On Mon, Aug 28, 2017 at 07:17:45PM +0200, Noralf Trønnes wrote:
> Add drm_fbdev_cma_dev_unplug() and use the drm_fb_helper device unplug
> support. Pin driver module on fb_open().
> 
> Cc: Laurent Pinchart <laurent.pinch...@ideasonboard.com>
> Signed-off-by: Noralf Trønnes <nor...@tronnes.org>
> ---
>  drivers/gpu/drm/drm_fb_cma_helper.c | 139 
> +++++++++++++++++-------------------
>  include/drm/drm_fb_cma_helper.h     |   1 +
>  2 files changed, 68 insertions(+), 72 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_fb_cma_helper.c 
> b/drivers/gpu/drm/drm_fb_cma_helper.c
> index f2ee883..2b044be 100644
> --- a/drivers/gpu/drm/drm_fb_cma_helper.c
> +++ b/drivers/gpu/drm/drm_fb_cma_helper.c
> @@ -25,8 +25,6 @@
>  #include <drm/drm_fb_cma_helper.h>
>  #include <linux/module.h>
>  
> -#define DEFAULT_FBDEFIO_DELAY_MS 50
> -
>  struct drm_fbdev_cma {
>       struct drm_fb_helper    fb_helper;
>       const struct drm_framebuffer_funcs *fb_funcs;
> @@ -238,6 +236,34 @@ int drm_fb_cma_debugfs_show(struct seq_file *m, void 
> *arg)
>  EXPORT_SYMBOL_GPL(drm_fb_cma_debugfs_show);
>  #endif
>  
> +static int drm_fbdev_cma_fb_open(struct fb_info *info, int user)
> +{
> +     struct drm_fb_helper *fb_helper = info->par;
> +     struct drm_device *dev = fb_helper->dev;
> +
> +     /*
> +      * The fb_ops definition resides in this library, meaning fb_open()
> +      * will take a ref on the library instead of the driver. Make sure the
> +      * driver module is pinned. Skip fbcon (user==0) since it can detach
> +      * itself on unregister_framebuffer().
> +      */
> +     if (user && !try_module_get(dev->driver->fops->owner))
> +             return -ENODEV;

I thought we've fixed this by redoing the fb_ops as a macro? Maybe tinydrm
isn't fixed yet, but then we need to fix up tinydrm. This here otoh kinda
smells a bit like a hack ...

If we need it, then I'd vote to put it into the fbdev helpers, not the cma
specific parts.

