diff options
Diffstat (limited to 'arch/arm/imx-common/timer.c')
-rw-r--r-- | arch/arm/imx-common/timer.c | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/arch/arm/imx-common/timer.c b/arch/arm/imx-common/timer.c new file mode 100644 index 0000000..e2725e1 --- /dev/null +++ b/arch/arm/imx-common/timer.c @@ -0,0 +1,149 @@ +/* + * (C) Copyright 2007 + * Sascha Hauer, Pengutronix + * + * (C) Copyright 2009 Freescale Semiconductor, Inc. + * + * 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 <asm/io.h> +#include <div64.h> +#include <asm/arch/imx-regs.h> + +/* General purpose timers registers */ +struct mxc_gpt { + unsigned int control; + unsigned int prescaler; + unsigned int status; + unsigned int nouse[6]; + unsigned int counter; +}; + +static struct mxc_gpt *cur_gpt = (struct mxc_gpt *)GPT1_BASE_ADDR; + +/* General purpose timers bitfields */ +#define GPTCR_SWR (1 << 15) /* Software reset */ +#define GPTCR_FRR (1 << 9) /* Freerun / restart */ +#define GPTCR_CLKSOURCE_32 (4 << 6) /* Clock source */ +#define GPTCR_TEN 1 /* Timer enable */ +#define CLK_32KHZ 32768 /* 32Khz input */ + +DECLARE_GLOBAL_DATA_PTR; + +#define timestamp (gd->tbl) +#define lastinc (gd->lastinc) + +static inline unsigned long long tick_to_time(unsigned long long tick) +{ + tick *= CONFIG_SYS_HZ; + do_div(tick, CLK_32KHZ); + + return tick; +} + +static inline unsigned long long us_to_tick(unsigned long long usec) +{ + usec = usec * CLK_32KHZ + 999999; + do_div(usec, 1000000); + + return usec; +} + +int timer_init(void) +{ + int i; + ulong val; + + /* setup GP Timer 1 */ + __raw_writel(GPTCR_SWR, &cur_gpt->control); + + /* We have no udelay by now */ + for (i = 0; i < 100; i++) + __raw_writel(0, &cur_gpt->control); + + __raw_writel(0, &cur_gpt->prescaler); /* 32Khz */ + + /* Freerun Mode, PERCLK1 input */ + i = __raw_readl(&cur_gpt->control); + __raw_writel(i | GPTCR_CLKSOURCE_32 | GPTCR_TEN, &cur_gpt->control); + + val = __raw_readl(&cur_gpt->counter); + lastinc = val / (CLK_32KHZ / CONFIG_SYS_HZ); + timestamp = 0; + + return 0; +} + +unsigned long long get_ticks(void) +{ + ulong now = __raw_readl(&cur_gpt->counter); /* 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_MX25_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; +} + +/* delay x useconds AND preserve 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*/; +} + +/* + * This function is derived from PowerPC code (timebase clock frequency). + * On ARM it returns the number of timer ticks per second. + */ +ulong get_tbclk(void) +{ + return CLK_32KHZ; +} |