gamma_dma.c

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

			retcode = -EINVAL;
			goto cleanup;
		}
		buf->pending = 1;

		if (dev->last_context != buf->context
		    && !(dev->queuelist[buf->context]->flags
			 & _DRM_CONTEXT_PRESERVED)) {
			add_wait_queue(&dev->context_wait, &entry);
			current->state = TASK_INTERRUPTIBLE;
				/* PRE: dev->last_context != buf->context */
			DRM(context_switch)(dev, dev->last_context,
					    buf->context);
				/* POST: we will wait for the context
				   switch and will dispatch on a later call
				   when dev->last_context == buf->context.
				   NOTE WE HOLD THE LOCK THROUGHOUT THIS
				   TIME! */
			schedule();
			current->state = TASK_RUNNING;
			remove_wait_queue(&dev->context_wait, &entry);
			if (signal_pending(current)) {
				retcode = -EINTR;
				goto cleanup;
			}
			if (dev->last_context != buf->context) {
				DRM_ERROR("Context mismatch: %d %d\n",
					  dev->last_context,
					  buf->context);
			}
		}

#if DRM_DMA_HISTOGRAM
		buf->time_queued     = get_cycles();
		buf->time_dispatched = buf->time_queued;
#endif
		gamma_dma_dispatch(dev, address, length);
		atomic_inc(&dev->counts[9]); /* _DRM_STAT_SPECIAL */
		atomic_add(length, &dev->counts[8]); /* _DRM_STAT_PRIMARY */

		if (last_buf) {
			gamma_free_buffer(dev, last_buf);
		}
		last_buf = buf;
	}


cleanup:
	if (last_buf) {
		gamma_dma_ready(dev);
		gamma_free_buffer(dev, last_buf);
	}

	if (must_free && !dev->context_flag) {
		if (gamma_lock_free(dev, &dev->lock.hw_lock->lock,
				  DRM_KERNEL_CONTEXT)) {
			DRM_ERROR("\n");
		}
	}
	clear_bit(0, &dev->interrupt_flag);
	return retcode;
}

static int gamma_dma_send_buffers(drm_device_t *dev, drm_dma_t *d)
{
	DECLARE_WAITQUEUE(entry, current);
	drm_buf_t	  *last_buf = NULL;
	int		  retcode   = 0;
	drm_device_dma_t  *dma	    = dev->dma;

	if (d->flags & _DRM_DMA_BLOCK) {
		last_buf = dma->buflist[d->send_indices[d->send_count-1]];
		add_wait_queue(&last_buf->dma_wait, &entry);
	}

	if ((retcode = gamma_dma_enqueue(dev, d))) {
		if (d->flags & _DRM_DMA_BLOCK)
			remove_wait_queue(&last_buf->dma_wait, &entry);
		return retcode;
	}

	gamma_dma_schedule(dev, 0);

	if (d->flags & _DRM_DMA_BLOCK) {
		DRM_DEBUG("%d waiting\n", current->pid);
		for (;;) {
			current->state = TASK_INTERRUPTIBLE;
			if (!last_buf->waiting && !last_buf->pending)
				break; /* finished */
			schedule();
			if (signal_pending(current)) {
				retcode = -EINTR; /* Can't restart */
				break;
			}
		}
		current->state = TASK_RUNNING;
		DRM_DEBUG("%d running\n", current->pid);
		remove_wait_queue(&last_buf->dma_wait, &entry);
		if (!retcode
		    || (last_buf->list==DRM_LIST_PEND && !last_buf->pending)) {
			if (!waitqueue_active(&last_buf->dma_wait)) {
				gamma_free_buffer(dev, last_buf);
			}
		}
		if (retcode) {
			DRM_ERROR("ctx%d w%d p%d c%ld i%d l%d %d/%d\n",
				  d->context,
				  last_buf->waiting,
				  last_buf->pending,
				  (long)DRM_WAITCOUNT(dev, d->context),
				  last_buf->idx,
				  last_buf->list,
				  last_buf->pid,
				  current->pid);
		}
	}
	return retcode;
}

int gamma_dma(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_device_dma_t  *dma	    = dev->dma;
	int		  retcode   = 0;
	drm_dma_t	  d;

	if (copy_from_user(&d, (drm_dma_t *)arg, sizeof(d)))
		return -EFAULT;

	if (d.send_count < 0 || d.send_count > dma->buf_count) {
		DRM_ERROR("Process %d trying to send %d buffers (of %d max)\n",
			  current->pid, d.send_count, dma->buf_count);
		return -EINVAL;
	}

	if (d.request_count < 0 || d.request_count > dma->buf_count) {
		DRM_ERROR("Process %d trying to get %d buffers (of %d max)\n",
			  current->pid, d.request_count, dma->buf_count);
		return -EINVAL;
	}

	if (d.send_count) {
		if (d.flags & _DRM_DMA_PRIORITY)
			retcode = gamma_dma_priority(dev, &d);
		else
			retcode = gamma_dma_send_buffers(dev, &d);
	}

	d.granted_count = 0;

	if (!retcode && d.request_count) {
		retcode = gamma_dma_get_buffers(dev, &d);
	}

