linux/drivers/clocksource/pxa_timer.c
Daniel Lezcano 1727339590 clocksource/drivers: Rename CLOCKSOURCE_OF_DECLARE to TIMER_OF_DECLARE
The CLOCKSOURCE_OF_DECLARE macro is used widely for the timers to declare the
clocksource at early stage. However, this macro is also used to initialize
the clockevent if any, or the clockevent only.

It was originally suggested to declare another macro to initialize a
clockevent, so in order to separate the two entities even they belong to the
same IP. This was not accepted because of the impact on the DT where splitting
a clocksource/clockevent definition does not make sense as it is a Linux
concept not a hardware description.

On the other side, the clocksource has not interrupt declared while the
clockevent has, so it is easy from the driver to know if the description is
for a clockevent or a clocksource, IOW it could be implemented at the driver
level.

So instead of dealing with a named clocksource macro, let's use a more generic
one: TIMER_OF_DECLARE.

The patch has not functional changes.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Matthias Brugger <matthias.bgg@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
2017-06-14 11:58:45 +02:00

237 lines
6.1 KiB
C

/*
* arch/arm/mach-pxa/time.c
*
* PXA clocksource, clockevents, and OST interrupt handlers.
* Copyright (c) 2007 by Bill Gatliff <bgat@billgatliff.com>.
*
* Derived from Nicolas Pitre's PXA timer handler Copyright (c) 2001
* by MontaVista Software, Inc. (Nico, your code rocks!)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/clk.h>
#include <linux/clockchips.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/sched/clock.h>
#include <linux/sched_clock.h>
#include <clocksource/pxa.h>
#include <asm/div64.h>
#define OSMR0 0x00 /* OS Timer 0 Match Register */
#define OSMR1 0x04 /* OS Timer 1 Match Register */
#define OSMR2 0x08 /* OS Timer 2 Match Register */
#define OSMR3 0x0C /* OS Timer 3 Match Register */
#define OSCR 0x10 /* OS Timer Counter Register */
#define OSSR 0x14 /* OS Timer Status Register */
#define OWER 0x18 /* OS Timer Watchdog Enable Register */
#define OIER 0x1C /* OS Timer Interrupt Enable Register */
#define OSSR_M3 (1 << 3) /* Match status channel 3 */
#define OSSR_M2 (1 << 2) /* Match status channel 2 */
#define OSSR_M1 (1 << 1) /* Match status channel 1 */
#define OSSR_M0 (1 << 0) /* Match status channel 0 */
#define OIER_E0 (1 << 0) /* Interrupt enable channel 0 */
/*
* This is PXA's sched_clock implementation. This has a resolution
* of at least 308 ns and a maximum value of 208 days.
*
* The return value is guaranteed to be monotonic in that range as
* long as there is always less than 582 seconds between successive
* calls to sched_clock() which should always be the case in practice.
*/
#define timer_readl(reg) readl_relaxed(timer_base + (reg))
#define timer_writel(val, reg) writel_relaxed((val), timer_base + (reg))
static void __iomem *timer_base;
static u64 notrace pxa_read_sched_clock(void)
{
return timer_readl(OSCR);
}
#define MIN_OSCR_DELTA 16
static irqreturn_t
pxa_ost0_interrupt(int irq, void *dev_id)
{
struct clock_event_device *c = dev_id;
/* Disarm the compare/match, signal the event. */
timer_writel(timer_readl(OIER) & ~OIER_E0, OIER);
timer_writel(OSSR_M0, OSSR);
c->event_handler(c);
return IRQ_HANDLED;
}
static int
pxa_osmr0_set_next_event(unsigned long delta, struct clock_event_device *dev)
{
unsigned long next, oscr;
timer_writel(timer_readl(OIER) | OIER_E0, OIER);
next = timer_readl(OSCR) + delta;
