v4l2-mem2mem.c

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/*
 * Memory-to-memory device framework for Video for Linux 2 and videobuf.
 *
 * Helper functions for devices that use videobuf buffers for both their
 * source and destination.
 *
 * Copyright (c) 2009-2010 Samsung Electronics Co., Ltd.
 * Pawel Osciak, <[email protected]>
 * Marek Szyprowski, <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 */
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/slab.h>

#include <media/videobuf2-core.h>
#include <media/v4l2-mem2mem.h>
#include <media/v4l2-dev.h>
#include <media/v4l2-fh.h>
#include <media/v4l2-event.h>

MODULE_DESCRIPTION("Mem to mem device framework for videobuf");
MODULE_AUTHOR("Pawel Osciak, <[email protected]>");
MODULE_LICENSE("GPL");

static bool debug;
module_param(debug, bool, 0644);

#define dprintk(fmt, arg...)                        \
    do {                                \
        if (debug)                      \
            printk(KERN_DEBUG "%s: " fmt, __func__, ## arg);\
    } while (0)


/* Instance is already queued on the job_queue */
#define TRANS_QUEUED        (1 << 0)
/* Instance is currently running in hardware */
#define TRANS_RUNNING       (1 << 1)


/* Offset base for buffers on the destination queue - used to distinguish
 * between source and destination buffers when mmapping - they receive the same
 * offsets but for different queues */
#define DST_QUEUE_OFF_BASE  (1 << 30)


struct v4l2_m2m_dev {
    struct v4l2_m2m_ctx *curr_ctx;

    struct list_head    job_queue;
    spinlock_t      job_spinlock;

    struct v4l2_m2m_ops *m2m_ops;
};

static struct v4l2_m2m_queue_ctx *get_queue_ctx(struct v4l2_m2m_ctx *m2m_ctx,
                        enum v4l2_buf_type type)
{
    if (V4L2_TYPE_IS_OUTPUT(type))
        return &m2m_ctx->out_q_ctx;
    else
        return &m2m_ctx->cap_q_ctx;
}

struct vb2_queue *v4l2_m2m_get_vq(struct v4l2_m2m_ctx *m2m_ctx,
                       enum v4l2_buf_type type)
{
    struct v4l2_m2m_queue_ctx *q_ctx;

    q_ctx = get_queue_ctx(m2m_ctx, type);
    if (!q_ctx)
        return NULL;

    return &q_ctx->q;
}
EXPORT_SYMBOL(v4l2_m2m_get_vq);

void *v4l2_m2m_next_buf(struct v4l2_m2m_queue_ctx *q_ctx)
{
    struct v4l2_m2m_buffer *b = NULL;
    unsigned long flags;

    spin_lock_irqsave(&q_ctx->rdy_spinlock, flags);

    if (list_empty(&q_ctx->rdy_queue)) {
        spin_unlock_irqrestore(&q_ctx->rdy_spinlock, flags);
        return NULL;
    }

    b = list_first_entry(&q_ctx->rdy_queue, struct v4l2_m2m_buffer, list);
    spin_unlock_irqrestore(&q_ctx->rdy_spinlock, flags);
    return &b->vb;
}
EXPORT_SYMBOL_GPL(v4l2_m2m_next_buf);

void *v4l2_m2m_buf_remove(struct v4l2_m2m_queue_ctx *q_ctx)
{
    struct v4l2_m2m_buffer *b = NULL;
    unsigned long flags;

    spin_lock_irqsave(&q_ctx->rdy_spinlock, flags);
    if (list_empty(&q_ctx->rdy_queue)) {
        spin_unlock_irqrestore(&q_ctx->rdy_spinlock, flags);
        return NULL;
    }
    b = list_first_entry(&q_ctx->rdy_queue, struct v4l2_m2m_buffer, list);
    list_del(&b->list);
    q_ctx->num_rdy--;
    spin_unlock_irqrestore(&q_ctx->rdy_spinlock, flags);

    return &b->vb;
}
EXPORT_SYMBOL_GPL(v4l2_m2m_buf_remove);

