On 11/25/2015 11:33 AM, Vladimir Murzin wrote:

bool "Clocksource for MPS2 SoCs" if COMPILE_TEST
depends on OF && ARM

extra line.

+static inline struct clockevent_mps2 *to_mps2_clkevt(struct clock_event_device *c)
+{
+	return container_of(c, struct clockevent_mps2, clkevt);
+}
+
+static void clockevent_mps2_writel(u32 val, struct clock_event_device *c, u32 offset)
+{
+	writel(val, to_mps2_clkevt(c)->reg + offset);
+}
+
+static int mps2_timer_shutdown(struct clock_event_device *ce)
+{
+	clockevent_mps2_writel(0, ce, TIMER_RELOAD);
+	clockevent_mps2_writel(0, ce, TIMER_CTRL);
+
+	return 0;
+}
+
+static int mps2_timer_set_next_event(unsigned long next, struct clock_event_device *ce)
+{
+	clockevent_mps2_writel(next, ce, TIMER_VALUE);
+	clockevent_mps2_writel(TIMER_CTRL_IE | TIMER_CTRL_ENABLE, ce, TIMER_CTRL);
+
+	return 0;
+}
+
+static int mps2_timer_set_periodic(struct clock_event_device *ce)
+{
+	u32 clock_count_per_tick = to_mps2_clkevt(ce)->clock_count_per_tick;
+
+	clockevent_mps2_writel(clock_count_per_tick, ce, TIMER_RELOAD);
+	clockevent_mps2_writel(clock_count_per_tick, ce, TIMER_VALUE);
+	clockevent_mps2_writel(TIMER_CTRL_IE | TIMER_CTRL_ENABLE, ce, TIMER_CTRL);
+
+	return 0;
+}
+
+static irqreturn_t mps2_timer_interrupt(int irq, void *dev_id)
+{
+	struct clockevent_mps2 *ce = dev_id;
+	u32 status = readl(ce->reg + TIMER_INT);
+
+	if (!status)
+		return IRQ_NONE;

Why that could happen ? Add a comment.

+
+	writel(1, ce->reg + TIMER_INT);
+
+	ce->clkevt.event_handler(&ce->clkevt);
+
+	return IRQ_HANDLED;
+}
+
+static int __init mps2_clockevents_init(struct device_node *np)
+{
+	void __iomem *base;
+	struct clk *clk;
+	struct irqaction *ia;
+	struct clockevent_mps2 *ce;
+	u32 rate;
+	int irq, ret;
+	const char *name = "mps2-clkevt";
+
+	ret = of_property_read_u32(np, "clock-frequency", &rate);
+

extra line.

+	if (ret) {
+		clk = of_clk_get(np, 0);
+		if (IS_ERR(clk)) {
+			ret = PTR_ERR(clk);
+			pr_err("failed to get clock for clockevent: %d\n", ret);
+			goto err_clk_get;
+		}
+
+		ret = clk_prepare_enable(clk);
+		if (ret) {
+			pr_err("failed to enable clock for clockevent: %d\n", ret);
+			clk_put(clk);
+			goto err_clk_enable;
+		}
+
+		rate = clk_get_rate(clk);
+	}
+
+	base = of_iomap(np, 0);
+	if (!base) {
+		ret = -EADDRNOTAVAIL;
+		pr_err("failed to map register for clockevent: %d\n", ret);
+		goto err_iomap;
+	}
+
+	irq = irq_of_parse_and_map(np, 0);
+	if (!irq) {
+		ret = -ENOENT;
+		pr_err("failed to get irq for clockevent: %d\n", ret);
+		goto err_get_irq;
+	}
+
+	ce = kzalloc(sizeof(struct clockevent_mps2), GFP_KERNEL);
+	if (!ce) {
+		ret = -ENOMEM;
+		pr_err("failed to allocate clockevent: %d\n", ret);
+		goto err_ce_alloc;
+	}
+
+	ce->reg = base;
+	ce->clock_count_per_tick = DIV_ROUND_CLOSEST(rate, HZ);
+	ce->clkevt.irq = irq;
+	ce->clkevt.name = name;
+	ce->clkevt.rating = 200;
+	ce->clkevt.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
+	ce->clkevt.cpumask = cpu_possible_mask;
+	ce->clkevt.set_state_shutdown	= mps2_timer_shutdown,
+	ce->clkevt.set_state_periodic	= mps2_timer_set_periodic,
+	ce->clkevt.set_state_oneshot	= mps2_timer_shutdown,
+	ce->clkevt.set_next_event	= mps2_timer_set_next_event;
+
+	ia = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
+	if (!ia) {
+		ret = -ENOMEM;
+		pr_err("failed to allocate irqaction: %d\n", ret);
+		goto err_ia_alloc;
+	}
+
+	ia->name = name;
+	ia->flags = IRQF_TIMER;
+	ia->handler = mps2_timer_interrupt;
+	ia->dev_id = ce;
+
+	writel(0, base + TIMER_CTRL);
+
+	ret = setup_irq(irq, ia);

