diff options
Diffstat (limited to 'arch/arm/kernel/smp_twd.c')
| -rw-r--r-- | arch/arm/kernel/smp_twd.c | 326 |
1 files changed, 289 insertions, 37 deletions
diff --git a/arch/arm/kernel/smp_twd.c b/arch/arm/kernel/smp_twd.c index 35882fbf37f..dfc32130bc4 100644 --- a/arch/arm/kernel/smp_twd.c +++ b/arch/arm/kernel/smp_twd.c @@ -10,21 +10,31 @@ */ #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/irq.h> +#include <linux/interrupt.h> #include <linux/io.h> +#include <linux/of_irq.h> +#include <linux/of_address.h> +#include <asm/smp_plat.h> #include <asm/smp_twd.h> -#include <asm/hardware/gic.h> /* set up by the platform code */ -void __iomem *twd_base; +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 int twd_ppi; static void twd_set_mode(enum clock_event_mode mode, struct clock_event_device *clk) @@ -33,9 +43,10 @@ static void twd_set_mode(enum clock_event_mode mode, switch (mode) { case CLOCK_EVT_MODE_PERIODIC: - /* timer load already set up */ 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); break; case CLOCK_EVT_MODE_ONESHOT: /* period set, and timer enabled in 'next_event' hook */ @@ -47,18 +58,18 @@ static void twd_set_mode(enum clock_event_mode mode, ctrl = 0; } - __raw_writel(ctrl, twd_base + TWD_TIMER_CONTROL); + writel_relaxed(ctrl, twd_base + TWD_TIMER_CONTROL); } static int twd_set_next_event(unsigned long evt, struct clock_event_device *unused) { - unsigned long ctrl = __raw_readl(twd_base + TWD_TIMER_CONTROL); + unsigned long ctrl = readl_relaxed(twd_base + TWD_TIMER_CONTROL); ctrl |= TWD_TIMER_CONTROL_ENABLE; - __raw_writel(evt, twd_base + TWD_TIMER_COUNTER); - __raw_writel(ctrl, twd_base + TWD_TIMER_CONTROL); + writel_relaxed(evt, twd_base + TWD_TIMER_COUNTER); + writel_relaxed(ctrl, twd_base + TWD_TIMER_CONTROL); return 0; } @@ -69,19 +80,118 @@ static int twd_set_next_event(unsigned long evt, * If a local timer interrupt has occurred, acknowledge and return 1. * Otherwise, return 0. */ -int twd_timer_ack(void) +static int twd_timer_ack(void) { - if (__raw_readl(twd_base + TWD_TIMER_INTSTAT)) { - __raw_writel(1, twd_base + TWD_TIMER_INTSTAT); + if (readl_relaxed(twd_base + TWD_TIMER_INTSTAT)) { + writel_relaxed(1, twd_base + TWD_TIMER_INTSTAT); return 1; } return 0; } -static void __cpuinit twd_calibrate_rate(void) +static void twd_timer_stop(void) +{ + struct clock_event_device *clk = __this_cpu_ptr(twd_evt); + + twd_set_mode(CLOCK_EVT_MODE_UNUSED, 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(__this_cpu_ptr(twd_evt), twd_timer_rate); +} + +static int twd_rate_change(struct notifier_block *nb, + unsigned long flags, void *data) { - unsigned long load, count; + 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 && __this_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(__this_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 && __this_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; /* @@ -101,62 +211,204 @@ static void __cpuinit twd_calibrate_rate(void) waitjiffies += 5; /* enable, no interrupt or reload */ - __raw_writel(0x1, twd_base + TWD_TIMER_CONTROL); + writel_relaxed(0x1, twd_base + TWD_TIMER_CONTROL); /* maximum value */ - __raw_writel(0xFFFFFFFFU, twd_base + TWD_TIMER_COUNTER); + writel_relaxed(0xFFFFFFFFU, twd_base + TWD_TIMER_COUNTER); while (get_jiffies_64() < waitjiffies) udelay(10); - count = __raw_readl(twd_base + TWD_TIMER_COUNTER); + count = readl_relaxed(twd_base + TWD_TIMER_COUNTER); twd_timer_rate = (0xFFFFFFFFU - count) * (HZ / 5); printk("%lu.%02luMHz.\n", twd_timer_rate / 1000000, - (twd_timer_rate / 100000) % 100); + (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; } - load = twd_timer_rate / HZ; + 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; + } - __raw_writel(load, twd_base + TWD_TIMER_LOAD); + twd_timer_rate = clk_get_rate(twd_clk); } /* * Setup the local clock events for a CPU. */ -void __cpuinit twd_timer_setup(struct clock_event_device *clk) +static void twd_timer_setup(void) { - unsigned long flags; + struct clock_event_device *clk = __this_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 = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_C3STOP; clk->rating = 350; clk->set_mode = twd_set_mode; clk->set_next_event = twd_set_next_event; - clk->shift = 20; - clk->mult = div_sc(twd_timer_rate, NSEC_PER_SEC, clk->shift); - clk->max_delta_ns = clockevent_delta2ns(0xffffffff, clk); - clk->min_delta_ns = clockevent_delta2ns(0xf, clk); + 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); +} - /* Make sure our local interrupt controller has this enabled */ - local_irq_save(flags); - irq_to_desc(clk->irq)->status |= IRQ_NOPROBE; - get_irq_chip(clk->irq)->unmask(clk->irq); - local_irq_restore(flags); +static int twd_timer_cpu_notify(struct notifier_block *self, + unsigned long action, void *hcpu) +{ + switch (action & ~CPU_TASKS_FROZEN) { + case CPU_STARTING: + twd_timer_setup(); + break; + case CPU_DYING: + twd_timer_stop(); + break; + } - clockevents_register_device(clk); + return NOTIFY_OK; } -#ifdef CONFIG_HOTPLUG_CPU -/* - * take a local timer down - */ -void twd_timer_stop(void) +static struct notifier_block twd_timer_cpu_nb = { + .notifier_call = twd_timer_cpu_notify, +}; + +static int __init twd_local_timer_common_register(struct device_node *np) { - __raw_writel(0, twd_base + TWD_TIMER_CONTROL); + 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; + } + + err = register_cpu_notifier(&twd_timer_cpu_nb); + if (err) + goto out_irq; + + twd_get_clock(np); + + /* + * 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_irq: + free_percpu_irq(twd_ppi, twd_evt); +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 void __init twd_local_timer_of_register(struct device_node *np) +{ + int err; + + if (!is_smp() || !setup_max_cpus) + return; + + 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); } +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 |