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 #include <asm/pgtable-prot.h>
  24
  25 /*
  26  * Here we define all the compile-time 'special' virtual
  27  * addresses. The point is to have a constant address at
  28  * compile time, but to set the physical address only
  29  * in the boot process.
  30  *
  31  * These 'compile-time allocated' memory buffers are
  32  * page-sized. Use set_fixmap(idx,phys) to associate
  33  * physical memory with fixmap indices.
  34  *
  35  */
  36 enum fixed_addresses {
  37         FIX_HOLE,
  38
  39         /*
  40          * Reserve a virtual window for the FDT that is 2 MB larger than the
  41          * maximum supported size, and put it at the top of the fixmap region.
  42          * The additional space ensures that any FDT that does not exceed
  43          * MAX_FDT_SIZE can be mapped regardless of whether it crosses any
  44          * 2 MB alignment boundaries.
  45          *
  46          * Keep this at the top so it remains 2 MB aligned.
  47          */
  48 #define FIX_FDT_SIZE            (MAX_FDT_SIZE + SZ_2M)
  49         FIX_FDT_END,
  50         FIX_FDT = FIX_FDT_END + FIX_FDT_SIZE / PAGE_SIZE - 1,
  51
  52         FIX_EARLYCON_MEM_BASE,
  53         FIX_TEXT_POKE0,
  54         __end_of_permanent_fixed_addresses,
  55
  56         /*
  57          * Temporary boot-time mappings, used by early_ioremap(),
  58          * before ioremap() is functional.
  59          */
  60 #define NR_FIX_BTMAPS           (SZ_256K / PAGE_SIZE)
  61 #define FIX_BTMAPS_SLOTS        7
  62 #define TOTAL_FIX_BTMAPS        (NR_FIX_BTMAPS * FIX_BTMAPS_SLOTS)
  63
  64         FIX_BTMAP_END = __end_of_permanent_fixed_addresses,
  65         FIX_BTMAP_BEGIN = FIX_BTMAP_END + TOTAL_FIX_BTMAPS - 1,
  66
  67         /*
  68          * Used for kernel page table creation, so unmapped memory may be used
  69          * for tables.
  70          */
  71         FIX_PTE,
  72         FIX_PMD,
  73         FIX_PUD,
  74         FIX_PGD,
  75
  76         __end_of_fixed_addresses
  77 };
  78
  79 #define FIXADDR_SIZE    (__end_of_permanent_fixed_addresses << PAGE_SHIFT)
  80 #define FIXADDR_START   (FIXADDR_TOP - FIXADDR_SIZE)
  81
  82 #define FIXMAP_PAGE_IO     __pgprot(PROT_DEVICE_nGnRE)
  83
  84 void __init early_fixmap_init(void);
  85
  86 #define __early_set_fixmap __set_fixmap
  87
  88 #define __late_set_fixmap __set_fixmap
  89 #define __late_clear_fixmap(idx) __set_fixmap((idx), 0, FIXMAP_PAGE_CLEAR)
  90
  91 extern void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot);
  92
  93 #include <asm-generic/fixmap.h>
  94
  95 #endif /* !__ASSEMBLY__ */
  96 #endif /* _ASM_ARM64_FIXMAP_H */