1 files changed, 391 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_lock.c b/drivers/gpu/drm/drm_lock.c
new file mode 100644
index 000000000000..0998723cde79
--- /dev/null
+++ b/drivers/gpu/drm/drm_lock.c
@@ -0,0 +1,391 @@
+/**
+ * \file drm_lock.c
+ * 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"
+
+static int drm_notifier(void *priv);
+
+/**
+ * Lock ioctl.
+ *
+ * \param inode device inode.
+ * \param file_priv DRM file private.
+ * \param cmd command.
+ * \param arg user argument, pointing to a drm_lock structure.
+ * \return zero on success or negative number on failure.
+ *
+ * Add the current task to the lock wait queue, and attempt to take to lock.
+ */
+int drm_lock(struct drm_device *dev, void *data, struct drm_file *file_priv)
+{
+        DECLARE_WAITQUEUE(entry, current);
+        struct drm_lock *lock = data;
+        int ret = 0;
+
+        ++file_priv->lock_count;
+
+        if (lock->context == DRM_KERNEL_CONTEXT) {
+                DRM_ERROR("Process %d using kernel context %d\n",
+                          task_pid_nr(current), lock->context);
+                return -EINVAL;
+        }
+
+        DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n",
+                  lock->context, task_pid_nr(current),
+                  dev->lock.hw_lock->lock, lock->flags);
+
+        if (drm_core_check_feature(dev, DRIVER_DMA_QUEUE))
+                if (lock->context < 0)
+                        return -EINVAL;
+
+        add_wait_queue(&dev->lock.lock_queue, &entry);
+        spin_lock_bh(&dev->lock.spinlock);
+        dev->lock.user_waiters++;
+        spin_unlock_bh(&dev->lock.spinlock);
+        for (;;) {
+                __set_current_state(TASK_INTERRUPTIBLE);
+                if (!dev->lock.hw_lock) {
+                        /* Device has been unregistered */
+                        ret = -EINTR;
+                        break;
+                }
+                if (drm_lock_take(&dev->lock, lock->context)) {
+                        dev->lock.file_priv = file_priv;
+                        dev->lock.lock_time = jiffies;
+                        atomic_inc(&dev->counts[_DRM_STAT_LOCKS]);
+                        break;  /* Got lock */
+                }
+
+                /* Contention */
+                schedule();
+                if (signal_pending(current)) {
+                        ret = -ERESTARTSYS;
+                        break;
+                }
+        }
+        spin_lock_bh(&dev->lock.spinlock);
+        dev->lock.user_waiters--;
+        spin_unlock_bh(&dev->lock.spinlock);
+        __set_current_state(TASK_RUNNING);
+        remove_wait_queue(&dev->lock.lock_queue, &entry);
+
+        DRM_DEBUG("%d %s\n", lock->context,
+                  ret ? "interrupted" : "has lock");
+        if (ret) return ret;
+
+        sigemptyset(&dev->sigmask);
+        sigaddset(&dev->sigmask, SIGSTOP);
+        sigaddset(&dev->sigmask, SIGTSTP);
+        sigaddset(&dev->sigmask, SIGTTIN);
+        sigaddset(&dev->sigmask, SIGTTOU);
+        dev->sigdata.context = lock->context;
+        dev->sigdata.lock = dev->lock.hw_lock;
+        block_all_signals(drm_notifier, &dev->sigdata, &dev->sigmask);
+
+        if (dev->driver->dma_ready && (lock->flags & _DRM_LOCK_READY))
+                dev->driver->dma_ready(dev);
+
+        if (dev->driver->dma_quiescent && (lock->flags & _DRM_LOCK_QUIESCENT))
+        {
+                if (dev->driver->dma_quiescent(dev)) {
+                        DRM_DEBUG("%d waiting for DMA quiescent\n",
+                                  lock->context);
+                        return -EBUSY;
+                }
+        }
+
+        if (dev->driver->kernel_context_switch &&
+            dev->last_context != lock->context) {
+                dev->driver->kernel_context_switch(dev, dev->last_context,
+                                                   lock->context);
+        }
+
+        return 0;
+}
+
+/**
+ * Unlock ioctl.
+ *
+ * \param inode device inode.
+ * \param file_priv DRM file private.
+ * \param cmd command.
+ * \param arg user argument, pointing to a drm_lock structure.
+ * \return zero on success or negative number on failure.
+ *
+ * Transfer and free the lock.
+ */
+int drm_unlock(struct drm_device *dev, void *data, struct drm_file *file_priv)
+{
+        struct drm_lock *lock = data;
+        unsigned long irqflags;
+
+        if (lock->context == DRM_KERNEL_CONTEXT) {
+                DRM_ERROR("Process %d using kernel context %d\n",
+                          task_pid_nr(current), lock->context);
+                return -EINVAL;
+        }
+
+        spin_lock_irqsave(&dev->tasklet_lock, irqflags);
+
+        if (dev->locked_tasklet_func) {
+                dev->locked_tasklet_func(dev);
+
+                dev->locked_tasklet_func = NULL;
+        }
+
+        spin_unlock_irqrestore(&dev->tasklet_lock, irqflags);
+
+        atomic_inc(&dev->counts[_DRM_STAT_UNLOCKS]);
+
+        /* kernel_context_switch isn't used by any of the x86 drm
+         * modules but is required by the Sparc driver.
