drivers/char/drm/drm_irq.c

/**
 * \file drm_irq.c
 * IRQ support
 *
 * \author Rickard E. (Rik) Faith <faith@valinux.com>
 * \author Gareth Hughes <gareth@valinux.com>
 */

/*
 * Created: Fri Mar 19 14:30:16 1999 by faith@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 <linux/interrupt.h>	/* For task queue support */

/**
 * Get interrupt from bus id.
 *
 * \param inode device inode.
 * \param filp file pointer.
 * \param cmd command.
 * \param arg user argument, pointing to a drm_irq_busid structure.
 * \return zero on success or a negative number on failure.
 *
 * Finds the PCI device with the specified bus id and gets its IRQ number.
 * This IOCTL is deprecated, and will now return EINVAL for any busid not equal
 * to that of the device that this DRM instance attached to.
 */
int drm_irq_by_busid(struct inode *inode, struct file *filp,
		     unsigned int cmd, unsigned long arg)
{
	struct drm_file *priv = filp->private_data;
	struct drm_device *dev = priv->head->dev;
	struct drm_irq_busid __user *argp = (void __user *)arg;
	struct drm_irq_busid p;

	if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
		return -EINVAL;

	if (copy_from_user(&p, argp, sizeof(p)))
		return -EFAULT;

	if ((p.busnum >> 8) != drm_get_pci_domain(dev) ||
	    (p.busnum & 0xff) != dev->pdev->bus->number ||
	    p.devnum != PCI_SLOT(dev->pdev->devfn) || p.funcnum != PCI_FUNC(dev->pdev->devfn))
		return -EINVAL;

	p.irq = dev->irq;

	DRM_DEBUG("%d:%d:%d => IRQ %d\n", p.busnum, p.devnum, p.funcnum, p.irq);
	if (copy_to_user(argp, &p, sizeof(p)))
		return -EFAULT;
	return 0;
}

/**
 * Install IRQ handler.
 *
 * \param dev DRM device.
 * \param irq IRQ number.
 *
 * Initializes the IRQ related data, and setups drm_device::vbl_queue. Installs the handler, calling the driver
 * \c drm_driver_irq_preinstall() and \c drm_driver_irq_postinstall() functions
 * before and after the installation.
 */
static int drm_irq_install(struct drm_device * dev)
{
	int ret;
	unsigned long sh_flags = 0;

	if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
		return -EINVAL;

	if (dev->irq == 0)
		return -EINVAL;

	mutex_lock(&dev->struct_mutex);

	/* Driver must have been initialized */
	if (!dev->dev_private) {
		mutex_unlock(&dev->struct_mutex);
		return -EINVAL;
	}

	if (dev->irq_enabled) {
		mutex_unlock(&dev->struct_mutex);
		return -EBUSY;
	}
	dev->irq_enabled = 1;
	mutex_unlock(&dev->struct_mutex);

	DRM_DEBUG("%s: irq=%d\n", __FUNCTION__, dev->irq);

	if (drm_core_check_feature(dev, DRIVER_IRQ_VBL)) {
		init_waitqueue_head(&dev->vbl_queue);

		spin_lock_init(&dev->vbl_lock);

		INIT_LIST_HEAD(&dev->vbl_sigs);
		INIT_LIST_HEAD(&dev->vbl_sigs2);

		dev->vbl_pending = 0;
	}

	/* Before installing handler */
	dev->driver->irq_preinstall(dev);

	/* Install handler */
	if (drm_core_check_feature(dev, DRIVER_IRQ_SHARED))
		sh_flags = IRQF_SHARED;

	ret = request_irq(dev->irq, dev->driver->irq_handler,
			  sh_flags, dev->devname, dev);
	if (ret < 0) {
		mutex_lock(&dev->struct_mutex);
		dev->irq_enabled = 0;
		mutex_unlock(&dev->struct_mutex);
		return ret;
	}

	/* After installing handler */
	dev->driver->irq_postinstall(dev);

	return 0;
}

/**
 * Uninstall the IRQ handler.
 *
 * \param dev DRM device.
 *
 * Calls the driver's \c drm_driver_irq_uninstall() function, and stops the irq.
 */
int drm_irq_uninstall(struct drm_device * dev)
{
	int irq_enabled;

	if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
		return -EINVAL;

	mutex_lock(&dev->struct_mutex);
	irq_enabled = dev->irq_enabled;
	dev->irq_enabled = 0;
	mutex_unlock(&dev->struct_mutex);

	if (!irq_enabled)
		return -EINVAL;

	DRM_DEBUG("%s: irq=%d\n", __FUNCTION__, dev->irq);

	dev->driver->irq_uninstall(dev);

	free_irq(dev->irq, dev);

	dev->locked_tasklet_func = NULL;

	return 0;
}

EXPORT_SYMBOL(drm_irq_uninstall);

