On 06/12/2021 07:00, Muni Sekhar wrote: > On Sat, Dec 4, 2021 at 3:18 AM Daniel Lezcano <daniel.lezcano@xxxxxxxxxx> wrote: >> >> Hi Sekhar, >> >> On 03/12/2021 17:50, Muni Sekhar wrote: >>> Hi All, >>> >>> We have a Digital PLL with 64 bit timer counter hardware and the >>> counter is accessible from the CPU over the PCIe bus. >>> >>> Is it possible to add this timer counter hardware as new clocksource >>> driver? To do this, can someone please point me to the existing >>> reference source code(or patch) for this task. >> >> You can refer to the drivers located in drivers/clocksource > I don't see the option in menuconfig to build the clocksource driver > as a loadable kernel module, for example CONFIG_X86_PM_TIMER=m instead > of CONFIG_X86_PM_TIMER=y. > So a clocksource driver should always be part of the kernel built-in > module? Yes, that is the case today. > If so, what's the reason for that? The timer is a component needed at boot time, so a module version does really not make sense. So I would return back the question : what is the reason for a module? >> git annotate on one of the driver can give you the initial commit where >> recent submissions explain the timer internals. >> >>> Suppose if it is possible to add a new clocksource driver for this >>> hardware then does any userspace get_timestamp* API would get the time >>> from this new hardware? >> >> It should if the timer is selected as the clocksource >> >> >> -- >> <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs >> >> Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | >> <http://twitter.com/#!/linaroorg> Twitter | >> <http://www.linaro.org/linaro-blog/> Blog > > > -- <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
