diff options
Diffstat (limited to 'drivers/clocksource/arm_arch_timer.c')
| -rw-r--r-- | drivers/clocksource/arm_arch_timer.c | 391 |
1 files changed, 391 insertions, 0 deletions
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c new file mode 100644 index 000000000000..d7ad425ab9b3 --- /dev/null +++ b/drivers/clocksource/arm_arch_timer.c @@ -0,0 +1,391 @@ +/* + * linux/drivers/clocksource/arm_arch_timer.c + * + * Copyright (C) 2011 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/device.h> +#include <linux/smp.h> +#include <linux/cpu.h> +#include <linux/clockchips.h> +#include <linux/interrupt.h> +#include <linux/of_irq.h> +#include <linux/io.h> + +#include <asm/arch_timer.h> +#include <asm/virt.h> + +#include <clocksource/arm_arch_timer.h> + +static u32 arch_timer_rate; + +enum ppi_nr { + PHYS_SECURE_PPI, + PHYS_NONSECURE_PPI, + VIRT_PPI, + HYP_PPI, + MAX_TIMER_PPI +}; + +static int arch_timer_ppi[MAX_TIMER_PPI]; + +static struct clock_event_device __percpu *arch_timer_evt; + +static bool arch_timer_use_virtual = true; + +/* + * Architected system timer support. + */ + +static inline irqreturn_t timer_handler(const int access, + struct clock_event_device *evt) +{ + unsigned long ctrl; + ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL); + if (ctrl & ARCH_TIMER_CTRL_IT_STAT) { + ctrl |= ARCH_TIMER_CTRL_IT_MASK; + arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl); + evt->event_handler(evt); + return IRQ_HANDLED; + } + + return IRQ_NONE; +} + +static irqreturn_t arch_timer_handler_virt(int irq, void *dev_id) +{ + struct clock_event_device *evt = dev_id; + + return timer_handler(ARCH_TIMER_VIRT_ACCESS, evt); +} + +static irqreturn_t arch_timer_handler_phys(int irq, void *dev_id) +{ + struct clock_event_device *evt = dev_id; + + return timer_handler(ARCH_TIMER_PHYS_ACCESS, evt); +} + +static inline void timer_set_mode(const int access, int mode) +{ + unsigned long ctrl; + switch (mode) { + case CLOCK_EVT_MODE_UNUSED: + case CLOCK_EVT_MODE_SHUTDOWN: + ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL); + ctrl &= ~ARCH_TIMER_CTRL_ENABLE; + arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl); + break; + default: + break; + } +} + +static void arch_timer_set_mode_virt(enum clock_event_mode mode, + struct clock_event_device *clk) +{ + timer_set_mode(ARCH_TIMER_VIRT_ACCESS, mode); +} + +static void arch_timer_set_mode_phys(enum clock_event_mode mode, + struct clock_event_device *clk) +{ + timer_set_mode(ARCH_TIMER_PHYS_ACCESS, mode); +} + +static inline void set_next_event(const int access, unsigned long evt) +{ + unsigned long ctrl; + ctrl = arch_timer_reg_read(access, ARCH_TIMER_REG_CTRL); + ctrl |= ARCH_TIMER_CTRL_ENABLE; + ctrl &= ~ARCH_TIMER_CTRL_IT_MASK; + arch_timer_reg_write(access, ARCH_TIMER_REG_TVAL, evt); + arch_timer_reg_write(access, ARCH_TIMER_REG_CTRL, ctrl); +} + +static int arch_timer_set_next_event_virt(unsigned long evt, + struct clock_event_device *unused) +{ + set_next_event(ARCH_TIMER_VIRT_ACCESS, evt); + return 0; +} + +static int arch_timer_set_next_event_phys(unsigned long evt, + struct clock_event_device *unused) +{ + set_next_event(ARCH_TIMER_PHYS_ACCESS, evt); + return 0; +} + +static int __cpuinit arch_timer_setup(struct clock_event_device *clk) +{ + clk->features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_C3STOP; + clk->name = "arch_sys_timer"; + clk->rating = 450; + if (arch_timer_use_virtual) { + clk->irq = arch_timer_ppi[VIRT_PPI]; + clk->set_mode = arch_timer_set_mode_virt; + clk->set_next_event = arch_timer_set_next_event_virt; + } else { + clk->irq = arch_timer_ppi[PHYS_SECURE_PPI]; + clk->set_mode = arch_timer_set_mode_phys; + clk->set_next_event = arch_timer_set_next_event_phys; + } + + clk->cpumask = cpumask_of(smp_processor_id()); + + clk->set_mode(CLOCK_EVT_MODE_SHUTDOWN, NULL); + + clockevents_config_and_register(clk, arch_timer_rate, + 0xf, 0x7fffffff); + + if (arch_timer_use_virtual) + enable_percpu_irq(arch_timer_ppi[VIRT_PPI], 0); + else { + enable_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI], 0); + if (arch_timer_ppi[PHYS_NONSECURE_PPI]) + enable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI], 0); + } + + arch_counter_set_user_access(); + + return 0; +} + +static int arch_timer_available(void) +{ + u32 freq; + + if (arch_timer_rate == 0) { + freq = arch_timer_get_cntfrq(); + + /* Check the timer frequency. */ + if (freq == 0) { + pr_warn("Architected timer frequency not available\n"); + return -EINVAL; + } + + arch_timer_rate = freq; + } + + pr_info_once("Architected local timer running at %lu.%02luMHz (%s).\n", + (unsigned long)arch_timer_rate / 1000000, + (unsigned long)(arch_timer_rate / 10000) % 100, + arch_timer_use_virtual ? "virt" : "phys"); + return 0; +} + +u32 arch_timer_get_rate(void) +{ + return arch_timer_rate; +} + +/* + * Some external users of arch_timer_read_counter (e.g. sched_clock) may try to + * call it before it has been initialised. Rather than incur a performance + * penalty checking for initialisation, provide a default implementation that + * won't lead to time appearing to jump backwards. + */ +static u64 arch_timer_read_zero(void) +{ + return 0; +} + +u64 (*arch_timer_read_counter)(void) = arch_timer_read_zero; + +static cycle_t arch_counter_read(struct clocksource *cs) +{ + return arch_timer_read_counter(); +} + +static cycle_t arch_counter_read_cc(const struct cyclecounter *cc) +{ + return arch_timer_read_counter(); +} + +static struct clocksource clocksource_counter = { + .name = "arch_sys_counter", + .rating = 400, + .read = arch_counter_read, + .mask = CLOCKSOURCE_MASK(56), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +static struct cyclecounter cyclecounter = { + .read = arch_counter_read_cc, + .mask = CLOCKSOURCE_MASK(56), +}; + +static struct timecounter timecounter; + +struct timecounter *arch_timer_get_timecounter(void) +{ + return &timecounter; +} + +static void __cpuinit arch_timer_stop(struct clock_event_device *clk) +{ + pr_debug("arch_timer_teardown disable IRQ%d cpu #%d\n", + clk->irq, smp_processor_id()); + + if (arch_timer_use_virtual) + disable_percpu_irq(arch_timer_ppi[VIRT_PPI]); + else { + disable_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI]); + if (arch_timer_ppi[PHYS_NONSECURE_PPI]) + disable_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI]); + } + + clk->set_mode(CLOCK_EVT_MODE_UNUSED, clk); +} + +static int __cpuinit arch_timer_cpu_notify(struct notifier_block *self, + unsigned long action, void *hcpu) +{ + struct clock_event_device *evt = this_cpu_ptr(arch_timer_evt); + + switch (action & ~CPU_TASKS_FROZEN) { + case CPU_STARTING: + arch_timer_setup(evt); + break; + case CPU_DYING: + arch_timer_stop(evt); + break; + } + + return