--- /dev/null
+/*
+ * arch/metag/include/asm/clock.h
+ *
+ * Copyright (C) 2012 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.
+ */
+
+#ifndef _METAG_CLOCK_H_
+#define _METAG_CLOCK_H_
+
+#include <asm/mach/arch.h>
+
+/**
+ * struct meta_clock_desc - Meta Core clock callbacks.
+ * @get_core_freq: Get the frequency of the Meta core. If this is NULL, the
+ * core frequency will be determined like this:
+ * Meta 1: based on loops_per_jiffy.
+ * Meta 2: (EXPAND_TIMER_DIV + 1) MHz.
+ */
+struct meta_clock_desc {
+ unsigned long (*get_core_freq)(void);
+};
+
+extern struct meta_clock_desc _meta_clock;
+
+/*
+ * Set up the default clock, ensuring all callbacks are valid - only accessible
+ * during boot.
+ */
+void setup_meta_clocks(struct meta_clock_desc *desc);
+
+/**
+ * get_coreclock() - Get the frequency of the Meta core clock.
+ *
+ * Returns: The Meta core clock frequency in Hz.
+ */
+static inline unsigned long get_coreclock(void)
+{
+ /*
+ * Use the current clock callback. If set correctly this will provide
+ * the most accurate frequency as it can be calculated directly from the
+ * PLL configuration. otherwise a default callback will have been set
+ * instead.
+ */
+ return _meta_clock.get_core_freq();
+}
+
+#endif /* _METAG_CLOCK_H_ */
--- /dev/null
+/*
+ * arch/metag/kernel/clock.c
+ *
+ * Copyright (C) 2012 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.
+ */
+
+#include <linux/delay.h>
+#include <linux/io.h>
+
+#include <asm/param.h>
+#include <asm/clock.h>
+
+struct meta_clock_desc _meta_clock;
+
+/* Default machine get_core_freq callback. */
+static unsigned long get_core_freq_default(void)
+{
+#ifdef CONFIG_METAG_META21
+ /*
+ * Meta 2 cores divide down the core clock for the Meta timers, so we
+ * can estimate the core clock from the divider.
+ */
+ return (metag_in32(EXPAND_TIMER_DIV) + 1) * 1000000;
+#else
+ /*
+ * On Meta 1 we don't know the core clock, but assuming the Meta timer
+ * is correct it can be estimated based on loops_per_jiffy.
+ */
+ return (loops_per_jiffy * HZ * 5) >> 1;
+#endif
+}
+
+/**
+ * setup_meta_clocks() - Set up the Meta clock.
+ * @desc: Clock descriptor usually provided by machine description
+ *
+ * Ensures all callbacks are valid.
+ */
+void __init setup_meta_clocks(struct meta_clock_desc *desc)
+{
+ /* copy callbacks */
+ if (desc)
+ _meta_clock = *desc;
+
+ /* set fallback functions */
+ if (!_meta_clock.get_core_freq)
+ _meta_clock.get_core_freq = get_core_freq_default;
+}
+
--- /dev/null
+/*
+ * 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 <http://www.gnu.org/licenses/>.
+ *
+ *
+ * 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 <clocksource/metag_generic.h>
+#include <linux/cpu.h>
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/param.h>
+#include <linux/time.h>
+#include <linux/init.h>
+#include <linux/proc_fs.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <linux/interrupt.h>
+
+#include <asm/clock.h>
+#include <asm/hwthread.h>
+#include <asm/core_reg.h>
+#include <asm/metag_mem.h>
+#include <asm/tbx.h>
+
+#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;
+}
projects / kernel.git / commitdiff