/*
* Faraday Technology FTTMR010 timer driver
* Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
*
* Based on a rewrite of arch/arm/mach-gemini/timer.c:
* Copyright (C) 2001-2006 Storlink, Corp.
* Copyright (C) 2008-2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
*/
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/clockchips.h>
#include <linux/clocksource.h>
#include <linux/sched_clock.h>
#include <linux/clk.h>
#include <linux/slab.h>
/*
* Register definitions for the timers
*/
#define TIMER1_COUNT (0x00)
#define TIMER1_LOAD (0x04)
#define TIMER1_MATCH1 (0x08)
#define TIMER1_MATCH2 (0x0c)
#define TIMER2_COUNT (0x10)
#define TIMER2_LOAD (0x14)
#define TIMER2_MATCH1 (0x18)
#define TIMER2_MATCH2 (0x1c)
#define TIMER3_COUNT (0x20)
#define TIMER3_LOAD (0x24)
#define TIMER3_MATCH1 (0x28)
#define TIMER3_MATCH2 (0x2c)
#define TIMER_CR (0x30)
#define TIMER_INTR_STATE (0x34)
#define TIMER_INTR_MASK (0x38)
#define TIMER_1_CR_ENABLE (1 << 0)
#define TIMER_1_CR_CLOCK (1 << 1)
#define TIMER_1_CR_INT (1 << 2)
#define TIMER_2_CR_ENABLE (1 << 3)
#define TIMER_2_CR_CLOCK (1 << 4)
#define TIMER_2_CR_INT (1 << 5)
#define TIMER_3_CR_ENABLE (1 << 6)
#define TIMER_3_CR_CLOCK (1 << 7)
#define TIMER_3_CR_INT (1 << 8)
#define TIMER_1_CR_UPDOWN (1 << 9)
#define TIMER_2_CR_UPDOWN (1 << 10)
#define TIMER_3_CR_UPDOWN (1 << 11)
#define TIMER_DEFAULT_FLAGS (TIMER_1_CR_UPDOWN | \
TIMER_3_CR_ENABLE | \
TIMER_3_CR_UPDOWN)
#define TIMER_1_INT_MATCH1 (1 << 0)
#define TIMER_1_INT_MATCH2 (1 << 1)
#define TIMER_1_INT_OVERFLOW (1 << 2)
#define TIMER_2_INT_MATCH1 (1 << 3)
#define TIMER_2_INT_MATCH2 (1 << 4)
#define TIMER_2_INT_OVERFLOW (1 << 5)
#define TIMER_3_INT_MATCH1 (1 << 6)
#define TIMER_3_INT_MATCH2 (1 << 7)
#define TIMER_3_INT_OVERFLOW (1 << 8)
#define TIMER_INT_ALL_MASK 0x1ff
struct fttmr010 {
void __iomem *base;
unsigned int tick_rate;
struct clock_event_device clkevt;
};
/* A local singleton used by sched_clock, which is stateless */
static struct fttmr010 *local_fttmr;
static inline struct fttmr010 *to_fttmr010(struct clock_event_device *evt)
{
return container_of(evt, struct fttmr010, clkevt);
}
static u64 notrace fttmr010_read_sched_clock(void)
{
return readl(local_fttmr->base + TIMER3_COUNT);
}
static int fttmr010_timer_set_next_event(unsigned long cycles,
struct clock_event_device *evt)
{
struct fttmr010 *fttmr010 = to_fttmr010(evt);
u32 cr;
/* Setup the match register */
cr = readl(fttmr010->base + TIMER1_COUNT);
writel(cr + cycles, fttmr010->base + TIMER1_MATCH1);
if (readl(fttmr010->base + TIMER1_COUNT) - cr > cycles)
return -ETIME;
return 0;
}
static int fttmr010_timer_shutdown(struct clock_event_device *evt)
{
struct fttmr010 *fttmr010 = to_fttmr010(evt);
u32 cr;
/* Stop timer and interrupt. */
cr = readl(fttmr010->base + TIMER_CR);
cr &= ~(TIMER_1_CR_ENABLE | TIMER_1_CR_INT);
writel(cr, fttmr010->base + TIMER_CR);
return 0;
}
static int fttmr010_timer_set_oneshot(struct clock_event_device *evt)
{
struct fttmr010 *fttmr010 = to_fttmr010(evt);
u32 cr;
/* Stop timer and interrupt. */
cr = readl(fttmr010->base + TIMER_CR);
cr &= ~(TIMER_1_CR_ENABLE | TIMER_1_CR_INT);
writel(cr, fttmr010->base + TIMER_CR);
/* Setup counter start from 0 */
writel(0, fttmr010->base + TIMER1_COUNT);
writel(0, fttmr010->base + TIMER1_LOAD);
/* Enable interrupt */
cr = readl(fttmr010->base + TIMER_INTR_MASK);
cr &= ~(TIMER_1_INT_OVERFLOW | TIMER_1_INT_MATCH2);
cr |= TIMER_1_INT_MATCH1;
writel(cr, fttmr010->base + TIMER_INTR_MASK);
/* Start the timer */
cr = readl(fttmr010->base + TIMER_CR);
cr |= TIMER_1_CR_ENABLE;
writel(cr, fttmr010->base + TIMER_CR);
return 0;
}
static int fttmr010_timer_set_periodic(struct clock_event_device *evt)
{
struct fttmr010 *fttmr010 = to_fttmr010(evt);
u32 period = DIV_ROUND_CLOSEST(fttmr010->tick_rate, HZ);
u32 cr;
/* Stop timer and interrupt */
cr = readl(fttmr010->base + TIMER_CR);
cr &= ~(TIMER_1_CR_ENABLE | TIMER_1_CR_INT);
writel(cr, fttmr010->base + TIMER_CR);
/* Setup timer to fire at 1/HT intervals. */
cr = 0xffffffff - (period - 1);
writel(cr, fttmr010->base + TIMER1_COUNT);
writel(cr, fttmr010->base + TIMER1_LOAD);
/* enable interrupt on overflow */
cr = readl(fttmr010->base + TIMER_INTR_MASK);
cr &= ~(TIMER_1_INT_MATCH1 | TIMER_1_INT_MATCH2);
cr |= TIMER_1_INT_OVERFLOW;
writel(cr, fttmr010->base + TIMER_INTR_MASK);
/* Start the timer */
cr = readl(fttmr010->base + TIMER_CR);
cr |= TIMER_1_CR_ENABLE;
cr |= TIMER_1_CR_INT;
writel(cr, fttmr010->base + TIMER_CR);
return 0;
}
/*
* IRQ handler for the timer
*/
static irqreturn_t fttmr010_timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evt = dev_id;
evt->event_handler(evt);
return IRQ_HANDLED;
}
static int __init fttmr010_timer_init(struct device_node *np)
{
struct fttmr010 *fttmr010;
int irq;
struct clk *clk;
int ret;
/*
* These implementations require a clock reference.
