From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756212Ab3KHBDu (ORCPT ); Thu, 7 Nov 2013 20:03:50 -0500 Received: from mx0a-0016f401.pphosted.com ([67.231.148.174]:45921 "EHLO mx0a-0016f401.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754717Ab3KHBDr (ORCPT ); Thu, 7 Nov 2013 20:03:47 -0500 Date: Fri, 8 Nov 2013 08:58:30 +0800 From: Jisheng Zhang To: Sebastian Hesselbarth CC: Arnd Bergmann , Russell King , Kevin Hilman , "linux-kernel@vger.kernel.org" , Olof Johansson , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH v3 9/9] ARM: add initial support for Marvell Berlin SoCs Message-ID: <20131108085830.5368c92b@xhacker> In-Reply-To: <527C049B.4030608@gmail.com> References: <1381235073-17134-1-git-send-email-sebastian.hesselbarth@gmail.com> <20131107134033.59bd127a@xhacker> <527B67A1.3020803@gmail.com> <201311071720.47489.arnd@arndb.de> <527C049B.4030608@gmail.com> X-Mailer: Claws Mail 3.9.2 (GTK+ 2.24.22; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:5.10.8794,1.0.431,0.0.0000 definitions=2013-11-07_08:2013-11-08,2013-11-07,1970-01-01 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=7.0.1-1305240000 definitions=main-1311070213 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Dear Sebastian, On Thu, 7 Nov 2013 13:22:35 -0800 Sebastian Hesselbarth wrote: > On 11/07/2013 05:20 PM, Arnd Bergmann wrote: > > On Thursday 07 November 2013, Sebastian Hesselbarth wrote: > >> Actually, IIRC smp_twd does not compile without SMP set, so the above > >> should at least be 'HAVE_ARM_TWD if SMP'. If you shrink MULTI_V7 down > >> to non-SMP cores, you can disable it and it will fail to compile. > > > > If there are UP-systems for which TWD is the best clocksource, we should > > probably fix the code to allow that configuration. IIRC there were already > > patches recently in this area, maybe it's already solved. The problems is twd is not mandatory in CA9 UP system, so it may not exist. However, I got answers from soc people, the BG2CD does configured and enabled TWD. so we are lucky and can add HAVE_TWD for BG2CD. > > I just tried barebox bootloader to use TWD as timer on berlin2cd and it > perfectly works, i.e. with time related commands I can see the timer > register decreasing. So the timer is available on this UP SoC. Yep. It is available. > > As said before, compiling linux without CONFIG_SMP but with > CONFIG_HAVE_ARM_TWD gives: > > warning: (SOC_OMAP5 && ARCH_ROCKCHIP && ARCH_SHMOBILE_MULTI && > MACH_BERLIN_BG2 && MACH_BERLIN_BG2CD) selects HAVE_ARM_TWD which has > unmet direct dependencies (SMP) > > and > > arch/arm/kernel/smp_twd.c: In function 'twd_local_timer_of_register': > arch/arm/kernel/smp_twd.c:391: error: 'setup_max_cpus' undeclared (first > use in this function) > arch/arm/kernel/smp_twd.c:391: error: (Each undeclared identifier is > reported only once > arch/arm/kernel/smp_twd.c:391: error: for each function it appears in.) > make[1]: *** [arch/arm/kernel/smp_twd.o] Error 1 > > I haven't looked deeper into this, but I guess it will not be hard > to make ARM_TWD independent of SMP. > > Sebastian >