projects / mirror_ubuntu-kernels.git / blame
| Commit | Line | Data |
|---|---|---|
| 2874c5fd | 1 | /* SPDX-License-Identifier: GPL-2.0-or-later */ |
| 61e85e36 JB |
2 | /* |
| 3 | * OpenRISC Linux | |
| 4 | * | |
| 5 | * Linux architectural port borrowing liberally from similar works of | |
| 6 | * others. All original copyrights apply as per the original source | |
| 7 | * declaration. | |
| 8 | * | |
| 9 | * OpenRISC implementation: | |
| 10 | * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com> | |
| 11 | * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se> | |
| 12 | * et al. | |
| 61e85e36 JB |
13 | */ |
| 14 | ||
| 15 | #ifndef __ASM_OPENRISC_FIXMAP_H | |
| 16 | #define __ASM_OPENRISC_FIXMAP_H | |
| 17 | ||
| 18 | /* Why exactly do we need 2 empty pages between the top of the fixed | |
| 19 | * addresses and the top of virtual memory? Something is using that | |
| 20 | * memory space but not sure what right now... If you find it, leave | |
| 21 | * a comment here. | |
| 22 | */ | |
| 23 | #define FIXADDR_TOP ((unsigned long) (-2*PAGE_SIZE)) | |
| 24 | ||
| 25 | #include <linux/kernel.h> | |
| e687448c | 26 | #include <linux/bug.h> |
| 61e85e36 JB |
27 | #include <asm/page.h> |
| 28 | ||
| 29 | /* | |
| 30 | * On OpenRISC we use these special fixed_addresses for doing ioremap | |
| 31 | * early in the boot process before memory initialization is complete. | |
| 32 | * This is used, in particular, by the early serial console code. | |
| 33 | * | |
| 34 | * It's not really 'fixmap', per se, but fits loosely into the same | |
| 35 | * paradigm. | |
| 36 | */ | |
| 37 | enum fixed_addresses { | |
| 38 | /* | |
| 39 | * FIX_IOREMAP entries are useful for mapping physical address | |
| 40 | * space before ioremap() is useable, e.g. really early in boot | |
| 41 | * before kmalloc() is working. | |
| 42 | */ | |
| 43 | #define FIX_N_IOREMAPS 32 | |
| 44 | FIX_IOREMAP_BEGIN, | |
| 45 | FIX_IOREMAP_END = FIX_IOREMAP_BEGIN + FIX_N_IOREMAPS - 1, | |
| 46 | __end_of_fixed_addresses | |
| 47 | }; | |
| 48 | ||
| 49 | #define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT) | |
| 50 | /* FIXADDR_BOTTOM might be a better name here... */ | |
| 51 | #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) | |
| 52 | ||
| 53 | #define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT)) | |
| 54 | #define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT) | |
| 55 | ||
| 56 | /* | |
| 57 | * 'index to address' translation. If anyone tries to use the idx | |
| 58 | * directly without tranlation, we catch the bug with a NULL-deference | |
| 59 | * kernel oops. Illegal ranges of incoming indices are caught too. | |
| 60 | */ | |
| 61 | static __always_inline unsigned long fix_to_virt(const unsigned int idx) | |
| 62 | { | |
| 63 | /* | |
| 64 | * this branch gets completely eliminated after inlining, | |
| 65 | * except when someone tries to use fixaddr indices in an | |
| 66 | * illegal way. (such as mixing up address types or using | |
| 67 | * out-of-range indices). | |
| 68 | * | |
| 69 | * If it doesn't get removed, the linker will complain | |
| 70 | * loudly with a reasonably clear error message.. | |
| 71 | */ | |
| 72 | if (idx >= __end_of_fixed_addresses) | |
| 73 | BUG(); | |
| 74 | ||
| 75 | return __fix_to_virt(idx); | |
| 76 | } | |
| 77 | ||
| 78 | static inline unsigned long virt_to_fix(const unsigned long vaddr) | |
| 79 | { | |
| 80 | BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START); | |
| 81 | return __virt_to_fix(vaddr); | |
| 82 | } | |
| 83 | ||
| 84 | #endif |