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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/arm/mach-imx/time.c | |
download | lwn-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz lwn-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.zip |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'arch/arm/mach-imx/time.c')
-rw-r--r-- | arch/arm/mach-imx/time.c | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/arch/arm/mach-imx/time.c b/arch/arm/mach-imx/time.c new file mode 100644 index 000000000000..11f1e56c36bc --- /dev/null +++ b/arch/arm/mach-imx/time.c @@ -0,0 +1,101 @@ +/* + * linux/arch/arm/mach-imx/time.c + * + * Copyright (C) 2000-2001 Deep Blue Solutions + * Copyright (C) 2002 Shane Nay (shane@minirl.com) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ +#include <linux/config.h> +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/time.h> + +#include <asm/hardware.h> +#include <asm/io.h> +#include <asm/leds.h> +#include <asm/irq.h> +#include <asm/mach/time.h> + +/* Use timer 1 as system timer */ +#define TIMER_BASE IMX_TIM1_BASE + +/* + * Returns number of us since last clock interrupt. Note that interrupts + * will have been disabled by do_gettimeoffset() + */ +static unsigned long imx_gettimeoffset(void) +{ + unsigned long ticks; + + /* + * Get the current number of ticks. Note that there is a race + * condition between us reading the timer and checking for + * an interrupt. We get around this by ensuring that the + * counter has not reloaded between our two reads. + */ + ticks = IMX_TCN(TIMER_BASE); + + /* + * Interrupt pending? If so, we've reloaded once already. + */ + if (IMX_TSTAT(TIMER_BASE) & TSTAT_COMP) + ticks += LATCH; + + /* + * Convert the ticks to usecs + */ + return (1000000 / CLK32) * ticks; +} + +/* + * IRQ handler for the timer + */ +static irqreturn_t +imx_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs) +{ + write_seqlock(&xtime_lock); + + /* clear the interrupt */ + if (IMX_TSTAT(TIMER_BASE)) + IMX_TSTAT(TIMER_BASE) = 0; + + timer_tick(regs); + write_sequnlock(&xtime_lock); + + return IRQ_HANDLED; +} + +static struct irqaction imx_timer_irq = { + .name = "i.MX Timer Tick", + .flags = SA_INTERRUPT, + .handler = imx_timer_interrupt +}; + +/* + * Set up timer interrupt, and return the current time in seconds. + */ +static void __init imx_timer_init(void) +{ + /* + * Initialise to a known state (all timers off, and timing reset) + */ + IMX_TCTL(TIMER_BASE) = 0; + IMX_TPRER(TIMER_BASE) = 0; + IMX_TCMP(TIMER_BASE) = LATCH - 1; + IMX_TCTL(TIMER_BASE) = TCTL_CLK_32 | TCTL_IRQEN | TCTL_TEN; + + /* + * Make irqs happen for the system timer + */ + setup_irq(TIM1_INT, &imx_timer_irq); +} + +struct sys_timer imx_timer = { + .init = imx_timer_init, + .offset = imx_gettimeoffset, +}; |