linux-next/drivers/gpu/drm/drm_drv.c

/**
 * \file drm_drv.c
 * Generic driver template
 *
 * \author Rickard E. (Rik) Faith <faith@valinux.com>
 * \author Gareth Hughes <gareth@valinux.com>
 *
 * To use this template, you must at least define the following (samples
 * given for the MGA driver):
 *
 * \code
 * #define DRIVER_AUTHOR	"VA Linux Systems, Inc."
 *
 * #define DRIVER_NAME		"mga"
 * #define DRIVER_DESC		"Matrox G200/G400"
 * #define DRIVER_DATE		"20001127"
 *
 * #define drm_x		mga_##x
 * \endcode
 */

/*
 * 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 "drmP.h"
#include "drm_core.h"

static int drm_version(struct drm_device *dev, void *data,
		       struct drm_file *file_priv);

/** Ioctl table */
static struct drm_ioctl_desc drm_ioctls[] = {
	DRM_IOCTL_DEF(DRM_IOCTL_VERSION, drm_version, 0),
	DRM_IOCTL_DEF(DRM_IOCTL_GET_UNIQUE, drm_getunique, 0),
	DRM_IOCTL_DEF(DRM_IOCTL_GET_MAGIC, drm_getmagic, 0),
	DRM_IOCTL_DEF(DRM_IOCTL_IRQ_BUSID, drm_irq_by_busid, DRM_MASTER|DRM_ROOT_ONLY),
	DRM_IOCTL_DEF(DRM_IOCTL_GET_MAP, drm_getmap, 0),
	DRM_IOCTL_DEF(DRM_IOCTL_GET_CLIENT, drm_getclient, 0),
	DRM_IOCTL_DEF(DRM_IOCTL_GET_STATS, drm_getstats, 0),
	DRM_IOCTL_DEF(DRM_IOCTL_SET_VERSION, drm_setversion, DRM_MASTER|DRM_ROOT_ONLY),

	DRM_IOCTL_DEF(DRM_IOCTL_SET_UNIQUE, drm_setunique, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
	DRM_IOCTL_DEF(DRM_IOCTL_BLOCK, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
	DRM_IOCTL_DEF(DRM_IOCTL_UNBLOCK, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
	DRM_IOCTL_DEF(DRM_IOCTL_AUTH_MAGIC, drm_authmagic, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),

	DRM_IOCTL_DEF(DRM_IOCTL_ADD_MAP, drm_addmap_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
	DRM_IOCTL_DEF(DRM_IOCTL_RM_MAP, drm_rmmap_ioctl, DRM_AUTH),

	DRM_IOCTL_DEF(DRM_IOCTL_SET_SAREA_CTX, drm_setsareactx, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
	DRM_IOCTL_DEF(DRM_IOCTL_GET_SAREA_CTX, drm_getsareactx, DRM_AUTH),

	DRM_IOCTL_DEF(DRM_IOCTL_SET_MASTER, drm_setmaster_ioctl, DRM_ROOT_ONLY),
	DRM_IOCTL_DEF(DRM_IOCTL_DROP_MASTER, drm_dropmaster_ioctl, DRM_ROOT_ONLY),

	DRM_IOCTL_DEF(DRM_IOCTL_ADD_CTX, drm_addctx, DRM_AUTH|DRM_ROOT_ONLY),
	DRM_IOCTL_DEF(DRM_IOCTL_RM_CTX, drm_rmctx, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
	DRM_IOCTL_DEF(DRM_IOCTL_MOD_CTX, drm_modctx, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
	DRM_IOCTL_DEF(DRM_IOCTL_GET_CTX, drm_getctx, DRM_AUTH),
	DRM_IOCTL_DEF(DRM_IOCTL_SWITCH_CTX, drm_switchctx, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
	DRM_IOCTL_DEF(DRM_IOCTL_NEW_CTX, drm_newctx, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
	DRM_IOCTL_DEF(DRM_IOCTL_RES_CTX, drm_resctx, DRM_AUTH),

	DRM_IOCTL_DEF(DRM_IOCTL_ADD_DRAW, drm_adddraw, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
	DRM_IOCTL_DEF(DRM_IOCTL_RM_DRAW, drm_rmdraw, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),

	DRM_IOCTL_DEF(DRM_IOCTL_LOCK, drm_lock, DRM_AUTH),
	DRM_IOCTL_DEF(DRM_IOCTL_UNLOCK, drm_unlock, DRM_AUTH),

