drm_dma.h

这个linux源代码是很全面的~基本完整了~使用c编译的~由于时间问题我没有亲自测试~但就算用来做参考资料也是非常好的

		idx = d->send_indices[i];
		if (idx < 0 || idx >= dma->buf_count) {
			atomic_dec(&q->use_count);
			DRM_ERROR("Index %d (of %d max)\n",
				  d->send_indices[i], dma->buf_count - 1);
			return -EINVAL;
		}
		buf = dma->buflist[ idx ];
		if (buf->pid != current->pid) {
			atomic_dec(&q->use_count);
			DRM_ERROR("Process %d using buffer owned by %d\n",
				  current->pid, buf->pid);
			return -EINVAL;
		}
		if (buf->list != DRM_LIST_NONE) {
			atomic_dec(&q->use_count);
			DRM_ERROR("Process %d using buffer %d on list %d\n",
				  current->pid, buf->idx, buf->list);
		}
		buf->used	  = d->send_sizes[i];
		buf->while_locked = while_locked;
		buf->context	  = d->context;
		if (!buf->used) {
			DRM_ERROR("Queueing 0 length buffer\n");
		}
		if (buf->pending) {
			atomic_dec(&q->use_count);
			DRM_ERROR("Queueing pending buffer:"
				  " buffer %d, offset %d\n",
				  d->send_indices[i], i);
			return -EINVAL;
		}
		if (buf->waiting) {
			atomic_dec(&q->use_count);
			DRM_ERROR("Queueing waiting buffer:"
				  " buffer %d, offset %d\n",
				  d->send_indices[i], i);
			return -EINVAL;
		}
		buf->waiting = 1;
		if (atomic_read(&q->use_count) == 1
		    || atomic_read(&q->finalization)) {
			DRM(free_buffer)(dev, buf);
		} else {
			DRM(waitlist_put)(&q->waitlist, buf);
			atomic_inc(&q->total_queued);
		}
	}
	atomic_dec(&q->use_count);

	return 0;
}

static int DRM(dma_get_buffers_of_order)(drm_device_t *dev, drm_dma_t *d,
					 int order)
{
	int		  i;
	drm_buf_t	  *buf;
	drm_device_dma_t  *dma = dev->dma;

	for (i = d->granted_count; i < d->request_count; i++) {
		buf = DRM(freelist_get)(&dma->bufs[order].freelist,
					d->flags & _DRM_DMA_WAIT);
		if (!buf) break;
		if (buf->pending || buf->waiting) {
			DRM_ERROR("Free buffer %d in use by %d (w%d, p%d)\n",
				  buf->idx,
				  buf->pid,
				  buf->waiting,
				  buf->pending);
		}
		buf->pid     = current->pid;
		if (copy_to_user(&d->request_indices[i],
				 &buf->idx,
				 sizeof(buf->idx)))
			return -EFAULT;

		if (copy_to_user(&d->request_sizes[i],
				 &buf->total,
				 sizeof(buf->total)))
			return -EFAULT;

		++d->granted_count;
	}
	return 0;
}


int DRM(dma_get_buffers)(drm_device_t *dev, drm_dma_t *dma)
{
	int		  order;
	int		  retcode = 0;
	int		  tmp_order;

	order = DRM(order)(dma->request_size);

	dma->granted_count = 0;
	retcode		   = DRM(dma_get_buffers_of_order)(dev, dma, order);

	if (dma->granted_count < dma->request_count
	    && (dma->flags & _DRM_DMA_SMALLER_OK)) {
		for (tmp_order = order - 1;
		     !retcode
			     && dma->granted_count < dma->request_count
			     && tmp_order >= DRM_MIN_ORDER;
		     --tmp_order) {

			retcode = DRM(dma_get_buffers_of_order)(dev, dma,
								tmp_order);
		}
	}

	if (dma->granted_count < dma->request_count
	    && (dma->flags & _DRM_DMA_LARGER_OK)) {
		for (tmp_order = order + 1;
		     !retcode
			     && dma->granted_count < dma->request_count
			     && tmp_order <= DRM_MAX_ORDER;
		     ++tmp_order) {

			retcode = DRM(dma_get_buffers_of_order)(dev, dma,
								tmp_order);
		}
	}
	return 0;
}