> +
> +     return 0;
> +}
> +
> +static int drm_fbdev_cma_fb_release(struct fb_info *info, int user)
> +{
> +     struct drm_fb_helper *fb_helper = info->par;
> +     struct drm_device *dev = fb_helper->dev;
> +
> +     if (user)
> +             module_put(dev->driver->fops->owner);
> +
> +     return 0;
> +}
> +
>  static int drm_fb_cma_mmap(struct fb_info *info, struct vm_area_struct *vma)
>  {
>       return dma_mmap_writecombine(info->device, vma, info->screen_base,
> @@ -247,10 +273,13 @@ static int drm_fb_cma_mmap(struct fb_info *info, struct 
> vm_area_struct *vma)
>  static struct fb_ops drm_fbdev_cma_ops = {
>       .owner          = THIS_MODULE,
>       DRM_FB_HELPER_DEFAULT_OPS,
> +     .fb_open        = drm_fbdev_cma_fb_open,
> +     .fb_release     = drm_fbdev_cma_fb_release,
>       .fb_fillrect    = drm_fb_helper_sys_fillrect,
>       .fb_copyarea    = drm_fb_helper_sys_copyarea,
>       .fb_imageblit   = drm_fb_helper_sys_imageblit,
>       .fb_mmap        = drm_fb_cma_mmap,
> +     .fb_destroy     = drm_fb_helper_fb_destroy,
>  };
>  
>  static int drm_fbdev_cma_deferred_io_mmap(struct fb_info *info,
> @@ -262,52 +291,26 @@ static int drm_fbdev_cma_deferred_io_mmap(struct 
> fb_info *info,
>       return 0;
>  }
>  
> -static int drm_fbdev_cma_defio_init(struct fb_info *fbi,
> +static int drm_fbdev_cma_defio_init(struct drm_fb_helper *helper,
>                                   struct drm_gem_cma_object *cma_obj)
>  {
> -     struct fb_deferred_io *fbdefio;
> -     struct fb_ops *fbops;
> +     struct fb_info *fbi = helper->fbdev;
> +     int ret;
>  
> -     /*
> -      * Per device structures are needed because:
> -      * fbops: fb_deferred_io_cleanup() clears fbops.fb_mmap
> -      * fbdefio: individual delays
> -      */
> -     fbdefio = kzalloc(sizeof(*fbdefio), GFP_KERNEL);
> -     fbops = kzalloc(sizeof(*fbops), GFP_KERNEL);
> -     if (!fbdefio || !fbops) {
> -             kfree(fbdefio);
> -             kfree(fbops);
> -             return -ENOMEM;
> -     }
> +     ret = drm_fb_helper_defio_init(helper);
> +     if (ret)
> +             return ret;
>  
>       /* can't be offset from vaddr since dirty() uses cma_obj */
>       fbi->screen_buffer = cma_obj->vaddr;
>       /* fb_deferred_io_fault() needs a physical address */
>       fbi->fix.smem_start = page_to_phys(virt_to_page(fbi->screen_buffer));
>  
> -     *fbops = *fbi->fbops;
> -     fbi->fbops = fbops;
> -
> -     fbdefio->delay = msecs_to_jiffies(DEFAULT_FBDEFIO_DELAY_MS);
> -     fbdefio->deferred_io = drm_fb_helper_deferred_io;
> -     fbi->fbdefio = fbdefio;
> -     fb_deferred_io_init(fbi);
>       fbi->fbops->fb_mmap = drm_fbdev_cma_deferred_io_mmap;
>  
>       return 0;
>  }
>  
> -static void drm_fbdev_cma_defio_fini(struct fb_info *fbi)
> -{
> -     if (!fbi->fbdefio)
> -             return;
> -
> -     fb_deferred_io_cleanup(fbi);
> -     kfree(fbi->fbdefio);
> -     kfree(fbi->fbops);
> -}
> -

Above changes look like unrelated cleanup? Should be a separate patch I
think.

>  static int
>  drm_fbdev_cma_create(struct drm_fb_helper *helper,
>       struct drm_fb_helper_surface_size *sizes)
> @@ -365,7 +368,7 @@ drm_fbdev_cma_create(struct drm_fb_helper *helper,
>       fbi->fix.smem_len = size;
>  
>       if (fbdev_cma->fb_funcs->dirty) {
> -             ret = drm_fbdev_cma_defio_init(fbi, obj);
> +             ret = drm_fbdev_cma_defio_init(helper, obj);
>               if (ret)
>                       goto err_cma_destroy;
>       }
> @@ -399,7 +402,6 @@ struct drm_fbdev_cma 
> *drm_fbdev_cma_init_with_funcs(struct drm_device *dev,
>       const struct drm_framebuffer_funcs *funcs)
>  {
>       struct drm_fbdev_cma *fbdev_cma;
> -     struct drm_fb_helper *helper;
>       int ret;
>  
>       fbdev_cma = kzalloc(sizeof(*fbdev_cma), GFP_KERNEL);
> @@ -409,37 +411,15 @@ struct drm_fbdev_cma 
> *drm_fbdev_cma_init_with_funcs(struct drm_device *dev,
>       }
>       fbdev_cma->fb_funcs = funcs;
>  
> -     helper = &fbdev_cma->fb_helper;
> -
> -     drm_fb_helper_prepare(dev, helper, &drm_fb_cma_helper_funcs);
> -
> -     ret = drm_fb_helper_init(dev, helper, max_conn_count);
> -     if (ret < 0) {
> -             dev_err(dev->dev, "Failed to initialize drm fb helper.\n");
> -             goto err_free;
> -     }
> -
> -     ret = drm_fb_helper_single_add_all_connectors(helper);
> -     if (ret < 0) {
> -             dev_err(dev->dev, "Failed to add connectors.\n");
> -             goto err_drm_fb_helper_fini;
> -
> -     }
> -
> -     ret = drm_fb_helper_initial_config(helper, preferred_bpp);
> -     if (ret < 0) {
> -             dev_err(dev->dev, "Failed to set initial hw configuration.\n");
> -             goto err_drm_fb_helper_fini;
> +     ret = drm_fb_helper_simple_init(dev, &fbdev_cma->fb_helper,
> +                                     preferred_bpp, max_conn_count,
> +                                     &drm_fb_cma_helper_funcs);

Yeah the conversion to simple* should be split out I think. But then I
thought more of this will be unified with the overall fbdev helpers?

