/* SPDX-License-Identifier: GPL-2.0-only * *	Virtual memory framebuffer access for drawing routines * *	Copyright (C) 2025 Zsolt Kajtar (soci@c64.rulez.org) */ /* keeps track of a bit address in framebuffer memory */struct fb_address {	void *address;	int bits;}; /* initialize the bit address pointer to the beginning of the frame buffer */static inline struct fb_address fb_address_init(struct fb_info *p){	void *base = p->screen_buffer;	struct fb_address ptr; 	ptr.address = PTR_ALIGN_DOWN(base, BITS_PER_LONG / BITS_PER_BYTE);	ptr.bits = (base - ptr.address) * BITS_PER_BYTE;	return ptr;} /* framebuffer write access */static inline void fb_write_offset(unsigned long val, int offset, const struct fb_address *dst){	unsigned long *mem = dst->address; 	mem[offset] = val;} /* framebuffer read access */static inline unsigned long fb_read_offset(int offset, const struct fb_address *src){	unsigned long *mem = src->address; 	return mem[offset];}