static __init int ixp4xx_timer_register()

in timer-ixp4xx.c [164:230]

• 46 lines of code
• 3 McCabe index (conditional complexity)

static __init int ixp4xx_timer_register(void __iomem *base,
					int timer_irq,
					unsigned int timer_freq)
{
	struct ixp4xx_timer *tmr;
	int ret;

	tmr = kzalloc(sizeof(*tmr), GFP_KERNEL);
	if (!tmr)
		return -ENOMEM;
	tmr->base = base;

	/*
	 * The timer register doesn't allow to specify the two least
	 * significant bits of the timeout value and assumes them being zero.
	 * So make sure the latch is the best value with the two least
	 * significant bits unset.
	 */
	tmr->latch = DIV_ROUND_CLOSEST(timer_freq,
				       (IXP4XX_OST_RELOAD_MASK + 1) * HZ)
		* (IXP4XX_OST_RELOAD_MASK + 1);

	local_ixp4xx_timer = tmr;

	/* Reset/disable counter */
	__raw_writel(0, tmr->base + IXP4XX_OSRT1_OFFSET);

	/* Clear any pending interrupt on timer 1 */
	__raw_writel(IXP4XX_OSST_TIMER_1_PEND,
		     tmr->base + IXP4XX_OSST_OFFSET);

	/* Reset time-stamp counter */
	__raw_writel(0, tmr->base + IXP4XX_OSTS_OFFSET);

	clocksource_mmio_init(NULL, "OSTS", timer_freq, 200, 32,
			      ixp4xx_clocksource_read);

	tmr->clkevt.name = "ixp4xx timer1";
	tmr->clkevt.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
	tmr->clkevt.rating = 200;
	tmr->clkevt.set_state_shutdown = ixp4xx_shutdown;
	tmr->clkevt.set_state_periodic = ixp4xx_set_periodic;
	tmr->clkevt.set_state_oneshot = ixp4xx_set_oneshot;
	tmr->clkevt.tick_resume = ixp4xx_resume;
	tmr->clkevt.set_next_event = ixp4xx_set_next_event;
	tmr->clkevt.cpumask = cpumask_of(0);
	tmr->clkevt.irq = timer_irq;
	ret = request_irq(timer_irq, ixp4xx_timer_interrupt,
			  IRQF_TIMER, "IXP4XX-TIMER1", tmr);
	if (ret) {
		pr_crit("no timer IRQ\n");
		return -ENODEV;
	}
	clockevents_config_and_register(&tmr->clkevt, timer_freq,
					0xf, 0xfffffffe);

	sched_clock_register(ixp4xx_read_sched_clock, 32, timer_freq);

#ifdef CONFIG_ARM
	/* Also use this timer for delays */
	tmr->delay_timer.read_current_timer = ixp4xx_read_timer;
	tmr->delay_timer.freq = timer_freq;
	register_current_timer_delay(&tmr->delay_timer);
#endif

	return 0;
}