315 lines
8.1 KiB
C
315 lines
8.1 KiB
C
|
/*
|
||
|
|
* Clocksource driver for NXP LPC32xx/18xx/43xx timer
|
||
|
|
*
|
||
|
|
* Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com>
|
||
|
|
*
|
||
|
|
* Based on:
|
||
|
|
* time-efm32 Copyright (C) 2013 Pengutronix
|
||
|
|
* mach-lpc32xx/timer.c Copyright (C) 2009 - 2010 NXP Semiconductors
|
||
|
|
*
|
||
|
|
* 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.
|
||
|
|
*
|
||
|
|
*/
|
||
|
|
|
||
|
|
#define pr_fmt(fmt) "%s: " fmt, __func__
|
||
|
|
|
||
|
|
#include <linux/clk.h>
|
||
|
|
#include <linux/clockchips.h>
|
||
|
|
#include <linux/clocksource.h>
|
||
|
|
#include <linux/delay.h>
|
||
|
|
#include <linux/interrupt.h>
|
||
|
|
#include <linux/irq.h>
|
||
|
|
#include <linux/kernel.h>
|
||
|
|
#include <linux/of.h>
|
||
|
|
#include <linux/of_address.h>
|
||
|
|
#include <linux/of_irq.h>
|
||
|
|
#include <linux/sched_clock.h>
|
||
|
|
|
||
|
|
#define LPC32XX_TIMER_IR 0x000
|
||
|
|
#define LPC32XX_TIMER_IR_MR0INT BIT(0)
|
||
|
|
#define LPC32XX_TIMER_TCR 0x004
|
||
|
|
#define LPC32XX_TIMER_TCR_CEN BIT(0)
|
||
|
|
#define LPC32XX_TIMER_TCR_CRST BIT(1)
|
||
|
|
#define LPC32XX_TIMER_TC 0x008
|
||
|
|
#define LPC32XX_TIMER_PR 0x00c
|
||
|
|
#define LPC32XX_TIMER_MCR 0x014
|
||
|
|
#define LPC32XX_TIMER_MCR_MR0I BIT(0)
|
||
|
|
#define LPC32XX_TIMER_MCR_MR0R BIT(1)
|
||
|
|
#define LPC32XX_TIMER_MCR_MR0S BIT(2)
|
||
|
|
#define LPC32XX_TIMER_MR0 0x018
|
||
|
|
#define LPC32XX_TIMER_CTCR 0x070
|
||
|
|
|
||
|
|
struct lpc32xx_clock_event_ddata {
|
||
|
|
struct clock_event_device evtdev;
|
||
|
|
void __iomem *base;
|
||
|
|
u32 ticks_per_jiffy;
|
||
|
|
};
|
||
|
|
|
||
|
|
/* Needed for the sched clock */
|
||
|
|
static void __iomem *clocksource_timer_counter;
|
||
|
|
|
||
|
|
static u64 notrace lpc32xx_read_sched_clock(void)
|
||
|
|
{
|
||
|
|
return readl(clocksource_timer_counter);
|
||
|
|
}
|
||
|
|
|
||
|
|
static unsigned long lpc32xx_delay_timer_read(void)
|
||
|
|
{
|
||
|
|
return readl(clocksource_timer_counter);
|
||
|
|
}
|
||
|
|
|
||
|
|
static struct delay_timer lpc32xx_delay_timer = {
|
||
|
|
.read_current_timer = lpc32xx_delay_timer_read,
|
||
|
|
};
|
||
|
|
|
||
|
|
static int lpc32xx_clkevt_next_event(unsigned long delta,
|
||
|
|
struct clock_event_device *evtdev)
|
||
|
|
{
|
||
|
|
struct lpc32xx_clock_event_ddata *ddata =
|
||
|
|
container_of(evtdev, struct lpc32xx_clock_event_ddata, evtdev);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Place timer in reset and program the delta in the match
|
||
|
|
* channel 0 (MR0). When the timer counter matches the value
|
||
|
|
* in MR0 register the match will trigger an interrupt.
