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Diffstat (limited to 'arch/arm/plat-orion/time.c')
| -rw-r--r-- | arch/arm/plat-orion/time.c | 203 |
1 files changed, 203 insertions, 0 deletions
diff --git a/arch/arm/plat-orion/time.c b/arch/arm/plat-orion/time.c new file mode 100644 index 000000000000..28b5285446e8 --- /dev/null +++ b/arch/arm/plat-orion/time.c @@ -0,0 +1,203 @@ +/* + * arch/arm/plat-orion/time.c + * + * Marvell Orion SoC timer handling. + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + * + * Timer 0 is used as free-running clocksource, while timer 1 is + * used as clock_event_device. + */ + +#include <linux/kernel.h> +#include <linux/clockchips.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <asm/mach/time.h> +#include <asm/arch/hardware.h> + +/* + * Number of timer ticks per jiffy. + */ +static u32 ticks_per_jiffy; + + +/* + * Timer block registers. + */ +#define TIMER_CTRL (TIMER_VIRT_BASE + 0x0000) +#define TIMER0_EN 0x0001 +#define TIMER0_RELOAD_EN 0x0002 +#define TIMER1_EN 0x0004 +#define TIMER1_RELOAD_EN 0x0008 +#define TIMER0_RELOAD (TIMER_VIRT_BASE + 0x0010) +#define TIMER0_VAL (TIMER_VIRT_BASE + 0x0014) +#define TIMER1_RELOAD (TIMER_VIRT_BASE + 0x0018) +#define TIMER1_VAL (TIMER_VIRT_BASE + 0x001c) + + +/* + * Clocksource handling. + */ +static cycle_t orion_clksrc_read(void) +{ + return 0xffffffff - readl(TIMER0_VAL); +} + +static struct clocksource orion_clksrc = { + .name = "orion_clocksource", + .shift = 20, + .rating = 300, + .read = orion_clksrc_read, + .mask = CLOCKSOURCE_MASK(32), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +}; + + + +/* + * Clockevent handling. + */ +static int +orion_clkevt_next_event(unsigned long delta, struct clock_event_device *dev) +{ + unsigned long flags; + u32 u; + + if (delta == 0) + return -ETIME; + + local_irq_save(flags); + + /* + * Clear and enable clockevent timer interrupt. + */ + writel(~BRIDGE_INT_TIMER1, BRIDGE_CAUSE); + + u = readl(BRIDGE_MASK); + u |= BRIDGE_INT_TIMER1; + writel(u, BRIDGE_MASK); + + /* + * Setup new clockevent timer value. + */ + writel(delta, TIMER1_VAL); + + /* + * Enable the timer. + */ + u = readl(TIMER_CTRL); + u = (u & ~TIMER1_RELOAD_EN) | TIMER1_EN; + writel(u, TIMER_CTRL); + + local_irq_restore(flags); + + return 0; +} + +static void +orion_clkevt_mode(enum clock_event_mode mode, struct clock_event_device *dev) +{ + unsigned long flags; + u32 u; + + local_irq_save(flags); + if (mode == CLOCK_EVT_MODE_PERIODIC) { + /* + * Setup timer to fire at 1/HZ intervals. + */ + writel(ticks_per_jiffy - 1, TIMER1_RELOAD); + writel(ticks_per_jiffy - 1, TIMER1_VAL); + + /* + * Enable timer interrupt. + */ + u = readl(BRIDGE_MASK); + writel(u | BRIDGE_INT_TIMER1, BRIDGE_MASK); + + /* + * Enable timer. + */ + u = readl(TIMER_CTRL); + writel(u | TIMER1_EN | TIMER1_RELOAD_EN, TIMER_CTRL); + } else { + /* + * Disable timer. + */ + u = readl(TIMER_CTRL); + writel(u & ~TIMER1_EN, TIMER_CTRL); + + /* + * Disable timer interrupt. + */ + u = readl(BRIDGE_MASK); + writel(u & ~BRIDGE_INT_TIMER1, BRIDGE_MASK); + + /* + * ACK pending timer interrupt. + */ + writel(~BRIDGE_INT_TIMER1, BRIDGE_CAUSE); + + } + local_irq_restore(flags); +} + +static struct clock_event_device orion_clkevt = { + .name = "orion_tick", + .features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC, + .shift = 32, + .rating = 300, + .cpumask = CPU_MASK_CPU0, + .set_next_event = orion_clkevt_next_event, + .set_mode = orion_clkevt_mode, +}; + +static irqreturn_t orion_timer_interrupt(int irq, void *dev_id) +{ + /* + * ACK timer interrupt and call event handler. + */ + writel(~BRIDGE_INT_TIMER1, BRIDGE_CAUSE); + orion_clkevt.event_handler(&orion_clkevt); + + return IRQ_HANDLED; +} + +static struct irqaction orion_timer_irq = { + .name = "orion_tick", + .flags = IRQF_DISABLED | IRQF_TIMER, + .handler = orion_timer_interrupt +}; + +void __init orion_time_init(unsigned int irq, unsigned int tclk) +{ + u32 u; + + ticks_per_jiffy = (tclk + HZ/2) / HZ; + + + /* + * Setup free-running clocksource timer (interrupts + * disabled.) + */ + writel(0xffffffff, TIMER0_VAL); + writel(0xffffffff, TIMER0_RELOAD); + u = readl(BRIDGE_MASK); + writel(u & ~BRIDGE_INT_TIMER0, BRIDGE_MASK); + u = readl(TIMER_CTRL); + writel(u | TIMER0_EN | TIMER0_RELOAD_EN, TIMER_CTRL); + orion_clksrc.mult = clocksource_hz2mult(tclk, orion_clksrc.shift); + clocksource_register(&orion_clksrc); + + + /* + * Setup clockevent timer (interrupt-driven.) + */ + setup_irq(irq, &orion_timer_irq); + orion_clkevt.mult = div_sc(tclk, NSEC_PER_SEC, orion_clkevt.shift); + orion_clkevt.max_delta_ns = clockevent_delta2ns(0xfffffffe, &orion_clkevt); + orion_clkevt.min_delta_ns = clockevent_delta2ns(1, &orion_clkevt); + clockevents_register_device(&orion_clkevt); +} |