	DRM_IOCTL_DEF(DRM_IOCTL_FINISH, drm_noop, DRM_AUTH),

	DRM_IOCTL_DEF(DRM_IOCTL_ADD_BUFS, drm_addbufs, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
	DRM_IOCTL_DEF(DRM_IOCTL_MARK_BUFS, drm_markbufs, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
	DRM_IOCTL_DEF(DRM_IOCTL_INFO_BUFS, drm_infobufs, DRM_AUTH),
	DRM_IOCTL_DEF(DRM_IOCTL_MAP_BUFS, drm_mapbufs, DRM_AUTH),
	DRM_IOCTL_DEF(DRM_IOCTL_FREE_BUFS, drm_freebufs, DRM_AUTH),
	/* The DRM_IOCTL_DMA ioctl should be defined by the driver. */
	DRM_IOCTL_DEF(DRM_IOCTL_DMA, NULL, DRM_AUTH),

	DRM_IOCTL_DEF(DRM_IOCTL_CONTROL, drm_control, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),

#if __OS_HAS_AGP
	DRM_IOCTL_DEF(DRM_IOCTL_AGP_ACQUIRE, drm_agp_acquire_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
	DRM_IOCTL_DEF(DRM_IOCTL_AGP_RELEASE, drm_agp_release_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
	DRM_IOCTL_DEF(DRM_IOCTL_AGP_ENABLE, drm_agp_enable_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
	DRM_IOCTL_DEF(DRM_IOCTL_AGP_INFO, drm_agp_info_ioctl, DRM_AUTH),
	DRM_IOCTL_DEF(DRM_IOCTL_AGP_ALLOC, drm_agp_alloc_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
	DRM_IOCTL_DEF(DRM_IOCTL_AGP_FREE, drm_agp_free_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
	DRM_IOCTL_DEF(DRM_IOCTL_AGP_BIND, drm_agp_bind_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
	DRM_IOCTL_DEF(DRM_IOCTL_AGP_UNBIND, drm_agp_unbind_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
#endif

	DRM_IOCTL_DEF(DRM_IOCTL_SG_ALLOC, drm_sg_alloc_ioctl, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),
	DRM_IOCTL_DEF(DRM_IOCTL_SG_FREE, drm_sg_free, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),

	DRM_IOCTL_DEF(DRM_IOCTL_WAIT_VBLANK, drm_wait_vblank, 0),

	DRM_IOCTL_DEF(DRM_IOCTL_MODESET_CTL, drm_modeset_ctl, 0),

	DRM_IOCTL_DEF(DRM_IOCTL_UPDATE_DRAW, drm_update_drawable_info, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY),

	DRM_IOCTL_DEF(DRM_IOCTL_GEM_CLOSE, drm_gem_close_ioctl, 0),
	DRM_IOCTL_DEF(DRM_IOCTL_GEM_FLINK, drm_gem_flink_ioctl, DRM_AUTH),
	DRM_IOCTL_DEF(DRM_IOCTL_GEM_OPEN, drm_gem_open_ioctl, DRM_AUTH),

	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETRESOURCES, drm_mode_getresources, DRM_MASTER|DRM_CONTROL_ALLOW),
	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETCRTC, drm_mode_getcrtc, DRM_MASTER|DRM_CONTROL_ALLOW),
	DRM_IOCTL_DEF(DRM_IOCTL_MODE_SETCRTC, drm_mode_setcrtc, DRM_MASTER|DRM_CONTROL_ALLOW),
	DRM_IOCTL_DEF(DRM_IOCTL_MODE_CURSOR, drm_mode_cursor_ioctl, DRM_MASTER|DRM_CONTROL_ALLOW),
	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETGAMMA, drm_mode_gamma_get_ioctl, DRM_MASTER),
	DRM_IOCTL_DEF(DRM_IOCTL_MODE_SETGAMMA, drm_mode_gamma_set_ioctl, DRM_MASTER),
	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETENCODER, drm_mode_getencoder, DRM_MASTER|DRM_CONTROL_ALLOW),
	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETCONNECTOR, drm_mode_getconnector, DRM_MASTER|DRM_CONTROL_ALLOW),
	DRM_IOCTL_DEF(DRM_IOCTL_MODE_ATTACHMODE, drm_mode_attachmode_ioctl, DRM_MASTER|DRM_CONTROL_ALLOW),
	DRM_IOCTL_DEF(DRM_IOCTL_MODE_DETACHMODE, drm_mode_detachmode_ioctl, DRM_MASTER|DRM_CONTROL_ALLOW),
	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETPROPERTY, drm_mode_getproperty_ioctl, DRM_MASTER | DRM_CONTROL_ALLOW),
	DRM_IOCTL_DEF(DRM_IOCTL_MODE_SETPROPERTY, drm_mode_connector_property_set_ioctl, DRM_MASTER|DRM_CONTROL_ALLOW),
	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETPROPBLOB, drm_mode_getblob_ioctl, DRM_MASTER|DRM_CONTROL_ALLOW),
	DRM_IOCTL_DEF(DRM_IOCTL_MODE_GETFB, drm_mode_getfb, DRM_MASTER|DRM_CONTROL_ALLOW),
	DRM_IOCTL_DEF(DRM_IOCTL_MODE_ADDFB, drm_mode_addfb, DRM_MASTER|DRM_CONTROL_ALLOW),
	DRM_IOCTL_DEF(DRM_IOCTL_MODE_RMFB, drm_mode_rmfb, DRM_MASTER|DRM_CONTROL_ALLOW),
};