NOTIFY_OK; +} + +static struct notifier_block arch_timer_cpu_nb __cpuinitdata = { + .notifier_call = arch_timer_cpu_notify, +}; + +static int __init arch_timer_register(void) +{ + int err; + int ppi; + + err = arch_timer_available(); + if (err) + goto out; + + arch_timer_evt = alloc_percpu(struct clock_event_device); + if (!arch_timer_evt) { + err = -ENOMEM; + goto out; + } + + clocksource_register_hz(&clocksource_counter, arch_timer_rate); + cyclecounter.mult = clocksource_counter.mult; + cyclecounter.shift = clocksource_counter.shift; + timecounter_init(&timecounter, &cyclecounter, + arch_counter_get_cntpct()); + + if (arch_timer_use_virtual) { + ppi = arch_timer_ppi[VIRT_PPI]; + err = request_percpu_irq(ppi, arch_timer_handler_virt, + "arch_timer", arch_timer_evt); + } else { + ppi = arch_timer_ppi[PHYS_SECURE_PPI]; + err = request_percpu_irq(ppi, arch_timer_handler_phys, + "arch_timer", arch_timer_evt); + if (!err && arch_timer_ppi[PHYS_NONSECURE_PPI]) { + ppi = arch_timer_ppi[PHYS_NONSECURE_PPI]; + err = request_percpu_irq(ppi, arch_timer_handler_phys, + "arch_timer", arch_timer_evt); + if (err) + free_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI], + arch_timer_evt); + } + } + + if (err) { + pr_err("arch_timer: can't register interrupt %d (%d)\n", + ppi, err); + goto out_free; + } + + err = register_cpu_notifier(&arch_timer_cpu_nb); + if (err) + goto out_free_irq; + + /* Immediately configure the timer on the boot CPU */ + arch_timer_setup(this_cpu_ptr(arch_timer_evt)); + + return 0; + +out_free_irq: + if (arch_timer_use_virtual) + free_percpu_irq(arch_timer_ppi[VIRT_PPI], arch_timer_evt); + else { + free_percpu_irq(arch_timer_ppi[PHYS_SECURE_PPI], + arch_timer_evt); + if (arch_timer_ppi[PHYS_NONSECURE_PPI]) + free_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI], + arch_timer_evt); + } + +out_free: + free_percpu(arch_timer_evt); +out: + return err; +} + +static const struct of_device_id arch_timer_of_match[] __initconst = { + { .compatible = "arm,armv7-timer", }, + { .compatible = "arm,armv8-timer", }, + {}, +}; + +int __init arch_timer_init(void) +{ + struct device_node *np; + u32 freq; + int i; + + np = of_find_matching_node(NULL, arch_timer_of_match); + if (!np) { + pr_err("arch_timer: can't find DT node\n"); + return -ENODEV; + } + + /* Try to determine the frequency from the device tree or CNTFRQ */ + if (!of_property_read_u32(np, "clock-frequency", &freq)) + arch_timer_rate = freq; + + for (i = PHYS_SECURE_PPI; i < MAX_TIMER_PPI; i++) + arch_timer_ppi[i] = irq_of_parse_and_map(np, i); + + of_node_put(np); + + /* + * If HYP mode is available, we know that the physical timer + * has been configured to be accessible from PL1. Use it, so + * that a guest can use the virtual timer instead. + * + * If no interrupt provided for virtual timer, we'll have to + * stick to the physical timer. It'd better be accessible... + */ + if (is_hyp_mode_available() || !arch_timer_ppi[VIRT_PPI]) { + arch_timer_use_virtual = false; + + if (!arch_timer_ppi[PHYS_SECURE_PPI] || + !arch_timer_ppi[PHYS_NONSECURE_PPI]) { + pr_warn("arch_timer: No interrupt available, giving up\n"); + return -EINVAL; + } + } + + if (arch_timer_use_virtual) + arch_timer_read_counter = arch_counter_get_cntvct; + else + arch_timer_read_counter = arch_counter_get_cntpct; + + return arch_timer_register(); +} |