Re: [PATCH v1 02/10] clockevents/drivers: add MPS2 Timer driver

From: Daniel Lezcano
Date: Mon Dec 14 2015 - 08:36:22 EST


On 12/02/2015 10:33 AM, Vladimir Murzin wrote:
MPS2 platform has simple 32 bits general purpose countdown timers.

The driver uses the first detected timer as a clocksource and the rest
of the timers as a clockevent

Signed-off-by: Vladimir Murzin <vladimir.murzin@xxxxxxx>
---

[ ... ]

+static void clockevent_mps2_writel(u32 val, struct clock_event_device *c, u32 offset)
+{
+ writel(val, to_mps2_clkevt(c)->reg + offset);
+}

Is it possible to use writel_relaxed here ?

[ ... ]

+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) {
+ pr_warn("spuirous interrupt\n");

typo: 'spurious'

[ ... ]

+ ce = kzalloc(sizeof(struct clockevent_mps2), GFP_KERNEL);
+ if (!ce) {
+ ret = -ENOMEM;
+ pr_err("failed to allocate clockevent: %d\n", ret);

There is already a stack trace in the kernel when an allocation fails.

With the above fixed:

Acked-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>


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