From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kumar Gala Subject: Re: [RFC PATCH 0/5] Add smp booting support for Qualcomm ARMv8 SoCs Date: Fri, 10 Apr 2015 10:24:46 -0500 Message-ID: <493B15F8-0EBE-4633-9604-671EF403F36E@codeaurora.org> References: <1428601031-5366-1-git-send-email-galak@codeaurora.org> <20150410100529.GA6854@e104818-lin.cambridge.arm.com> Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\)) Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20150410100529.GA6854-M2fw3Uu6cmfZROr8t4l/smS4ubULX0JqMm0uRHvK7Nw@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Catalin Marinas Cc: linux-arm-msm , Device Tree Mailing List , Abhimanyu Kapur , Will Deacon , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, arm-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: devicetree@vger.kernel.org On Apr 10, 2015, at 5:05 AM, Catalin Marinas = wrote: > On Thu, Apr 09, 2015 at 12:37:06PM -0500, Kumar Gala wrote: >> This patch set adds support for SMP boot on the MSM8x16 family of Qu= alcomm SoCs. >>=20 >> To support SMP on the MSM8x16 SoCs we need to add ARMv8/64-bit SCM i= nterfaces to >> setup the boot/release addresses for the secondary CPUs. In additio= n we need >> a uniquie set of cpu ops. I'm aware the desired methods for booting= secondary >> CPUs is either via spintable or PSCI. However, these SoCs are shipp= ing with a >> firmware that does not support those methods. >=20 > And the reason is? Some guesses: >=20 > a) QC doesn't think boot interface (and cpuidle) standardisation is > worth the effort (to put it nicely) > b) The hardware was available before we even mentioned PSCI > c) PSCI is not suitable for the QC's SCM interface > d) Any combination of the above >=20 > I strongly suspect it's point (a). Should we expect future QC hardwar= e > to do the same? >=20 > You could argue the reason was (b), though we've been discussing PSCI > for at least two years and, according to QC press releases, MSM8916 > started sampling in 2014. >=20 > The only valid reason is (c) and if that's the case, I would expect a > proposal for a new firmware interface protocol (it could be PSCI-base= d), > well documented, that can be shared with others that may encounter th= e > same shortcomings. >=20 > --=20 > Catalin Does it matter? I=92ve always felt the kernel was a place of inclusion= =2E Qualcomm choose for whatever reason to not use PSCI or spin table.= You don=92t like it, I might not like it, but it is what it is. - k --=20 Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora For= um, a Linux Foundation Collaborative Project -- To unsubscribe from this list: send the line "unsubscribe devicetree" i= n the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html