linux/drivers/clocksource/timer-sun5i.c

344 lines
8.8 KiB
C

/*
* Allwinner SoCs hstimer driver.
*
* Copyright (C) 2013 Maxime Ripard
*
* Maxime Ripard <maxime.ripard@free-electrons.com>
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*/
#include <linux/clk.h>
#include <linux/clockchips.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/irqreturn.h>
#include <linux/reset.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#define TIMER_IRQ_EN_REG 0x00
#define TIMER_IRQ_EN(val) BIT(val)
#define TIMER_IRQ_ST_REG 0x04
#define TIMER_CTL_REG(val) (0x20 * (val) + 0x10)
#define TIMER_CTL_ENABLE BIT(0)
#define TIMER_CTL_RELOAD BIT(1)
#define TIMER_CTL_CLK_PRES(val) (((val) & 0x7) << 4)
#define TIMER_CTL_ONESHOT BIT(7)
#define TIMER_INTVAL_LO_REG(val) (0x20 * (val) + 0x14)
#define TIMER_INTVAL_HI_REG(val) (0x20 * (val) + 0x18)
#define TIMER_CNTVAL_LO_REG(val) (0x20 * (val) + 0x1c)
#define TIMER_CNTVAL_HI_REG(val) (0x20 * (val) + 0x20)
#define TIMER_SYNC_TICKS 3
struct sun5i_timer {
void __iomem *base;
struct clk *clk;
struct notifier_block clk_rate_cb;
u32 ticks_per_jiffy;
};
#define to_sun5i_timer(x) \
container_of(x, struct sun5i_timer, clk_rate_cb)
struct sun5i_timer_clksrc {
struct sun5i_timer timer;
struct clocksource clksrc;
};
#define to_sun5i_timer_clksrc(x) \
container_of(x, struct sun5i_timer_clksrc, clksrc)
struct sun5i_timer_clkevt {
struct sun5i_timer timer;
struct clock_event_device clkevt;
};
#define to_sun5i_timer_clkevt(x) \
container_of(x, struct sun5i_timer_clkevt, clkevt)
/*
* When we disable a timer, we need to wait at least for 2 cycles of
* the timer source clock. We will use for that the clocksource timer
* that is already setup and runs at the same frequency than the other
* timers, and we never will be disabled.
*/
static void sun5i_clkevt_sync(struct sun5i_timer_clkevt *ce)
{
u32 old = readl(ce->timer.base + TIMER_CNTVAL_LO_REG(1));
while ((old - readl(ce->timer.base + TIMER_CNTVAL_LO_REG(1))) < TIMER_SYNC_TICKS)
cpu_relax();
}
static void sun5i_clkevt_time_stop(struct sun5i_timer_clkevt *ce, u8 timer)
{
u32 val = readl(ce->timer.base + TIMER_CTL_REG(timer));
writel(val & ~TIMER_CTL_ENABLE, ce->timer.base + TIMER_CTL_REG(timer));
sun5i_clkevt_sync(ce);
}
static void sun5i_clkevt_time_setup(struct sun5i_timer_clkevt *ce, u8 timer, u32 delay)
{
writel(delay, ce->timer.base + TIMER_INTVAL_LO_REG(timer));
}
static void sun5i_clkevt_time_start(struct sun5i_timer_clkevt *ce, u8 timer, bool periodic)
{
u32 val = readl(ce->timer.base + TIMER_CTL_REG(timer));
if (periodic)
val &= ~TIMER_CTL_ONESHOT;
else
val |= TIMER_CTL_ONESHOT;
writel(val | TIMER_CTL_ENABLE | TIMER_CTL_RELOAD,
ce->timer.base + TIMER_CTL_REG(timer));
}
static int sun5i_clkevt_shutdown(struct clock_event_device *clkevt)
{
struct sun5i_timer_clkevt *ce = to_sun5i_timer_clkevt(clkevt);