/*
 * Scheduling handlers
 */

void *v4l2_m2m_get_curr_priv(struct v4l2_m2m_dev *m2m_dev)
{
    unsigned long flags;
    void *ret = NULL;

    spin_lock_irqsave(&m2m_dev->job_spinlock, flags);
    if (m2m_dev->curr_ctx)
        ret = m2m_dev->curr_ctx->priv;
    spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);

    return ret;
}
EXPORT_SYMBOL(v4l2_m2m_get_curr_priv);

static void v4l2_m2m_try_run(struct v4l2_m2m_dev *m2m_dev)
{
    unsigned long flags;

    spin_lock_irqsave(&m2m_dev->job_spinlock, flags);
    if (NULL != m2m_dev->curr_ctx) {
        spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
        dprintk("Another instance is running, won't run now\n");
        return;
    }

    if (list_empty(&m2m_dev->job_queue)) {
        spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
        dprintk("No job pending\n");
        return;
    }

    m2m_dev->curr_ctx = list_first_entry(&m2m_dev->job_queue,
                   struct v4l2_m2m_ctx, queue);
    m2m_dev->curr_ctx->job_flags |= TRANS_RUNNING;
    spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);

    m2m_dev->m2m_ops->device_run(m2m_dev->curr_ctx->priv);
}

static void v4l2_m2m_try_schedule(struct v4l2_m2m_ctx *m2m_ctx)
{
    struct v4l2_m2m_dev *m2m_dev;
    unsigned long flags_job, flags;

    m2m_dev = m2m_ctx->m2m_dev;
    dprintk("Trying to schedule a job for m2m_ctx: %p\n", m2m_ctx);

    if (!m2m_ctx->out_q_ctx.q.streaming
        || !m2m_ctx->cap_q_ctx.q.streaming) {
        dprintk("Streaming needs to be on for both queues\n");
        return;
    }

    spin_lock_irqsave(&m2m_dev->job_spinlock, flags_job);
    if (m2m_ctx->job_flags & TRANS_QUEUED) {
        spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags_job);
        dprintk("On job queue already\n");
        return;
    }

    spin_lock_irqsave(&m2m_ctx->out_q_ctx.rdy_spinlock, flags);
    if (list_empty(&m2m_ctx->out_q_ctx.rdy_queue)) {
        spin_unlock_irqrestore(&m2m_ctx->out_q_ctx.rdy_spinlock, flags);
        spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags_job);
        dprintk("No input buffers available\n");
        return;
    }
    if (list_empty(&m2m_ctx->cap_q_ctx.rdy_queue)) {
        spin_unlock_irqrestore(&m2m_ctx->out_q_ctx.rdy_spinlock, flags);
        spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags_job);
        dprintk("No output buffers available\n");
        return;
    }
    spin_unlock_irqrestore(&m2m_ctx->out_q_ctx.rdy_spinlock, flags);

    if (m2m_dev->m2m_ops->job_ready
        && (!m2m_dev->m2m_ops->job_ready(m2m_ctx->priv))) {
        spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags_job);
        dprintk("Driver not ready\n");
        return;
    }

    list_add_tail(&m2m_ctx->queue, &m2m_dev->job_queue);
    m2m_ctx->job_flags |= TRANS_QUEUED;

    spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags_job);

    v4l2_m2m_try_run(m2m_dev);
}

void v4l2_m2m_job_finish(struct v4l2_m2m_dev *m2m_dev,
             struct v4l2_m2m_ctx *m2m_ctx)
{
    unsigned long flags;

    spin_lock_irqsave(&m2m_dev->job_spinlock, flags);
    if (!m2m_dev->curr_ctx || m2m_dev->curr_ctx != m2m_ctx) {
        spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
        dprintk("Called by an instance not currently running\n");
        return;
    }

    list_del(&m2m_dev->curr_ctx->queue);
    m2m_dev->curr_ctx->job_flags &= ~(TRANS_QUEUED | TRANS_RUNNING);
    wake_up(&m2m_dev->curr_ctx->finished);
    m2m_dev->curr_ctx = NULL;

    spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);

