gamma_dma.c

内核linux2.4.20,可跟rtlinux3.2打补丁 组成实时linux系统,编译内核

			continue;
		}
		buf = dma->buflist[ idx ];
		if (buf->pid != current->pid) {
			DRM_ERROR("Process %d using buffer owned by %d\n",
				  current->pid, buf->pid);
			retcode = -EINVAL;
			goto cleanup;
		}
		if (buf->list != DRM_LIST_NONE) {
			DRM_ERROR("Process %d using %d's buffer on list %d\n",
				  current->pid, buf->pid, buf->list);
			retcode = -EINVAL;
			goto cleanup;
		}
				/* This isn't a race condition on
				   buf->list, since our concern is the
				   buffer reclaim during the time the
				   process closes the /dev/drm? handle, so
				   it can't also be doing DMA. */
		buf->list	  = DRM_LIST_PRIO;
		buf->used	  = d->send_sizes[i];
		buf->context	  = d->context;
		buf->while_locked = d->flags & _DRM_DMA_WHILE_LOCKED;
		address		  = (unsigned long)buf->address;
		length		  = buf->used;
		if (!length) {
			DRM_ERROR("0 length buffer\n");
		}
		if (buf->pending) {
			DRM_ERROR("Sending pending buffer:"
				  " buffer %d, offset %d\n",
				  d->send_indices[i], i);
			retcode = -EINVAL;
			goto cleanup;
		}
		if (buf->waiting) {
			DRM_ERROR("Sending waiting buffer:"
				  " buffer %d, offset %d\n",
				  d->send_indices[i], i);
			retcode = -EINVAL;
			goto cleanup;
		}
		buf->pending = 1;
		
		if (dev->last_context != buf->context
		    && !(dev->queuelist[buf->context]->flags
			 & _DRM_CONTEXT_PRESERVED)) {
			add_wait_queue(&dev->context_wait, &entry);
			current->state = TASK_INTERRUPTIBLE;
				/* PRE: dev->last_context != buf->context */
			drm_context_switch(dev, dev->last_context,
					   buf->context);
				/* POST: we will wait for the context
				   switch and will dispatch on a later call
				   when dev->last_context == buf->context.
				   NOTE WE HOLD THE LOCK THROUGHOUT THIS
				   TIME! */
			schedule();
			current->state = TASK_RUNNING;
			remove_wait_queue(&dev->context_wait, &entry);
			if (signal_pending(current)) {
				retcode = -EINTR;
				goto cleanup;
			}
			if (dev->last_context != buf->context) {
				DRM_ERROR("Context mismatch: %d %d\n",
					  dev->last_context,
					  buf->context);
			}
		}

#if DRM_DMA_HISTOGRAM
		buf->time_queued     = get_cycles();
		buf->time_dispatched = buf->time_queued;
#endif
		gamma_dma_dispatch(dev, address, length);
		atomic_add(length, &dma->total_bytes);
		atomic_inc(&dma->total_dmas);
		
		if (last_buf) {
			drm_free_buffer(dev, last_buf);
		}
		last_buf = buf;
	}


cleanup:
	if (last_buf) {
		gamma_dma_ready(dev);
		drm_free_buffer(dev, last_buf);
	}
	
	if (must_free && !dev->context_flag) {
		if (drm_lock_free(dev, &dev->lock.hw_lock->lock,
				  DRM_KERNEL_CONTEXT)) {
			DRM_ERROR("\n");
		}
	}
	clear_bit(0, &dev->interrupt_flag);
	return retcode;
}

static int gamma_dma_send_buffers(drm_device_t *dev, drm_dma_t *d)
{
	DECLARE_WAITQUEUE(entry, current);
	drm_buf_t	  *last_buf = NULL;
	int		  retcode   = 0;
	drm_device_dma_t  *dma	    = dev->dma;

	if (d->flags & _DRM_DMA_BLOCK) {
		last_buf = dma->buflist[d->send_indices[d->send_count-1]];
		add_wait_queue(&last_buf->dma_wait, &entry);
	}
	
	if ((retcode = drm_dma_enqueue(dev, d))) {
		if (d->flags & _DRM_DMA_BLOCK)
			remove_wait_queue(&last_buf->dma_wait, &entry);
		return retcode;
	}
	
	gamma_dma_schedule(dev, 0);
	