|
||
|
|
* After setup the timer is released from reset and enabled.
|
||
|
|
*/
|
||
|
|
writel_relaxed(LPC32XX_TIMER_TCR_CRST, ddata->base + LPC32XX_TIMER_TCR);
|
||
|
|
writel_relaxed(delta, ddata->base + LPC32XX_TIMER_MR0);
|
||
|
|
writel_relaxed(LPC32XX_TIMER_TCR_CEN, ddata->base + LPC32XX_TIMER_TCR);
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
static int lpc32xx_clkevt_shutdown(struct clock_event_device *evtdev)
|
||
|
|
{
|
||
|
|
struct lpc32xx_clock_event_ddata *ddata =
|
||
|
|
container_of(evtdev, struct lpc32xx_clock_event_ddata, evtdev);
|
||
|
|
|
||
|
|
/* Disable the timer */
|
||
|
|
writel_relaxed(0, ddata->base + LPC32XX_TIMER_TCR);
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
static int lpc32xx_clkevt_oneshot(struct clock_event_device *evtdev)
|
||
|
|
{
|
||
|
|
struct lpc32xx_clock_event_ddata *ddata =
|
||
|
|
container_of(evtdev, struct lpc32xx_clock_event_ddata, evtdev);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* When using oneshot, we must also disable the timer
|
||
|
|
* to wait for the first call to set_next_event().
|
||
|
|
*/
|
||
|
|
writel_relaxed(0, ddata->base + LPC32XX_TIMER_TCR);
|
||
|
|
|
||
|
|
/* Enable interrupt, reset on match and stop on match (MCR). */
|
||
|
|
writel_relaxed(LPC32XX_TIMER_MCR_MR0I | LPC32XX_TIMER_MCR_MR0R |
|
||
|
|
LPC32XX_TIMER_MCR_MR0S, ddata->base + LPC32XX_TIMER_MCR);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
static int lpc32xx_clkevt_periodic(struct clock_event_device *evtdev)
|
||
|
|
{
|
||
|
|
struct lpc32xx_clock_event_ddata *ddata =
|
||
|
|
container_of(evtdev, struct lpc32xx_clock_event_ddata, evtdev);
|
||
|
|
|
||
|
|
/* Enable interrupt and reset on match. */
|
||
|
|
writel_relaxed(LPC32XX_TIMER_MCR_MR0I | LPC32XX_TIMER_MCR_MR0R,
|
||
|
|
ddata->base + LPC32XX_TIMER_MCR);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Place timer in reset and program the delta in the match
|
||
|
|
* channel 0 (MR0).
|
||
|
|
*/
|
||
|
|
writel_relaxed(LPC32XX_TIMER_TCR_CRST, ddata->base + LPC32XX_TIMER_TCR);
|
||
|
|
writel_relaxed(ddata->ticks_per_jiffy, ddata->base + LPC32XX_TIMER_MR0);
|
||
|
|
writel_relaxed(LPC32XX_TIMER_TCR_CEN, ddata->base + LPC32XX_TIMER_TCR);
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
static irqreturn_t lpc32xx_clock_event_handler(int irq, void *dev_id)
|
||
|
|
{
|
||
|
|
struct lpc32xx_clock_event_ddata *ddata = dev_id;
|
||
|
|
|
||
|
|
/* Clear match on channel 0 */
|
||
|
|
writel_relaxed(LPC32XX_TIMER_IR_MR0INT, ddata->base + LPC32XX_TIMER_IR);
|
||
|
|
|
||
|
|
ddata->evtdev.event_handler(&ddata->evtdev);
|
||
|
|
|
||
|
|
return IRQ_HANDLED;
|
||
|
|
}
|
||
|
|
|
||
|
|
