1/* 2 * Copyright (C) 2004-2006 Atmel Corporation 3 * 4 * ASID handling taken from SH implementation. 5 * Copyright (C) 1999 Niibe Yutaka 6 * Copyright (C) 2003 Paul Mundt 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 */ 12#ifndef __ASM_AVR32_MMU_CONTEXT_H 13#define __ASM_AVR32_MMU_CONTEXT_H 14 15#include <asm/tlbflush.h> 16#include <asm/sysreg.h> 17#include <asm-generic/mm_hooks.h> 18 19/* 20 * The MMU "context" consists of two things: 21 * (a) TLB cache version 22 * (b) ASID (Address Space IDentifier) 23 */ 24#define MMU_CONTEXT_ASID_MASK 0x000000ff 25#define MMU_CONTEXT_VERSION_MASK 0xffffff00 26#define MMU_CONTEXT_FIRST_VERSION 0x00000100 27#define NO_CONTEXT 0 28 29#define MMU_NO_ASID 0x100 30 31/* Virtual Page Number mask */ 32#define MMU_VPN_MASK 0xfffff000 33 34/* Cache of MMU context last used */ 35extern unsigned long mmu_context_cache; 36 37/* 38 * Get MMU context if needed 39 */ 40static inline void 41get_mmu_context(struct mm_struct *mm) 42{ 43 unsigned long mc = mmu_context_cache; 44 45 if (((mm->context ^ mc) & MMU_CONTEXT_VERSION_MASK) == 0) 46 /* It's up to date, do nothing */ 47 return; 48 49 /* It's old, we need to get new context with new version */ 50 mc = ++mmu_context_cache; 51 if (!(mc & MMU_CONTEXT_ASID_MASK)) { 52 /* 53 * We have exhausted all ASIDs of this version. 54 * Flush the TLB and start new cycle. 55 */ 56 flush_tlb_all(); 57 /* 58 * Fix version. Note that we avoid version #0 59 * to distinguish NO_CONTEXT. 60 */ 61 if (!mc) 62 mmu_context_cache = mc = MMU_CONTEXT_FIRST_VERSION; 63 } 64 mm->context = mc; 65} 66 67/* 68 * Initialize the context related info for a new mm_struct 69 * instance. 70 */ 71static inline int init_new_context(struct task_struct *tsk, 72 struct mm_struct *mm) 73{ 74 mm->context = NO_CONTEXT; 75 return 0; 76} 77 78/* 79 * Destroy context related info for an mm_struct that is about 80 * to be put to rest. 81 */ 82static inline void destroy_context(struct mm_struct *mm) 83{ 84 /* Do nothing */ 85} 86 87static inline void set_asid(unsigned long asid) 88{ 89 /* XXX: We're destroying TLBEHI[8:31] */ 90 sysreg_write(TLBEHI, asid & MMU_CONTEXT_ASID_MASK); 91 cpu_sync_pipeline(); 92} 93 94static inline unsigned long get_asid(void) 95{ 96 unsigned long asid; 97 98 asid = sysreg_read(TLBEHI); 99 return asid & MMU_CONTEXT_ASID_MASK; 100} 101 102static inline void activate_context(struct mm_struct *mm) 103{ 104 get_mmu_context(mm); 105 set_asid(mm->context & MMU_CONTEXT_ASID_MASK); 106} 107 108static inline void switch_mm(struct mm_struct *prev, 109 struct mm_struct *next, 110 struct task_struct *tsk) 111{ 112 if (likely(prev != next)) { 113 unsigned long __pgdir = (unsigned long)next->pgd; 114 115 sysreg_write(PTBR, __pgdir); 116 activate_context(next); 117 } 118} 119 120#define deactivate_mm(tsk,mm) do { } while(0) 121 122#define activate_mm(prev, next) switch_mm((prev), (next), NULL) 123 124static inline void 125enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk) 126{ 127} 128 129 130static inline void enable_mmu(void) 131{ 132 sysreg_write(MMUCR, (SYSREG_BIT(MMUCR_S) 133 | SYSREG_BIT(E) 134 | SYSREG_BIT(MMUCR_I))); 135 nop(); nop(); nop(); nop(); nop(); nop(); nop(); nop(); 136 137 if (mmu_context_cache == NO_CONTEXT) 138 mmu_context_cache = MMU_CONTEXT_FIRST_VERSION; 139 140 set_asid(mmu_context_cache & MMU_CONTEXT_ASID_MASK); 141} 142 143static inline void disable_mmu(void) 144{ 145 sysreg_write(MMUCR, SYSREG_BIT(MMUCR_S)); 146} 147 148#endif /* __ASM_AVR32_MMU_CONTEXT_H */ 149