[6/6] drm/fb-helper: Use fb_{cfb,sys}_{read, write}()

Sui Jingfeng 15330273260 at 189.cn
Wed Apr 26 10:26:28 UTC 2023


Tested-by: Sui Jingfeng <suijingfeng at loongson.cn>

On 2023/4/25 22:28, Thomas Zimmermann wrote:
> Implement DRM fbdev helpers for reading and writing framebuffer
> memory with the respective fbdev functions. Removes duplicate
> code.
>
> Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
> Reviewed-by: Javier Martinez Canillas <javierm at redhat.com>
> ---
>   drivers/gpu/drm/drm_fb_helper.c | 174 +-------------------------------
>   1 file changed, 4 insertions(+), 170 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
> index 6bb1b8b27d7a..e11858470fa7 100644
> --- a/drivers/gpu/drm/drm_fb_helper.c
> +++ b/drivers/gpu/drm/drm_fb_helper.c
> @@ -714,95 +714,6 @@ void drm_fb_helper_deferred_io(struct fb_info *info, struct list_head *pagerefli
>   }
>   EXPORT_SYMBOL(drm_fb_helper_deferred_io);
>   
> -typedef ssize_t (*drm_fb_helper_read_screen)(struct fb_info *info, char __user *buf,
> -					     size_t count, loff_t pos);
> -
> -static ssize_t __drm_fb_helper_read(struct fb_info *info, char __user *buf, size_t count,
> -				    loff_t *ppos, drm_fb_helper_read_screen read_screen)
> -{
> -	loff_t pos = *ppos;
> -	size_t total_size;
> -	ssize_t ret;
> -
> -	if (info->screen_size)
> -		total_size = info->screen_size;
> -	else
> -		total_size = info->fix.smem_len;
> -
> -	if (pos >= total_size)
> -		return 0;
> -	if (count >= total_size)
> -		count = total_size;
> -	if (total_size - count < pos)
> -		count = total_size - pos;
> -
> -	if (info->fbops->fb_sync)
> -		info->fbops->fb_sync(info);
> -
> -	ret = read_screen(info, buf, count, pos);
> -	if (ret > 0)
> -		*ppos += ret;
> -
> -	return ret;
> -}
> -
> -typedef ssize_t (*drm_fb_helper_write_screen)(struct fb_info *info, const char __user *buf,
> -					      size_t count, loff_t pos);
> -
> -static ssize_t __drm_fb_helper_write(struct fb_info *info, const char __user *buf, size_t count,
> -				     loff_t *ppos, drm_fb_helper_write_screen write_screen)
> -{
> -	loff_t pos = *ppos;
> -	size_t total_size;
> -	ssize_t ret;
> -	int err = 0;
> -
> -	if (info->screen_size)
> -		total_size = info->screen_size;
> -	else
> -		total_size = info->fix.smem_len;
> -
> -	if (pos > total_size)
> -		return -EFBIG;
> -	if (count > total_size) {
> -		err = -EFBIG;
> -		count = total_size;
> -	}
> -	if (total_size - count < pos) {
> -		if (!err)
> -			err = -ENOSPC;
> -		count = total_size - pos;
> -	}
> -
> -	if (info->fbops->fb_sync)
> -		info->fbops->fb_sync(info);
> -
> -	/*
> -	 * Copy to framebuffer even if we already logged an error. Emulates
> -	 * the behavior of the original fbdev implementation.
> -	 */
> -	ret = write_screen(info, buf, count, pos);
> -	if (ret < 0)
> -		return ret; /* return last error, if any */
> -	else if (!ret)
> -		return err; /* return previous error, if any */
> -
> -	*ppos += ret;
> -
> -	return ret;
> -}
> -
> -static ssize_t drm_fb_helper_read_screen_buffer(struct fb_info *info, char __user *buf,
> -						size_t count, loff_t pos)
> -{
> -	const char *src = info->screen_buffer + pos;
> -
> -	if (copy_to_user(buf, src, count))
> -		return -EFAULT;
> -
> -	return count;
> -}
> -
>   /**
>    * drm_fb_helper_sys_read - Implements struct &fb_ops.fb_read for system memory
>    * @info: fb_info struct pointer
> @@ -816,21 +727,10 @@ static ssize_t drm_fb_helper_read_screen_buffer(struct fb_info *info, char __use
>   ssize_t drm_fb_helper_sys_read(struct fb_info *info, char __user *buf,