sun5i_clkevt_time_stop(ce, 0);
return 0;
}
static int sun5i_clkevt_set_oneshot(struct clock_event_device *clkevt)
{
struct sun5i_timer_clkevt *ce = to_sun5i_timer_clkevt(clkevt);
sun5i_clkevt_time_stop(ce, 0);
sun5i_clkevt_time_start(ce, 0, false);
return 0;
}
static int sun5i_clkevt_set_periodic(struct clock_event_device *clkevt)
{
struct sun5i_timer_clkevt *ce = to_sun5i_timer_clkevt(clkevt);
sun5i_clkevt_time_stop(ce, 0);
sun5i_clkevt_time_setup(ce, 0, ce->timer.ticks_per_jiffy);
sun5i_clkevt_time_start(ce, 0, true);
return 0;
}
static int sun5i_clkevt_next_event(unsigned long evt,
struct clock_event_device *clkevt)
{
struct sun5i_timer_clkevt *ce = to_sun5i_timer_clkevt(clkevt);
sun5i_clkevt_time_stop(ce, 0);
sun5i_clkevt_time_setup(ce, 0, evt - TIMER_SYNC_TICKS);
sun5i_clkevt_time_start(ce, 0, false);
return 0;
}
static irqreturn_t sun5i_timer_interrupt(int irq, void *dev_id)
{
struct sun5i_timer_clkevt *ce = (struct sun5i_timer_clkevt *)dev_id;
writel(0x1, ce->timer.base + TIMER_IRQ_ST_REG);
ce->clkevt.event_handler(&ce->clkevt);
return IRQ_HANDLED;
}
static int sun5i_rate_cb_clksrc(struct notifier_block *nb,
unsigned long event, void *data)
{
struct clk_notifier_data *ndata = data;
struct sun5i_timer *timer = to_sun5i_timer(nb);
struct sun5i_timer_clksrc *cs = container_of(timer, struct sun5i_timer_clksrc, timer);
switch (event) {
case PRE_RATE_CHANGE:
clocksource_unregister(&cs->clksrc);
break;
case POST_RATE_CHANGE:
clocksource_register_hz(&cs->clksrc, ndata->new_rate);
break;
default:
break;
}
return NOTIFY_DONE;
}
static int __init sun5i_setup_clocksource(struct device_node *node,
void __iomem *base,
struct clk *clk, int irq)
{
struct sun5i_timer_clksrc *cs;
unsigned long rate;
int ret;
cs = kzalloc(sizeof(*cs), GFP_KERNEL);
if (!cs)
return -ENOMEM;
ret = clk_prepare_enable(clk);
if (ret) {
pr_err("Couldn't enable parent clock\n");
goto err_free;
}
rate = clk_get_rate(clk);
cs->timer.base = base;
cs->timer.clk = clk;
cs->timer.clk_rate_cb.notifier_call = sun5i_rate_cb_clksrc;
cs->timer.clk_rate_cb.next = NULL;
ret = clk_notifier_register(clk, &cs->timer.clk_rate_cb);
if (ret) {
pr_err("Unable to register clock notifier.\n");
goto err_disable_clk;
}
writel(~0, base + TIMER_INTVAL_LO_REG(1));
writel(TIMER_CTL_ENABLE | TIMER_CTL_RELOAD,
base + TIMER_CTL_REG(1));
ret = clocksource_mmio_init(base + TIMER_CNTVAL_LO_REG(1), node->name,
rate, 340, 32, clocksource_mmio_readl_down);
if (ret) {
pr_err("Couldn't register clock source.\n");
goto err_remove_notifier;
}
return 0;
err_remove_notifier:
clk_notifier_unregister(clk, &cs->timer.clk_rate_cb);
err_disable_clk:
clk_disable_unprepare(clk);
err_free:
kfree(cs);
return ret;
}
static int sun5i_rate_cb_clkevt(struct notifier_block *nb,
unsigned long event, void *data)
{
struct clk_notifier_data *ndata = data;
