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/*
* linux/arch/arm/mach-omap2/timer-gp.c
*
* OMAP2 GP timer support.
*
* Copyright (C) 2005 Nokia Corporation
* Author: Paul Mundt <paul.mundt@nokia.com>
* Juha Yrjölä <juha.yrjola@nokia.com>
*
* Some parts based off of TI's 24xx code:
*
* Copyright (C) 2004 Texas Instruments, Inc.
*
* Roughly modelled after the OMAP1 MPU timer code.
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/init.h>
#include <linux/time.h>
#include <linux/interrupt.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <asm/mach/time.h>
#include <asm/delay.h>
#include <asm/io.h>
#define OMAP2_GP_TIMER1_BASE 0x48028000
#define OMAP2_GP_TIMER2_BASE 0x4802a000
#define OMAP2_GP_TIMER3_BASE 0x48078000
#define OMAP2_GP_TIMER4_BASE 0x4807a000
#define GP_TIMER_TIDR 0x00
#define GP_TIMER_TISR 0x18
#define GP_TIMER_TIER 0x1c
#define GP_TIMER_TCLR 0x24
#define GP_TIMER_TCRR 0x28
#define GP_TIMER_TLDR 0x2c
#define GP_TIMER_TSICR 0x40
#define OS_TIMER_NR 1 /* GP timer 2 */
static unsigned long timer_base[] = {
IO_ADDRESS(OMAP2_GP_TIMER1_BASE),
IO_ADDRESS(OMAP2_GP_TIMER2_BASE),
IO_ADDRESS(OMAP2_GP_TIMER3_BASE),
IO_ADDRESS(OMAP2_GP_TIMER4_BASE),
};
static inline unsigned int timer_read_reg(int nr, unsigned int reg)
{
return __raw_readl(timer_base[nr] + reg);
}
static inline void timer_write_reg(int nr, unsigned int reg, unsigned int val)
{
__raw_writel(val, timer_base[nr] + reg);
}
/* Note that we always enable the clock prescale divider bit */
static inline void omap2_gp_timer_start(int nr, unsigned long load_val)
{
unsigned int tmp;
tmp = 0xffffffff - load_val;
timer_write_reg(nr, GP_TIMER_TLDR, tmp);
timer_write_reg(nr, GP_TIMER_TCRR, tmp);
timer_write_reg(nr, GP_TIMER_TIER, 1 << 1);
timer_write_reg(nr, GP_TIMER_TCLR, (1 << 5) | (1 << 1) | 1);
}
static irqreturn_t omap2_gp_timer_interrupt(int irq, void *dev_id,
struct pt_regs *regs)
{
write_seqlock(&xtime_lock);
timer_write_reg(OS_TIMER_NR, GP_TIMER_TISR, 1 << 1);
timer_tick(regs);
write_sequnlock(&xtime_lock);
return IRQ_HANDLED;
}
static struct irqaction omap2_gp_timer_irq = {
.name = "gp timer",
.flags = SA_INTERRUPT,
.handler = omap2_gp_timer_interrupt,
};
static void __init omap2_gp_timer_init(void)
{
struct clk * sys_ck;
u32 tick_period = 120000;
u32 l;
/* Reset clock and prescale value */
timer_write_reg(OS_TIMER_NR, GP_TIMER_TCLR, 0);
sys_ck = clk_get(NULL, "sys_ck");
if (IS_ERR(sys_ck))
printk(KERN_ERR "Could not get sys_ck\n");
else {
clk_use(sys_ck);
tick_period = clk_get_rate(sys_ck) / 100;
clk_put(sys_ck);
}
tick_period /= 2; /* Minimum prescale divider is 2 */
tick_period -= 1;
l = timer_read_reg(OS_TIMER_NR, GP_TIMER_TIDR);
printk(KERN_INFO "OMAP2 GP timer (HW version %d.%d)\n",
(l >> 4) & 0x0f, l & 0x0f);
setup_irq(38, &omap2_gp_timer_irq);
omap2_gp_timer_start(OS_TIMER_NR, tick_period);
}
struct sys_timer omap_timer = {
.init = omap2_gp_timer_init,
};
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