>   			       size_t count, loff_t *ppos)
>   {
> -	return __drm_fb_helper_read(info, buf, count, ppos, drm_fb_helper_read_screen_buffer);
> +	return fb_sys_read(info, buf, count, ppos);
>   }
>   EXPORT_SYMBOL(drm_fb_helper_sys_read);
>   
> -static ssize_t drm_fb_helper_write_screen_buffer(struct fb_info *info, const char __user *buf,
> -						 size_t count, loff_t pos)
> -{
> -	char *dst = info->screen_buffer + pos;
> -
> -	if (copy_from_user(dst, buf, count))
> -		return -EFAULT;
> -
> -	return count;
> -}
> -
>   /**
>    * drm_fb_helper_sys_write - Implements struct &fb_ops.fb_write for system memory
>    * @info: fb_info struct pointer
> @@ -849,7 +749,7 @@ ssize_t drm_fb_helper_sys_write(struct fb_info *info, const char __user *buf,
>   	ssize_t ret;
>   	struct drm_rect damage_area;
>   
> -	ret = __drm_fb_helper_write(info, buf, count, ppos, drm_fb_helper_write_screen_buffer);
> +	ret = fb_sys_write(info, buf, count, ppos);
>   	if (ret <= 0)
>   		return ret;
>   
> @@ -921,39 +821,6 @@ void drm_fb_helper_sys_imageblit(struct fb_info *info,
>   }
>   EXPORT_SYMBOL(drm_fb_helper_sys_imageblit);
>   
> -static ssize_t fb_read_screen_base(struct fb_info *info, char __user *buf, size_t count,
> -				   loff_t pos)
> -{
> -	const char __iomem *src = info->screen_base + pos;
> -	size_t alloc_size = min_t(size_t, count, PAGE_SIZE);
> -	ssize_t ret = 0;
> -	int err = 0;
> -	char *tmp;
> -
> -	tmp = kmalloc(alloc_size, GFP_KERNEL);
> -	if (!tmp)
> -		return -ENOMEM;
> -
> -	while (count) {
> -		size_t c = min_t(size_t, count, alloc_size);
> -
> -		memcpy_fromio(tmp, src, c);
> -		if (copy_to_user(buf, tmp, c)) {
> -			err = -EFAULT;
> -			break;
> -		}
> -
> -		src += c;
> -		buf += c;
> -		ret += c;
> -		count -= c;
> -	}
> -
> -	kfree(tmp);
> -
> -	return ret ? ret : err;
> -}
> -
>   /**
>    * drm_fb_helper_cfb_read - Implements struct &fb_ops.fb_read for I/O memory
>    * @info: fb_info struct pointer
> @@ -967,43 +834,10 @@ static ssize_t fb_read_screen_base(struct fb_info *info, char __user *buf, size_
>   ssize_t drm_fb_helper_cfb_read(struct fb_info *info, char __user *buf,
>   			       size_t count, loff_t *ppos)
>   {
> -	return __drm_fb_helper_read(info, buf, count, ppos, fb_read_screen_base);
> +	return fb_cfb_read(info, buf, count, ppos);
>   }
>   EXPORT_SYMBOL(drm_fb_helper_cfb_read);
>   
> -static ssize_t fb_write_screen_base(struct fb_info *info, const char __user *buf, size_t count,
> -				    loff_t pos)
> -{
> -	char __iomem *dst = info->screen_base + pos;
> -	size_t alloc_size = min_t(size_t, count, PAGE_SIZE);
> -	ssize_t ret = 0;
> -	int err = 0;
> -	u8 *tmp;
> -
> -	tmp = kmalloc(alloc_size, GFP_KERNEL);
> -	if (!tmp)
> -		return -ENOMEM;
> -
> -	while (count) {
> -		size_t c = min_t(size_t, count, alloc_size);
> -
> -		if (copy_from_user(tmp, buf, c)) {
> -			err = -EFAULT;
> -			break;
> -		}
> -		memcpy_toio(dst, tmp, c);
> -
> -		dst += c;
> -		buf += c;
> -		ret += c;
> -		count -= c;
> -	}
> -
> -	kfree(tmp);
> -
> -	return ret ? ret : err;
> -}
> -
>   /**
>    * drm_fb_helper_cfb_write - Implements struct &fb_ops.fb_write for I/O memory
>    * @info: fb_info struct pointer
> @@ -1022,7 +856,7 @@ ssize_t drm_fb_helper_cfb_write(struct fb_info *info, const char __user *buf,
>   	ssize_t ret;
>   	struct drm_rect damage_area;
>   
> -	ret = __drm_fb_helper_write(info, buf, count, ppos, fb_write_screen_base);
> +	ret = fb_cfb_write(info, buf, count, ppos);
>   	if (ret <= 0)
>   		return ret;
>   


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