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Diffstat (limited to 'arch/arm/plat-orion/time.c')
| -rw-r--r-- | arch/arm/plat-orion/time.c | 238 |
1 files changed, 238 insertions, 0 deletions
diff --git a/arch/arm/plat-orion/time.c b/arch/arm/plat-orion/time.c new file mode 100644 index 000000000..509d4824d --- /dev/null +++ b/arch/arm/plat-orion/time.c @@ -0,0 +1,238 @@ +/* + * 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/timer.h> +#include <linux/clockchips.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/sched_clock.h> +#include <plat/time.h> +#include <asm/delay.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 u64 notrace orion_read_sched_clock(void) +{ + return ~readl(timer_base + TIMER0_VAL_OFF); +} + +/* + * 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 int orion_clkevt_shutdown(struct clock_event_device *evt) +{ + unsigned long flags; + u32 u; + + local_irq_save(flags); + + /* 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); + + return 0; +} + +static int orion_clkevt_set_periodic(struct clock_event_device *evt) +{ + unsigned long flags; + u32 u; + + local_irq_save(flags); + + /* 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); + + local_irq_restore(flags); + + return 0; +} + +static struct clock_event_device orion_clkevt = { + .name = "orion_tick", + .features = CLOCK_EVT_FEAT_ONESHOT | + CLOCK_EVT_FEAT_PERIODIC, + .rating = 300, + .set_next_event = orion_clkevt_next_event, + .set_state_shutdown = orion_clkevt_shutdown, + .set_state_periodic = orion_clkevt_set_periodic, + .set_state_oneshot = orion_clkevt_shutdown, + .tick_resume = orion_clkevt_shutdown, +}; + +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; +} + +void __init +orion_time_set_base(void __iomem *_timer_base) +{ + timer_base = _timer_base; +} + +static unsigned long orion_delay_timer_read(void) +{ + return ~readl(timer_base + TIMER0_VAL_OFF); +} + +static struct delay_timer orion_delay_timer = { + .read_current_timer = orion_delay_timer_read, +}; + +void __init +orion_time_init(void __iomem *_bridge_base, u32 _bridge_timer1_clr_mask, + unsigned int irq, unsigned int tclk) +{ + u32 u; + + /* + * Set SoC-specific data. + */ + bridge_base = _bridge_base; + bridge_timer1_clr_mask = _bridge_timer1_clr_mask; + + ticks_per_jiffy = (tclk + HZ/2) / HZ; + + orion_delay_timer.freq = tclk; + register_current_timer_delay(&orion_delay_timer); + + /* + * Set scale and timer for sched_clock. + */ + sched_clock_register(orion_read_sched_clock, 32, 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). + */ + if (request_irq(irq, orion_timer_interrupt, IRQF_TIMER, "orion_tick", + NULL)) + pr_err("Failed to request irq %u (orion_tick)\n", irq); + orion_clkevt.cpumask = cpumask_of(0); + clockevents_config_and_register(&orion_clkevt, tclk, 1, 0xfffffffe); +} |