diff options
Diffstat (limited to 'arch/arm/cpu/arm1136/mx35/timer.c')
-rw-r--r-- | arch/arm/cpu/arm1136/mx35/timer.c | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/arch/arm/cpu/arm1136/mx35/timer.c b/arch/arm/cpu/arm1136/mx35/timer.c new file mode 100644 index 0000000..584ad15 --- /dev/null +++ b/arch/arm/cpu/arm1136/mx35/timer.c @@ -0,0 +1,146 @@ +/* + * (C) Copyright 2007 + * Sascha Hauer, Pengutronix + * + * (C) Copyright 2008-2009 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> +#include <asm/arch/crm_regs.h> +#include <asm/arch/clock.h> + +DECLARE_GLOBAL_DATA_PTR; + +#define timestamp (gd->arch.tbl) +#define lastinc (gd->arch.lastinc) + +/* 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 */ + +/* + * "time" is measured in 1 / CONFIG_SYS_HZ seconds, + * "tick" is internal timer period + */ +/* ~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, MXC_CLK32); + + return tick; +} + +static inline unsigned long long us_to_tick(unsigned long long us) +{ + us = us * MXC_CLK32 + 999999; + do_div(us, 1000000); + + return us; +} + +/* + * nothing really to do with interrupts, just starts up a counter. + * The 32KHz 32-bit timer overruns in 134217 seconds + */ +int timer_init(void) +{ + int i; + struct gpt_regs *gpt = (struct gpt_regs *)GPT1_BASE_ADDR; + struct ccm_regs *ccm = (struct ccm_regs *)CCM_BASE_ADDR; + + /* setup GP Timer 1 */ + writel(GPTCR_SWR, &gpt->ctrl); + + writel(readl(&ccm->cgr1) | 3 << MXC_CCM_CGR1_GPT_OFFSET, &ccm->cgr1); + + for (i = 0; i < 100; i++) + writel(0, &gpt->ctrl); /* We have no udelay by now */ + writel(0, &gpt->pre); /* prescaler = 1 */ + /* Freerun Mode, 32KHz input */ + writel(readl(&gpt->ctrl) | GPTCR_CLKSOURCE_32 | GPTCR_FRR, + &gpt->ctrl); + writel(readl(&gpt->ctrl) | GPTCR_TEN, &gpt->ctrl); + + return 0; +} + +unsigned long long get_ticks(void) +{ + struct gpt_regs *gpt = (struct gpt_regs *)GPT1_BASE_ADDR; + ulong now = readl(&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 / MXC_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 MXC_CLK32; +} |