X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=arch%2Farm%2Fcpu%2Farm1136%2Fmx35%2Ftimer.c;h=cc6166f938b4e04adb01a587c36bafc49bf73f7a;hb=254d68b6011c33af189d006243920c296592fca7;hp=db1e2c9d418dedaa340f25d7dd4aae54e00f5f2f;hpb=be9db564de898240034151c48cf9e0d03ece3f35;p=oweals%2Fu-boot.git diff --git a/arch/arm/cpu/arm1136/mx35/timer.c b/arch/arm/cpu/arm1136/mx35/timer.c index db1e2c9d41..cc6166f938 100644 --- a/arch/arm/cpu/arm1136/mx35/timer.c +++ b/arch/arm/cpu/arm1136/mx35/timer.c @@ -4,117 +4,127 @@ * * (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 + * SPDX-License-Identifier: GPL-2.0+ */ #include #include +#include #include +#include +#include + +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 (0x100<<6) /* Clock source */ -#define GPTCR_CLKSOURCE_IPG (0x001<<6) /* Clock source */ +#define GPTCR_CLKSOURCE_32 (4<<6) /* Clock source */ #define GPTCR_TEN (1) /* Timer enable */ -#define GPTPR_VAL (66) +/* + * "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); - for (i = 0; i < 100; i++) - writel(0, &gpt->ctrl); /* We have no udelay by now */ - writel(GPTPR_VAL, &gpt->pre); - /* Freerun Mode, PERCLK1 input */ - writel(readl(&gpt->ctrl) | - GPTCR_CLKSOURCE_IPG | GPTCR_TEN, - &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; } -void reset_timer_masked(void) +unsigned long long get_ticks(void) { struct gpt_regs *gpt = (struct gpt_regs *)GPT1_BASE_ADDR; - - writel(0, &gpt->ctrl); - /* Freerun Mode, PERCLK1 input */ - writel(GPTCR_CLKSOURCE_IPG | GPTCR_TEN, - &gpt->ctrl); + 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; } -inline ulong get_timer_masked(void) +ulong get_timer_masked(void) { - - struct gpt_regs *gpt = (struct gpt_regs *)GPT1_BASE_ADDR; - ulong val = readl(&gpt->counter); - - return val; + /* + * 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()); } -void reset_timer(void) +ulong get_timer(ulong base) { - reset_timer_masked(); + return get_timer_masked() - base; } -ulong get_timer(ulong base) +/* delay x useconds AND preserve advance timstamp value */ +void __udelay(unsigned long usec) { - ulong tmp; + unsigned long long tmp; + ulong tmo; - tmp = get_timer_masked(); + tmo = us_to_tick(usec); + tmp = get_ticks() + tmo; /* get current timestamp */ - if (tmp <= (base * 1000)) { - /* Overflow */ - tmp += (0xffffffff - base); - } - - return (tmp / 1000) - base; -} - -void set_timer(ulong t) -{ + while (get_ticks() < tmp) /* loop till event */ + /*NOP*/; } /* - * delay x useconds AND preserve advance timstamp value - * GPTCNT is now supposed to tick 1 by 1 us. + * This function is derived from PowerPC code (timebase clock frequency). + * On ARM it returns the number of timer ticks per second. */ -void __udelay(unsigned long usec) +ulong get_tbclk(void) { - ulong tmp; - - tmp = get_timer_masked(); /* get current timestamp */ - - /* if setting this forward will roll time stamp */ - if ((usec + tmp + 1) < tmp) { - /* reset "advancing" timestamp to 0, set lastinc value */ - reset_timer_masked(); - } else { - /* else, set advancing stamp wake up time */ - tmp += usec; - } - - while (get_timer_masked() < tmp) /* loop till event */ - /*NOP*/; + return MXC_CLK32; }