linux/drivers/clocksource/h8300_timer8.c

319 lines
6.9 KiB
C

/*
* linux/arch/h8300/kernel/cpu/timer/timer8.c
*
* Yoshinori Sato <ysato@users.sourcefoge.jp>
*
* 8bit Timer driver
*
*/
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/clockchips.h>
#include <linux/module.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/of.h>
#include <asm/irq.h>
#define _8TCR 0
#define _8TCSR 2
#define TCORA 4
#define TCORB 6
#define _8TCNT 8
#define FLAG_REPROGRAM (1 << 0)
#define FLAG_SKIPEVENT (1 << 1)
#define FLAG_IRQCONTEXT (1 << 2)
#define FLAG_STARTED (1 << 3)
#define ONESHOT 0
#define PERIODIC 1
#define RELATIVE 0
#define ABSOLUTE 1
struct timer8_priv {
struct platform_device *pdev;
struct clock_event_device ced;
struct irqaction irqaction;
unsigned long mapbase;
raw_spinlock_t lock;
unsigned long flags;
unsigned int rate;
unsigned int tcora;
struct clk *pclk;
};
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);
p->flags |= FLAG_IRQCONTEXT;
ctrl_outw(p->tcora, p->mapbase + TCORA);
if (!(p->flags & FLAG_SKIPEVENT)) {
if (clockevent_state_oneshot(&p->ced))
ctrl_outw(0x0000, p->mapbase + _8TCR);
p->ced.event_handler(&p->ced);
}
p->flags &= ~(FLAG_SKIPEVENT | FLAG_IRQCONTEXT);
return IRQ_HANDLED;
}
static void timer8_set_next(struct timer8_priv *p, unsigned long delta)
{
unsigned long flags;
unsigned long now;
raw_spin_lock_irqsave(&p->lock, flags);
if (delta >= 0x10000)
dev_warn(&p->pdev->dev, "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);
raw_spin_unlock_irqrestore(&p->lock, flags);
}
static int timer8_enable(struct timer8_priv *p)
{
p->rate = clk_get_rate(p->pclk) / 64;
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 = 0;
unsigned long flags;
raw_spin_lock_irqsave(&p->lock, flags);
if (!(p->flags & FLAG_STARTED))
ret = timer8_enable(p);
if (ret)
goto out;
p->flags |= FLAG_STARTED;
out:
raw_spin_unlock_irqrestore(&p->lock, flags);
return ret;
}
static void timer8_stop(struct timer8_priv *p)
{
unsigned long flags;
raw_spin_lock_irqsave(&p->lock, flags);
ctrl_outw(0x0000, p->mapbase + _8TCR);
raw_spin_unlock_irqrestore(&p->lock, flags);
}
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, int periodic)
{
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, periodic?(p->rate + HZ/2) / HZ:0x10000);
}
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);
dev_info(&p->pdev->dev, "used for periodic clock events\n");
timer8_stop(p);
timer8_clock_event_start(p, PERIODIC);
return 0;
}
static int timer8_clock_event_oneshot(struct clock_event_device *ced)
{
struct timer8_priv *p = ced_to_priv(ced);
dev_info(&p->pdev->dev, "used for oneshot clock events\n");
timer8_stop(p);
timer8_clock_event_start(p, ONESHOT);
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 int timer8_setup(struct timer8_priv *p,
struct platform_device *pdev)
{
struct resource *res;
int irq;
int ret;
memset(p, 0, sizeof(*p));
p->pdev = pdev;
res = platform_get_resource(p->pdev, IORESOURCE_MEM, 0);
if (!res) {
dev_err(&p->pdev->dev, "failed to get I/O memory\n");
return -ENXIO;
}
irq = platform_get_irq(p->pdev, 0);
if (irq < 0) {
dev_err(&p->pdev->dev, "failed to get irq\n");
return -ENXIO;
}
p->mapbase = res->start;
p->irqaction.name = dev_name(&p->pdev->dev);
p->irqaction.handler = timer8_interrupt;
p->irqaction.dev_id = p;
p->irqaction.flags = IRQF_TIMER;
p->pclk = clk_get(&p->pdev->dev, "fck");
if (IS_ERR(p->pclk)) {
dev_err(&p->pdev->dev, "can't get clk\n");
return PTR_ERR(p->pclk);
}
p->ced.name = pdev->name;
p->ced.features = CLOCK_EVT_FEAT_PERIODIC |
CLOCK_EVT_FEAT_ONESHOT;
p->ced.rating = 200;
p->ced.cpumask = cpumask_of(0);
p->ced.set_next_event = timer8_clock_event_next;
p->ced.set_state_shutdown = timer8_clock_event_shutdown;
p->ced.set_state_periodic = timer8_clock_event_periodic;
p->ced.set_state_oneshot = timer8_clock_event_oneshot;
ret = setup_irq(irq, &p->irqaction);
if (ret < 0) {
dev_err(&p->pdev->dev,
"failed to request irq %d\n", irq);
return ret;
}
clockevents_register_device(&p->ced);
platform_set_drvdata(pdev, p);
return 0;
}
static int timer8_probe(struct platform_device *pdev)
{
struct timer8_priv *p = platform_get_drvdata(pdev);
if (p) {
dev_info(&pdev->dev, "kept as earlytimer\n");
return 0;
}
p = devm_kzalloc(&pdev->dev, sizeof(*p), GFP_KERNEL);
if (!p)
return -ENOMEM;
return timer8_setup(p, pdev);
}
static int timer8_remove(struct platform_device *pdev)
{
return -EBUSY;
}
static const struct of_device_id timer8_of_table[] __maybe_unused = {
{ .compatible = "renesas,8bit-timer" },
{ }
};
MODULE_DEVICE_TABLE(of, timer8_of_table);
static struct platform_driver timer8_driver = {
.probe = timer8_probe,
.remove = timer8_remove,
.driver = {
.name = "h8300-8timer",
.of_match_table = of_match_ptr(timer8_of_table),
}
};
static int __init timer8_init(void)
{
return platform_driver_register(&timer8_driver);
}
static void __exit timer8_exit(void)
{
platform_driver_unregister(&timer8_driver);
}
subsys_initcall(timer8_init);
module_exit(timer8_exit);
MODULE_AUTHOR("Yoshinori Sato");
MODULE_DESCRIPTION("H8/300 8bit Timer Driver");
MODULE_LICENSE("GPL v2");