On 04/26/2016 07:02 PM, Liviu Dudau wrote: > On Tue, Apr 26, 2016 at 06:28:52PM +0300, Grygorii Strashko wrote: > > Hi Grygorii, > > First time I'm seeing this patch, so I have a few questions, mostly > related to the commit message: Hm. You are in cc for RFC. Sry, forgot to add link [1]. > >> This patch intended to fix following cases: >> - SoC-A has ARM GT, defines DT node for ARM GT and selects >> ARM_GLOBAL_TIMER statically in Kconfig file. SoC-B has ARM GT and >> defines DT node for ARM GT, but do not selects ARM_GLOBAL_TIMER >> statically in Kconfig file. In case of multiplatform build ARM GT will >> be implicitly enabled for SoC-B. > > Well, SoC-B has the GT *and* the DT node, so what is the problem with > enabling it for SoC-B? If there are reasons not to use the Global Timer > on SoC-B, surely a better option would be to mark it in DT with status = "disabled"; This was rejected [2]. DT describes HW and if it is functional the status = "disabled" is not good choice. ARM GT can't be used as clocksource/sched_clock/clockevent when CPUFreq or CPUIdle are enabled :(, and this is Linux specific functionality and not HW description. > >> >> - There is no way to disable ARM GT without modifying Kconfig file, >> once ARM_GLOBAL_TIMER is selected statically in Kconfig file. > > What about disabling the DT node? > > Not sure I properly understand the problem you are trying to solve here. I'd like to have way to enable/disable ARM GT without modifying Kernel sources (Kconfig specifically) which is now impossible. > >> >> Hence, fix above case by defining both HAVE_ARM_GLOBAL_TIMER and >> ARM_GLOBAL_TIMER as recommended by 'Adding common features and make >> the usage configurable' section in kconfig-language.txt. All places in >> ARM folder where ARM_GLOBAL_TIMER was used now replaced on >> HAVE_ARM_GLOBAL_TIMER. > > I'm OK with the way you have changed ARM_GLOBAL_TIMER from a sticky config > option to a selectable one, but I would like more details on the problem > this was causing you. > The same HW (board) could be used with PM features enabled (power saving) and disabled (-RT). Without this change it will require to have and maintain two branches, but with it - just separate defconfig. [1] http://lists.infradead.org/pipermail/linux-rockchip/2016-February/007159.html [2] http://www.spinics.net/lists/devicetree/msg102918.html > >> >> Cc: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx> >> Cc: Florian Fainelli <f.fainelli@xxxxxxxxx> >> Cc: Russell King <linux@xxxxxxxxxxxxxxxx> >> Cc: Wei Xu <xuwei5@xxxxxxxxxxxxx> >> Cc: Shawn Guo <shawnguo@xxxxxxxxxx> >> Cc: Sascha Hauer <kernel@xxxxxxxxxxxxxx> >> Cc: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxx> >> Cc: Maxime Coquelin <maxime.coquelin@xxxxxx> >> Cc: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> >> Cc: Liviu Dudau <liviu.dudau@xxxxxxx> >> Cc: Sudeep Holla <sudeep.holla@xxxxxxx> >> Cc: Jun Nie <jun.nie@xxxxxxxxxx> >> Cc: Michal Simek <michal.simek@xxxxxxxxxx> >> Cc: Jesper Nilsson <jesper.nilsson@xxxxxxxx> >> Cc: Lars Persson <lars.persson@xxxxxxxx> >> Cc: Mike Looijmans <mike.looijmans@xxxxxxxx> >> Acked-by: Sören Brinkmann <soren.brinkmann@xxxxxxxxxx> >> Acked-by: Moritz Fischer <moritz.fischer@xxxxxxxxx> >> Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx> >> --- >> Changes is v1: >> - updated mach-artpec >> - rebased on top of tip: timers/core >> commit: 86d3473 time: Introduce do_sys_settimeofday64() >> >> arch/arm/mach-artpec/Kconfig | 2 +- >> arch/arm/mach-bcm/Kconfig | 4 ++-- >> arch/arm/mach-hisi/Kconfig | 2 +- >> arch/arm/mach-imx/Kconfig | 2 +- >> arch/arm/mach-rockchip/Kconfig | 2 +- >> arch/arm/mach-sti/Kconfig | 2 +- >> arch/arm/mach-uniphier/Kconfig | 2 +- >> arch/arm/mach-vexpress/Kconfig | 2 +- >> arch/arm/mach-zx/Kconfig | 2 +- >> arch/arm/mach-zynq/Kconfig | 2 +- >> drivers/clocksource/Kconfig | 7 ++++++- >> 11 files changed, 17 insertions(+), 12 deletions(-) >> >> diff --git a/arch/arm/mach-artpec/Kconfig b/arch/arm/mach-artpec/Kconfig >> index 6cbe5a2..6cbca77 100644 >> --- a/arch/arm/mach-artpec/Kconfig >> +++ b/arch/arm/mach-artpec/Kconfig >> @@ -9,7 +9,7 @@ config MACH_ARTPEC6 >> depends on ARCH_MULTI_V7 >> select ARM_AMBA >> select ARM_GIC >> - select ARM_GLOBAL_TIMER [...] -- regards, -grygorii -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
