| /* |
| * linux/arch/arm/kernel/smp_twd.c |
| * |
| * Copyright (C) 2002 ARM Ltd. |
| * All Rights Reserved |
| * |
| * 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/init.h> |
| #include <linux/kernel.h> |
| #include <linux/clk.h> |
| #include <linux/cpu.h> |
| #include <linux/delay.h> |
| #include <linux/device.h> |
| #include <linux/err.h> |
| #include <linux/smp.h> |
| #include <linux/jiffies.h> |
| #include <linux/clockchips.h> |
| #include <linux/interrupt.h> |
| #include <linux/io.h> |
| #include <linux/of_irq.h> |
| #include <linux/of_address.h> |
| |
| #include <asm/smp_twd.h> |
| |
| /* set up by the platform code */ |
| static void __iomem *twd_base; |
| |
| static struct clk *twd_clk; |
| static unsigned long twd_timer_rate; |
| static DEFINE_PER_CPU(bool, percpu_setup_called); |
| |
| static struct clock_event_device __percpu *twd_evt; |
| static unsigned int twd_features = |
| CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT; |
| static int twd_ppi; |
| |
| static int twd_shutdown(struct clock_event_device *clk) |
| { |
| writel_relaxed(0, twd_base + TWD_TIMER_CONTROL); |
| return 0; |
| } |
| |
| static int twd_set_oneshot(struct clock_event_device *clk) |
| { |
| /* period set, and timer enabled in 'next_event' hook */ |
| writel_relaxed(TWD_TIMER_CONTROL_IT_ENABLE | TWD_TIMER_CONTROL_ONESHOT, |
| twd_base + TWD_TIMER_CONTROL); |
| return 0; |
| } |
| |
| static int twd_set_periodic(struct clock_event_device *clk) |
| { |
| unsigned long ctrl = TWD_TIMER_CONTROL_ENABLE | |
| TWD_TIMER_CONTROL_IT_ENABLE | |
| TWD_TIMER_CONTROL_PERIODIC; |
| |
| writel_relaxed(DIV_ROUND_CLOSEST(twd_timer_rate, HZ), |
| twd_base + TWD_TIMER_LOAD); |
| writel_relaxed(ctrl, twd_base + TWD_TIMER_CONTROL); |
| return 0; |
| } |
| |
| static int twd_set_next_event(unsigned long evt, |
| struct clock_event_device *unused) |
| { |
| unsigned long ctrl = readl_relaxed(twd_base + TWD_TIMER_CONTROL); |
| |
| ctrl |= TWD_TIMER_CONTROL_ENABLE; |
| |
| writel_relaxed(evt, twd_base + TWD_TIMER_COUNTER); |
| writel_relaxed(ctrl, twd_base + TWD_TIMER_CONTROL); |
| |
| return 0; |
| } |
| |
| /* |
| * local_timer_ack: checks for a local timer interrupt. |
| * |
| * If a local timer interrupt has occurred, acknowledge and return 1. |
| * Otherwise, return 0. |
| */ |
| static int twd_timer_ack(void) |
| { |
| if (readl_relaxed(twd_base + TWD_TIMER_INTSTAT)) { |
| writel_relaxed(1, twd_base + TWD_TIMER_INTSTAT); |
| return 1; |
| } |
| |
| return 0; |
| } |
| |
| static void twd_timer_stop(void) |
| { |
| struct clock_event_device *clk = raw_cpu_ptr(twd_evt); |
| |
| twd_shutdown(clk); |
| disable_percpu_irq(clk->irq); |
| } |
| |
| #ifdef CONFIG_COMMON_CLK |
| |
| /* |
| * Updates clockevent frequency when the cpu frequency changes. |
| * Called on the cpu that is changing frequency with interrupts disabled. |
| */ |
| static void twd_update_frequency(void *new_rate) |
| { |
| twd_timer_rate = *((unsigned long *) new_rate); |
| |
| clockevents_update_freq(raw_cpu_ptr(twd_evt), twd_timer_rate); |
| } |
| |
| static int twd_rate_change(struct notifier_block *nb, |
| unsigned long flags, void *data) |
| { |
| struct clk_notifier_data *cnd = data; |
| |
| /* |
| * The twd clock events must be reprogrammed to account for the new |
| * frequency. The timer is local to a cpu, so cross-call to the |
| * changing cpu. |
| */ |
| if (flags == POST_RATE_CHANGE) |
| on_each_cpu(twd_update_frequency, |
| (void *)&cnd->new_rate, 1); |
| |
