Re: [PATCH v6 1/6] ARM: make register_current_timer_delay() accessible after init

["Russell King (Oracle)" <linux@armlinux.org.uk>]

On Thu, Nov 20, 2025 at 06:42:29PM +0000, Will McVicker wrote:
> The function register_current_timer_delay() is called from the
> exynos_mct clocksource driver at probe time. In the event that the
> exynos_mct driver is probed deferred or the platform manually unbinds
> and rebinds the driver we need this function available. So drop the
> __init tag.

First question. Why.

Second, have you analysed the code to check that you _can_ call this
after init time?

Let's look at the code:

        if (!delay_calibrated && (!delay_res || (res < delay_res))) {
        } else {
                pr_info("Ignoring duplicate/late registration of read_current_ti
mer delay\n");
        }

So, if delay_calibrated is set, then this will fail. When is that set?
It's set by calibrate_delay_is_known() and calibration_delay_done().
When are these called? Basically after calibrate_delay() has finished.
When is calibrate_delay() called? It's called by start_kernel(), while
the init sections are still present.

So, calling this _after_ the init sections has been freed will result
in the above pr_info() printed and this function doing *nothing*.
So it's utterly pointless to call if the init sections have been freed.

Please find a different solution.

-- 
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