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drm_irq.c

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/**
 * \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 file_priv DRM file private.
 * \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.
 */
00053 int drm_irq_by_busid(struct drm_device *dev, void *data,
                 struct drm_file *file_priv)
{
      struct drm_irq_busid *p = data;

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

      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);

      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.
 */
00084 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.
 */
00152 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 file_priv DRM file private.
 * \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.
 */
00191 int drm_control(struct drm_device *dev, void *data,
            struct drm_file *file_priv)
{
      struct drm_control *ctl = data;

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


      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 file_priv DRM file private.
 * \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().
 */
00235 int drm_wait_vblank(struct drm_device *dev, void *data, struct drm_file *file_priv)
{
      union drm_wait_vblank *vblwait = data;
      struct timeval now;
      int ret = 0;
      unsigned int flags, seq;

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

      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:
      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().
 */
00356 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().
 */
00399 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.
 */
00438 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);

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