arch/mips/ralink/timer.c

Source file repositories/reference/linux-study-clean/arch/mips/ralink/timer.c

File Facts

System
Linux kernel
Corpus path
arch/mips/ralink/timer.c
Extension
.c
Size
3477 bytes
Lines
156
Domain
Architecture Layer
Bucket
arch/mips
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

struct rt_timer {
	struct device	*dev;
	void __iomem	*membase;
	int		irq;
	unsigned long	timer_freq;
	unsigned long	timer_div;
};

static inline void rt_timer_w32(struct rt_timer *rt, u8 reg, u32 val)
{
	__raw_writel(val, rt->membase + reg);
}

static inline u32 rt_timer_r32(struct rt_timer *rt, u8 reg)
{
	return __raw_readl(rt->membase + reg);
}

static irqreturn_t rt_timer_irq(int irq, void *_rt)
{
	struct rt_timer *rt =  (struct rt_timer *) _rt;

	rt_timer_w32(rt, TIMER_REG_TMR0LOAD, rt->timer_freq / rt->timer_div);
	rt_timer_w32(rt, TIMER_REG_TMRSTAT, TMRSTAT_TMR0INT);

	return IRQ_HANDLED;
}


static int rt_timer_request(struct rt_timer *rt)
{
	int err = request_irq(rt->irq, rt_timer_irq, 0,
						dev_name(rt->dev), rt);
	if (err) {
		dev_err(rt->dev, "failed to request irq\n");
	} else {
		u32 t = TMR0CTL_MODE_PERIODIC | TMR0CTL_PRESCALE_VAL;
		rt_timer_w32(rt, TIMER_REG_TMR0CTL, t);
	}
	return err;
}

static int rt_timer_config(struct rt_timer *rt, unsigned long divisor)
{
	if (rt->timer_freq < divisor)
		rt->timer_div = rt->timer_freq;
	else
		rt->timer_div = divisor;

	rt_timer_w32(rt, TIMER_REG_TMR0LOAD, rt->timer_freq / rt->timer_div);

	return 0;
}

static int rt_timer_enable(struct rt_timer *rt)
{
	u32 t;

	rt_timer_w32(rt, TIMER_REG_TMR0LOAD, rt->timer_freq / rt->timer_div);

	t = rt_timer_r32(rt, TIMER_REG_TMR0CTL);
	t |= TMR0CTL_ENABLE;
	rt_timer_w32(rt, TIMER_REG_TMR0CTL, t);

	return 0;
}

static int rt_timer_probe(struct platform_device *pdev)
{
	struct rt_timer *rt;
	struct clk *clk;

	rt = devm_kzalloc(&pdev->dev, sizeof(*rt), GFP_KERNEL);
	if (!rt) {
		dev_err(&pdev->dev, "failed to allocate memory\n");
		return -ENOMEM;
	}

	rt->irq = platform_get_irq(pdev, 0);
	if (rt->irq < 0)
		return rt->irq;

	rt->membase = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
	if (IS_ERR(rt->membase))
		return PTR_ERR(rt->membase);

	clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(clk)) {
		dev_err(&pdev->dev, "failed get clock rate\n");
		return PTR_ERR(clk);

Annotation

Implementation Notes