diff options
| -rw-r--r-- | arch/blackfin/Kconfig | 28 | ||||
| -rw-r--r-- | arch/blackfin/kernel/Makefile | 8 | ||||
| -rw-r--r-- | arch/blackfin/kernel/process.c | 43 | ||||
| -rw-r--r-- | arch/blackfin/kernel/time-ts.c | 194 |
4 files changed, 253 insertions, 20 deletions
diff --git a/arch/blackfin/Kconfig b/arch/blackfin/Kconfig index 2dd1f300a5cf..a3cf9d0a528b 100644 --- a/arch/blackfin/Kconfig +++ b/arch/blackfin/Kconfig @@ -47,10 +47,6 @@ config GENERIC_IRQ_PROBE bool default y -config GENERIC_TIME - bool - default n - config GENERIC_GPIO bool default y @@ -415,6 +411,30 @@ comment "Kernel Timer/Scheduler" source kernel/Kconfig.hz +config GENERIC_TIME + bool "Generic time" + default y + +config GENERIC_CLOCKEVENTS + bool "Generic clock events" + depends on GENERIC_TIME + default y + +config CYCLES_CLOCKSOURCE + bool "Use 'CYCLES' as a clocksource (EXPERIMENTAL)" + depends on EXPERIMENTAL + depends on GENERIC_CLOCKEVENTS + depends on !BFIN_SCRATCH_REG_CYCLES + default n + help + If you say Y here, you will enable support for using the 'cycles' + registers as a clock source. Doing so means you will be unable to + safely write to the 'cycles' register during runtime. You will + still be able to read it (such as for performance monitoring), but + writing the registers will most likely crash the kernel. + +source kernel/time/Kconfig + comment "Memory Setup" config MEM_SIZE diff --git a/arch/blackfin/kernel/Makefile b/arch/blackfin/kernel/Makefile index 318b9b692a48..6140cd69c782 100644 --- a/arch/blackfin/kernel/Makefile +++ b/arch/blackfin/kernel/Makefile @@ -6,9 +6,15 @@ extra-y := init_task.o vmlinux.lds obj-y := \ entry.o process.o bfin_ksyms.o ptrace.o setup.o signal.o \ - sys_bfin.o time.o traps.o irqchip.o dma-mapping.o flat.o \ + sys_bfin.o traps.o irqchip.o dma-mapping.o flat.o \ fixed_code.o reboot.o bfin_gpio.o +ifeq ($(CONFIG_GENERIC_CLOCKEVENTS),y) + obj-y += time-ts.o +else + obj-y += time.o +endif + obj-$(CONFIG_BFIN_GPTIMERS) += gptimers.o obj-$(CONFIG_MODULES) += module.o obj-$(CONFIG_BFIN_DMA_5XX) += bfin_dma_5xx.o diff --git a/arch/blackfin/kernel/process.c b/arch/blackfin/kernel/process.c index 6b8459c66163..6dedb2da8b67 100644 --- a/arch/blackfin/kernel/process.c +++ b/arch/blackfin/kernel/process.c @@ -32,6 +32,8 @@ #include <linux/unistd.h> #include <linux/user.h> #include <linux/uaccess.h> +#include <linux/sched.h> +#include <linux/tick.h> #include <linux/fs.h> #include <linux/err.h> @@ -69,33 +71,44 @@ EXPORT_SYMBOL(pm_power_off); * The idle loop on BFIN */ #ifdef CONFIG_IDLE_L1 -void default_idle(void)__attribute__((l1_text)); +static void default_idle(void)__attribute__((l1_text)); void cpu_idle(void)__attribute__((l1_text)); #endif -void default_idle(void) +/* + * This is our default idle handler. We need to disable + * interrupts here to ensure we don't miss a wakeup call. + */ +static void default_idle(void) { - while (!need_resched()) { - local_irq_disable(); - if (likely(!need_resched())) - idle_with_irq_disabled(); - local_irq_enable(); - } -} + local_irq_disable(); + if (!need_resched()) + idle_with_irq_disabled(); -void (*idle)(void) = default_idle; + local_irq_enable(); +} /* - * The idle thread. There's no useful work to be - * done, so just try to conserve power and have a - * low exit latency (ie sit in a loop waiting for - * somebody to say that they'd like to reschedule) + * The idle thread. We try to conserve power, while trying to keep + * overall latency low. The architecture specific idle is passed + * a value to indicate the level of "idleness" of the system. */ void cpu_idle(void) { /* endless idle loop with no priority at all */ while (1) { - idle(); + void (*idle)(void) = pm_idle; + +#ifdef CONFIG_HOTPLUG_CPU + if (cpu_is_offline(smp_processor_id())) + cpu_die(); +#endif + if (!idle) + idle = default_idle; + tick_nohz_stop_sched_tick(); + while (!need_resched()) + idle(); + tick_nohz_restart_sched_tick(); preempt_enable_no_resched(); schedule(); preempt_disable(); diff --git a/arch/blackfin/kernel/time-ts.c b/arch/blackfin/kernel/time-ts.c new file mode 100644 index 000000000000..3aad6d710726 --- /dev/null +++ b/arch/blackfin/kernel/time-ts.c @@ -0,0 +1,194 @@ +/* + * linux/arch/kernel/time-ts.c + * + * Based on arm clockevents implementation and old bfin time tick. + * + * Copyright(C) 2008, GeoTechnologies, Vitja Makarov + * + * This code is licenced under the GPL version 2. For details see + * kernel-base/COPYING. + */ +#include <linux/module.h> +#include <linux/profile.h> +#include <linux/interrupt.h> +#include <linux/time.h> +#include <linux/irq.h> +#include <linux/clocksource.h> +#include <linux/clockchips.h> + +#include <asm/blackfin.h> + +#ifdef CONFIG_CYCLES_CLOCKSOURCE + +static unsigned long cyc2ns_scale; +#define CYC2NS_SCALE_FACTOR 10 /* 2^10, carefully chosen */ + +static inline void set_cyc2ns_scale(unsigned long cpu_khz) +{ + cyc2ns_scale = (1000000 << CYC2NS_SCALE_FACTOR) / cpu_khz; +} + +static inline unsigned long long cycles_2_ns(cycle_t cyc) +{ + return (cyc * cyc2ns_scale) >> CYC2NS_SCALE_FACTOR; +} + +static cycle_t read_cycles(void) +{ + unsigned long tmp, tmp2; + asm("%0 = cycles; %1 = cycles2;" : "=d"(tmp), "=d"(tmp2)); + return tmp | ((cycle_t)tmp2 << 32); +} + +unsigned long long sched_clock(void) +{ + return cycles_2_ns(read_cycles()); +} + +static struct clocksource clocksource_bfin = { + .name = "bfin_cycles", + .rating = 350, + .read = read_cycles, + .mask = CLOCKSOURCE_MASK(64), + .shift = 22, + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +static int __init bfin_clocksource_init(void) +{ + set_cyc2ns_scale(get_cclk() / 1000); + + clocksource_bfin.mult = clocksource_hz2mult(get_cclk(), clocksource_bfin.shift); + + if (clocksource_register(&clocksource_bfin)) + panic("failed to register clocksource"); + + return 0; +} + +#else +# define bfin_clocksource_init() +#endif + +static int bfin_timer_set_next_event(unsigned long cycles, + struct clock_event_device *evt) +{ + bfin_write_TCOUNT(cycles); + CSYNC(); + return 0; +} + +static void bfin_timer_set_mode(enum clock_event_mode mode, + struct clock_event_device *evt) +{ + switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: { + unsigned long tcount = ((get_cclk() / (HZ * 1)) - 1); + bfin_write_TCNTL(TMPWR); + CSYNC(); + bfin_write_TPERIOD(tcount); + bfin_write_TCOUNT(tcount); + bfin_write_TCNTL(TMPWR | TMREN | TAUTORLD); + CSYNC(); + break; + } + case CLOCK_EVT_MODE_ONESHOT: + bfin_write_TCOUNT(0); + bfin_write_TCNTL(TMPWR | TMREN); + CSYNC(); + break; + case CLOCK_EVT_MODE_UNUSED: + case CLOCK_EVT_MODE_SHUTDOWN: + bfin_write_TCNTL(0); + CSYNC(); + break; + case CLOCK_EVT_MODE_RESUME: + break; + } +} + +static void __init bfin_timer_init(void) +{ + /* power up the timer, but don't enable it just yet */ + bfin_write_TCNTL(TMPWR); + CSYNC(); + + /* + * the TSCALE prescaler counter. + */ + bfin_write_TSCALE(0); + bfin_write_TPERIOD(0); + bfin_write_TCOUNT(0); + + /* now enable the timer */ + CSYNC(); +} + +/* + * timer_interrupt() needs to keep up the real-time clock, + * as well as call the "do_timer()" routine every clocktick + */ +#ifdef CONFIG_CORE_TIMER_IRQ_L1 +__attribute__((l1_text)) +#endif +irqreturn_t timer_interrupt(int irq, void *dev_id); + +static struct clock_event_device clockevent_bfin = { + .name = "bfin_core_timer", + .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, + .shift = 32, + .cpumask = CPU_MASK_CPU0, + .set_next_event = bfin_timer_set_next_event, + .set_mode = bfin_timer_set_mode, +}; + +static struct irqaction bfin_timer_irq = { + .name = "Blackfin Core Timer", + .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL, + .handler = timer_interrupt, + .dev_id = &clockevent_bfin, +}; + +irqreturn_t timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *evt = dev_id; + evt->event_handler(evt); + return IRQ_HANDLED; +} + +static int __init bfin_clockevent_init(void) +{ + setup_irq(IRQ_CORETMR, &bfin_timer_irq); + bfin_timer_init(); + + clockevent_bfin.mult = div_sc(get_cclk(), NSEC_PER_SEC, clockevent_bfin.shift); + clockevent_bfin.max_delta_ns = clockevent_delta2ns(-1, &clockevent_bfin); + clockevent_bfin.min_delta_ns = clockevent_delta2ns(100, &clockevent_bfin); + clockevents_register_device(&clockevent_bfin); + + return 0; +} + +void __init time_init(void) +{ + time_t secs_since_1970 = (365 * 37 + 9) * 24 * 60 * 60; /* 1 Jan 2007 */ + +#ifdef CONFIG_RTC_DRV_BFIN + /* [#2663] hack to filter junk RTC values that would cause + * userspace to have to deal with time values greater than + * 2^31 seconds (which uClibc cannot cope with yet) + */ + if ((bfin_read_RTC_STAT() & 0xC0000000) == 0xC0000000) { + printk(KERN_NOTICE "bfin-rtc: invalid date; resetting\n"); + bfin_write_RTC_STAT(0); + } +#endif + + /* Initialize xtime. From now on, xtime is updated with timer interrupts */ + xtime.tv_sec = secs_since_1970; + xtime.tv_nsec = 0; + set_normalized_timespec(&wall_to_monotonic, -xtime.tv_sec, -xtime.tv_nsec); + + bfin_clocksource_init(); + bfin_clockevent_init(); +} |
