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author | Peter Tyser <ptyser@xes-inc.com> | 2010-04-13 03:28:11 (GMT) |
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committer | Wolfgang Denk <wd@denx.de> | 2010-04-13 07:13:24 (GMT) |
commit | 84ad688473bec2875e171b71040eb9e033c6c206 (patch) | |
tree | cf181129cbdf5d833d55262f759ea2cd9cafaff7 /arch/arm/cpu/arm926ejs/nomadik/timer.c | |
parent | 8f0fec74ac6d0f3a7134ccebafa1ed9bd8c712ba (diff) | |
download | u-boot-84ad688473bec2875e171b71040eb9e033c6c206.tar.xz |
arm: Move cpu/$CPU to arch/arm/cpu/$CPU
Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
Diffstat (limited to 'arch/arm/cpu/arm926ejs/nomadik/timer.c')
-rw-r--r-- | arch/arm/cpu/arm926ejs/nomadik/timer.c | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/arch/arm/cpu/arm926ejs/nomadik/timer.c b/arch/arm/cpu/arm926ejs/nomadik/timer.c new file mode 100644 index 0000000..1d98ef3 --- /dev/null +++ b/arch/arm/cpu/arm926ejs/nomadik/timer.c @@ -0,0 +1,79 @@ +/* + * (C) Copyright 2009 Alessandro Rubini + * + * 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/mtu.h> + +/* + * The timer is a decrementer, we'll left it free running at 2.4MHz. + * We have 2.4 ticks per microsecond and an overflow in almost 30min + */ +#define TIMER_CLOCK (24 * 100 * 1000) +#define COUNT_TO_USEC(x) ((x) * 5 / 12) /* overflows at 6min */ +#define USEC_TO_COUNT(x) ((x) * 12 / 5) /* overflows at 6min */ +#define TICKS_PER_HZ (TIMER_CLOCK / CONFIG_SYS_HZ) +#define TICKS_TO_HZ(x) ((x) / TICKS_PER_HZ) + +/* macro to read the decrementing 32 bit timer as an increasing count */ +#define READ_TIMER() (0 - readl(CONFIG_SYS_TIMERBASE + MTU_VAL(0))) + +/* Configure a free-running, auto-wrap counter with no prescaler */ +int timer_init(void) +{ + writel(MTU_CRn_ENA | MTU_CRn_PRESCALE_1 | MTU_CRn_32BITS, + CONFIG_SYS_TIMERBASE + MTU_CR(0)); + reset_timer(); + return 0; +} + +/* Restart counting from 0 */ +void reset_timer(void) +{ + ulong val; + writel(0, CONFIG_SYS_TIMERBASE + MTU_LR(0)); + /* + * The load-register isn't really immediate: it changes on clock + * edges, so we must wait for our newly-written value to appear. + * Since we might miss reading 0, wait for any change in value. + */ + val = READ_TIMER(); + while (READ_TIMER() == val) + ; +} + +/* Return how many HZ passed since "base" */ +ulong get_timer(ulong base) +{ + return TICKS_TO_HZ(READ_TIMER()) - base; +} + +/* Delay x useconds */ +void __udelay(unsigned long usec) +{ + ulong ini, end; + + ini = READ_TIMER(); + end = ini + USEC_TO_COUNT(usec); + while ((signed)(end - READ_TIMER()) > 0) + ; +} |