From: Changhwan Youn Date: Fri, 11 Mar 2011 01:39:57 +0000 (+0900) Subject: ARM: EXYNOS4: Implement kernel timers using MCT X-Git-Tag: v2.6.39-rc1~434^2^2~24^2 X-Git-Url: http://pileus.org/git/?a=commitdiff_plain;h=30d8bead5a309492d1dae2f6511a0465fe6ad05e;p=~andy%2Flinux ARM: EXYNOS4: Implement kernel timers using MCT The Multi-Core Timer(MCT) of EXYNOS4 is designed for implementing clock source timer and clock event timers. This patch implements 1 clock source timer with 64 bit free running counter of MCT and 2 clock event timers with two of 31-bit tick counters. Signed-off-by: Changhwan Youn Cc: Ben Dooks Cc: Russell King Signed-off-by: Kukjin Kim --- diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index ec3bf985613..b4db99bb4f8 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1366,7 +1366,7 @@ config LOCAL_TIMERS bool "Use local timer interrupts" depends on SMP default y - select HAVE_ARM_TWD if !ARCH_MSM_SCORPIONMP + select HAVE_ARM_TWD if (!ARCH_MSM_SCORPIONMP && !EXYNOS4_MCT) help Enable support for local timers on SMP platforms, rather then the legacy IPI broadcast method. Local timers allows the system diff --git a/arch/arm/mach-exynos4/Kconfig b/arch/arm/mach-exynos4/Kconfig index ad55ce78b37..82195a9a4c6 100644 --- a/arch/arm/mach-exynos4/Kconfig +++ b/arch/arm/mach-exynos4/Kconfig @@ -15,6 +15,11 @@ config CPU_EXYNOS4210 help Enable EXYNOS4210 CPU support +config EXYNOS4_MCT + bool "Kernel timer support by MCT" + help + Use MCT (Multi Core Timer) as kernel timers + config EXYNOS4_DEV_PD bool help diff --git a/arch/arm/mach-exynos4/Makefile b/arch/arm/mach-exynos4/Makefile index 45422cb3e5b..56e367b48fb 100644 --- a/arch/arm/mach-exynos4/Makefile +++ b/arch/arm/mach-exynos4/Makefile @@ -13,11 +13,18 @@ obj- := # Core support for EXYNOS4 system obj-$(CONFIG_CPU_EXYNOS4210) += cpu.o init.o clock.o irq-combiner.o -obj-$(CONFIG_CPU_EXYNOS4210) += setup-i2c0.o time.o gpiolib.o irq-eint.o dma.o +obj-$(CONFIG_CPU_EXYNOS4210) += setup-i2c0.o gpiolib.o irq-eint.o dma.o obj-$(CONFIG_CPU_FREQ) += cpufreq.o obj-$(CONFIG_SMP) += platsmp.o headsmp.o + +ifeq ($(CONFIG_EXYNOS4_MCT),y) +obj-y += mct.o +else +obj-y += time.o obj-$(CONFIG_LOCAL_TIMERS) += localtimer.o +endif + obj-$(CONFIG_HOTPLUG_CPU) += hotplug.o # machine support diff --git a/arch/arm/mach-exynos4/include/mach/regs-mct.h b/arch/arm/mach-exynos4/include/mach/regs-mct.h new file mode 100644 index 00000000000..ca9c8434b02 --- /dev/null +++ b/arch/arm/mach-exynos4/include/mach/regs-mct.h @@ -0,0 +1,52 @@ +/* arch/arm/mach-exynos4/include/mach/regs-mct.h + * + * Copyright (c) 2011 Samsung Electronics Co., Ltd. + * http://www.samsung.com + * + * EXYNOS4 MCT configutation + * + * 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 __ASM_ARCH_REGS_MCT_H +#define __ASM_ARCH_REGS_MCT_H __FILE__ + +#include + +#define EXYNOS4_MCTREG(x) (S5P_VA_SYSTIMER + (x)) + +#define EXYNOS4_MCT_G_CNT_L EXYNOS4_MCTREG(0x100) +#define