	DRM_DEBUG("%d returning, granted = %d\n",
		  current->pid, d.granted_count);
	if (copy_to_user((drm_dma_t *)arg, &d, sizeof(d)))
		return -EFAULT;

	return retcode;
}

/* =============================================================
 * DMA initialization, cleanup
 */

static int gamma_do_init_dma( drm_device_t *dev, drm_gamma_init_t *init )
{
	drm_gamma_private_t *dev_priv;
	drm_device_dma_t    *dma = dev->dma;
	drm_buf_t	    *buf;
	int i;
	struct list_head    *list;
	unsigned long	    *pgt;

	DRM_DEBUG( "%s\n", __FUNCTION__ );

	dev_priv = DRM(alloc)( sizeof(drm_gamma_private_t),
							DRM_MEM_DRIVER );
	if ( !dev_priv )
		return -ENOMEM;

	dev->dev_private = (void *)dev_priv;

	memset( dev_priv, 0, sizeof(drm_gamma_private_t) );

	list_for_each(list, &dev->maplist->head) {
		#warning list_entry() is needed here
		drm_map_list_t *r_list = (drm_map_list_t *)list;
		if( r_list->map &&
		    r_list->map->type == _DRM_SHM &&
		    r_list->map->flags & _DRM_CONTAINS_LOCK ) {
			dev_priv->sarea = r_list->map;
 			break;
 		}
 	}

	DRM_FIND_MAP( dev_priv->mmio0, init->mmio0 );
	DRM_FIND_MAP( dev_priv->mmio1, init->mmio1 );
	DRM_FIND_MAP( dev_priv->mmio2, init->mmio2 );
	DRM_FIND_MAP( dev_priv->mmio3, init->mmio3 );

	dev_priv->sarea_priv = (drm_gamma_sarea_t *)
		((u8 *)dev_priv->sarea->handle +
		 init->sarea_priv_offset);

	if (init->pcimode) {
		buf = dma->buflist[GLINT_DRI_BUF_COUNT];
		pgt = buf->address;

 		for (i = 0; i < GLINT_DRI_BUF_COUNT; i++) {
			buf = dma->buflist[i];
			*pgt = virt_to_phys((void*)buf->address) | 0x07;
			pgt++;
		}

		buf = dma->buflist[GLINT_DRI_BUF_COUNT];
	} else {
		DRM_FIND_MAP( dev_priv->buffers, init->buffers_offset );

		DRM_IOREMAP( dev_priv->buffers );

		buf = dma->buflist[GLINT_DRI_BUF_COUNT];
		pgt = buf->address;

 		for (i = 0; i < GLINT_DRI_BUF_COUNT; i++) {
			buf = dma->buflist[i];
			*pgt = (unsigned long)buf->address + 0x07;
			pgt++;
		}

		buf = dma->buflist[GLINT_DRI_BUF_COUNT];

		while (GAMMA_READ(GAMMA_INFIFOSPACE) < 1);
		GAMMA_WRITE( GAMMA_GDMACONTROL, 0xe) cpu_relax();
	}
	while (GAMMA_READ(GAMMA_INFIFOSPACE) < 2); cpu_relax();
	GAMMA_WRITE( GAMMA_PAGETABLEADDR, virt_to_phys((void*)buf->address) );
	GAMMA_WRITE( GAMMA_PAGETABLELENGTH, 2 );

	return 0;
}

int gamma_do_cleanup_dma( drm_device_t *dev )
{
	DRM_DEBUG( "%s\n", __FUNCTION__ );

	if ( dev->dev_private ) {
		drm_gamma_private_t *dev_priv = dev->dev_private;

		DRM_IOREMAPFREE( dev_priv->buffers );

