From patchwork Fri May 31 08:53:22 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Marek Vasut X-Patchwork-Id: 13681323 X-Patchwork-Delegate: herbert@gondor.apana.org.au Received: from phobos.denx.de (phobos.denx.de [85.214.62.61]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A3B23155A53 for ; Fri, 31 May 2024 08:54:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=85.214.62.61 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717145693; cv=none; b=W82n76BTrmFpg9kSsBJgsZl2taX/EdOhkqtxrME4k8xrHAnLJTIk410+uKILriZB9873hQM+D7w2OnzAz1vzwQplvbzIXpkJjNnWLYE6xFgbUFzJvsq/+pIFEd2U2M+7y53xba8z4uwKq8+kZHaLH+FLuKQcQ4TvLYAAq2oDlWo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717145693; c=relaxed/simple; bh=QdZESmhfftlpEVQahcIpjh8FCP+VbYIkQ0nBIND/vjQ=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=S3i4Sri3juSTBB4wO+daK3zgdzGL6R5o4N1suMI81n2+FU90GWnCuIubH/hxK3RTCzoXGGRfVFRgQ82rNijwoNni2HKIKI1Cj1ViwrROZeBVN4HRJleTyYJg+diFSbfGQm7tlZm6yN3LDSGk0ezXS4pqQbWj53A6dfhfJ9ywwUs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=denx.de; spf=pass smtp.mailfrom=denx.de; dkim=pass (2048-bit key) header.d=denx.de header.i=@denx.de header.b=puqYrpH/; arc=none smtp.client-ip=85.214.62.61 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=denx.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=denx.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=denx.de header.i=@denx.de header.b="puqYrpH/" Received: from tr.lan (ip-86-49-120-218.bb.vodafone.cz [86.49.120.218]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: marex@denx.de) by phobos.denx.de (Postfix) with ESMTPSA id 0854088246; Fri, 31 May 2024 10:54:42 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=denx.de; s=phobos-20191101; t=1717145684; bh=ywmgWnjL30EYt/MuxhcwoOkfzGrfhbBZytmaTjE4Urk=; h=From:To:Cc:Subject:Date:From; b=puqYrpH/xjOIMgIMVamSDiZta2T3W48g2YC3oYqo/lcXAHkyOYsW1hOvZ44AZYXUa ubDkL58J1in5SR8mo3W+oc0QDdMc3WiBR1ArQqUTZ4RblKrjThPVZxZSml/RmFFk3S tMDtP4vtRtlu1K6ZnD/zmDMzQlxiIvFpwzbnNevQaEgxmvJofiwjEHWqDRprUs7kSQ nrgDHGiBLo5qWtxWfbGav8HboIT3QcR70+qCQeS+dXpVoObx+S/sMo293Mk5c+ao/1 SpViP2OMIhngjNPvu4lfVDi/hhoF2ZiIU3i7zhY4ggKh1ZaFsXGgRmdhWJxcMVlvTB MvkzgZc/sFYsA== From: Marek Vasut To: linux-crypto@vger.kernel.org Cc: Marek Vasut , Gatien Chevallier , =?utf-8?q?Uwe_Kleine-K?= =?utf-8?q?=C3=B6nig?= , Alexandre Torgue , Herbert Xu , Maxime Coquelin , Olivia Mackall , Rob Herring , Yang Yingliang , kernel@dh-electronics.com, linux-arm-kernel@lists.infradead.org, linux-stm32@st-md-mailman.stormreply.com Subject: [PATCH v3 1/2] hwrng: stm32 - use pm_runtime_resume_and_get() Date: Fri, 31 May 2024 10:53:22 +0200 Message-ID: <20240531085414.42529-1-marex@denx.de> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-crypto@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Virus-Scanned: clamav-milter 0.103.8 at phobos.denx.de X-Virus-Status: Clean include/linux/pm_runtime.h pm_runtime_get_sync() description suggests to ... consider using pm_runtime_resume_and_get() instead of it, especially if its return value is checked by the caller, as this is likely to result in cleaner code. This is indeed better, switch to pm_runtime_resume_and_get() which correctly suspends the device again in case of failure. Also add error checking into the RNG driver in case pm_runtime_resume_and_get() does fail, which is currently not done, and it does detect sporadic -EACCES error return after resume, which would otherwise lead to a hang due to register access on un-resumed hardware. Now the read simply errors out and the system does not hang. Acked-by: Gatien Chevallier Signed-off-by: Marek Vasut --- Cc: "Uwe Kleine-König" Cc: Alexandre Torgue Cc: Gatien Chevallier Cc: Herbert Xu Cc: Marek Vasut Cc: Maxime Coquelin Cc: Olivia Mackall Cc: Rob Herring Cc: Yang Yingliang Cc: kernel@dh-electronics.com Cc: linux-arm-kernel@lists.infradead.org Cc: linux-crypto@vger.kernel.org Cc: linux-stm32@st-md-mailman.stormreply.com --- V2: Add AB from Gatien V3: No change --- drivers/char/hw_random/stm32-rng.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/char/hw_random/stm32-rng.c b/drivers/char/hw_random/stm32-rng.c index 0e903d6e22e30..6dec4adc49853 100644 --- a/drivers/char/hw_random/stm32-rng.c +++ b/drivers/char/hw_random/stm32-rng.c @@ -187,7 +187,9 @@ static int stm32_rng_read(struct hwrng *rng, void *data, size_t max, bool wait) int retval = 0, err = 0; u32 sr; - pm_runtime_get_sync((struct device *) priv->rng.priv); + retval = pm_runtime_resume_and_get((struct device *)priv->rng.priv); + if (retval) + return retval; if (readl_relaxed(priv->base + RNG_SR) & RNG_SR_SEIS) stm32_rng_conceal_seed_error(rng);