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/*
* linux/arch/h8300/kernel/cpu/timer/timer8.c
*
* Yoshinori Sato <ysato@users.sourcefoge.jp>
*
* 8bit Timer driver
*
*/
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/clockchips.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#define _8TCR 0
#define _8TCSR 2
#define TCORA 4
#define TCORB 6
#define _8TCNT 8
#define FLAG_STARTED (1 << 3)
#define SCALE 64
struct timer8_priv {
struct clock_event_device ced;
unsigned long mapbase;
unsigned long flags;
unsigned int rate;
unsigned int tcora;
};
static unsigned long timer8_get_counter(struct timer8_priv *p)
{
unsigned long v1, v2, v3;
int o1, o2;
o1 = ctrl_inb(p->mapbase + _8TCSR) & 0x20;
/* Make sure the timer value is stable. Stolen from acpi_pm.c */
do {
o2 = o1;
v1 = ctrl_inw(p->mapbase + _8TCNT);
v2 = ctrl_inw(p->mapbase + _8TCNT);
v3 = ctrl_inw(p->mapbase + _8TCNT);
o1 = ctrl_inb(p->mapbase + _8TCSR) & 0x20;
} while (unlikely((o1 != o2) || (v1 > v2 && v1 < v3)
|| (v2 > v3 && v2 < v1) || (v3 > v1 && v3 < v2)));
v2 |= o1 << 10;
return v2;
}
static irqreturn_t timer8_interrupt(int irq, void *dev_id)
{
struct timer8_priv *p = dev_id;
ctrl_outb(ctrl_inb(p->mapbase + _8TCSR) & ~0x40,
p->mapbase + _8TCSR);
ctrl_outw(p->tcora, p->mapbase + TCORA);
if (clockevent_state_oneshot(&p->ced))
ctrl_outw(0x0000, p->mapbase + _8TCR);
p->ced.event_handler(&p->ced);
return IRQ_HANDLED;
}
static void timer8_set_next(struct timer8_priv *p, unsigned long delta)
{
unsigned long now;
if (delta >= 0x10000)
pr_warn("delta out of range\n");
now = timer8_get_counter(p);
p->tcora = delta;
ctrl_outb(ctrl_inb(p->mapbase + _8TCR) | 0x40, p->mapbase + _8TCR);
if (delta > now)
ctrl_outw(delta, p->mapbase + TCORA);
else
ctrl_outw(now + 1, p->mapbase + TCORA);
}
static int timer8_enable(struct timer8_priv *p)
{
ctrl_outw(0xffff, p->mapbase + TCORA);
ctrl_outw(0x0000, p->mapbase + _8TCNT);
ctrl_outw(0x0c02, p->mapbase + _8TCR);
return 0;
}
static int timer8_start(struct timer8_priv *p)
{
int ret;
if ((p->flags & FLAG_STARTED))
return 0;
ret = timer8_enable(p);
if (!ret)
p->flags |= FLAG_STARTED;
return ret;
}
static void timer8_stop(struct timer8_priv *p)
{
ctrl_outw(0x0000, p->mapbase + _8TCR);
}
static inline struct timer8_priv *ced_to_priv(struct clock_event_device *ced)
{
return container_of(ced, struct timer8_priv, ced);
}
static void timer8_clock_event_start(struct timer8_priv *p, unsigned long delta)
{
struct clock_event_device *ced = &p->ced;
timer8_start(p);
ced->shift = 32;
ced->mult = div_sc(p->rate, NSEC_PER_SEC, ced->shift);
ced->max_delta_ns = clockevent_delta2ns(0xffff, ced);
ced->min_delta_ns = clockevent_delta2ns(0x0001, ced);
timer8_set_next(p, delta);
}
static int timer8_clock_event_shutdown(struct clock_event_device *ced)
{
timer8_stop(ced_to_priv(ced));
return 0;
}
static int timer8_clock_event_periodic(struct clock_event_device *ced)
{
struct timer8_priv *p = ced_to_priv(ced);
pr_info("%s: used for periodic clock events\n", ced->name);
timer8_stop(p);
timer8_clock_event_start(p, (p->rate + HZ/2) / HZ);
return 0;
}
static int timer8_clock_event_oneshot(struct clock_event_device *ced)
{
struct timer8_priv *p = ced_to_priv(ced);
pr_info("%s: used for oneshot clock events\n", ced->name);
timer8_stop(p);
timer8_clock_event_start(p, 0x10000);
return 0;
}
static int timer8_clock_event_next(unsigned long delta,
struct clock_event_device *ced)
{
struct timer8_priv *p = ced_to_priv(ced);
BUG_ON(!clockevent_state_oneshot(ced));
timer8_set_next(p, delta - 1);
return 0;
}
static struct timer8_priv timer8_priv = {
.ced = {
.name = "h8300_8timer",
.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
.rating = 200,
.set_next_event = timer8_clock_event_next,
.set_state_shutdown = timer8_clock_event_shutdown,
.set_state_periodic = timer8_clock_event_periodic,
.set_state_oneshot = timer8_clock_event_oneshot,
},
};
static void __init h8300_8timer_init(struct device_node *node)
{
void __iomem *base;
int irq;
int ret = 0;
int rate;
struct clk *clk;
clk = of_clk_get(node, 0);
if (IS_ERR(clk)) {
pr_err("failed to get clock for clockevent\n");
return;
}
base = of_iomap(node, 0);
if (!base) {
pr_err("failed to map registers for clockevent\n");
goto free_clk;
}
irq = irq_of_parse_and_map(node, 0);
if (!irq) {
pr_err("failed to get irq for clockevent\n");
goto unmap_reg;
}
timer8_priv.mapbase = (unsigned long)base;
rate = clk_get_rate(clk) / SCALE;
if (!rate) {
pr_err("Failed to get rate for the clocksource\n");
goto unmap_reg;
}
ret = request_irq(irq, timer8_interrupt,
IRQF_TIMER, timer8_priv.ced.name, &timer8_priv);
if (ret < 0) {
pr_err("failed to request irq %d for clockevent\n", irq);
goto unmap_reg;
}
clockevents_config_and_register(&timer8_priv.ced, rate, 1, 0x0000ffff);
return;
unmap_reg:
iounmap(base);
free_clk:
clk_put(clk);
}
CLOCKSOURCE_OF_DECLARE(h8300_8bit, "renesas,8bit-timer", h8300_8timer_init);
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