    /* This instance might have more buffers ready, but since we do not
     * allow more than one job on the job_queue per instance, each has
     * to be scheduled separately after the previous one finishes. */
    v4l2_m2m_try_schedule(m2m_ctx);
    v4l2_m2m_try_run(m2m_dev);
}
EXPORT_SYMBOL(v4l2_m2m_job_finish);

int v4l2_m2m_reqbufs(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
             struct v4l2_requestbuffers *reqbufs)
{
    struct vb2_queue *vq;

    vq = v4l2_m2m_get_vq(m2m_ctx, reqbufs->type);
    return vb2_reqbufs(vq, reqbufs);
}
EXPORT_SYMBOL_GPL(v4l2_m2m_reqbufs);

int v4l2_m2m_querybuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
              struct v4l2_buffer *buf)
{
    struct vb2_queue *vq;
    int ret = 0;
    unsigned int i;

    vq = v4l2_m2m_get_vq(m2m_ctx, buf->type);
    ret = vb2_querybuf(vq, buf);

    /* Adjust MMAP memory offsets for the CAPTURE queue */
    if (buf->memory == V4L2_MEMORY_MMAP && !V4L2_TYPE_IS_OUTPUT(vq->type)) {
        if (V4L2_TYPE_IS_MULTIPLANAR(vq->type)) {
            for (i = 0; i < buf->length; ++i)
                buf->m.planes[i].m.mem_offset
                    += DST_QUEUE_OFF_BASE;
        } else {
            buf->m.offset += DST_QUEUE_OFF_BASE;
        }
    }

    return ret;
}
EXPORT_SYMBOL_GPL(v4l2_m2m_querybuf);

int v4l2_m2m_qbuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
          struct v4l2_buffer *buf)
{
    struct vb2_queue *vq;
    int ret;

    vq = v4l2_m2m_get_vq(m2m_ctx, buf->type);
    ret = vb2_qbuf(vq, buf);
    if (!ret)
        v4l2_m2m_try_schedule(m2m_ctx);

    return ret;
}
EXPORT_SYMBOL_GPL(v4l2_m2m_qbuf);

int v4l2_m2m_dqbuf(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
           struct v4l2_buffer *buf)
{
    struct vb2_queue *vq;

    vq = v4l2_m2m_get_vq(m2m_ctx, buf->type);
    return vb2_dqbuf(vq, buf, file->f_flags & O_NONBLOCK);
}
EXPORT_SYMBOL_GPL(v4l2_m2m_dqbuf);

int v4l2_m2m_streamon(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
              enum v4l2_buf_type type)
{
    struct vb2_queue *vq;
    int ret;

    vq = v4l2_m2m_get_vq(m2m_ctx, type);
    ret = vb2_streamon(vq, type);
    if (!ret)
        v4l2_m2m_try_schedule(m2m_ctx);

    return ret;
}
EXPORT_SYMBOL_GPL(v4l2_m2m_streamon);

int v4l2_m2m_streamoff(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
               enum v4l2_buf_type type)
{
    struct vb2_queue *vq;

    vq = v4l2_m2m_get_vq(m2m_ctx, type);
    return vb2_streamoff(vq, type);
}
EXPORT_SYMBOL_GPL(v4l2_m2m_streamoff);

unsigned int v4l2_m2m_poll(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
               struct poll_table_struct *wait)
{
    struct video_device *vfd = video_devdata(file);
    unsigned long req_events = poll_requested_events(wait);
    struct vb2_queue *src_q, *dst_q;
    struct vb2_buffer *src_vb = NULL, *dst_vb = NULL;
    unsigned int rc = 0;
    unsigned long flags;

    if (test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags)) {
        struct v4l2_fh *fh = file->private_data;

        if (v4l2_event_pending(fh))
            rc = POLLPRI;
        else if (req_events & POLLPRI)
            poll_wait(file, &fh->wait, wait);
        if (!(req_events & (POLLOUT | POLLWRNORM | POLLIN | POLLRDNORM)))
            return rc;
    }

    src_q = v4l2_m2m_get_src_vq(m2m_ctx);
    dst_q = v4l2_m2m_get_dst_vq(m2m_ctx);

