diff options
Diffstat (limited to 'drivers/clocksource/timer-atlas7.c')
| -rw-r--r-- | drivers/clocksource/timer-atlas7.c | 306 |
1 files changed, 306 insertions, 0 deletions
diff --git a/drivers/clocksource/timer-atlas7.c b/drivers/clocksource/timer-atlas7.c new file mode 100644 index 000000000000..60f9de3438b0 --- /dev/null +++ b/drivers/clocksource/timer-atlas7.c @@ -0,0 +1,306 @@ +/* + * System timer for CSR SiRFprimaII + * + * Copyright (c) 2011 Cambridge Silicon Radio Limited, a CSR plc group company. + * + * Licensed under GPLv2 or later. + */ + +#include <linux/kernel.h> +#include <linux/interrupt.h> +#include <linux/clockchips.h> +#include <linux/clocksource.h> +#include <linux/cpu.h> +#include <linux/bitops.h> +#include <linux/irq.h> +#include <linux/clk.h> +#include <linux/slab.h> +#include <linux/of.h> +#include <linux/of_irq.h> +#include <linux/of_address.h> +#include <linux/sched_clock.h> + +#define SIRFSOC_TIMER_32COUNTER_0_CTRL 0x0000 +#define SIRFSOC_TIMER_32COUNTER_1_CTRL 0x0004 +#define SIRFSOC_TIMER_MATCH_0 0x0018 +#define SIRFSOC_TIMER_MATCH_1 0x001c +#define SIRFSOC_TIMER_COUNTER_0 0x0048 +#define SIRFSOC_TIMER_COUNTER_1 0x004c +#define SIRFSOC_TIMER_INTR_STATUS 0x0060 +#define SIRFSOC_TIMER_WATCHDOG_EN 0x0064 +#define SIRFSOC_TIMER_64COUNTER_CTRL 0x0068 +#define SIRFSOC_TIMER_64COUNTER_LO 0x006c +#define SIRFSOC_TIMER_64COUNTER_HI 0x0070 +#define SIRFSOC_TIMER_64COUNTER_LOAD_LO 0x0074 +#define SIRFSOC_TIMER_64COUNTER_LOAD_HI 0x0078 +#define SIRFSOC_TIMER_64COUNTER_RLATCHED_LO 0x007c +#define SIRFSOC_TIMER_64COUNTER_RLATCHED_HI 0x0080 + +#define SIRFSOC_TIMER_REG_CNT 6 + +static unsigned long atlas7_timer_rate; + +static const u32 sirfsoc_timer_reg_list[SIRFSOC_TIMER_REG_CNT] = { + SIRFSOC_TIMER_WATCHDOG_EN, + SIRFSOC_TIMER_32COUNTER_0_CTRL, + SIRFSOC_TIMER_32COUNTER_1_CTRL, + SIRFSOC_TIMER_64COUNTER_CTRL, + SIRFSOC_TIMER_64COUNTER_RLATCHED_LO, + SIRFSOC_TIMER_64COUNTER_RLATCHED_HI, +}; + +static u32 sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT]; + +static void __iomem *sirfsoc_timer_base; + +/* disable count and interrupt */ +static inline void sirfsoc_timer_count_disable(int idx) +{ + writel_relaxed(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL + 4 * idx) & ~0x7, + sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL + 4 * idx); +} + +/* enable count and interrupt */ +static inline void sirfsoc_timer_count_enable(int idx) +{ + writel_relaxed(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL + 4 * idx) | 0x3, + sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL + 4 * idx); +} + +/* timer interrupt handler */ +static irqreturn_t sirfsoc_timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *ce = dev_id; + int cpu = smp_processor_id(); + + /* clear timer interrupt */ + writel_relaxed(BIT(cpu), sirfsoc_timer_base + SIRFSOC_TIMER_INTR_STATUS); + + if (ce->mode == CLOCK_EVT_MODE_ONESHOT) + sirfsoc_timer_count_disable(cpu); + + ce->event_handler(ce); + + return IRQ_HANDLED; +} + +/* read 64-bit timer counter */ +static cycle_t sirfsoc_timer_read(struct clocksource *cs) +{ + u64 cycles; + + writel_relaxed((readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL) | + BIT(0)) & ~BIT(1), sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL); + + cycles = readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_RLATCHED_HI); + cycles = (cycles << 32) | readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_RLATCHED_LO); + + return cycles; +} + +static int sirfsoc_timer_set_next_event(unsigned long delta, + struct clock_event_device *ce) +{ + int cpu = smp_processor_id(); + + /* disable timer first, then modify the related registers */ + sirfsoc_timer_count_disable(cpu); + + writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_0 + + 4 * cpu); + writel_relaxed(delta, sirfsoc_timer_base + SIRFSOC_TIMER_MATCH_0 + + 4 * cpu); + + /* enable the tick */ + sirfsoc_timer_count_enable(cpu); + + return 0; +} + +static void sirfsoc_timer_set_mode(enum clock_event_mode mode, + struct clock_event_device *ce) +{ + switch (mode) { + case CLOCK_EVT_MODE_ONESHOT: + /* enable in set_next_event */ + break; + default: + break; + } + + sirfsoc_timer_count_disable(smp_processor_id()); +} + +static void sirfsoc_clocksource_suspend(struct clocksource *cs) +{ + int i; + + for (i = 0; i < SIRFSOC_TIMER_REG_CNT; i++) + sirfsoc_timer_reg_val[i] = readl_relaxed(sirfsoc_timer_base + sirfsoc_timer_reg_list[i]); +} + +static void sirfsoc_clocksource_resume(struct clocksource *cs) +{ + int i; + + for (i = 0; i < SIRFSOC_TIMER_REG_CNT - 2; i++) + writel_relaxed(sirfsoc_timer_reg_val[i], sirfsoc_timer_base + sirfsoc_timer_reg_list[i]); + + writel_relaxed(sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT - 2], + sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_LO); + writel_relaxed(sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT - 1], + sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_HI); + + writel_relaxed(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL) | + BIT(1) | BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL); +} + +static struct clock_event_device __percpu *sirfsoc_clockevent; + +static struct clocksource sirfsoc_clocksource = { + .name = "sirfsoc_clocksource", + .rating = 200, + .mask = CLOCKSOURCE_MASK(64), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, + .read = sirfsoc_timer_read, + .suspend = sirfsoc_clocksource_suspend, + .resume = sirfsoc_clocksource_resume, +}; + +static struct irqaction sirfsoc_timer_irq = { + .name = "sirfsoc_timer0", + .flags = IRQF_TIMER | IRQF_NOBALANCING, + .handler = sirfsoc_timer_interrupt, +}; + +static struct irqaction sirfsoc_timer1_irq = { + .name = "sirfsoc_timer1", + .flags = IRQF_TIMER | IRQF_NOBALANCING, + .handler = sirfsoc_timer_interrupt, +}; + +static int sirfsoc_local_timer_setup(struct clock_event_device *ce) +{ + int cpu = smp_processor_id(); + struct irqaction *action; + + if (cpu == 0) + action = &sirfsoc_timer_irq; + else + action = &sirfsoc_timer1_irq; + + ce->irq = action->irq; + ce->name = "local_timer"; + ce->features = CLOCK_EVT_FEAT_ONESHOT; + ce->rating = 200; + ce->set_mode = sirfsoc_timer_set_mode; + ce->set_next_event = sirfsoc_timer_set_next_event; + clockevents_calc_mult_shift(ce, atlas7_timer_rate, 60); + ce->max_delta_ns = clockevent_delta2ns(-2, ce); + ce->min_delta_ns = clockevent_delta2ns(2, ce); + ce->cpumask = cpumask_of(cpu); + + action->dev_id = ce; + BUG_ON(setup_irq(ce->irq, action)); + irq_force_affinity(action->irq, cpumask_of(cpu)); + + clockevents_register_device(ce); + return 0; +} + +static void sirfsoc_local_timer_stop(struct clock_event_device *ce) +{ + int cpu = smp_processor_id(); + + sirfsoc_timer_count_disable(1); + + if (cpu == 0) + remove_irq(sirfsoc_timer_irq.irq, &sirfsoc_timer_irq); + else + remove_irq(sirfsoc_timer1_irq.irq, &sirfsoc_timer1_irq); +} + +static int sirfsoc_cpu_notify(struct notifier_block *self, + unsigned long action, void *hcpu) +{ + /* + * Grab cpu pointer in each case to avoid spurious + * preemptible warnings + */ + switch (action & ~CPU_TASKS_FROZEN) { + case CPU_STARTING: + sirfsoc_local_timer_setup(this_cpu_ptr(sirfsoc_clockevent)); + break; + case CPU_DYING: + sirfsoc_local_timer_stop(this_cpu_ptr(sirfsoc_clockevent)); + break; + } + + return NOTIFY_OK; +} + +static struct notifier_block sirfsoc_cpu_nb = { + .notifier_call = sirfsoc_cpu_notify, +}; + +static void __init sirfsoc_clockevent_init(void) +{ + sirfsoc_clockevent = alloc_percpu(struct clock_event_device); + BUG_ON(!sirfsoc_clockevent); + + BUG_ON(register_cpu_notifier(&sirfsoc_cpu_nb)); + + /* Immediately configure the timer on the boot CPU */ + sirfsoc_local_timer_setup(this_cpu_ptr(sirfsoc_clockevent)); +} + +/* initialize the kernel jiffy timer source */ +static void __init sirfsoc_atlas7_timer_init(struct device_node *np) +{ + struct clk *clk; + + clk = of_clk_get(np, 0); + BUG_ON(IS_ERR(clk)); + + BUG_ON(clk_prepare_enable(clk)); + + atlas7_timer_rate = clk_get_rate(clk); + + /* timer dividers: 0, not divided */ + writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL); + writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_0_CTRL); + writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_32COUNTER_1_CTRL); + + /* Initialize timer counters to 0 */ + writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_LO); + writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_LOAD_HI); + writel_relaxed(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL) | + BIT(1) | BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_64COUNTER_CTRL); + writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_0); + writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_1); + + /* Clear all interrupts */ + writel_relaxed(0xFFFF, sirfsoc_timer_base + SIRFSOC_TIMER_INTR_STATUS); + + BUG_ON(clocksource_register_hz(&sirfsoc_clocksource, atlas7_timer_rate)); + + sirfsoc_clockevent_init(); +} + +static void __init sirfsoc_of_timer_init(struct device_node *np) +{ + sirfsoc_timer_base = of_iomap(np, 0); + if (!sirfsoc_timer_base) + panic("unable to map timer cpu registers\n"); + + sirfsoc_timer_irq.irq = irq_of_parse_and_map(np, 0); + if (!sirfsoc_timer_irq.irq) + panic("No irq passed for timer0 via DT\n"); + + sirfsoc_timer1_irq.irq = irq_of_parse_and_map(np, 1); + if (!sirfsoc_timer1_irq.irq) + panic("No irq passed for timer1 via DT\n"); + + sirfsoc_atlas7_timer_init(np); +} +CLOCKSOURCE_OF_DECLARE(sirfsoc_atlas7_timer, "sirf,atlas7-tick", sirfsoc_of_timer_init); |