diff options
Diffstat (limited to 'arch/arm/cpu/armv7/u8500/timer.c')
| -rw-r--r-- | arch/arm/cpu/armv7/u8500/timer.c | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/arch/arm/cpu/armv7/u8500/timer.c b/arch/arm/cpu/armv7/u8500/timer.c new file mode 100644 index 0000000..8e96eaa --- /dev/null +++ b/arch/arm/cpu/armv7/u8500/timer.c @@ -0,0 +1,154 @@ +/* + * Copyright (C) 2010 Linaro Limited + * John Rigby <john.rigby@linaro.org> + * + * Based on original from Linux kernel source and + * internal ST-Ericsson U-Boot source. + * (C) Copyright 2009 Alessandro Rubini + * (C) Copyright 2010 ST-Ericsson + * + * 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 <asm/arch/hardware.h> + +DECLARE_GLOBAL_DATA_PTR; + +/* + * The MTU device has some interrupt control registers + * followed by 4 timers. + */ + +/* The timers */ +struct u8500_mtu_timer { + u32 lr; /* Load value */ + u32 cv; /* Current value */ + u32 cr; /* Control reg */ + u32 bglr; /* ??? */ +}; + +/* The MTU that contains the timers */ +struct u8500_mtu { + u32 imsc; /* Interrupt mask set/clear */ + u32 ris; /* Raw interrupt status */ + u32 mis; /* Masked interrupt status */ + u32 icr; /* Interrupt clear register */ + struct u8500_mtu_timer pt[4]; +}; + +/* bits for the control register */ +#define MTU_CR_ONESHOT 0x01 /* if 0 = wraps reloading from BGLR */ +#define MTU_CR_32BITS 0x02 + +#define MTU_CR_PRESCALE_1 0x00 +#define MTU_CR_PRESCALE_16 0x04 +#define MTU_CR_PRESCALE_256 0x08 +#define MTU_CR_PRESCALE_MASK 0x0c + +#define MTU_CR_PERIODIC 0x40 /* if 0 = free-running */ +#define MTU_CR_ENA 0x80 + +/* + * The MTU is clocked at 133 MHz by default. (V1 and later) + */ +#define TIMER_CLOCK (133 * 1000 * 1000 / 16) +#define COUNT_TO_USEC(x) ((x) * 16 / 133) +#define USEC_TO_COUNT(x) ((x) * 133 / 16) +#define TICKS_PER_HZ (TIMER_CLOCK / CONFIG_SYS_HZ) +#define TICKS_TO_HZ(x) ((x) / TICKS_PER_HZ) +#define TIMER_LOAD_VAL 0xffffffff + +/* + * MTU timer to use (from 0 to 3). + */ +#define MTU_TIMER 2 + +static struct u8500_mtu_timer *timer_base = + &((struct u8500_mtu *)U8500_MTU0_BASE_V1)->pt[MTU_TIMER]; + +/* macro to read the 32 bit timer: since it decrements, we invert read value */ +#define READ_TIMER() (~readl(&timer_base->cv)) + +/* Configure a free-running, auto-wrap counter with /16 prescaler */ +int timer_init(void) +{ + writel(MTU_CR_ENA | MTU_CR_PRESCALE_16 | MTU_CR_32BITS, + &timer_base->cr); + return 0; +} + +ulong get_timer_masked(void) +{ + /* current tick value */ + ulong now = TICKS_TO_HZ(READ_TIMER()); + + if (now >= gd->lastinc) /* normal (non rollover) */ + gd->tbl += (now - gd->lastinc); + else /* rollover */ + gd->tbl += (TICKS_TO_HZ(TIMER_LOAD_VAL) - gd->lastinc) + now; + gd->lastinc = now; + return gd->tbl; +} + +/* Delay x useconds */ +void __udelay(ulong usec) +{ + long tmo = usec * (TIMER_CLOCK / 1000) / 1000; + ulong now, last = READ_TIMER(); + + while (tmo > 0) { + now = READ_TIMER(); + if (now > last) /* normal (non rollover) */ + tmo -= now - last; + else /* rollover */ + tmo -= TIMER_LOAD_VAL - last + now; + last = now; + } +} + +ulong get_timer(ulong base) +{ + return get_timer_masked() - base; +} + +void set_timer(ulong t) +{ + gd->tbl = t; +} + +/* + * Emulation of Power architecture long long timebase. + * + * TODO: Support gd->tbu for real long long timebase. + */ +unsigned long long get_ticks(void) +{ + return get_timer(0); +} + +/* + * Emulation of Power architecture timebase. + * NB: Low resolution compared to Power tbclk. + */ +ulong get_tbclk(void) +{ + return CONFIG_SYS_HZ; +} |