EXYNOS4_MCT_G_CNT_U EXYNOS4_MCTREG(0x104) +#define EXYNOS4_MCT_G_CNT_WSTAT EXYNOS4_MCTREG(0x110) + +#define EXYNOS4_MCT_G_COMP0_L EXYNOS4_MCTREG(0x200) +#define EXYNOS4_MCT_G_COMP0_U EXYNOS4_MCTREG(0x204) +#define EXYNOS4_MCT_G_COMP0_ADD_INCR EXYNOS4_MCTREG(0x208) + +#define EXYNOS4_MCT_G_TCON EXYNOS4_MCTREG(0x240) + +#define EXYNOS4_MCT_G_INT_CSTAT EXYNOS4_MCTREG(0x244) +#define EXYNOS4_MCT_G_INT_ENB EXYNOS4_MCTREG(0x248) +#define EXYNOS4_MCT_G_WSTAT EXYNOS4_MCTREG(0x24C) + +#define EXYNOS4_MCT_L0_BASE EXYNOS4_MCTREG(0x300) +#define EXYNOS4_MCT_L1_BASE EXYNOS4_MCTREG(0x400) + +#define MCT_L_TCNTB_OFFSET (0x00) +#define MCT_L_ICNTB_OFFSET (0x08) +#define MCT_L_TCON_OFFSET (0x20) +#define MCT_L_INT_CSTAT_OFFSET (0x30) +#define MCT_L_INT_ENB_OFFSET (0x34) +#define MCT_L_WSTAT_OFFSET (0x40) + +#define MCT_G_TCON_START (1 << 8) +#define MCT_G_TCON_COMP0_AUTO_INC (1 << 1) +#define MCT_G_TCON_COMP0_ENABLE (1 << 0) + +#define MCT_L_TCON_INTERVAL_MODE (1 << 2) +#define MCT_L_TCON_INT_START (1 << 1) +#define MCT_L_TCON_TIMER_START (1 << 0) + +#endif /* __ASM_ARCH_REGS_MCT_H */ diff --git a/arch/arm/mach-exynos4/mct.c b/arch/arm/mach-exynos4/mct.c new file mode 100644 index 00000000000..af82a8fbb68 --- /dev/null +++ b/arch/arm/mach-exynos4/mct.c @@ -0,0 +1,421 @@ +/* linux/arch/arm/mach-exynos4/mct.c + * + * Copyright (c) 2011 Samsung Electronics Co., Ltd. + * http://www.samsung.com + * + * EXYNOS4 MCT(Multi-Core Timer) support + * + * 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 + +static unsigned long clk_cnt_per_tick; +static unsigned long clk_rate; + +struct mct_clock_event_device { + struct clock_event_device *evt; + void __iomem *base; +}; + +struct mct_clock_event_device mct_tick[2]; + +static void exynos4_mct_write(unsigned int value, void *addr) +{ + void __iomem *stat_addr; + u32 mask; + u32 i; + + __raw_writel(value, addr); + + switch ((u32) addr) { + case (u32) EXYNOS4_MCT_G_TCON: + stat_addr = EXYNOS4_MCT_G_WSTAT; + mask = 1 << 16; /* G_TCON write status */ + break; + case (u32) EXYNOS4_MCT_G_COMP0_L: + stat_addr = EXYNOS4_MCT_G_WSTAT; + mask = 1 << 0; /* G_COMP0_L write status */ + break; + case (u32) EXYNOS4_MCT_G_COMP0_U: + stat_addr = EXYNOS4_MCT_G_WSTAT; + mask = 1 << 1; /* G_COMP0_U write status */ + break; + case (u32) EXYNOS4_MCT_G_COMP0_ADD_INCR: + stat_addr = EXYNOS4_MCT_G_WSTAT; + mask = 1 << 2; /* G_COMP0_ADD_INCR write status */ + break; + case (u32) EXYNOS4_MCT_G_CNT_L: + stat_addr = EXYNOS4_MCT_G_CNT_WSTAT; + mask = 1 << 0; /* G_CNT_L write status */ + break; + case (u32) EXYNOS4_MCT_G_CNT_U: + stat_addr = EXYNOS4_MCT_G_CNT_WSTAT; + mask = 1 << 1; /* G_CNT_U write status */ + break; + case (u32)(EXYNOS4_MCT_L0_BASE + MCT_L_TCON_OFFSET): + stat_addr = EXYNOS4_MCT_L0_BASE + MCT_L_WSTAT_OFFSET; + mask = 1 << 3; /* L0_TCON write status */ + break; + case (u32)(EXYNOS4_MCT_L1_BASE + MCT_L_TCON_OFFSET): + stat_addr = EXYNOS4_MCT_L1_BASE + MCT_L_WSTAT_OFFSET; + mask = 