u-boot/arch/arm/mach-socfpga/timer_s10.c

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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2017-2022 Intel Corporation <www.intel.com>
*
*/
#include <common.h>
#include <init.h>
#include <div64.h>
#include <asm/io.h>
#include <asm/arch/timer.h>
/*
* Timer initialization
*/
int timer_init(void)
{
#ifdef CONFIG_SPL_BUILD
int enable = 0x3; /* timer enable + output signal masked */
int loadval = ~0;
/* enable system counter */
writel(enable, SOCFPGA_GTIMER_SEC_ADDRESS);
/* enable processor pysical counter */
asm volatile("msr cntp_ctl_el0, %0" : : "r" (enable));
asm volatile("msr cntp_tval_el0, %0" : : "r" (loadval));
#endif
return 0;
}
__always_inline u64 __get_time_stamp(void)
{
u64 cntpct;
isb();
asm volatile("mrs %0, cntpct_el0" : "=r" (cntpct));
return cntpct;
}
__always_inline uint64_t __usec_to_tick(unsigned long usec)
{
u64 tick = usec;
u64 cntfrq;
asm volatile("mrs %0, cntfrq_el0" : "=r" (cntfrq));
tick *= cntfrq;
do_div(tick, 1000000);
return tick;
}
__always_inline void __udelay(unsigned long usec)
{
/* get current timestamp */
u64 tmp = __get_time_stamp() + __usec_to_tick(usec);
while (__get_time_stamp() < tmp + 1) /* loop till event */
;
}