From patchwork Mon Dec 16 17:48:30 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 181773 Delivered-To: patch@linaro.org Received: by 2002:a92:3001:0:0:0:0:0 with SMTP id x1csp4656904ile; Mon, 16 Dec 2019 10:10:00 -0800 (PST) X-Google-Smtp-Source: APXvYqwGaYs77wOwJ5mS3qs7+nd99v9mq6WKqLdphhqm0C/8hb5xh0MG7QcS9iA4Iv1O73mbApIp X-Received: by 2002:a05:6830:1e5a:: with SMTP id e26mr31456078otj.351.1576519800571; Mon, 16 Dec 2019 10:10:00 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1576519800; cv=none; d=google.com; s=arc-20160816; b=iKpSA7eV2XT8ETElpOkVx0vzhq5iETcKH7yeItxXYa5ng/oZ4wy/RYaG3iEF4lTNnE XFyWa959VTbXpOxAhstFQKivWUxezUlimtnlUzg4d1qrJLqNjpJEtoyuwwJ8BP8UIUE3 7NydQ2ErRCYVw0EdOyWi0U9otqhAjmTS7Vc5hk27brmmbgNVjyq6MpP+VjppMhAcLIvt +U/QlIqB19engySifgSqYgdOaYe2WqS4aNYN6+bXGqiva/RN4JGic87dCB/HLTz5eXmU 0ycoKxlBhYeK46FLVAerMlHKUECmHVtiM9i6iUmylgsSGV54YABwf+IQwKFm6zibjg6g eiAg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :user-agent:references:in-reply-to:message-id:date:subject:cc:to :from:dkim-signature; bh=MZf+Xw64B9aCTBHLkgJQHu3FWLkjCSyCcecHZ6GD+dk=; b=ukz9hGqSwmKoBVFIdT9Ejt7k+KtUSP5dcXxcOnzbEcr4/mYjEeNI4iqNB+JjIIO4uR FQhBrozOiAp9pBPsUEGqlZepxuBw+DRG2ZInyOc6qk/59rUp938CLgIPdLVnZzWZlZzU xfj7cWyjCGjuz0deJdYSjqiRu6tNemTh517WHPfOHwj4VzL6EPYNTmD13o5ZFAEi3L65 iVAuQ4Xmk/5xs8PgVRpbDySfliq1/zFFg2IVQcSp3TkdVBeWdFHmgF15Fi1W3X0Xt1cq /p76IxEbNhIejikCJ+BpI8JbeaFCQwUHv5kRZ+mS0vUDYt1/AKLzRMBKRuOGntXnK4f3 aYvA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=ZhIR+LP0; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id z21si10451472oti.160.2019.12.16.10.10.00; Mon, 16 Dec 2019 10:10:00 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=ZhIR+LP0; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730300AbfLPSJ6 (ORCPT + 27 others); Mon, 16 Dec 2019 13:09:58 -0500 Received: from mail.kernel.org ([198.145.29.99]:52646 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730188AbfLPSJ4 (ORCPT ); Mon, 16 Dec 2019 13:09:56 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B5E5C206B7; Mon, 16 Dec 2019 18:09:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576519796; bh=QBrHzF/bDur2YZKXK3pZ0+nH4CtHkNb06QOzdb7jU/I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZhIR+LP0UYnKwUljIK73GZJgLpq3mk3VJMrALT6w3bZ7NIghxu7kIzcnjq8CxQfa1 H4pNM+UBLC3+is68JiuvK/MxpRK7xALN61FZlp8IjzlxJaUV6e3uUM0UQzcNGnR9ke /NXrioLc/qhdmK10s2uv2CLBIBshsxgHqirRnEZE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sumit Garg , Herbert Xu Subject: [PATCH 5.3 070/180] hwrng: omap - Fix RNG wait loop timeout Date: Mon, 16 Dec 2019 18:48:30 +0100 Message-Id: <20191216174830.209592374@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20191216174806.018988360@linuxfoundation.org> References: <20191216174806.018988360@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sumit Garg commit be867f987a4e1222114dd07a01838a17c26f3fff upstream. Existing RNG data read timeout is 200us but it doesn't cover EIP76 RNG data rate which takes approx. 700us to produce 16 bytes of output data as per testing results. So configure the timeout as 1000us to also take account of lack of udelay()'s reliability. Fixes: 383212425c92 ("hwrng: omap - Add device variant for SafeXcel IP-76 found in Armada 8K") Cc: Signed-off-by: Sumit Garg Signed-off-by: Herbert Xu Signed-off-by: Greg Kroah-Hartman --- drivers/char/hw_random/omap-rng.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) --- a/drivers/char/hw_random/omap-rng.c +++ b/drivers/char/hw_random/omap-rng.c @@ -66,6 +66,13 @@ #define OMAP4_RNG_OUTPUT_SIZE 0x8 #define EIP76_RNG_OUTPUT_SIZE 0x10 +/* + * EIP76 RNG takes approx. 700us to produce 16 bytes of output data + * as per testing results. And to account for the lack of udelay()'s + * reliability, we keep the timeout as 1000us. + */ +#define RNG_DATA_FILL_TIMEOUT 100 + enum { RNG_OUTPUT_0_REG = 0, RNG_OUTPUT_1_REG, @@ -176,7 +183,7 @@ static int omap_rng_do_read(struct hwrng if (max < priv->pdata->data_size) return 0; - for (i = 0; i < 20; i++) { + for (i = 0; i < RNG_DATA_FILL_TIMEOUT; i++) { present = priv->pdata->data_present(priv); if (present || !wait) break;