124 lines
2.6 KiB
C
124 lines
2.6 KiB
C
/*
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* (C) Copyright 2007-2008
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* Stelian Pop <stelian@popies.net>
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* Lead Tech Design <www.leadtechdesign.com>
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*
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* (C) Copyright 2013
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* Bo Shen <voice.shen@atmel.com>
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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 <asm/io.h>
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#include <asm/arch/hardware.h>
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#include <asm/arch/at91_pit.h>
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#include <asm/arch/at91_pmc.h>
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#include <asm/arch/clk.h>
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#include <div64.h>
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#if !defined(CONFIG_AT91FAMILY)
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# error You need to define CONFIG_AT91FAMILY in your board config!
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#endif
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DECLARE_GLOBAL_DATA_PTR;
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/*
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* We're using the SAMA5D3x PITC in 32 bit mode, by
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* setting the 20 bit counter period to its maximum (0xfffff).
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* (See the relevant data sheets to understand that this really works)
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*
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* We do also mimic the typical powerpc way of incrementing
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* two 32 bit registers called tbl and tbu.
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*
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* Those registers increment at 1/16 the main clock rate.
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*/
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#define TIMER_LOAD_VAL 0xfffff
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static inline unsigned long long tick_to_time(unsigned long long tick)
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{
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tick *= CONFIG_SYS_HZ;
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do_div(tick, gd->arch.timer_rate_hz);
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return tick;
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}
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static inline unsigned long long usec_to_tick(unsigned long long usec)
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{
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usec *= gd->arch.timer_rate_hz;
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do_div(usec, 1000000);
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return usec;
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}
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/*
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* Use the PITC in full 32 bit incrementing mode
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*/
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int timer_init(void)
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{
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at91_pit_t *pit = (at91_pit_t *)ATMEL_BASE_PIT;
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/* Enable PITC Clock */
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at91_periph_clk_enable(ATMEL_ID_PIT);
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/* Enable PITC */
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writel(TIMER_LOAD_VAL | AT91_PIT_MR_EN , &pit->mr);
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gd->arch.timer_rate_hz = gd->arch.mck_rate_hz / 16;
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gd->arch.tbu = 0;
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gd->arch.tbl = 0;
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return 0;
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}
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/*
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* Get the current 64 bit timer tick count
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*/
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unsigned long long get_ticks(void)
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{
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at91_pit_t *pit = (at91_pit_t *)ATMEL_BASE_PIT;
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ulong now = readl(&pit->piir);
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/* increment tbu if tbl has rolled over */
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if (now < gd->arch.tbl)
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gd->arch.tbu++;
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gd->arch.tbl = now;
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return (((unsigned long long)gd->arch.tbu) << 32) | gd->arch.tbl;
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}
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void __udelay(unsigned long usec)
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{
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unsigned long long start;
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ulong tmo;
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start = get_ticks(); /* get current timestamp */
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tmo = usec_to_tick(usec); /* convert usecs to ticks */
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while ((get_ticks() - start) < tmo)
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; /* loop till time has passed */
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}
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/*
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* get_timer(base) can be used to check for timeouts or
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* to measure elasped time relative to an event:
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*
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* ulong start_time = get_timer(0) sets start_time to the current
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* time value.
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* get_timer(start_time) returns the time elapsed since then.
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*
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* The time is used in CONFIG_SYS_HZ units!
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*/
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ulong get_timer(ulong base)
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{
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return tick_to_time(get_ticks()) - base;
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}
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/*
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* Return the number of timer ticks per second.
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*/
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ulong get_tbclk(void)
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{
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return gd->arch.timer_rate_hz;
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}
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