| return NOTIFY_OK; |
| } |
| |
| static struct notifier_block twd_clk_nb = { |
| .notifier_call = twd_rate_change, |
| }; |
| |
| static int twd_clk_init(void) |
| { |
| if (twd_evt && raw_cpu_ptr(twd_evt) && !IS_ERR(twd_clk)) |
| return clk_notifier_register(twd_clk, &twd_clk_nb); |
| |
| return 0; |
| } |
| core_initcall(twd_clk_init); |
| |
| #elif defined (CONFIG_CPU_FREQ) |
| |
| #include <linux/cpufreq.h> |
| |
| /* |
| * Updates clockevent frequency when the cpu frequency changes. |
| * Called on the cpu that is changing frequency with interrupts disabled. |
| */ |
| static void twd_update_frequency(void *data) |
| { |
| twd_timer_rate = clk_get_rate(twd_clk); |
| |
| clockevents_update_freq(raw_cpu_ptr(twd_evt), twd_timer_rate); |
| } |
| |
| static int twd_cpufreq_transition(struct notifier_block *nb, |
| unsigned long state, void *data) |
| { |
| struct cpufreq_freqs *freqs = data; |
| |
| /* |
| * The twd clock events must be reprogrammed to account for the new |
| * frequency. The timer is local to a cpu, so cross-call to the |
| * changing cpu. |
| */ |
| if (state == CPUFREQ_POSTCHANGE) |
| smp_call_function_single(freqs->cpu, twd_update_frequency, |
| NULL, 1); |
| |
| return NOTIFY_OK; |
| } |
| |
| static struct notifier_block twd_cpufreq_nb = { |
| .notifier_call = twd_cpufreq_transition, |
| }; |
| |
| static int twd_cpufreq_init(void) |
| { |
| if (twd_evt && raw_cpu_ptr(twd_evt) && !IS_ERR(twd_clk)) |
| return cpufreq_register_notifier(&twd_cpufreq_nb, |
| CPUFREQ_TRANSITION_NOTIFIER); |
| |
| return 0; |
| } |
| core_initcall(twd_cpufreq_init); |
| |
| #endif |
| |
| static void twd_calibrate_rate(void) |
| { |
| unsigned long count; |
| u64 waitjiffies; |
| |
| /* |
| * If this is the first time round, we need to work out how fast |
| * the timer ticks |
| */ |
| if (twd_timer_rate == 0) { |
| pr_info("Calibrating local timer... "); |
| |
| /* Wait for a tick to start */ |
| waitjiffies = get_jiffies_64() + 1; |
| |
| while (get_jiffies_64() < waitjiffies) |
| udelay(10); |
| |
| /* OK, now the tick has started, let's get the timer going */ |
| waitjiffies += 5; |
| |
| /* enable, no interrupt or reload */ |
| writel_relaxed(0x1, twd_base + TWD_TIMER_CONTROL); |
| |
| /* maximum value */ |
| writel_relaxed(0xFFFFFFFFU, twd_base + TWD_TIMER_COUNTER); |
| |
| while (get_jiffies_64() < waitjiffies) |
| udelay(10); |
| |
| count = readl_relaxed(twd_base + TWD_TIMER_COUNTER); |
| |
| twd_timer_rate = (0xFFFFFFFFU - count) * (HZ / 5); |
| |
| pr_cont("%lu.%02luMHz.\n", twd_timer_rate / 1000000, |
| (twd_timer_rate / 10000) % 100); |
| } |
| } |
| |
| static irqreturn_t twd_handler(int irq, void *dev_id) |
| { |
| struct clock_event_device *evt = dev_id; |
| |
| if (twd_timer_ack()) { |
| evt->event_handler(evt); |
| return IRQ_HANDLED; |
| } |
| |
| return IRQ_NONE; |
| } |
| |
| static void twd_get_clock(struct device_node *np) |
| { |
| int err; |
| |
| if (np) |
| twd_clk = of_clk_get(np, 0); |
| else |
| twd_clk = clk_get_sys("smp_twd", NULL); |
| |
| if (IS_ERR(twd_clk)) { |
| pr_err("smp_twd: clock not found %d\n", (int) PTR_ERR(twd_clk)); |
| return; |
| } |
| |
| err = clk_prepare_enable(twd_clk); |
| if (err) { |
| pr_err("smp_twd: clock failed to prepare+enable: %d\n", err); |
| clk_put(twd_clk); |
| return; |
| } |
| |
| twd_timer_rate = clk_get_rate(twd_clk); |
| } |
| |
| /* |
| * Setup the local clock events for a CPU. |
| */ |
| static void twd_timer_setup(void) |
| { |
| struct clock_event_device *clk = raw_cpu_ptr(twd_evt); |
