From patchwork Fri Jun 16 08:58:12 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Martin Kaiser X-Patchwork-Id: 13282337 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 34D4AEB64DA for ; Fri, 16 Jun 2023 09:00:17 +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=zGTDnSwqcl6eOiYMQaYTQMrQcLmMrE5A/kkvc7qTOVU=; b=sOXT1ewF+BpqLT DDL2gv50fgnV3gSGvXaZbGwOhOHrnvl3UYMqdbGrfPvnUuq4GNpIq9/IrsTYoTSJ5JkNE3aFEN0NP bH3nOITHkg9swRunCUG0kGjSKYZMDPsg1bsd7T9FTWwrKrn+TxEA9reI7t0LPp8E/PQiG3j0CFmoB Ed/EC1AHNKMxPetwn6uwW6JJIGHUNJbMZlPc2xIDq6ZRLcGwgK9jO3BGH2EQI5ga9bqOgagBCKm7h 5MCFjH3YKRSXMXjdU0LDoedt5htg+tEkgHhqcO1kj/wjnkm77no4UHwk2TN0qJZyegV3SrdDQGpxY GdRynPaF3HFNvgm1R9Fw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qA5JC-00HODe-1i; Fri, 16 Jun 2023 08:59:54 +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 1qA5Iy-00HO6u-1l for linux-arm-kernel@lists.infradead.org; Fri, 16 Jun 2023 08:59:42 +0000 Received: from [167.98.155.120] (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 1qA5Iv-0000d1-Bl; Fri, 16 Jun 2023 10:59:37 +0200 From: Martin Kaiser To: Herbert Xu Cc: linux-crypto@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Martin Kaiser Subject: [PATCH v2 1/2] hwrng: st - support compile-testing Date: Fri, 16 Jun 2023 09:58:12 +0100 Message-Id: <20230616085813.1323082-2-martin@kaiser.cx> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20230616085813.1323082-1-martin@kaiser.cx> References: <20230616083618.1320824-1-martin@kaiser.cx> <20230616085813.1323082-1-martin@kaiser.cx> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230616_015940_900584_7389B76C X-CRM114-Status: GOOD ( 11.02 ) 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 Allow compile-testing the st-rng driver if we're not running on an ST chipset. Signed-off-by: Martin Kaiser --- drivers/char/hw_random/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig index baefa2e0edbc..e0b3786ca51b 100644 --- a/drivers/char/hw_random/Kconfig +++ b/drivers/char/hw_random/Kconfig @@ -348,7 +348,7 @@ config HW_RANDOM_HISTB config HW_RANDOM_ST tristate "ST Microelectronics HW Random Number Generator support" - depends on HW_RANDOM && ARCH_STI + depends on HW_RANDOM && (ARCH_STI || COMPILE_TEST) help This driver provides kernel-side support for the Random Number Generator hardware found on STi series of SoCs. From patchwork Fri Jun 16 08:58:13 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Martin Kaiser X-Patchwork-Id: 13282336 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 6E105EB64D7 for ; Fri, 16 Jun 2023 09:00:15 +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=VtnOnDlnHo73m7YlJT4Mk76hLjRPbjNQSp2ZYVe2X2A=; b=EBYPm4gZVpg8l7 AEx9xmDnuODrgAwCsOwvN+XFlrpMge0UgoiELuCfCVD9OaktSz2jrkjSI22/WM4RqDxftTeD+IlGb tkjafaYyo8a8Pk5QQDeVx0F7VJAE5Lg4uDlEloZT3U80AcwjMNzDh0ojs+VRdzyXaxuRnkC4HAZoR pU+npjc6oX9gtSsD94ys2Ln8kUxTEVZ/tMKLB7uxv+OAIkSc6jWLDmqpSSiaAEQIMt8MOvFeh7Tx1 fjKMOicHZa8q1f7QJ/SCu3qcWmZBP7G6B3sxa5hTWYm7HD536KdrqMNj9aUyoDfYbghN6/VWwuL9C c834ktXqmm9auNdysnJw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qA5JC-00HOE1-3A; Fri, 16 Jun 2023 08:59:54 +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 1qA5Iz-00HO7T-1s for linux-arm-kernel@lists.infradead.org; Fri, 16 Jun 2023 08:59:43 +0000 Received: from [167.98.155.120] (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 1qA5Iw-0000d1-Op; Fri, 16 Jun 2023 10:59:38 +0200 From: Martin Kaiser To: Herbert Xu Cc: linux-crypto@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Martin Kaiser Subject: [PATCH v2 2/2] hwrng: st - keep clock enabled while hwrng is registered Date: Fri, 16 Jun 2023 09:58:13 +0100 Message-Id: <20230616085813.1323082-3-martin@kaiser.cx> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20230616085813.1323082-1-martin@kaiser.cx> References: <20230616083618.1320824-1-martin@kaiser.cx> <20230616085813.1323082-1-martin@kaiser.cx> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230616_015941_774351_AAC3F429 X-CRM114-Status: GOOD ( 17.69 ) 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 The st-rng driver uses devres to register itself with the hwrng core, the driver will be unregistered from hwrng when its device goes out of scope. This happens after the driver's remove function is called. However, st-rng's clock is disabled in the remove function. There's a short timeframe where st-rng is still registered with the hwrng core although its clock is disabled. I suppose the clock must be active to access the hardware and serve requests from the hwrng core. Switch to devm_clk_get_enabled and let devres disable the clock and unregister the hwrng. This avoids the race condition. Fixes: 3e75241be808 ("hwrng: drivers - Use device-managed registration API") Signed-off-by: Martin Kaiser --- v2: - don't unprepare the clock if devm_hwrng_register fails - don't set driver data, it was used only in the remove function that's now gone - rephrase the commit message, the clock is now disabled by devres drivers/char/hw_random/st-rng.c | 21 +-------------------- 1 file changed, 1 insertion(+), 20 deletions(-) diff --git a/drivers/char/hw_random/st-rng.c b/drivers/char/hw_random/st-rng.c index 15ba1e6fae4d..6e9dfac9fc9f 100644 --- a/drivers/char/hw_random/st-rng.c +++ b/drivers/char/hw_random/st-rng.c @@ -42,7 +42,6 @@ struct st_rng_data { void __iomem *base; - struct clk *clk; struct hwrng ops; }; @@ -85,26 +84,18 @@ static int st_rng_probe(struct platform_device *pdev) if (IS_ERR(base)) return PTR_ERR(base); - clk = devm_clk_get(&pdev->dev, NULL); + clk = devm_clk_get_enabled(&pdev->dev, NULL); if (IS_ERR(clk)) return PTR_ERR(clk); - ret = clk_prepare_enable(clk); - if (ret) - return ret; - ddata->ops.priv = (unsigned long)ddata; ddata->ops.read = st_rng_read; ddata->ops.name = pdev->name; ddata->base = base; - ddata->clk = clk; - - dev_set_drvdata(&pdev->dev, ddata); ret = devm_hwrng_register(&pdev->dev, &ddata->ops); if (ret) { dev_err(&pdev->dev, "Failed to register HW RNG\n"); - clk_disable_unprepare(clk); return ret; } @@ -113,15 +104,6 @@ static int st_rng_probe(struct platform_device *pdev) return 0; } -static int st_rng_remove(struct platform_device *pdev) -{ - struct st_rng_data *ddata = dev_get_drvdata(&pdev->dev); - - clk_disable_unprepare(ddata->clk); - - return 0; -} - static const struct of_device_id st_rng_match[] __maybe_unused = { { .compatible = "st,rng" }, {}, @@ -134,7 +116,6 @@ static struct platform_driver st_rng_driver = { .of_match_table = of_match_ptr(st_rng_match), }, .probe = st_rng_probe, - .remove = st_rng_remove }; module_platform_driver(st_rng_driver);