/* SPDX-License-Identifier: GPL-2.0-or-later */ /* * OpenRISC Linux * * Linux architectural port borrowing liberally from similar works of * others. All original copyrights apply as per the original source * declaration. * * OpenRISC implementation: * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com> * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se> * et al. */ #ifndef __ASM_OPENRISC_FIXMAP_H #define __ASM_OPENRISC_FIXMAP_H /* Why exactly do we need 2 empty pages between the top of the fixed * addresses and the top of virtual memory? Something is using that * memory space but not sure what right now... If you find it, leave * a comment here. */ #define FIXADDR_TOP ((unsigned long) (-2*PAGE_SIZE)) #include <linux/kernel.h> #include <linux/bug.h> #include <asm/page.h> /* * On OpenRISC we use these special fixed_addresses for doing ioremap * early in the boot process before memory initialization is complete. * This is used, in particular, by the early serial console code. * * It's not really 'fixmap', per se, but fits loosely into the same * paradigm. */ enum fixed_addresses { /* * FIX_IOREMAP entries are useful for mapping physical address * space before ioremap() is useable, e.g. really early in boot * before kmalloc() is working. */ #define FIX_N_IOREMAPS 32 FIX_IOREMAP_BEGIN, FIX_IOREMAP_END = FIX_IOREMAP_BEGIN + FIX_N_IOREMAPS - 1, __end_of_fixed_addresses }; #define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT) /* FIXADDR_BOTTOM might be a better name here... */ #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) #define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT)) #define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT) /* * 'index to address' translation. If anyone tries to use the idx * directly without tranlation, we catch the bug with a NULL-deference * kernel oops. Illegal ranges of incoming indices are caught too. */ static __always_inline unsigned long fix_to_virt(const unsigned int idx) { /* * this branch gets completely eliminated after inlining, * except when someone tries to use fixaddr indices in an * illegal way. (such as mixing up address types or using * out-of-range indices). * * If it doesn't get removed, the linker will complain * loudly with a reasonably clear error message.. */ if (idx >= __end_of_fixed_addresses) BUG(); return __fix_to_virt(idx); } static inline unsigned long virt_to_fix(const unsigned long vaddr) { BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START); return __virt_to_fix(vaddr); } #endif