| int cpu = smp_processor_id(); |
| |
| /* |
| * If the basic setup for this CPU has been done before don't |
| * bother with the below. |
| */ |
| if (per_cpu(percpu_setup_called, cpu)) { |
| writel_relaxed(0, twd_base + TWD_TIMER_CONTROL); |
| clockevents_register_device(clk); |
| enable_percpu_irq(clk->irq, 0); |
| return; |
| } |
| per_cpu(percpu_setup_called, cpu) = true; |
| |
| twd_calibrate_rate(); |
| |
| /* |
| * The following is done once per CPU the first time .setup() is |
| * called. |
| */ |
| writel_relaxed(0, twd_base + TWD_TIMER_CONTROL); |
| |
| clk->name = "local_timer"; |
| clk->features = twd_features; |
| clk->rating = 350; |
| clk->set_state_shutdown = twd_shutdown; |
| clk->set_state_periodic = twd_set_periodic; |
| clk->set_state_oneshot = twd_set_oneshot; |
| clk->tick_resume = twd_shutdown; |
| clk->set_next_event = twd_set_next_event; |
| clk->irq = twd_ppi; |
| clk->cpumask = cpumask_of(cpu); |
| |
| clockevents_config_and_register(clk, twd_timer_rate, |
| 0xf, 0xffffffff); |
| enable_percpu_irq(clk->irq, 0); |
| } |
| |
| static int twd_timer_starting_cpu(unsigned int cpu) |
| { |
| twd_timer_setup(); |
| return 0; |
| } |
| |
| static int twd_timer_dying_cpu(unsigned int cpu) |
| { |
| twd_timer_stop(); |
| return 0; |
| } |
| |
| static int __init twd_local_timer_common_register(struct device_node *np) |
| { |
| int err; |
| |
| twd_evt = alloc_percpu(struct clock_event_device); |
| if (!twd_evt) { |
| err = -ENOMEM; |
| goto out_free; |
| } |
| |
| err = request_percpu_irq(twd_ppi, twd_handler, "twd", twd_evt); |
| if (err) { |
| pr_err("twd: can't register interrupt %d (%d)\n", twd_ppi, err); |
| goto out_free; |
| } |
| |
| cpuhp_setup_state_nocalls(CPUHP_AP_ARM_TWD_STARTING, |
| "AP_ARM_TWD_STARTING", |
| twd_timer_starting_cpu, twd_timer_dying_cpu); |
| |
| twd_get_clock(np); |
| if (!of_property_read_bool(np, "always-on")) |
| twd_features |= CLOCK_EVT_FEAT_C3STOP; |
| |
| /* |
| * Immediately configure the timer on the boot CPU, unless we need |
| * jiffies to be incrementing to calibrate the rate in which case |
| * setup the timer in late_time_init. |
| */ |
| if (twd_timer_rate) |
| twd_timer_setup(); |
| else |
| late_time_init = twd_timer_setup; |
| |
| return 0; |
| |
| out_free: |
| iounmap(twd_base); |
| twd_base = NULL; |
| free_percpu(twd_evt); |
| |
| return err; |
| } |
| |
| int __init twd_local_timer_register(struct twd_local_timer *tlt) |
| { |
| if (twd_base || twd_evt) |
| return -EBUSY; |
| |
| twd_ppi = tlt->res[1].start; |
| |
| twd_base = ioremap(tlt->res[0].start, resource_size(&tlt->res[0])); |
| if (!twd_base) |
| return -ENOMEM; |
| |
| return twd_local_timer_common_register(NULL); |
| } |
| |
| #ifdef CONFIG_OF |
| static int __init twd_local_timer_of_register(struct device_node *np) |
| { |
| int err; |
| |
| twd_ppi = irq_of_parse_and_map(np, 0); |
| if (!twd_ppi) { |
| err = -EINVAL; |
| goto out; |
| } |
| |
| twd_base = of_iomap(np, 0); |
| if (!twd_base) { |
| err = -ENOMEM; |
| goto out; |
| } |
| |
| err = twd_local_timer_common_register(np); |
| |
| out: |
| WARN(err, "twd_local_timer_of_register failed (%d)\n", err); |
| return err; |
| } |
| CLOCKSOURCE_OF_DECLARE(arm_twd_a9, "arm,cortex-a9-twd-timer", twd_local_timer_of_register); |
| CLOCKSOURCE_OF_DECLARE(arm_twd_a5, "arm,cortex-a5-twd-timer", twd_local_timer_of_register); |
| CLOCKSOURCE_OF_DECLARE(arm_twd_11mp, "arm,arm11mp-twd-timer", twd_local_timer_of_register); |
| #endif |