#define DRM_CORE_IOCTL_COUNT	ARRAY_SIZE( drm_ioctls )

/**
 * Take down the DRM device.
 *
 * \param dev DRM device structure.
 *
 * Frees every resource in \p dev.
 *
 * \sa drm_device
 */
int drm_lastclose(struct drm_device * dev)
{
	struct drm_vma_entry *vma, *vma_temp;
	int i;

	DRM_DEBUG("\n");

	if (dev->driver->lastclose)
		dev->driver->lastclose(dev);
	DRM_DEBUG("driver lastclose completed\n");

	if (dev->irq_enabled && !drm_core_check_feature(dev, DRIVER_MODESET))
		drm_irq_uninstall(dev);

	mutex_lock(&dev->struct_mutex);

	/* Free drawable information memory */
	drm_drawable_free_all(dev);
	del_timer(&dev->timer);

	/* Clear AGP information */
	if (drm_core_has_AGP(dev) && dev->agp &&
	    !drm_core_check_feature(dev, DRIVER_MODESET)) {
		struct drm_agp_mem *entry, *tempe;

		/* Remove AGP resources, but leave dev->agp
		   intact until drv_cleanup is called. */
		list_for_each_entry_safe(entry, tempe, &dev->agp->memory, head) {
			if (entry->bound)
				drm_unbind_agp(entry->memory);
			drm_free_agp(entry->memory, entry->pages);
			drm_free(entry, sizeof(*entry), DRM_MEM_AGPLISTS);
		}
		INIT_LIST_HEAD(&dev->agp->memory);

		if (dev->agp->acquired)
			drm_agp_release(dev);

		dev->agp->acquired = 0;
		dev->agp->enabled = 0;
	}
	if (drm_core_check_feature(dev, DRIVER_SG) && dev->sg &&
	    !drm_core_check_feature(dev, DRIVER_MODESET)) {
		drm_sg_cleanup(dev->sg);
		dev->sg = NULL;
	}

	/* Clear vma list (only built for debugging) */
	list_for_each_entry_safe(vma, vma_temp, &dev->vmalist, head) {
		list_del(&vma->head);
		drm_free(vma, sizeof(*vma), DRM_MEM_VMAS);
	}

	if (drm_core_check_feature(dev, DRIVER_DMA_QUEUE) && dev->queuelist) {
		for (i = 0; i < dev->queue_count; i++) {
			if (dev->queuelist[i]) {
				drm_free(dev->queuelist[i],
					 sizeof(*dev->queuelist[0]),
					 DRM_MEM_QUEUES);
				dev->queuelist[i] = NULL;
			}
		}
		drm_free(dev->queuelist,
			 dev->queue_slots * sizeof(*dev->queuelist),
			 DRM_MEM_QUEUES);
		dev->queuelist = NULL;
	}
	dev->queue_count = 0;

	if (drm_core_check_feature(dev, DRIVER_HAVE_DMA) &&
	    !drm_core_check_feature(dev, DRIVER_MODESET))
		drm_dma_takedown(dev);

	dev->dev_mapping = NULL;
	mutex_unlock(&dev->struct_mutex);