		DRM(free)( dev->dev_private, sizeof(drm_gamma_private_t),
			   DRM_MEM_DRIVER );
		dev->dev_private = NULL;
	}

	return 0;
}

int gamma_dma_init( 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_gamma_init_t init;

	if ( copy_from_user( &init, (drm_gamma_init_t *)arg, sizeof(init) ) )
		return -EFAULT;

	switch ( init.func ) {
	case GAMMA_INIT_DMA:
		return gamma_do_init_dma( dev, &init );
	case GAMMA_CLEANUP_DMA:
		return gamma_do_cleanup_dma( dev );
	}

	return -EINVAL;
}

static int gamma_do_copy_dma( drm_device_t *dev, drm_gamma_copy_t *copy )
{
	drm_device_dma_t    *dma = dev->dma;
	unsigned int        *screenbuf;

	DRM_DEBUG( "%s\n", __FUNCTION__ );

	/* We've DRM_RESTRICTED this DMA buffer */

	screenbuf = dma->buflist[ GLINT_DRI_BUF_COUNT + 1 ]->address;

#if 0
	*buffer++ = 0x180;	/* Tag (FilterMode) */
	*buffer++ = 0x200;	/* Allow FBColor through */
	*buffer++ = 0x53B;	/* Tag */
	*buffer++ = copy->Pitch;
	*buffer++ = 0x53A;	/* Tag */
	*buffer++ = copy->SrcAddress;
	*buffer++ = 0x539;	/* Tag */
	*buffer++ = copy->WidthHeight; /* Initiates transfer */
	*buffer++ = 0x53C;	/* Tag - DMAOutputAddress */
	*buffer++ = virt_to_phys((void*)screenbuf);
	*buffer++ = 0x53D;	/* Tag - DMAOutputCount */
	*buffer++ = copy->Count; /* Reads HostOutFifo BLOCKS until ..*/

	/* Data now sitting in dma->buflist[ GLINT_DRI_BUF_COUNT + 1 ] */
	/* Now put it back to the screen */

	*buffer++ = 0x180;	/* Tag (FilterMode) */
	*buffer++ = 0x400;	/* Allow Sync through */
	*buffer++ = 0x538;	/* Tag - DMARectangleReadTarget */
	*buffer++ = 0x155;	/* FBSourceData | count */
	*buffer++ = 0x537;	/* Tag */
	*buffer++ = copy->Pitch;
	*buffer++ = 0x536;	/* Tag */
	*buffer++ = copy->DstAddress;
	*buffer++ = 0x535;	/* Tag */
	*buffer++ = copy->WidthHeight; /* Initiates transfer */
	*buffer++ = 0x530;	/* Tag - DMAAddr */
	*buffer++ = virt_to_phys((void*)screenbuf);
	*buffer++ = 0x531;
	*buffer++ = copy->Count; /* initiates DMA transfer of color data */
#endif

	/* need to dispatch it now */

	return 0;
}

int gamma_dma_copy( 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_gamma_copy_t copy;

	if ( copy_from_user( &copy, (drm_gamma_copy_t *)arg, sizeof(copy) ) )
		return -EFAULT;

	return gamma_do_copy_dma( dev, &copy );
}

/* =============================================================
 * Per Context SAREA Support
 */

int gamma_getsareactx(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_ctx_priv_map_t request;
	drm_map_t *map;

	if (copy_from_user(&request,
			   (drm_ctx_priv_map_t *)arg,
			   sizeof(request)))
		return -EFAULT;

	down(&dev->struct_sem);
	if ((int)request.ctx_id >= dev->max_context) {
		up(&dev->struct_sem);
		return -EINVAL;
	}

	map = dev->context_sareas[request.ctx_id];
	up(&dev->struct_sem);

	request.handle = map->handle;
	if (copy_to_user((drm_ctx_priv_map_t *)arg, &request, sizeof(request)))
		return -EFAULT;
	return 0;
}

int gamma_setsareactx(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_ctx_priv_map_t request;
	drm_map_t *map = NULL;
	drm_map_list_t *r_list;
	struct list_head *list;

	if (copy_from_user(&request,
			   (drm_ctx_priv_map_t *)arg,
			   sizeof(request)))
		return -EFAULT;

	down(&dev->struct_sem);
	r_list = NULL;
	list_for_each(list, &dev->maplist->head) {
		r_list = (drm_map_list_t *)list;
		if(r_list->map &&
		   r_list->map->handle == request.handle) break;
	}
	if (list == &(dev->maplist->head)) {
		up(&dev->struct_sem);
		return -EINVAL;
	}
	map = r_list->map;
	up(&dev->struct_sem);

	if (!map) return -EINVAL;

	down(&dev->struct_sem);
	if ((int)request.ctx_id >= dev->max_context) {
		up(&dev->struct_sem);
		return -EINVAL;
	}
	dev->context_sareas[request.ctx_id] = map;
	up(&dev->struct_sem);
	return 0;
}