1 << 3; /* L1_TCON write status */ + break; + case (u32)(EXYNOS4_MCT_L0_BASE + MCT_L_TCNTB_OFFSET): + stat_addr = EXYNOS4_MCT_L0_BASE + MCT_L_WSTAT_OFFSET; + mask = 1 << 0; /* L0_TCNTB write status */ + break; + case (u32)(EXYNOS4_MCT_L1_BASE + MCT_L_TCNTB_OFFSET): + stat_addr = EXYNOS4_MCT_L1_BASE + MCT_L_WSTAT_OFFSET; + mask = 1 << 0; /* L1_TCNTB write status */ + break; + case (u32)(EXYNOS4_MCT_L0_BASE + MCT_L_ICNTB_OFFSET): + stat_addr = EXYNOS4_MCT_L0_BASE + MCT_L_WSTAT_OFFSET; + mask = 1 << 1; /* L0_ICNTB write status */ + break; + case (u32)(EXYNOS4_MCT_L1_BASE + MCT_L_ICNTB_OFFSET): + stat_addr = EXYNOS4_MCT_L1_BASE + MCT_L_WSTAT_OFFSET; + mask = 1 << 1; /* L1_ICNTB write status */ + break; + default: + return; + } + + /* Wait maximum 1 ms until written values are applied */ + for (i = 0; i < loops_per_jiffy / 1000 * HZ; i++) + if (__raw_readl(stat_addr) & mask) { + __raw_writel(mask, stat_addr); + return; + } + + panic("MCT hangs after writing %d (addr:0x%08x)\n", value, (u32)addr); +} + +/* Clocksource handling */ +static void exynos4_mct_frc_start(u32 hi, u32 lo) +{ + u32 reg; + + exynos4_mct_write(lo, EXYNOS4_MCT_G_CNT_L); + exynos4_mct_write(hi, EXYNOS4_MCT_G_CNT_U); + + reg = __raw_readl(EXYNOS4_MCT_G_TCON); + reg |= MCT_G_TCON_START; + exynos4_mct_write(reg, EXYNOS4_MCT_G_TCON); +} + +static cycle_t exynos4_frc_read(struct clocksource *cs) +{ + unsigned int lo, hi; + u32 hi2 = __raw_readl(EXYNOS4_MCT_G_CNT_U); + + do { + hi = hi2; + lo = __raw_readl(EXYNOS4_MCT_G_CNT_L); + hi2 = __raw_readl(EXYNOS4_MCT_G_CNT_U); + } while (hi != hi2); + + return ((cycle_t)hi << 32) | lo; +} + +struct clocksource mct_frc = { + .name = "mct-frc", + .rating = 400, + .read = exynos4_frc_read, + .mask = CLOCKSOURCE_MASK(64), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + +static void __init exynos4_clocksource_init(void) +{ + exynos4_mct_frc_start(0, 0); + + if (clocksource_register_hz(&mct_frc, clk_rate)) + panic("%s: can't register clocksource\n", mct_frc.name); +} + +static void exynos4_mct_comp0_stop(void) +{ + unsigned int tcon; + + tcon = __raw_readl(EXYNOS4_MCT_G_TCON); + tcon &= ~(MCT_G_TCON_COMP0_ENABLE | MCT_G_TCON_COMP0_AUTO_INC); + + exynos4_mct_write(tcon, EXYNOS4_MCT_G_TCON); + exynos4_mct_write(0, EXYNOS4_MCT_G_INT_ENB); +} + +static void exynos4_mct_comp0_start(enum clock_event_mode mode, + unsigned long cycles) +{ + unsigned int tcon; + cycle_t comp_cycle; + + tcon = __raw_readl(EXYNOS4_MCT_G_TCON); + + if (mode == CLOCK_EVT_MODE_PERIODIC) { + tcon |= MCT_G_TCON_COMP0_AUTO_INC; + exynos4_mct_write(cycles, EXYNOS4_MCT_G_COMP0_ADD_INCR); + } + + comp_cycle = exynos4_frc_read(&mct_frc) + cycles; + exynos4_mct_write((u32)comp_cycle, EXYNOS4_MCT_G_COMP0_L); + exynos4_mct_write((u32)(comp_cycle >> 32), EXYNOS4_MCT_G_COMP0_U); + + exynos4_mct_write(0x1, EXYNOS4_MCT_G_INT_ENB); + + tcon |= MCT_G_TCON_COMP0_ENABLE; + exynos4_mct_write(tcon , EXYNOS4_MCT_G_TCON); +} + +static int