From patchwork Mon Apr 3 01:19:28 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Golle X-Patchwork-Id: 13197614 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 88F78C7619A for ; Mon, 3 Apr 2023 01:19:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=CTGyR7LCQoy96a9ILhwN+Ycbc1fuDFmtWGjFfBaYhbs=; b=d6akPpEjvi+EP7MLilJF54+eWG VjKQYd3QPH0ZGdSeWSo9GuSSdc6e6l4oyCx4WXjMtQ9tpquf0AJwgcrYMKb7oKnvDY1Ufa34FR1Se D9VvYIUH639Bt32YMtmqREocVpRbVT64mzYnW0A1r+vGAwF7oZd9DgZxitslUvPCULz+/036aKxIk /m+0hIfuF6rgB7naJQSuiID0xajvkwBx9L9b8LuPg+uN4reIjIgcyYA/aKXTqWkWcDlJhKoB3NxhV cKZl7kiLhg2y4o+p7SIF5shDnfYHlRztWhpYm1779byKJgGgQonvLARonEVp8OJxtK23wxq9fcsjQ Oe5DEBWQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1pj8rC-00DiQH-1s; Mon, 03 Apr 2023 01:19:38 +0000 Received: from fudo.makrotopia.org ([2a07:2ec0:3002::71]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1pj8r7-00DiKq-2X; Mon, 03 Apr 2023 01:19:36 +0000 Received: from local by fudo.makrotopia.org with esmtpsa (TLS1.3:TLS_AES_256_GCM_SHA384:256) (Exim 4.96) (envelope-from ) id 1pj8r6-0004nc-1Z; Mon, 03 Apr 2023 03:19:32 +0200 Date: Mon, 3 Apr 2023 02:19:28 +0100 From: Daniel Golle To: netdev@vger.kernel.org, linux-mediatek@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Andrew Lunn , Florian Fainelli , Vladimir Oltean , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Matthias Brugger , AngeloGioacchino Del Regno , Sean Wang , Landen Chao , DENG Qingfang , Philipp Zabel , Russell King , =?utf-8?b?QXLEsW7DpyDDnG5hbA==?= Cc: Sam Shih , Lorenzo Bianconi , John Crispin , Felix Fietkau Subject: [PATCH net-next v2 12/14] net: dsa: mt7530: skip locking if MDIO bus isn't present Message-ID: <82f84ef9850bddf5a855f568594c403270a08249.1680483896.git.daniel@makrotopia.org> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230402_181933_845454_8A3AFDED X-CRM114-Status: GOOD ( 12.30 ) X-BeenThere: linux-mediatek@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-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org As MT7530 and MT7531 internally use 32-bit wide registers, each access to any register of the switch requires several operations on the MDIO bus. Hence if there is congruent access, e.g. due to PCS or PHY polling, this can mess up and interfere with another ongoing register access sequence. However, the MDIO bus mutex is only relevant for MDIO-connected switches. Prepare switches which have there registers directly mapped into the SoCs register space via MMIO which do not require such locking. There we can simply use regmap's default locking mechanism. Hence guard mutex operations to only be performed in case of MDIO connected switches. Signed-off-by: Daniel Golle Reviewed-by: Andrew Lunn --- drivers/net/dsa/mt7530.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c index ac485ee83ed07..394fada7ddf13 100644 --- a/drivers/net/dsa/mt7530.c +++ b/drivers/net/dsa/mt7530.c @@ -144,13 +144,15 @@ core_write_mmd_indirect(struct mt7530_priv *priv, int prtad, static void mt7530_mutex_lock(struct mt7530_priv *priv) { - mutex_lock_nested(&priv->bus->mdio_lock, MDIO_MUTEX_NESTED); + if (priv->bus) + mutex_lock_nested(&priv->bus->mdio_lock, MDIO_MUTEX_NESTED); } static void mt7530_mutex_unlock(struct mt7530_priv *priv) { - mutex_unlock(&priv->bus->mdio_lock); + if (priv->bus) + mutex_unlock(&priv->bus->mdio_lock); } static void