drm_lock.c

Version: - FREEBSD - FREEBSD-13-STABLE - FREEBSD-13-0 - FREEBSD-12-STABLE - FREEBSD-12-0 - FREEBSD-11-STABLE - FREEBSD-11-0 - FREEBSD-10-STABLE - FREEBSD-10-0 - FREEBSD-9-STABLE - FREEBSD-9-0 - FREEBSD-8-STABLE - FREEBSD-8-0 - FREEBSD-7-STABLE - FREEBSD-7-0 - FREEBSD-6-STABLE - FREEBSD-6-0 - FREEBSD-5-STABLE - FREEBSD-5-0 - FREEBSD-4-STABLE - FREEBSD-3-STABLE - FREEBSD22 - l41 - OPENBSD - linux-2.6 - MK84 - PLAN9 - xnu-8792
SearchContext: - none - 3 - 10

    1 /*-
    2  * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
    3  * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
    4  * All Rights Reserved.
    5  *
    6  * Permission is hereby granted, free of charge, to any person obtaining a
    7  * copy of this software and associated documentation files (the "Software"),
    8  * to deal in the Software without restriction, including without limitation
    9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   10  * and/or sell copies of the Software, and to permit persons to whom the
   11  * Software is furnished to do so, subject to the following conditions:
   12  *
   13  * The above copyright notice and this permission notice (including the next
   14  * paragraph) shall be included in all copies or substantial portions of the
   15  * Software.
   16  *
   17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
   20  * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
   21  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
   22  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
   23  * OTHER DEALINGS IN THE SOFTWARE.
   24  *
   25  * Authors:
   26  *    Rickard E. (Rik) Faith <faith@valinux.com>
   27  *    Gareth Hughes <gareth@valinux.com>
   28  *
   29  */
   30 
   31 #include <sys/cdefs.h>
   32 __FBSDID("$FreeBSD: releng/9.0/sys/dev/drm/drm_lock.c 190023 2009-03-19 08:36:08Z rnoland $");
   33 
   34 /** @file drm_lock.c
   35  * Implementation of the ioctls and other support code for dealing with the
   36  * hardware lock.
   37  *
   38  * The DRM hardware lock is a shared structure between the kernel and userland.
   39  *
   40  * On uncontended access where the new context was the last context, the
   41  * client may take the lock without dropping down into the kernel, using atomic
   42  * compare-and-set.
   43  *
   44  * If the client finds during compare-and-set that it was not the last owner
   45  * of the lock, it calls the DRM lock ioctl, which may sleep waiting for the
   46  * lock, and may have side-effects of kernel-managed context switching.
   47  *
   48  * When the client releases the lock, if the lock is marked as being contended
   49  * by another client, then the DRM unlock ioctl is called so that the
   50  * contending client may be woken up.
   51  */
   52 
   53 #include "dev/drm/drmP.h"
   54 
   55 int drm_lock(struct drm_device *dev, void *data, struct drm_file *file_priv)
   56 {
   57         struct drm_lock *lock = data;
   58         int ret = 0;
   59 
   60         if (lock->context == DRM_KERNEL_CONTEXT) {
   61                 DRM_ERROR("Process %d using kernel context %d\n",
   62                     DRM_CURRENTPID, lock->context);
   63                 return EINVAL;
   64         }
   65 
   66         DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n",
   67             lock->context, DRM_CURRENTPID, dev->lock.hw_lock->lock,
   68             lock->flags);
   69 
   70         if (drm_core_check_feature(dev, DRIVER_DMA_QUEUE) &&
   71             lock->context < 0)
   72                 return EINVAL;
   73 
   74         DRM_LOCK();
   75         for (;;) {
   76                 if (drm_lock_take(&dev->lock, lock->context)) {
   77                         dev->lock.file_priv = file_priv;
   78                         dev->lock.lock_time = jiffies;
   79                         atomic_inc(&dev->counts[_DRM_STAT_LOCKS]);
   80                         break;  /* Got lock */
   81                 }
   82 
   83                 /* Contention */
   84                 ret = mtx_sleep((void *)&dev->lock.lock_queue, &dev->dev_lock,
   85                     PCATCH, "drmlk2", 0);
   86                 if (ret != 0)
   87                         break;
   88         }
   89         DRM_UNLOCK();
