From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Grall Subject: Re: [PATCH] xen/arm: Propagate clock-frequency to DOMU if present in the DT timer node Date: Thu, 4 Jun 2015 00:24:03 +0100 Message-ID: <556F8C93.4000703@citrix.com> References: <1433342886-14790-1-git-send-email-julien.grall@citrix.com> <4EE5B48738DDED408878C97C8E050A8B1D7A3B47@SJEXCHMB05.corp.ad.broadcom.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta14.messagelabs.com ([193.109.254.103]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1Z0I13-0002eb-Qf for xen-devel@lists.xenproject.org; Wed, 03 Jun 2015 23:24:09 +0000 In-Reply-To: <4EE5B48738DDED408878C97C8E050A8B1D7A3B47@SJEXCHMB05.corp.ad.broadcom.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: "Chris (Christopher) Brand" , "xen-devel@lists.xenproject.org" Cc: "ian.jackson@eu.citrix.com" , "stefano.stabellini@citrix.com" , "tim@xen.org" , "ian.campbell@citrix.com" , "wei.liu2@citrix.com" List-Id: xen-devel@lists.xenproject.org On 03/06/2015 23:45, Chris (Christopher) Brand wrote: > Hi Julien, Hi Chris, >> When the property "clock-frequency" is present in the DT timer node, it means that the bootloader/firmware didn't correctly configured the >> CNTFRQ/CNTFRQ_EL0 on each processor. > I will test this patch, but it doesn't apply cleanly to the version of Xen I'm currently using, so I need to update that first. It's based on the latest staging. > I also looked at whether it would be possible to set the CNTFRQ register in the other cores when they come up. Eventually, I think we should do this in the (platform-specific) PSCI code. There doesn't seem to be a suitable hook in the platform-specific Xen code - it looks like all the code there related to bringing up secondary cores runs on the primary. CNTFRQ is read-only in the hypervisor when the platform supports EL3 (i.e secure monitor). So it has to be done either by the bootloader or by the firmware. Regards, -- Julien Grall