#ifndef __ASM_SH64_MMU_CONTEXT_H
  #define __ASM_SH64_MMU_CONTEXT_H
  
  /*
   * This file is subject to the terms and conditions of the GNU General Public
   * License.  See the file "COPYING" in the main directory of this archive
   * for more details.
   *
   * include/asm-sh64/mmu_context.h
   *
   * Copyright (C) 2000, 2001  Paolo Alberelli
   * Copyright (C) 2003  Paul Mundt
   *
   * ASID handling idea taken from MIPS implementation.
   *
   */
  
  #ifndef __ASSEMBLY__
  
  /*
   * Cache of MMU context last used.
   *
   * The MMU "context" consists of two things:
   *   (a) TLB cache version (or cycle, top 24 bits of mmu_context_cache)
   *   (b) ASID (Address Space IDentifier, bottom 8 bits of mmu_context_cache)
   */
  extern unsigned long mmu_context_cache;

  #include <asm/page.h>

  #include <asm-generic/mm_hooks.h>

  
  /* Current mm's pgd */
  extern pgd_t *mmu_pdtp_cache;
  
  #define SR_ASID_MASK		0xffffffffff00ffffULL
  #define SR_ASID_SHIFT		16
  
  #define MMU_CONTEXT_ASID_MASK		0x000000ff
  #define MMU_CONTEXT_VERSION_MASK	0xffffff00
  #define MMU_CONTEXT_FIRST_VERSION	0x00000100
  #define NO_CONTEXT			0
  
  /* ASID is 8-bit value, so it can't be 0x100 */
  #define MMU_NO_ASID			0x100
  
  
  /*
   * Virtual Page Number mask
   */
  #define MMU_VPN_MASK	0xfffff000

  static inline void

  get_new_mmu_context(struct mm_struct *mm)
  {
  	extern void flush_tlb_all(void);
  	extern void flush_cache_all(void);
  
  	unsigned long mc = ++mmu_context_cache;
  
  	if (!(mc & MMU_CONTEXT_ASID_MASK)) {
  		/* We exhaust ASID of this version.
  		   Flush all TLB and start new cycle. */
  		flush_tlb_all();
  		/* We have to flush all caches as ASIDs are
                     used in cache */
  		flush_cache_all();
  		/* Fix version if needed.
  		   Note that we avoid version #0/asid #0 to distingush NO_CONTEXT. */
  		if (!mc)
  			mmu_context_cache = mc = MMU_CONTEXT_FIRST_VERSION;
  	}
  	mm->context = mc;
  }
  
  /*
   * Get MMU context if needed.
   */
  static __inline__ void
  get_mmu_context(struct mm_struct *mm)
  {
  	if (mm) {
  		unsigned long mc = mmu_context_cache;
  		/* Check if we have old version of context.
  		   If it's old, we need to get new context with new version. */
  		if ((mm->context ^ mc) & MMU_CONTEXT_VERSION_MASK)
  			get_new_mmu_context(mm);
  	}
  }
  
  /*
   * 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)
  {
  	extern void flush_tlb_mm(struct mm_struct *mm);
  
  	/* Well, at least free TLB entries */
  	flush_tlb_mm(mm);
  }
  
  #endif	/* __ASSEMBLY__ */
  
  /* Common defines */
  #define TLB_STEP	0x00000010
  #define TLB_PTEH	0x00000000
  #define TLB_PTEL	0x00000008
  
  /* PTEH defines */
  #define PTEH_ASID_SHIFT	2
  #define PTEH_VALID	0x0000000000000001
  #define PTEH_SHARED	0x0000000000000002
  #define PTEH_MATCH_ASID	0x00000000000003ff
  
  #ifndef __ASSEMBLY__
  /* This has to be a common function because the next location to fill
   * information is shared. */
  extern void __do_tlb_refill(unsigned long address, unsigned long long is_text_not_data, pte_t *pte);
  
  /* Profiling counter. */
  #ifdef CONFIG_SH64_PROC_TLB
  extern unsigned long long calls_to_do_fast_page_fault;
  #endif
  
  static inline unsigned long get_asid(void)
  {
  	unsigned long long sr;
  
  	asm volatile ("getcon   " __SR ", %0
  \t"
  		      : "=r" (sr));
  
  	sr = (sr >> SR_ASID_SHIFT) & MMU_CONTEXT_ASID_MASK;
  	return (unsigned long) sr;
  }
  
  /* Set ASID into SR */
  static inline void set_asid(unsigned long asid)
  {
  	unsigned long long sr, pc;
  
  	asm volatile ("getcon	" __SR ", %0" : "=r" (sr));
  
  	sr = (sr & SR_ASID_MASK) | (asid << SR_ASID_SHIFT);
  
  	/*
  	 * It is possible that this function may be inlined and so to avoid
  	 * the assembler reporting duplicate symbols we make use of the gas trick
  	 * of generating symbols using numerics and forward reference.
  	 */
  	asm volatile ("movi	1, %1
  \t"
  		      "shlli	%1, 28, %1
  \t"
  		      "or	%0, %1, %1
  \t"
  		      "putcon	%1, " __SR "
  \t"
  		      "putcon	%0, " __SSR "
  \t"
  		      "movi	1f, %1
  \t"
  		      "ori	%1, 1 , %1
  \t"
  		      "putcon	%1, " __SPC "
  \t"
  		      "rte
  "
  		      "1:
  \t"
  		      : "=r" (sr), "=r" (pc) : "0" (sr));
  }
  
  /*
   * After we have set current->mm to a new value, this activates
   * the context for the new mm so we see the new mappings.
   */
  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 (prev != next) {
  		mmu_pdtp_cache = next->pgd;
  		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)
  {
  }
  
  #endif	/* __ASSEMBLY__ */
  
  #endif /* __ASM_SH64_MMU_CONTEXT_H */