2 * (C) Copyright 2007-2008
3 * Stelian Pop <stelian@popies.net>
4 * Lead Tech Design <www.leadtechdesign.com>
6 * SPDX-License-Identifier: GPL-2.0+
11 #include <asm/arch/hardware.h>
12 #include <asm/arch/at91_pit.h>
13 #include <asm/arch/at91_pmc.h>
14 #include <asm/arch/clk.h>
17 #if !defined(CONFIG_AT91FAMILY)
18 # error You need to define CONFIG_AT91FAMILY in your board config!
21 DECLARE_GLOBAL_DATA_PTR;
24 * We're using the AT91CAP9/SAM9 PITC in 32 bit mode, by
25 * setting the 20 bit counter period to its maximum (0xfffff).
26 * (See the relevant data sheets to understand that this really works)
28 * We do also mimic the typical powerpc way of incrementing
29 * two 32 bit registers called tbl and tbu.
31 * Those registers increment at 1/16 the main clock rate.
34 #define TIMER_LOAD_VAL 0xfffff
36 static inline unsigned long long tick_to_time(unsigned long long tick)
38 tick *= CONFIG_SYS_HZ;
39 do_div(tick, gd->arch.timer_rate_hz);
44 static inline unsigned long long usec_to_tick(unsigned long long usec)
46 usec *= gd->arch.timer_rate_hz;
47 do_div(usec, 1000000);
53 * Use the PITC in full 32 bit incrementing mode
57 at91_pmc_t *pmc = (at91_pmc_t *) ATMEL_BASE_PMC;
58 at91_pit_t *pit = (at91_pit_t *) ATMEL_BASE_PIT;
60 /* Enable PITC Clock */
61 writel(1 << ATMEL_ID_SYS, &pmc->pcer);
64 writel(TIMER_LOAD_VAL | AT91_PIT_MR_EN , &pit->mr);
66 gd->arch.timer_rate_hz = gd->arch.mck_rate_hz / 16;
67 gd->arch.tbu = gd->arch.tbl = 0;
73 * Get the current 64 bit timer tick count
75 unsigned long long get_ticks(void)
77 at91_pit_t *pit = (at91_pit_t *) ATMEL_BASE_PIT;
79 ulong now = readl(&pit->piir);
81 /* increment tbu if tbl has rolled over */
82 if (now < gd->arch.tbl)
85 return (((unsigned long long)gd->arch.tbu) << 32) | gd->arch.tbl;
88 void __udelay(unsigned long usec)
90 unsigned long long start;
93 start = get_ticks(); /* get current timestamp */
94 tmo = usec_to_tick(usec); /* convert usecs to ticks */
95 while ((get_ticks() - start) < tmo)
96 ; /* loop till time has passed */
100 * get_timer(base) can be used to check for timeouts or
101 * to measure elasped time relative to an event:
103 * ulong start_time = get_timer(0) sets start_time to the current
105 * get_timer(start_time) returns the time elapsed since then.
107 * The time is used in CONFIG_SYS_HZ units!
109 ulong get_timer(ulong base)
111 return tick_to_time(get_ticks()) - base;
115 * Return the number of timer ticks per second.
117 ulong get_tbclk(void)
119 return gd->arch.timer_rate_hz;