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/*
* Copyright (C) 2001-2006 Storlink, Corp.
* Copyright (C) 2008-2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <mach/hardware.h>
#include <mach/global_reg.h>
#include <asm/mach/time.h>
#include <linux/clockchips.h>
#include <linux/clocksource.h>
/*
* Register definitions for the timers
*/
#define TIMER1_BASE GEMINI_TIMER_BASE
#define TIMER2_BASE (GEMINI_TIMER_BASE + 0x10)
#define TIMER3_BASE (GEMINI_TIMER_BASE + 0x20)
#define TIMER_COUNT(BASE) (IO_ADDRESS(BASE) + 0x00)
#define TIMER_LOAD(BASE) (IO_ADDRESS(BASE) + 0x04)
#define TIMER_MATCH1(BASE) (IO_ADDRESS(BASE) + 0x08)
#define TIMER_MATCH2(BASE) (IO_ADDRESS(BASE) + 0x0C)
#define TIMER_CR (IO_ADDRESS(GEMINI_TIMER_BASE) + 0x30)
#define TIMER_INTR_STATE (IO_ADDRESS(GEMINI_TIMER_BASE) + 0x34)
#define TIMER_INTR_MASK (IO_ADDRESS(GEMINI_TIMER_BASE) + 0x38)
#define TIMER_1_CR_ENABLE (1 << 0)
#define TIMER_1_CR_CLOCK (1 << 1)
#define TIMER_1_CR_INT (1 << 2)
#define TIMER_2_CR_ENABLE (1 << 3)
#define TIMER_2_CR_CLOCK (1 << 4)
#define TIMER_2_CR_INT (1 << 5)
#define TIMER_3_CR_ENABLE (1 << 6)
#define TIMER_3_CR_CLOCK (1 << 7)
#define TIMER_3_CR_INT (1 << 8)
#define TIMER_1_CR_UPDOWN (1 << 9)
#define TIMER_2_CR_UPDOWN (1 << 10)
#define TIMER_3_CR_UPDOWN (1 << 11)
#define TIMER_DEFAULT_FLAGS (TIMER_1_CR_UPDOWN | \
TIMER_3_CR_ENABLE | \
TIMER_3_CR_UPDOWN)
#define TIMER_1_INT_MATCH1 (1 << 0)
#define TIMER_1_INT_MATCH2 (1 << 1)
#define TIMER_1_INT_OVERFLOW (1 << 2)
#define TIMER_2_INT_MATCH1 (1 << 3)
#define TIMER_2_INT_MATCH2 (1 << 4)
#define TIMER_2_INT_OVERFLOW (1 << 5)
#define TIMER_3_INT_MATCH1 (1 << 6)
#define TIMER_3_INT_MATCH2 (1 << 7)
#define TIMER_3_INT_OVERFLOW (1 << 8)
#define TIMER_INT_ALL_MASK 0x1ff
static unsigned int tick_rate;
static int gemini_timer_set_next_event(unsigned long cycles,
struct clock_event_device *evt)
{
u32 cr;
/* Setup the match register */
cr = readl(TIMER_COUNT(TIMER1_BASE));
writel(cr + cycles, TIMER_MATCH1(TIMER1_BASE));
if (readl(TIMER_COUNT(TIMER1_BASE)) - cr > cycles)
return -ETIME;
return 0;
}
static int gemini_timer_shutdown(struct clock_event_device *evt)
{
u32 cr;
/*
* Disable also for oneshot: the set_next() call will arm the timer
* instead.
