1 files changed, 118 insertions, 0 deletions

diff --git a/arch/mips/include/asm/fixmap.h b/arch/mips/include/asm/fixmap.h
new file mode 100644
index 000000000000..9cc8522a394f
--- /dev/null
+++ b/arch/mips/include/asm/fixmap.h
@@ -0,0 +1,118 @@
+/*
+ * fixmap.h: compile-time virtual memory allocation
+ *
+ * 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.
+ *
+ * Copyright (C) 1998 Ingo Molnar
+ *
+ * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
+ */
+
+#ifndef _ASM_FIXMAP_H
+#define _ASM_FIXMAP_H
+
+#include <asm/page.h>
+#ifdef CONFIG_HIGHMEM
+#include <linux/threads.h>
+#include <asm/kmap_types.h>
+#endif
+
+/*
+ * Here we define all the compile-time 'special' virtual
+ * addresses. The point is to have a constant address at
+ * compile time, but to set the physical address only
+ * in the boot process. We allocate these special  addresses
+ * from the end of virtual memory (0xfffff000) backwards.
+ * Also this lets us do fail-safe vmalloc(), we
+ * can guarantee that these special addresses and
+ * vmalloc()-ed addresses never overlap.
+ *
+ * these 'compile-time allocated' memory buffers are
+ * fixed-size 4k pages. (or larger if used with an increment
+ * highger than 1) use fixmap_set(idx,phys) to associate
+ * physical memory with fixmap indices.
+ *
+ * TLB entries of such buffers will not be flushed across
+ * task switches.
+ */
+
+/*
+ * on UP currently we will have no trace of the fixmap mechanizm,
+ * no page table allocations, etc. This might change in the
+ * future, say framebuffers for the console driver(s) could be
+ * fix-mapped?
+ */
+enum fixed_addresses {
+#define FIX_N_COLOURS 8
+        FIX_CMAP_BEGIN,
+#ifdef CONFIG_MIPS_MT_SMTC
+        FIX_CMAP_END = FIX_CMAP_BEGIN + (FIX_N_COLOURS * NR_CPUS),
+#else
+        FIX_CMAP_END = FIX_CMAP_BEGIN + FIX_N_COLOURS,
+#endif
+#ifdef CONFIG_HIGHMEM
+        /* reserved pte's for temporary kernel mappings */
+        FIX_KMAP_BEGIN = FIX_CMAP_END + 1,
+        FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
+#endif
+        __end_of_fixed_addresses
+};
+
+/*
+ * used by vmalloc.c.
+ *
+ * Leave one empty page between vmalloc'ed areas and
+ * the start of the fixmap, and leave one page empty
+ * at the top of mem..
+ */
+#if defined(CONFIG_CPU_TX39XX) || defined(CONFIG_CPU_TX49XX)
+#define FIXADDR_TOP     ((unsigned long)(long)(int)(0xff000000 - 0x20000))
+#else
+#define FIXADDR_TOP     ((unsigned long)(long)(int)0xfffe0000)
+#endif
+#define FIXADDR_SIZE    (__end_of_fixed_addresses << PAGE_SHIFT)
+#define FIXADDR_START   (FIXADDR_TOP - FIXADDR_SIZE)
+
+#define __fix_to_virt(x)        (FIXADDR_TOP - ((x) << PAGE_SHIFT))
+#define __virt_to_fix(x)        ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
+
+extern void __this_fixmap_does_not_exist(void);
+
+/*
+ * 'index to address' translation. If anyone tries to use the idx
+ * directly without tranlation, we catch the bug with a NULL-deference
+ * kernel oops. Illegal ranges of incoming indices are caught too.
+ */
+static inline unsigned long fix_to_virt(const unsigned int idx)
+{
+        /*
+         * this branch gets completely eliminated after inlining,
+         * except when someone tries to use fixaddr indices in an
+         * illegal way. (such as mixing up address types or using
+         * out-of-range indices).
+         *
+         * If it doesn't get removed, the linker will complain
+         * loudly with a reasonably clear error message..
+         */
+        if (idx >= __end_of_fixed_addresses)
+                __this_fixmap_does_not_exist();
+
+        return __fix_to_virt(idx);
+}
+
+static inline unsigned long virt_to_fix(const unsigned long vaddr)
+{
+        BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
+        return __virt_to_fix(vaddr);
+}
+
+/*
+ * Called from pgtable_init()
+ */
+extern void fixrange_init(unsigned long start, unsigned long end,
+        pgd_t *pgd_base);
+
+
+#endif