1 files changed, 148 insertions, 0 deletions

diff --git a/arch/avr32/include/asm/mmu_context.h b/arch/avr32/include/asm/mmu_context.h
new file mode 100644
index 000000000000..27ff23407100
--- /dev/null
+++ b/arch/avr32/include/asm/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/sysreg.h>
+#include <asm-generic/mm_hooks.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 */