From patchwork Mon Dec 2 14:44:06 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dragan Simic X-Patchwork-Id: 13890849 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 611E6D78326 for ; Mon, 2 Dec 2024 14:46:35 +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:MIME-Version:Message-Id:Date:Subject:Cc :To:From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=5tLGcXddyPLTJ8MhtKQJo/dqAhP1P6MZHwP42N+6Vs4=; b=1Z/+b27RiUlcxu Q4i6abEwTiHTtcNQkaH6qHxNSnF6x4U+4LiiceZOxznlKG/+oSe0X2ehCt3dUO/GlgVPhoIYeMRFi vxQfoirJu74uOO2k7gHRYm+K/e/qKjISa3l2SUmn9YLK8q2coIxVNgqCw8eE5ub55RwbFEioL15pC KscNQAamVGE/YYFooBTA8Q90iNwxVHiJcxJCjZHIVqTffi1XSS6BQN1GNIB4MNIxrl2u9SSUUyqVk QJF3z6ctTXqIl7GjkzlD1xZUVbNawZmmGJ2eVbQZSRY/9Ie3jg9+eueGW3jR7LHwOMceW+PuloNdi msSq53oJpRcvpgSuhF2Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tI7h1-00000006Vsy-3qx9; Mon, 02 Dec 2024 14:46:31 +0000 Received: from mail.manjaro.org ([2a01:4f8:c0c:51f3::1]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tI7es-00000006VKg-00CA; Mon, 02 Dec 2024 14:44:19 +0000 From: Dragan Simic DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=manjaro.org; s=2021; t=1733150655; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=yRJZlOcms6c9rbeZYvsX5MTDNXpRGMuOjccJ3gJk83o=; b=PUkoZ0sICV8QIm+TzgZgwT/vqL+UjIf3NGBGb4D6j6pG4v29Wgv3b4n0uv1BsxglBCNmIH uODreYlZFOZvBu6Bla55ay6k7a88JO2vegl7w/C1uKNt6atCe4rGTesKRxdMw1lf3ErBdZ SwZY/UPtaJtvmqUt0kSNhPAXX+KO5XvfrbS2EyKPYjw4IOKqcOtGR8FRvKqNT/X9F45v9z pCf63WuI1kut/xi52Pq4ZAZ/L8upFLkVLyChu8t/Es9LeaBkIPoioS66Z/PzSHaGNuSBbd UHXh4KwW+ec1Yq/jgzU8Pfrs1HSxEykI6tlI7PtH2l4+kKPJo3e497eV4UfaWQ== To: linux-rockchip@lists.infradead.org Cc: heiko@sntech.de, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, didi.debian@cknow.org, marcin.juszkiewicz@linaro.org Subject: [PATCH] arm64: dts: rockchip: Describe why is HWRNG disabled in RK356x base dtsi Date: Mon, 2 Dec 2024 15:44:06 +0100 Message-Id: <6b272e2f8f916c04b05db50df621659a5a7f29ab.1733149874.git.dsimic@manjaro.org> MIME-Version: 1.0 Authentication-Results: ORIGINATING; auth=pass smtp.auth=dsimic@manjaro.org smtp.mailfrom=dsimic@manjaro.org X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241202_064418_188776_CF84E397 X-CRM114-Status: UNSURE ( 9.35 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-rockchip@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Upstream kernel work for Rockchip platforms List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-rockchip" Errors-To: linux-rockchip-bounces+linux-rockchip=archiver.kernel.org@lists.infradead.org Despite the presence of the hardware random number generator (HWRNG) in the different Rockchip RK356x SoC variants, it remains disabled for the RK3566 SoC because testing showed [1] that it produces unacceptably low quality of random data, for some yet unknown reason. The HWRNG is enabled for the RK3568 SoC, on which the testing showed good quality of the generated random data. To avoid possible confusion in the future, [2] let's have this described briefly in the RK356x base SoC dtsi. [1] https://lore.kernel.org/linux-rockchip/cover.1720969799.git.daniel@makrotopia.org/T/#u [2] https://lore.kernel.org/linux-rockchip/20241201234613.52322-1-pbrobinson@gmail.com/T/#u Signed-off-by: Dragan Simic Reviewed-by: Diederik de Haas --- arch/arm64/boot/dts/rockchip/rk356x-base.dtsi | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/arm64/boot/dts/rockchip/rk356x-base.dtsi b/arch/arm64/boot/dts/rockchip/rk356x-base.dtsi index 62be06f3b863..ab8f42c0a843 100644 --- a/arch/arm64/boot/dts/rockchip/rk356x-base.dtsi +++ b/arch/arm64/boot/dts/rockchip/rk356x-base.dtsi @@ -1032,6 +1032,11 @@ sdhci: mmc@fe310000 { status = "disabled"; }; + /* + * Testing showed that the HWRNG found in RK3566 produces unacceptably + * low quality of random data, so the HWRNG isn't enabled for all RK356x + * SoC variants despite its presence. + */ rng: rng@fe388000 { compatible = "rockchip,rk3568-rng"; reg = <0x0 0xfe388000 0x0 0x4000>;