/**
 * IRQ control ioctl.
 *
 * \param inode device inode.
 * \param filp file pointer.
 * \param cmd command.
 * \param arg user argument, pointing to a drm_control structure.
 * \return zero on success or a negative number on failure.
 *
 * Calls irq_install() or irq_uninstall() according to \p arg.
 */
int drm_control(struct inode *inode, struct file *filp,
		unsigned int cmd, unsigned long arg)
{
	struct drm_file *priv = filp->private_data;
	struct drm_device *dev = priv->head->dev;
	struct drm_control ctl;

	/* if we haven't irq we fallback for compatibility reasons - this used to be a separate function in drm_dma.h */

	if (copy_from_user(&ctl, (struct drm_control __user *) arg, sizeof(ctl)))
		return -EFAULT;

	switch (ctl.func) {
	case DRM_INST_HANDLER:
		if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
			return 0;
		if (dev->if_version < DRM_IF_VERSION(1, 2) &&
		    ctl.irq != dev->irq)
			return -EINVAL;
		return drm_irq_install(dev);
	case DRM_UNINST_HANDLER:
		if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
			return 0;
		return drm_irq_uninstall(dev);
	default:
		return -EINVAL;
	}
}

/**
 * Wait for VBLANK.
 *
 * \param inode device inode.
 * \param filp file pointer.
 * \param cmd command.
 * \param data user argument, pointing to a drm_wait_vblank structure.
 * \return zero on success or a negative number on failure.
 *
 * Verifies the IRQ is installed.
 *
 * If a signal is requested checks if this task has already scheduled the same signal
 * for the same vblank sequence number - nothing to be done in
 * that case. If the number of tasks waiting for the interrupt exceeds 100 the
 * function fails. Otherwise adds a new entry to drm_device::vbl_sigs for this
 * task.
 *
 * If a signal is not requested, then calls vblank_wait().
 */
int drm_wait_vblank(DRM_IOCTL_ARGS)
{
	struct drm_file *priv = filp->private_data;
	struct drm_device *dev = priv->head->dev;
	union drm_wait_vblank __user *argp = (void __user *)data;
	union drm_wait_vblank vblwait;
	struct timeval now;
	int ret = 0;
	unsigned int flags, seq;

	if (!dev->irq)
		return -EINVAL;

	if (copy_from_user(&vblwait, argp, sizeof(vblwait)))
		return -EFAULT;

	if (vblwait.request.type &
	    ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK)) {
		DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
			  vblwait.request.type,
			  (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK));
		return -EINVAL;
	}

	flags = vblwait.request.type & _DRM_VBLANK_FLAGS_MASK;

	if (!drm_core_check_feature(dev, (flags & _DRM_VBLANK_SECONDARY) ?
				    DRIVER_IRQ_VBL2 : DRIVER_IRQ_VBL))
		return -EINVAL;

	seq = atomic_read((flags & _DRM_VBLANK_SECONDARY) ? &dev->vbl_received2
			  : &dev->vbl_received);

	switch (vblwait.request.type & _DRM_VBLANK_TYPES_MASK) {
	case _DRM_VBLANK_RELATIVE:
		vblwait.request.sequence += seq;
		vblwait.request.type &= ~_DRM_VBLANK_RELATIVE;
	case _DRM_VBLANK_ABSOLUTE:
		break;
	default:
		return -EINVAL;
	}

	if ((flags & _DRM_VBLANK_NEXTONMISS) &&
	    (seq - vblwait.request.sequence) <= (1<<23)) {
		vblwait.request.sequence = seq + 1;
	}

	if (flags & _DRM_VBLANK_SIGNAL) {
		unsigned long irqflags;
		struct list_head *vbl_sigs = (flags & _DRM_VBLANK_SECONDARY)
				      ? &dev->vbl_sigs2 : &dev->vbl_sigs;
		struct drm_vbl_sig *vbl_sig;

		spin_lock_irqsave(&dev->vbl_lock, irqflags);

		/* Check if this task has already scheduled the same signal
		 * for the same vblank sequence number; nothing to be done in
		 * that case
		 */
		list_for_each_entry(vbl_sig, vbl_sigs, head) {
			if (vbl_sig->sequence == vblwait.request.sequence
			    && vbl_sig->info.si_signo == vblwait.request.signal
			    && vbl_sig->task == current) {
				spin_unlock_irqrestore(&dev->vbl_lock,
						       irqflags);
				vblwait.reply.sequence = seq;
				goto done;
			}
		}

		if (dev->vbl_pending >= 100) {
			spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
			return -EBUSY;
		}

		dev->vbl_pending++;

		spin_unlock_irqrestore(&dev->vbl_lock, irqflags);

		if (!
		    (vbl_sig =
		     drm_alloc(sizeof(struct drm_vbl_sig), DRM_MEM_DRIVER))) {
			return -ENOMEM;
		}

		memset((void *)vbl_sig, 0, sizeof(*vbl_sig));

