From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter De Schrijver Subject: Re: Clocks used by another OS/CPU (was: Re: [RFC PATCH] clk: renesas: cpg-mssr: Add interface for critical core clocks) Date: Tue, 4 Jul 2017 10:31:37 +0300 Message-ID: <20170704073137.GG14819@tbergstrom-lnx.Nvidia.com> References: <20170630202453.eh6vaehkap3as4np@pengutronix.de> <8d86a9aa-1928-6b52-1487-d5fb9dae17f4@gmail.com> <20170701181408.yuocymwtj5dgt74d@pengutronix.de> <8d255a76-babe-312d-15b3-3474969f2410@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8BIT Return-path: Content-Disposition: inline In-Reply-To: <8d255a76-babe-312d-15b3-3474969f2410@arm.com> Sender: linux-renesas-soc-owner@vger.kernel.org To: Sudeep Holla Cc: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= , Dirk Behme , Rob Herring , Mark Rutland , "devicetree@vger.kernel.org" , Ulf Hansson , Dirk Behme , Linux PM list , "Rafael J. Wysocki" , Michael Turquette , Stephen Boyd , Linux-Renesas , Geert Uytterhoeven , Kevin Hilman , linux-clk , "linux-arm-kernel@lists.infradead.org" List-Id: devicetree@vger.kernel.org On Mon, Jul 03, 2017 at 10:17:22AM +0100, Sudeep Holla wrote: > > > On 01/07/17 19:14, Uwe Kleine-König wrote: > > Hello, > > > > On Sat, Jul 01, 2017 at 07:02:48AM +0200, Dirk Behme wrote: > > [...] > > >> > >> > >> The other problem is security related. If, at all, you have to do it the > >> other way around, then: > >> > >> Make Linux a consumer of the other CPU's (trusted/trustzone/whatever > >> secured) OS clock driver. > > Yes, that's better and is getting common on newer platforms. They have > separate M-class(or even low A-class e.g. A5/A7) processors to handle > all the system management. > > The new ARM SCMI specification[0][1] is designed to standardize the > interface. It covers the clocks in clock protocol. > Yes, however this doesn't exist on older SoCs which still have multiple CPU's Peter. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from hqemgate15.nvidia.com ([216.228.121.64]:5388 "EHLO hqemgate15.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752204AbdGDHbw (ORCPT ); Tue, 4 Jul 2017 03:31:52 -0400 Date: Tue, 4 Jul 2017 10:31:37 +0300 From: Peter De Schrijver To: Sudeep Holla CC: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= , "Dirk Behme" , Rob Herring , Mark Rutland , "devicetree@vger.kernel.org" , Ulf Hansson , "Dirk Behme" , Linux PM list , "Rafael J. Wysocki" , Michael Turquette , Stephen Boyd , Linux-Renesas , Geert Uytterhoeven , Kevin Hilman , linux-clk , "linux-arm-kernel@lists.infradead.org" Subject: Re: Clocks used by another OS/CPU (was: Re: [RFC PATCH] clk: renesas: cpg-mssr: Add interface for critical core clocks) Message-ID: <20170704073137.GG14819@tbergstrom-lnx.Nvidia.com> References: <20170630202453.eh6vaehkap3as4np@pengutronix.de> <8d86a9aa-1928-6b52-1487-d5fb9dae17f4@gmail.com> <20170701181408.yuocymwtj5dgt74d@pengutronix.de> <8d255a76-babe-312d-15b3-3474969f2410@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Disposition: inline Content-Transfer-Encoding: 8BIT In-Reply-To: <8d255a76-babe-312d-15b3-3474969f2410@arm.com> Sender: linux-renesas-soc-owner@vger.kernel.org List-ID: On Mon, Jul 03, 2017 at 10:17:22AM +0100, Sudeep Holla wrote: > > > On 01/07/17 19:14, Uwe Kleine-K�nig wrote: > > Hello, > > > > On Sat, Jul 01, 2017 at 07:02:48AM +0200, Dirk Behme wrote: > > [...] > > >> > >> > >> The other problem is security related. If, at all, you have to do it the > >> other way around, then: > >> > >> Make Linux a consumer of the other CPU's (trusted/trustzone/whatever > >> secured) OS clock driver. > > Yes, that's better and is getting common on newer platforms. They have > separate M-class(or even low A-class e.g. A5/A7) processors to handle > all the system management. > > The new ARM SCMI specification[0][1] is designed to standardize the > interface. It covers the clocks in clock protocol. > Yes, however this doesn't exist on older SoCs which still have multiple CPU's Peter. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Tue, 4 Jul 2017 10:31:37 +0300 From: Peter De Schrijver To: Sudeep Holla CC: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= , "Dirk Behme" , Rob Herring , Mark Rutland , "devicetree@vger.kernel.org" , Ulf Hansson , "Dirk Behme" , Linux PM list , "Rafael J. Wysocki" , Michael Turquette , Stephen Boyd , Linux-Renesas , Geert Uytterhoeven , Kevin Hilman , linux-clk , "linux-arm-kernel@lists.infradead.org" Subject: Re: Clocks used by another OS/CPU (was: Re: [RFC PATCH] clk: renesas: cpg-mssr: Add interface for critical core clocks) Message-ID: <20170704073137.GG14819@tbergstrom-lnx.Nvidia.com> References: <20170630202453.eh6vaehkap3as4np@pengutronix.de> <8d86a9aa-1928-6b52-1487-d5fb9dae17f4@gmail.com> <20170701181408.yuocymwtj5dgt74d@pengutronix.de> <8d255a76-babe-312d-15b3-3474969f2410@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" In-Reply-To: <8d255a76-babe-312d-15b3-3474969f2410@arm.com> Return-Path: pdeschrijver@nvidia.com List-ID: On Mon, Jul 03, 2017 at 10:17:22AM +0100, Sudeep Holla wrote: >=20 >=20 > On 01/07/17 19:14, Uwe Kleine-K=F6nig wrote: > > Hello, > >=20 > > On Sat, Jul 01, 2017 at 07:02:48AM +0200, Dirk Behme wrote: >=20 > [...] >=20 > >> > >> > >> The other problem is security related. If, at all, you have to do it t= he > >> other way around, then: > >> > >> Make Linux a consumer of the other CPU's (trusted/trustzone/whatever > >> secured) OS clock driver. >=20 > Yes, that's better and is getting common on newer platforms. They have > separate M-class(or even low A-class e.g. A5/A7) processors to handle > all the system management. >=20 > The new ARM SCMI specification[0][1] is designed to standardize the > interface. It covers the clocks in clock protocol. >=20 Yes, however this doesn't exist on older SoCs which still have multiple CPU= 's Peter. From mboxrd@z Thu Jan 1 00:00:00 1970 From: pdeschrijver@nvidia.com (Peter De Schrijver) Date: Tue, 4 Jul 2017 10:31:37 +0300 Subject: Clocks used by another OS/CPU (was: Re: [RFC PATCH] clk: renesas: cpg-mssr: Add interface for critical core clocks) In-Reply-To: <8d255a76-babe-312d-15b3-3474969f2410@arm.com> References: <20170630202453.eh6vaehkap3as4np@pengutronix.de> <8d86a9aa-1928-6b52-1487-d5fb9dae17f4@gmail.com> <20170701181408.yuocymwtj5dgt74d@pengutronix.de> <8d255a76-babe-312d-15b3-3474969f2410@arm.com> Message-ID: <20170704073137.GG14819@tbergstrom-lnx.Nvidia.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, Jul 03, 2017 at 10:17:22AM +0100, Sudeep Holla wrote: > > > On 01/07/17 19:14, Uwe Kleine-K?nig wrote: > > Hello, > > > > On Sat, Jul 01, 2017 at 07:02:48AM +0200, Dirk Behme wrote: > > [...] > > >> > >> > >> The other problem is security related. If, at all, you have to do it the > >> other way around, then: > >> > >> Make Linux a consumer of the other CPU's (trusted/trustzone/whatever > >> secured) OS clock driver. > > Yes, that's better and is getting common on newer platforms. They have > separate M-class(or even low A-class e.g. A5/A7) processors to handle > all the system management. > > The new ARM SCMI specification[0][1] is designed to standardize the > interface. It covers the clocks in clock protocol. > Yes, however this doesn't exist on older SoCs which still have multiple CPU's Peter.