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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A97E0C43603 for ; Mon, 16 Dec 2019 18:25:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7179B2082E for ; Mon, 16 Dec 2019 18:25:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576520749; bh=QBrHzF/bDur2YZKXK3pZ0+nH4CtHkNb06QOzdb7jU/I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=TwBGMMbuvZUh2JE1KOR7ADDXtZR1fnLN/j9Nlsygf9AzQZJGqgY4QEaGpoAkg8hs1 AZiq7wK9MBJ0Qs+BrQ+SYM87Oj+GOd2mkeA9VqeRGuNiFIief1TAbvYd4lVoAdqFCh YCTJ95bGSEEhdjt5iaU2GchCk6OXq0ElnEayDzws= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731892AbfLPSZs (ORCPT ); Mon, 16 Dec 2019 13:25:48 -0500 Received: from mail.kernel.org ([198.145.29.99]:42278 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731496AbfLPSRr (ORCPT ); Mon, 16 Dec 2019 13:17:47 -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 54E5C207FF; Mon, 16 Dec 2019 18:17:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576520266; bh=QBrHzF/bDur2YZKXK3pZ0+nH4CtHkNb06QOzdb7jU/I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Lmom3sP440Gbbom3/8CzNIhDsJnvRBLhePANfqaxSOx3dVQBPek8OB9TcFhMz9Olc OyyVoMUtRkVl+Gru7oNK8nYs0uNY6xtYHS5ExFHJoKEB+BxrrzVhQB2EYnDvWKUXeL Tyu3HTXpw2vmi8jiY4WfUGSxakEIVauPmQb8X0v0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sumit Garg , Herbert Xu Subject: [PATCH 5.4 082/177] hwrng: omap - Fix RNG wait loop timeout Date: Mon, 16 Dec 2019 18:48:58 +0100 Message-Id: <20191216174837.647919779@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20191216174811.158424118@linuxfoundation.org> References: <20191216174811.158424118@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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;