u-boot/arch/powerpc/lib/ticks.S

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/* SPDX-License-Identifier: GPL-2.0+ */
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/*
* (C) Copyright 2000, 2001
* Erik Theisen, Wave 7 Optics, etheisen@mindspring.com.
* base on code by
* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
*/
#include <ppc_asm.tmpl>
#include <ppc_defs.h>
#include <config.h>
#include <watchdog.h>
/*
* unsigned long long get_ticks(void);
*
* read timebase as "long long"
*/
.globl get_ticks
get_ticks:
1: mftbu r3
mftb r4
mftbu r5
cmp 0,r3,r5
bne 1b
blr
/*
* Delay for a number of ticks
*/
.globl wait_ticks
wait_ticks:
stwu r1, -16(r1)
mflr r0 /* save link register */
stw r0, 20(r1) /* Use r0 or GDB will be unhappy */
stw r14, 12(r1) /* save used registers */
stw r15, 8(r1)
mr r14, r3 /* save tick count */
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bl get_ticks /* Get start time */
/* Calculate end time */
addc r14, r4, r14 /* Compute end time lower */
addze r15, r3 /* and end time upper */
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WATCHDOG_RESET /* Trigger watchdog, if needed */
1: bl get_ticks /* Get current time */
subfc r4, r4, r14 /* Subtract current time from end time */
subfe. r3, r3, r15
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bge 1b /* Loop until time expired */
lwz r15, 8(r1) /* restore saved registers */
lwz r14, 12(r1)
lwz r0, 20(r1)
addi r1,r1,16
mtlr r0
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blr