From patchwork Thu Aug 24 19:20:58 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Martin Kaiser X-Patchwork-Id: 13364594 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 BC6CBC71153 for ; Thu, 24 Aug 2023 19:24:47 +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:References:In-Reply-To: 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: List-Owner; bh=JnCaVfZ3R7fihnHonsiLm+bLBpM2yKhSjmQeNH4688A=; b=AQiwrmy/z0Mkr0 zLvwOu+5VkCT9cfF64TE/I2dvZqoB0jb6pw3X6aSl9tOs9j2GJF8BKp3aWbWerO5QprAQ8XPTqUJ1 qi7JuxzSn1TWn7FNZyxS00ZnapfknM2z3IiVciuOXYEcUh/ccfv6Q0erGGjDnrXxL8T3k2HFNI/kc IXt7cyvaH/EAYka8unzL1IHKkOKlSW4AFJ1kL6PeikjLhzhTA8unlBZl5HdPixMTvATyDOy6eGcLZ rXJlasEZE+X6ng7XSDokVbM63wpTeTzqzVtqnfEvQPAAx9RfUCpTGvts7HdwwHjP032Xj0fBmXQe3 R5w3h9QbhJD5VB2fH29A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qZFwC-003ewh-3C; Thu, 24 Aug 2023 19:24:12 +0000 Received: from viti.kaiser.cx ([2a01:238:43fe:e600:cd0c:bd4a:7a3:8e9f]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qZFvt-003eqx-0P for linux-arm-kernel@lists.infradead.org; Thu, 24 Aug 2023 19:23:55 +0000 Received: from dslb-188-097-211-187.188.097.pools.vodafone-ip.de ([188.97.211.187] helo=martin-debian-2.paytec.ch) by viti.kaiser.cx with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1qZFvl-00036P-Io; Thu, 24 Aug 2023 21:23:45 +0200 From: Martin Kaiser To: Herbert Xu Cc: Alexander Stein , linux-crypto@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Martin Kaiser Subject: [PATCH v2 5/6] hwrng: imx-rngc - use polling for initial seed Date: Thu, 24 Aug 2023 21:20:58 +0200 Message-Id: <20230824192059.1569591-6-martin@kaiser.cx> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230824192059.1569591-1-martin@kaiser.cx> References: <20230824192059.1569591-1-martin@kaiser.cx> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230824_122353_319146_F5ABE493 X-CRM114-Status: GOOD ( 16.06 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Use polling instead of interrupt + completion to wait until the initial seed was calculated. This should take about 30ms. Call readl_poll_timeout and set the poll interval to the recommended maximum of 20ms. readl_poll_timeout uses usleep_range, this is based on a hrtimer. The task will we put to sleep while waiting, this does not burn CPU cycles by waiting in the foreground. Signed-off-by: Martin Kaiser --- v2: - use shorter timeout and polling interval - readl_poll_timeout does not wait in the foreground drivers/char/hw_random/imx-rngc.c | 27 +++++++++------------------ 1 file changed, 9 insertions(+), 18 deletions(-) diff --git a/drivers/char/hw_random/imx-rngc.c b/drivers/char/hw_random/imx-rngc.c index c2582673427d..3a3f0f923bed 100644 --- a/drivers/char/hw_random/imx-rngc.c +++ b/drivers/char/hw_random/imx-rngc.c @@ -166,34 +166,29 @@ 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, ctrl; + u32 cmd, ctrl, status, err_reg; int ret; /* clear error */ cmd = readl(rngc->base + RNGC_COMMAND); writel(cmd | RNGC_CMD_CLR_ERR, rngc->base + RNGC_COMMAND); - imx_rngc_irq_unmask(rngc); - /* create seed, repeat while there is some statistical error */ do { /* seed creation */ cmd = readl(rngc->base + RNGC_COMMAND); writel(cmd | RNGC_CMD_SEED, rngc->base + RNGC_COMMAND); - ret = wait_for_completion_timeout(&rngc->rng_op_done, - usecs_to_jiffies(RNGC_SEED_TIMEOUT)); - if (!ret) { - ret = -ETIMEDOUT; - goto err; - } + ret = readl_poll_timeout(rngc->base + RNGC_STATUS, status, + status & RNGC_STATUS_SEED_DONE, 20000, RNGC_SEED_TIMEOUT); + if (ret < 0) + return ret; - } while (rngc->err_reg == RNGC_ERROR_STATUS_STAT_ERR); + err_reg = readl(rngc->base + RNGC_ERROR); + } while (err_reg == RNGC_ERROR_STATUS_STAT_ERR); - if (rngc->err_reg) { - ret = -EIO; - goto err; - } + if (err_reg) + return -EIO; /* * enable automatic seeding, the rngc creates a new seed automatically @@ -209,10 +204,6 @@ static int imx_rngc_init(struct hwrng *rng) * we mask the interrupt ourselves if we return an error */ return 0; - -err: - imx_rngc_irq_mask_clear(rngc); - return ret; } static void imx_rngc_cleanup(struct hwrng *rng)