arch/arm/include/asm/macro.h

   1 /*
   2  * include/asm-arm/macro.h
   3  *
   4  * Copyright (C) 2009 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
   5  *
   6  * SPDX-License-Identifier:     GPL-2.0+
   7  */
   8
   9 #ifndef __ASM_ARM_MACRO_H__
  10 #define __ASM_ARM_MACRO_H__
  11 #ifdef __ASSEMBLY__
  12
  13 /*
  14  * These macros provide a convenient way to write 8, 16 and 32 bit data
  15  * to any address.
  16  * Registers r4 and r5 are used, any data in these registers are
  17  * overwritten by the macros.
  18  * The macros are valid for any ARM architecture, they do not implement
  19  * any memory barriers so caution is recommended when using these when the
  20  * caches are enabled or on a multi-core system.
  21  */
  22
  23 .macro  write32, addr, data
  24         ldr     r4, =\addr
  25         ldr     r5, =\data
  26         str     r5, [r4]
  27 .endm
  28
  29 .macro  write16, addr, data
  30         ldr     r4, =\addr
  31         ldrh    r5, =\data
  32         strh    r5, [r4]
  33 .endm
  34
  35 .macro  write8, addr, data
  36         ldr     r4, =\addr
  37         ldrb    r5, =\data
  38         strb    r5, [r4]
  39 .endm
  40
  41 /*
  42  * This macro generates a loop that can be used for delays in the code.
  43  * Register r4 is used, any data in this register is overwritten by the
  44  * macro.
  45  * The macro is valid for any ARM architeture. The actual time spent in the
  46  * loop will vary from CPU to CPU though.
  47  */
  48
  49 .macro  wait_timer, time
  50         ldr     r4, =\time
  51 1:
  52         nop
  53         subs    r4, r4, #1
  54         bcs     1b
  55 .endm
  56
  57 #endif /* __ASSEMBLY__ */
  58 #endif /* __ASM_ARM_MACRO_H__ */