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 > > 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 /var/log/kern.log file use a absolute time, like "Nov 29 12:26:13", as well as relative time in seconds and microseconds since startup , like "[1263900.984287] Is the relative time calculated by the clocksource driver module (tsc or acpi_pm)? Which module is responsible for resulting in the absolute time? Is absolute time synchronized across multiple systems connected on the network? > > > -- > <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 -- Thanks, Sekhar _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