#endif /* __HAVE_OLD_DMA */


#if __HAVE_DMA_IRQ

int DRM(irq_install)( drm_device_t *dev, int irq )
{
	int ret;

	if ( !irq )
		return -EINVAL;

	down( &dev->struct_sem );
	if ( dev->irq ) {
		up( &dev->struct_sem );
		return -EBUSY;
	}
	dev->irq = irq;
	up( &dev->struct_sem );

	DRM_DEBUG( "%s: irq=%d\n", __FUNCTION__, irq );

	dev->context_flag = 0;
	dev->interrupt_flag = 0;
	dev->dma_flag = 0;

	dev->dma->next_buffer = NULL;
	dev->dma->next_queue = NULL;
	dev->dma->this_buffer = NULL;

#if __HAVE_DMA_IRQ_BH
	INIT_LIST_HEAD( &dev->tq.list );
	dev->tq.sync = 0;
	dev->tq.routine = DRM(dma_immediate_bh);
	dev->tq.data = dev;
#endif

#if __HAVE_VBL_IRQ
	init_waitqueue_head(&dev->vbl_queue);

	spin_lock_init( &dev->vbl_lock );

	INIT_LIST_HEAD( &dev->vbl_sigs.head );

	dev->vbl_pending = 0;
#endif

				/* Before installing handler */
	DRM(driver_irq_preinstall)(dev);

				/* Install handler */
	ret = request_irq( dev->irq, DRM(dma_service),
			   DRM_IRQ_TYPE, dev->devname, dev );
	if ( ret < 0 ) {
		down( &dev->struct_sem );
		dev->irq = 0;
		up( &dev->struct_sem );
		return ret;
	}

				/* After installing handler */
	DRM(driver_irq_postinstall)(dev);

	return 0;
}

int DRM(irq_uninstall)( drm_device_t *dev )
{
	int irq;

	down( &dev->struct_sem );
	irq = dev->irq;
	dev->irq = 0;
	up( &dev->struct_sem );

	if ( !irq )
		return -EINVAL;

	DRM_DEBUG( "%s: irq=%d\n", __FUNCTION__, irq );

	DRM(driver_irq_uninstall)( dev );

	free_irq( irq, dev );

	return 0;
}

int DRM(control)( struct inode *inode, struct file *filp,
		  unsigned int cmd, unsigned long arg )
{
	drm_file_t *priv = filp->private_data;
	drm_device_t *dev = priv->dev;
	drm_control_t ctl;

	if ( copy_from_user( &ctl, (drm_control_t *)arg, sizeof(ctl) ) )
		return -EFAULT;

	switch ( ctl.func ) {
	case DRM_INST_HANDLER:
		return DRM(irq_install)( dev, ctl.irq );
	case DRM_UNINST_HANDLER:
		return DRM(irq_uninstall)( dev );
	default:
		return -EINVAL;
	}
}

#if __HAVE_VBL_IRQ

int DRM(wait_vblank)(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long data )
{
	drm_file_t *priv = filp->private_data;
	drm_device_t *dev = priv->dev;
	drm_wait_vblank_t vblwait;
	struct timeval now;
	int ret = 0;
	unsigned int flags;

	if (!dev->irq)
		return -EINVAL;

