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/*
* 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>
/*
* 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 u32 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 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,
.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(void __iomem *_timer_base)
{
timer_base = _timer_base;
}
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;
/*
* Set scale and timer for sched_clock.
*/
setup_sched_clock(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).
*/
setup_irq(irq, &orion_timer_irq);
orion_clkevt.cpumask = cpumask_of(0);
clockevents_config_and_register(&orion_clkevt, tclk, 1, 0xfffffffe);
}
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