From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0497AC43334 for ; Fri, 8 Jul 2022 22:09:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239070AbiGHWJv (ORCPT ); Fri, 8 Jul 2022 18:09:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38412 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229749AbiGHWJt (ORCPT ); Fri, 8 Jul 2022 18:09:49 -0400 Received: from lelv0142.ext.ti.com (lelv0142.ext.ti.com [198.47.23.249]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0D1379FE06; Fri, 8 Jul 2022 15:09:48 -0700 (PDT) Received: from fllv0034.itg.ti.com ([10.64.40.246]) by lelv0142.ext.ti.com (8.15.2/8.15.2) with ESMTP id 268M9gp8076075; Fri, 8 Jul 2022 17:09:42 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1657318182; bh=BlXwRGaPw5o1YFhTRP4d6RoP/VRJ5AKvNwGx2X9N4b4=; h=Date:From:To:CC:Subject:References:In-Reply-To; b=oTRxozMX/ckWbVGRdBl3pPKc5UiMOsUqwWT1zaHwP6SGTlvwHabcyzrAE/qRmAhC4 Yc7xFI6tvp+mRBRiCRFR64EvwIKEJb0pX6RPkjlRus7yz9dUR2iEBekWFws/5JLbzC BzxDCWu6N4YpNx95rzJbOJSdjKaJjEW3bjwmJW6E= Received: from DLEE110.ent.ti.com (dlee110.ent.ti.com [157.170.170.21]) by fllv0034.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 268M9gdY086110 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 8 Jul 2022 17:09:42 -0500 Received: from DLEE104.ent.ti.com (157.170.170.34) by DLEE110.ent.ti.com (157.170.170.21) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2308.14; Fri, 8 Jul 2022 17:09:41 -0500 Received: from lelv0326.itg.ti.com (10.180.67.84) by DLEE104.ent.ti.com (157.170.170.34) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2308.14 via Frontend Transport; Fri, 8 Jul 2022 17:09:41 -0500 Received: from localhost (ileax41-snat.itg.ti.com [10.172.224.153]) by lelv0326.itg.ti.com (8.15.2/8.15.2) with ESMTP id 268M9f0v029095; Fri, 8 Jul 2022 17:09:41 -0500 Date: Fri, 8 Jul 2022 17:09:41 -0500 From: Nishanth Menon To: Andrew Davis CC: Bryan Brattlof , Vignesh Raghavendra , Tero Kristo , Rob Herring , Krzysztof Kozlowski , , , Subject: Re: [PATCH v2 1/4] arm64: dts: ti: k3-am65-main: Disable RNG node Message-ID: <20220708220941.skpq7i7ilccw5zdt@secret> References: <20220706190838.26074-1-afd@ti.com> <20220707144400.tk3wmpeijdhuxpzv@bryanbrattlof.com> <20220707171734.e22t5rx5ux7k5kcr@magnetize> <1d6d171f-3c91-530a-27a5-c93153cb2378@ti.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <1d6d171f-3c91-530a-27a5-c93153cb2378@ti.com> User-Agent: NeoMutt/20171215 X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12:36-20220707, Andrew Davis wrote: > On 7/7/22 12:17 PM, Nishanth Menon wrote: > > On 10:01-20220707, Andrew Davis wrote: > > > On 7/7/22 9:44 AM, Bryan Brattlof wrote: > > > > Hi Andrew > > > > > > > > On July 6, 2022 thus sayeth Andrew Davis: > > > > > The hardware random number generator is used by OP-TEE and is access is > > > > > denied to other users with SoC level bus firewalls. Any access to this > > > > > device from Linux will result in firewall errors. Disable this node. > > > > > > > > > > Signed-off-by: Andrew Davis > > > > > --- > > > > > > > > > > Changes from v1: > > > > > - Added comment in dtsi file > > > > > > > > > > arch/arm64/boot/dts/ti/k3-am65-main.dtsi | 1 + > > > > > 1 file changed, 1 insertion(+) > > > > > > > > > > diff --git a/arch/arm64/boot/dts/ti/k3-am65-main.dtsi b/arch/arm64/boot/dts/ti/k3-am65-main.dtsi > > > > > index e749343accedd..9de5a8294acd6 100644 > > > > > --- a/arch/arm64/boot/dts/ti/k3-am65-main.dtsi > > > > > +++ b/arch/arm64/boot/dts/ti/k3-am65-main.dtsi > > > > > @@ -127,6 +127,7 @@ rng: rng@4e10000 { > > > > > reg = <0x0 0x4e10000 0x0 0x7d>; > > > > > interrupts = ; > > > > > clocks = <&k3_clks 136 1>; > > > > > + status = "disabled"; /* Used by OP-TEE */ > > > > > > > > Just curious about how we should document disabling nodes. I was > > > > assuming the reasoning should be described in the bindings? > > > > > > > > I would like to start disabling nodes by default in our dtsi files and > > > > enabling them in our top dts file, making it easier for others to use > > > > our device tree for a more focused purpose than our dev boards. I just > > > > didn't know where I should document why I disabled the nodes :) > > > > > > > > > > This got push-back last time this was suggested, I'll have to lookup > > > the history. IIRC we landed on the other way around, all things should > > > be described by default, then the specific board can enable/disable > > > what is not used as needed. > > > > See thread https://lore.kernel.org/linux-arm-kernel/YiizsYnKB0X9bDY2@atomide.com/ > > > > > > > > I was worried this topic would come up with this patch series and was > > > almost just going to delete the whole RNG node instead of disabling it > > > to avoid that. My reasoning for disabling here anyway is that this device > > > *cannot* be used by *any* board, it is not just a board level configuration > > > decision like disabling I2C nodes by default or similar that was proposed > > > last time we had the "nodes disabled by default" discussion. > > > > Hmm.. If that is the case, then why even have it in dts - is that > > because of cases where OPTEE is'nt the TEE and users may want to > > directly use it? OR is it because OPTEE can potentially use device tree > > itself and discover the rng location from dt? > > > > Hadn't