	DRM_COPY_FROM_USER_IOCTL( vblwait, (drm_wait_vblank_t *)data,
				  sizeof(vblwait) );

	switch ( vblwait.request.type & ~_DRM_VBLANK_FLAGS_MASK ) {
	case _DRM_VBLANK_RELATIVE:
		vblwait.request.sequence += atomic_read( &dev->vbl_received );
		vblwait.request.type &= ~_DRM_VBLANK_RELATIVE;
	case _DRM_VBLANK_ABSOLUTE:
		break;
	default:
		return -EINVAL;
	}

	flags = vblwait.request.type & _DRM_VBLANK_FLAGS_MASK;
	
	if ( flags & _DRM_VBLANK_SIGNAL ) {
		unsigned long irqflags;
		drm_vbl_sig_t *vbl_sig;
		
		vblwait.reply.sequence = atomic_read( &dev->vbl_received );

		spin_lock_irqsave( &dev->vbl_lock, irqflags );

		/* Check if this task has already scheduled the same signal
		 * for the same vblank sequence number; nothing to be done in
		 * that case
		 */
		list_for_each( ( (struct list_head *) vbl_sig ), &dev->vbl_sigs.head ) {
			if (vbl_sig->sequence == vblwait.request.sequence
			    && vbl_sig->info.si_signo == vblwait.request.signal
			    && vbl_sig->task == current)
			{
				spin_unlock_irqrestore( &dev->vbl_lock, irqflags );
				goto done;
			}
		}

		if ( dev->vbl_pending >= 100 ) {
			spin_unlock_irqrestore( &dev->vbl_lock, irqflags );
			return -EBUSY;
		}

		dev->vbl_pending++;

		spin_unlock_irqrestore( &dev->vbl_lock, irqflags );

		if ( !( vbl_sig = kmalloc(sizeof(drm_vbl_sig_t), GFP_KERNEL) ) ) 
			return -ENOMEM;
		

		memset( (void *)vbl_sig, 0, sizeof(*vbl_sig) );

		vbl_sig->sequence = vblwait.request.sequence;
		vbl_sig->info.si_signo = vblwait.request.signal;
		vbl_sig->task = current;

		spin_lock_irqsave( &dev->vbl_lock, irqflags );

		list_add_tail( (struct list_head *) vbl_sig, &dev->vbl_sigs.head );

		spin_unlock_irqrestore( &dev->vbl_lock, irqflags );
	} else {
		ret = DRM(vblank_wait)( dev, &vblwait.request.sequence );

		do_gettimeofday( &now );
		vblwait.reply.tval_sec = now.tv_sec;
		vblwait.reply.tval_usec = now.tv_usec;
	}

done:
	DRM_COPY_TO_USER_IOCTL( (drm_wait_vblank_t *)data, vblwait,
				sizeof(vblwait) );

	return ret;
}

void DRM(vbl_send_signals)( drm_device_t *dev )
{
	struct list_head *tmp;
	drm_vbl_sig_t *vbl_sig;
	unsigned int vbl_seq = atomic_read( &dev->vbl_received );
	unsigned long flags;

	spin_lock_irqsave( &dev->vbl_lock, flags );

	list_for_each_safe( ( (struct list_head *) vbl_sig ), tmp, &dev->vbl_sigs.head ) {
		if ( ( vbl_seq - vbl_sig->sequence ) <= (1<<23) ) {
			vbl_sig->info.si_code = vbl_seq;
			send_sig_info( vbl_sig->info.si_signo, &vbl_sig->info, vbl_sig->task );

			list_del( (struct list_head *) vbl_sig );


			kfree( vbl_sig );
			dev->vbl_pending--;
		}
	}

	spin_unlock_irqrestore( &dev->vbl_lock, flags );
}

#endif	/* __HAVE_VBL_IRQ */

#else

int DRM(control)( struct inode *inode, struct file *filp,
		  unsigned int cmd, unsigned long arg )
{
	drm_control_t ctl;

	if ( copy_from_user( &ctl, (drm_control_t *)arg, sizeof(ctl) ) )
		return -EFAULT;

	switch ( ctl.func ) {
	case DRM_INST_HANDLER:
	case DRM_UNINST_HANDLER:
		return 0;
	default:
		return -EINVAL;
	}
}

#endif /* __HAVE_DMA_IRQ */

#endif /* __HAVE_DMA */