static struct lpc32xx_clock_event_ddata lpc32xx_clk_event_ddata = {
|
||
|
|
.evtdev = {
|
||
|
|
.name = "lpc3220 clockevent",
|
||
|
|
.features = CLOCK_EVT_FEAT_ONESHOT |
|
||
|
|
CLOCK_EVT_FEAT_PERIODIC,
|
||
|
|
.rating = 300,
|
||
|
|
.set_next_event = lpc32xx_clkevt_next_event,
|
||
|
|
.set_state_shutdown = lpc32xx_clkevt_shutdown,
|
||
|
|
.set_state_oneshot = lpc32xx_clkevt_oneshot,
|
||
|
|
.set_state_periodic = lpc32xx_clkevt_periodic,
|
||
|
|
},
|
||
|
|
};
|
||
|
|
|
||
|
|
static int __init lpc32xx_clocksource_init(struct device_node *np)
|
||
|
|
{
|
||
|
|
void __iomem *base;
|
||
|
|
unsigned long rate;
|
||
|
|
struct clk *clk;
|
||
|
|
int ret;
|
||
|
|
|
||
|
|
clk = of_clk_get_by_name(np, "timerclk");
|
||
|
|
if (IS_ERR(clk)) {
|
||
|
|
pr_err("clock get failed (%ld)\n", PTR_ERR(clk));
|
||
|
|
return PTR_ERR(clk);
|
||
|
|
}
|
||
|
|
|
||
|
|
ret = clk_prepare_enable(clk);
|
||
|
|
if (ret) {
|
||
|
|
pr_err("clock enable failed (%d)\n", ret);
|
||
|
|
goto err_clk_enable;
|
||
|
|
}
|
||
|
|
|
||
|
|
base = of_iomap(np, 0);
|
||
|
|
if (!base) {
|
||
|
|
pr_err("unable to map registers\n");
|
||
|
|
ret = -EADDRNOTAVAIL;
|
||
|
|
goto err_iomap;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Disable and reset timer then set it to free running timer
|
||
|
|
* mode (CTCR) with no prescaler (PR) or match operations (MCR).
|
||
|
|
* After setup the timer is released from reset and enabled.
|
||
|
|
*/
|
||
|
|
writel_relaxed(LPC32XX_TIMER_TCR_CRST, base + LPC32XX_TIMER_TCR);
|
||
|
|
writel_relaxed(0, base + LPC32XX_TIMER_PR);
|
||
|
|
writel_relaxed(0, base + LPC32XX_TIMER_MCR);
|
||
|
|
writel_relaxed(0, base + LPC32XX_TIMER_CTCR);
|
||
|
|
writel_relaxed(LPC32XX_TIMER_TCR_CEN, base + LPC32XX_TIMER_TCR);
|
||
|
|
|
||
|
|
rate = clk_get_rate(clk);
|
||
|
|
ret = clocksource_mmio_init(base + LPC32XX_TIMER_TC, "lpc3220 timer",
|
||
|
|
rate, 300, 32, clocksource_mmio_readl_up);
|
||
|
|
if (ret) {
|
||
|
|
pr_err("failed to init clocksource (%d)\n", ret);
|
||
|
|
goto err_clocksource_init;
|
||
|
|
}
|
||
|
|
|
||
|
|
clocksource_timer_counter = base + LPC32XX_TIMER_TC;
|
||
|
|
lpc32xx_delay_timer.freq = rate;
|
||
|
|
register_current_timer_delay(&lpc32xx_delay_timer);
|
||
|
|
sched_clock_register(lpc32xx_read_sched_clock, 32, rate);
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
err_clocksource_init:
|
||
|
|
iounmap(base);
|
||
|
|
err_iomap:
|
||
|
|
clk_disable_unprepare(clk);
|
||
|
|
err_clk_enable:
|
||
|
|
clk_put(clk);
|
||
|
|
return ret;
|
||
|
|
}
|
||
|
|
|
||
|
|
static int __init lpc32xx_clockevent_init(struct device_node *np)
|
||
|
|
{
|
||
|
|
void __iomem *base;
|
||
|
|
unsigned long rate;
|
||
|
|