    /*
     * There has to be at least one buffer queued on each queued_list, which
     * means either in driver already or waiting for driver to claim it
     * and start processing.
     */
    if ((!src_q->streaming || list_empty(&src_q->queued_list))
        && (!dst_q->streaming || list_empty(&dst_q->queued_list))) {
        rc |= POLLERR;
        goto end;
    }

    if (m2m_ctx->m2m_dev->m2m_ops->unlock)
        m2m_ctx->m2m_dev->m2m_ops->unlock(m2m_ctx->priv);

    poll_wait(file, &src_q->done_wq, wait);
    poll_wait(file, &dst_q->done_wq, wait);

    if (m2m_ctx->m2m_dev->m2m_ops->lock)
        m2m_ctx->m2m_dev->m2m_ops->lock(m2m_ctx->priv);

    spin_lock_irqsave(&src_q->done_lock, flags);
    if (!list_empty(&src_q->done_list))
        src_vb = list_first_entry(&src_q->done_list, struct vb2_buffer,
                        done_entry);
    if (src_vb && (src_vb->state == VB2_BUF_STATE_DONE
            || src_vb->state == VB2_BUF_STATE_ERROR))
        rc |= POLLOUT | POLLWRNORM;
    spin_unlock_irqrestore(&src_q->done_lock, flags);

    spin_lock_irqsave(&dst_q->done_lock, flags);
    if (!list_empty(&dst_q->done_list))
        dst_vb = list_first_entry(&dst_q->done_list, struct vb2_buffer,
                        done_entry);
    if (dst_vb && (dst_vb->state == VB2_BUF_STATE_DONE
            || dst_vb->state == VB2_BUF_STATE_ERROR))
        rc |= POLLIN | POLLRDNORM;
    spin_unlock_irqrestore(&dst_q->done_lock, flags);

end:
    return rc;
}
EXPORT_SYMBOL_GPL(v4l2_m2m_poll);

int v4l2_m2m_mmap(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
             struct vm_area_struct *vma)
{
    unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
    struct vb2_queue *vq;

    if (offset < DST_QUEUE_OFF_BASE) {
        vq = v4l2_m2m_get_src_vq(m2m_ctx);
    } else {
        vq = v4l2_m2m_get_dst_vq(m2m_ctx);
        vma->vm_pgoff -= (DST_QUEUE_OFF_BASE >> PAGE_SHIFT);
    }

    return vb2_mmap(vq, vma);
}
EXPORT_SYMBOL(v4l2_m2m_mmap);

struct v4l2_m2m_dev *v4l2_m2m_init(struct v4l2_m2m_ops *m2m_ops)
{
    struct v4l2_m2m_dev *m2m_dev;

    if (!m2m_ops)
        return ERR_PTR(-EINVAL);

    BUG_ON(!m2m_ops->device_run);
    BUG_ON(!m2m_ops->job_abort);

    m2m_dev = kzalloc(sizeof *m2m_dev, GFP_KERNEL);
    if (!m2m_dev)
        return ERR_PTR(-ENOMEM);

    m2m_dev->curr_ctx = NULL;
    m2m_dev->m2m_ops = m2m_ops;
    INIT_LIST_HEAD(&m2m_dev->job_queue);
    spin_lock_init(&m2m_dev->job_spinlock);

    return m2m_dev;
}
EXPORT_SYMBOL_GPL(v4l2_m2m_init);

