Commit 33253d9e authored by Thomas Zimmermann's avatar Thomas Zimmermann
Browse files

fbdev: Move default fb_mmap code into helper function 



Move the default fb_mmap code for I/O address spaces into the helper
function fb_io_mmap(). The helper can either be called via struct
fb_ops.fb_mmap or as the default if no fb_mmap has been set. Also
set the new helper in __FB_DEFAULT_IOMEM_OPS_MMAP.

In the mid-term, fb_io_mmap() is supposed to become optional. Fbdev
drivers will initialize their struct fb_ops.fb_mmap to the helper
and select a corresponding Kconfig token. The helper can then be made
optional at compile time.

Signed-off-by: default avatarThomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: default avatarJavier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231127131655.4020-31-tzimmermann@suse.de
parent 76f92201

drivers/video/fbdev/core/fb_chrdev.c

+6 −30
Original line number Diff line number Diff line
@@ -314,20 +314,16 @@ static long fb_compat_ioctl(struct file *file, unsigned int cmd, 
static int fb_mmap(struct file *file, struct vm_area_struct *vma)

{

	struct fb_info *info = file_fb_info(file);

	unsigned long mmio_pgoff;

	unsigned long start;

	u32 len;

	int res;



	if (!info)

		return -ENODEV;



	mutex_lock(&info->mm_lock);



	if (info->fbops->fb_mmap) {

		int res;



		res = info->fbops->fb_mmap(info, vma);

		mutex_unlock(&info->mm_lock);

		return res;

#if IS_ENABLED(CONFIG_FB_DEFERRED_IO)

	} else if (info->fbdefio) {

		/*
@@ -335,35 +331,15 @@ static int fb_mmap(struct file *file, struct vm_area_struct *vma) 
		 * minimum, point struct fb_ops.fb_mmap to fb_deferred_io_mmap().

		 */

		dev_warn_once(info->dev, "fbdev mmap not set up for deferred I/O.\n");

		mutex_unlock(&info->mm_lock);

		return -ENODEV;

		res = -ENODEV;

#endif

	} else {

		res = fb_io_mmap(info, vma);

	}



	/*

	 * Ugh. This can be either the frame buffer mapping, or

	 * if pgoff points past it, the mmio mapping.

	 */

	start = info->fix.smem_start;

	len = info->fix.smem_len;

	mmio_pgoff = PAGE_ALIGN((start & ~PAGE_MASK) + len) >> PAGE_SHIFT;

	if (vma->vm_pgoff >= mmio_pgoff) {

		if (info->var.accel_flags) {

	mutex_unlock(&info->mm_lock);

			return -EINVAL;

		}



		vma->vm_pgoff -= mmio_pgoff;

		start = info->fix.mmio_start;

		len = info->fix.mmio_len;

	}

	mutex_unlock(&info->mm_lock);



	vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);

	vma->vm_page_prot = pgprot_framebuffer(vma->vm_page_prot, vma->vm_start,

					       vma->vm_end, start);



	return vm_iomap_memory(vma, start, len);

	return res;

}



static int fb_open(struct inode *inode, struct file *file)

drivers/video/fbdev/core/fb_io_fops.c

+27 −0
Original line number Diff line number Diff line
@@ -132,5 +132,32 @@ ssize_t fb_io_write(struct fb_info *info, const char __user *buf, size_t count, 
}

EXPORT_SYMBOL(fb_io_write);



int fb_io_mmap(struct fb_info *info, struct vm_area_struct *vma)

{

	unsigned long start = info->fix.smem_start;

	u32 len = info->fix.smem_len;

	unsigned long mmio_pgoff = PAGE_ALIGN((start & ~PAGE_MASK) + len) >> PAGE_SHIFT;



	/*

	 * This can be either the framebuffer mapping, or if pgoff points

	 * past it, the mmio mapping.

	 */

	if (vma->vm_pgoff >= mmio_pgoff) {

		if (info->var.accel_flags)

			return -EINVAL;



		vma->vm_pgoff -= mmio_pgoff;

		start = info->fix.mmio_start;

		len = info->fix.mmio_len;

	}



	vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);

	vma->vm_page_prot = pgprot_framebuffer(vma->vm_page_prot, vma->vm_start,

					       vma->vm_end, start);



	return vm_iomap_memory(vma, start, len);

}

EXPORT_SYMBOL(fb_io_mmap);



MODULE_DESCRIPTION("Fbdev helpers for framebuffers in I/O memory");

MODULE_LICENSE("GPL");

include/linux/fb.h

+2 −1
Original line number Diff line number Diff line
@@ -536,6 +536,7 @@ extern ssize_t fb_io_read(struct fb_info *info, char __user *buf, 
			  size_t count, loff_t *ppos);

extern ssize_t fb_io_write(struct fb_info *info, const char __user *buf,

			   size_t count, loff_t *ppos);

int fb_io_mmap(struct fb_info *info, struct vm_area_struct *vma);



#define __FB_DEFAULT_IOMEM_OPS_RDWR \

	.fb_read	= fb_io_read, \
@@ -547,7 +548,7 @@ extern ssize_t fb_io_write(struct fb_info *info, const char __user *buf, 
	.fb_imageblit	= cfb_imageblit



#define __FB_DEFAULT_IOMEM_OPS_MMAP \

	.fb_mmap	= NULL /* default implementation */

	.fb_mmap	= fb_io_mmap



#define FB_DEFAULT_IOMEM_OPS \

	__FB_DEFAULT_IOMEM_OPS_RDWR, \