xref: /rk3399_rockchip-uboot/arch/arm/mach-at91/armv7/timer.c (revision 20680b560a17fb29c862de77930cfbf76b24f83c)
1*62011840SMasahiro Yamada /*
2*62011840SMasahiro Yamada  * (C) Copyright 2007-2008
3*62011840SMasahiro Yamada  * Stelian Pop <stelian@popies.net>
4*62011840SMasahiro Yamada  * Lead Tech Design <www.leadtechdesign.com>
5*62011840SMasahiro Yamada  *
6*62011840SMasahiro Yamada  * (C) Copyright 2013
7*62011840SMasahiro Yamada  * Bo Shen <voice.shen@atmel.com>
8*62011840SMasahiro Yamada  *
9*62011840SMasahiro Yamada  * SPDX-License-Identifier:	GPL-2.0+
10*62011840SMasahiro Yamada  */
11*62011840SMasahiro Yamada 
12*62011840SMasahiro Yamada #include <common.h>
13*62011840SMasahiro Yamada #include <asm/io.h>
14*62011840SMasahiro Yamada #include <asm/arch/hardware.h>
15*62011840SMasahiro Yamada #include <asm/arch/at91_pit.h>
16*62011840SMasahiro Yamada #include <asm/arch/clk.h>
17*62011840SMasahiro Yamada #include <div64.h>
18*62011840SMasahiro Yamada 
19*62011840SMasahiro Yamada #if !defined(CONFIG_AT91FAMILY)
20*62011840SMasahiro Yamada # error You need to define CONFIG_AT91FAMILY in your board config!
21*62011840SMasahiro Yamada #endif
22*62011840SMasahiro Yamada 
23*62011840SMasahiro Yamada DECLARE_GLOBAL_DATA_PTR;
24*62011840SMasahiro Yamada 
25*62011840SMasahiro Yamada /*
26*62011840SMasahiro Yamada  * We're using the SAMA5D3x PITC in 32 bit mode, by
27*62011840SMasahiro Yamada  * setting the 20 bit counter period to its maximum (0xfffff).
28*62011840SMasahiro Yamada  * (See the relevant data sheets to understand that this really works)
29*62011840SMasahiro Yamada  *
30*62011840SMasahiro Yamada  * We do also mimic the typical powerpc way of incrementing
31*62011840SMasahiro Yamada  * two 32 bit registers called tbl and tbu.
32*62011840SMasahiro Yamada  *
33*62011840SMasahiro Yamada  * Those registers increment at 1/16 the main clock rate.
34*62011840SMasahiro Yamada  */
35*62011840SMasahiro Yamada 
36*62011840SMasahiro Yamada #define TIMER_LOAD_VAL	0xfffff
37*62011840SMasahiro Yamada 
38*62011840SMasahiro Yamada /*
39*62011840SMasahiro Yamada  * Use the PITC in full 32 bit incrementing mode
40*62011840SMasahiro Yamada  */
timer_init(void)41*62011840SMasahiro Yamada int timer_init(void)
42*62011840SMasahiro Yamada {
43*62011840SMasahiro Yamada 	at91_pit_t *pit = (at91_pit_t *)ATMEL_BASE_PIT;
44*62011840SMasahiro Yamada 
45*62011840SMasahiro Yamada 	/* Enable PITC Clock */
46*62011840SMasahiro Yamada 	at91_periph_clk_enable(ATMEL_ID_PIT);
47*62011840SMasahiro Yamada 
48*62011840SMasahiro Yamada 	/* Enable PITC */
49*62011840SMasahiro Yamada 	writel(TIMER_LOAD_VAL | AT91_PIT_MR_EN , &pit->mr);
50*62011840SMasahiro Yamada 
51*62011840SMasahiro Yamada 	gd->arch.timer_rate_hz = get_pit_clk_rate() / 16;
52*62011840SMasahiro Yamada 
53*62011840SMasahiro Yamada 	return 0;
54*62011840SMasahiro Yamada }
55*62011840SMasahiro Yamada 
56*62011840SMasahiro Yamada /*
57*62011840SMasahiro Yamada  * Return the number of timer ticks per second.
58*62011840SMasahiro Yamada  */
get_tbclk(void)59*62011840SMasahiro Yamada ulong get_tbclk(void)
60*62011840SMasahiro Yamada {
61*62011840SMasahiro Yamada 	return gd->arch.timer_rate_hz;
62*62011840SMasahiro Yamada }
63