timer_writel(next, OSMR0);
oscr = timer_readl(OSCR);
return (signed)(next - oscr) <= MIN_OSCR_DELTA ? -ETIME : 0;
}
static int pxa_osmr0_shutdown(struct clock_event_device *evt)
{
/* initializing, released, or preparing for suspend */
timer_writel(timer_readl(OIER) & ~OIER_E0, OIER);
timer_writel(OSSR_M0, OSSR);
return 0;
}
#ifdef CONFIG_PM
static unsigned long osmr[4], oier, oscr;
static void pxa_timer_suspend(struct clock_event_device *cedev)
{
osmr[0] = timer_readl(OSMR0);
osmr[1] = timer_readl(OSMR1);
osmr[2] = timer_readl(OSMR2);
osmr[3] = timer_readl(OSMR3);
oier = timer_readl(OIER);
oscr = timer_readl(OSCR);
}
static void pxa_timer_resume(struct clock_event_device *cedev)
{
/*
* Ensure that we have at least MIN_OSCR_DELTA between match
* register 0 and the OSCR, to guarantee that we will receive
* the one-shot timer interrupt. We adjust OSMR0 in preference
* to OSCR to guarantee that OSCR is monotonically incrementing.
*/
if (osmr[0] - oscr < MIN_OSCR_DELTA)
osmr[0] += MIN_OSCR_DELTA;
timer_writel(osmr[0], OSMR0);
timer_writel(osmr[1], OSMR1);
timer_writel(osmr[2], OSMR2);
timer_writel(osmr[3], OSMR3);
timer_writel(oier, OIER);
timer_writel(oscr, OSCR);
}
#else
#define pxa_timer_suspend NULL
#define pxa_timer_resume NULL
#endif
static struct clock_event_device ckevt_pxa_osmr0 = {
.name = "osmr0",
.features = CLOCK_EVT_FEAT_ONESHOT,
.rating = 200,
.set_next_event = pxa_osmr0_set_next_event,
.set_state_shutdown = pxa_osmr0_shutdown,
.set_state_oneshot = pxa_osmr0_shutdown,
.suspend = pxa_timer_suspend,
.resume = pxa_timer_resume,
};
static struct irqaction pxa_ost0_irq = {
.name = "ost0",
.flags = IRQF_TIMER | IRQF_IRQPOLL,
.handler = pxa_ost0_interrupt,
.dev_id = &ckevt_pxa_osmr0,
};
static int __init pxa_timer_common_init(int irq, unsigned long clock_tick_rate)
{
int ret;
timer_writel(0, OIER);
timer_writel(OSSR_M0 | OSSR_M1 | OSSR_M2 | OSSR_M3, OSSR);
sched_clock_register(pxa_read_sched_clock, 32, clock_tick_rate);
ckevt_pxa_osmr0.cpumask = cpumask_of(0);
ret = setup_irq(irq, &pxa_ost0_irq);
if (ret) {
pr_err("Failed to setup irq\n");
return ret;
}
ret = clocksource_mmio_init(timer_base + OSCR, "oscr0", clock_tick_rate, 200,
32, clocksource_mmio_readl_up);
if (ret) {
pr_err("Failed to init clocksource\n");
return ret;
}
clockevents_config_and_register(&ckevt_pxa_osmr0, clock_tick_rate,
MIN_OSCR_DELTA * 2, 0x7fffffff);
return 0;
}
static int __init pxa_timer_dt_init(struct device_node *np)
{
struct clk *clk;
int irq, ret;
/* timer registers are shared with watchdog timer */
timer_base = of_iomap(np, 0);
if (!timer_base) {
pr_err("%s: unable to map resource\n", np->name);
return -ENXIO;
}
clk = of_clk_get(np, 0);
if (IS_ERR(clk)) {
pr_crit("%s: unable to get clk\n", np->name);
return PTR_ERR(clk);
}
ret = clk_prepare_enable(clk);
if (ret) {
pr_crit("Failed to prepare clock\n");
return ret;
}
/* we are only interested in OS-timer0 irq */
irq = irq_of_parse_and_map(np, 0);
if (irq <= 0) {
pr_crit("%s: unable to parse OS-timer0 irq\n", np->name);
return -EINVAL;
}
return pxa_timer_common_init(irq, clk_get_rate(clk));
}
TIMER_OF_DECLARE(pxa_timer, "marvell,pxa-timer", pxa_timer_dt_init);
/*
* Legacy timer init for non device-tree boards.
*/
void __init pxa_timer_nodt_init(int irq, void __iomem *base)
{
struct clk *clk;
timer_base = base;
clk = clk_get(NULL, "OSTIMER0");
if (clk && !IS_ERR(clk)) {
clk_prepare_enable(clk);
pxa_timer_common_init(irq, clk_get_rate(clk));
} else {
pr_crit("%s: unable to get clk\n", __func__);
}
}