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Sat, 15 Feb 2020 13:41:15 +0100 Received: from euls16034.sgp.st.com (euls16034.sgp.st.com [10.75.44.20]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id 1F7DA10002A; Sat, 15 Feb 2020 13:41:07 +0100 (CET) Received: from Webmail-eu.st.com (sfhdag7node3.st.com [10.75.127.21]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id CBB7A2B39E6; Sat, 15 Feb 2020 13:41:07 +0100 (CET) Received: from SFHDAG3NODE3.st.com (10.75.127.9) by SFHDAG7NODE3.st.com (10.75.127.21) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Sat, 15 Feb 2020 13:41:07 +0100 Received: from SFHDAG3NODE3.st.com ([fe80::3507:b372:7648:476]) by SFHDAG3NODE3.st.com ([fe80::3507:b372:7648:476%20]) with mapi id 15.00.1347.000; Sat, 15 Feb 2020 13:41:07 +0100 From: Benjamin GAIGNARD To: Greg KH , Linus Walleij Subject: Re: [PATCH v2 2/7] bus: Introduce firewall controller framework Thread-Topic: [PATCH v2 2/7] bus: Introduce firewall controller framework Thread-Index: AQHV1fD3WqS5xyjWNkazyajQl95bjqgAKU6AgAANnwCAAARlAIAAO2IAgADdioCAAALMAIAAF6SAgAL4AQCAAAg2AIAWdYKAgABdzYCAAPuHAA== Date: Sat, 15 Feb 2020 12:41:07 +0000 Message-ID: <409eb745-aab2-86a7-bd3a-9e8e05bed057@st.com> References: <20200128155243.GC3438643@kroah.com> <0dd9dc95-1329-0ad4-d03d-99899ea4f574@st.com> <20200128165712.GA3667596@kroah.com> <62b38576-0e1a-e30e-a954-a8b6a7d8d897@st.com> <20200129095240.GA3852081@kroah.com> <20200129111717.GA3928@sirena.org.uk> <0b109c05-24cf-a1c4-6072-9af8a61f45b2@st.com> <20200131090650.GA2267325@kroah.com> <20200214214051.GA4192967@kroah.com> In-Reply-To: <20200214214051.GA4192967@kroah.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: user-agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 x-ms-exchange-messagesentrepresentingtype: 1 x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.75.127.49] Content-ID: MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138, 18.0.572 definitions=2020-02-15_03:2020-02-14, 2020-02-15 signatures=0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200215_044140_121015_2E6693B3 X-CRM114-Status: GOOD ( 23.39 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Stephen Rothwell , Loic PALLARDY , "arnd@arndb.de" , "devicetree@vger.kernel.org" , "shawnguo@kernel.org" , "s.hauer@pengutronix.de" , "linux-kernel@vger.kernel.org" , Grant Likely , "lkml@metux.net" , "linux-imx@nxp.com" , "kernel@pengutronix.de" , "sudeep.holla@arm.com" , "fabio.estevam@nxp.com" , "stefano.stabellini@xilinx.com" , "system-dt@lists.openampproject.org" , "robh@kernel.org" , "linux-arm-kernel@lists.infradead.org" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2/14/20 10:40 PM, Greg KH wrote: > On Fri, Feb 14, 2020 at 05:05:07PM +0100, Linus Walleij wrote: >> On Fri, Jan 31, 2020 at 10:06 AM Greg KH wrote: >> >>> Why do people want to abuse the platform bus so much? If a device is on >>> a bus that can have such a controller, then it is on a real bus, use it! >> I'm not saying it is a good thing, but the reason why it is (ab)used so >> much can be found in: >> drivers/of/platform.c >> >> TL;DR: struct platform_device is the Device McDeviceFace and >> platform bus the Bus McBusFace used by the device tree parser since >> it is slightly to completely unaware of what devices it is actually >> spawning. > > > Yeah, great explaination, and I understand. DT stuff really is ok to be > on a platform bus, as that's what almost all of them are. > > But, when you try to start messing around with things like this > "firewall" says it is doing, it's then obvious that this really isn't a > DT like thing, but rather you do have a bus involved with a controller > so that should be used instead. Ok but how put in place a new bus while keeping the devices on platform bus to avoid changing all the drivers ? > > Or just filter away the DT stuff so that the kernel never even sees > those devices, which might just be simplest :) yes but we lost the possibility to change the firewall configuration at run time. I do expect to be able to describe in the DT firewall configuration and to use them at run time. That could allow, for example, to handover a HW block to the coprocessor when the main core is going to be suspended to save power. Benjamin > > thanks, > > greg k-h _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel