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 20C14C54EBC for ; Mon, 9 Jan 2023 02:58:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233145AbjAIC60 convert rfc822-to-8bit (ORCPT ); Sun, 8 Jan 2023 21:58:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58476 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231225AbjAIC6Z (ORCPT ); Sun, 8 Jan 2023 21:58:25 -0500 Received: from fd01.gateway.ufhost.com (fd01.gateway.ufhost.com [61.152.239.71]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E3C471114F; Sun, 8 Jan 2023 18:58:22 -0800 (PST) Received: from EXMBX165.cuchost.com (unknown [175.102.18.54]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "EXMBX165", Issuer "EXMBX165" (not verified)) by fd01.gateway.ufhost.com (Postfix) with ESMTP id AD34324E161; Mon, 9 Jan 2023 10:58:14 +0800 (CST) Received: from EXMBX064.cuchost.com (172.16.6.64) by EXMBX165.cuchost.com (172.16.6.75) with Microsoft SMTP Server (TLS) id 15.0.1497.42; Mon, 9 Jan 2023 10:58:14 +0800 Received: from EXMBX168.cuchost.com (172.16.6.78) by EXMBX064.cuchost.com (172.16.6.64) with Microsoft SMTP Server (TLS) id 15.0.1497.42; Mon, 9 Jan 2023 10:58:14 +0800 Received: from EXMBX168.cuchost.com ([fe80::3c2d:dee5:4938:3fc4]) by EXMBX168.cuchost.com ([fe80::3c2d:dee5:4938:3fc4%16]) with mapi id 15.00.1497.044; Mon, 9 Jan 2023 10:58:14 +0800 From: JiaJie Ho To: Herbert Xu CC: Olivia Mackall , Rob Herring , Krzysztof Kozlowski , Emil Renner Berthing , Conor Dooley , "linux-crypto@vger.kernel.org" , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-riscv@lists.infradead.org" Subject: RE: [PATCH v2 2/3] hwrng: starfive - Add TRNG driver for StarFive SoC Thread-Topic: [PATCH v2 2/3] hwrng: starfive - Add TRNG driver for StarFive SoC Thread-Index: AQHZGoveBWEVWeSp5UqGtlmGFQKs8K6QmY4AgATZceA= Date: Mon, 9 Jan 2023 02:58:14 +0000 Message-ID: <7c2cc6e9cdf241318fc73162a5ec221d@EXMBX168.cuchost.com> References: <20221228071103.91797-1-jiajie.ho@starfivetech.com> <20221228071103.91797-3-jiajie.ho@starfivetech.com> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [202.190.108.220] x-yovoleruleagent: yovoleflag Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org > -----Original Message----- > From: Herbert Xu > Sent: 6 January, 2023 4:39 PM > To: JiaJie Ho > Cc: Olivia Mackall ; Rob Herring ; > Krzysztof Kozlowski ; Emil Renner > Berthing ; Conor Dooley ; > linux-crypto@vger.kernel.org; devicetree@vger.kernel.org; linux- > kernel@vger.kernel.org; linux-riscv@lists.infradead.org > Subject: Re: [PATCH v2 2/3] hwrng: starfive - Add TRNG driver for StarFive > SoC > > On Wed, Dec 28, 2022 at 03:11:02PM +0800, Jia Jie Ho wrote: > > +static int starfive_trng_read(struct hwrng *rng, void *buf, size_t > > +max, bool wait) > > You should respect the wait argument and not do polling/sleeping if it is false. > Hi Herbert, My trng device requires sending a generate new number cmd before each read. It then only populates the data registers with new random number and raise an interrupt when ready. If user choose to not wait, they will always get stale bits. Is it okay to always return error if wait=false ? Thanks Jia Jie