diff options
Diffstat (limited to 'arch/m68k/platform/coldfire/timers.c')
| -rw-r--r-- | arch/m68k/platform/coldfire/timers.c | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/arch/m68k/platform/coldfire/timers.c b/arch/m68k/platform/coldfire/timers.c new file mode 100644 index 0000000..60242f6 --- /dev/null +++ b/arch/m68k/platform/coldfire/timers.c @@ -0,0 +1,174 @@ +/***************************************************************************/ + +/* + * timers.c -- generic ColdFire hardware timer support. + * + * Copyright (C) 1999-2008, Greg Ungerer <gerg@snapgear.com> + */ + +/***************************************************************************/ + +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/sched.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/profile.h> +#include <linux/clocksource.h> +#include <asm/io.h> +#include <asm/traps.h> +#include <asm/machdep.h> +#include <asm/coldfire.h> +#include <asm/mcftimer.h> +#include <asm/mcfsim.h> + +/***************************************************************************/ + +/* + * By default use timer1 as the system clock timer. + */ +#define FREQ (MCF_BUSCLK / 16) +#define TA(a) (MCFTIMER_BASE1 + (a)) + +/* + * These provide the underlying interrupt vector support. + * Unfortunately it is a little different on each ColdFire. + */ +void coldfire_profile_init(void); + +#if defined(CONFIG_M532x) +#define __raw_readtrr __raw_readl +#define __raw_writetrr __raw_writel +#else +#define __raw_readtrr __raw_readw +#define __raw_writetrr __raw_writew +#endif + +static u32 mcftmr_cycles_per_jiffy; +static u32 mcftmr_cnt; + +/***************************************************************************/ + +static irqreturn_t mcftmr_tick(int irq, void *dummy) +{ + /* Reset the ColdFire timer */ + __raw_writeb(MCFTIMER_TER_CAP | MCFTIMER_TER_REF, TA(MCFTIMER_TER)); + + mcftmr_cnt += mcftmr_cycles_per_jiffy; + return arch_timer_interrupt(irq, dummy); +} + +/***************************************************************************/ + +static struct irqaction mcftmr_timer_irq = { + .name = "timer", + .flags = IRQF_DISABLED | IRQF_TIMER, + .handler = mcftmr_tick, +}; + +/***************************************************************************/ + +static cycle_t mcftmr_read_clk(struct clocksource *cs) +{ + unsigned long flags; + u32 cycles; + u16 tcn; + + local_irq_save(flags); + tcn = __raw_readw(TA(MCFTIMER_TCN)); + cycles = mcftmr_cnt; + local_irq_restore(flags); + + return cycles + tcn; +} + +/***************************************************************************/ + +static struct clocksource mcftmr_clk = { + .name = "tmr", + .rating = 250, + .read = mcftmr_read_clk, + .shift = 20, + .mask = CLOCKSOURCE_MASK(32), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +/***************************************************************************/ + +void hw_timer_init(void) +{ + __raw_writew(MCFTIMER_TMR_DISABLE, TA(MCFTIMER_TMR)); + mcftmr_cycles_per_jiffy = FREQ / HZ; + /* + * The coldfire timer runs from 0 to TRR included, then 0 + * again and so on. It counts thus actually TRR + 1 steps + * for 1 tick, not TRR. So if you want n cycles, + * initialize TRR with n - 1. + */ + __raw_writetrr(mcftmr_cycles_per_jiffy - 1, TA(MCFTIMER_TRR)); + __raw_writew(MCFTIMER_TMR_ENORI | MCFTIMER_TMR_CLK16 | + MCFTIMER_TMR_RESTART | MCFTIMER_TMR_ENABLE, TA(MCFTIMER_TMR)); + + mcftmr_clk.mult = clocksource_hz2mult(FREQ, mcftmr_clk.shift); + clocksource_register(&mcftmr_clk); + + setup_irq(MCF_IRQ_TIMER, &mcftmr_timer_irq); + +#ifdef CONFIG_HIGHPROFILE + coldfire_profile_init(); +#endif +} + +/***************************************************************************/ +#ifdef CONFIG_HIGHPROFILE +/***************************************************************************/ + +/* + * By default use timer2 as the profiler clock timer. + */ +#define PA(a) (MCFTIMER_BASE2 + (a)) + +/* + * Choose a reasonably fast profile timer. Make it an odd value to + * try and get good coverage of kernel operations. + */ +#define PROFILEHZ 1013 + +/* + * Use the other timer to provide high accuracy profiling info. + */ +irqreturn_t coldfire_profile_tick(int irq, void *dummy) +{ + /* Reset ColdFire timer2 */ + __raw_writeb(MCFTIMER_TER_CAP | MCFTIMER_TER_REF, PA(MCFTIMER_TER)); + if (current->pid) + profile_tick(CPU_PROFILING); + return IRQ_HANDLED; +} + +/***************************************************************************/ + +static struct irqaction coldfire_profile_irq = { + .name = "profile timer", + .flags = IRQF_DISABLED | IRQF_TIMER, + .handler = coldfire_profile_tick, +}; + +void coldfire_profile_init(void) +{ + printk(KERN_INFO "PROFILE: lodging TIMER2 @ %dHz as profile timer\n", + PROFILEHZ); + + /* Set up TIMER 2 as high speed profile clock */ + __raw_writew(MCFTIMER_TMR_DISABLE, PA(MCFTIMER_TMR)); + + __raw_writetrr(((MCF_BUSCLK / 16) / PROFILEHZ), PA(MCFTIMER_TRR)); + __raw_writew(MCFTIMER_TMR_ENORI | MCFTIMER_TMR_CLK16 | + MCFTIMER_TMR_RESTART | MCFTIMER_TMR_ENABLE, PA(MCFTIMER_TMR)); + + setup_irq(MCF_IRQ_PROFILER, &coldfire_profile_irq); +} + +/***************************************************************************/ +#endif /* CONFIG_HIGHPROFILE */ +/***************************************************************************/ |
