xref: /arm-trusted-firmware/drivers/renesas/common/delay/micro_delay.c (revision 91f16700b400a8c0651d24a598fc48ee2997a0d7)
1*91f16700Schasinglulu /*
2*91f16700Schasinglulu  * Copyright (c) 2018-2020, Renesas Electronics Corporation. All rights reserved.
3*91f16700Schasinglulu  *
4*91f16700Schasinglulu  * SPDX-License-Identifier: BSD-3-Clause
5*91f16700Schasinglulu  */
6*91f16700Schasinglulu 
7*91f16700Schasinglulu #include <arch.h>
8*91f16700Schasinglulu #include <arch_helpers.h>
9*91f16700Schasinglulu 
10*91f16700Schasinglulu #include "micro_delay.h"
11*91f16700Schasinglulu 
12*91f16700Schasinglulu #define RCAR_CONV_MICROSEC		1000000U
13*91f16700Schasinglulu 
14*91f16700Schasinglulu void
15*91f16700Schasinglulu #if IMAGE_BL31
16*91f16700Schasinglulu 	__attribute__ ((section(".system_ram")))
17*91f16700Schasinglulu #endif
18*91f16700Schasinglulu 	rcar_micro_delay(uint64_t micro_sec)
19*91f16700Schasinglulu {
20*91f16700Schasinglulu 	uint64_t freq;
21*91f16700Schasinglulu 	uint64_t base_count;
22*91f16700Schasinglulu 	uint64_t get_count;
23*91f16700Schasinglulu 	uint64_t wait_time = 0U;
24*91f16700Schasinglulu 
25*91f16700Schasinglulu 	freq = read_cntfrq_el0();
26*91f16700Schasinglulu 	base_count = read_cntpct_el0();
27*91f16700Schasinglulu 	while (micro_sec > wait_time) {
28*91f16700Schasinglulu 		get_count = read_cntpct_el0();
29*91f16700Schasinglulu 		wait_time = ((get_count - base_count) * RCAR_CONV_MICROSEC) / freq;
30*91f16700Schasinglulu 	}
31*91f16700Schasinglulu }
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