exynos4_comp_set_next_event(unsigned long cycles, + struct clock_event_device *evt) +{ + exynos4_mct_comp0_start(evt->mode, cycles); + + return 0; +} + +static void exynos4_comp_set_mode(enum clock_event_mode mode, + struct clock_event_device *evt) +{ + exynos4_mct_comp0_stop(); + + switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: + exynos4_mct_comp0_start(mode, clk_cnt_per_tick); + break; + + case CLOCK_EVT_MODE_ONESHOT: + case CLOCK_EVT_MODE_UNUSED: + case CLOCK_EVT_MODE_SHUTDOWN: + case CLOCK_EVT_MODE_RESUME: + break; + } +} + +static struct clock_event_device mct_comp_device = { + .name = "mct-comp", + .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, + .rating = 250, + .set_next_event = exynos4_comp_set_next_event, + .set_mode = exynos4_comp_set_mode, +}; + +static irqreturn_t exynos4_mct_comp_isr(int irq, void *dev_id) +{ + struct clock_event_device *evt = dev_id; + + exynos4_mct_write(0x1, EXYNOS4_MCT_G_INT_CSTAT); + + evt->event_handler(evt); + + return IRQ_HANDLED; +} + +static struct irqaction mct_comp_event_irq = { + .name = "mct_comp_irq", + .flags = IRQF_TIMER | IRQF_IRQPOLL, + .handler = exynos4_mct_comp_isr, + .dev_id = &mct_comp_device, +}; + +static void exynos4_clockevent_init(void) +{ + clk_cnt_per_tick = clk_rate / 2 / HZ; + + clockevents_calc_mult_shift(&mct_comp_device, clk_rate / 2, 5); + mct_comp_device.max_delta_ns = + clockevent_delta2ns(0xffffffff, &mct_comp_device); + mct_comp_device.min_delta_ns = + clockevent_delta2ns(0xf, &mct_comp_device); + mct_comp_device.cpumask = cpumask_of(0); + clockevents_register_device(&mct_comp_device); + + setup_irq(IRQ_MCT_G0, &mct_comp_event_irq); +} + +#ifdef CONFIG_LOCAL_TIMERS +/* Clock event handling */ +static void exynos4_mct_tick_stop(struct mct_clock_event_device *mevt) +{ + unsigned long tmp; + unsigned long mask = MCT_L_TCON_INT_START | MCT_L_TCON_TIMER_START; + void __iomem *addr = mevt->base + MCT_L_TCON_OFFSET; + + tmp = __raw_readl(addr); + if (tmp & mask) { + tmp &= ~mask; + exynos4_mct_write(tmp, addr); + } +} + +static void exynos4_mct_tick_start(unsigned long cycles, + struct mct_clock_event_device *mevt) +{ + unsigned long tmp; + + exynos4_mct_tick_stop(mevt); + + tmp = (1 << 31) | cycles; /* MCT_L_UPDATE_ICNTB */ + + /* update interrupt count buffer */ + exynos4_mct_write(tmp, mevt->base + MCT_L_ICNTB_OFFSET); + + /* enable MCT tick interupt */ + exynos4_mct_write(0x1, mevt->base + MCT_L_INT_ENB_OFFSET); + + tmp = __raw_readl(mevt->base + MCT_L_TCON_OFFSET); + tmp |= MCT_L_TCON_INT_START | MCT_L_TCON_TIMER_START | + MCT_L_TCON_INTERVAL_MODE; + exynos4_mct_write(tmp, mevt->base + MCT_L_TCON_OFFSET); +} + +static int exynos4_tick_set_next_event(unsigned long cycles, + struct clock_event_device *evt) +{ + struct mct_clock_event_device *mevt = &mct_tick[smp_processor_id()]; + + exynos4_mct_tick_start(cycles, mevt); + + return 0; +} + +static inline void exynos4_tick_set_mode(enum clock_event_mode