sched: make the scheduler converge to the ideal latency

[linux-2.6/linux-loongson.git] / 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);