/**
 * \file drm_agpsupport.c
 * DRM support for AGP/GART backend
 *
 * \author Rickard E. (Rik) Faith <faith@valinux.com>
 * \author Gareth Hughes <gareth@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 <linux/module.h>
#include <linux/pci.h>
#include <linux/slab.h>

#include <asm/agp.h>

#include <drm/drm_agpsupport.h>
#include <drm/drm_device.h>
#include <drm/drm_drv.h>
#include <drm/drm_file.h>
#include <drm/drm_print.h>

#include "drm_legacy.h"

/**
 * Get AGP information.
 *
 * \param inode device inode.
 * \param file_priv DRM file private.
 * \param cmd command.
 * \param arg pointer to a (output) drm_agp_info structure.
 * \return zero on success or a negative number on failure.
 *
 * Verifies the AGP device has been initialized and acquired and fills in the
 * drm_agp_info structure with the information in drm_agp_head::agp_info.
 */
int drm_agp_info(struct drm_device *dev, struct drm_agp_info *info)
{
        struct agp_kern_info *kern;

        if (!dev->agp || !dev->agp->acquired)
                return -EINVAL;

        kern = &dev->agp->agp_info;
        info->agp_version_major = kern->version.major;
        info->agp_version_minor = kern->version.minor;
        info->mode = kern->mode;
        info->aperture_base = kern->aper_base;
        info->aperture_size = kern->aper_size * 1024 * 1024;
        info->memory_allowed = kern->max_memory << PAGE_SHIFT;
        info->memory_used = kern->current_memory << PAGE_SHIFT;
        info->id_vendor = kern->device->vendor;
        info->id_device = kern->device->device;

        return 0;
}
EXPORT_SYMBOL(drm_agp_info);

int drm_agp_info_ioctl(struct drm_device *dev, void *data,
                       struct drm_file *file_priv)
{
        struct drm_agp_info *info = data;
        int err;

        err = drm_agp_info(dev, info);
        if (err)
                return err;

        return 0;
}

/**
 * Acquire the AGP device.
 *
 * \param dev DRM device that is to acquire AGP.
 * \return zero on success or a negative number on failure.
 *
 * Verifies the AGP device hasn't been acquired before and calls
 * \c agp_backend_acquire.
 */
int drm_agp_acquire(struct drm_device *dev)
{
        if (!dev->agp)
                return -ENODEV;
        if (dev->agp->acquired)
                return -EBUSY;
        dev->agp->bridge = agp_backend_acquire(dev->pdev);
        if (!dev->agp->bridge)
                return -ENODEV;
        dev->agp->acquired = 1;
        return 0;
}
EXPORT_SYMBOL(drm_agp_acquire);

/**
 * Acquire the AGP device (ioctl).
 *
 * \param inode device inode.
 * \param file_priv DRM file private.
 * \param cmd command.
 * \param arg user argument.
 * \return zero on success or a negative number on failure.
 *
 * Verifies the AGP device hasn't been acquired before and calls
 * \c agp_backend_acquire.
 */
int drm_agp_acquire_ioctl(struct drm_device *dev, void *data,
                          struct drm_file *file_priv)
{
        return drm_agp_acquire((struct drm_device *) file_priv->minor->dev);
}

/**
 * Release the AGP device.
 *
 * \param dev DRM device that is to release AGP.
 * \return zero on success or a negative number on failure.
 *
 * Verifies the AGP device has been acquired and calls \c agp_backend_release.
 */
int drm_agp_release(struct drm_device *dev)
{
        if (!dev->agp || !dev->agp->acquired)
                return -EINVAL;
        agp_backend_release(dev->agp->bridge);
        dev->agp->acquired = 0;
        return 0;
}
EXPORT_SYMBOL(drm_agp_release);

int drm_agp_release_ioctl(struct drm_device *dev, void *data,
                          struct drm_file *file_priv)
{
        return drm_agp_release(dev);
}

/**
 * Enable the AGP bus.
 *
 * \param dev DRM device that has previously acquired AGP.
 * \param mode Requested AGP mode.
 * \return zero on success or a negative number on failure.
 *
 * Verifies the AGP device has been acquired but not enabled, and calls
 * \c agp_enable.
 */
int drm_agp_enable(struct drm_device *dev, struct drm_agp_mode mode)
{
        if (!dev->agp || !dev->agp->acquired)
                return -EINVAL;

        dev->agp->mode = mode.mode;
        agp_enable(dev->agp->bridge, mode.mode);
        dev->agp->enabled = 1;
        return 0;
}
EXPORT_SYMBOL(drm_agp_enable);

int drm_agp_enable_ioctl(struct drm_device *dev, void *data,
                         struct drm_file *file_priv)
{
        struct drm_agp_mode *mode = data;

