                                (bl->count + 2) * sizeof(*bl->bufs),

                                DRM_MEM_BUFLISTS);

        bl->count = 0;

        bl->bufs  = NULL;

        bl->rp    = NULL;

        bl->wp    = NULL;

        bl->end   = NULL;

        return 0;

}

int DRM(waitlist_put)(drm_waitlist_t *bl, drm_buf_t *buf)

{

        int           left;

        unsigned long flags;

        left = DRM_LEFTCOUNT(bl);

        if (!left) {

                DRM_ERROR("Overflow while adding buffer %d from pid %d\n",

                          buf->idx, buf->pid);

                return -EINVAL;

        }

#if __HAVE_DMA_HISTOGRAM

        buf->time_queued = get_cycles();

#endif

        buf->list        = DRM_LIST_WAIT;

        spin_lock_irqsave(&bl->write_lock, flags);

        *bl->wp = buf;

        if (++bl->wp >= bl->end) bl->wp = bl->bufs;

        spin_unlock_irqrestore(&bl->write_lock, flags);

        return 0;

}

drm_buf_t *DRM(waitlist_get)(drm_waitlist_t *bl)

{

        drm_buf_t     *buf;

        unsigned long flags;

        spin_lock_irqsave(&bl->read_lock, flags);

        buf = *bl->rp;

        if (bl->rp == bl->wp) {

                spin_unlock_irqrestore(&bl->read_lock, flags);

                return NULL;

        }

        if (++bl->rp >= bl->end) bl->rp = bl->bufs;

        spin_unlock_irqrestore(&bl->read_lock, flags);

        return buf;

}

#endif /* __HAVE_DMA_WAITLIST */

#if __HAVE_DMA_FREELIST

int DRM(freelist_create)(drm_freelist_t *bl, int count)

{

        atomic_set(&bl->count, 0);

        bl->next      = NULL;

        init_waitqueue_head(&bl->waiting);

        bl->low_mark  = 0;

        bl->high_mark = 0;

        atomic_set(&bl->wfh,   0);

        bl->lock      = SPIN_LOCK_UNLOCKED;

        ++bl->initialized;

        return 0;

}

int DRM(freelist_destroy)(drm_freelist_t *bl)

{

        atomic_set(&bl->count, 0);

        bl->next = NULL;

        return 0;

}

int DRM(freelist_put)(drm_device_t *dev, drm_freelist_t *bl, drm_buf_t *buf)

{

        drm_device_dma_t *dma  = dev->dma;

        if (!dma) {

                DRM_ERROR("No DMA support\n");

                return 1;

        }

        if (buf->waiting || buf->pending || buf->list == DRM_LIST_FREE) {

                DRM_ERROR("Freed buffer %d: w%d, p%d, l%d\n",

                          buf->idx, buf->waiting, buf->pending, buf->list);

        }

        if (!bl) return 1;

#if __HAVE_DMA_HISTOGRAM

        buf->time_freed = get_cycles();

        DRM(histogram_compute)(dev, buf);

#endif

        buf->list       = DRM_LIST_FREE;

        spin_lock(&bl->lock);

        buf->next       = bl->next;

        bl->next        = buf;

        spin_unlock(&bl->lock);

        atomic_inc(&bl->count);

        if (atomic_read(&bl->count) > dma->buf_count) {

                DRM_ERROR("%d of %d buffers free after addition of %d\n",

                          atomic_read(&bl->count), dma->buf_count, buf->idx);

                return 1;

        }

                                /* Check for high water mark */

        if (atomic_read(&bl->wfh) && atomic_read(&bl->count)>=bl->high_mark) {

                atomic_set(&bl->wfh, 0);

                wake_up_interruptible(&bl->waiting);

        }

        return 0;

}

static drm_buf_t *DRM(freelist_try)(drm_freelist_t *bl)

{

        drm_buf_t         *buf;

        if (!bl) return NULL;

                                /* Get buffer */

        spin_lock(&bl->lock);

        if (!bl->next) {

                spin_unlock(&bl->lock);

                return NULL;

        }

        buf       = bl->next;

        bl->next  = bl->next->next;

        spin_unlock(&bl->lock);

        atomic_dec(&bl->count);

        buf->next = NULL;

        buf->list = DRM_LIST_NONE;

        if (buf->waiting || buf->pending) {

                DRM_ERROR("Free buffer %d: w%d, p%d, l%d\n",

                          buf->idx, buf->waiting, buf->pending, buf->list);

        }

        return buf;

}

drm_buf_t *DRM(freelist_get)(drm_freelist_t *bl, int block)

{

        drm_buf_t         *buf  = NULL;

        DECLARE_WAITQUEUE(entry, current);

        if (!bl || !bl->initialized) return NULL;

                                /* Check for low water mark */

        if (atomic_read(&bl->count) <= bl->low_mark) /* Became low */

                atomic_set(&bl->wfh, 1);

        if (atomic_read(&bl->wfh)) {

                if (block) {

                        add_wait_queue(&bl->waiting, &entry);

                        for (;;) {

                                current->state = TASK_INTERRUPTIBLE;

                                if (!atomic_read(&bl->wfh)

                                    && (buf = DRM(freelist_try)(bl))) break;

                                schedule();

                                if (signal_pending(current)) break;

                        }

                        current->state = TASK_RUNNING;

                        remove_wait_queue(&bl->waiting, &entry);

                }

                return buf;

        }

        return DRM(freelist_try)(bl);

}

#endif /* __HAVE_DMA_FREELIST */