renesas/drm.git - libdrm, cloned from git://anongit.freedesktop.org/mesa/drm

Age	Commit message (Expand)	Author
2007-06-28	nouveau/nv50: skeletal backend	Ben Skeggs

/** * \file drm_lock.h * IOCTLs for locking * * \author Rickard E. (Rik) Faith <faith@valinux.com> * \author Gareth Hughes <gareth@valinux.com> */ /* * Created: Tue Feb 2 08:37:54 1999 by faith@valinux.com * * Copyright 1999 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" /** No-op ioctl. */ int DRM(noop)(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg) { DRM_DEBUG("\n"); return 0; } /** * Take the heavyweight lock. * * \param lock lock pointer. * \param context locking context. * \return one if the lock is held, or zero otherwise. * * Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction. */ int DRM(lock_take)(__volatile__ unsigned int *lock, unsigned int context) { unsigned int old, new, prev; do { old = *lock; if (old & _DRM_LOCK_HELD) new = old | _DRM_LOCK_CONT; else new = context | _DRM_LOCK_HELD; prev = cmpxchg(lock, old, new); } while (prev != old); if (_DRM_LOCKING_CONTEXT(old) == context) { if (old & _DRM_LOCK_HELD) { if (context != DRM_KERNEL_CONTEXT) { DRM_ERROR("%d holds heavyweight lock\n", context); } return 0; } } if (new == (context | _DRM_LOCK_HELD)) { /* Have lock */ return 1; } return 0; } /** * This takes a lock forcibly and hands it to context. Should ONLY be used * inside *_unlock to give lock to kernel before calling *_dma_schedule. * * \param dev DRM device. * \param lock lock pointer. * \param context locking context. * \return always one. * * Resets the lock file pointer. * Marks the lock as held by the given context, via the \p cmpxchg instruction. */ int DRM(lock_transfer)(drm_device_t *dev, __volatile__ unsigned int *lock, unsigned int context) { unsigned int old, new, prev; dev->lock.filp = NULL; do { old = *lock; new = context | _DRM_LOCK_HELD; prev = cmpxchg(lock, old, new); } while (prev != old); return 1; } /** * Free lock. * * \param dev DRM device. * \param lock lock. * \param context context. * * Resets the lock file pointer. * Marks the lock as not held, via the \p cmpxchg instruction. Wakes any task * waiting on the lock queue. */ int DRM(lock_free)(drm_device_t *dev, __volatile__ unsigned int *lock, unsigned int context) { unsigned int old, new, prev; dev->lock.filp = NULL; do { old = *lock; new = 0; prev = cmpxchg(lock, old, new); } while (prev != old); if (_DRM_LOCK_IS_HELD(old) && _DRM_LOCKING_CONTEXT(old) != context) { DRM_ERROR("%d freed heavyweight lock held by %d\n", context, _DRM_LOCKING_CONTEXT(old)); return 1; } wake_up_interruptible(&dev->lock.lock_queue); return 0; } /** * If we get here, it means that the process has called DRM_IOCTL_LOCK * without calling DRM_IOCTL_UNLOCK. * * If the lock is not held, then let the signal proceed as usual. If the lock * is held, then set the contended flag and keep the signal blocked. * * \param priv pointer to a drm_sigdata structure. * \return one if the signal should be delivered normally, or zero if the * signal should be blocked. */ int DRM(notifier)(void *priv) { drm_sigdata_t *s = (drm_sigdata_t *)priv; unsigned int old, new, prev; /* Allow signal delivery if lock isn't held */ if (!s->lock || !_DRM_LOCK_IS_HELD(s->lock->lock) || _DRM_LOCKING_CONTEXT(s->lock->lock) != s->context) return 1; /* Otherwise, set flag to force call to drmUnlock */ do { old = s->lock->lock; new = old | _DRM_LOCK_CONT; prev = cmpxchg(&s->lock->lock, old, new); } while (prev != old); return 0; }