diff options
Diffstat (limited to 'drivers/clocksource/exynos_mct.c')
| -rw-r--r-- | drivers/clocksource/exynos_mct.c | 634 |
1 files changed, 634 insertions, 0 deletions
diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c new file mode 100644 index 000000000..c84461602 --- /dev/null +++ b/drivers/clocksource/exynos_mct.c @@ -0,0 +1,634 @@ +/* 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 <linux/sched.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/err.h> +#include <linux/clk.h> +#include <linux/clockchips.h> +#include <linux/cpu.h> +#include <linux/platform_device.h> +#include <linux/delay.h> +#include <linux/percpu.h> +#include <linux/of.h> +#include <linux/of_irq.h> +#include <linux/of_address.h> +#include <linux/clocksource.h> +#include <linux/sched_clock.h> + +#define EXYNOS4_MCTREG(x) (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_L_BASE EXYNOS4_MCTREG(0x300) +#define EXYNOS4_MCT_L_BASE(x) (_EXYNOS4_MCT_L_BASE + (0x100 * x)) +#define EXYNOS4_MCT_L_MASK (0xffffff00) + +#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) + +#define TICK_BASE_CNT 1 + +enum { + MCT_INT_SPI, + MCT_INT_PPI +}; + +enum { + MCT_G0_IRQ, + MCT_G1_IRQ, + MCT_G2_IRQ, + MCT_G3_IRQ, + MCT_L0_IRQ, + MCT_L1_IRQ, + MCT_L2_IRQ, + MCT_L3_IRQ, + MCT_L4_IRQ, + MCT_L5_IRQ, + MCT_L6_IRQ, + MCT_L7_IRQ, + MCT_NR_IRQS, +}; + +static void __iomem *reg_base; +static unsigned long clk_rate; +static unsigned int mct_int_type; +static int mct_irqs[MCT_NR_IRQS]; + +struct mct_clock_event_device { + struct clock_event_device evt; + unsigned long base; + char name[10]; +}; + +static void exynos4_mct_write(unsigned int value, unsigned long offset) +{ + unsigned long stat_addr; + u32 mask; + u32 i; + + writel_relaxed(value, reg_base + offset); + + if (likely(offset >= EXYNOS4_MCT_L_BASE(0))) { + stat_addr = (offset & EXYNOS4_MCT_L_MASK) + MCT_L_WSTAT_OFFSET; + switch (offset & ~EXYNOS4_MCT_L_MASK) { + case MCT_L_TCON_OFFSET: + mask = 1 << 3; /* L_TCON write status */ + break; + case MCT_L_ICNTB_OFFSET: + mask = 1 << 1; /* L_ICNTB write status */ + break; + case MCT_L_TCNTB_OFFSET: + mask = 1 << 0; /* L_TCNTB write status */ + break; + default: + return; + } + } else { + switch (offset) { + case EXYNOS4_MCT_G_TCON: + stat_addr = EXYNOS4_MCT_G_WSTAT; + mask = 1 << 16; /* G_TCON write status */ + break; + case EXYNOS4_MCT_G_COMP0_L: + stat_addr = EXYNOS4_MCT_G_WSTAT; + mask = 1 << 0; /* G_COMP0_L write status */ + break; + case EXYNOS4_MCT_G_COMP0_U: + stat_addr = EXYNOS4_MCT_G_WSTAT; + mask = 1 << 1; /* G_COMP0_U write status */ + break; + case EXYNOS4_MCT_G_COMP0_ADD_INCR: + stat_addr = EXYNOS4_MCT_G_WSTAT; + mask = 1 << 2; /* G_COMP0_ADD_INCR w status */ + break; + case EXYNOS4_MCT_G_CNT_L: + stat_addr = EXYNOS4_MCT_G_CNT_WSTAT; + mask = 1 << 0; /* G_CNT_L write status */ + break; + case EXYNOS4_MCT_G_CNT_U: + stat_addr = EXYNOS4_MCT_G_CNT_WSTAT; + mask = 1 << 1; /* G_CNT_U 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 (readl_relaxed(reg_base + stat_addr) & mask) { + writel_relaxed(mask, reg_base + stat_addr); + return; + } + + panic("MCT hangs after writing %d (offset:0x%lx)\n", value, offset); +} + +/* Clocksource handling */ +static void exynos4_mct_frc_start(void) +{ + u32 reg; + + reg = readl_relaxed(reg_base + EXYNOS4_MCT_G_TCON); + reg |= MCT_G_TCON_START; + exynos4_mct_write(reg, EXYNOS4_MCT_G_TCON); +} + +/** + * exynos4_read_count_64 - Read all 64-bits of the global counter + * + * This will read all 64-bits of the global counter taking care to make sure + * that the upper and lower half match. Note that reading the MCT can be quite + * slow (hundreds of nanoseconds) so you should use the 32-bit (lower half + * only) version when possible. + * + * Returns the number of cycles in the global counter. + */ +static u64 exynos4_read_count_64(void) +{ + unsigned int lo, hi; + u32 hi2 = readl_relaxed(reg_base + EXYNOS4_MCT_G_CNT_U); + + do { + hi = hi2; + lo = readl_relaxed(reg_base + EXYNOS4_MCT_G_CNT_L); + hi2 = readl_relaxed(reg_base + EXYNOS4_MCT_G_CNT_U); + } while (hi != hi2); + + return ((cycle_t)hi << 32) | lo; +} + +/** + * exynos4_read_count_32 - Read the lower 32-bits of the global counter + * + * This will read just the lower 32-bits of the global counter. This is marked + * as notrace so it can be used by the scheduler clock. + * + * Returns the number of cycles in the global counter (lower 32 bits). + */ +static u32 notrace exynos4_read_count_32(void) +{ + return readl_relaxed(reg_base + EXYNOS4_MCT_G_CNT_L); +} + +static cycle_t exynos4_frc_read(struct clocksource *cs) +{ + return exynos4_read_count_32(); +} + +static void exynos4_frc_resume(struct clocksource *cs) +{ + exynos4_mct_frc_start(); +} + +struct clocksource mct_frc = { + .name = "mct-frc", + .rating = 400, + .read = exynos4_frc_read, + .mask = CLOCKSOURCE_MASK(32), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, + .resume = exynos4_frc_resume, +}; + +static u64 notrace exynos4_read_sched_clock(void) +{ + return exynos4_read_count_32(); +} + +static struct delay_timer exynos4_delay_timer; + +static cycles_t exynos4_read_current_timer(void) +{ + BUILD_BUG_ON_MSG(sizeof(cycles_t) != sizeof(u32), + "cycles_t needs to move to 32-bit for ARM64 usage"); + return exynos4_read_count_32(); +} + +static void __init exynos4_clocksource_init(void) +{ + exynos4_mct_frc_start(); + + exynos4_delay_timer.read_current_timer = &exynos4_read_current_timer; + exynos4_delay_timer.freq = clk_rate; + register_current_timer_delay(&exynos4_delay_timer); + + if (clocksource_register_hz(&mct_frc, clk_rate)) + panic("%s: can't register clocksource\n", mct_frc.name); + + sched_clock_register(exynos4_read_sched_clock, 32, clk_rate); +} + +static void exynos4_mct_comp0_stop(void) +{ + unsigned int tcon; + + tcon = readl_relaxed(reg_base + 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 = readl_relaxed(reg_base + 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_read_count_64() + 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) +{ + unsigned long cycles_per_jiffy; + exynos4_mct_comp0_stop(); + + switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: + cycles_per_jiffy = + (((unsigned long long) NSEC_PER_SEC / HZ * evt->mult) >> evt->shift); + exynos4_mct_comp0_start(mode, cycles_per_jiffy); + 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) +{ + mct_comp_device.cpumask = cpumask_of(0); + clockevents_config_and_register(&mct_comp_device, clk_rate, + 