arch/arm64/include/asm/fixmap.h

   1 /*
   2  * fixmap.h: compile-time virtual memory allocation
   3  *
   4  * This file is subject to the terms and conditions of the GNU General Public
   5  * License.  See the file "COPYING" in the main directory of this archive
   6  * for more details.
   7  *
   8  * Copyright (C) 1998 Ingo Molnar
   9  * Copyright (C) 2013 Mark Salter <msalter@redhat.com>
  10  *
  11  * Adapted from arch/x86 version.
  12  *
  13  */
  14
  15 #ifndef _ASM_ARM64_FIXMAP_H
  16 #define _ASM_ARM64_FIXMAP_H
  17
  18 #ifndef __ASSEMBLY__
  19 #include <linux/kernel.h>
  20 #include <linux/sizes.h>
  21 #include <asm/boot.h>
  22 #include <asm/page.h>
  23
  24 /*
  25  * Here we define all the compile-time 'special' virtual
  26  * addresses. The point is to have a constant address at
  27  * compile time, but to set the physical address only
  28  * in the boot process.
  29  *
  30  * These 'compile-time allocated' memory buffers are
  31  * page-sized. Use set_fixmap(idx,phys) to associate
  32  * physical memory with fixmap indices.
  33  *
  34  */
  35 enum fixed_addresses {
  36         FIX_HOLE,
  37
  38         /*
  39          * Reserve a virtual window for the FDT that is 2 MB larger than the
  40          * maximum supported size, and put it at the top of the fixmap region.
  41          * The additional space ensures that any FDT that does not exceed
  42          * MAX_FDT_SIZE can be mapped regardless of whether it crosses any
  43          * 2 MB alignment boundaries.
  44          *
  45          * Keep this at the top so it remains 2 MB aligned.
  46          */
  47 #define FIX_FDT_SIZE            (MAX_FDT_SIZE + SZ_2M)
  48         FIX_FDT_END,
  49         FIX_FDT = FIX_FDT_END + FIX_FDT_SIZE / PAGE_SIZE - 1,
  50
  51         FIX_EARLYCON_MEM_BASE,
  52         FIX_TEXT_POKE0,
  53         __end_of_permanent_fixed_addresses,
  54
  55         /*
  56          * Temporary boot-time mappings, used by early_ioremap(),
  57          * before ioremap() is functional.
  58          */
  59 #define NR_FIX_BTMAPS           (SZ_256K / PAGE_SIZE)
  60 #define FIX_BTMAPS_SLOTS        7
  61 #define TOTAL_FIX_BTMAPS        (NR_FIX_BTMAPS * FIX_BTMAPS_SLOTS)
  62
  63         FIX_BTMAP_END = __end_of_permanent_fixed_addresses,
  64         FIX_BTMAP_BEGIN = FIX_BTMAP_END + TOTAL_FIX_BTMAPS - 1,
  65
  66         /*
  67          * Used for kernel page table creation, so unmapped memory may be used
  68          * for tables.
  69          */
  70         FIX_PTE,
  71         FIX_PMD,
  72         FIX_PUD,
  73         FIX_PGD,
  74
  75         __end_of_fixed_addresses
  76 };
  77
  78 #define FIXADDR_SIZE    (__end_of_permanent_fixed_addresses << PAGE_SHIFT)
  79 #define FIXADDR_START   (FIXADDR_TOP - FIXADDR_SIZE)
  80
  81 #define FIXMAP_PAGE_IO     __pgprot(PROT_DEVICE_nGnRE)
  82
  83 void __init early_fixmap_init(void);
  84
  85 #define __early_set_fixmap __set_fixmap
  86
  87 #define __late_set_fixmap __set_fixmap
  88 #define __late_clear_fixmap(idx) __set_fixmap((idx), 0, FIXMAP_PAGE_CLEAR)
  89
  90 extern void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot);
  91
  92 #include <asm-generic/fixmap.h>
  93
  94 #endif /* !__ASSEMBLY__ */
  95 #endif /* _ASM_ARM64_FIXMAP_H */