From mboxrd@z Thu Jan 1 00:00:00 1970 From: Al Stone Subject: Re: [RFC PATCH 5/5] arm64: qcom: add cpu operations Date: Wed, 15 Apr 2015 10:29:33 -0600 Message-ID: <552E91ED.2080805@redhat.com> References: <1428601031-5366-1-git-send-email-galak@codeaurora.org> <1428601031-5366-6-git-send-email-galak@codeaurora.org> <20150414162953.GL28709@leverpostej> <552D9A37.6070107@redhat.com> <20150415090425.GA2866@leverpostej> <20150415145350.GB22741@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20150415145350.GB22741@localhost> Sender: linux-kernel-owner@vger.kernel.org To: Catalin Marinas , Mark Rutland Cc: "devicetree@vger.kernel.org" , "linux-arm-msm@vger.kernel.org" , Kumar Gala , Will Deacon , "linux-kernel@vger.kernel.org" , "arm@kernel.org" , Abhimanyu Kapur , "linux-arm-kernel@lists.infradead.org" List-Id: linux-arm-msm@vger.kernel.org On 04/15/2015 08:53 AM, Catalin Marinas wrote: > On Wed, Apr 15, 2015 at 10:04:25AM +0100, Mark Rutland wrote: >> On Tue, Apr 14, 2015 at 11:52:39PM +0100, Al Stone wrote: >>> On 04/14/2015 10:29 AM, Mark Rutland wrote: >>>>> diff --git a/Documentation/devicetree/bindings/arm/cpus.txt b/Documentation/devicetree/bindings/arm/cpus.txt >>>>> index 8b9e0a9..35cabe5 100644 >>>>> --- a/Documentation/devicetree/bindings/arm/cpus.txt >>>>> +++ b/Documentation/devicetree/bindings/arm/cpus.txt >>>>> @@ -185,6 +185,8 @@ nodes to be present and contain the properties described below. >>>>> be one of: >>>>> "psci" >>>>> "spin-table" >>>> >>>> In the case of these two, there's documentation on what the OS, FW, and >>>> HW are expected to do. There's a PSCI spec, and spin-table is documented >>>> in booting.txt (which is admittedly not fantastic). >>>> [snip...] >>> >>> Perhaps a side topic, but I thought spin-table was being actively discouraged >>> for arm64. Forgive me if I missed the memo, but is that not correct? >> >> We prefer that people implement PSCI, and if they must use spin-table, >> each CPU has its own release address. >> >> However, we don't want implementation-specific mechanisms, and >> spin-table is preferable to these. > > An important aspect is that with spin-table you don't get CPU off or > suspend and some kernel functionality will be missing (kexec being one > of them). > Thanks for the clarifications. I misunderstood; I knew PSCI was preferred but somehow had it in my head that spin-table was just a non-starter. -- ciao, al ----------------------------------- Al Stone Software Engineer Red Hat, Inc. ahs3@redhat.com -----------------------------------