From patchwork Mon Oct 24 08:03:28 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wenyou Yang X-Patchwork-Id: 9391567 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 20C7A60231 for ; Mon, 24 Oct 2016 08:08:53 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 116BB28C2B for ; Mon, 24 Oct 2016 08:08:53 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 0390228C2D; Mon, 24 Oct 2016 08:08:53 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=unavailable version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 99F5128C2B for ; Mon, 24 Oct 2016 08:08:52 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1byaI6-0006Ll-UE; Mon, 24 Oct 2016 08:07:30 +0000 Received: from eusmtp01.atmel.com ([212.144.249.242]) by bombadil.infradead.org with esmtps (Exim 4.85_2 #1 (Red Hat Linux)) id 1byaI0-0006I7-Q1 for linux-arm-kernel@lists.infradead.org; Mon, 24 Oct 2016 08:07:28 +0000 Received: from apsmtp01.atmel.com (10.168.254.31) by eusmtp01.atmel.com (10.145.145.30) with Microsoft SMTP Server id 14.3.235.1; Mon, 24 Oct 2016 10:07:02 +0200 Received: from shaarm01.corp.atmel.com (10.168.254.13) by apsmtp01.atmel.com (10.168.254.31) with Microsoft SMTP Server id 14.3.235.1; Mon, 24 Oct 2016 16:08:15 +0800 From: Wenyou Yang To: Herbert Xu , Matt Mackall Subject: [PATCH v1] char: hw_random: atmel-rng: disable TRNG during suspend Date: Mon, 24 Oct 2016 16:03:28 +0800 Message-ID: <1477296208-28335-1-git-send-email-wenyou.yang@atmel.com> X-Mailer: git-send-email 2.7.4 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20161024_010725_203373_5739392F X-CRM114-Status: UNSURE ( 9.40 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arm-kernel@lists.infradead.org, Nicolas Ferre , linux-crypto@vger.kernel.org, Wenyou Yang , Wenyou Yang Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP To fix the over consumption on the VDDCore due to the TRNG enabled, disable the TRNG during suspend, not only disable the user interface clock (which is controlled by PMC). Because the user interface clock is independent from any clock that may be used in the entropy source logic circuitry. Signed-off-by: Wenyou Yang --- drivers/char/hw_random/atmel-rng.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/drivers/char/hw_random/atmel-rng.c b/drivers/char/hw_random/atmel-rng.c index 0fcc9e6..2e2d09a 100644 --- a/drivers/char/hw_random/atmel-rng.c +++ b/drivers/char/hw_random/atmel-rng.c @@ -48,6 +48,16 @@ static int atmel_trng_read(struct hwrng *rng, void *buf, size_t max, return 0; } +static void atmel_trng_enable(struct atmel_trng *trng) +{ + writel(TRNG_KEY | 1, trng->base + TRNG_CR); +} + +static void atmel_trng_disable(struct atmel_trng *trng) +{ + writel(TRNG_KEY, trng->base + TRNG_CR); +} + static int atmel_trng_probe(struct platform_device *pdev) { struct atmel_trng *trng; @@ -71,7 +81,7 @@ static int atmel_trng_probe(struct platform_device *pdev) if (ret) return ret; - writel(TRNG_KEY | 1, trng->base + TRNG_CR); + atmel_trng_enable(trng); trng->rng.name = pdev->name; trng->rng.read = atmel_trng_read; @@ -94,7 +104,7 @@ static int atmel_trng_remove(struct platform_device *pdev) hwrng_unregister(&trng->rng); - writel(TRNG_KEY, trng->base + TRNG_CR); + atmel_trng_disable(trng); clk_disable_unprepare(trng->clk); return 0; @@ -105,6 +115,7 @@ static int atmel_trng_suspend(struct device *dev) { struct atmel_trng *trng = dev_get_drvdata(dev); + atmel_trng_disable(trng); clk_disable_unprepare(trng->clk); return 0; @@ -114,6 +125,7 @@ static int atmel_trng_resume(struct device *dev) { struct atmel_trng *trng = dev_get_drvdata(dev); + atmel_trng_enable(trng); return clk_prepare_enable(trng->clk); }