diff options
Diffstat (limited to 'kernel/drivers/clocksource/timer-prima2.c')
| -rw-r--r-- | kernel/drivers/clocksource/timer-prima2.c | 233 |
1 files changed, 233 insertions, 0 deletions
diff --git a/kernel/drivers/clocksource/timer-prima2.c b/kernel/drivers/clocksource/timer-prima2.c new file mode 100644 index 000000000..ce18d570e --- /dev/null +++ b/kernel/drivers/clocksource/timer-prima2.c @@ -0,0 +1,233 @@ +/* + * 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/bitops.h> +#include <linux/irq.h> +#include <linux/clk.h> +#include <linux/err.h> +#include <linux/slab.h> +#include <linux/of.h> +#include <linux/of_irq.h> +#include <linux/of_address.h> +#include <linux/sched_clock.h> +#include <asm/mach/time.h> + +#define PRIMA2_CLOCK_FREQ 1000000 + +#define SIRFSOC_TIMER_COUNTER_LO 0x0000 +#define SIRFSOC_TIMER_COUNTER_HI 0x0004 +#define SIRFSOC_TIMER_MATCH_0 0x0008 +#define SIRFSOC_TIMER_MATCH_1 0x000C +#define SIRFSOC_TIMER_MATCH_2 0x0010 +#define SIRFSOC_TIMER_MATCH_3 0x0014 +#define SIRFSOC_TIMER_MATCH_4 0x0018 +#define SIRFSOC_TIMER_MATCH_5 0x001C +#define SIRFSOC_TIMER_STATUS 0x0020 +#define SIRFSOC_TIMER_INT_EN 0x0024 +#define SIRFSOC_TIMER_WATCHDOG_EN 0x0028 +#define SIRFSOC_TIMER_DIV 0x002C +#define SIRFSOC_TIMER_LATCH 0x0030 +#define SIRFSOC_TIMER_LATCHED_LO 0x0034 +#define SIRFSOC_TIMER_LATCHED_HI 0x0038 + +#define SIRFSOC_TIMER_WDT_INDEX 5 + +#define SIRFSOC_TIMER_LATCH_BIT BIT(0) + +#define SIRFSOC_TIMER_REG_CNT 11 + +static const u32 sirfsoc_timer_reg_list[SIRFSOC_TIMER_REG_CNT] = { + SIRFSOC_TIMER_MATCH_0, SIRFSOC_TIMER_MATCH_1, SIRFSOC_TIMER_MATCH_2, + SIRFSOC_TIMER_MATCH_3, SIRFSOC_TIMER_MATCH_4, SIRFSOC_TIMER_MATCH_5, + SIRFSOC_TIMER_INT_EN, SIRFSOC_TIMER_WATCHDOG_EN, SIRFSOC_TIMER_DIV, + SIRFSOC_TIMER_LATCHED_LO, SIRFSOC_TIMER_LATCHED_HI, +}; + +static u32 sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT]; + +static void __iomem *sirfsoc_timer_base; + +/* timer0 interrupt handler */ +static irqreturn_t sirfsoc_timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *ce = dev_id; + + WARN_ON(!(readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_STATUS) & + BIT(0))); + + /* clear timer0 interrupt */ + writel_relaxed(BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_STATUS); + + ce->event_handler(ce); + + return IRQ_HANDLED; +} + +/* read 64-bit timer counter */ +static cycle_t sirfsoc_timer_read(struct clocksource *cs) +{ + u64 cycles; + + /* latch the 64-bit timer counter */ + writel_relaxed(SIRFSOC_TIMER_LATCH_BIT, + sirfsoc_timer_base + SIRFSOC_TIMER_LATCH); + cycles = readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_LATCHED_HI); + cycles = (cycles << 32) | + readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_LATCHED_LO); + + return cycles; +} + +static int sirfsoc_timer_set_next_event(unsigned long delta, + struct clock_event_device *ce) +{ + unsigned long now, next; + + writel_relaxed(SIRFSOC_TIMER_LATCH_BIT, + sirfsoc_timer_base + SIRFSOC_TIMER_LATCH); + now = readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_LATCHED_LO); + next = now + delta; + writel_relaxed(next, sirfsoc_timer_base + SIRFSOC_TIMER_MATCH_0); + writel_relaxed(SIRFSOC_TIMER_LATCH_BIT, + sirfsoc_timer_base + SIRFSOC_TIMER_LATCH); + now = readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_LATCHED_LO); + + return next - now > delta ? -ETIME : 0; +} + +static void sirfsoc_timer_set_mode(enum clock_event_mode mode, + struct clock_event_device *ce) +{ + u32 val = readl_relaxed(sirfsoc_timer_base + SIRFSOC_TIMER_INT_EN); + switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: + WARN_ON(1); + break; + case CLOCK_EVT_MODE_ONESHOT: + writel_relaxed(val | BIT(0), + sirfsoc_timer_base + SIRFSOC_TIMER_INT_EN); + break; + case CLOCK_EVT_MODE_SHUTDOWN: + writel_relaxed(val & ~BIT(0), + sirfsoc_timer_base + SIRFSOC_TIMER_INT_EN); + break; + case CLOCK_EVT_MODE_UNUSED: + case CLOCK_EVT_MODE_RESUME: + break; + } +} + +static void sirfsoc_clocksource_suspend(struct clocksource *cs) +{ + int i; + + writel_relaxed(SIRFSOC_TIMER_LATCH_BIT, + sirfsoc_timer_base + SIRFSOC_TIMER_LATCH); + + 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_COUNTER_LO); + writel_relaxed(sirfsoc_timer_reg_val[SIRFSOC_TIMER_REG_CNT - 1], + sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_HI); +} + +static struct clock_event_device sirfsoc_clockevent = { + .name = "sirfsoc_clockevent", + .rating = 200, + .features = CLOCK_EVT_FEAT_ONESHOT, + .set_mode = sirfsoc_timer_set_mode, + .set_next_event = sirfsoc_timer_set_next_event, +}; + +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, + .irq = 0, + .handler = sirfsoc_timer_interrupt, + .dev_id = &sirfsoc_clockevent, +}; + +/* Overwrite weak default sched_clock with more precise one */ +static u64 notrace sirfsoc_read_sched_clock(void) +{ + return sirfsoc_timer_read(NULL); +} + +static void __init sirfsoc_clockevent_init(void) +{ + sirfsoc_clockevent.cpumask = cpumask_of(0); + clockevents_config_and_register(&sirfsoc_clockevent, PRIMA2_CLOCK_FREQ, + 2, -2); +} + +/* initialize the kernel jiffy timer source */ +static void __init sirfsoc_prima2_timer_init(struct device_node *np) +{ + unsigned long rate; + struct clk *clk; + + clk = of_clk_get(np, 0); + BUG_ON(IS_ERR(clk)); + + BUG_ON(clk_prepare_enable(clk)); + + rate = clk_get_rate(clk); + + BUG_ON(rate < PRIMA2_CLOCK_FREQ); + BUG_ON(rate % PRIMA2_CLOCK_FREQ); + + 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); + + writel_relaxed(rate / PRIMA2_CLOCK_FREQ / 2 - 1, + sirfsoc_timer_base + SIRFSOC_TIMER_DIV); + writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_LO); + writel_relaxed(0, sirfsoc_timer_base + SIRFSOC_TIMER_COUNTER_HI); + writel_relaxed(BIT(0), sirfsoc_timer_base + SIRFSOC_TIMER_STATUS); + + BUG_ON(clocksource_register_hz(&sirfsoc_clocksource, + PRIMA2_CLOCK_FREQ)); + + sched_clock_register(sirfsoc_read_sched_clock, 64, PRIMA2_CLOCK_FREQ); + + BUG_ON(setup_irq(sirfsoc_timer_irq.irq, &sirfsoc_timer_irq)); + + sirfsoc_clockevent_init(); +} +CLOCKSOURCE_OF_DECLARE(sirfsoc_prima2_timer, + "sirf,prima2-tick", sirfsoc_prima2_timer_init); |