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/*
* arch/arm/mach-ep93xx/core.c
* Core routines for Cirrus EP93xx chips.
*
* Copyright (C) 2006 Lennert Buytenhek <buytenh@wantstofly.org>
*
* Thanks go to Michael Burian and Ray Lehtiniemi for their key
* role in the ep93xx linux community.
*
* 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/config.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/serial.h>
#include <linux/tty.h>
#include <linux/bitops.h>
#include <linux/serial.h>
#include <linux/serial_8250.h>
#include <linux/serial_core.h>
#include <linux/device.h>
#include <linux/mm.h>
#include <linux/time.h>
#include <linux/timex.h>
#include <linux/delay.h>
#include <linux/amba/bus.h>
#include <asm/types.h>
#include <asm/setup.h>
#include <asm/memory.h>
#include <asm/hardware.h>
#include <asm/irq.h>
#include <asm/system.h>
#include <asm/tlbflush.h>
#include <asm/pgtable.h>
#include <asm/io.h>
#include <asm/mach/map.h>
#include <asm/mach/time.h>
#include <asm/mach/irq.h>
#include <asm/hardware/vic.h>
/*************************************************************************
* Static I/O mappings that are needed for all EP93xx platforms
*************************************************************************/
static struct map_desc ep93xx_io_desc[] __initdata = {
{
.virtual = EP93XX_AHB_VIRT_BASE,
.pfn = __phys_to_pfn(EP93XX_AHB_PHYS_BASE),
.length = EP93XX_AHB_SIZE,
.type = MT_DEVICE,
}, {
.virtual = EP93XX_APB_VIRT_BASE,
.pfn = __phys_to_pfn(EP93XX_APB_PHYS_BASE),
.length = EP93XX_APB_SIZE,
.type = MT_DEVICE,
},
};
void __init ep93xx_map_io(void)
{
iotable_init(ep93xx_io_desc, ARRAY_SIZE(ep93xx_io_desc));
}
/*************************************************************************
* Timer handling for EP93xx
*************************************************************************
* The ep93xx has four internal timers. Timers 1, 2 (both 16 bit) and
* 3 (32 bit) count down at 508 kHz, are self-reloading, and can generate
* an interrupt on underflow. Timer 4 (40 bit) counts down at 983.04 kHz,
* is free-running, and can't generate interrupts.
*
* The 508 kHz timers are ideal for use for the timer interrupt, as the
* most common values of HZ divide 508 kHz nicely. We pick one of the 16
* bit timers (timer 1) since we don't need more than 16 bits of reload
* value as long as HZ >= 8.
*
* The higher clock rate of timer 4 makes it a better choice than the
* other timers for use in gettimeoffset(), while the fact that it can't
* generate interrupts means we don't have to worry about not being able
* to use this timer for something else. We also use timer 4 for keeping
* track of lost jiffies.
*/
static unsigned int last_jiffy_time;
#define TIMER4_TICKS_PER_JIFFY ((CLOCK_TICK_RATE + (HZ/2)) / HZ)
static int ep93xx_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
write_seqlock(&xtime_lock);
__raw_writel(1, EP93XX_TIMER1_CLEAR);
while (__raw_readl(EP93XX_TIMER4_VALUE_LOW) - last_jiffy_time
>= TIMER4_TICKS_PER_JIFFY) {
last_jiffy_time += TIMER4_TICKS_PER_JIFFY;
timer_tick(regs);
}
write_sequnlock(&xtime_lock);
return IRQ_HANDLED;
}
static struct irqaction ep93xx_timer_irq = {
.name = "ep93xx timer",
.flags = SA_INTERRUPT | SA_TIMER,
.handler = ep93xx_timer_interrupt,
};
static void __init ep93xx_timer_init(void)
{
/* Enable periodic HZ timer. */
__raw_writel(0x48, EP93XX_TIMER1_CONTROL);
__raw_writel((508000 / HZ) - 1, EP93XX_TIMER1_LOAD);
__raw_writel(0xc8, EP93XX_TIMER1_CONTROL);
/* Enable lost jiffy timer. */
__raw_writel(0x100, EP93XX_TIMER4_VALUE_HIGH);
setup_irq(IRQ_EP93XX_TIMER1, &ep93xx_timer_irq);
}
static unsigned long ep93xx_gettimeoffset(void)
{
int offset;
offset = __raw_readl(EP93XX_TIMER4_VALUE_LOW) - last_jiffy_time;
/* Calculate (1000000 / 983040) * offset. */
return offset + (53 * offset / 3072);
}
struct sys_timer ep93xx_timer = {
.init = ep93xx_timer_init,
.offset = ep93xx_gettimeoffset,
};
/*************************************************************************
* EP93xx IRQ handling
*************************************************************************/
void __init ep93xx_init_irq(void)
{
vic_init((void *)EP93XX_VIC1_BASE, 0, EP93XX_VIC1_VALID_IRQ_MASK);
vic_init((void *)EP93XX_VIC2_BASE, 32, EP93XX_VIC2_VALID_IRQ_MASK);
}
/*************************************************************************
* EP93xx peripheral handling
*************************************************************************/
void __init ep93xx_init_devices(void)
{
unsigned int v;
/*
* Disallow access to MaverickCrunch initially.
*/
v = __raw_readl(EP93XX_SYSCON_DEVICE_CONFIG);
v &= ~EP93XX_SYSCON_DEVICE_CONFIG_CRUNCH_ENABLE;
__raw_writel(0xaa, EP93XX_SYSCON_SWLOCK);
__raw_writel(v, EP93XX_SYSCON_DEVICE_CONFIG);
}
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