void v4l2_m2m_release(struct v4l2_m2m_dev *m2m_dev)
{
    kfree(m2m_dev);
}
EXPORT_SYMBOL_GPL(v4l2_m2m_release);

struct v4l2_m2m_ctx *v4l2_m2m_ctx_init(struct v4l2_m2m_dev *m2m_dev,
        void *drv_priv,
        int (*queue_init)(void *priv, struct vb2_queue *src_vq, struct vb2_queue *dst_vq))
{
    struct v4l2_m2m_ctx *m2m_ctx;
    struct v4l2_m2m_queue_ctx *out_q_ctx, *cap_q_ctx;
    int ret;

    m2m_ctx = kzalloc(sizeof *m2m_ctx, GFP_KERNEL);
    if (!m2m_ctx)
        return ERR_PTR(-ENOMEM);

    m2m_ctx->priv = drv_priv;
    m2m_ctx->m2m_dev = m2m_dev;
    init_waitqueue_head(&m2m_ctx->finished);

    out_q_ctx = &m2m_ctx->out_q_ctx;
    cap_q_ctx = &m2m_ctx->cap_q_ctx;

    INIT_LIST_HEAD(&out_q_ctx->rdy_queue);
    INIT_LIST_HEAD(&cap_q_ctx->rdy_queue);
    spin_lock_init(&out_q_ctx->rdy_spinlock);
    spin_lock_init(&cap_q_ctx->rdy_spinlock);

    INIT_LIST_HEAD(&m2m_ctx->queue);

    ret = queue_init(drv_priv, &out_q_ctx->q, &cap_q_ctx->q);

    if (ret)
        goto err;

    return m2m_ctx;
err:
    kfree(m2m_ctx);
    return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(v4l2_m2m_ctx_init);

void v4l2_m2m_ctx_release(struct v4l2_m2m_ctx *m2m_ctx)
{
    struct v4l2_m2m_dev *m2m_dev;
    unsigned long flags;

    m2m_dev = m2m_ctx->m2m_dev;

    spin_lock_irqsave(&m2m_dev->job_spinlock, flags);
    if (m2m_ctx->job_flags & TRANS_RUNNING) {
        spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
        m2m_dev->m2m_ops->job_abort(m2m_ctx->priv);
        dprintk("m2m_ctx %p running, will wait to complete", m2m_ctx);
        wait_event(m2m_ctx->finished, !(m2m_ctx->job_flags & TRANS_RUNNING));
    } else if (m2m_ctx->job_flags & TRANS_QUEUED) {
        list_del(&m2m_ctx->queue);
        m2m_ctx->job_flags &= ~(TRANS_QUEUED | TRANS_RUNNING);
        spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
        dprintk("m2m_ctx: %p had been on queue and was removed\n",
            m2m_ctx);
    } else {
        /* Do nothing, was not on queue/running */
        spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);
    }

    vb2_queue_release(&m2m_ctx->cap_q_ctx.q);
    vb2_queue_release(&m2m_ctx->out_q_ctx.q);

    kfree(m2m_ctx);
}
EXPORT_SYMBOL_GPL(v4l2_m2m_ctx_release);

void v4l2_m2m_buf_queue(struct v4l2_m2m_ctx *m2m_ctx, struct vb2_buffer *vb)
{
    struct v4l2_m2m_buffer *b = container_of(vb, struct v4l2_m2m_buffer, vb);
    struct v4l2_m2m_queue_ctx *q_ctx;
    unsigned long flags;

    q_ctx = get_queue_ctx(m2m_ctx, vb->vb2_queue->type);
    if (!q_ctx)
        return;

    spin_lock_irqsave(&q_ctx->rdy_spinlock, flags);
    list_add_tail(&b->list, &q_ctx->rdy_queue);
    q_ctx->num_rdy++;
    spin_unlock_irqrestore(&q_ctx->rdy_spinlock, flags);
}
EXPORT_SYMBOL_GPL(v4l2_m2m_buf_queue);