From patchwork Thu Mar 5 20:58:21 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Martin Kaiser X-Patchwork-Id: 11422641 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6408A924 for ; Thu, 5 Mar 2020 21:00:36 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 31D9F20801 for ; Thu, 5 Mar 2020 21:00:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="d8z8WE/J" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 31D9F20801 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kaiser.cx Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=UkHJ3VrNNbgOq9BT3+axlllABArq/FvFePD7EWYfNPs=; b=d8z8WE/J3Ose5Z jnrDp1Hg68stYwaX42YmNCFYjUAWDS+7yuUP3v4zuMXaN0mXuWR8HKTfafhpWzxACY/AZdwIcyuIz QALvoEo0RmU9joe0XaXl2KPBgDrED83g6UZUwtVHVakGcFwrvdYvUwK5yUiR5A1bcfSQMjwplFLm7 OHxenShGs6nsrArjBc2bII7tOBgclczC2C/zgrsGr8A333Q+sP0+EuwgdRCLGZDBhzRd6NRWYvMXe R9SsN2uFnFmpKgRO+lcdK9zYG13L8CPU2eFIdbFxdEcRTr3/ewFVSydVb72Lyz2KPQ0HltIdQJIk2 l6OZc0yRNuBdVhBT4H3A==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1j9xbe-0003qk-PJ; Thu, 05 Mar 2020 21:00:34 +0000 Received: from viti.kaiser.cx ([2a01:238:43fe:e600:cd0c:bd4a:7a3:8e9f]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1j9xad-0001gi-Fi for linux-arm-kernel@lists.infradead.org; Thu, 05 Mar 2020 20:59:34 +0000 Received: from 250.57.4.146.static.wline.lns.sme.cust.swisscom.ch ([146.4.57.250] helo=martin-debian-2.paytec.ch) by viti.kaiser.cx with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.89) (envelope-from ) id 1j9xaU-0000e9-QU; Thu, 05 Mar 2020 21:59:22 +0100 From: Martin Kaiser To: Herbert Xu , PrasannaKumar Muralidharan , NXP Linux Team Subject: [PATCH v2 2/5] hwrng: imx-rngc - use automatic seeding Date: Thu, 5 Mar 2020 21:58:21 +0100 Message-Id: <20200305205824.4371-3-martin@kaiser.cx> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200305205824.4371-1-martin@kaiser.cx> References: <20200128110102.11522-1-martin@kaiser.cx> <20200305205824.4371-1-martin@kaiser.cx> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200305_125931_673871_A5BEBA66 X-CRM114-Status: GOOD ( 12.28 ) X-Spam-Score: 0.0 (/) X-Spam-Report: SpamAssassin version 3.4.3 on bombadil.infradead.org summary: Content analysis details: (0.0 points) pts rule name description ---- ---------------------- -------------------------------------------------- 0.0 SPF_NONE SPF: sender does not publish an SPF Record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Martin Kaiser , linux-crypto@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org The rngc requires a new seed for its prng after generating 2^20 160-bit words of random data. At the moment, we seed the prng only once during initalisation. Set the rngc to auto seed mode so that it kicks off the internal reseeding operation when a new seed is required. Keep the manual calculation of the initial seed when the device is probed and switch to automatic seeding afterwards. Reviewed-by: PrasannaKumar Muralidharan Signed-off-by: Martin Kaiser --- drivers/char/hw_random/imx-rngc.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/drivers/char/hw_random/imx-rngc.c b/drivers/char/hw_random/imx-rngc.c index 0576801944fd..903894518c8d 100644 --- a/drivers/char/hw_random/imx-rngc.c +++ b/drivers/char/hw_random/imx-rngc.c @@ -31,6 +31,7 @@ #define RNGC_CTRL_MASK_ERROR 0x00000040 #define RNGC_CTRL_MASK_DONE 0x00000020 +#define RNGC_CTRL_AUTO_SEED 0x00000010 #define RNGC_STATUS_ERROR 0x00010000 #define RNGC_STATUS_FIFO_LEVEL_MASK 0x00000f00 @@ -167,7 +168,7 @@ static irqreturn_t imx_rngc_irq(int irq, void *priv) static int imx_rngc_init(struct hwrng *rng) { struct imx_rngc *rngc = container_of(rng, struct imx_rngc, rng); - u32 cmd; + u32 cmd, ctrl; int ret; /* clear error */ @@ -192,7 +193,18 @@ static int imx_rngc_init(struct hwrng *rng) } while (rngc->err_reg == RNGC_ERROR_STATUS_STAT_ERR); - return rngc->err_reg ? -EIO : 0; + if (rngc->err_reg) + return -EIO; + + /* + * enable automatic seeding, the rngc creates a new seed automatically + * after serving 2^20 random 160-bit words + */ + ctrl = readl(rngc->base + RNGC_CONTROL); + ctrl |= RNGC_CTRL_AUTO_SEED; + writel(ctrl, rngc->base + RNGC_CONTROL); + + return 0; } static int imx_rngc_probe(struct platform_device *pdev)