On 02/02/16 13:04, Thomas Gleixner wrote:
> On Tue, 2 Feb 2016, Vladimir Murzin wrote:
>> +static int __init mps2_clockevent_init(struct device_node *np)
>> +{
>> + void __iomem *base;
>> + struct clk *clk;
>> + struct clockevent_mps2 *ce;
>> + u32 rate;
>> + int irq, ret;
>> + const char *name = "mps2-clkevt";
>> +
>> + ret = of_property_read_u32(np, "clock-frequency", &rate);
>> + 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);
>> + }
>
> So in case that "clock-frequency" is available in DT, what enables and
> configures the clock?
They are fixed-clock, so I ended up this *cough* mess *cough* shortcut.
I'd be glad if you share your thoughts what is preferred way to cope
with it (is it worth to do at all?)
>
>> +err_ia_alloc:
>> + kfree(ce);
>> +err_ce_alloc:
>> +err_get_irq:
>> + iounmap(base);
>> +err_iomap:
>> + clk_disable_unprepare(clk);
>
> clk is not initialized when "clock-frequency" is available in DT. The compiler
> should have told you ....
Shame on me, I've completely messed it up :( Thanks for pointing at it,
I'll fix this an other places you pointed at...
>
>> +err_clk_enable:
>> + clk_put(clk);
>
> Put without get ....
or double clk_put() if clk_prepare_enable() failed... shame, shame, shame
>
>> +static int __init mps2_clocksource_init(struct device_node *np)
>> +{
>> + void __iomem *base;
>> + struct clk *clk;
>> + u32 rate;
>> + int ret;
>> + const char *name = "mps2-clksrc";
>> +
>> + ret = of_property_read_u32(np, "clock-frequency", &rate);
>> + 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);
>> + }
>
> Same problem as above.
>
>> +err_clocksource_init:
>> + iounmap(base);
>> +err_iomap:
>> + clk_disable_unprepare(clk);
>
> Ditto.
>
>> +err_clk_enable:
>> + clk_put(clk);
>
> Ditto.
>
>> +err_clk_get:
>> + return ret;
>> +}
>> +
>> +static void __init mps2_timer_init(struct device_node *np)
>> +{
>> + static int has_clocksource, has_clockevent;
>> + int ret;
>> +
>> + if (!has_clocksource) {
>> + ret = mps2_clocksource_init(np);
>> + if (!ret) {
>> + has_clocksource = 1;
>> + return;
>> + }
>> + }
>> +
>> + if (!has_clockevent) {
>> + ret = mps2_clockevent_init(np);
>> + if (!ret) {
>> + has_clockevent = 1;
>> + return;
>> + }
>> + }
>
> You take randomly the first timer as clocksource and the second one as
> clockevent. If clocksource init fails, you try to install it as clockevent.
>
> Sorry, but I really cannot follow the logic here.
>
It has been done as a response on Daniel's comment [1]. I'm quite happy
to get known what init sequence is expected here.
[1]
http://lists.infradead.org/pipermail/linux-arm-kernel/2015-November/388223.html
Thanks for your time, Thomas!
Vladimir
> Thanks,
>
> tglx
>
>
>
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