diff options
Diffstat (limited to 'arch/avr32/kernel')
| -rw-r--r-- | arch/avr32/kernel/time.c | 150 |
1 files changed, 77 insertions, 73 deletions
diff --git a/arch/avr32/kernel/time.c b/arch/avr32/kernel/time.c index c10833f2ee0..7014a3571ec 100644 --- a/arch/avr32/kernel/time.c +++ b/arch/avr32/kernel/time.c @@ -1,5 +1,5 @@ /* - * Copyright (C) 2004-2006 Atmel Corporation + * Copyright (C) 2004-2007 Atmel Corporation * * Based on MIPS implementation arch/mips/kernel/time.c * Copyright 2001 MontaVista Software Inc. @@ -20,18 +20,25 @@ #include <linux/init.h> #include <linux/profile.h> #include <linux/sysdev.h> +#include <linux/err.h> #include <asm/div64.h> #include <asm/sysreg.h> #include <asm/io.h> #include <asm/sections.h> -static cycle_t read_cycle_count(void) +/* how many counter cycles in a jiffy? */ +static u32 cycles_per_jiffy; + +/* the count value for the next timer interrupt */ +static u32 expirelo; + +cycle_t __weak read_cycle_count(void) { return (cycle_t)sysreg_read(COUNT); } -static struct clocksource clocksource_avr32 = { +struct clocksource __weak clocksource_avr32 = { .name = "avr32", .rating = 350, .read = read_cycle_count, @@ -40,12 +47,20 @@ static struct clocksource clocksource_avr32 = { .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; +irqreturn_t __weak timer_interrupt(int irq, void *dev_id); + +struct irqaction timer_irqaction = { + .handler = timer_interrupt, + .flags = IRQF_DISABLED, + .name = "timer", +}; + /* * By default we provide the null RTC ops */ static unsigned long null_rtc_get_time(void) { - return mktime(2004, 1, 1, 0, 0, 0); + return mktime(2007, 1, 1, 0, 0, 0); } static int null_rtc_set_time(unsigned long sec) @@ -56,23 +71,14 @@ static int null_rtc_set_time(unsigned long sec) static unsigned long (*rtc_get_time)(void) = null_rtc_get_time; static int (*rtc_set_time)(unsigned long) = null_rtc_set_time; -/* how many counter cycles in a jiffy? */ -static unsigned long cycles_per_jiffy; - -/* cycle counter value at the previous timer interrupt */ -static unsigned int timerhi, timerlo; - -/* the count value for the next timer interrupt */ -static unsigned int expirelo; - static void avr32_timer_ack(void) { - unsigned int count; + u32 count; /* Ack this timer interrupt and set the next one */ expirelo += cycles_per_jiffy; + /* setting COMPARE to 0 stops the COUNT-COMPARE */ if (expirelo == 0) { - printk(KERN_DEBUG "expirelo == 0\n"); sysreg_write(COMPARE, expirelo + 1); } else { sysreg_write(COMPARE, expirelo); @@ -86,27 +92,56 @@ static void avr32_timer_ack(void) } } -static unsigned int avr32_hpt_read(void) +int __weak avr32_hpt_init(void) { - return sysreg_read(COUNT); + int ret; + unsigned long mult, shift, count_hz; + + count_hz = clk_get_rate(boot_cpu_data.clk); + shift = clocksource_avr32.shift; + mult = clocksource_hz2mult(count_hz, shift); + clocksource_avr32.mult = mult; + + { + u64 tmp; + + tmp = TICK_NSEC; + tmp <<= shift; + tmp += mult / 2; + do_div(tmp, mult); + + cycles_per_jiffy = tmp; + } + + ret = setup_irq(0, &timer_irqaction); + if (ret) { + pr_debug("timer: could not request IRQ 0: %d\n", ret); + return -ENODEV; + } + + printk(KERN_INFO "timer: AT32AP COUNT-COMPARE at irq 0, " + "%lu.