Hi Mark, On Thu, Jan 15, 2015 at 8:29 PM, Mark Rutland <mark.rutland@xxxxxxx> wrote: > On Wed, Jan 14, 2015 at 11:57:00PM +0000, Chanwoo Choi wrote: >> Hi Kukjin, >> >> On 01/15/2015 01:02 AM, Daniel Lezcano wrote: >> > On 01/14/2015 04:51 PM, Kukjin Kim wrote: >> >> On 01/14/15 14:33, Chanwoo Choi wrote: >> >> >> >> Hi, >> >> >> >> + Doug, Olof >> >> >> >>> This patch adds the support for Exynos 64bit SoC. The delay_timer is only used >> >>> for Exynos 32bit SoC. >> >>> >> >> Yes, the Exynos MCT(Multi-Core Timer) is 64bit timer and it is available >> >> on 64bit exynos SoC such as exynos7. But basically ARMv8 architecture is >> >> including ARM ARCH timer (ARM Generic Timer) and exynos7 also has >> >> implemented it and additionally its access is faster than using memory >> >> mapped register called SFR for MCT...so Doug submitted patch to use MCT >> >> on 32bit exynos SoCs before. >> >> I know arch_timer. As you comment, ARCH timer would be used for system timer for ARMv8. >> But, Exynos5433/Exynos7 (ARMv8) include MCT (Multi-Core Timer) IP. I checked it on >> Exynos5433/EXynos7 User-manaual and tested it. >> >> I think that exynos_mct.c should support the Exynos 64-bit SoC >> because Exynos5433/Exynos7 include already MCT (Multi-Core Timer) IP. >> >> Also, I have a problem to verify ARCH timer on Exynos SoC. Exynos User-manual never includes >> the detailed information about for ARCH timer(e.g, clock for ARCH timer). I knew that >> I can get the document of ARCH timer for ARM official site but I think it is insufficient >> to implement ARCH timer on Exynos SoC. > > What do you mean by "insufficient to implement ARCH timer"? As I knew, timer must need the source clock. The clock for ARCH timer has dependency on Exynos SoC, But I cannot find > > The architected timer is mandatory in ARMv8, and required by the arm64 > kernel. > > Additional timers may be requried if you want to put all CPUs into low > power states where the timer logic may be disabled and/or lose state, > but regardless the architected timers are necessary. > > Thanks, > Mark. > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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