On 04/03/2013 03:34 PM, Rob Herring wrote: > On 04/03/2013 01:22 PM, Stephen Warren wrote: >> On 04/03/2013 07:28 AM, Rob Herring wrote: >>> On 04/03/2013 06:32 AM, Joseph Lo wrote: >>>> Architected timer is the local timer for Cortex-A15. Adding the support >>>> for Tegra. >>>> >>>> Cc: John Stultz <john.stultz@xxxxxxxxxx> >>>> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> >>>> Signed-off-by: Joseph Lo <josephl@xxxxxxxxxx> >>> >>> My patch series to add CLOCKSOURCE_OF_DECLARE support to arch timer and >>> sched_clock enhancements will make this unnecessary: >>> >>> http://www.spinics.net/lists/arm-kernel/msg234597.html >>> >>> Testing would be appreciated. >> >> Joseph (or Rob), what's the benefit of this change; what works with it >> and/or what breaks without it? > > I assume you mean Joseph's change. Yes. > Well, it enables local timers on A15. > But mine will too for Tegra if you have the arch timer in the dtb. Well, I meant what benefit would I see from enabling them, rather than using the Tegra-specific timers as I believe is currently happening. >> Rob, if I did apply this change, and you also apply that series of >> yours, what is the result: compile-time breakage, run-time breakage, >> just some redundant code that needs to be removed again? > > Compile-time breakage as the functions called here are being removed. OK, I definitely won't apply Joseph's patch then. Aside from that, I took the git branch you mentioned in the patch you linked to above, merged it into my dev tree, updated my bootloader to actually initialize the TSC correctly, and I see the following during boot, so I guess that's enough for: Tested-by: Stephen Warren <swarren@xxxxxxxxxx> on your patches. > [ 0.000000] sched_clock: 32 bits at 1000kHz, resolution 1000ns, wraps every 4294967ms > [ 0.000000] Architected local timer running at 12.00MHz (virt). > [ 0.000000] Switching to timer-based delay loop > [ 117.431229] Calibrating delay loop (skipped), value calculated using timer frequency.. 24.00 BogoMIPS (lpj=120000) > [ 117.987221] Switching to clocksource arch_sys_counter -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
