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[tomato.git] / release / src-rt-6.x / linux / linux-2.6 / drivers / char / drm / drm_context.c

/**
 * \file drm_context.c
 * IOCTLs for generic contexts
 *
 * \author Rickard E. (Rik) Faith <faith@valinux.com>
 * \author Gareth Hughes <gareth@valinux.com>
 */

/*
 * Created: Fri Nov 24 18:31:37 2000 by gareth@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.
 */

/*
 * ChangeLog:
 *  2001-11-16  Torsten Duwe <duwe@caldera.de>
 *              added context constructor/destructor hooks,
 *              needed by SiS driver's memory management.
 */

#include "drmP.h"

/******************************************************************/
/** \name Context bitmap support */
/*@{*/

/**
 * Free a handle from the context bitmap.
 *
 * \param dev DRM device.
 * \param ctx_handle context handle.
 *
 * Clears the bit specified by \p ctx_handle in drm_device::ctx_bitmap and the entry
 * in drm_device::context_sareas, while holding the drm_device::struct_mutex
 * lock.
 */
void drm_ctxbitmap_free(drm_device_t * dev, int ctx_handle)
{
        if (ctx_handle < 0)
                goto failed;
        if (!dev->ctx_bitmap)
                goto failed;

        if (ctx_handle < DRM_MAX_CTXBITMAP) {
                mutex_lock(&dev->struct_mutex);
                clear_bit(ctx_handle, dev->ctx_bitmap);
                dev->context_sareas[ctx_handle] = NULL;
                mutex_unlock(&dev->struct_mutex);
                return;
        }
      failed:
        DRM_ERROR("Attempt to free invalid context handle: %d\n", ctx_handle);
        return;
}

/**
 * Context bitmap allocation.
 *
 * \param dev DRM device.
 * \return (non-negative) context handle on success or a negative number on failure.
 *
 * Find the first zero bit in drm_device::ctx_bitmap and (re)allocates
 * drm_device::context_sareas to accommodate the new entry while holding the
 * drm_device::struct_mutex lock.
 */
static int drm_ctxbitmap_next(drm_device_t * dev)
{
        int bit;

        if (!dev->ctx_bitmap)
                return -1;

        mutex_lock(&dev->struct_mutex);
        bit = find_first_zero_bit(dev->ctx_bitmap, DRM_MAX_CTXBITMAP);
        if (bit < DRM_MAX_CTXBITMAP) {
                set_bit(bit, dev->ctx_bitmap);
                DRM_DEBUG("drm_ctxbitmap_next bit : %d\n", bit);
                if ((bit + 1) > dev->max_context) {
                        dev->max_context = (bit + 1);
                        if (dev->context_sareas) {
                                drm_map_t **ctx_sareas;

                                ctx_sareas = drm_realloc(dev->context_sareas,
                                                         (dev->max_context -
                                                          1) *
                                                         sizeof(*dev->
                                                                context_sareas),
                                                         dev->max_context *
                                                         sizeof(*dev->
                                                                context_sareas),
                                                         DRM_MEM_MAPS);
                                if (!ctx_sareas) {
                                        clear_bit(bit, dev->ctx_bitmap);
                                        mutex_unlock(&dev->struct_mutex);
                                        return -1;
                                }
                                dev->context_sareas = ctx_sareas;
                                dev->context_sareas[bit] = NULL;
                        } else {
                                /* max_context == 1 at this point */
                                dev->context_sareas =
                                    drm_alloc(dev->max_context *
                                              sizeof(*dev->context_sareas),
                                              DRM_MEM_MAPS);
                                if (!dev->context_sareas) {
                                        clear_bit(bit, dev->ctx_bitmap);
                                        mutex_unlock(&dev->struct_mutex);
                                        return -1;
                                }
                                dev->context_sareas[bit] = NULL;
                        }
                }
                mutex_unlock(&dev->struct_mutex);
                return bit;
        }
        mutex_unlock(&dev->struct_mutex);
        return -1;
}

