2 * (C) Copyright 2007-2008
3 * Stelian Pop <stelian.pop@leadtechdesign.com>
4 * Lead Tech Design <www.leadtechdesign.com>
6 * See file CREDITS for list of people who contributed to this
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License as
11 * published by the Free Software Foundation; either version 2 of
12 * the License, or (at your option) any later version.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
26 #include <asm/arch/hardware.h>
27 #include <asm/arch/at91_pit.h>
28 #include <asm/arch/at91_pmc.h>
29 #include <asm/arch/clk.h>
30 #include <asm/arch/io.h>
34 * We're using the AT91CAP9/SAM9 PITC in 32 bit mode, by
35 * setting the 20 bit counter period to its maximum (0xfffff).
37 #define TIMER_LOAD_VAL 0xfffff
39 static ulong timestamp;
41 static ulong timer_freq;
43 static inline unsigned long long tick_to_time(unsigned long long tick)
45 tick *= CONFIG_SYS_HZ;
46 do_div(tick, timer_freq);
51 static inline unsigned long long usec_to_tick(unsigned long long usec)
54 do_div(usec, 1000000);
59 /* nothing really to do with interrupts, just starts up a counter. */
62 at91_pmc_t *pmc = (at91_pmc_t *) AT91_PMC_BASE;
63 at91_pit_t *pit = (at91_pit_t *) AT91_PIT_BASE;
66 * The clock is already enabled for system controller in boot
68 writel(1 << AT91_ID_SYS, &pmc->pcer);
71 writel(TIMER_LOAD_VAL | AT91_PIT_MR_EN , &pit->mr);
75 timer_freq = get_mck_clk_rate() >> 4;
81 * timer without interrupts
83 unsigned long long get_ticks(void)
85 at91_pit_t *pit = (at91_pit_t *) AT91_PIT_BASE;
87 ulong now = readl(&pit->piir);
89 if (now >= lastinc) /* normal mode (non roll) */
90 /* move stamp forward with absolut diff ticks */
91 timestamp += (now - lastinc);
92 else /* we have rollover of incrementer */
93 timestamp += (0xFFFFFFFF - lastinc) + now;
98 void reset_timer_masked(void)
101 at91_pit_t *pit = (at91_pit_t *) AT91_PIT_BASE;
103 /* capture current incrementer value time */
104 lastinc = readl(&pit->piir);
105 timestamp = 0; /* start "advancing" time stamp from 0 */
108 ulong get_timer_masked(void)
110 return tick_to_time(get_ticks());
113 void __udelay(unsigned long usec)
115 unsigned long long tmp;
118 tmo = usec_to_tick(usec);
119 tmp = get_ticks() + tmo; /* get current timestamp */
121 while (get_ticks() < tmp) /* loop till event */
125 void reset_timer(void)
127 reset_timer_masked();
130 ulong get_timer(ulong base)
132 return get_timer_masked () - base;
136 * This function is derived from PowerPC code (timebase clock frequency).
137 * On ARM it returns the number of timer ticks per second.
139 ulong get_tbclk(void)