/*
* Amlogic Meson6 SoCs timer handling.
*
* Copyright (C) 2014 Carlo Caione <carlo@caione.org>
*
* Based on code from Amlogic, Inc
*
* 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/interrupt.h>
#include <linux/irq.h>
#include <linux/irqreturn.h>
#include <linux/sched_clock.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#define CED_ID 0
#define CSD_ID 4
#define TIMER_ISA_MUX 0
#define TIMER_ISA_VAL(t) (((t) + 1) << 2)
#define TIMER_INPUT_BIT(t) (2 * (t))
#define TIMER_ENABLE_BIT(t) (16 + (t))
#define TIMER_PERIODIC_BIT(t) (12 + (t))
#define TIMER_CED_INPUT_MASK (3UL << TIMER_INPUT_BIT(CED_ID))
#define TIMER_CSD_INPUT_MASK (7UL << TIMER_INPUT_BIT(CSD_ID))
#define TIMER_CED_UNIT_1US 0
#define TIMER_CSD_UNIT_1US 1
static void __iomem *timer_base;
static u64 notrace meson6_timer_sched_read(void)
{
return (u64)readl(timer_base + TIMER_ISA_VAL(CSD_ID));
}
static void meson6_clkevt_time_stop(unsigned char timer)
{
u32 val = readl(timer_base + TIMER_ISA_MUX);
writel(val & ~TIMER_ENABLE_BIT(timer), timer_base + TIMER_ISA_MUX);
}
static void meson6_clkevt_time_setup(unsigned char timer, unsigned long delay)
{
writel(delay, timer_base + TIMER_ISA_VAL(timer));
}
static void meson6_clkevt_time_start(unsigned char timer, bool periodic)
{
u32 val = readl(timer_base + TIMER_ISA_MUX);
if (periodic)
val |= TIMER_PERIODIC_BIT(timer);
else
val &= ~TIMER_PERIODIC_BIT(timer);
writel(val | TIMER_ENABLE_BIT(timer), timer_base + TIMER_ISA_MUX);
}
static void meson6_clkevt_mode(enum clock_event_mode mode,
struct clock_event_device *clk)
{
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
meson6_clkevt_time_stop(CED_ID);
meson6_clkevt_time_setup(CED_ID, USEC_PER_SEC/HZ - 1);
meson6_clkevt_time_start(CED_ID, true);
break;
case CLOCK_EVT_MODE_ONESHOT:
meson6_clkevt_time_stop(CED_ID);
meson6_clkevt_time_start(CED_ID, false);
break;
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_SHUTDOWN:
default:
meson6_clkevt_time_stop(CED_ID);
break;
}
}
static int meson6_clkevt_next_event(unsigned long evt,
struct clock_event_device *unused)
{
meson6_clkevt_time_stop(CED_ID);
meson6_clkevt_time_setup(CED_ID, evt);
meson6_clkevt_time_start(CED_ID, false);
return 0;
}
static struct clock_event_device meson6_clockevent = {
.name = "meson6_tick",
.rating = 400,
.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
.set_mode = meson6_clkevt_mode,
.set_next_event = meson6_clkevt_next_event,
};
static irqreturn_t meson6_timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evt = (struct clock_event_device *)dev_id;
evt->event_handler(evt);
return IRQ_HANDLED;
}
static struct irqaction meson6_timer_irq = {
.name = "meson6_timer",
.flags = IRQF_TIMER | IRQF_IRQPOLL,
.handler = meson6_timer_interrupt,
.dev_id = &meson6_clockevent,
};
static void __init meson6_timer_init(struct device_node *node)
{
u32 val;
int ret, irq;
timer_base = of_io_request_and_map(node, 0, "meson6-timer");
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");
/* Set 1us for timer E */
val = readl(timer_base + TIMER_ISA_MUX);
val &= ~TIMER_CSD_INPUT_MASK;
val |= TIMER_CSD_UNIT_1US << TIMER_INPUT_BIT(CSD_ID);
writel(val, timer_base + TIMER_ISA_MUX);
sched_clock_register(meson6_timer_sched_read, 32, USEC_PER_SEC);
clocksource_mmio_init(timer_base + TIMER_ISA_VAL(CSD_ID), node->name,
1000 * 1000, 300, 32, clocksource_mmio_readl_up);
/* Timer A base 1us */
val &= ~TIMER_CED_INPUT_MASK;
val |= TIMER_CED_UNIT_1US << TIMER_INPUT_BIT(CED_ID);
writel(val, timer_base + TIMER_ISA_MUX);
/* Stop the timer A */
meson6_clkevt_time_stop(CED_ID);
ret = setup_irq(irq, &meson6_timer_irq);
if (ret)
pr_warn("failed to setup irq %d\n", irq);
meson6_clockevent.cpumask = cpu_possible_mask;
meson6_clockevent.irq = irq;
clockevents_config_and_register(&meson6_clockevent, USEC_PER_SEC,
1, 0xfffe);
}
CLOCKSOURCE_OF_DECLARE(meson6, "amlogic,meson6-timer",
meson6_timer_init);