*/
/* Stop timer and interrupt. */
cr = readl(TIMER_CR);
cr &= ~(TIMER_1_CR_ENABLE | TIMER_1_CR_INT);
writel(cr, TIMER_CR);
/* Setup counter start from 0 */
writel(0, TIMER_COUNT(TIMER1_BASE));
writel(0, TIMER_LOAD(TIMER1_BASE));
/* enable interrupt */
cr = readl(TIMER_INTR_MASK);
cr &= ~(TIMER_1_INT_OVERFLOW | TIMER_1_INT_MATCH2);
cr |= TIMER_1_INT_MATCH1;
writel(cr, TIMER_INTR_MASK);
/* start the timer */
cr = readl(TIMER_CR);
cr |= TIMER_1_CR_ENABLE;
writel(cr, TIMER_CR);
return 0;
}
static int gemini_timer_set_periodic(struct clock_event_device *evt)
{
u32 period = DIV_ROUND_CLOSEST(tick_rate, HZ);
u32 cr;
/* Stop timer and interrupt */
cr = readl(TIMER_CR);
cr &= ~(TIMER_1_CR_ENABLE | TIMER_1_CR_INT);
writel(cr, TIMER_CR);
/* Setup timer to fire at 1/HT intervals. */
cr = 0xffffffff - (period - 1);
writel(cr, TIMER_COUNT(TIMER1_BASE));
writel(cr, TIMER_LOAD(TIMER1_BASE));
/* enable interrupt on overflow */
cr = readl(TIMER_INTR_MASK);
cr &= ~(TIMER_1_INT_MATCH1 | TIMER_1_INT_MATCH2);
cr |= TIMER_1_INT_OVERFLOW;
writel(cr, TIMER_INTR_MASK);
/* Start the timer */
cr = readl(TIMER_CR);
cr |= TIMER_1_CR_ENABLE;
cr |= TIMER_1_CR_INT;
writel(cr, TIMER_CR);
return 0;
}
/* Use TIMER1 as clock event */
static struct clock_event_device gemini_clockevent = {
.name = "TIMER1",
/* Reasonably fast and accurate clock event */
.rating = 300,
.shift = 32,
.features = CLOCK_EVT_FEAT_PERIODIC |
CLOCK_EVT_FEAT_ONESHOT,
.set_next_event = gemini_timer_set_next_event,
.set_state_shutdown = gemini_timer_shutdown,
.set_state_periodic = gemini_timer_set_periodic,
.set_state_oneshot = gemini_timer_shutdown,
.tick_resume = gemini_timer_shutdown,
};
/*
* IRQ handler for the timer
*/
static irqreturn_t gemini_timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evt = &gemini_clockevent;
evt->event_handler(evt);
return IRQ_HANDLED;
}
static struct irqaction gemini_timer_irq = {
.name = "Gemini Timer Tick",
.flags = IRQF_TIMER,
.handler = gemini_timer_interrupt,
};
/*
* Set up timer interrupt, and return the current time in seconds.
*/
void __init gemini_timer_init(void)
{
u32 reg_v;
reg_v = readl(IO_ADDRESS(GEMINI_GLOBAL_BASE + GLOBAL_STATUS));
tick_rate = REG_TO_AHB_SPEED(reg_v) * 1000000;
printk(KERN_INFO "Bus: %dMHz", tick_rate / 1000000);
tick_rate /= 6; /* APB bus run AHB*(1/6) */
switch(reg_v & CPU_AHB_RATIO_MASK) {
case CPU_AHB_1_1:
printk(KERN_CONT "(1/1)\n");
break;
case CPU_AHB_3_2:
printk(KERN_CONT "(3/2)\n");
break;
case CPU_AHB_24_13:
printk(KERN_CONT "(24/13)\n");
break;
case CPU_AHB_2_1:
printk(KERN_CONT "(2/1)\n");
break;
}
/*
* Reset the interrupt mask and status
*/
writel(TIMER_INT_ALL_MASK, TIMER_INTR_MASK);
writel(0, TIMER_INTR_STATE);
writel(TIMER_DEFAULT_FLAGS, TIMER_CR);
/*
* Setup clockevent timer (interrupt-driven.)
*/
writel(0, TIMER_COUNT(TIMER1_BASE));
writel(0, TIMER_LOAD(TIMER1_BASE));
writel(0, TIMER_MATCH1(TIMER1_BASE));
writel(0, TIMER_MATCH2(TIMER1_BASE));
setup_irq(IRQ_TIMER1, &gemini_timer_irq);
gemini_clockevent.cpumask = cpumask_of(0);
clockevents_config_and_register(&gemini_clockevent, tick_rate,
1, 0xffffffff);
}
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