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Diffstat (limited to 'cpu/arm926ejs/mx27/timer.c')
| -rw-r--r-- | cpu/arm926ejs/mx27/timer.c | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/cpu/arm926ejs/mx27/timer.c b/cpu/arm926ejs/mx27/timer.c new file mode 100644 index 0000000..d22252e --- /dev/null +++ b/cpu/arm926ejs/mx27/timer.c @@ -0,0 +1,191 @@ +/* + * (C) Copyright 2002 + * Sysgo Real-Time Solutions, GmbH <www.elinos.com> + * Marius Groeger <mgroeger@sysgo.de> + * + * (C) Copyright 2002 + * Sysgo Real-Time Solutions, GmbH <www.elinos.com> + * Alex Zuepke <azu@sysgo.de> + * + * (C) Copyright 2002 + * Gary Jennejohn, DENX Software Engineering, <gj@denx.de> + * + * (C) Copyright 2009 + * Ilya Yanok, Emcraft Systems Ltd, <yanok@emcraft.com> + * + * See file CREDITS for list of people who contributed to this + * project. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ + +#include <common.h> +#include <div64.h> +#include <asm/io.h> +#include <asm/arch/imx-regs.h> + +/* General purpose timers bitfields */ +#define GPTCR_SWR (1 << 15) /* Software reset */ +#define GPTCR_FRR (1 << 8) /* Freerun / restart */ +#define GPTCR_CLKSOURCE_32 (4 << 1) /* Clock source */ +#define GPTCR_TEN 1 /* Timer enable */ + +static ulong timestamp; +static ulong lastinc; + +/* + * "time" is measured in 1 / CONFIG_SYS_HZ seconds, + * "tick" is internal timer period + */ +#ifdef CONFIG_MX27_TIMER_HIGH_PRECISION +/* ~0.4% error - measured with stop-watch on 100s boot-delay */ +static inline unsigned long long tick_to_time(unsigned long long tick) +{ + tick *= CONFIG_SYS_HZ; + do_div(tick, CONFIG_MX27_CLK32); + return tick; +} + +static inline unsigned long long time_to_tick(unsigned long long time) +{ + time *= CONFIG_MX27_CLK32; + do_div(time, CONFIG_SYS_HZ); + return time; +} + +static inline unsigned long long us_to_tick(unsigned long long us) +{ + us = us * CONFIG_MX27_CLK32 + 999999; + do_div(us, 1000000); + return us; +} +#else +/* ~2% error */ +#define TICK_PER_TIME ((CONFIG_MX27_CLK32 + CONFIG_SYS_HZ / 2) / \ + CONFIG_SYS_HZ) +#define US_PER_TICK (1000000 / CONFIG_MX27_CLK32) + +static inline unsigned long long tick_to_time(unsigned long long tick) +{ + do_div(tick, TICK_PER_TIME); + return tick; +} + +static inline unsigned long long time_to_tick(unsigned long long time) +{ + return time * TICK_PER_TIME; +} + +static inline unsigned long long us_to_tick(unsigned long long us) +{ + us += US_PER_TICK - 1; + do_div(us, US_PER_TICK); + return us; +} +#endif + +/* nothing really to do with interrupts, just starts up a counter. */ +/* The 32768Hz 32-bit timer overruns in 131072 seconds */ +int timer_init(void) +{ + int i; + struct gpt_regs *regs = (struct gpt_regs *)IMX_TIM1_BASE; + struct pll_regs *pll = (struct pll_regs *)IMX_PLL_BASE; + + /* setup GP Timer 1 */ + writel(GPTCR_SWR, ®s->gpt_tctl); + + writel(readl(&pll->pccr0) | PCCR0_GPT1_EN, &pll->pccr0); + writel(readl(&pll->pccr1) | PCCR1_PERCLK1_EN, &pll->pccr1); + + for (i = 0; i < 100; i++) + writel(0, ®s->gpt_tctl); /* We have no udelay by now */ + writel(0, ®s->gpt_tprer); /* 32Khz */ + /* Freerun Mode, PERCLK1 input */ + writel(readl(®s->gpt_tctl) | GPTCR_CLKSOURCE_32 | GPTCR_FRR, + ®s->gpt_tctl); + writel(readl(®s->gpt_tctl) | GPTCR_TEN, ®s->gpt_tctl); + + return 0; +} + +void reset_timer_masked(void) +{ + struct gpt_regs *regs = (struct gpt_regs *)IMX_TIM1_BASE; + /* reset time */ + /* capture current incrementer value time */ + lastinc = readl(®s->gpt_tcn); + timestamp = 0; /* start "advancing" time stamp from 0 */ +} + +void reset_timer(void) +{ + reset_timer_masked(); +} + +unsigned long long get_ticks (void) +{ + struct gpt_regs *regs = (struct gpt_regs *)IMX_TIM1_BASE; + ulong now = readl(®s->gpt_tcn); /* current tick value */ + + if (now >= lastinc) { + /* + * normal mode (non roll) + * move stamp forward with absolut diff ticks + */ + timestamp += (now - lastinc); + } else { + /* we have rollover of incrementer */ + timestamp += (0xFFFFFFFF - lastinc) + now; + } + lastinc = now; + return timestamp; +} + +ulong get_timer_masked (void) +{ + /* + * get_ticks() returns a long long (64 bit), it wraps in + * 2^64 / CONFIG_MX27_CLK32 = 2^64 / 2^15 = 2^49 ~ 5 * 10^14 (s) ~ + * 5 * 10^9 days... and get_ticks() * CONFIG_SYS_HZ wraps in + * 5 * 10^6 days - long enough. + */ + return tick_to_time(get_ticks()); +} + +ulong get_timer (ulong base) +{ + return get_timer_masked () - base; +} + +void set_timer (ulong t) +{ + timestamp = time_to_tick(t); +} + +/* delay x useconds AND perserve advance timstamp value */ +void udelay (unsigned long usec) +{ + unsigned long long tmp; + ulong tmo; + + tmo = us_to_tick(usec); + tmp = get_ticks() + tmo; /* get current timestamp */ + + while (get_ticks() < tmp) /* loop till event */ + /*NOP*/; +} + |