arch/arm/lib/delay-loop.S

/* SPDX-License-Identifier: GPL-2.0-only */
/*
 *  linux/arch/arm/lib/delay.S
 *
 *  Copyright (C) 1995, 1996 Russell King
 */
#include <linux/linkage.h>
#include <linux/cfi_types.h>
#include <asm/assembler.h>
#include <asm/delay.h>

#ifdef CONFIG_ARCH_RPC
		.arch	armv4
#endif

		.text

.LC0:		.word	loops_per_jiffy
.LC1:		.word	UDELAY_MULT

/*
 * loops = r0 * HZ * loops_per_jiffy / 1000000
 *
 * r0  <= 2000
 * HZ  <= 1000
 */

SYM_TYPED_FUNC_START(__loop_udelay)
		ldr	r2, .LC1
		mul	r0, r2, r0		@ r0 = delay_us * UDELAY_MULT
		b	__loop_const_udelay
SYM_FUNC_END(__loop_udelay)

SYM_TYPED_FUNC_START(__loop_const_udelay)	@ 0 <= r0 <= 0xfffffaf0
		ldr	r2, .LC0
		ldr	r2, [r2]
		umull	r1, r0, r2, r0		@ r0-r1 = r0 * loops_per_jiffy
		adds	r1, r1, #0xffffffff	@ rounding up ...
		adcs	r0, r0, r0		@ and right shift by 31
		reteq	lr
		b	__loop_delay
SYM_FUNC_END(__loop_const_udelay)

		.align 3

@ Delay routine
SYM_TYPED_FUNC_START(__loop_delay)
		subs	r0, r0, #1
#if 0
		retls	lr
		subs	r0, r0, #1
		retls	lr
		subs	r0, r0, #1
		retls	lr
		subs	r0, r0, #1
		retls	lr
		subs	r0, r0, #1
		retls	lr
		subs	r0, r0, #1
		retls	lr
		subs	r0, r0, #1
		retls	lr
		subs	r0, r0, #1
#endif
		bhi	__loop_delay
		ret	lr
SYM_FUNC_END(__loop_delay)
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-04 10:11:33 +02:00			`/* SPDX-License-Identifier: GPL-2.0-only */`
Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00			`/*`
			`* linux/arch/arm/lib/delay.S`
			`*`
			`* Copyright (C) 1995, 1996 Russell King`
			`*/`
			`#include <linux/linkage.h>`
ARM: 9390/2: lib: Annotate loop delay instructions for CFI 2024-04-23 08:50:38 +01:00			`#include <linux/cfi_types.h>`
Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00			`#include <asm/assembler.h>`
ARM: 7452/1: delay: allow timer-based delay implementation to be selected 2012-07-06 15:47:17 +01:00			`#include <asm/delay.h>`
ARM: 8306/1: loop_udelay: remove bogomips value limitation 2015-02-25 22:50:39 +01:00
ARM: 9263/1: use .arch directives instead of assembler command line flags 2022-10-24 20:44:41 +01:00			`#ifdef CONFIG_ARCH_RPC`
			`.arch armv4`
			`#endif`

Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00			`.text`

[ARM] 3152/1: make various assembly local labels actually local (the rest) 2005-11-11 21:51:49 +00:00			`.LC0: .word loops_per_jiffy`
ARM: 7452/1: delay: allow timer-based delay implementation to be selected 2012-07-06 15:47:17 +01:00			`.LC1: .word UDELAY_MULT`
Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
			`/*`
ARM: 8619/1: udelay: document the various constants 2016-10-07 05:38:35 +01:00			`* loops = r0 * HZ * loops_per_jiffy / 1000000`
			`*`
[ARM] 3346/1: Fix udelay() for HZ values different from 100 2006-03-20 17:10:09 +00:00			`* r0 <= 2000`
			`* HZ <= 1000`
Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00			`*/`
[ARM] 3346/1: Fix udelay() for HZ values different from 100 2006-03-20 17:10:09 +00:00
ARM: 9390/2: lib: Annotate loop delay instructions for CFI 2024-04-23 08:50:38 +01:00			`SYM_TYPED_FUNC_START(__loop_udelay)`
[ARM] 3346/1: Fix udelay() for HZ values different from 100 2006-03-20 17:10:09 +00:00			`ldr r2, .LC1`
ARM: 8619/1: udelay: document the various constants 2016-10-07 05:38:35 +01:00			`mul r0, r2, r0 @ r0 = delay_us * UDELAY_MULT`
ARM: 9390/2: lib: Annotate loop delay instructions for CFI 2024-04-23 08:50:38 +01:00			`b __loop_const_udelay`
			`SYM_FUNC_END(__loop_udelay)`

			`SYM_TYPED_FUNC_START(__loop_const_udelay) @ 0 <= r0 <= 0xfffffaf0`
[ARM] 3152/1: make various assembly local labels actually local (the rest) 2005-11-11 21:51:49 +00:00			`ldr r2, .LC0`
ARM: 8306/1: loop_udelay: remove bogomips value limitation 2015-02-25 22:50:39 +01:00			`ldr r2, [r2]`
ARM: 8619/1: udelay: document the various constants 2016-10-07 05:38:35 +01:00			`umull r1, r0, r2, r0 @ r0-r1 = r0 * loops_per_jiffy`
			`adds r1, r1, #0xffffffff @ rounding up ...`
			`adcs r0, r0, r0 @ and right shift by 31`
ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-06-30 16:29:12 +01:00			`reteq lr`
ARM: 9390/2: lib: Annotate loop delay instructions for CFI 2024-04-23 08:50:38 +01:00			`b __loop_delay`
			`SYM_FUNC_END(__loop_const_udelay)`
Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
ARM: 7907/1: lib: delay-loop: Add align directive to fix BogoMIPS calculation 2013-11-30 15:24:42 +01:00			`.align 3`
Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
			`@ Delay routine`
ARM: 9390/2: lib: Annotate loop delay instructions for CFI 2024-04-23 08:50:38 +01:00			`SYM_TYPED_FUNC_START(__loop_delay)`
Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00			`subs r0, r0, #1`
			`#if 0`
ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-06-30 16:29:12 +01:00			`retls lr`
Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00			`subs r0, r0, #1`
ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-06-30 16:29:12 +01:00			`retls lr`
Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00			`subs r0, r0, #1`
ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-06-30 16:29:12 +01:00			`retls lr`
Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00			`subs r0, r0, #1`
ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-06-30 16:29:12 +01:00			`retls lr`
Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00			`subs r0, r0, #1`
ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-06-30 16:29:12 +01:00			`retls lr`
Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00			`subs r0, r0, #1`
ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-06-30 16:29:12 +01:00			`retls lr`
Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00			`subs r0, r0, #1`
ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-06-30 16:29:12 +01:00			`retls lr`
Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00			`subs r0, r0, #1`
			`#endif`
ARM: 7452/1: delay: allow timer-based delay implementation to be selected 2012-07-06 15:47:17 +01:00			`bhi __loop_delay`
ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-06-30 16:29:12 +01:00			`ret lr`
ARM: 9390/2: lib: Annotate loop delay instructions for CFI 2024-04-23 08:50:38 +01:00			`SYM_FUNC_END(__loop_delay)`