drivers/clocksource/timer-gx6605s.c

Source file repositories/reference/linux-study-clean/drivers/clocksource/timer-gx6605s.c

File Facts

System
Linux kernel
Corpus path
drivers/clocksource/timer-gx6605s.c
Extension
.c
Size
4091 bytes
Lines
156
Domain
Driver Families
Bucket
drivers/clocksource
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.

#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/sched_clock.h>

#include "timer-of.h"

#define CLKSRC_OFFSET	0x40

#define TIMER_STATUS	0x00
#define TIMER_VALUE	0x04
#define TIMER_CONTRL	0x10
#define TIMER_CONFIG	0x20
#define TIMER_DIV	0x24
#define TIMER_INI	0x28

#define GX6605S_STATUS_CLR	BIT(0)
#define GX6605S_CONTRL_RST	BIT(0)
#define GX6605S_CONTRL_START	BIT(1)
#define GX6605S_CONFIG_EN	BIT(0)
#define GX6605S_CONFIG_IRQ_EN	BIT(1)

static irqreturn_t gx6605s_timer_interrupt(int irq, void *dev)
{
	struct clock_event_device *ce = dev;
	void __iomem *base = timer_of_base(to_timer_of(ce));

	writel_relaxed(GX6605S_STATUS_CLR, base + TIMER_STATUS);
	writel_relaxed(0, base + TIMER_INI);

	ce->event_handler(ce);

	return IRQ_HANDLED;
}

static int gx6605s_timer_set_oneshot(struct clock_event_device *ce)
{
	void __iomem *base = timer_of_base(to_timer_of(ce));

	/* reset and stop counter */
	writel_relaxed(GX6605S_CONTRL_RST, base + TIMER_CONTRL);

	/* enable with irq and start */
	writel_relaxed(GX6605S_CONFIG_EN | GX6605S_CONFIG_IRQ_EN,
		       base + TIMER_CONFIG);

	return 0;
}

static int gx6605s_timer_set_next_event(unsigned long delta,
					struct clock_event_device *ce)
{
	void __iomem *base = timer_of_base(to_timer_of(ce));

	/* use reset to pause timer */
	writel_relaxed(GX6605S_CONTRL_RST, base + TIMER_CONTRL);

	/* config next timeout value */
	writel_relaxed(ULONG_MAX - delta, base + TIMER_INI);
	writel_relaxed(GX6605S_CONTRL_START, base + TIMER_CONTRL);

	return 0;
}

static int gx6605s_timer_shutdown(struct clock_event_device *ce)
{
	void __iomem *base = timer_of_base(to_timer_of(ce));

	writel_relaxed(0, base + TIMER_CONTRL);
	writel_relaxed(0, base + TIMER_CONFIG);

	return 0;
}

static struct timer_of to = {
	.flags = TIMER_OF_IRQ | TIMER_OF_BASE | TIMER_OF_CLOCK,
	.clkevt = {
		.rating			= 300,
		.features		= CLOCK_EVT_FEAT_DYNIRQ |
					  CLOCK_EVT_FEAT_ONESHOT,
		.set_state_shutdown	= gx6605s_timer_shutdown,
		.set_state_oneshot	= gx6605s_timer_set_oneshot,
		.set_next_event		= gx6605s_timer_set_next_event,
		.cpumask		= cpu_possible_mask,
	},
	.of_irq = {
		.handler		= gx6605s_timer_interrupt,
		.flags			= IRQF_TIMER | IRQF_IRQPOLL,

Annotation

Implementation Notes