Re: [meta-xilinx] Zynq TTC usage by Linux

2016-10-25 Thread Edward Wingate
On Tue, Oct 25, 2016 at 12:01 AM, Mike Looijmans wrote: > Usually the term "real time" is applied to too many things. For example, > your desktop PC experiences latencies of over 1 ms for typical interrupts, > but it still functions fine when running various audio and

Re: [meta-xilinx] Zynq TTC usage by Linux

2016-10-22 Thread Mike Looijmans
One of the TTCs used to be used for clock source. This should still be the case if you use dynamic clocks, because the ARM timer is fixed to the CPU speed and does not handle frequency changes (though I think it should be possible to fix this purely in software, no-one seems to care though).

Re: [meta-xilinx] Zynq TTC usage by Linux

2016-10-21 Thread Jiaying Liang
HI Edward, > -Original Message- > From: meta-xilinx-boun...@yoctoproject.org [mailto:meta-xilinx- > boun...@yoctoproject.org] On Behalf Of Edward Wingate > Sent: Friday, October 21, 2016 12:42 PM > To: Nathan Rossi > Cc: meta-xilinx@yoctoproject.org > Subject: Re: [

Re: [meta-xilinx] Zynq TTC usage by Linux

2016-10-21 Thread Edward Wingate
On Fri, Oct 21, 2016 at 12:26 AM, Nathan Rossi wrote: > This is informing that the ttc device is probed and setup as a > clocksource device. Althought it is probably not used. > You can also check to see what is currently in use: cat >

Re: [meta-xilinx] Zynq TTC usage by Linux

2016-10-20 Thread Edward Wingate
It looks like Linux is aware of TTC0 at least, from dmesg: clocksource: ttc_clocksource: mask: 0x max_cycles: 0x, max_idle_ns: 537538477 ns ps7-ttc #0 at 9e808000, irq=18 And it is allocated with virtual memory mapping (/proc/vmallocinfo): 0x9e808000-0x9e80a0008192 of_iomap+0x2c/0x34