        return drm_agp_enable(dev, *mode);
}

/**
 * Allocate AGP memory.
 *
 * \param inode device inode.
 * \param file_priv file private pointer.
 * \param cmd command.
 * \param arg pointer to a drm_agp_buffer structure.
 * \return zero on success or a negative number on failure.
 *
 * Verifies the AGP device is present and has been acquired, allocates the
 * memory via agp_allocate_memory() and creates a drm_agp_mem entry for it.
 */
int drm_agp_alloc(struct drm_device *dev, struct drm_agp_buffer *request)
{
        struct drm_agp_mem *entry;
        struct agp_memory *memory;
        unsigned long pages;
        u32 type;

        if (!dev->agp || !dev->agp->acquired)
                return -EINVAL;
        entry = kzalloc(sizeof(*entry), GFP_KERNEL);
        if (!entry)
                return -ENOMEM;

        pages = (request->size + PAGE_SIZE - 1) / PAGE_SIZE;
        type = (u32) request->type;
        memory = agp_allocate_memory(dev->agp->bridge, pages, type);
        if (!memory) {
                kfree(entry);
                return -ENOMEM;
        }

        entry->handle = (unsigned long)memory->key + 1;
        entry->memory = memory;
        entry->bound = 0;
        entry->pages = pages;
        list_add(&entry->head, &dev->agp->memory);

        request->handle = entry->handle;
        request->physical = memory->physical;

        return 0;
}
EXPORT_SYMBOL(drm_agp_alloc);


int drm_agp_alloc_ioctl(struct drm_device *dev, void *data,
                        struct drm_file *file_priv)
{
        struct drm_agp_buffer *request = data;

        return drm_agp_alloc(dev, request);
}

/**
 * Search for the AGP memory entry associated with a handle.
 *
 * \param dev DRM device structure.
 * \param handle AGP memory handle.
 * \return pointer to the drm_agp_mem structure associated with \p handle.
 *
 * Walks through drm_agp_head::memory until finding a matching handle.
 */
static struct drm_agp_mem *drm_agp_lookup_entry(struct drm_device *dev,
                                                unsigned long handle)
{
        struct drm_agp_mem *entry;

        list_for_each_entry(entry, &dev->agp->memory, head) {
                if (entry->handle == handle)
                        return entry;
        }
        return NULL;
}

/**
 * Unbind AGP memory from the GATT (ioctl).
 *
 * \param inode device inode.
 * \param file_priv DRM file private.
 * \param cmd command.
 * \param arg pointer to a drm_agp_binding structure.
 * \return zero on success or a negative number on failure.
 *
 * Verifies the AGP device is present and acquired, looks-up the AGP memory
 * entry and passes it to the unbind_agp() function.
 */
int drm_agp_unbind(struct drm_device *dev, struct drm_agp_binding *request)
{
        struct drm_agp_mem *entry;
        int ret;

        if (!dev->agp || !dev->agp->acquired)
                return -EINVAL;
        entry = drm_agp_lookup_entry(dev, request->handle);
        if (!entry || !entry->bound)
                return -EINVAL;
        ret = drm_unbind_agp(entry->memory);
        if (ret == 0)
                entry->bound = 0;
        return ret;
}
EXPORT_SYMBOL(drm_agp_unbind);


int drm_agp_unbind_ioctl(struct drm_device *dev, void *data,
                         struct drm_file *file_priv)
{
        struct drm_agp_binding *request = data;

        return drm_agp_unbind(dev, request);
}

/**
 * Bind AGP memory into the GATT (ioctl)
 *
 * \param inode device inode.
 * \param file_priv DRM file private.
 * \param cmd command.
 * \param arg pointer to a drm_agp_binding structure.
 * \return zero on success or a negative number on failure.
 *
 * Verifies the AGP device is present and has been acquired and that no memory
 * is currently bound into the GATT. Looks-up the AGP memory entry and passes
 * it to bind_agp() function.
 */
int drm_agp_bind(struct drm_device *dev, struct drm_agp_binding *request)
{
        struct drm_agp_mem *entry;
        int retcode;
        int page;

        if (!dev->agp || !dev->agp->acquired)
                return -EINVAL;
        entry = drm_agp_lookup_entry(dev, request->handle);
        if (!entry || entry->bound)
                return -EINVAL;
        page = (request->offset + PAGE_SIZE - 1) / PAGE_SIZE;
        retcode = drm_bind_agp(entry->memory, page);
        if (retcode)
                return retcode;
        entry->bound = dev->agp->base + (page << PAGE_SHIFT);
        DRM_DEBUG("base = 0x%lx entry->bound = 0x%lx\n",
                  dev->agp->base, entry->bound);
        return 0;
}
EXPORT_SYMBOL(drm_agp_bind);


int drm_agp_bind_ioctl(struct drm_device *dev, void *data,
                       struct drm_file *file_priv)
{
        struct drm_agp_binding *request = data;