	DRM_DEBUG("lastclose completed\n");
	return 0;
}

/**
 * Module initialization. Called via init_module at module load time, or via
 * linux/init/main.c (this is not currently supported).
 *
 * \return zero on success or a negative number on failure.
 *
 * Initializes an array of drm_device structures, and attempts to
 * initialize all available devices, using consecutive minors, registering the
 * stubs and initializing the AGP device.
 *
 * Expands the \c DRIVER_PREINIT and \c DRIVER_POST_INIT macros before and
 * after the initialization for driver customization.
 */
int drm_init(struct drm_driver *driver)
{
	struct pci_dev *pdev = NULL;
	const struct pci_device_id *pid;
	int i;

	DRM_DEBUG("\n");

	INIT_LIST_HEAD(&driver->device_list);

	if (driver->driver_features & DRIVER_MODESET)
		return pci_register_driver(&driver->pci_driver);

	/* If not using KMS, fall back to stealth mode manual scanning. */
	for (i = 0; driver->pci_driver.id_table[i].vendor != 0; i++) {
		pid = &driver->pci_driver.id_table[i];

		/* Loop around setting up a DRM device for each PCI device
		 * matching our ID and device class.  If we had the internal
		 * function that pci_get_subsys and pci_get_class used, we'd
		 * be able to just pass pid in instead of doing a two-stage
		 * thing.
		 */
		pdev = NULL;
		while ((pdev =
			pci_get_subsys(pid->vendor, pid->device, pid->subvendor,
				       pid->subdevice, pdev)) != NULL) {
			if ((pdev->class & pid->class_mask) != pid->class)
				continue;

			/* stealth mode requires a manual probe */
			pci_dev_get(pdev);
			drm_get_dev(pdev, pid, driver);
		}
	}
	return 0;
}

EXPORT_SYMBOL(drm_init);

void drm_exit(struct drm_driver *driver)
{
	struct drm_device *dev, *tmp;
	DRM_DEBUG("\n");

	if (driver->driver_features & DRIVER_MODESET) {
		pci_unregister_driver(&driver->pci_driver);
	} else {
		list_for_each_entry_safe(dev, tmp, &driver->device_list, driver_item)
			drm_put_dev(dev);
	}

	DRM_INFO("Module unloaded\n");
}

EXPORT_SYMBOL(drm_exit);

/** File operations structure */
static const struct file_operations drm_stub_fops = {
	.owner = THIS_MODULE,
	.open = drm_stub_open
};

static int __init drm_core_init(void)
{
	int ret = -ENOMEM;

	idr_init(&drm_minors_idr);

	if (register_chrdev(DRM_MAJOR, "drm", &drm_stub_fops))
		goto err_p1;

	drm_class = drm_sysfs_create(THIS_MODULE, "drm");
	if (IS_ERR(drm_class)) {
		printk(KERN_ERR "DRM: Error creating drm class.\n");
		ret = PTR_ERR(drm_class);
		goto err_p2;
	}

	drm_proc_root = proc_mkdir("dri", NULL);
	if (!drm_proc_root) {
		DRM_ERROR("Cannot create /proc/dri\n");
		ret = -1;
		goto err_p3;
	}

	drm_mem_init();

	DRM_INFO("Initialized %s %d.%d.%d %s\n",
		 CORE_NAME, CORE_MAJOR, CORE_MINOR, CORE_PATCHLEVEL, CORE_DATE);
	return 0;
err_p3:
	drm_sysfs_destroy();
err_p2:
	unregister_chrdev(DRM_MAJOR, "drm");

	idr_destroy(&drm_minors_idr);
err_p1:
	return ret;
}

static void __exit drm_core_exit(void)
{
	remove_proc_entry("dri", NULL);
	drm_sysfs_destroy();

	unregister_chrdev(DRM_MAJOR, "drm");

	idr_destroy(&drm_minors_idr);
}

module_init(drm_core_init);
module_exit(drm_core_exit);

