path: root/drivers/char/drm/drm_bufs.c

/**
 * \file drm_bufs.h 
 * Generic buffer template
 * 
 * \author Rickard E. (Rik) Faith <faith@valinux.com>
 * \author Gareth Hughes <gareth@valinux.com>
 */

/*
 * Created: Thu Nov 23 03:10:50 2000 by gareth@valinux.com
 *
 * Copyright 1999, 2000 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.
 */

#include <linux/vmalloc.h>
#include "drmP.h"

/**
 * Compute size order.  Returns the exponent of the smaller power of two which
 * is greater or equal to given number.
 * 
 * \param size size.
 * \return order.
 *
 * \todo Can be made faster.
 */
int drm_order( unsigned long size )
{
	int order;
	unsigned long tmp;

	for (order = 0, tmp = size >> 1; tmp; tmp >>= 1, order++)
		;

	if (size & (size - 1))
		++order;

	return order;
}
EXPORT_SYMBOL(drm_order);

/**
 * Ioctl to specify a range of memory that is available for mapping by a non-root process.
 *
 * \param inode device inode.
 * \param filp file pointer.
 * \param cmd command.
 * \param arg pointer to a drm_map structure.
 * \return zero on success or a negative value on error.
 *
 * Adjusts the memory offset to its absolute value according to the mapping
 * type.  Adds the map to the map list drm_device::maplist. Adds MTRR's where
 * applicable and if supported by the kernel.
 */
int drm_addmap( struct inode *inode, struct file *filp,
		 unsigned int cmd, unsigned long arg )
{
	drm_file_t *priv = filp->private_data;
	drm_device_t *dev = priv->head->dev;
	drm_map_t *map;
	drm_map_t __user *argp = (void __user *)arg;
	drm_map_list_t *list;

	if ( !(filp->f_mode & 3) ) return -EACCES; /* Require read/write */

	map = drm_alloc( sizeof(*map), DRM_MEM_MAPS );
	if ( !map )
		return -ENOMEM;

	if ( copy_from_user( map, argp, sizeof(*map) ) ) {
		drm_free( map, sizeof(*map), DRM_MEM_MAPS );
		return -EFAULT;
	}

	/* Only allow shared memory to be removable since we only keep enough
	 * book keeping information about shared memory to allow for removal
	 * when processes fork.
	 */
	if ( (map->flags & _DRM_REMOVABLE) && map->type != _DRM_SHM ) {
		drm_free( map, sizeof(*map), DRM_MEM_MAPS );
		return -EINVAL;
	}
	DRM_DEBUG( "offset = 0x%08lx, size = 0x%08lx, type = %d\n",<