        return drm_agp_bind(dev, request);
}

/**
 * Free AGP memory (ioctl).
 *
 * \param inode device inode.
 * \param file_priv DRM file private.
 * \param cmd command.
 * \param arg pointer to a drm_agp_buffer structure.
 * \return zero on success or a negative number on failure.
 *
 * Verifies the AGP device is present and has been acquired and looks up the
 * AGP memory entry. If the memory is currently bound, unbind it via
 * unbind_agp(). Frees it via free_agp() as well as the entry itself
 * and unlinks from the doubly linked list it's inserted in.
 */
int drm_agp_free(struct drm_device *dev, struct drm_agp_buffer *request)
{
        struct drm_agp_mem *entry;

        if (!dev->agp || !dev->agp->acquired)
                return -EINVAL;
        entry = drm_agp_lookup_entry(dev, request->handle);
        if (!entry)
                return -EINVAL;
        if (entry->bound)
                drm_unbind_agp(entry->memory);

        list_del(&entry->head);

        drm_free_agp(entry->memory, entry->pages);
        kfree(entry);
        return 0;
}
EXPORT_SYMBOL(drm_agp_free);


int drm_agp_free_ioctl(struct drm_device *dev, void *data,
                       struct drm_file *file_priv)
{
        struct drm_agp_buffer *request = data;

        return drm_agp_free(dev, request);
}

/**
 * Initialize the AGP resources.
 *
 * \return pointer to a drm_agp_head structure.
 *
 * Gets the drm_agp_t structure which is made available by the agpgart module
 * via the inter_module_* functions. Creates and initializes a drm_agp_head
 * structure.
 *
 * Note that final cleanup of the kmalloced structure is directly done in
 * drm_pci_agp_destroy.
 */
struct drm_agp_head *drm_agp_init(struct drm_device *dev)
{
        struct drm_agp_head *head = NULL;

        head = kzalloc(sizeof(*head), GFP_KERNEL);
        if (!head)
                return NULL;
        head->bridge = agp_find_bridge(dev->pdev);
        if (!head->bridge) {
                head->bridge = agp_backend_acquire(dev->pdev);
                if (!head->bridge) {
                        kfree(head);
                        return NULL;
                }
                agp_copy_info(head->bridge, &head->agp_info);
                agp_backend_release(head->bridge);
        } else {
                agp_copy_info(head->bridge, &head->agp_info);
        }
        if (head->agp_info.chipset == NOT_SUPPORTED) {
                kfree(head);
                return NULL;
        }
        INIT_LIST_HEAD(&head->memory);
        head->cant_use_aperture = head->agp_info.cant_use_aperture;
        head->page_mask = head->agp_info.page_mask;
        head->base = head->agp_info.aper_base;
        return head;
}
/* Only exported for i810.ko */
EXPORT_SYMBOL(drm_agp_init);

/**
 * drm_legacy_agp_clear - Clear AGP resource list
 * @dev: DRM device
 *
 * Iterate over all AGP resources and remove them. But keep the AGP head
 * intact so it can still be used. It is safe to call this if AGP is disabled or
 * was already removed.
 *
 * Cleanup is only done for drivers who have DRIVER_LEGACY set.
 */
void drm_legacy_agp_clear(struct drm_device *dev)
{
        struct drm_agp_mem *entry, *tempe;

        if (!dev->agp)
                return;
        if (!drm_core_check_feature(dev, DRIVER_LEGACY))
                return;

        list_for_each_entry_safe(entry, tempe, &dev->agp->memory, head) {
                if (entry->bound)
                        drm_unbind_agp(entry->memory);
                drm_free_agp(entry->memory, entry->pages);
                kfree(entry);
        }
        INIT_LIST_HEAD(&dev->agp->memory);

        if (dev->agp->acquired)
                drm_agp_release(dev);

        dev->agp->acquired = 0;
        dev->agp->enabled = 0;
}

/**
 * Binds a collection of pages into AGP memory at the given offset, returning
 * the AGP memory structure containing them.
 *
 * No reference is held on the pages during this time -- it is up to the
 * caller to handle that.
 */
struct agp_memory *
drm_agp_bind_pages(struct drm_device *dev,
                   struct page **pages,
                   unsigned long num_pages,
                   uint32_t gtt_offset,
                   u32 type)
{
        struct agp_memory *mem;
        int ret, i;

        DRM_DEBUG("\n");

        mem = agp_allocate_memory(dev->agp->bridge, num_pages,
                                      type);
        if (mem == NULL) {
                DRM_ERROR("Failed to allocate memory for %ld pages\n",
                          num_pages);
                return NULL;
        }

        for (i = 0; i < num_pages; i++)
                mem->pages[i] = pages[i];
        mem->page_count = num_pages;

        mem->is_flushed = true;
        ret = agp_bind_memory(mem, gtt_offset / PAGE_SIZE);
        if (ret != 0) {
                DRM_ERROR("Failed to bind AGP memory: %d\n", ret);
                agp_free_memory(mem);
                return NULL;
        }

        return mem;
}
EXPORT_SYMBOL(drm_agp_bind_pages);