mirror of
git://projects.qi-hardware.com/openwrt-xburst.git
synced 2024-12-12 03:26:15 +02:00
140306fae8
We don't support disabling the clock, but this is actually what it would do. Signed-off-by: Florian Fainelli <florian@openwrt.org> git-svn-id: svn://svn.openwrt.org/openwrt/trunk@34394 3c298f89-4303-0410-b956-a3cf2f4a3e73
136 lines
3.2 KiB
C
136 lines
3.2 KiB
C
/*
|
|
* Moschip MCS814x timer routines
|
|
*
|
|
* Copyright (C) 2012, Florian Fainelli <florian@openwrt.org>
|
|
*
|
|
* Licensed under GPLv2
|
|
*/
|
|
#include <linux/kernel.h>
|
|
#include <linux/interrupt.h>
|
|
#include <linux/time.h>
|
|
#include <linux/timex.h>
|
|
#include <linux/irq.h>
|
|
#include <linux/err.h>
|
|
#include <linux/clk.h>
|
|
#include <linux/io.h>
|
|
#include <linux/of.h>
|
|
#include <linux/of_address.h>
|
|
|
|
#include <asm/mach/time.h>
|
|
#include <mach/mcs814x.h>
|
|
|
|
/* Timer block registers */
|
|
#define TIMER_VAL 0x00
|
|
#define TIMER_CTL 0x04
|
|
#define TIMER_CTL_EN 0x01
|
|
#define TIMER_CTL_DBG 0x02
|
|
|
|
static u32 last_reload;
|
|
static u32 timer_correct;
|
|
static u32 clock_rate;
|
|
static u32 timer_reload_value;
|
|
static void __iomem *mcs814x_timer_base;
|
|
|
|
static inline unsigned long ticks2usecs(u32 x)
|
|
{
|
|
return x / (clock_rate / 1000000);
|
|
}
|
|
|
|
/*
|
|
* Returns number of ms since last clock interrupt. Note that interrupts
|
|
* will have been disabled by do_gettimeoffset()
|
|
*/
|
|
static unsigned long mcs814x_gettimeoffset(void)
|
|
{
|
|
u32 ticks = readl_relaxed(mcs814x_timer_base + TIMER_VAL);
|
|
|
|
if (ticks < last_reload)
|
|
return ticks2usecs(ticks + (u32)(0xffffffff - last_reload));
|
|
else
|
|
return ticks2usecs(ticks - last_reload);
|
|
}
|
|
|
|
|
|
static irqreturn_t mcs814x_timer_interrupt(int irq, void *dev_id)
|
|
{
|
|
u32 count = readl_relaxed(mcs814x_timer_base + TIMER_VAL);
|
|
|
|
/* take into account delay up to this moment */
|
|
last_reload = count + timer_correct + timer_reload_value;
|
|
|
|
if (last_reload < timer_reload_value) {
|
|
last_reload = timer_reload_value;
|
|
} else {
|
|
if (timer_correct == 0)
|
|
timer_correct = readl_relaxed(mcs814x_timer_base + TIMER_VAL) - count;
|
|
}
|
|
writel_relaxed(last_reload, mcs814x_timer_base + TIMER_VAL);
|
|
|
|
timer_tick();
|
|
|
|
return IRQ_HANDLED;
|
|
}
|
|
|
|
static struct irqaction mcs814x_timer_irq = {
|
|
.name = "mcs814x-timer",
|
|
.flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
|
|
.handler = mcs814x_timer_interrupt,
|
|
};
|
|
|
|
static struct of_device_id mcs814x_timer_ids[] = {
|
|
{ .compatible = "moschip,mcs814x-timer" },
|
|
{ /* sentinel */ },
|
|
};
|
|
|
|
static void __init mcs814x_of_timer_init(void)
|
|
{
|
|
struct device_node *np;
|
|
const unsigned int *intspec;
|
|
|
|
np = of_find_matching_node(NULL, mcs814x_timer_ids);
|
|
if (!np)
|
|
panic("unable to find compatible timer node in dtb");
|
|
|
|
mcs814x_timer_base = of_iomap(np, 0);
|
|
if (!mcs814x_timer_base)
|
|
panic("unable to remap timer cpu registers");
|
|
|
|
intspec = of_get_property(np, "interrupts", NULL);
|
|
if (!intspec)
|
|
panic("no interrupts property for timer");
|
|
|
|
mcs814x_timer_irq.irq = be32_to_cpup(intspec);
|
|
}
|
|
|
|
static void __init mcs814x_timer_init(void)
|
|
{
|
|
struct clk *clk;
|
|
|
|
clk = clk_get_sys("timer0", NULL);
|
|
if (IS_ERR_OR_NULL(clk))
|
|
panic("unable to get timer0 clock");
|
|
|
|
clock_rate = clk_get_rate(clk);
|
|
|
|
mcs814x_of_timer_init();
|
|
|
|
pr_info("Timer frequency: %d (kHz)\n", clock_rate / 1000);
|
|
|
|
timer_reload_value = 0xffffffff - (clock_rate / HZ);
|
|
|
|
/* disable timer */
|
|
writel_relaxed(~TIMER_CTL_EN, mcs814x_timer_base + TIMER_CTL);
|
|
writel_relaxed(timer_reload_value, mcs814x_timer_base + TIMER_VAL);
|
|
last_reload = timer_reload_value;
|
|
|
|
setup_irq(mcs814x_timer_irq.irq, &mcs814x_timer_irq);
|
|
/* enable timer, stop timer in debug mode */
|
|
writel_relaxed(TIMER_CTL_EN | TIMER_CTL_DBG,
|
|
mcs814x_timer_base + TIMER_CTL);
|
|
}
|
|
|
|
struct sys_timer mcs814x_timer = {
|
|
.init = mcs814x_timer_init,
|
|
.offset = mcs814x_gettimeoffset,
|
|
};
|