Commit 04408952 authored by Thomas Zimmermann's avatar Thomas Zimmermann
Browse files

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



Implement DRM fbdev helpers for reading and writing framebuffer
memory with the respective fbdev functions. Removes duplicate
code.

v2:
	* rename fb_cfb_() to fb_io_() (Geert)

Signed-off-by: default avatarThomas Zimmermann <tzimmermann@suse.de>
Tested-by: default avatarSui Jingfeng <suijingfeng@loongson.cn>
Reviewed-by: default avatarJavier Martinez Canillas <javierm@redhat.com>
Acked-by: default avatarHelge Deller <deller@gmx.de>
Reviewed-by: default avatarSam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230428122452.4856-20-tzimmermann@suse.de
parent 6121cd9e

drivers/gpu/drm/drm_fb_helper.c

+4 −170
Original line number Diff line number Diff line
@@ -706,95 +706,6 @@ 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
@@ -808,21 +719,10 @@ 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
@@ -841,7 +741,7 @@ 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;
@@ -913,39 +813,6 @@ 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
@@ -959,43 +826,10 @@ 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_io_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
@@ -1014,7 +848,7 @@ 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_io_write(info, buf, count, ppos);

	if (ret <= 0)

		return ret;