	if (d->flags & _DRM_DMA_BLOCK) {
		DRM_DEBUG("%d waiting\n", current->pid);
		for (;;) {
			current->state = TASK_INTERRUPTIBLE;
			if (!last_buf->waiting && !last_buf->pending)
				break; /* finished */
			schedule();
			if (signal_pending(current)) {
				retcode = -EINTR; /* Can't restart */
				break;
			}
		}
		current->state = TASK_RUNNING;
		DRM_DEBUG("%d running\n", current->pid);
		remove_wait_queue(&last_buf->dma_wait, &entry);
		if (!retcode
		    || (last_buf->list==DRM_LIST_PEND && !last_buf->pending)) {
			if (!waitqueue_active(&last_buf->dma_wait)) {
				drm_free_buffer(dev, last_buf);
			}
		}
		if (retcode) {
			DRM_ERROR("ctx%d w%d p%d c%d i%d l%d %d/%d\n",
				  d->context,
				  last_buf->waiting,
				  last_buf->pending,
				  DRM_WAITCOUNT(dev, d->context),
				  last_buf->idx,
				  last_buf->list,
				  last_buf->pid,
				  current->pid);
		}
	}
	return retcode;
}

int gamma_dma(struct inode *inode, struct file *filp, unsigned int cmd,
	      unsigned long arg)
{
	drm_file_t	  *priv	    = filp->private_data;
	drm_device_t	  *dev	    = priv->dev;
	drm_device_dma_t  *dma	    = dev->dma;
	int		  retcode   = 0;
	drm_dma_t	  d;

	if (copy_from_user(&d, (drm_dma_t *)arg, sizeof(d)))
		return -EFAULT;
	DRM_DEBUG("%d %d: %d send, %d req\n",
		  current->pid, d.context, d.send_count, d.request_count);

	if (d.context == DRM_KERNEL_CONTEXT || d.context >= dev->queue_slots) {
		DRM_ERROR("Process %d using context %d\n",
			  current->pid, d.context);
		return -EINVAL;
	}
	if (d.send_count < 0 || d.send_count > dma->buf_count) {
		DRM_ERROR("Process %d trying to send %d buffers (of %d max)\n",
			  current->pid, d.send_count, dma->buf_count);
		return -EINVAL;
	}
	if (d.request_count < 0 || d.request_count > dma->buf_count) {
		DRM_ERROR("Process %d trying to get %d buffers (of %d max)\n",
			  current->pid, d.request_count, dma->buf_count);
		return -EINVAL;
	}

	if (d.send_count) {
		if (d.flags & _DRM_DMA_PRIORITY)
			retcode = gamma_dma_priority(dev, &d);
		else 
			retcode = gamma_dma_send_buffers(dev, &d);
	}

	d.granted_count = 0;

	if (!retcode && d.request_count) {
		retcode = drm_dma_get_buffers(dev, &d);
	}

	DRM_DEBUG("%d returning, granted = %d\n",
		  current->pid, d.granted_count);
	if (copy_to_user((drm_dma_t *)arg, &d, sizeof(d)))
		return -EFAULT;

	return retcode;
}

int gamma_irq_install(drm_device_t *dev, int irq)
{
	int retcode;

	if (!irq)     return -EINVAL;
	
	down(&dev->struct_sem);
	if (dev->irq) {
		up(&dev->struct_sem);
		return -EBUSY;
	}
	dev->irq = irq;
	up(&dev->struct_sem);
	
	DRM_DEBUG("%d\n", irq);

	dev->context_flag     = 0;
	dev->interrupt_flag   = 0;
	dev->dma_flag	      = 0;
	
	dev->dma->next_buffer = NULL;
	dev->dma->next_queue  = NULL;
	dev->dma->this_buffer = NULL;

	INIT_LIST_HEAD(&dev->tq.list);
	dev->tq.sync	      = 0;
	dev->tq.routine	      = gamma_dma_schedule_tq_wrapper;
	dev->tq.data	      = dev;


				/* Before installing handler */
	GAMMA_WRITE(GAMMA_GCOMMANDMODE, 0);
	GAMMA_WRITE(GAMMA_GDMACONTROL, 0);
	
				/* Install handler */
	if ((retcode = request_irq(dev->irq,
				   gamma_dma_service,
				   0,
				   dev->devname,
				   dev))) {
		down(&dev->struct_sem);
		dev->irq = 0;
		up(&dev->struct_sem);
		return retcode;
	}

				/* After installing handler */
	GAMMA_WRITE(GAMMA_GINTENABLE,	    0x2001);
	GAMMA_WRITE(GAMMA_COMMANDINTENABLE, 0x0008);
	GAMMA_WRITE(GAMMA_GDELAYTIMER,	   0x39090);
	
	return 0;
}

int gamma_irq_uninstall(drm_device_t *dev)
{
	int irq;

	down(&dev->struct_sem);
	irq	 = dev->irq;
	dev->irq = 0;
	up(&dev->struct_sem);
	
	if (!irq) return -EINVAL;
	
