From a2c5d4ed92bbc02ff4a37efc2adffe7d145abe4f Mon Sep 17 00:00:00 2001 From: James Hogan Date: Tue, 9 Oct 2012 10:54:39 +0100 Subject: metag: Time keeping Add time keeping code for metag. Meta hardware threads have 2 timers. The background timer (TXTIMER) is used as a free-running time base, and the interrupt timer (TXTIMERI) is used for the timer interrupt. Both counters traditionally count at approximately 1MHz. Signed-off-by: James Hogan Cc: John Stultz Cc: Thomas Gleixner --- drivers/clocksource/Kconfig | 5 + drivers/clocksource/Makefile | 1 + drivers/clocksource/metag_generic.c | 198 ++++++++++++++++++++++++++++++++++++ 3 files changed, 204 insertions(+) create mode 100644 drivers/clocksource/metag_generic.c (limited to 'drivers/clocksource') diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig index 7fdcbd3f4da..75bc7520ace 100644 --- a/drivers/clocksource/Kconfig +++ b/drivers/clocksource/Kconfig @@ -58,3 +58,8 @@ config CLKSRC_ARM_GENERIC def_bool y if ARM64 help This option enables support for the ARM generic timer. + +config CLKSRC_METAG_GENERIC + def_bool y if METAG + help + This option enables support for the Meta per-thread timers. diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile index f93453d0167..09dcd49b7e3 100644 --- a/drivers/clocksource/Makefile +++ b/drivers/clocksource/Makefile @@ -18,3 +18,4 @@ obj-$(CONFIG_ARCH_BCM2835) += bcm2835_timer.o obj-$(CONFIG_SUNXI_TIMER) += sunxi_timer.o obj-$(CONFIG_CLKSRC_ARM_GENERIC) += arm_generic.o +obj-$(CONFIG_CLKSRC_METAG_GENERIC) += metag_generic.o diff --git a/drivers/clocksource/metag_generic.c b/drivers/clocksource/metag_generic.c new file mode 100644 index 00000000000..ade7513a11d --- /dev/null +++ b/drivers/clocksource/metag_generic.c @@ -0,0 +1,198 @@ +/* + * Copyright (C) 2005-2013 Imagination Technologies Ltd. + * + * 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. + * + * 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, see . + * + * + * Support for Meta per-thread timers. + * + * Meta hardware threads have 2 timers. The background timer (TXTIMER) is used + * as a free-running time base (hz clocksource), and the interrupt timer + * (TXTIMERI) is used for the timer interrupt (clock event). Both counters + * traditionally count at approximately 1MHz. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include + +#define HARDWARE_FREQ 1000000 /* 1MHz */ +#define HARDWARE_DIV 1 /* divide by 1 = 1MHz clock */ +#define HARDWARE_TO_NS_SHIFT 10 /* convert ticks to ns */ + +static unsigned int hwtimer_freq = HARDWARE_FREQ; +static DEFINE_PER_CPU(struct clock_event_device, local_clockevent); +static DEFINE_PER_CPU(char [11], local_clockevent_name); + +static int metag_timer_set_next_event(unsigned long delta, + struct clock_event_device *dev) +{ + __core_reg_set(TXTIMERI, -delta); + return 0; +} + +static void metag_timer_set_mode(enum clock_event_mode mode, + struct clock_event_device *evt) +{ + switch (mode) { + case CLOCK_EVT_MODE_ONESHOT: + case CLOCK_EVT_MODE_RESUME: + break; + + case CLOCK_EVT_MODE_SHUTDOWN: + /* We should disable the IRQ here */ + break; + + case CLOCK_EVT_MODE_PERIODIC: + case CLOCK_EVT_MODE_UNUSED: + WARN_ON(1); + break; + }; +} + +static