* FIXME: we currently only support clocking using PCLK
* and using EXTCLK is not supported in the driver.
*/
clk = of_clk_get_by_name(np, "PCLK");
if (IS_ERR(clk)) {
pr_err("could not get PCLK\n");
return PTR_ERR(clk);
}
ret = clk_prepare_enable(clk);
if (ret) {
pr_err("failed to enable PCLK\n");
return ret;
}
fttmr010 = kzalloc(sizeof(*fttmr010), GFP_KERNEL);
if (!fttmr010) {
ret = -ENOMEM;
goto out_disable_clock;
}
fttmr010->tick_rate = clk_get_rate(clk);
fttmr010->base = of_iomap(np, 0);
if (!fttmr010->base) {
pr_err("Can't remap registers");
ret = -ENXIO;
goto out_free;
}
/* IRQ for timer 1 */
irq = irq_of_parse_and_map(np, 0);
if (irq <= 0) {
pr_err("Can't parse IRQ");
ret = -EINVAL;
goto out_unmap;
}
/*
* Reset the interrupt mask and status
*/
writel(TIMER_INT_ALL_MASK, fttmr010->base + TIMER_INTR_MASK);
writel(0, fttmr010->base + TIMER_INTR_STATE);
writel(TIMER_DEFAULT_FLAGS, fttmr010->base + TIMER_CR);
/*
* Setup free-running clocksource timer (interrupts
* disabled.)
*/
local_fttmr = fttmr010;
writel(0, fttmr010->base + TIMER3_COUNT);
writel(0, fttmr010->base + TIMER3_LOAD);
writel(0, fttmr010->base + TIMER3_MATCH1);
writel(0, fttmr010->base + TIMER3_MATCH2);
clocksource_mmio_init(fttmr010->base + TIMER3_COUNT,
"FTTMR010-TIMER3",
fttmr010->tick_rate,
300, 32, clocksource_mmio_readl_up);
sched_clock_register(fttmr010_read_sched_clock, 32,
fttmr010->tick_rate);
/*
* Setup clockevent timer (interrupt-driven) on timer 1.
*/
writel(0, fttmr010->base + TIMER1_COUNT);
writel(0, fttmr010->base + TIMER1_LOAD);
writel(0, fttmr010->base + TIMER1_MATCH1);
writel(0, fttmr010->base + TIMER1_MATCH2);
ret = request_irq(irq, fttmr010_timer_interrupt, IRQF_TIMER,
"FTTMR010-TIMER1", &fttmr010->clkevt);
if (ret) {
pr_err("FTTMR010-TIMER1 no IRQ\n");
goto out_unmap;
}
fttmr010->clkevt.name = "FTTMR010-TIMER1";
/* Reasonably fast and accurate clock event */
fttmr010->clkevt.rating = 300;
fttmr010->clkevt.features = CLOCK_EVT_FEAT_PERIODIC |
CLOCK_EVT_FEAT_ONESHOT;
fttmr010->clkevt.set_next_event = fttmr010_timer_set_next_event;
fttmr010->clkevt.set_state_shutdown = fttmr010_timer_shutdown;
fttmr010->clkevt.set_state_periodic = fttmr010_timer_set_periodic;
fttmr010->clkevt.set_state_oneshot = fttmr010_timer_set_oneshot;
fttmr010->clkevt.tick_resume = fttmr010_timer_shutdown;
fttmr010->clkevt.cpumask = cpumask_of(0);
fttmr010->clkevt.irq = irq;
clockevents_config_and_register(&fttmr010->clkevt,
fttmr010->tick_rate,
1, 0xffffffff);
return 0;
out_unmap:
iounmap(fttmr010->base);
out_free:
kfree(fttmr010);
out_disable_clock:
clk_disable_unprepare(clk);
return ret;
}
CLOCKSOURCE_OF_DECLARE(fttmr010, "faraday,fttmr010", fttmr010_timer_init);
CLOCKSOURCE_OF_DECLARE(gemini, "cortina,gemini-timer", fttmr010_timer_init);
