/**
 * \file drm_fops.c
 * File operations for DRM
 *
 * \author Rickard E. (Rik) Faith <faith@valinux.com>
 * \author Daryll Strauss <daryll@valinux.com>
 * \author Gareth Hughes <gareth@valinux.com>
 */

/*
 * Created: Mon Jan  4 08:58:31 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"
#include "drm_sarea.h"
#include <linux/poll.h>

static int drm_open_helper(struct inode *inode, struct file *filp,
                           struct drm_device * dev);

static int drm_setup(struct drm_device * dev)
{
        drm_local_map_t *map;
        int i;
        int ret;
        u32 sareapage;

        if (dev->driver->firstopen) {
                ret = dev->driver->firstopen(dev);
                if (ret != 0)
                        return ret;
        }

        dev->magicfree.next = NULL;

        /* prebuild the SAREA */
        sareapage = max_t(unsigned, SAREA_MAX, PAGE_SIZE);
        i = drm_addmap(dev, 0, sareapage, _DRM_SHM, _DRM_CONTAINS_LOCK, &map);
        if (i != 0)
                return i;

        atomic_set(&dev->ioctl_count, 0);
        atomic_set(&dev->vma_count, 0);
        dev->buf_use = 0;
        atomic_set(&dev->buf_alloc, 0);

        if (drm_core_check_feature(dev, DRIVER_HAVE_DMA)) {
                i = drm_dma_setup(dev);
                if (i < 0)
                        return i;
        }

        for (i = 0; i < ARRAY_SIZE(dev->counts); i++)
                atomic_set(&dev->counts[i], 0);

        drm_ht_create(&dev->magiclist, DRM_MAGIC_HASH_ORDER);
        INIT_LIST_HEAD(&dev->magicfree);

        dev->sigdata.lock = NULL;
        init_waitqueue_head(&dev->lock.lock_queue);
        dev->queue_count = 0;
        dev->queue_reserved = 0;
        dev->queue_slots = 0;
        dev->queuelist = NULL;
        dev->irq_enabled = 0;
        dev->context_flag = 0;
        dev->interrupt_flag = 0;
        dev->dma_flag = 0;
        dev->last_context = 0;
        dev->last_switch = 0;
        dev->last_checked = 0;
        init_waitqueue_head(&dev->context_wait);
        dev->if_version = 0;

        dev->ctx_start = 0;
        dev->lck_start = 0;

        dev->buf_async = NULL;
        init_waitqueue_head(&dev->buf_readers);
        init_waitqueue_head(&dev->buf_writers);

        DRM_DEBUG("\n");

        /*
         * The kernel's context could be created here, but is now created
         * in drm_dma_enqueue.  This is more resource-efficient for
         * hardware that does not do DMA, but may mean that
         * drm_select_queue fails between the time the interrupt is
         * initialized and the time the queues are initialized.
         */

        return 0;
}

/**
 * Open file.
 *
 * \param inode device inode
 * \param filp file pointer.
 * \return zero on success or a negative number on failure.
 *
 * Searches the DRM device with the same minor number, calls open_helper(), and
 * increments the device open count. If the open count was previous at zero,
 * i.e., it's the first that the device is open, then calls setup().
 */
int drm_open(struct inode *inode, struct file *filp)
{
        struct drm_device *dev = NULL;
        int minor = iminor(inode);
        int retcode = 0;

        if (!((minor >= 0) && (minor < drm_cards_limit)))
                return -ENODEV;

        if (!drm_heads[minor])
                return -ENODEV;

        if (!(dev = drm_heads[minor]->dev))
                return -ENODEV;

        retcode = drm_open_helper(inode, filp, dev);
        if (!retcode) {
                atomic_inc(&dev->counts[_DRM_STAT_OPENS]);
                spin_lock(&dev->count_lock);
                if (!dev->open_count++) {
                        spin_unlock(&dev->count_lock);
                        return drm_setup(dev);
                }
                spin_unlock(&dev->count_lock);
        }

        return retcode;
}
EXPORT_SYMBOL(drm_open);

/**
 * File \c open operation.
 *
 * \param inode device inode.
 * \param filp file pointer.
 *
 * Puts the dev->fops corresponding to the device minor number into
 * \p filp, call the \c open method, and restore the file operations.
 */
int drm_stub_open(struct inode *inode, struct file *filp)
{
        struct drm_device *dev = NULL;
        int minor = iminor(inode);
        int err = -ENODEV;
        const struct file_operations *old_fops;

