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Diffstat (limited to 'include/asm-avr32/mmu_context.h')
| -rw-r--r-- | include/asm-avr32/mmu_context.h | 148 |
1 files changed, 148 insertions, 0 deletions
diff --git a/include/asm-avr32/mmu_context.h b/include/asm-avr32/mmu_context.h new file mode 100644 index 0000000..31add1a --- /dev/null +++ b/include/asm-avr32/mmu_context.h @@ -0,0 +1,148 @@ +/* + * Copyright (C) 2004-2006 Atmel Corporation + * + * ASID handling taken from SH implementation. + * Copyright (C) 1999 Niibe Yutaka + * Copyright (C) 2003 Paul Mundt + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ +#ifndef __ASM_AVR32_MMU_CONTEXT_H +#define __ASM_AVR32_MMU_CONTEXT_H + +#include <asm/tlbflush.h> +#include <asm/pgalloc.h> +#include <asm/sysreg.h> + +/* + * The MMU "context" consists of two things: + * (a) TLB cache version + * (b) ASID (Address Space IDentifier) + */ +#define MMU_CONTEXT_ASID_MASK 0x000000ff +#define MMU_CONTEXT_VERSION_MASK 0xffffff00 +#define MMU_CONTEXT_FIRST_VERSION 0x00000100 +#define NO_CONTEXT 0 + +#define MMU_NO_ASID 0x100 + +/* Virtual Page Number mask */ +#define MMU_VPN_MASK 0xfffff000 + +/* Cache of MMU context last used */ +extern unsigned long mmu_context_cache; + +/* + * Get MMU context if needed + */ +static inline void +get_mmu_context(struct mm_struct *mm) +{ + unsigned long mc = mmu_context_cache; + + if (((mm->context ^ mc) & MMU_CONTEXT_VERSION_MASK) == 0) + /* It's up to date, do nothing */ + return; + + /* It's old, we need to get new context with new version */ + mc = ++mmu_context_cache; + if (!(mc & MMU_CONTEXT_ASID_MASK)) { + /* + * We have exhausted all ASIDs of this version. + * Flush the TLB and start new cycle. + */ + flush_tlb_all(); + /* + * Fix version. Note that we avoid version #0 + * to distinguish NO_CONTEXT. + */ + if (!mc) + mmu_context_cache = mc = MMU_CONTEXT_FIRST_VERSION; + } + mm->context = mc; +} + +/* + * Initialize the context related info for a new mm_struct + * instance. + */ +static inline int init_new_context(struct task_struct *tsk, + struct mm_struct *mm) +{ + mm->context = NO_CONTEXT; + return 0; +} + +/* + * Destroy context related info for an mm_struct that is about + * to be put to rest. + */ +static inline void destroy_context(struct mm_struct *mm) +{ + /* Do nothing */ +} + +static inline void set_asid(unsigned long asid) +{ + /* XXX: We're destroying TLBEHI[8:31] */ + sysreg_write(TLBEHI, asid & MMU_CONTEXT_ASID_MASK); + cpu_sync_pipeline(); +} + +static inline unsigned long get_asid(void) +{ + unsigned long asid; + + asid = sysreg_read(TLBEHI); + return asid & MMU_CONTEXT_ASID_MASK; +} + +static inline void activate_context(struct mm_struct *mm) +{ + get_mmu_context(mm); + set_asid(mm->context & MMU_CONTEXT_ASID_MASK); +} + +static inline void switch_mm(struct mm_struct *prev, + struct mm_struct *next, + struct task_struct *tsk) +{ + if (likely(prev != next)) { + unsigned long __pgdir = (unsigned long)next->pgd; + + sysreg_write(PTBR, __pgdir); + activate_context(next); + } +} + +#define deactivate_mm(tsk,mm) do { } while(0) + +#define activate_mm(prev, next) switch_mm((prev), (next), NULL) + +static inline void +enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk) +{ +} + + +static inline void enable_mmu(void) +{ + sysreg_write(MMUCR, (SYSREG_BIT(MMUCR_S) + | SYSREG_BIT(E) + | SYSREG_BIT(MMUCR_I))); + nop(); nop(); nop(); nop(); nop(); nop(); nop(); nop(); + + if (mmu_context_cache == NO_CONTEXT) + mmu_context_cache = MMU_CONTEXT_FIRST_VERSION; + + set_asid(mmu_context_cache & MMU_CONTEXT_ASID_MASK); +} + +static inline void disable_mmu(void) +{ + sysreg_write(MMUCR, SYSREG_BIT(MMUCR_S)); +} + +#endif /* __ASM_AVR32_MMU_CONTEXT_H */ |