udl_gem.c

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/*
 * Copyright (C) 2012 Red Hat
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License v2. See the file COPYING in the main directory of this archive for
 * more details.
 */

#include <drm/drmP.h>
#include "udl_drv.h"
#include <linux/shmem_fs.h>
#include <linux/dma-buf.h>

struct udl_gem_object *udl_gem_alloc_object(struct drm_device *dev,
                        size_t size)
{
    struct udl_gem_object *obj;

    obj = kzalloc(sizeof(*obj), GFP_KERNEL);
    if (obj == NULL)
        return NULL;

    if (drm_gem_object_init(dev, &obj->base, size) != 0) {
        kfree(obj);
        return NULL;
    }

    return obj;
}

static int
udl_gem_create(struct drm_file *file,
           struct drm_device *dev,
           uint64_t size,
           uint32_t *handle_p)
{
    struct udl_gem_object *obj;
    int ret;
    u32 handle;

    size = roundup(size, PAGE_SIZE);

    obj = udl_gem_alloc_object(dev, size);
    if (obj == NULL)
        return -ENOMEM;

    ret = drm_gem_handle_create(file, &obj->base, &handle);
    if (ret) {
        drm_gem_object_release(&obj->base);
        kfree(obj);
        return ret;
    }

    drm_gem_object_unreference(&obj->base);
    *handle_p = handle;
    return 0;
}

int udl_dumb_create(struct drm_file *file,
            struct drm_device *dev,
            struct drm_mode_create_dumb *args)
{
    args->pitch = args->width * ((args->bpp + 1) / 8);
    args->size = args->pitch * args->height;
    return udl_gem_create(file, dev,
                  args->size, &args->handle);
}

int udl_dumb_destroy(struct drm_file *file, struct drm_device *dev,
             uint32_t handle)
{
    return drm_gem_handle_delete(file, handle);
}

int udl_drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
{
    int ret;

    ret = drm_gem_mmap(filp, vma);
    if (ret)
        return ret;

    vma->vm_flags &= ~VM_PFNMAP;
    vma->vm_flags |= VM_MIXEDMAP;

    return ret;
}

int udl_gem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
    struct udl_gem_object *obj = to_udl_bo(vma->vm_private_data);
    struct page *page;
    unsigned int page_offset;
    int ret = 0;

    page_offset = ((unsigned long)vmf->virtual_address - vma->vm_start) >>
        PAGE_SHIFT;

    if (!obj->pages)
        return VM_FAULT_SIGBUS;

    page = obj->pages[page_offset];
    ret = vm_insert_page(vma, (unsigned long)vmf->virtual_address, page);
    switch (ret) {
    case -EAGAIN:
        set_need_resched();
    case 0:
    case -ERESTARTSYS:
        return VM_FAULT_NOPAGE;
    case -ENOMEM:
        return VM_FAULT_OOM;
    default:
        return VM_FAULT_SIGBUS;
    }
}

int udl_gem_init_object(struct drm_gem_object *obj)
{
    BUG();

    return 0;
}

static int udl_gem_get_pages(struct udl_gem_object *obj, gfp_t gfpmask)
{
    int page_count, i;
    struct page *page;
    struct inode *inode;
    struct address_space *mapping;

    if (obj->pages)
        return 0;

    page_count = obj->base.size / PAGE_SIZE;
    BUG_ON(obj->pages != NULL);
    obj->pages = drm_malloc_ab(page_count, sizeof(struct page *));
    if (obj->pages == NULL)
        return -ENOMEM;

    inode = obj->base.filp->f_path.dentry->d_inode;
    mapping = inode->i_mapping;
    gfpmask |= mapping_gfp_mask(mapping);

    for (i = 0; i < page_count; i++) {
        page = shmem_read_mapping_page_gfp(mapping, i, gfpmask);
        if (IS_ERR(page))
            goto err_pages;
        obj->pages[i] = page;
    }

    return 0;
err_pages:
    while (i--)
        page_cache_release(obj->pages[i]);
    drm_free_large(obj->pages);
    obj->pages = NULL;
    return PTR_ERR(page);
}

static void udl_gem_put_pages(struct udl_gem_object *obj)
{
    int page_count = obj->base.size / PAGE_SIZE;
    int i;

    if (obj->base.import_attach) {
        drm_free_large(obj->pages);
        obj->pages = NULL;
        return;
    }

