Files
Linux_Drivers/u-boot-2021.10/arch/arm/mach-at91/arm926ejs/timer.c
sam.xiang f8fc109960 [uboot] create uboot from github:
repo: https://github.com/u-boot/u-boot
	commit: d80bb749fab53da72c4a0e09b8c2d2aaa3103c91

Change-Id: Ie6434426e1ec15bc08bb1832798e371f3fd5fb29
2023-03-10 20:30:57 +08:00

61 lines
1.3 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* (C) Copyright 2007-2008
* Stelian Pop <stelian@popies.net>
* Lead Tech Design <www.leadtechdesign.com>
*/
#include <common.h>
#include <init.h>
#include <time.h>
#include <asm/global_data.h>
#include <asm/io.h>
#include <asm/arch/hardware.h>
#include <asm/arch/at91_pit.h>
#include <asm/arch/clk.h>
#include <div64.h>
#if !defined(CONFIG_AT91FAMILY)
# error You need to define CONFIG_AT91FAMILY in your board config!
#endif
DECLARE_GLOBAL_DATA_PTR;
/*
* We're using the AT91CAP9/SAM9 PITC in 32 bit mode, by
* setting the 20 bit counter period to its maximum (0xfffff).
* (See the relevant data sheets to understand that this really works)
*
* We do also mimic the typical powerpc way of incrementing
* two 32 bit registers called tbl and tbu.
*
* Those registers increment at 1/16 the main clock rate.
*/
#define TIMER_LOAD_VAL 0xfffff
/*
* Use the PITC in full 32 bit incrementing mode
*/
int timer_init(void)
{
at91_pit_t *pit = (at91_pit_t *) ATMEL_BASE_PIT;
at91_periph_clk_enable(ATMEL_ID_SYS);
/* Enable PITC */
writel(TIMER_LOAD_VAL | AT91_PIT_MR_EN , &pit->mr);
gd->arch.timer_rate_hz = gd->arch.mck_rate_hz / 16;
return 0;
}
/*
* Return the number of timer ticks per second.
*/
ulong get_tbclk(void)
{
return gd->arch.timer_rate_hz;
}