   90 
   91         if (ret == ERESTART)
   92                 DRM_DEBUG("restarting syscall\n");
   93         else
   94                 DRM_DEBUG("%d %s\n", lock->context,
   95                     ret ? "interrupted" : "has lock");
   96 
   97         if (ret != 0)
   98                 return ret;
   99 
  100         /* XXX: Add signal blocking here */
  101 
  102         if (dev->driver->dma_quiescent != NULL &&
  103             (lock->flags & _DRM_LOCK_QUIESCENT))
  104                 dev->driver->dma_quiescent(dev);
  105 
  106         return 0;
  107 }
  108 
  109 int drm_unlock(struct drm_device *dev, void *data, struct drm_file *file_priv)
  110 {
  111         struct drm_lock *lock = data;
  112 
  113         DRM_DEBUG("%d (pid %d) requests unlock (0x%08x), flags = 0x%08x\n",
  114             lock->context, DRM_CURRENTPID, dev->lock.hw_lock->lock,
  115             lock->flags);
  116 
  117         if (lock->context == DRM_KERNEL_CONTEXT) {
  118                 DRM_ERROR("Process %d using kernel context %d\n",
  119                     DRM_CURRENTPID, lock->context);
  120                 return EINVAL;
  121         }
  122 
  123         atomic_inc(&dev->counts[_DRM_STAT_UNLOCKS]);
  124 
  125         DRM_LOCK();
  126         drm_lock_transfer(&dev->lock, DRM_KERNEL_CONTEXT);
  127 
  128         if (drm_lock_free(&dev->lock, DRM_KERNEL_CONTEXT)) {
  129                 DRM_ERROR("\n");
  130         }
  131         DRM_UNLOCK();
  132 
  133         return 0;
  134 }
  135 
  136 int drm_lock_take(struct drm_lock_data *lock_data, unsigned int context)
  137 {
  138         volatile unsigned int *lock = &lock_data->hw_lock->lock;
  139         unsigned int old, new;
  140 
  141         do {
  142                 old = *lock;
  143                 if (old & _DRM_LOCK_HELD)
  144                         new = old | _DRM_LOCK_CONT;
  145                 else
  146                         new = context | _DRM_LOCK_HELD;
  147         } while (!atomic_cmpset_int(lock, old, new));
  148 
  149         if (_DRM_LOCKING_CONTEXT(old) == context) {
  150                 if (old & _DRM_LOCK_HELD) {
  151                         if (context != DRM_KERNEL_CONTEXT) {
  152                                 DRM_ERROR("%d holds heavyweight lock\n",
  153                                     context);
  154                         }
  155                         return 0;
  156                 }
  157         }
  158         if (new == (context | _DRM_LOCK_HELD)) {
  159                 /* Have lock */
  160                 return 1;
  161         }
  162         return 0;
  163 }
  164 
  165 /* This takes a lock forcibly and hands it to context.  Should ONLY be used
  166    inside *_unlock to give lock to kernel before calling *_dma_schedule. */
  167 int drm_lock_transfer(struct drm_lock_data *lock_data, unsigned int context)
  168 {
  169         volatile unsigned int *lock = &lock_data->hw_lock->lock;
  170         unsigned int old, new;
  171 
  172         lock_data->file_priv = NULL;
  173         do {
  174                 old = *lock;
  175                 new = context | _DRM_LOCK_HELD;
  176         } while (!atomic_cmpset_int(lock, old, new));
  177 
  178         return 1;
  179 }
  180 
  181 int drm_lock_free(struct drm_lock_data *lock_data, unsigned int context)
  182 {
  183         volatile unsigned int *lock = &lock_data->hw_lock->lock;
  184         unsigned int old, new;
  185 
  186         lock_data->file_priv = NULL;
  187         do {
  188                 old = *lock;
  189                 new = 0;
  190         } while (!atomic_cmpset_int(lock, old, new));
  191 
  192         if (_DRM_LOCK_IS_HELD(old) && _DRM_LOCKING_CONTEXT(old) != context) {
  193                 DRM_ERROR("%d freed heavyweight lock held by %d\n",
  194                     context, _DRM_LOCKING_CONTEXT(old));
  195                 return 1;
  196         }
  197         DRM_WAKEUP_INT((void *)&lock_data->lock_queue);
  198         return 0;
  199 }

Cache object: e8661de08dfd51e8ee39c7c67ccb782f

[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.

FreeBSD/Linux Kernel Cross Reference sys/dev/drm/drm_lock.c

FreeBSD/Linux Kernel Cross Reference
sys/dev/drm/drm_lock.c