0xf, 0xffffffff); + setup_irq(mct_irqs[MCT_G0_IRQ], &mct_comp_event_irq); +} + +static DEFINE_PER_CPU(struct mct_clock_event_device, percpu_mct_tick); + +/* 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; + unsigned long offset = mevt->base + MCT_L_TCON_OFFSET; + + tmp = readl_relaxed(reg_base + offset); + if (tmp & mask) { + tmp &= ~mask; + exynos4_mct_write(tmp, offset); + } +} + +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 interrupt */ + exynos4_mct_write(0x1, mevt->base + MCT_L_INT_ENB_OFFSET); + + tmp = readl_relaxed(reg_base + 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 = this_cpu_ptr(&percpu_mct_tick); + + 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 = this_cpu_ptr(&percpu_mct_tick); + unsigned long cycles_per_jiffy; + + exynos4_mct_tick_stop(mevt); + + switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: + cycles_per_jiffy = + (((unsigned long long) NSEC_PER_SEC / HZ * evt->mult) >> evt->shift); + exynos4_mct_tick_start(cycles_per_jiffy, mevt); + break; + + case CLOCK_EVT_MODE_ONESHOT: + case CLOCK_EVT_MODE_UNUSED: + case CLOCK_EVT_MODE_SHUTDOWN: + case CLOCK_EVT_MODE_RESUME: + break; + } +} + +static int exynos4_mct_tick_clear(struct mct_clock_event_device *mevt) +{ + 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 */ + if (readl_relaxed(reg_base + mevt->base + MCT_L_INT_CSTAT_OFFSET) & 1) { + exynos4_mct_write(0x1, mevt->base + MCT_L_INT_CSTAT_OFFSET); + return 1; + } else { + return 0; + } +} + +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; + + exynos4_mct_tick_clear(mevt); + + evt->event_handler(evt); + + return IRQ_HANDLED; +} + +static int exynos4_local_timer_setup(struct clock_event_device *evt) +{ + struct mct_clock_event_device *mevt; + unsigned int cpu = smp_processor_id(); + + mevt = container_of(evt, struct mct_clock_event_device, evt); + + mevt->base = EXYNOS4_MCT_L_BASE(cpu); + snprintf(mevt->name, sizeof(mevt->name), "mct_tick%d", cpu); + + evt->name = mevt->name; + 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; + + exynos4_mct_write(TICK_BASE_CNT, mevt->base + MCT_L_TCNTB_OFFSET); + + if (mct_int_type == MCT_INT_SPI) { + + if (evt->irq == -1) + return -EIO; + + irq_force_affinity(evt->irq, cpumask_of(cpu)); + enable_irq(evt->irq); + } else { + enable_percpu_irq(mct_irqs[MCT_L0_IRQ], 0); + } + clockevents_config_and_register(evt, clk_rate / (TICK_BASE_CNT + 1), + 0xf, 0x7fffffff); + + return 0; +} + +static void exynos4_local_timer_stop(struct clock_event_device *evt) +{ + evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt); + if (mct_int_type == MCT_INT_SPI) { + if (evt->irq != -1) + disable_irq_nosync(evt->irq); + } else { + disable_percpu_irq(mct_irqs[MCT_L0_IRQ]); + } +} + +static int exynos4_mct_cpu_notify(struct notifier_block *self, + unsigned long action, void *hcpu) +{ + struct mct_clock_event_device *mevt; + + /* + * Grab cpu pointer in each case to avoid spurious + * preemptible warnings + */ + switch (action & ~CPU_TASKS_FROZEN) { + case CPU_STARTING: + mevt = this_cpu_ptr(&percpu_mct_tick); + exynos4_local_timer_setup(&mevt->evt); + break; + case CPU_DYING: + mevt = this_cpu_ptr(&percpu_mct_tick); + exynos4_local_timer_stop(&mevt->evt); + break; + } + + return