/**
 * Get version information
 *
 * \param inode device inode.
 * \param filp file pointer.
 * \param cmd command.
 * \param arg user argument, pointing to a drm_version structure.
 * \return zero on success or negative number on failure.
 *
 * Fills in the version information in \p arg.
 */
static int drm_version(struct drm_device *dev, void *data,
		       struct drm_file *file_priv)
{
	struct drm_version *version = data;
	int len;

	version->version_major = dev->driver->major;
	version->version_minor = dev->driver->minor;
	version->version_patchlevel = dev->driver->patchlevel;
	DRM_COPY(version->name, dev->driver->name);
	DRM_COPY(version->date, dev->driver->date);
	DRM_COPY(version->desc, dev->driver->desc);

	return 0;
}

/**
 * Called whenever a process performs an ioctl on /dev/drm.
 *
 * \param inode device inode.
 * \param file_priv DRM file private.
 * \param cmd command.
 * \param arg user argument.
 * \return zero on success or negative number on failure.
 *
 * Looks up the ioctl function in the ::ioctls table, checking for root
 * previleges if so required, and dispatches to the respective function.
 */
int drm_ioctl(struct inode *inode, struct file *filp,
	      unsigned int cmd, unsigned long arg)
{
	struct drm_file *file_priv = filp->private_data;
	struct drm_device *dev = file_priv->minor->dev;
	struct drm_ioctl_desc *ioctl;
	drm_ioctl_t *func;
	unsigned int nr = DRM_IOCTL_NR(cmd);
	int retcode = -EINVAL;
	char *kdata = NULL;

	atomic_inc(&dev->ioctl_count);
	atomic_inc(&dev->counts[_DRM_STAT_IOCTLS]);
	++file_priv->ioctl_count;

	DRM_DEBUG("pid=%d, cmd=0x%02x, nr=0x%02x, dev 0x%lx, auth=%d\n",
		  task_pid_nr(current), cmd, nr,
		  (long)old_encode_dev(file_priv->minor->device),
		  file_priv->authenticated);

	if ((nr >= DRM_CORE_IOCTL_COUNT) &&
	    ((nr < DRM_COMMAND_BASE) || (nr >= DRM_COMMAND_END)))
		goto err_i1;
	if ((nr >= DRM_COMMAND_BASE) && (nr < DRM_COMMAND_END) &&
	    (nr < DRM_COMMAND_BASE + dev->driver->num_ioctls))
		ioctl = &dev->driver->ioctls[nr - DRM_COMMAND_BASE];
	else if ((nr >= DRM_COMMAND_END) || (nr < DRM_COMMAND_BASE)) {
		ioctl = &drm_ioctls[nr];
		cmd = ioctl->cmd;
	} else
		goto err_i1;

	/* Do not trust userspace, use our own definition */
	func = ioctl->func;
	/* is there a local override? */
	if ((nr == DRM_IOCTL_NR(DRM_IOCTL_DMA)) && dev->driver->dma_ioctl)
		func = dev->driver->dma_ioctl;

	if (!func) {
		DRM_DEBUG("no function\n");
		retcode = -EINVAL;
	} else if (((ioctl->flags & DRM_ROOT_ONLY) && !capable(CAP_SYS_ADMIN)) ||
		   ((ioctl->flags & DRM_AUTH) && !file_priv->authenticated) ||
		   ((ioctl->flags & DRM_MASTER) && !file_priv->is_master)) {
		retcode = -EACCES;
	} else {
		if (cmd & (IOC_IN | IOC_OUT)) {
			kdata = kmalloc(_IOC_SIZE(cmd), GFP_KERNEL);
			if (!kdata) {
				retcode = -ENOMEM;
				goto err_i1;
			}
		}

		if (cmd & IOC_IN) {
			if (copy_from_user(kdata, (void __user *)arg,
					   _IOC_SIZE(cmd)) != 0) {
				retcode = -EFAULT;
				goto err_i1;
			}
		}
		retcode = func(dev, kdata, file_priv);

		if ((retcode == 0) && (cmd & IOC_OUT)) {
			if (copy_to_user((void __user *)arg, kdata,
					 _IOC_SIZE(cmd)) != 0)
				retcode = -EFAULT;
		}
	}

      err_i1:
	if (kdata)
		kfree(kdata);
	atomic_dec(&dev->ioctl_count);
	if (retcode)
		DRM_DEBUG("ret = %x\n", retcode);
	return retcode;
}

EXPORT_SYMBOL(drm_ioctl);

struct drm_local_map *drm_getsarea(struct drm_device *dev)
{
	struct drm_map_list *entry;

	list_for_each_entry(entry, &dev->maplist, head) {
		if (entry->map && entry->map->type == _DRM_SHM &&
		    (entry->map->flags & _DRM_CONTAINS_LOCK)) {
			return entry->map;
		}
	}
	return NULL;
}
EXPORT_SYMBOL(drm_getsarea);