> On 12-03-16 10:54, Sören Brinkmann wrote: > > On Fri, 2016-03-11 at 14:04:43 -0800, Moritz Fischer wrote: > >> Hi Mike, > >> > >> On Fri, Mar 11, 2016 at 12:49 AM, Mike Looijmans > >> <[email protected]> wrote: > >> > >>> Hmm, just manually hacking the register values has no effect at all on > the > >>> system. So apparently some other clock is being used as the source. > >>> > >>> How can I see (and choose?) which clock is to be used? > > > > It is printed during boot. Some line with 'clocksource' in it, IIRC. I > > suspect something in /sys could tell it too. > > A bit of digging for "clocksource" in the kernel source code reveals that > the > clocksource can be switched using: > > echo ttc_clocksource > > /sys/devices/system/clocksource/clocksource0/current_clocksource > > I just wonder now how other platforms handle this, or is the CPU frequency > influencing the HR timer something that's unique to the Zynq? > >
Most have this properly solved in silicon: use a non changing clock But not everyone: http://thread.gmane.org/gmane.linux.documentation/11045/focus=11044 One could use a softcore AxiTimer and fix the whole clock dependency problem. ('any' CPU freq would be possible) However the driver for the softcore timer is in the microblaze core. It would be nice if that moved to a generic driver, giving the Zynq an easy solution for this problem Kind regards, Wouter van Gulik -- _______________________________________________ meta-xilinx mailing list [email protected] https://lists.yoctoproject.org/listinfo/meta-xilinx