NOTIFY_OK; +} + +static struct notifier_block exynos4_mct_cpu_nb = { + .notifier_call = exynos4_mct_cpu_notify, +}; + +static void __init exynos4_timer_resources(struct device_node *np, void __iomem *base) +{ + int err, cpu; + struct mct_clock_event_device *mevt = this_cpu_ptr(&percpu_mct_tick); + struct clk *mct_clk, *tick_clk; + + tick_clk = np ? of_clk_get_by_name(np, "fin_pll") : + clk_get(NULL, "fin_pll"); + if (IS_ERR(tick_clk)) + panic("%s: unable to determine tick clock rate\n", __func__); + clk_rate = clk_get_rate(tick_clk); + + mct_clk = np ? of_clk_get_by_name(np, "mct") : clk_get(NULL, "mct"); + if (IS_ERR(mct_clk)) + panic("%s: unable to retrieve mct clock instance\n", __func__); + clk_prepare_enable(mct_clk); + + reg_base = base; + if (!reg_base) + panic("%s: unable to ioremap mct address space\n", __func__); + + if (mct_int_type == MCT_INT_PPI) { + + err = request_percpu_irq(mct_irqs[MCT_L0_IRQ], + exynos4_mct_tick_isr, "MCT", + &percpu_mct_tick); + WARN(err, "MCT: can't request IRQ %d (%d)\n", + mct_irqs[MCT_L0_IRQ], err); + } else { + for_each_possible_cpu(cpu) { + int mct_irq = mct_irqs[MCT_L0_IRQ + cpu]; + struct mct_clock_event_device *pcpu_mevt = + per_cpu_ptr(&percpu_mct_tick, cpu); + + pcpu_mevt->evt.irq = -1; + + irq_set_status_flags(mct_irq, IRQ_NOAUTOEN); + if (request_irq(mct_irq, + exynos4_mct_tick_isr, + IRQF_TIMER | IRQF_NOBALANCING, + pcpu_mevt->name, pcpu_mevt)) { + pr_err("exynos-mct: cannot register IRQ (cpu%d)\n", + cpu); + + continue; + } + pcpu_mevt->evt.irq = mct_irq; + } + } + + err = register_cpu_notifier(&exynos4_mct_cpu_nb); + if (err) + goto out_irq; + + /* Immediately configure the timer on the boot CPU */ + exynos4_local_timer_setup(&mevt->evt); + return; + +out_irq: + free_percpu_irq(mct_irqs[MCT_L0_IRQ], &percpu_mct_tick); +} + +void __init mct_init(void __iomem *base, int irq_g0, int irq_l0, int irq_l1) +{ + mct_irqs[MCT_G0_IRQ] = irq_g0; + mct_irqs[MCT_L0_IRQ] = irq_l0; + mct_irqs[MCT_L1_IRQ] = irq_l1; + mct_int_type = MCT_INT_SPI; + + exynos4_timer_resources(NULL, base); + exynos4_clocksource_init(); + exynos4_clockevent_init(); +} + +static void __init mct_init_dt(struct device_node *np, unsigned int int_type) +{ + u32 nr_irqs, i; + + mct_int_type = int_type; + + /* This driver uses only one global timer interrupt */ + mct_irqs[MCT_G0_IRQ] = irq_of_parse_and_map(np, MCT_G0_IRQ); + + /* + * Find out the number of local irqs specified. The local + * timer irqs are specified after the four global timer + * irqs are specified. + */ +#ifdef CONFIG_OF + nr_irqs = of_irq_count(np); +#else + nr_irqs = 0; +#endif + for (i = MCT_L0_IRQ; i < nr_irqs; i++) + mct_irqs[i] = irq_of_parse_and_map(np, i); + + exynos4_timer_resources(np, of_iomap(np, 0)); + exynos4_clocksource_init(); + exynos4_clockevent_init(); +} + + +static void __init mct_init_spi(struct device_node *np) +{ + return mct_init_dt(np, MCT_INT_SPI); +} + +static void __init mct_init_ppi(struct device_node *np) +{ + return mct_init_dt(np, MCT_INT_PPI); +} +CLOCKSOURCE_OF_DECLARE(exynos4210, "samsung,exynos4210-mct", mct_init_spi); +CLOCKSOURCE_OF_DECLARE(exynos4412, "samsung,exynos4412-mct", mct_init_ppi); |