From nobody Sat Sep 21 02:41:47 2024 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1C89CC77B60 for ; Thu, 30 Mar 2023 15:25:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233100AbjC3PYw (ORCPT ); Thu, 30 Mar 2023 11:24:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40942 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233064AbjC3PY1 (ORCPT ); Thu, 30 Mar 2023 11:24:27 -0400 Received: from fudo.makrotopia.org (fudo.makrotopia.org [IPv6:2a07:2ec0:3002::71]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4D2EECC2F; Thu, 30 Mar 2023 08:23:58 -0700 (PDT) Received: from local by fudo.makrotopia.org with esmtpsa (TLS1.3:TLS_AES_256_GCM_SHA384:256) (Exim 4.96) (envelope-from ) id 1phu7Q-0006kH-1P; Thu, 30 Mar 2023 17:23:16 +0200 Date: Thu, 30 Mar 2023 16:23:13 +0100 From: Daniel Golle To: netdev@vger.kernel.org, linux-mediatek@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux@armlinux.org.uk, linux-kernel@vger.kernel.org, Andrew Lunn , =?utf-8?B?QXLEsW7DpyDDnG5hbA==?= , 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 Cc: Sam Shih , Lorenzo Bianconi , John Crispin , Felix Fietkau Subject: [PATCH net-next 12/15] net: dsa: mt7530: skip locking if MDIO bus isn't present Message-ID: <10cf68a82095fc136c1bb1af3f48bb3fef21e71b.1680180959.git.daniel@makrotopia.org> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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. Reviewed-by: Andrew Lunn Signed-off-by: Daniel Golle --- 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 ea8d8e669aacc..3a4682e71e746 100644 --- a/drivers/net/dsa/mt7530.c +++ b/drivers/net/dsa/mt7530.c @@ -145,13 +145,15 @@ 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); } =20 static void mt7530_mutex_unlock(struct mt7530_priv *priv) { - mutex_unlock(&priv->bus->mdio_lock); + if (priv->bus) + mutex_unlock(&priv->bus->mdio_lock); } =20 static void --=20 2.39.2