drivers/clocksource/timer-goldfish.c

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

File Facts

System
Linux kernel
Corpus path
drivers/clocksource/timer-goldfish.c
Extension
.c
Size
3643 bytes
Lines
154
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

struct goldfish_timer {
	struct clocksource cs;
	struct clock_event_device ced;
	struct resource res;
	void __iomem *base;
};

static struct goldfish_timer *ced_to_gf(struct clock_event_device *ced)
{
	return container_of(ced, struct goldfish_timer, ced);
}

static struct goldfish_timer *cs_to_gf(struct clocksource *cs)
{
	return container_of(cs, struct goldfish_timer, cs);
}

static u64 goldfish_timer_read(struct clocksource *cs)
{
	struct goldfish_timer *timerdrv = cs_to_gf(cs);
	void __iomem *base = timerdrv->base;
	u32 time_low, time_high;
	u64 ticks;

	/*
	 * time_low: get low bits of current time and update time_high
	 * time_high: get high bits of time at last time_low read
	 */
	time_low = gf_ioread32(base + TIMER_TIME_LOW);
	time_high = gf_ioread32(base + TIMER_TIME_HIGH);

	ticks = ((u64)time_high << 32) | time_low;

	return ticks;
}

static int goldfish_timer_set_oneshot(struct clock_event_device *evt)
{
	struct goldfish_timer *timerdrv = ced_to_gf(evt);
	void __iomem *base = timerdrv->base;

	gf_iowrite32(0, base + TIMER_ALARM_HIGH);
	gf_iowrite32(0, base + TIMER_ALARM_LOW);
	gf_iowrite32(1, base + TIMER_IRQ_ENABLED);

	return 0;
}

static int goldfish_timer_shutdown(struct clock_event_device *evt)
{
	struct goldfish_timer *timerdrv = ced_to_gf(evt);
	void __iomem *base = timerdrv->base;

	gf_iowrite32(0, base + TIMER_IRQ_ENABLED);

	return 0;
}

static int goldfish_timer_next_event(unsigned long delta,
				     struct clock_event_device *evt)
{
	struct goldfish_timer *timerdrv = ced_to_gf(evt);
	void __iomem *base = timerdrv->base;
	u64 now;

	now = goldfish_timer_read(&timerdrv->cs);

	now += delta;

	gf_iowrite32(upper_32_bits(now), base + TIMER_ALARM_HIGH);
	gf_iowrite32(lower_32_bits(now), base + TIMER_ALARM_LOW);

	return 0;
}

static irqreturn_t goldfish_timer_irq(int irq, void *dev_id)
{
	struct goldfish_timer *timerdrv = dev_id;
	struct clock_event_device *evt = &timerdrv->ced;
	void __iomem *base = timerdrv->base;

	gf_iowrite32(1, base + TIMER_CLEAR_INTERRUPT);

	evt->event_handler(evt);

	return IRQ_HANDLED;
}

int __init goldfish_timer_init(int irq, void __iomem *base)
{

Annotation

Implementation Notes