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Diffstat (limited to 'arch/arm/plat-orion/time.c')
| -rw-r--r-- | arch/arm/plat-orion/time.c | 244 |
1 files changed, 244 insertions, 0 deletions
diff --git a/arch/arm/plat-orion/time.c b/arch/arm/plat-orion/time.c new file mode 100644 index 00000000..69a61367 --- /dev/null +++ b/arch/arm/plat-orion/time.c @@ -0,0 +1,244 @@ +/* + * 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/sched.h> +#include <linux/timer.h> +#include <linux/clockchips.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <asm/sched_clock.h> + +/* + * MBus bridge block registers. + */ +#define BRIDGE_CAUSE_OFF 0x0110 +#define BRIDGE_MASK_OFF 0x0114 +#define BRIDGE_INT_TIMER0 0x0002 +#define BRIDGE_INT_TIMER1 0x0004 + + +/* + * Timer block registers. + */ +#define TIMER_CTRL_OFF 0x0000 +#define TIMER0_EN 0x0001 +#define TIMER0_RELOAD_EN 0x0002 +#define TIMER1_EN 0x0004 +#define TIMER1_RELOAD_EN 0x0008 +#define TIMER0_RELOAD_OFF 0x0010 +#define TIMER0_VAL_OFF 0x0014 +#define TIMER1_RELOAD_OFF 0x0018 +#define TIMER1_VAL_OFF 0x001c + + +/* + * SoC-specific data. + */ +static void __iomem *bridge_base; +static u32 bridge_timer1_clr_mask; +static void __iomem *timer_base; + + +/* + * Number of timer ticks per jiffy. + */ +static u32 ticks_per_jiffy; + + +/* + * Orion's sched_clock implementation. It has a resolution of + * at least 7.5ns (133MHz TCLK). + */ +static DEFINE_CLOCK_DATA(cd); + +unsigned long long notrace sched_clock(void) +{ + u32 cyc = ~readl(timer_base + TIMER0_VAL_OFF); + return cyc_to_sched_clock(&cd, cyc, (u32)~0); +} + + +static void notrace orion_update_sched_clock(void) +{ + u32 cyc = ~readl(timer_base + TIMER0_VAL_OFF); + update_sched_clock(&cd, cyc, (u32)~0); +} + +static void __init setup_sched_clock(unsigned long tclk) +{ + init_sched_clock(&cd, orion_update_sched_clock, 32, tclk); +} + +/* + * 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_timer1_clr_mask, bridge_base + BRIDGE_CAUSE_OFF); + + u = readl(bridge_base + BRIDGE_MASK_OFF); + u |= BRIDGE_INT_TIMER1; + writel(u, bridge_base + BRIDGE_MASK_OFF); + + /* + * Setup new clockevent timer value. + */ + writel(delta, timer_base + TIMER1_VAL_OFF); + + /* + * Enable the timer. + */ + u = readl(timer_base + TIMER_CTRL_OFF); + u = (u & ~TIMER1_RELOAD_EN) | TIMER1_EN; + writel(u, timer_base + TIMER_CTRL_OFF); + + 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, timer_base + TIMER1_RELOAD_OFF); + writel(ticks_per_jiffy - 1, timer_base + TIMER1_VAL_OFF); + + /* + * Enable timer interrupt. + */ + u = readl(bridge_base + BRIDGE_MASK_OFF); + writel(u | BRIDGE_INT_TIMER1, bridge_base + BRIDGE_MASK_OFF); + + /* + * Enable timer. + */ + u = readl(timer_base + TIMER_CTRL_OFF); + writel(u | TIMER1_EN | TIMER1_RELOAD_EN, + timer_base + TIMER_CTRL_OFF); + } else { + /* + * Disable timer. + */ + u = readl(timer_base + TIMER_CTRL_OFF); + writel(u & ~TIMER1_EN, timer_base + TIMER_CTRL_OFF); + + /* + * Disable timer interrupt. + */ + u = readl(bridge_base + BRIDGE_MASK_OFF); + writel(u & ~BRIDGE_INT_TIMER1, bridge_base + BRIDGE_MASK_OFF); + + /* + * ACK pending timer interrupt. + */ + writel(bridge_timer1_clr_mask, bridge_base + BRIDGE_CAUSE_OFF); + + } + 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, + .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_timer1_clr_mask, bridge_base + BRIDGE_CAUSE_OFF); + 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_set_base(u32 _timer_base) +{ + timer_base = (void __iomem *)_timer_base; +} + +void __init +orion_time_init(u32 _bridge_base, u32 _bridge_timer1_clr_mask, + unsigned int irq, unsigned int tclk) +{ + u32 u; + + /* + * Set SoC-specific data. + */ + bridge_base = (void __iomem *)_bridge_base; + bridge_timer1_clr_mask = _bridge_timer1_clr_mask; + + ticks_per_jiffy = (tclk + HZ/2) / HZ; + + /* + * Set scale and timer for sched_clock. + */ + setup_sched_clock(tclk); + + /* + * Setup free-running clocksource timer (interrupts + * disabled). + */ + writel(0xffffffff, timer_base + TIMER0_VAL_OFF); + writel(0xffffffff, timer_base + TIMER0_RELOAD_OFF); + u = readl(bridge_base + BRIDGE_MASK_OFF); + writel(u & ~BRIDGE_INT_TIMER0, bridge_base + BRIDGE_MASK_OFF); + u = readl(timer_base + TIMER_CTRL_OFF); + writel(u | TIMER0_EN | TIMER0_RELOAD_EN, timer_base + TIMER_CTRL_OFF); + clocksource_mmio_init(timer_base + TIMER0_VAL_OFF, "orion_clocksource", + tclk, 300, 32, clocksource_mmio_readl_down); + + /* + * 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); + orion_clkevt.cpumask = cpumask_of(0); + clockevents_register_device(&orion_clkevt); +} |