On 06/14/2016 11:52 AM, Neil Armstrong wrote:

Hi Daniel,

Hi Neil,

[ ... ]

quoted

quoted

+config OXNAS_RPS_TIMER

    config OXNAS_RPS_TIMER "bla bla" if COMPILE_TEST

OK

Shoud I also add CLKSRC_OF ?

Yes, right.

quoted

quoted

+	bool
+	select CLKSRC_MMIO
+	help
+	  This enables support for the Oxford Semiconductor OXNAS RPS timers.
+

@@ -0,0 +1,270 @@
+/*
+ * drivers/clocksource/timer-oxnas-rps.c
+ *
+ * Copyright (C) 2009 Oxford Semiconductor Ltd
+ * Copyright (C) 2013 Ma Haijun <mahaijuns@gmail.com>

What are these two copyrights ?

[ ... ]

This driver is based from a driver from the OX820 sdk from Oxford and modified by Ma Haijun, thus the copyrights.

Ok.

quoted

quoted

+static void __init oxnas_rps_timer_init(struct device_node *np)
+{
+	struct oxnas_rps_timer *rps;
+	void __iomem *base;
+	int ret;
+
+	rps = kzalloc(sizeof(*rps), GFP_KERNEL);
+	if (WARN_ON(!rps))

It is pointless to add a WARN_ON, kzalloc already does that on failure.

quoted

+		return;
+
+	rps->clk = of_clk_get(np, 0);
+	if (WARN_ON(IS_ERR(rps->clk)))
+		return;

[....]

quoted

quoted

+		goto err;
+
+	oxnas_rps_clockevent_init(rps);
+	oxnas_rps_clocksource_init(rps);
+
+	return;

err_iounmap:
	iounmap(base);

err_clk_unprepare:
	clk_unprepare(rps->clk)

err_clk_put:

quoted

+	clk_put(rps->clk);
+	kfree(rps);
+}

Regarding the current work I am doing to change the init function to return
an error in case of failure, can you do proper error handling in this
function and rollback ?

1. replace WARN_ON by a pr_err
2. make oxnas_rps_clockevent_init and oxnas_rps_clocksource_init to return
an error code

It can be done.

quoted

3. rollback clockevent or clocksource if one fails.

Sure, but as for 4.6, it seems neither sched_clock_register, clocksource_mmio_init or clockevents_config_and_register can be reverted !
What should I do ?

Just try to do the best effort.

eg.

ret = oxnas_rps_clockevent_init(rps);
if (ret)
	goto err_...

ret = oxnas_rps_clocksource_init(rps);
if (ret)
	goto err_...

If the function themselves just return 0, it is fine for me.

I initiated a process to cleanup and factor out the clocksource / 
clockevents, so any changes being able to rollback will help in this 
process.

   -- Daniel



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