		vbl_sig->sequence = vblwait.request.sequence;
		vbl_sig->info.si_signo = vblwait.request.signal;
		vbl_sig->task = current;

		spin_lock_irqsave(&dev->vbl_lock, irqflags);

		list_add_tail(&vbl_sig->head, vbl_sigs);

		spin_unlock_irqrestore(&dev->vbl_lock, irqflags);

		vblwait.reply.sequence = seq;
	} else {
		if (flags & _DRM_VBLANK_SECONDARY) {
			if (dev->driver->vblank_wait2)
				ret = dev->driver->vblank_wait2(dev, &vblwait.request.sequence);
		} else if (dev->driver->vblank_wait)
			ret =
			    dev->driver->vblank_wait(dev,
						     &vblwait.request.sequence);

		do_gettimeofday(&now);
		vblwait.reply.tval_sec = now.tv_sec;
		vblwait.reply.tval_usec = now.tv_usec;
	}

      done:
	if (copy_to_user(argp, &vblwait, sizeof(vblwait)))
		return -EFAULT;

	return ret;
}

/**
 * Send the VBLANK signals.
 *
 * \param dev DRM device.
 *
 * Sends a signal for each task in drm_device::vbl_sigs and empties the list.
 *
 * If a signal is not requested, then calls vblank_wait().
 */
void drm_vbl_send_signals(struct drm_device * dev)
{
	unsigned long flags;
	int i;

	spin_lock_irqsave(&dev->vbl_lock, flags);

	for (i = 0; i < 2; i++) {
		struct drm_vbl_sig *vbl_sig, *tmp;
		struct list_head *vbl_sigs = i ? &dev->vbl_sigs2 : &dev->vbl_sigs;
		unsigned int vbl_seq = atomic_read(i ? &dev->vbl_received2 :
						   &dev->vbl_received);

		list_for_each_entry_safe(vbl_sig, tmp, vbl_sigs, head) {
			if ((vbl_seq - vbl_sig->sequence) <= (1 << 23)) {
				vbl_sig->info.si_code = vbl_seq;
				send_sig_info(vbl_sig->info.si_signo,
					      &vbl_sig->info, vbl_sig->task);

				list_del(&vbl_sig->head);

				drm_free(vbl_sig, sizeof(*vbl_sig),
					 DRM_MEM_DRIVER);

				dev->vbl_pending--;
			}
		}
	}

	spin_unlock_irqrestore(&dev->vbl_lock, flags);
}

EXPORT_SYMBOL(drm_vbl_send_signals);

/**
 * Tasklet wrapper function.
 *
 * \param data DRM device in disguise.
 *
 * Attempts to grab the HW lock and calls the driver callback on success. On
 * failure, leave the lock marked as contended so the callback can be called
 * from drm_unlock().
 */
static void drm_locked_tasklet_func(unsigned long data)
{
	struct drm_device *dev = (struct drm_device *)data;
	unsigned long irqflags;

	spin_lock_irqsave(&dev->tasklet_lock, irqflags);

	if (!dev->locked_tasklet_func ||
	    !drm_lock_take(&dev->lock,
			   DRM_KERNEL_CONTEXT)) {
		spin_unlock_irqrestore(&dev->tasklet_lock, irqflags);
		return;
	}

	dev->lock.lock_time = jiffies;
	atomic_inc(&dev->counts[_DRM_STAT_LOCKS]);

	dev->locked_tasklet_func(dev);

	drm_lock_free(&dev->lock,
		      DRM_KERNEL_CONTEXT);

	dev->locked_tasklet_func = NULL;

	spin_unlock_irqrestore(&dev->tasklet_lock, irqflags);
}

/**
 * Schedule a tasklet to call back a driver hook with the HW lock held.
 *
 * \param dev DRM device.
 * \param func Driver callback.
 *
 * This is intended for triggering actions that require the HW lock from an
 * interrupt handler. The lock will be grabbed ASAP after the interrupt handler
 * completes. Note that the callback may be called from interrupt or process
 * context, it must not make any assumptions about this. Also, the HW lock will
 * be held with the kernel context or any client context.
 */
void drm_locked_tasklet(struct drm_device *dev, void (*func)(struct drm_device *))
{
	unsigned long irqflags;
	static DECLARE_TASKLET(drm_tasklet, drm_locked_tasklet_func, 0);

	if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ) ||
	    test_bit(TASKLET_STATE_SCHED, &drm_tasklet.state))
		return;

	spin_lock_irqsave(&dev->tasklet_lock, irqflags);

	if (dev->locked_tasklet_func) {
		spin_unlock_irqrestore(&dev->tasklet_lock, irqflags);
		return;
	}

	dev->locked_tasklet_func = func;

	spin_unlock_irqrestore(&dev->tasklet_lock, irqflags);

	drm_tasklet.data = (unsigned long)dev;

	tasklet_hi_schedule(&drm_tasklet);
}
EXPORT_SYMBOL(drm_locked_tasklet);