From 022c03a2d650c641fa0f94dbc9d9ff77f8057678 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Wed, 11 Jan 2012 17:25:17 +0000 Subject: ARM: local timers: Add A15 architected timer support Add support for the A15 generic timer and clocksource. As the timer generates interrupts on a different PPI depending on the execution mode (normal or secure), it is possible to register two different PPIs. Signed-off-by: Marc Zyngier --- arch/arm/kernel/Makefile | 1 + arch/arm/kernel/arch_timer.c | 288 +++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 289 insertions(+) create mode 100644 arch/arm/kernel/arch_timer.c (limited to 'arch/arm/kernel') diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile index 7b787d642af4..22b0f1e255f0 100644 --- a/arch/arm/kernel/Makefile +++ b/arch/arm/kernel/Makefile @@ -34,6 +34,7 @@ obj-$(CONFIG_ARM_CPU_SUSPEND) += sleep.o suspend.o obj-$(CONFIG_SMP) += smp.o smp_tlb.o obj-$(CONFIG_HAVE_ARM_SCU) += smp_scu.o obj-$(CONFIG_HAVE_ARM_TWD) += smp_twd.o +obj-$(CONFIG_ARM_ARCH_TIMER) += arch_timer.o obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o insn.o obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o insn.o obj-$(CONFIG_JUMP_LABEL) += jump_label.o insn.o patch.o diff --git a/arch/arm/kernel/arch_timer.c b/arch/arm/kernel/arch_timer.c new file mode 100644 index 000000000000..bb9a8b45bffa --- /dev/null +++ b/arch/arm/kernel/arch_timer.c @@ -0,0 +1,288 @@ +/* + * linux/arch/arm/kernel/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 +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include + +static unsigned long arch_timer_rate; +static int arch_timer_ppi; +static int arch_timer_ppi2; + +static struct clock_event_device __percpu **arch_timer_evt; + +/* + * Architected system timer support. + */ + +#define ARCH_TIMER_CTRL_ENABLE (1 << 0) +#define ARCH_TIMER_CTRL_IT_MASK (1 << 1) +#define ARCH_TIMER_CTRL_IT_STAT (1 << 2) + +#define ARCH_TIMER_REG_CTRL 0 +#define ARCH_TIMER_REG_FREQ 1 +#define ARCH_TIMER_REG_TVAL 2 + +static void arch_timer_reg_write(int reg, u32 val) +{ + switch (reg) { + case ARCH_TIMER_REG_CTRL: + asm volatile("mcr p15, 0, %0, c14, c2, 1" : : "r" (val)); + break; + case ARCH_TIMER_REG_TVAL: + asm volatile("mcr p15, 0, %0, c14, c2, 0" : : "r" (val)); + break; + } + + isb(); +} + +static u32 arch_timer_reg_read(int reg) +{ + u32 val; + + switch (reg) { + case ARCH_TIMER_REG_CTRL: + asm volatile("mrc p15, 0, %0, c14, c2, 1" : "=r" (val)); + break; + case ARCH_TIMER_REG_FREQ: + asm volatile("mrc p15, 0, %0, c14, c0, 0" : "=r" (val)); + break; + case ARCH_TIMER_REG_TVAL: + asm volatile("mrc p15, 0, %0, c14, c2, 0" : "=r" (val)); + break; + default: + BUG(); + } + + return val; +} + +static irqreturn_t arch_timer_handler(int irq, void *dev_id) +{ + struct clock_event_device *evt = *(struct clock_event_device **)dev_id; + unsigned long ctrl; + + ctrl = arch_timer_reg_read(ARCH_TIMER_REG_CTRL); + if (ctrl & ARCH_TIMER_CTRL_IT_STAT) { + ctrl |= ARCH_TIMER_CTRL_IT_MASK; + arch_timer_reg_write(ARCH_TIMER_REG_CTRL, ctrl); + evt->event_handler(evt); + return IRQ_HANDLED; + } + + return IRQ_NONE; +} + +static void arch_timer_disable(void) +{ + unsigned long ctrl; + + ctrl = arch_timer_reg_read(ARCH_TIMER_REG_CTRL); + ctrl &= ~ARCH_TIMER_CTRL_ENABLE; + arch_timer_reg_write(ARCH_TIMER_REG_CTRL, ctrl); +} + +static void arch_timer_set_mode(enum clock_event_mode mode, + struct clock_event_device *clk) +{ + switch (mode) { + case CLOCK_EVT_MODE_UNUSED: + case CLOCK_EVT_MODE_SHUTDOWN: + arch_timer_disable(); + break; + default: + break; + } +} + +static int arch_timer_set_next_event(unsigned long evt, + struct clock_event_device *unused) +{ + unsigned long ctrl; + + ctrl = arch_timer_reg_read(ARCH_TIMER_REG_CTRL); + ctrl |= ARCH_TIMER_CTRL_ENABLE; + ctrl &= ~ARCH_TIMER_CTRL_IT_MASK; + + arch_timer_reg_write(ARCH_TIMER_REG_TVAL, evt); + arch_timer_reg_write(ARCH_TIMER_REG_CTRL, ctrl); + + return 0; +} + +static int __cpuinit arch_timer_setup(struct clock_event_device *clk) +{ + /* Be safe... */ + arch_timer_disable(); + + clk->features = CLOCK_EVT_FEAT_ONESHOT; + clk->name = "arch_sys_timer"; + clk->rating = 450; + clk->set_mode = arch_timer_set_mode; + clk->set_next_event = arch_timer_set_next_event; + clk->irq = arch_timer_ppi; + + clockevents_config_and_register(clk, arch_timer_rate, + 0xf, 0x7fffffff); + + *__this_cpu_ptr(arch_timer_evt) = clk; + + enable_percpu_irq(clk->irq, 0); + if (arch_timer_ppi2) + enable_percpu_irq(arch_timer_ppi2, 0); + + return 0; +} + +/* Is the optional system timer available? */ +static int local_timer_is_architected(void) +{ + return (cpu_architecture() >= CPU_ARCH_ARMv7) && + ((read_cpuid_ext(CPUID_EXT_PFR1) >> 16) & 0xf) == 1; +} + +static int arch_timer_available(void) +{ + unsigned long freq; + + if (!local_timer_is_architected()) + return -ENXIO; + + if (arch_timer_rate == 0) { + arch_timer_reg_write(ARCH_TIMER_REG_CTRL, 0); + freq = arch_timer_reg_read(ARCH_TIMER_REG_FREQ); + + /* 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.\n", + arch_timer_rate / 1000000, (arch_timer_rate / 10000) % 100); + return 0; +} + +static inline cycle_t arch_counter_get_cntpct(void) +{ + u32 cvall, cvalh; + + asm volatile("mrrc p15, 0, %0, %1, c14" : "=r" (cvall), "=r" (cvalh)); + + return ((cycle_t) cvalh << 32) | cvall; +} + +static inline cycle_t arch_counter_get_cntvct(void) +{ + u32 cvall, cvalh; + + asm volatile("mrrc p15, 1, %0, %1, c14" : "=r" (cvall), "=r" (cvalh)); + + return ((cycle_t) cvalh << 32) | cvall; +} + +static cycle_t arch_counter_read(struct clocksource *cs) +{ + return arch_counter_get_cntpct(); +} + +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 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()); + disable_percpu_irq(clk->irq); + if (arch_timer_ppi2) + disable_percpu_irq(arch_timer_ppi2); + arch_timer_set_mode(CLOCK_EVT_MODE_UNUSED, clk); +} + +static struct local_timer_ops arch_timer_ops __cpuinitdata = { + .setup = arch_timer_setup, + .stop = arch_timer_stop, +}; + +int __init arch_timer_register(struct arch_timer *at) +{ + int err; + + if (at->res[0].start <= 0 || !(at->res[0].flags & IORESOURCE_IRQ)) + return -EINVAL; + + err = arch_timer_available(); + if (err) + return err; + + arch_timer_evt = alloc_percpu(struct clock_event_device *); + if (!arch_timer_evt) + return -ENOMEM; + + clocksource_register_hz(&clocksource_counter, arch_timer_rate); + + arch_timer_ppi = at->res[0].start; + err = request_percpu_irq(arch_timer_ppi, arch_timer_handler, + "arch_timer", arch_timer_evt); + if (err) { + pr_err("arch_timer: can't register interrupt %d (%d)\n", + arch_timer_ppi, err); + goto out_free; + } + + if (at->res[1].start > 0 || (at->res[1].flags & IORESOURCE_IRQ)) { + arch_timer_ppi2 = at->res[1].start; + err = request_percpu_irq(arch_timer_ppi2, arch_timer_handler, + "arch_timer", arch_timer_evt); + if (err) { + pr_err("arch_timer: can't register interrupt %d (%d)\n", + arch_timer_ppi2, err); + arch_timer_ppi2 = 0; + goto out_free_irq; + } + } + + err = local_timer_register(&arch_timer_ops); + if (err) + goto out_free_irq; + + return 0; + +out_free_irq: + free_percpu_irq(arch_timer_ppi, arch_timer_evt); + if (arch_timer_ppi2) + free_percpu_irq(arch_timer_ppi2, arch_timer_evt); + +out_free: + free_percpu(arch_timer_evt); + + return err; +} -- cgit v1.2.1