/**
 * Context bitmap initialization.
 *
 * \param dev DRM device.
 *
 * Allocates and initialize drm_device::ctx_bitmap and drm_device::context_sareas, while holding
 * the drm_device::struct_mutex lock.
 */
int drm_ctxbitmap_init(drm_device_t * dev)
{
        int i;
        int temp;

        mutex_lock(&dev->struct_mutex);
        dev->ctx_bitmap = (unsigned long *)drm_alloc(PAGE_SIZE,
                                                     DRM_MEM_CTXBITMAP);
        if (dev->ctx_bitmap == NULL) {
                mutex_unlock(&dev->struct_mutex);
                return -ENOMEM;
        }
        memset((void *)dev->ctx_bitmap, 0, PAGE_SIZE);
        dev->context_sareas = NULL;
        dev->max_context = -1;
        mutex_unlock(&dev->struct_mutex);

        for (i = 0; i < DRM_RESERVED_CONTEXTS; i++) {
                temp = drm_ctxbitmap_next(dev);
                DRM_DEBUG("drm_ctxbitmap_init : %d\n", temp);
        }

        return 0;
}

/**
 * Context bitmap cleanup.
 *
 * \param dev DRM device.
 *
 * Frees drm_device::ctx_bitmap and drm_device::context_sareas, while holding
 * the drm_device::struct_mutex lock.
 */
void drm_ctxbitmap_cleanup(drm_device_t * dev)
{
        mutex_lock(&dev->struct_mutex);
        if (dev->context_sareas)
                drm_free(dev->context_sareas,
                         sizeof(*dev->context_sareas) *
                         dev->max_context, DRM_MEM_MAPS);
        drm_free((void *)dev->ctx_bitmap, PAGE_SIZE, DRM_MEM_CTXBITMAP);
        mutex_unlock(&dev->struct_mutex);
}

/*@}*/

/******************************************************************/
/** \name Per Context SAREA Support */
/*@{*/

/**
 * Get per-context SAREA.
 *
 * \param inode device inode.
 * \param filp file pointer.
 * \param cmd command.
 * \param arg user argument pointing to a drm_ctx_priv_map structure.
 * \return zero on success or a negative number on failure.
 *
 * Gets the map from drm_device::context_sareas with the handle specified and
 * returns its handle.
 */
int drm_getsareactx(struct inode *inode, struct file *filp,
                    unsigned int cmd, unsigned long arg)
{
        drm_file_t *priv = filp->private_data;
        drm_device_t *dev = priv->head->dev;
        drm_ctx_priv_map_t __user *argp = (void __user *)arg;
        drm_ctx_priv_map_t request;
        drm_map_t *map;
        drm_map_list_t *_entry;

        if (copy_from_user(&request, argp, sizeof(request)))
                return -EFAULT;

        mutex_lock(&dev->struct_mutex);
        if (dev->max_context < 0
            || request.ctx_id >= (unsigned)dev->max_context) {
                mutex_unlock(&dev->struct_mutex);
                return -EINVAL;
        }

        map = dev->context_sareas[request.ctx_id];
        mutex_unlock(&dev->struct_mutex);

        request.handle = NULL;
        list_for_each_entry(_entry, &dev->maplist->head, head) {
                if (_entry->map == map) {
                        request.handle =
                            (void *)(unsigned long)_entry->user_token;
                        break;
                }
        }
        if (request.handle == NULL)
                return -EINVAL;

        if (copy_to_user(argp, &request, sizeof(request)))
                return -EFAULT;
        return 0;
}

/**
 * Set per-context SAREA.
 *
 * \param inode device inode.
 * \param filp file pointer.
 * \param cmd command.
 * \param arg user argument pointing to a drm_ctx_priv_map structure.
 * \return zero on success or a negative number on failure.
 *
 * Searches the mapping specified in \p arg and update the entry in
 * drm_device::context_sareas with it.
 */
int drm_setsareactx(struct inode *inode, struct file *filp,
                    unsigned int cmd, unsigned long arg)
{
        drm_file_t *priv = filp->private_data;
        drm_device_t *dev = priv->head->dev;
        drm_ctx_priv_map_t request;
        drm_map_t *map = NULL;
        drm_map_list_t *r_list = NULL;
        struct list_head *list;

        if (copy_from_user(&request,
                           (drm_ctx_priv_map_t __user *) arg, sizeof(request)))
                return -EFAULT;

        mutex_lock(&dev->struct_mutex);
        list_for_each(list, &dev->maplist->head) {
                r_list = list_entry(list, drm_map_list_t, head);
                if (r_list->map
                    && r_list->user_token == (unsigned long)request.handle)
                        goto found;
        }
      bad:
        mutex_unlock(&dev->struct_mutex);
        return -EINVAL;

      found:
        map = r_list->map;
        if (!map)
                goto bad;
        if (dev->max_context < 0)
                goto bad;
        if (request.ctx_id >= (unsigned)dev->max_context)
                goto bad;
        dev->context_sareas[request.ctx_id] = map;
        mutex_unlock(&dev->struct_mutex);
        return 0;
}