%03lu MHz\n", + ((count_hz + 500) / 1000) / 1000, + ((count_hz + 500) / 1000) % 1000); + + return 0; } /* * Taken from MIPS c0_hpt_timer_init(). * - * Why is it so complicated, and what is "count"? My assumption is - * that `count' specifies the "reference cycle", i.e. the cycle since - * reset that should mean "zero". The reason COUNT is written twice is - * probably to make sure we don't get any timer interrupts while we - * are messing with the counter. + * The reason COUNT is written twice is probably to make sure we don't get any + * timer interrupts while we are messing with the counter. */ -static void avr32_hpt_init(unsigned int count) +int __weak avr32_hpt_start(void) { - count = sysreg_read(COUNT) - count; + u32 count = sysreg_read(COUNT); expirelo = (count / cycles_per_jiffy + 1) * cycles_per_jiffy; sysreg_write(COUNT, expirelo - cycles_per_jiffy); sysreg_write(COMPARE, expirelo); sysreg_write(COUNT, count); + + return 0; } /* @@ -115,26 +150,18 @@ static void avr32_hpt_init(unsigned int count) * * In UP mode, it is invoked from the (global) timer_interrupt. */ -static void local_timer_interrupt(int irq, void *dev_id) +void local_timer_interrupt(int irq, void *dev_id) { if (current->pid) profile_tick(CPU_PROFILING); update_process_times(user_mode(get_irq_regs())); } -static irqreturn_t -timer_interrupt(int irq, void *dev_id) +irqreturn_t __weak timer_interrupt(int irq, void *dev_id) { - unsigned int count; - /* ack timer interrupt and try to set next interrupt */ - count = avr32_hpt_read(); avr32_timer_ack(); - /* Update timerhi/timerlo for intra-jiffy calibration */ - timerhi += count < timerlo; /* Wrap around */ - timerlo = count; - /* * Call the generic timer interrupt handler */ @@ -153,60 +180,37 @@ timer_interrupt(int irq, void *dev_id) return IRQ_HANDLED; } -static struct irqaction timer_irqaction = { - .handler = timer_interrupt, - .flags = IRQF_DISABLED, - .name = "timer", -}; - void __init time_init(void) { - unsigned long mult, shift, count_hz; int ret; + /* + * Make sure we don't get any COMPARE interrupts before we can + * handle them. + */ + sysreg_write(COMPARE, 0); + xtime.tv_sec = rtc_get_time(); xtime.tv_nsec = 0; set_normalized_timespec(&wall_to_monotonic, -xtime.tv_sec, -xtime.tv_nsec); - printk("Before time_init: count=%08lx, compare=%08lx\n", - (unsigned long)sysreg_read(COUNT), - (unsigned long)sysreg_read(COMPARE)); - - count_hz = clk_get_rate(boot_cpu_data.clk); - shift = clocksource_avr32.shift; - mult = clocksource_hz2mult(count_hz, shift); - clocksource_avr32.mult = mult; - - printk("Cycle counter: mult=%lu, shift=%lu\n", mult, shift); - - { - u64 tmp; - - tmp = TICK_NSEC; - tmp <<= shift; - tmp += mult / 2; - do_div(tmp, mult); - - cycles_per_jiffy = tmp; + ret = avr32_hpt_init(); + if (ret) { + pr_debug("timer: failed setup: %d\n", ret); + return; } - /* This sets up the high precision timer for the first interrupt. */ - avr32_hpt_init(avr32_hpt_read()); - - printk("After time_init: count=%08lx, compare=%08lx\n", - (unsigned long)sysreg_read(COUNT), - (unsigned long)sysreg_read(COMPARE)); - ret = clocksource_register(&clocksource_avr32); if (ret) - printk(KERN_ERR - "timer: could not register clocksource: %d\n", ret); + pr_debug("timer: could not register clocksource: %d\n", ret); - ret = setup_irq(0, &timer_irqaction); - if (ret) - printk("timer: could not request IRQ 0: %d\n", ret); + ret = avr32_hpt_start(); + if (ret) { + pr_debug("timer: failed starting: %d\n", ret); + return; + } } static struct sysdev_class timer_class = { |