	DRM_DEBUG("%d\n", irq);
	
	GAMMA_WRITE(GAMMA_GDELAYTIMER,	    0);
	GAMMA_WRITE(GAMMA_COMMANDINTENABLE, 0);
	GAMMA_WRITE(GAMMA_GINTENABLE,	    0);
	free_irq(irq, dev);

	return 0;
}


int gamma_control(struct inode *inode, struct file *filp, unsigned int cmd,
		  unsigned long arg)
{
	drm_file_t	*priv	= filp->private_data;
	drm_device_t	*dev	= priv->dev;
	drm_control_t	ctl;
	int		retcode;
	
	if (copy_from_user(&ctl, (drm_control_t *)arg, sizeof(ctl)))
		return -EFAULT;
	
	switch (ctl.func) {
	case DRM_INST_HANDLER:
		if ((retcode = gamma_irq_install(dev, ctl.irq)))
			return retcode;
		break;
	case DRM_UNINST_HANDLER:
		if ((retcode = gamma_irq_uninstall(dev)))
			return retcode;
		break;
	default:
		return -EINVAL;
	}
	return 0;
}

int gamma_lock(struct inode *inode, struct file *filp, unsigned int cmd,
	       unsigned long arg)
{
	drm_file_t	  *priv	  = filp->private_data;
	drm_device_t	  *dev	  = priv->dev;
	DECLARE_WAITQUEUE(entry, current);
	int		  ret	= 0;
	drm_lock_t	  lock;
	drm_queue_t	  *q;
#if DRM_DMA_HISTOGRAM
	cycles_t	  start;

	dev->lck_start = start = get_cycles();
#endif

	if (copy_from_user(&lock, (drm_lock_t *)arg, sizeof(lock)))
		return -EFAULT;

	if (lock.context == DRM_KERNEL_CONTEXT) {
		DRM_ERROR("Process %d using kernel context %d\n",
			  current->pid, lock.context);
		return -EINVAL;
	}

	DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n",
		  lock.context, current->pid, dev->lock.hw_lock->lock,
		  lock.flags);

	if (lock.context < 0 || lock.context >= dev->queue_count)
		return -EINVAL;
	q = dev->queuelist[lock.context];
	
	ret = drm_flush_block_and_flush(dev, lock.context, lock.flags);

	if (!ret) {
		if (_DRM_LOCKING_CONTEXT(dev->lock.hw_lock->lock)
		    != lock.context) {
			long j = jiffies - dev->lock.lock_time;

			if (j > 0 && j <= DRM_LOCK_SLICE) {
				/* Can't take lock if we just had it and
				   there is contention. */
				current->state = TASK_INTERRUPTIBLE;
				schedule_timeout(j);
			}
		}
		add_wait_queue(&dev->lock.lock_queue, &entry);
		for (;;) {
			current->state = TASK_INTERRUPTIBLE;
			if (!dev->lock.hw_lock) {
				/* Device has been unregistered */
				ret = -EINTR;
				break;
			}
			if (drm_lock_take(&dev->lock.hw_lock->lock,
					  lock.context)) {
				dev->lock.pid	    = current->pid;
				dev->lock.lock_time = jiffies;
				atomic_inc(&dev->total_locks);
				atomic_inc(&q->total_locks);
				break;	/* Got lock */
			}
			
				/* Contention */
			atomic_inc(&dev->total_sleeps);
			schedule();
			if (signal_pending(current)) {
				ret = -ERESTARTSYS;
				break;
			}
		}
		current->state = TASK_RUNNING;
		remove_wait_queue(&dev->lock.lock_queue, &entry);
	}

	drm_flush_unblock(dev, lock.context, lock.flags); /* cleanup phase */
	
	if (!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 (lock.flags & _DRM_LOCK_READY)
			gamma_dma_ready(dev);
		if (lock.flags & _DRM_LOCK_QUIESCENT) {
			if (gamma_found() == 1) {
				gamma_dma_quiescent_single(dev);
			} else {
				gamma_dma_quiescent_dual(dev);
			}
		}
	}
	DRM_DEBUG("%d %s\n", lock.context, ret ? "interrupted" : "has lock");

#if DRM_DMA_HISTOGRAM
	atomic_inc(&dev->histo.lacq[drm_histogram_slot(get_cycles() - start)]);
#endif
	
	return ret;
}