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/* drm_fops.h -- File operations for DRM -*- linux-c -*-

 * 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.

 *

 * Authors:

 *    Rickard E. (Rik) Faith <faith@valinux.com>

 *    Daryll Strauss <daryll@valinux.com>

 *    Gareth Hughes <gareth@valinux.com>

 */

#include "drmP.h"

#include <linux/poll.h>

/* drm_open is called whenever a process opens /dev/drm. */

int DRM(open_helper)(struct inode *inode, struct file *filp, drm_device_t *dev)

{

        int          minor = minor(inode->i_rdev);

        drm_file_t   *priv;

        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->dev           = dev;

        priv->ioctl_count   = 0;

        priv->authenticated = capable(CAP_SYS_ADMIN);

        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_find_class(PCI_CLASS_DISPLAY_VGA << 8, NULL);

                if (pci_dev) dev->hose = pci_dev->sysdata;

                if (!dev->hose) {

                        struct pci_bus *b = pci_bus_b(pci_root_buses.next);

                        if (b) dev->hose = b->sysdata;

                }

        }

#endif

        return 0;

}

int DRM(flush)(struct file *filp)

{

        drm_file_t    *priv   = filp->private_data;

        drm_device_t  *dev    = priv->dev;

        DRM_DEBUG("pid = %d, device = 0x%lx, open_count = %d\n",

                  current->pid, (long)dev->device, dev->open_count);

        return 0;

}

int DRM(fasync)(int fd, struct file *filp, int on)

{

        drm_file_t    *priv   = filp->private_data;

        drm_device_t  *dev    = priv->dev;

        int           retcode;

        DRM_DEBUG("fd = %d, device = 0x%lx\n", fd, (long)dev->device);

        retcode = fasync_helper(fd, filp, on, &dev->buf_async);

        if (retcode < 0) return retcode;

        return 0;

}

/* The drm_read and drm_write_string code (especially that which manages

   the circular buffer), is based on Alessandro Rubini's LINUX DEVICE

   DRIVERS (Cambridge: O'Reilly, 1998), pages 111-113. */

ssize_t DRM(read)(struct file *filp, char *buf, size_t count, loff_t *off)

{

        drm_file_t    *priv   = filp->private_data;

        drm_device_t  *dev    = priv->dev;

        int           left;

        int           avail;

        int           send;

        int           cur;

        DECLARE_WAITQUEUE(wait, current);

        DRM_DEBUG("%p, %p\n", dev->buf_rp, dev->buf_wp);

        add_wait_queue(&dev->buf_readers, &wait);

        set_current_state(TASK_INTERRUPTIBLE);

        while (dev->buf_rp == dev->buf_wp) {

                DRM_DEBUG("  sleeping\n");

                if (filp->f_flags & O_NONBLOCK) {

                        remove_wait_queue(&dev->buf_readers, &wait);

                        set_current_state(TASK_RUNNING);

                        return -EAGAIN;

                }

                schedule(); /* wait for dev->buf_readers */

                if (signal_pending(current)) {

                        DRM_DEBUG("  interrupted\n");

                        remove_wait_queue(&dev->buf_readers, &wait);

                        set_current_state(TASK_RUNNING);

                        return -ERESTARTSYS;

                }

                DRM_DEBUG("  awake\n");

                set_current_state(TASK_INTERRUPTIBLE);

        }

        remove_wait_queue(&dev->buf_readers, &wait);

        set_current_state(TASK_RUNNING);

        left  = (dev->buf_rp + DRM_BSZ - dev->buf_wp) % DRM_BSZ;

        avail = DRM_BSZ - left;

        send  = DRM_MIN(avail, count);

        while (send) {

                if (dev->buf_wp > dev->buf_rp) {

                        cur = DRM_MIN(send, dev->buf_wp - dev->buf_rp);

                } else {

                        cur = DRM_MIN(send, dev->buf_end - dev->buf_rp);

                }

                if (copy_to_user(buf, dev->buf_rp, cur))

                        return -EFAULT;

                dev->buf_rp += cur;

                if (dev->buf_rp == dev->buf_end) dev->buf_rp = dev->buf;

                send -= cur;

        }

        wake_up_interruptible(&dev->buf_writers);

        return DRM_MIN(avail, count);;

}

int DRM(write_string)(drm_device_t *dev, const char *s)

{

        int left   = (dev->buf_rp + DRM_BSZ - dev->buf_wp) % DRM_BSZ;

        int send   = strlen(s);

        int count;

        DRM_DEBUG("%d left, %d to send (%p, %p)\n",

                  left, send, dev->buf_rp, dev->buf_wp);

        if (left == 1 || dev->buf_wp != dev->buf_rp) {

                DRM_ERROR("Buffer not empty (%d left, wp = %p, rp = %p)\n",

                          left,

                          dev->buf_wp,

                          dev->buf_rp);

        }

        while (send) {

                if (dev->buf_wp >= dev->buf_rp) {

                        count = DRM_MIN(send, dev->buf_end - dev->buf_wp);

                        if (count == left) --count; /* Leave a hole */

                } else {

                        count = DRM_MIN(send, dev->buf_rp - dev->buf_wp - 1);

                }

                strncpy(dev->buf_wp, s, count);

                dev->buf_wp += count;

                if (dev->buf_wp == dev->buf_end) dev->buf_wp = dev->buf;

                send -= count;

        }

        if (dev->buf_async) kill_fasync(&dev->buf_async, SIGIO, POLL_IN);

        DRM_DEBUG("waking\n");

        wake_up_interruptible(&dev->buf_readers);

        return 0;

}

unsigned int DRM(poll)(struct file *filp, struct poll_table_struct *wait)

{

        drm_file_t   *priv = filp->private_data;

        drm_device_t *dev  = priv->dev;

        poll_wait(filp, &dev->buf_readers, wait);

        if (dev->buf_wp != dev->buf_rp) return POLLIN | POLLRDNORM;

        return 0;

}