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a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=7Xv8o+WsUdwWC7CiaXpsHd5QUxK044+HKFw9W9npptk=; b=XoMkMMEURfokYaYMk4dXBORHt+AEd45+8L7hUy14PpL1pNANA7qclD8fRzdysZnnEO xFlN5QtSD+mmQYIE0KS0xZRKkgr81G7FNxuPlrF/iHM3NP+Ecd5TP46i8R/06QKqUKtL fOrcFVxJsX8kVkZPKtAOzQyShTsoZLZTnd9V9/H5Ye31o9rBEntWTmVjxzpP2EtODpBZ +UCKrhasaS8hhDKvC/EDtjI+49wLgqMRhjNwoZMSgziZsLi9LCZNAlcaVcW2ZGtsgmRe Zn+0ZXy37eqYwSfWOU3b6BmXYcXqM/B1mFlL9gnAddeYVThghxrqfVmk4VpPShsImAbI MabA== X-Gm-Message-State: APjAAAWeSj9LG/zGSMYLSaWwU1F4sdBZiOAL4ysmHfXTfzE8A9EV6QXo RFQHfi4zDvDxQodKMKSAp6RCcrK2oLdTVrt9kOsElg== X-Google-Smtp-Source: APXvYqxqte31rdFQPjtRI2d0z8l6rqekmUjNbkTYkhGQNfoYXbCoNDt/WGK3fQmslUDfdpQIN0cF13ot7mHRN/DXrE0= X-Received: by 2002:a5d:5345:: with SMTP id t5mr34600649wrv.0.1575303135165; Mon, 02 Dec 2019 08:12:15 -0800 (PST) MIME-Version: 1.0 References: <1574864578-467-1-git-send-email-neal.liu@mediatek.com> <1574864578-467-4-git-send-email-neal.liu@mediatek.com> <1575027046.24848.4.camel@mtkswgap22> In-Reply-To: <1575027046.24848.4.camel@mtkswgap22> From: Ard Biesheuvel Date: Mon, 2 Dec 2019 16:12:09 +0000 Message-ID: Subject: Re: [PATCH v5 3/3] hwrng: add mtk-sec-rng driver To: Neal Liu , Catalin Marinas , Will Deacon , Marc Zyngier X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191202_081217_079134_D6FE13CD X-CRM114-Status: GOOD ( 16.37 ) X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , DTML , Herbert Xu , wsd_upstream , Sean Wang , Linux Kernel Mailing List , Rob Herring , =?UTF-8?B?Q3J5c3RhbCBHdW8gKOmDreaZtik=?= , "linux-crypto@vger.kernel.org" , Matt Mackall , Matthias Brugger , "linux-mediatek@lists.infradead.org" , Lars Persson , "linux-arm-kernel@lists.infradead.org" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org (adding some more arm64 folks) On Fri, 29 Nov 2019 at 11:30, Neal Liu wrote: > > On Fri, 2019-11-29 at 18:02 +0800, Lars Persson wrote: > > Hi Neal, > > > > On Wed, Nov 27, 2019 at 3:23 PM Neal Liu wrote: > > > > > > For MediaTek SoCs on ARMv8 with TrustZone enabled, peripherals like > > > entropy sources is not accessible from normal world (linux) and > > > rather accessible from secure world (ATF/TEE) only. This driver aims > > > to provide a generic interface to ATF rng service. > > > > > > > I am working on several SoCs that also will need this kind of driver > > to get entropy from Arm trusted firmware. > > If you intend to make this a generic interface, please clean up the > > references to MediaTek and give it a more generic name. For example > > "Arm Trusted Firmware random number driver". > > > > It will also be helpful if the SMC call number is configurable. > > > > - Lars > > Yes, I'm trying to make this to a generic interface. I'll try to make > HW/platform related dependency to be configurable and let it more > generic. > Thanks for your suggestion. > I don't think it makes sense for each arm64 platform to expose an entropy source via SMC calls in a slightly different way, and model it as a h/w driver. Instead, we should try to standardize this, and perhaps expose it via the architectural helpers that already exist (get_random_seed_long() and friends), so they get plugged into the kernel random pool driver directly. Note that in addition to drivers based on vendor SMC calls, we already have a RNG h/w driver based on OP-TEE as well, where the driver attaches to a standardized trusted OS interface identified by a UUID, and which also gets invoked via SMC calls into secure firmware. _______________________________________________ Linux-mediatek mailing list Linux-mediatek@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-mediatek