mode, + struct clock_event_device *evt) +{ + struct mct_clock_event_device *mevt = &mct_tick[smp_processor_id()]; + + exynos4_mct_tick_stop(mevt); + + switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: + exynos4_mct_tick_start(clk_cnt_per_tick, mevt); + break; + + case CLOCK_EVT_MODE_ONESHOT: + case CLOCK_EVT_MODE_UNUSED: + case CLOCK_EVT_MODE_SHUTDOWN: + case CLOCK_EVT_MODE_RESUME: + break; + } +} + +static irqreturn_t exynos4_mct_tick_isr(int irq, void *dev_id) +{ + struct mct_clock_event_device *mevt = dev_id; + struct clock_event_device *evt = mevt->evt; + + /* + * This is for supporting oneshot mode. + * Mct would generate interrupt periodically + * without explicit stopping. + */ + if (evt->mode != CLOCK_EVT_MODE_PERIODIC) + exynos4_mct_tick_stop(mevt); + + /* Clear the MCT tick interrupt */ + exynos4_mct_write(0x1, mevt->base + MCT_L_INT_CSTAT_OFFSET); + + evt->event_handler(evt); + + return IRQ_HANDLED; +} + +static struct irqaction mct_tick0_event_irq = { + .name = "mct_tick0_irq", + .flags = IRQF_TIMER | IRQF_NOBALANCING, + .handler = exynos4_mct_tick_isr, +}; + +static struct irqaction mct_tick1_event_irq = { + .name = "mct_tick1_irq", + .flags = IRQF_TIMER | IRQF_NOBALANCING, + .handler = exynos4_mct_tick_isr, +}; + +static void exynos4_mct_tick_init(struct clock_event_device *evt) +{ + unsigned int cpu = smp_processor_id(); + + mct_tick[cpu].evt = evt; + + if (cpu == 0) { + mct_tick[cpu].base = EXYNOS4_MCT_L0_BASE; + evt->name = "mct_tick0"; + } else { + mct_tick[cpu].base = EXYNOS4_MCT_L1_BASE; + evt->name = "mct_tick1"; + } + + evt->cpumask = cpumask_of(cpu); + evt->set_next_event = exynos4_tick_set_next_event; + evt->set_mode = exynos4_tick_set_mode; + evt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT; + evt->rating = 450; + + clockevents_calc_mult_shift(evt, clk_rate / 2, 5); + evt->max_delta_ns = + clockevent_delta2ns(0x7fffffff, evt); + evt->min_delta_ns = + clockevent_delta2ns(0xf, evt); + + clockevents_register_device(evt); + + exynos4_mct_write(0x1, mct_tick[cpu].base + MCT_L_TCNTB_OFFSET); + + if (cpu == 0) { + mct_tick0_event_irq.dev_id = &mct_tick[cpu]; + setup_irq(IRQ_MCT_L0, &mct_tick0_event_irq); + } else { + mct_tick1_event_irq.dev_id = &mct_tick[cpu]; + irq_set_affinity(IRQ_MCT1, cpumask_of(1)); + setup_irq(IRQ_MCT_L1, &mct_tick1_event_irq); + } +} + +/* Setup the local clock events for a CPU */ +void __cpuinit local_timer_setup(struct clock_event_device *evt) +{ + exynos4_mct_tick_init(evt); +} + +int local_timer_ack(void) +{ + return 0; +} + +#endif /* CONFIG_LOCAL_TIMERS */ + +static void __init exynos4_timer_resources(void) +{ + struct clk *mct_clk; + mct_clk = clk_get(NULL, "xtal"); + + clk_rate = clk_get_rate(mct_clk); +} + +static void __init exynos4_timer_init(void) +{ + exynos4_timer_resources(); + exynos4_clocksource_init(); + exynos4_clockevent_init(); +} + +struct sys_timer exynos4_timer = { + .init = exynos4_timer_init, +};