gem.c

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/*
 *  psb GEM interface
 *
 * Copyright (c) 2011, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Authors: Alan Cox
 *
 * TODO:
 *  -   we need to work out if the MMU is relevant (eg for
 *      accelerated operations on a GEM object)
 */

#include <drm/drmP.h>
#include <drm/drm.h>
#include <drm/gma_drm.h>
#include "psb_drv.h"

int psb_gem_init_object(struct drm_gem_object *obj)
{
    return -EINVAL;
}

void psb_gem_free_object(struct drm_gem_object *obj)
{
    struct gtt_range *gtt = container_of(obj, struct gtt_range, gem);

    /* Remove the list map if one is present */
    if (obj->map_list.map)
        drm_gem_free_mmap_offset(obj);
    drm_gem_object_release(obj);

    /* This must occur last as it frees up the memory of the GEM object */
    psb_gtt_free_range(obj->dev, gtt);
}

int psb_gem_get_aperture(struct drm_device *dev, void *data,
                struct drm_file *file)
{
    return -EINVAL;
}

int psb_gem_dumb_map_gtt(struct drm_file *file, struct drm_device *dev,
             uint32_t handle, uint64_t *offset)
{
    int ret = 0;
    struct drm_gem_object *obj;

    if (!(dev->driver->driver_features & DRIVER_GEM))
        return -ENODEV;

    mutex_lock(&dev->struct_mutex);

    /* GEM does all our handle to object mapping */
    obj = drm_gem_object_lookup(dev, file, handle);
    if (obj == NULL) {
        ret = -ENOENT;
        goto unlock;
    }
    /* What validation is needed here ? */

    /* Make it mmapable */
    if (!obj->map_list.map) {
        ret = drm_gem_create_mmap_offset(obj);
        if (ret)
            goto out;
    }
    /* GEM should really work out the hash offsets for us */
    *offset = (u64)obj->map_list.hash.key << PAGE_SHIFT;
out:
    drm_gem_object_unreference(obj);
unlock:
    mutex_unlock(&dev->struct_mutex);
    return ret;
}

static int psb_gem_create(struct drm_file *file,
    struct drm_device *dev, uint64_t size, uint32_t *handlep)
{
    struct gtt_range *r;
    int ret;
    u32 handle;

    size = roundup(size, PAGE_SIZE);

    /* Allocate our object - for now a direct gtt range which is not
       stolen memory backed */
    r = psb_gtt_alloc_range(dev, size, "gem", 0);
    if (r == NULL) {
        dev_err(dev->dev, "no memory for %lld byte GEM object\n", size);
        return -ENOSPC;
    }
    /* Initialize the extra goodies GEM needs to do all the hard work */
    if (drm_gem_object_init(dev, &r->gem, size) != 0) {
        psb_gtt_free_range(dev, r);
        /* GEM doesn't give an error code so use -ENOMEM */
        dev_err(dev->dev, "GEM init failed for %lld\n", size);
        return -ENOMEM;
    }
    /* Limit the object to 32bit mappings */
    mapping_set_gfp_mask(r->gem.filp->f_mapping, GFP_KERNEL | __GFP_DMA32);
    /* Give the object a handle so we can carry it more easily */
    ret = drm_gem_handle_create(file, &r->gem, &handle);
    if (ret) {
        dev_err(dev->dev, "GEM handle failed for %p, %lld\n",
                            &r->gem, size);
        drm_gem_object_release(&r->gem);
        psb_gtt_free_range(dev, r);
        return ret;
    }
    /* We have the initial and handle reference but need only one now */
    drm_gem_object_unreference(&r->gem);
    *handlep = handle;
    return 0;
}

int psb_gem_dumb_create(struct drm_file *file, struct drm_device *dev,
            struct drm_mode_create_dumb *args)
{
    args->pitch = ALIGN(args->width * ((args->bpp + 7) / 8), 64);
    args->size = args->pitch * args->height;
    return psb_gem_create(file, dev, args->size, &args->handle);
}

int psb_gem_dumb_destroy(struct drm_file *file, struct drm_device *dev,
            uint32_t handle)
{
    /* No special work needed, drop the reference and see what falls out */
    return drm_gem_handle_delete(file, handle);
}

int psb_gem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
    struct drm_gem_object *obj;
    struct gtt_range *r;
    int ret;
    unsigned long pfn;
    pgoff_t page_offset;
    struct drm_device *dev;
    struct drm_psb_private *dev_priv;

    obj = vma->vm_private_data; /* GEM object */
    dev = obj->dev;
    dev_priv = dev->dev_private;

    r = container_of(obj, struct gtt_range, gem);   /* Get the gtt range */

    /* Make sure we don't parallel update on a fault, nor move or remove
       something from beneath our feet */
    mutex_lock(&dev->struct_mutex);

    /* For now the mmap pins the object and it stays pinned. As things
       stand that will do us no harm */
    if (r->mmapping == 0) {
        ret = psb_gtt_pin(r);
        if (ret < 0) {
            dev_err(dev->dev, "gma500: pin failed: %d\n", ret);
            goto fail;
        }
        r->mmapping = 1;
    }

    /* Page relative to the VMA start - we must calculate this ourselves
       because vmf->pgoff is the fake GEM offset */
    page_offset = ((unsigned long) vmf->virtual_address - vma->vm_start)
                >> PAGE_SHIFT;

    /* CPU view of the page, don't go via the GART for CPU writes */
    if (r->stolen)
        pfn = (dev_priv->stolen_base + r->offset) >> PAGE_SHIFT;
    else
        pfn = page_to_pfn(r->pages[page_offset]);
    ret = vm_insert_pfn(vma, (unsigned long)vmf->virtual_address, pfn);

fail:
    mutex_unlock(&dev->struct_mutex);
    switch (ret) {
    case 0:
    case -ERESTARTSYS:
    case -EINTR:
        return VM_FAULT_NOPAGE;
    case -ENOMEM:
        return VM_FAULT_OOM;
    default:
        return VM_FAULT_SIGBUS;
    }
}

static int psb_gem_create_stolen(struct drm_file *file, struct drm_device *dev,
                        int size, u32 *handle)
{
    struct gtt_range *gtt = psb_gtt_alloc_range(dev, size, "gem", 1);
    if (gtt == NULL)
        return -ENOMEM;
    if (drm_gem_private_object_init(dev, &gtt->gem, size) != 0)
        goto free_gtt;
    if (drm_gem_handle_create(file, &gtt->gem, handle) == 0)
        return 0;
free_gtt:
    psb_gtt_free_range(dev, gtt);
    return -ENOMEM;
}

/*
 *  GEM interfaces for our specific client
 */
int psb_gem_create_ioctl(struct drm_device *dev, void *data,
                    struct drm_file *file)
{
    struct drm_psb_gem_create *args = data;
    int ret;
    if (args->flags & GMA_GEM_CREATE_STOLEN) {
        ret = psb_gem_create_stolen(file, dev, args->size,
                            &args->handle);
        if (ret == 0)
            return 0;
        /* Fall throguh */
        args->flags &= ~GMA_GEM_CREATE_STOLEN;
    }
    return psb_gem_create(file, dev, args->size, &args->handle);
}

int psb_gem_mmap_ioctl(struct drm_device *dev, void *data,
                    struct drm_file *file)
{
    struct drm_psb_gem_mmap *args = data;
    return dev->driver->dumb_map_offset(file, dev,
                        args->handle, &args->offset);
}