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__ */ 59