/*@}*/

/******************************************************************/
/** \name The actual DRM context handling routines */
/*@{*/

/**
 * Switch context.
 *
 * \param dev DRM device.
 * \param old old context handle.
 * \param new new context handle.
 * \return zero on success or a negative number on failure.
 *
 * Attempt to set drm_device::context_flag.
 */
static int drm_context_switch(drm_device_t * dev, int old, int new)
{
        if (test_and_set_bit(0, &dev->context_flag)) {
                DRM_ERROR("Reentering -- FIXME\n");
                return -EBUSY;
        }

        DRM_DEBUG("Context switch from %d to %d\n", old, new);

        if (new == dev->last_context) {
                clear_bit(0, &dev->context_flag);
                return 0;
        }

        return 0;
}

/**
 * Complete context switch.
 *
 * \param dev DRM device.
 * \param new new context handle.
 * \return zero on success or a negative number on failure.
 *
 * Updates drm_device::last_context and drm_device::last_switch. Verifies the
 * hardware lock is held, clears the drm_device::context_flag and wakes up
 * drm_device::context_wait.
 */
static int drm_context_switch_complete(drm_device_t * dev, int new)
{
        dev->last_context = new;        /* PRE/POST: This is the _only_ writer. */
        dev->last_switch = jiffies;

        if (!_DRM_LOCK_IS_HELD(dev->lock.hw_lock->lock)) {
                DRM_ERROR("Lock isn't held after context switch\n");
        }

        /* If a context switch is ever initiated
           when the kernel holds the lock, release
           that lock here. */
        clear_bit(0, &dev->context_flag);
        wake_up(&dev->context_wait);

        return 0;
}

/**
 * Reserve contexts.
 *
 * \param inode device inode.
 * \param filp file pointer.
 * \param cmd command.
 * \param arg user argument pointing to a drm_ctx_res structure.
 * \return zero on success or a negative number on failure.
 */
int drm_resctx(struct inode *inode, struct file *filp,
               unsigned int cmd, unsigned long arg)
{
        drm_ctx_res_t res;
        drm_ctx_t __user *argp = (void __user *)arg;
        drm_ctx_t ctx;
        int i;

        if (copy_from_user(&res, argp, sizeof(res)))
                return -EFAULT;

        if (res.count >= DRM_RESERVED_CONTEXTS) {
                memset(&ctx, 0, sizeof(ctx));
                for (i = 0; i < DRM_RESERVED_CONTEXTS; i++) {
                        ctx.handle = i;
                        if (copy_to_user(&res.contexts[i], &ctx, sizeof(ctx)))
                                return -EFAULT;
                }
        }
        res.count = DRM_RESERVED_CONTEXTS;

        if (copy_to_user(argp, &res, sizeof(res)))
                return -EFAULT;
        return 0;
}

/**
 * Add context.
 *
 * \param inode device inode.
 * \param filp file pointer.
 * \param cmd command.
 * \param arg user argument pointing to a drm_ctx structure.
 * \return zero on success or a negative number on failure.
 *
 * Get a new handle for the context and copy to userspace.
 */
int drm_addctx(struct inode *inode, struct file *filp,
               unsigned int cmd, unsigned long arg)
{
        drm_file_t *priv = filp->private_data;
        drm_device_t *dev = priv->head->dev;
        drm_ctx_list_t *ctx_entry;
        drm_ctx_t __user *argp = (void __user *)arg;
        drm_ctx_t ctx;

        if (copy_from_user(&ctx, argp, sizeof(ctx)))
                return -EFAULT;

        ctx.handle = drm_ctxbitmap_next(dev);
        if (ctx.handle == DRM_KERNEL_CONTEXT) {
                /* Skip kernel's context and get a new one. */
                ctx.handle = drm_ctxbitmap_next(dev);
        }
        DRM_DEBUG("%d\n", ctx.handle);
        if (ctx.handle == -1) {
                DRM_DEBUG("Not enough free contexts.\n");
                /* Should this return -EBUSY instead? */
                return -ENOMEM;
        }

        if (ctx.handle != DRM_KERNEL_CONTEXT) {
                if (dev->driver->context_ctor)
                        if (!dev->driver->context_ctor(dev, ctx.handle)) {
                                DRM_DEBUG("Running out of ctxs or memory.\n");
                                return -ENOMEM;
                        }
        }

        ctx_entry = drm_alloc(sizeof(*ctx_entry), DRM_MEM_CTXLIST);
        if (!ctx_entry) {
                DRM_DEBUG("out of memory\n");
                return -ENOMEM;
        }