+         */
+        if (dev->driver->kernel_context_switch_unlock)
+                dev->driver->kernel_context_switch_unlock(dev);
+        else {
+                if (drm_lock_free(&dev->lock,lock->context)) {
+                        /* FIXME: Should really bail out here. */
+                }
+        }
+
+        unblock_all_signals();
+        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(struct drm_lock_data *lock_data,
+                  unsigned int context)
+{
+        unsigned int old, new, prev;
+        volatile unsigned int *lock = &lock_data->hw_lock->lock;
+
+        spin_lock_bh(&lock_data->spinlock);
+        do {
+                old = *lock;
+                if (old & _DRM_LOCK_HELD)
+                        new = old | _DRM_LOCK_CONT;
+                else {
+                        new = context | _DRM_LOCK_HELD |
+                                ((lock_data->user_waiters + lock_data->kernel_waiters > 1) ?
+                                 _DRM_LOCK_CONT : 0);
+                }
+                prev = cmpxchg(lock, old, new);
+        } while (prev != old);
+        spin_unlock_bh(&lock_data->spinlock);
+
+        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 ((_DRM_LOCKING_CONTEXT(new)) == context && (new & _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.
+ */
+static int drm_lock_transfer(struct drm_lock_data *lock_data,
+                             unsigned int context)
+{
+        unsigned int old, new, prev;
+        volatile unsigned int *lock = &lock_data->hw_lock->lock;
+
+        lock_data->file_priv = 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(struct drm_lock_data *lock_data, unsigned int context)
+{
+        unsigned int old, new, prev;
+        volatile unsigned int *lock = &lock_data->hw_lock->lock;
+
+        spin_lock_bh(&lock_data->spinlock);
+        if (lock_data->kernel_waiters != 0) {
+                drm_lock_transfer(lock_data, 0);
+                lock_data->idle_has_lock = 1;
+                spin_unlock_bh(&lock_data->spinlock);
+                return 1;
+        }
+        spin_unlock_bh(&lock_data->spinlock);
+
+        do {
+                old = *lock;
+                new = _DRM_LOCKING_CONTEXT(old);
+                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(&lock_data->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.
+ */
+static int drm_notifier(void *priv)
+{
+        struct drm_sigdata *s = (struct drm_sigdata *) 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;
+}
+
+/**
+ * This function returns immediately and takes the hw lock
+ * with the kernel context if it is free, otherwise it gets the highest priority when and if
+ * it is eventually released.
+ *
+ * This guarantees that the kernel will _eventually_ have the lock _unless_ it is held
+ * by a blocked process. (In the latter case an explicit wait for the hardware lock would cause
+ * a deadlock, which is why the "idlelock" was invented).
+ *
+ * This should be sufficient to wait for GPU idle without
+ * having to worry about starvation.
+ */
+
+void drm_idlelock_take(struct drm_lock_data *lock_data)
+{
+        int ret = 0;
+
+        spin_lock_bh(&lock_data->spinlock);
+        lock_data->kernel_waiters++;
+        if (!lock_data->idle_has_lock) {
+
+                spin_unlock_bh(&lock_data->spinlock);
+                ret = drm_lock_take(lock_data, DRM_KERNEL_CONTEXT);
+                spin_lock_bh(&lock_data->spinlock);
+
+                if (ret == 1)
+                        lock_data->idle_has_lock = 1;
+        }
+        spin_unlock_bh(&lock_data->spinlock);
+}
+EXPORT_SYMBOL(drm_idlelock_take);
+
+void drm_idlelock_release(struct drm_lock_data *lock_data)
+{
+        unsigned int old, prev;
+        volatile unsigned int *lock = &lock_data->hw_lock->lock;
+
+        spin_lock_bh(&lock_data->spinlock);
+        if (--lock_data->kernel_waiters == 0) {
+                if (lock_data->idle_has_lock) {
+                        do {
+                                old = *lock;
+                                prev = cmpxchg(lock, old, DRM_KERNEL_CONTEXT);
+                        } while (prev != old);
+                        wake_up_interruptible(&lock_data->lock_queue);
+                        lock_data->idle_has_lock = 0;
+                }
+        }
+        spin_unlock_bh(&lock_data->spinlock);
+}
+EXPORT_SYMBOL(drm_idlelock_release);
+
+
+int drm_i_have_hw_lock(struct drm_device *dev, struct drm_file *file_priv)
+{
+        return (file_priv->lock_count && dev->lock.hw_lock &&
+                _DRM_LOCK_IS_HELD(dev->lock.hw_lock->lock) &&
+                dev->lock.file_priv == file_priv);
+}
+
+EXPORT_SYMBOL(drm_i_have_hw_lock);