Use request_irq here, that will save some extra code in this driver.

+	if (ret) {
+		pr_err("failed to setup irq: %d\n", ret);
+		goto err_setup_irq;
+	}
+
+	clockevents_config_and_register(&ce->clkevt, rate, 0xf, 0xffffffff);
+
+	return 0;
+
+err_setup_irq:
+	kfree(ia);
+err_ia_alloc:
+	kfree(ce);
+err_ce_alloc:
+err_get_irq:
+	iounmap(base);
+err_iomap:
+	clk_disable_unprepare(clk);
+err_clk_enable:
+	clk_put(clk);
+err_clk_get:
+	return ret;
+}
+
+static int mps2_clocksource_init(struct device_node *np)

__init annotation.

+{
+	void __iomem *base;
+	struct clk *clk;
+	u32 rate;
+	int ret;
+	const char *name = "mps2-clksrc";
+
+	ret = of_property_read_u32(np, "clock-frequency", &rate);
+

extra line.

+	if (ret) {
+		clk = of_clk_get(np, 0);
+		if (IS_ERR(clk)) {
+			ret = PTR_ERR(clk);
+			pr_err("failed to get clock for clocksource: %d\n", ret);
+			goto err_clk_get;
+		}
+
+		ret = clk_prepare_enable(clk);
+		if (ret) {
+			pr_err("failed to enable clock for clocksource: %d\n", ret);
+			clk_put(clk);
+			goto err_clk_enable;
+		}
+
+		rate = clk_get_rate(clk);
+	}
+
+	base = of_iomap(np, 0);
+	if (!base) {
+		ret = -EADDRNOTAVAIL;
+		pr_err("failed to map register for clocksource: %d\n", ret);
+		goto err_iomap;
+	}
+
+	writel(0, base + TIMER_CTRL);
+
+	writel(0xffffffff, base + TIMER_VALUE);
+	writel(0xffffffff, base + TIMER_RELOAD);
+
+	writel(TIMER_CTRL_ENABLE, base + TIMER_CTRL);

A comment would help to understand the above 4 lines.

+	ret = clocksource_mmio_init(base + TIMER_VALUE, name,
+				    rate, 200, 32,
+				    clocksource_mmio_readl_down);
+	if (ret) {
+		pr_err("failed to init clocksource: %d\n", ret);
+		goto err_clocksource_init;
+	}
+
+	sched_clock_base = base;
+	sched_clock_register(mps2_sched_read, 32, rate);
+
+	return 0;
+
+err_clocksource_init:
+	iounmap(base);
+err_iomap:
+	clk_disable_unprepare(clk);
+err_clk_enable:
+	clk_put(clk);
+err_clk_get:
+	return ret;
+

extra line.

+}
+
+static void __init mps2_timer_init(struct device_node *np)
+{
+	static int clksrc;
+
+	if (!clksrc && !mps2_clocksource_init(np))
+		clksrc = 1;
+	else
+		mps2_clockevents_init(np);

That assumes the clocksource is defined before the clockevents in the 
DT. If it is not the case, the mps2_clocksource_init will fail (and spit 
errors) and mps2_clockevents_init() won't be called.

+}
+
+CLOCKSOURCE_OF_DECLARE(mps2_timer, "arm,mps2-timer", mps2_timer_init);

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