        INIT_LIST_HEAD(&ctx_entry->head);
        ctx_entry->handle = ctx.handle;
        ctx_entry->tag = priv;

        mutex_lock(&dev->ctxlist_mutex);
        list_add(&ctx_entry->head, &dev->ctxlist->head);
        ++dev->ctx_count;
        mutex_unlock(&dev->ctxlist_mutex);

        if (copy_to_user(argp, &ctx, sizeof(ctx)))
                return -EFAULT;
        return 0;
}

int drm_modctx(struct inode *inode, struct file *filp,
               unsigned int cmd, unsigned long arg)
{
        /* This does nothing */
        return 0;
}

/**
 * Get context.
 *
 * \param inode device inode.
 * \param filp file pointer.
 * \param cmd command.
 * \param arg user argument pointing to a drm_ctx structure.
 * \return zero on success or a negative number on failure.
 */
int drm_getctx(struct inode *inode, struct file *filp,
               unsigned int cmd, unsigned long arg)
{
        drm_ctx_t __user *argp = (void __user *)arg;
        drm_ctx_t ctx;

        if (copy_from_user(&ctx, argp, sizeof(ctx)))
                return -EFAULT;

        /* This is 0, because we don't handle any context flags */
        ctx.flags = 0;

        if (copy_to_user(argp, &ctx, sizeof(ctx)))
                return -EFAULT;
        return 0;
}

/**
 * Switch context.
 *
 * \param inode device inode.
 * \param filp file pointer.
 * \param cmd command.
 * \param arg user argument pointing to a drm_ctx structure.
 * \return zero on success or a negative number on failure.
 *
 * Calls context_switch().
 */
int drm_switchctx(struct inode *inode, struct file *filp,
                  unsigned int cmd, unsigned long arg)
{
        drm_file_t *priv = filp->private_data;
        drm_device_t *dev = priv->head->dev;
        drm_ctx_t ctx;

        if (copy_from_user(&ctx, (drm_ctx_t __user *) arg, sizeof(ctx)))
                return -EFAULT;

        DRM_DEBUG("%d\n", ctx.handle);
        return drm_context_switch(dev, dev->last_context, ctx.handle);
}

/**
 * New context.
 *
 * \param inode device inode.
 * \param filp file pointer.
 * \param cmd command.
 * \param arg user argument pointing to a drm_ctx structure.
 * \return zero on success or a negative number on failure.
 *
 * Calls context_switch_complete().
 */
int drm_newctx(struct inode *inode, struct file *filp,
               unsigned int cmd, unsigned long arg)
{
        drm_file_t *priv = filp->private_data;
        drm_device_t *dev = priv->head->dev;
        drm_ctx_t ctx;

        if (copy_from_user(&ctx, (drm_ctx_t __user *) arg, sizeof(ctx)))
                return -EFAULT;

        DRM_DEBUG("%d\n", ctx.handle);
        drm_context_switch_complete(dev, ctx.handle);

        return 0;
}

/**
 * Remove context.
 *
 * \param inode device inode.
 * \param filp file pointer.
 * \param cmd command.
 * \param arg user argument pointing to a drm_ctx structure.
 * \return zero on success or a negative number on failure.
 *
 * If not the special kernel context, calls ctxbitmap_free() to free the specified context.
 */
int drm_rmctx(struct inode *inode, struct file *filp,
              unsigned int cmd, unsigned long arg)
{
        drm_file_t *priv = filp->private_data;
        drm_device_t *dev = priv->head->dev;
        drm_ctx_t ctx;

        if (copy_from_user(&ctx, (drm_ctx_t __user *) arg, sizeof(ctx)))
                return -EFAULT;

        DRM_DEBUG("%d\n", ctx.handle);
        if (ctx.handle == DRM_KERNEL_CONTEXT + 1) {
                priv->remove_auth_on_close = 1;
        }
        if (ctx.handle != DRM_KERNEL_CONTEXT) {
                if (dev->driver->context_dtor)
                        dev->driver->context_dtor(dev, ctx.handle);
                drm_ctxbitmap_free(dev, ctx.handle);
        }

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

                list_for_each_entry_safe(pos, n, &dev->ctxlist->head, head) {
                        if (pos->handle == ctx.handle) {
                                list_del(&pos->head);
                                drm_free(pos, sizeof(*pos), DRM_MEM_CTXLIST);
                                --dev->ctx_count;
                        }
                }
        }
        mutex_unlock(&dev->ctxlist_mutex);

        return 0;
}

/*@}*/