From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752925AbbERJFJ (ORCPT ); Mon, 18 May 2015 05:05:09 -0400 Received: from down.free-electrons.com ([37.187.137.238]:45965 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752568AbbERJFE (ORCPT ); Mon, 18 May 2015 05:05:04 -0400 Date: Mon, 18 May 2015 11:04:17 +0200 From: Maxime Ripard To: Nicolas Pitre Cc: Ian Campbell , wens@csie.org, Dave Martin , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-sunxi@googlegroups.com Subject: Re: [linux-sunxi] [RFC 0/7] ARM: sun9i: SMP support with Multi-Cluster Power Management Message-ID: <20150518090417.GO4004@lukather> References: <1431583811-25780-1-git-send-email-wens@csie.org> <1431770926.5748.41.camel@hellion.org.uk> <20150517143816.GJ4004@lukather> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="is+7rTG+pgz69fux" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --is+7rTG+pgz69fux Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi Nicolas, On Mon, May 18, 2015 at 01:19:18AM -0400, Nicolas Pitre wrote: > On Sun, 17 May 2015, Maxime Ripard wrote: >=20 > > Hi Ian, > >=20 > > On Sat, May 16, 2015 at 11:08:46AM +0100, Ian Campbell wrote: > > > On Thu, 2015-05-14 at 14:10 +0800, Chen-Yu Tsai wrote: > > > > This is my attempt to support SMP and CPU hot plugging on the Allwi= nner > > > > A80 SoC. The A80 is a big.Little processor with 2 clusters of 4x Co= rtex-A7 > > > > and 4x Cortex-A15 cores. > > >=20 > > > I thought there was a preference these days to support this sort of > > > thing via support PSCI in the firmware, which allows for other things > > > such as non-secure-world etc. > >=20 > > Yes, it is the preferred way. Meaning that if someone wants to do that > > work, he's very much welcome and encouraged to do so. But if no one's > > doing it, then we still have to have a way to bringup the secondary > > CPUs. >=20 > And doing so in the kernel (at least initially) is simpler, and so much= =20 > easier to fix when it is broken. We've seen a few systems already where= =20 > power management is crippled because no one is able/allowed/willing to=20 > fix the broken firmware. To be fair, our platform support is done by hobbyist, and our only implementation of PSCI is done through mainline u-boot, which means we have an easy way to fix any issue we might have, and that it's possible, otherwise we wouldn't have it at all. Maxime --=20 Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com --is+7rTG+pgz69fux Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJVWasRAAoJEBx+YmzsjxAgwH0P/ig1toYRK0P4FYDOxcc6K6n3 aw7aLx3yXKAyxSHWnfMofPn0aW0areQcyc3pFZSgw0DEmR1h2B+KSHIJucDrSxBi p69pz1YYxh0PhEjkWNOcOPrux5Og1+PsJzgwXBN2+G63utyTelJLyRfCBzyDJqy+ moy19rb10w84Lcu2wu53XcVzsl/FDsKQ33GxZ0jJkvDBZWx/I/4jVyZFkJAtEpYj bXlIga9dheF7HMzUFE4SuaxY7H/hYtE7JeL03lkdQ87M4ksSp3veBN0vGJ1lDAWL MonAwDwlWbMMb8n6HDOsGNnjDHZjCa753bvYQzUHhXW0eEoE8Tv7klZ/rOxWwGc0 Se/5RvLgL4fZnHSgLxmBHjvaAbPia5rh2IRvWU/fFWp+cxIR8ymSM47XPMnZkDvl HcIuHG/ShgGpD7Sp/fg13V5vCi+Gxo1tV9rrc69ibFB0qT1vUbS0OW1VamZgTjLN djlL59dYNjkjXjbHoC2AtsdnKgE9hSYixbtM6WJxCvHmXLh3+stK6O1WerYQfGGa k7Si3J2XneQhtZ8qtOxb+xZsos10nI4W8I7mtqO4GI1yuc/tyNr/9WdpIRpXgLf9 rGXH/FDmzO9/3OesVzvn15N4DmE27XXE2O/GLQPeD650XNAQ9jxvgvT6mAIND74t 26ThN4ddR4MoB51IpMRd =1sE6 -----END PGP SIGNATURE----- --is+7rTG+pgz69fux--