cycle_t metag_clocksource_read(struct clocksource *cs) +{ + return __core_reg_get(TXTIMER); +} + +static struct clocksource clocksource_metag = { + .name = "META", + .rating = 200, + .mask = CLOCKSOURCE_MASK(32), + .read = metag_clocksource_read, + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +static irqreturn_t metag_timer_interrupt(int irq, void *dummy) +{ + struct clock_event_device *evt = &__get_cpu_var(local_clockevent); + + evt->event_handler(evt); + + return IRQ_HANDLED; +} + +static struct irqaction metag_timer_irq = { + .name = "META core timer", + .handler = metag_timer_interrupt, + .flags = IRQF_TIMER | IRQF_IRQPOLL | IRQF_PERCPU, +}; + +unsigned long long sched_clock(void) +{ + unsigned long long ticks = __core_reg_get(TXTIMER); + return ticks << HARDWARE_TO_NS_SHIFT; +} + +static void __cpuinit arch_timer_setup(unsigned int cpu) +{ + unsigned int txdivtime; + struct clock_event_device *clk = &per_cpu(local_clockevent, cpu); + char *name = per_cpu(local_clockevent_name, cpu); + + txdivtime = __core_reg_get(TXDIVTIME); + + txdivtime &= ~TXDIVTIME_DIV_BITS; + txdivtime |= (HARDWARE_DIV & TXDIVTIME_DIV_BITS); + + __core_reg_set(TXDIVTIME, txdivtime); + + sprintf(name, "META %d", cpu); + clk->name = name; + clk->features = CLOCK_EVT_FEAT_ONESHOT, + + clk->rating = 200, + clk->shift = 12, + clk->irq = tbisig_map(TBID_SIGNUM_TRT), + clk->set_mode = metag_timer_set_mode, + clk->set_next_event = metag_timer_set_next_event, + + clk->mult = div_sc(hwtimer_freq, NSEC_PER_SEC, clk->shift); + clk->max_delta_ns = clockevent_delta2ns(0x7fffffff, clk); + clk->min_delta_ns = clockevent_delta2ns(0xf, clk); + clk->cpumask = cpumask_of(cpu); + + clockevents_register_device(clk); + + /* + * For all non-boot CPUs we need to synchronize our free + * running clock (TXTIMER) with the boot CPU's clock. + * + * While this won't be accurate, it should be close enough. + */ + if (cpu) { + unsigned int thread0 = cpu_2_hwthread_id[0]; + unsigned long val; + + val = core_reg_read(TXUCT_ID, TXTIMER_REGNUM, thread0); + __core_reg_set(TXTIMER, val); + } +} + +static int __cpuinit arch_timer_cpu_notify(struct notifier_block *self, + unsigned long action, void *hcpu) +{ + int cpu = (long)hcpu; + + switch (action) { + case CPU_STARTING: + case CPU_STARTING_FROZEN: + arch_timer_setup(cpu); + break; + } + + return NOTIFY_OK; +} + +static struct notifier_block __cpuinitdata arch_timer_cpu_nb = { + .notifier_call = arch_timer_cpu_notify, +}; + +int __init metag_generic_timer_init(void) +{ + /* + * On Meta 2 SoCs, the actual frequency of the timer is based on the + * Meta core clock speed divided by an integer, so it is only + * approximately 1MHz. Calculating the real frequency here drastically + * reduces clock skew on these SoCs. + */ +#ifdef CONFIG_METAG_META21 + hwtimer_freq = get_coreclock() / (metag_in32(EXPAND_TIMER_DIV) + 1); +#endif + clocksource_register_hz(&clocksource_metag, hwtimer_freq); + + setup_irq(tbisig_map(TBID_SIGNUM_TRT), &metag_timer_irq); + + /* Configure timer on boot CPU */ + arch_timer_setup(smp_processor_id()); + + /* Hook cpu boot to configure other CPU's timers */ + register_cpu_notifier(&arch_timer_cpu_nb); + + return 0; +} -- cgit v1.2.3