From mboxrd@z Thu Jan 1 00:00:00 1970 From: sboyd@codeaurora.org (Stephen Boyd) Date: Mon, 09 Feb 2015 11:01:10 -0800 Subject: Delays, clocks, timers, hrtimers, etc In-Reply-To: <54D576B1.4000001@free.fr> References: <54C8E125.3070905@free.fr> <54D52F84.9050600@free.fr> <266c7b1ff2d1a8ba0ae4866f4fb4eca5@agner.ch> <54D576B1.4000001@free.fr> Message-ID: <54D903F6.3050608@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 02/06/15 18:21, Mason wrote: > > > config HAVE_ARM_TWD > bool > depends on SMP > select CLKSRC_OF if OF > help > This options enables support for the ARM timer and watchdog unit > > One problem I see is that HAVE_ARM_TWD depends on SMP... > > One of the systems I want to support is UP (single-core Cortex A9). > Does that mean I should use an SMP kernel even for that system? > Or is there a different subsystem for UP systems? I don't see any problem with the TWD dropping the dependency on SMP. The code should work the same on a UP configuration and if that's the only timer you have that can deliver interrupts to your processor then it would be required. You'd still need a clocksource though, which the TWD doesn't provide. -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project