struct sun5i_timer *timer = to_sun5i_timer(nb);
struct sun5i_timer_clkevt *ce = container_of(timer, struct sun5i_timer_clkevt, timer);
if (event == POST_RATE_CHANGE) {
clockevents_update_freq(&ce->clkevt, ndata->new_rate);
ce->timer.ticks_per_jiffy = DIV_ROUND_UP(ndata->new_rate, HZ);
}
return NOTIFY_DONE;
}
static int __init sun5i_setup_clockevent(struct device_node *node, void __iomem *base,
struct clk *clk, int irq)
{
struct sun5i_timer_clkevt *ce;
unsigned long rate;
int ret;
u32 val;
ce = kzalloc(sizeof(*ce), GFP_KERNEL);
if (!ce)
return -ENOMEM;
ret = clk_prepare_enable(clk);
if (ret) {
pr_err("Couldn't enable parent clock\n");
goto err_free;
}
rate = clk_get_rate(clk);
ce->timer.base = base;
ce->timer.ticks_per_jiffy = DIV_ROUND_UP(rate, HZ);
ce->timer.clk = clk;
ce->timer.clk_rate_cb.notifier_call = sun5i_rate_cb_clkevt;
ce->timer.clk_rate_cb.next = NULL;
ret = clk_notifier_register(clk, &ce->timer.clk_rate_cb);
if (ret) {
pr_err("Unable to register clock notifier.\n");
goto err_disable_clk;
}
ce->clkevt.name = node->name;
ce->clkevt.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
ce->clkevt.set_next_event = sun5i_clkevt_next_event;
ce->clkevt.set_state_shutdown = sun5i_clkevt_shutdown;
ce->clkevt.set_state_periodic = sun5i_clkevt_set_periodic;
ce->clkevt.set_state_oneshot = sun5i_clkevt_set_oneshot;
ce->clkevt.tick_resume = sun5i_clkevt_shutdown;
ce->clkevt.rating = 340;
ce->clkevt.irq = irq;
ce->clkevt.cpumask = cpu_possible_mask;
/* Enable timer0 interrupt */
val = readl(base + TIMER_IRQ_EN_REG);
writel(val | TIMER_IRQ_EN(0), base + TIMER_IRQ_EN_REG);
clockevents_config_and_register(&ce->clkevt, rate,
TIMER_SYNC_TICKS, 0xffffffff);
ret = request_irq(irq, sun5i_timer_interrupt, IRQF_TIMER | IRQF_IRQPOLL,
"sun5i_timer0", ce);
if (ret) {
pr_err("Unable to register interrupt\n");
goto err_remove_notifier;
}
return 0;
err_remove_notifier:
clk_notifier_unregister(clk, &ce->timer.clk_rate_cb);
err_disable_clk:
clk_disable_unprepare(clk);
err_free:
kfree(ce);
return ret;
}
static void __init sun5i_timer_init(struct device_node *node)
{
struct reset_control *rstc;
void __iomem *timer_base;
struct clk *clk;
int irq;
timer_base = of_io_request_and_map(node, 0, of_node_full_name(node));
if (IS_ERR(timer_base))
panic("Can't map registers");
irq = irq_of_parse_and_map(node, 0);
if (irq <= 0)
panic("Can't parse IRQ");
clk = of_clk_get(node, 0);
if (IS_ERR(clk))
panic("Can't get timer clock");
rstc = of_reset_control_get(node, NULL);
if (!IS_ERR(rstc))
reset_control_deassert(rstc);
sun5i_setup_clocksource(node, timer_base, clk, irq);
sun5i_setup_clockevent(node, timer_base, clk, irq);
}
CLOCKSOURCE_OF_DECLARE(sun5i_a13, "allwinner,sun5i-a13-hstimer",
sun5i_timer_init);
CLOCKSOURCE_OF_DECLARE(sun7i_a20, "allwinner,sun7i-a20-hstimer",
sun5i_timer_init);