mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 09:19:51 +00:00
![afzal mohammed](/assets/img/avatar_default.png)
request_irq() is preferred over setup_irq(). The early boot setup_irq() invocations happen either via 'init_IRQ()' or 'time_init()', while memory allocators are ready by 'mm_init()'. Per tglx[1], setup_irq() existed in olden days when allocators were not ready by the time early interrupts were initialized. Hence replace setup_irq() by request_irq(). Seldom remove_irq() usage has been observed coupled with setup_irq(), wherever that has been found, it too has been replaced by free_irq(). A build error that was reported by kbuild test robot <lkp@intel.com> in the previous version of the patch also has been fixed. [1] https://lkml.kernel.org/r/alpine.DEB.2.20.1710191609480.1971@nanos Signed-off-by: afzal mohammed <afzal.mohd.ma@gmail.com> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Link: https://lore.kernel.org/r/91961c77c1cf93d41523f5e1ac52043f32f97077.1582799709.git.afzal.mohd.ma@gmail.com
150 lines
3.9 KiB
C
150 lines
3.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/*
|
|
* arch/arm/mach-vt8500/timer.c
|
|
*
|
|
* Copyright (C) 2012 Tony Prisk <linux@prisktech.co.nz>
|
|
* Copyright (C) 2010 Alexey Charkov <alchark@gmail.com>
|
|
*/
|
|
|
|
/*
|
|
* This file is copied and modified from the original timer.c provided by
|
|
* Alexey Charkov. Minor changes have been made for Device Tree Support.
|
|
*/
|
|
|
|
#include <linux/io.h>
|
|
#include <linux/irq.h>
|
|
#include <linux/interrupt.h>
|
|
#include <linux/clocksource.h>
|
|
#include <linux/clockchips.h>
|
|
#include <linux/delay.h>
|
|
|
|
#include <linux/of.h>
|
|
#include <linux/of_address.h>
|
|
#include <linux/of_irq.h>
|
|
|
|
#define VT8500_TIMER_OFFSET 0x0100
|
|
#define VT8500_TIMER_HZ 3000000
|
|
#define TIMER_MATCH_VAL 0x0000
|
|
#define TIMER_COUNT_VAL 0x0010
|
|
#define TIMER_STATUS_VAL 0x0014
|
|
#define TIMER_IER_VAL 0x001c /* interrupt enable */
|
|
#define TIMER_CTRL_VAL 0x0020
|
|
#define TIMER_AS_VAL 0x0024 /* access status */
|
|
#define TIMER_COUNT_R_ACTIVE (1 << 5) /* not ready for read */
|
|
#define TIMER_COUNT_W_ACTIVE (1 << 4) /* not ready for write */
|
|
#define TIMER_MATCH_W_ACTIVE (1 << 0) /* not ready for write */
|
|
|
|
#define msecs_to_loops(t) (loops_per_jiffy / 1000 * HZ * t)
|
|
|
|
#define MIN_OSCR_DELTA 16
|
|
|
|
static void __iomem *regbase;
|
|
|
|
static u64 vt8500_timer_read(struct clocksource *cs)
|
|
{
|
|
int loops = msecs_to_loops(10);
|
|
writel(3, regbase + TIMER_CTRL_VAL);
|
|
while ((readl((regbase + TIMER_AS_VAL)) & TIMER_COUNT_R_ACTIVE)
|
|
&& --loops)
|
|
cpu_relax();
|
|
return readl(regbase + TIMER_COUNT_VAL);
|
|
}
|
|
|
|
static struct clocksource clocksource = {
|
|
.name = "vt8500_timer",
|
|
.rating = 200,
|
|
.read = vt8500_timer_read,
|
|
.mask = CLOCKSOURCE_MASK(32),
|
|
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
|
|
};
|
|
|
|
static int vt8500_timer_set_next_event(unsigned long cycles,
|
|
struct clock_event_device *evt)
|
|
{
|
|
int loops = msecs_to_loops(10);
|
|
u64 alarm = clocksource.read(&clocksource) + cycles;
|
|
while ((readl(regbase + TIMER_AS_VAL) & TIMER_MATCH_W_ACTIVE)
|
|
&& --loops)
|
|
cpu_relax();
|
|
writel((unsigned long)alarm, regbase + TIMER_MATCH_VAL);
|
|
|
|
if ((signed)(alarm - clocksource.read(&clocksource)) <= MIN_OSCR_DELTA)
|
|
return -ETIME;
|
|
|
|
writel(1, regbase + TIMER_IER_VAL);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int vt8500_shutdown(struct clock_event_device *evt)
|
|
{
|
|
writel(readl(regbase + TIMER_CTRL_VAL) | 1, regbase + TIMER_CTRL_VAL);
|
|
writel(0, regbase + TIMER_IER_VAL);
|
|
return 0;
|
|
}
|
|
|
|
static struct clock_event_device clockevent = {
|
|
.name = "vt8500_timer",
|
|
.features = CLOCK_EVT_FEAT_ONESHOT,
|
|
.rating = 200,
|
|
.set_next_event = vt8500_timer_set_next_event,
|
|
.set_state_shutdown = vt8500_shutdown,
|
|
.set_state_oneshot = vt8500_shutdown,
|
|
};
|
|
|
|
static irqreturn_t vt8500_timer_interrupt(int irq, void *dev_id)
|
|
{
|
|
struct clock_event_device *evt = dev_id;
|
|
writel(0xf, regbase + TIMER_STATUS_VAL);
|
|
evt->event_handler(evt);
|
|
|
|
return IRQ_HANDLED;
|
|
}
|
|
|
|
static int __init vt8500_timer_init(struct device_node *np)
|
|
{
|
|
int timer_irq, ret;
|
|
|
|
regbase = of_iomap(np, 0);
|
|
if (!regbase) {
|
|
pr_err("%s: Missing iobase description in Device Tree\n",
|
|
__func__);
|
|
return -ENXIO;
|
|
}
|
|
|
|
timer_irq = irq_of_parse_and_map(np, 0);
|
|
if (!timer_irq) {
|
|
pr_err("%s: Missing irq description in Device Tree\n",
|
|
__func__);
|
|
return -EINVAL;
|
|
}
|
|
|
|
writel(1, regbase + TIMER_CTRL_VAL);
|
|
writel(0xf, regbase + TIMER_STATUS_VAL);
|
|
writel(~0, regbase + TIMER_MATCH_VAL);
|
|
|
|
ret = clocksource_register_hz(&clocksource, VT8500_TIMER_HZ);
|
|
if (ret) {
|
|
pr_err("%s: clocksource_register failed for %s\n",
|
|
__func__, clocksource.name);
|
|
return ret;
|
|
}
|
|
|
|
clockevent.cpumask = cpumask_of(0);
|
|
|
|
ret = request_irq(timer_irq, vt8500_timer_interrupt,
|
|
IRQF_TIMER | IRQF_IRQPOLL, "vt8500_timer",
|
|
&clockevent);
|
|
if (ret) {
|
|
pr_err("%s: setup_irq failed for %s\n", __func__,
|
|
clockevent.name);
|
|
return ret;
|
|
}
|
|
|
|
clockevents_config_and_register(&clockevent, VT8500_TIMER_HZ,
|
|
MIN_OSCR_DELTA * 2, 0xf0000000);
|
|
|
|
return 0;
|
|
}
|
|
|
|
TIMER_OF_DECLARE(vt8500, "via,vt8500-timer", vt8500_timer_init);
|