    for (i = 0; i < page_count; i++)
        page_cache_release(obj->pages[i]);

    drm_free_large(obj->pages);
    obj->pages = NULL;
}

int udl_gem_vmap(struct udl_gem_object *obj)
{
    int page_count = obj->base.size / PAGE_SIZE;
    int ret;

    if (obj->base.import_attach) {
        obj->vmapping = dma_buf_vmap(obj->base.import_attach->dmabuf);
        if (!obj->vmapping)
            return -ENOMEM;
        return 0;
    }
        
    ret = udl_gem_get_pages(obj, GFP_KERNEL);
    if (ret)
        return ret;

    obj->vmapping = vmap(obj->pages, page_count, 0, PAGE_KERNEL);
    if (!obj->vmapping)
        return -ENOMEM;
    return 0;
}

void udl_gem_vunmap(struct udl_gem_object *obj)
{
    if (obj->base.import_attach) {
        dma_buf_vunmap(obj->base.import_attach->dmabuf, obj->vmapping);
        return;
    }

    if (obj->vmapping)
        vunmap(obj->vmapping);

    udl_gem_put_pages(obj);
}

void udl_gem_free_object(struct drm_gem_object *gem_obj)
{
    struct udl_gem_object *obj = to_udl_bo(gem_obj);

    if (obj->vmapping)
        udl_gem_vunmap(obj);

    if (gem_obj->import_attach)
        drm_prime_gem_destroy(gem_obj, obj->sg);

    if (obj->pages)
        udl_gem_put_pages(obj);

    if (gem_obj->map_list.map)
        drm_gem_free_mmap_offset(gem_obj);
}

/* the dumb interface doesn't work with the GEM straight MMAP
   interface, it expects to do MMAP on the drm fd, like normal */
int udl_gem_mmap(struct drm_file *file, struct drm_device *dev,
         uint32_t handle, uint64_t *offset)
{
    struct udl_gem_object *gobj;
    struct drm_gem_object *obj;
    int ret = 0;

    mutex_lock(&dev->struct_mutex);
    obj = drm_gem_object_lookup(dev, file, handle);
    if (obj == NULL) {
        ret = -ENOENT;
        goto unlock;
    }
    gobj = to_udl_bo(obj);

    ret = udl_gem_get_pages(gobj, GFP_KERNEL);
    if (ret)
        goto out;
    if (!gobj->base.map_list.map) {
        ret = drm_gem_create_mmap_offset(obj);
        if (ret)
            goto out;
    }

    *offset = (u64)gobj->base.map_list.hash.key << PAGE_SHIFT;

out:
    drm_gem_object_unreference(&gobj->base);
unlock:
    mutex_unlock(&dev->struct_mutex);
    return ret;
}

static int udl_prime_create(struct drm_device *dev,
                size_t size,
                struct sg_table *sg,
                struct udl_gem_object **obj_p)
{
    struct udl_gem_object *obj;
    int npages;

    npages = size / PAGE_SIZE;

    *obj_p = NULL;
    obj = udl_gem_alloc_object(dev, npages * PAGE_SIZE);
    if (!obj)
        return -ENOMEM;

    obj->sg = sg;
    obj->pages = drm_malloc_ab(npages, sizeof(struct page *));
    if (obj->pages == NULL) {
        DRM_ERROR("obj pages is NULL %d\n", npages);
        return -ENOMEM;
    }

    drm_prime_sg_to_page_addr_arrays(sg, obj->pages, NULL, npages);

    *obj_p = obj;
    return 0;
}

struct drm_gem_object *udl_gem_prime_import(struct drm_device *dev,
                struct dma_buf *dma_buf)
{
    struct dma_buf_attachment *attach;
    struct sg_table *sg;
    struct udl_gem_object *uobj;
    int ret;

    /* need to attach */
    attach = dma_buf_attach(dma_buf, dev->dev);
    if (IS_ERR(attach))
        return ERR_CAST(attach);

    sg = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
    if (IS_ERR(sg)) {
        ret = PTR_ERR(sg);
        goto fail_detach;
    }

    ret = udl_prime_create(dev, dma_buf->size, sg, &uobj);
    if (ret) {
        goto fail_unmap;
    }

    uobj->base.import_attach = attach;

    return &uobj->base;

fail_unmap:
    dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
fail_detach:
    dma_buf_detach(dma_buf, attach);
    return ERR_PTR(ret);
}