> +     if (ret) {
> +             kfree(fbdev_cma);
> +             return ERR_PTR(ret);
>       }
>  
>       return fbdev_cma;
> -
> -err_drm_fb_helper_fini:
> -     drm_fb_helper_fini(helper);
> -err_free:
> -     kfree(fbdev_cma);
> -
> -     return ERR_PTR(ret);
>  }
>  EXPORT_SYMBOL_GPL(drm_fbdev_cma_init_with_funcs);
>  
> @@ -468,17 +448,15 @@ EXPORT_SYMBOL_GPL(drm_fbdev_cma_init);
>  /**
>   * drm_fbdev_cma_fini() - Free drm_fbdev_cma struct
>   * @fbdev_cma: The drm_fbdev_cma struct
> + *
> + * This function calls drm_fb_helper_simple_fini() and frees @fbdev_cma.
> + *
> + * Don't use this function together with drm_fbdev_cma_dev_unplug().
>   */
>  void drm_fbdev_cma_fini(struct drm_fbdev_cma *fbdev_cma)
>  {
> -     drm_fb_helper_unregister_fbi(&fbdev_cma->fb_helper);
> -     if (fbdev_cma->fb_helper.fbdev)
> -             drm_fbdev_cma_defio_fini(fbdev_cma->fb_helper.fbdev);
> -
> -     if (fbdev_cma->fb_helper.fb)
> -             drm_framebuffer_remove(fbdev_cma->fb_helper.fb);
> -
> -     drm_fb_helper_fini(&fbdev_cma->fb_helper);
> +     if (fbdev_cma)
> +             drm_fb_helper_simple_fini(&fbdev_cma->fb_helper);
>       kfree(fbdev_cma);
>  }
>  EXPORT_SYMBOL_GPL(drm_fbdev_cma_fini);
> @@ -542,3 +520,20 @@ void drm_fbdev_cma_set_suspend_unlocked(struct 
> drm_fbdev_cma *fbdev_cma,
>                                                  state);
>  }
>  EXPORT_SYMBOL(drm_fbdev_cma_set_suspend_unlocked);
> +
> +/**
> + * drm_fbdev_cma_dev_unplug - wrapper around drm_fb_helper_dev_unplug
> + * @fbdev_cma: The drm_fbdev_cma struct, may be NULL
> + *
> + * This unplugs the fbdev emulation for a hotpluggable DRM device. See
> + * drm_fb_helper_dev_unplug() for details.
> + *
> + * Drivers must call drm_mode_config_cleanup() and free @fbdev_cma in their
> + * &drm_driver->release callback.
> + */
> +void drm_fbdev_cma_dev_unplug(struct drm_fbdev_cma *fbdev_cma)
> +{
> +     if (fbdev_cma)
> +             drm_fb_helper_dev_unplug(&fbdev_cma->fb_helper);
> +}

I thought we're trying to phase out the cma helpers, why do we need a
wrapper for a wrapper?

> +EXPORT_SYMBOL(drm_fbdev_cma_dev_unplug);
> diff --git a/include/drm/drm_fb_cma_helper.h b/include/drm/drm_fb_cma_helper.h
> index a323781..a6aafae 100644
> --- a/include/drm/drm_fb_cma_helper.h
> +++ b/include/drm/drm_fb_cma_helper.h
> @@ -27,6 +27,7 @@ void drm_fbdev_cma_hotplug_event(struct drm_fbdev_cma 
> *fbdev_cma);
>  void drm_fbdev_cma_set_suspend(struct drm_fbdev_cma *fbdev_cma, bool state);
>  void drm_fbdev_cma_set_suspend_unlocked(struct drm_fbdev_cma *fbdev_cma,
>                                       bool state);
> +void drm_fbdev_cma_dev_unplug(struct drm_fbdev_cma *fbdev_cma);
>  
>  void drm_fb_cma_destroy(struct drm_framebuffer *fb);
>  int drm_fb_cma_create_handle(struct drm_framebuffer *fb,
> -- 
> 2.7.4
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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