struct clk *clk;
|
||
|
|
int ret, irq;
|
||
|
|
|
||
|
|
clk = of_clk_get_by_name(np, "timerclk");
|
||
|
|
if (IS_ERR(clk)) {
|
||
|
|
pr_err("clock get failed (%ld)\n", PTR_ERR(clk));
|
||
|
|
return PTR_ERR(clk);
|
||
|
|
}
|
||
|
|
|
||
|
|
ret = clk_prepare_enable(clk);
|
||
|
|
if (ret) {
|
||
|
|
pr_err("clock enable failed (%d)\n", ret);
|
||
|
|
goto err_clk_enable;
|
||
|
|
}
|
||
|
|
|
||
|
|
base = of_iomap(np, 0);
|
||
|
|
if (!base) {
|
||
|
|
pr_err("unable to map registers\n");
|
||
|
|
ret = -EADDRNOTAVAIL;
|
||
|
|
goto err_iomap;
|
||
|
|
}
|
||
|
|
|
||
|
|
irq = irq_of_parse_and_map(np, 0);
|
||
|
|
if (!irq) {
|
||
|
|
pr_err("get irq failed\n");
|
||
|
|
ret = -ENOENT;
|
||
|
|
goto err_irq;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Disable timer and clear any pending interrupt (IR) on match
|
||
|
|
* channel 0 (MR0). Clear the prescaler as it's not used.
|
||
|
|
*/
|
||
|
|
writel_relaxed(0, base + LPC32XX_TIMER_TCR);
|
||
|
|
writel_relaxed(0, base + LPC32XX_TIMER_PR);
|
||
|
|
writel_relaxed(0, base + LPC32XX_TIMER_CTCR);
|
||
|
|
writel_relaxed(LPC32XX_TIMER_IR_MR0INT, base + LPC32XX_TIMER_IR);
|
||
|
|
|
||
|
|
rate = clk_get_rate(clk);
|
||
|
|
lpc32xx_clk_event_ddata.base = base;
|
||
|
|
lpc32xx_clk_event_ddata.ticks_per_jiffy = DIV_ROUND_CLOSEST(rate, HZ);
|
||
|
|
clockevents_config_and_register(&lpc32xx_clk_event_ddata.evtdev,
|
||
|
|
rate, 1, -1);
|
||
|
|
|
||
|
|
ret = request_irq(irq, lpc32xx_clock_event_handler,
|
||
|
|
IRQF_TIMER | IRQF_IRQPOLL, "lpc3220 clockevent",
|
||
|
|
&lpc32xx_clk_event_ddata);
|
||
|
|
if (ret) {
|
||
|
|
pr_err("request irq failed\n");
|
||
|
|
goto err_irq;
|
||
|
|
}
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
err_irq:
|
||
|
|
iounmap(base);
|
||
|
|
err_iomap:
|
||
|
|
clk_disable_unprepare(clk);
|
||
|
|
err_clk_enable:
|
||
|
|
clk_put(clk);
|
||
|
|
return ret;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* This function asserts that we have exactly one clocksource and one
|
||
|
|
* clock_event_device in the end.
|
||
|
|
*/
|
||
|
|
static int __init lpc32xx_timer_init(struct device_node *np)
|
||
|
|
{
|
||
|
|
static int has_clocksource, has_clockevent;
|
||
|
|
int ret = 0;
|
||
|
|
|
||
|
|
if (!has_clocksource) {
|
||
|
|
ret = lpc32xx_clocksource_init(np);
|
||
|
|
if (!ret) {
|
||
|
|
has_clocksource = 1;
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
if (!has_clockevent) {
|
||
|
|
ret = lpc32xx_clockevent_init(np);
|
||
|
|
if (!ret) {
|
||
|
|
has_clockevent = 1;
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
return ret;
|
||
|
|
}
|
||
|
|
CLOCKSOURCE_OF_DECLARE(lpc32xx_timer, "nxp,lpc3220-timer", lpc32xx_timer_init);
|