        DRM_DEBUG("\n");

        if (!((minor >= 0) && (minor < drm_cards_limit)))
                return -ENODEV;

        if (!drm_heads[minor])
                return -ENODEV;

        if (!(dev = drm_heads[minor]->dev))
                return -ENODEV;

        old_fops = filp->f_op;
        filp->f_op = fops_get(&dev->driver->fops);
        if (filp->f_op->open && (err = filp->f_op->open(inode, filp))) {
                fops_put(filp->f_op);
                filp->f_op = fops_get(old_fops);
        }
        fops_put(old_fops);

        return err;
}

/**
 * Check whether DRI will run on this CPU.
 *
 * \return non-zero if the DRI will run on this CPU, or zero otherwise.
 */
static int drm_cpu_valid(void)
{
#if defined(__i386__)
        if (boot_cpu_data.x86 == 3)
                return 0;       /* No cmpxchg on a 386 */
#endif
#if defined(__sparc__) && !defined(__sparc_v9__)
        return 0;               /* No cmpxchg before v9 sparc. */
#endif
        return 1;
}

/**
 * Called whenever a process opens /dev/drm.
 *
 * \param inode device inode.
 * \param filp file pointer.
 * \param dev device.
 * \return zero on success or a negative number on failure.
 *
 * Creates and initializes a drm_file structure for the file private data in \p
 * filp and add it into the double linked list in \p dev.
 */
static int drm_open_helper(struct inode *inode, struct file *filp,
                           struct drm_device * dev)
{
        int minor = iminor(inode);
        struct drm_file *priv;
        int ret;

        if (filp->f_flags & O_EXCL)
                return -EBUSY;  /* No exclusive opens */
        if (!drm_cpu_valid())
                return -EINVAL;

        DRM_DEBUG("pid = %d, minor = %d\n", task_pid_nr(current), minor);

        priv = drm_alloc(sizeof(*priv), DRM_MEM_FILES);
        if (!priv)
                return -ENOMEM;

        memset(priv, 0, sizeof(*priv));
        filp->private_data = priv;
        priv->filp = filp;
        priv->uid = current->euid;
        priv->pid = task_pid_nr(current);
        priv->minor = minor;
        priv->head = drm_heads[minor];
        priv->ioctl_count = 0;
        /* for compatibility root is always authenticated */
        priv->authenticated = capable(CAP_SYS_ADMIN);
        priv->lock_count = 0;

        INIT_LIST_HEAD(&priv->lhead);

        if (dev->driver->open) {
                ret = dev->driver->open(dev, priv);
                if (ret < 0)
                        goto out_free;
        }

        mutex_lock(&dev->struct_mutex);
        if (list_empty(&dev->filelist))
                priv->master = 1;

        list_add(&priv->lhead, &dev->filelist);
        mutex_unlock(&dev->struct_mutex);

#ifdef __alpha__
        /*
         * Default the hose
         */
        if (!dev->hose) {
                struct pci_dev *pci_dev;
                pci_dev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, NULL);
                if (pci_dev) {
                        dev->hose = pci_dev->sysdata;
                        pci_dev_put(pci_dev);
                }
                if (!dev->hose) {
                        struct pci_bus *b = pci_bus_b(pci_root_buses.next);
                        if (b)
                                dev->hose = b->sysdata;
                }
        }
#endif

        return 0;
      out_free:
        drm_free(priv, sizeof(*priv), DRM_MEM_FILES);
        filp->private_data = NULL;
        return ret;
}

/** No-op. */
int drm_fasync(int fd, struct file *filp, int on)
{
        struct drm_file *priv = filp->private_data;
        struct drm_device *dev = priv->head->dev;
        int retcode;

        DRM_DEBUG("fd = %d, device = 0x%lx\n", fd,
                  (long)old_encode_dev(priv->head->device));
        retcode = fasync_helper(fd, filp, on, &dev->buf_async);
        if (retcode < 0)
                return retcode;
        return 0;
}
EXPORT_SYMBOL(drm_fasync);

/**
 * Release file.
 *
 * \param inode device inode
 * \param file_priv DRM file private.
 * \return zero on success or a negative number on failure.
 *
 * If the hardware lock is held then free it, and take it again for the kernel
 * context since it's necessary to reclaim buffers. Unlink the file private
 * data from its list and free it. Decreases the open count and if it reaches
 * zero calls drm_lastclose().
 */
int drm_release(struct inode *inode, struct file *filp)
{
        struct drm_file *file_priv = filp->private_data;
        struct drm_device *dev = file_priv->head->dev;
        int retcode = 0;
        unsigned long irqflags;

        lock_kernel();

        DRM_DEBUG("open_count = %d\n", dev->open_count);

        if (dev->driver->preclose)
                dev->driver->preclose(dev, file_priv);

        /* ========================================================
         * Begin inline drm_release
         */

        DRM_DEBUG("pid = %d, device = 0x%lx, open_count = %d\n",
                  task_pid_nr(current),
                  (long)old_encode_dev(file_priv->head->device),
                  dev->open_count);

        if (dev->driver->reclaim_buffers_locked && dev->lock.hw_lock) {
                if (drm_i_have_hw_lock(dev, file_priv)) {
                        dev->driver->reclaim_buffers_locked(dev, file_priv);
                } else {
                        unsigned long _end=jiffies + 3*DRM_HZ;
                        int locked = 0;

                        drm_idlelock_take(&dev->lock);

                        /*
                         * Wait for a while.
                         */

                        do{
                                spin_lock_irqsave(&dev->lock.spinlock,
                                                  irqflags);
                                locked = dev->lock.idle_has_lock;
                                spin_unlock_irqrestore(&dev->lock.spinlock,
                                                       irqflags);
                                if (locked)
                                        break;
                                schedule();
                        } while (!time_after_eq(jiffies, _end));

                        if (!locked) {
                                DRM_ERROR("reclaim_buffers_locked() deadlock. Please rework this\n"
                                          "\tdriver to use reclaim_buffers_idlelocked() instead.\n"
                                          "\tI will go on reclaiming the buffers anyway.\n");
                        }

                        dev->driver->reclaim_buffers_locked(dev, file_priv);
                        drm_idlelock_release(&dev->lock);
                }
        }

        if (dev->driver->reclaim_buffers_idlelocked && dev->lock.hw_lock) {

                drm_idlelock_take(&dev->lock);
                dev->driver->reclaim_buffers_idlelocked(dev, file_priv);
                drm_idlelock_release(&dev->lock);

        }

        if (drm_i_have_hw_lock(dev, file_priv)) {
                DRM_DEBUG("File %p released, freeing lock for context %d\n",
                          filp, _DRM_LOCKING_CONTEXT(dev->lock.hw_lock->lock));

                drm_lock_free(&dev->lock,
                              _DRM_LOCKING_CONTEXT(dev->lock.hw_lock->lock));
        }


        if (drm_core_check_feature(dev, DRIVER_HAVE_DMA) &&
            !dev->driver->reclaim_buffers_locked) {
                dev->driver->reclaim_buffers(dev, file_priv);
        }

        drm_fasync(-1, filp, 0);

        mutex_lock(&dev->ctxlist_mutex);
        if (!list_empty(&dev->ctxlist)) {
                struct drm_ctx_list *pos, *n;

                list_for_each_entry_safe(pos, n, &dev->ctxlist, head) {
                        if (pos->tag == file_priv &&
                            pos->handle != DRM_KERNEL_CONTEXT) {
                                if (dev->driver->context_dtor)
                                        dev->driver->context_dtor(dev,
                                                                  pos->handle);

                                drm_ctxbitmap_free(dev, pos->handle);

                                list_del(&pos->head);
                                drm_free(pos, sizeof(*pos), DRM_MEM_CTXLIST);
                                --dev->ctx_count;
                        }
                }
        }
        mutex_unlock(&dev->ctxlist_mutex);

        mutex_lock(&dev->struct_mutex);
        if (file_priv->remove_auth_on_close == 1) {
                struct drm_file *temp;

                list_for_each_entry(temp, &dev->filelist, lhead)
                        temp->authenticated = 0;
        }
        list_del(&file_priv->lhead);
        mutex_unlock(&dev->struct_mutex);

        if (dev->driver->postclose)
                dev->driver->postclose(dev, file_priv);
        drm_free(file_priv, sizeof(*file_priv), DRM_MEM_FILES);

        /* ========================================================
         * End inline drm_release
         */

        atomic_inc(&dev->counts[_DRM_STAT_CLOSES]);
        spin_lock(&dev->count_lock);
        if (!--dev->open_count) {
                if (atomic_read(&dev->ioctl_count) || dev->blocked) {
                        DRM_ERROR("Device busy: %d %d\n",
                                  atomic_read(&dev->ioctl_count), dev->blocked);
                        spin_unlock(&dev->count_lock);
                        unlock_kernel();
                        return -EBUSY;
                }
                spin_unlock(&dev->count_lock);
                unlock_kernel();
                return drm_lastclose(dev);
        }
        spin_unlock(&dev->count_lock);

        unlock_kernel();

        return retcode;
}
EXPORT_SYMBOL(drm_release);

/** No-op. */
unsigned int drm_poll(struct file *filp, struct poll_table_struct *wait)
{
        return 0;
}
EXPORT_SYMBOL(drm_poll);