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https://github.com/brain-hackers/u-boot-brain
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060ef09460
Generic Timer may contain an erroneous value. The workaround is to read it twice until getting the same value. Signed-off-by: York Sun <yorksun@freescale.com>
43 lines
930 B
C
43 lines
930 B
C
/*
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* (C) Copyright 2013
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* David Feng <fenghua@phytium.com.cn>
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include <common.h>
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#include <command.h>
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#include <asm/system.h>
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/*
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* Generic timer implementation of get_tbclk()
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*/
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unsigned long get_tbclk(void)
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{
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unsigned long cntfrq;
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asm volatile("mrs %0, cntfrq_el0" : "=r" (cntfrq));
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return cntfrq;
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}
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/*
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* Generic timer implementation of timer_read_counter()
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*/
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unsigned long timer_read_counter(void)
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{
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unsigned long cntpct;
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#ifdef CONFIG_SYS_FSL_ERRATUM_A008585
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/* This erratum number needs to be confirmed to match ARM document */
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unsigned long temp;
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#endif
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isb();
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asm volatile("mrs %0, cntpct_el0" : "=r" (cntpct));
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#ifdef CONFIG_SYS_FSL_ERRATUM_A008585
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asm volatile("mrs %0, cntpct_el0" : "=r" (temp));
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while (temp != cntpct) {
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asm volatile("mrs %0, cntpct_el0" : "=r" (cntpct));
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asm volatile("mrs %0, cntpct_el0" : "=r" (temp));
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}
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#endif
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return cntpct;
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}
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