[CONNECTOR]: Update documentation to match reality.

[linux-2.6/verdex.git] / drivers / char / drm / drm_fops.c

/**
 * \file drm_fops.h 
 * 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 <linux/poll.h>

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

static int drm_setup( drm_device_t *dev )
{
        int i;
        int ret;

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

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

        for ( i = 0 ; i < DRM_HASH_SIZE ; i++ ) {
                dev->magiclist[i].head = NULL;
                dev->magiclist[i].tail = NULL;
        }

        dev->ctxlist = drm_alloc(sizeof(*dev->ctxlist),
                                  DRM_MEM_CTXLIST);
        if(dev->ctxlist == NULL) return -ENOMEM;
        memset(dev->ctxlist, 0, sizeof(*dev->ctxlist));
        INIT_LIST_HEAD(&dev->ctxlist->head);

        dev->vmalist = NULL;
        dev->sigdata.lock = dev->lock.hw_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_rp = dev->buf;
        dev->buf_wp = dev->buf;
        dev->buf_end = dev->buf + DRM_BSZ;
        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.
         */
        if (dev->driver->postsetup)
                dev->driver->postsetup(dev);

        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 )
{
        drm_device_t *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);

/**
 * Release file.
 *
 * \param inode device inode
 * \param filp file pointer.
 * \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 takedown().
 */
int drm_release( struct inode *inode, struct file *filp )
{
        drm_file_t *priv = filp->private_data;
        drm_device_t *dev;
        int retcode = 0;

        lock_kernel();
        dev = priv->head->dev;

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

        if (dev->driver->prerelease)
                dev->driver->prerelease(dev, filp);

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

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

        if ( priv->lock_count && dev->lock.hw_lock &&
             _DRM_LOCK_IS_HELD(dev->lock.hw_lock->lock) &&
             dev->lock.filp == filp ) {
                DRM_DEBUG( "File %p released, freeing lock for context %d\n",
                        filp,
                        _DRM_LOCKING_CONTEXT(dev->lock.hw_lock->lock) );
                
                if (dev->driver->release)
                        dev->driver->release(dev, filp);

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

                                /* FIXME: may require heavy-handed reset of
                                   hardware at this point, possibly
                                   processed via a callback to the X
                                   server. */
        }
        else if ( dev->driver->release && priv->lock_count && dev->lock.hw_lock ) {
                /* The lock is required to reclaim buffers */
                DECLARE_WAITQUEUE( entry, current );

                add_wait_queue( &dev->lock.lock_queue, &entry );
                for (;;) {
                        __set_current_state(TASK_INTERRUPTIBLE);
                        if ( !dev->lock.hw_lock ) {
                                /* Device has been unregistered */
                                retcode = -EINTR;
                                break;
                        }
                        if ( drm_lock_take( &dev->lock.hw_lock->lock,
                                             DRM_KERNEL_CONTEXT ) ) {
                                dev->lock.filp      = filp;
                                dev->lock.lock_time = jiffies;
                                atomic_inc( &dev->counts[_DRM_STAT_LOCKS] );
                                break;  /* Got lock */
                        }
                                /* Contention */
                        schedule();
                        if ( signal_pending( current ) ) {
                                retcode = -ERESTARTSYS;
                                break;
                        }
                }
                __set_current_state(TASK_RUNNING);
                remove_wait_queue( &dev->lock.lock_queue, &entry );
                if( !retcode ) {
                        if (dev->driver->release)
                                dev->driver->release(dev, filp);
                        drm_lock_free( dev, &dev->lock.hw_lock->lock,
                                        DRM_KERNEL_CONTEXT );
                }
        }
        
        if (drm_core_check_feature(dev, DRIVER_HAVE_DMA) && !dev->driver->release)
        {
                dev->driver->reclaim_buffers(dev, filp);
        }

        drm_fasync( -1, filp, 0 );

        down( &dev->ctxlist_sem );
        if ( dev->ctxlist && (!list_empty(&dev->ctxlist->head))) {
                drm_ctx_list_t *pos, *n;

                list_for_each_entry_safe( pos, n, &dev->ctxlist->head, head ) {
                        if ( pos->tag == 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;
                        }
                }
        }
        up( &dev->ctxlist_sem );

        down( &dev->struct_sem );
        if ( priv->remove_auth_on_close == 1 ) {
                drm_file_t *temp = dev->file_first;
                while ( temp ) {
                        temp->authenticated = 0;
                        temp = temp->next;
                }
        }
        if ( priv->prev ) {
                priv->prev->next = priv->next;
        } else {
                dev->file_first  = priv->next;
        }
        if ( priv->next ) {
                priv->next->prev = priv->prev;
        } else {
                dev->file_last   = priv->prev;
        }
        up( &dev->struct_sem );
        
        if (dev->driver->free_filp_priv)
                dev->driver->free_filp_priv(dev, priv);

        drm_free( priv, sizeof(*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_takedown( dev );
        }
        spin_unlock( &dev->count_lock );

        unlock_kernel();

        return retcode;
}
EXPORT_SYMBOL(drm_release);

/**
 * 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, drm_device_t *dev)
{
        int          minor = iminor(inode);
        drm_file_t   *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", current->pid, minor);

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

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

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

        down(&dev->struct_sem);
        if (!dev->file_last) {
                priv->next      = NULL;
                priv->prev      = NULL;
                dev->file_first = priv;
                dev->file_last  = priv;
        } else {
                priv->next           = NULL;
                priv->prev           = dev->file_last;
                dev->file_last->next = priv;
                dev->file_last       = priv;
        }
        up(&dev->struct_sem);

#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_flush(struct file *filp)
{
        drm_file_t    *priv   = filp->private_data;
        drm_device_t  *dev    = priv->head->dev;

        DRM_DEBUG("pid = %d, device = 0x%lx, open_count = %d\n",
                  current->pid, (long)old_encode_dev(priv->head->device), dev->open_count);
        return 0;
}
EXPORT_SYMBOL(drm_flush);

/** No-op. */
int drm_fasync(int fd, struct file *filp, int on)
{
        drm_file_t    *priv   = filp->private_data;
        drm_device_t  *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);

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