thought about the second case, but it could also be valid if we > started using DT in our OPTEE. The intention was for the first case, > this node has valid hardware description, didn't feel right to delete > it due to it being unusable by Linux. Fair enough, it is a bit late for me to let this series cook in list and then apply and wait for linux-next stability before I tag for next kernel, I suggest improving the commit message with rationale in the next rev. -- Regards, Nishanth Menon Key (0xDDB5849D1736249D) / Fingerprint: F8A2 8693 54EB 8232 17A3 1A34 DDB5 849D 1736 249D From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 3CEFDC433EF for ; Fri, 8 Jul 2022 22:10:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:CC:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; 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Fri, 8 Jul 2022 17:09:41 -0500 Received: from localhost (ileax41-snat.itg.ti.com [10.172.224.153]) by lelv0326.itg.ti.com (8.15.2/8.15.2) with ESMTP id 268M9f0v029095; Fri, 8 Jul 2022 17:09:41 -0500 Date: Fri, 8 Jul 2022 17:09:41 -0500 From: Nishanth Menon To: Andrew Davis CC: Bryan Brattlof , Vignesh Raghavendra , Tero Kristo , Rob Herring , Krzysztof Kozlowski , , , Subject: Re: [PATCH v2 1/4] arm64: dts: ti: k3-am65-main: Disable RNG node Message-ID: <20220708220941.skpq7i7ilccw5zdt@secret> References: <20220706190838.26074-1-afd@ti.com> <20220707144400.tk3wmpeijdhuxpzv@bryanbrattlof.com> <20220707171734.e22t5rx5ux7k5kcr@magnetize> <1d6d171f-3c91-530a-27a5-c93153cb2378@ti.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1d6d171f-3c91-530a-27a5-c93153cb2378@ti.com> User-Agent: NeoMutt/20171215 X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220708_150946_532571_FDE3E3BF X-CRM114-Status: GOOD ( 42.78 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 12:36-20220707, Andrew Davis wrote: > On 7/7/22 12:17 PM, Nishanth Menon wrote: > > On 10:01-20220707, Andrew Davis wrote: > > > On 7/7/22 9:44 AM, Bryan Brattlof wrote: > > > > Hi Andrew > > > > > > > > On July 6, 2022 thus sayeth Andrew Davis: > > > > > The hardware random number generator is used by OP-TEE and is access is > > > > > denied to other users with SoC level bus firewalls. Any access to this > > > > > device from Linux will result in firewall errors. Disable this node. > > > > > > > > > > Signed-off-by: Andrew Davis > > > > > --- > > > > > > > > > > Changes from v1: > > > > > - Added comment in dtsi file > > > > > > > > > > arch/arm64/boot/dts/ti/k3-am65-main.dtsi | 1 + > > > > > 1 file changed, 1 insertion(+) > > > > > > > > > > diff --git a/arch/arm64/boot/dts/ti/k3-am65-main.dtsi b/arch/arm64/boot/dts/ti/k3-am65-main.dtsi > > > > > index e749343accedd..9de5a8294acd6 100644 > > > > > --- a/arch/arm64/boot/dts/ti/k3-am65-main.dtsi > > > > > +++ b/arch/arm64/boot/dts/ti/k3-am65-main.dtsi > > > > > @@ -127,6 +127,7 @@ rng: rng@4e10000 { > > > > > reg = <0x0 0x4e10000 0x0 0x7d>; > > > > > interrupts = ; > > > > > clocks = <&k3_clks 136 1>; > > > > > + status = "disabled"; /* Used by OP-TEE */ > > > > > > > > Just curious about how we should document disabling nodes. I was > > > > assuming the reasoning should be described in the bindings? > > > > > > > > I would like to start disabling nodes by default in our dtsi files and > > > > enabling them in our top dts file, making it easier for others to use > > > > our device tree for a more focused purpose than our dev boards. I just > > > > didn't know where I should document why I disabled the nodes :) > > > > > > > > > > This got push-back last time this was suggested, I'll have to lookup > > > the history. IIRC we landed on the other way around, all things should > > > be described by default, then the specific board can enable/disable > > > what is not used as needed. > > > > See thread https://lore.kernel.org/linux-arm-kernel/YiizsYnKB0X9bDY2@atomide.com/ > > > > > > > > I was worried this topic would come up with this patch series and was > > > almost just going to delete the whole RNG node instead of disabling it > > > to avoid that. My reasoning for disabling here anyway is that this device > > > *cannot* be used by *any* board, it is not just a board level configuration > > > decision like disabling I2C nodes by default or similar that was proposed > > > last time we had the "nodes disabled by default" discussion. > > > > Hmm.. If that is the case, then why even have it in dts - is that > > because of cases where OPTEE is'nt the TEE and users may want to > > directly use it? OR is it because OPTEE can potentially use device tree > > itself and discover the rng location from dt? > > > > Hadn't thought about the second case, but it could also be valid if we > started using DT in our OPTEE. The intention was for the first case, > this node has valid hardware description, didn't feel right to delete > it due to it being unusable by Linux. Fair enough, it is a bit late for me to let this series cook in list and then apply and wait for linux-next stability before I tag for next kernel, I suggest improving the commit message with rationale in the next rev. -- Regards, Nishanth Menon Key (0xDDB5849D1736249D) / Fingerprint: F8A2 8693 54EB 8232 17A3 1A34 DDB5 849D 1736 249D _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel