From patchwork Mon Aug 2 13:10:32 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oleksij Rempel X-Patchwork-Id: 12413955 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BBBB3C4320E for ; Mon, 2 Aug 2021 13:11:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A1F0361057 for ; Mon, 2 Aug 2021 13:11:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233918AbhHBNLU (ORCPT ); Mon, 2 Aug 2021 09:11:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57288 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233932AbhHBNLB (ORCPT ); Mon, 2 Aug 2021 09:11:01 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 07A77C061798 for ; Mon, 2 Aug 2021 06:10:51 -0700 (PDT) Received: from dude.hi.pengutronix.de ([2001:67c:670:100:1d::7]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1mAXiK-0003MY-Om; Mon, 02 Aug 2021 15:10:40 +0200 Received: from ore by dude.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1mAXiJ-00006S-G0; Mon, 02 Aug 2021 15:10:39 +0200 From: Oleksij Rempel To: Andrew Lunn , Vivien Didelot , Florian Fainelli , Vladimir Oltean , "David S. Miller" , Jakub Kicinski , Russell King Cc: Oleksij Rempel , Pengutronix Kernel Team , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org Subject: [PATCH net-next v3 1/6] net: dsa: qca: ar9331: reorder MDIO write sequence Date: Mon, 2 Aug 2021 15:10:32 +0200 Message-Id: <20210802131037.32326-2-o.rempel@pengutronix.de> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210802131037.32326-1-o.rempel@pengutronix.de> References: <20210802131037.32326-1-o.rempel@pengutronix.de> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::7 X-SA-Exim-Mail-From: ore@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-mips@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org In case of this switch we work with 32bit registers on top of 16bit bus. Some registers (for example access to forwarding database) have trigger bit on the first 16bit half of request and the result + configuration of request in the second half. Without this patch, we would trigger database operation and overwrite result in one run. To make it work properly, we should do the second part of transfer before the first one is done. So far, this rule seems to work for all registers on this switch. Signed-off-by: Oleksij Rempel Reviewed-by: Andrew Lunn Reviewed-by: Vladimir Oltean --- drivers/net/dsa/qca/ar9331.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/drivers/net/dsa/qca/ar9331.c b/drivers/net/dsa/qca/ar9331.c index ca2ad77b71f1..6686192e1883 100644 --- a/drivers/net/dsa/qca/ar9331.c +++ b/drivers/net/dsa/qca/ar9331.c @@ -837,16 +837,24 @@ static int ar9331_mdio_write(void *ctx, u32 reg, u32 val) return 0; } - ret = __ar9331_mdio_write(sbus, AR9331_SW_MDIO_PHY_MODE_REG, reg, val); + /* In case of this switch we work with 32bit registers on top of 16bit + * bus. Some registers (for example access to forwarding database) have + * trigger bit on the first 16bit half of request, the result and + * configuration of request in the second half. + * To make it work properly, we should do the second part of transfer + * before the first one is done. + */ + ret = __ar9331_mdio_write(sbus, AR9331_SW_MDIO_PHY_MODE_REG, reg + 2, + val >> 16); if (ret < 0) goto error; - ret = __ar9331_mdio_write(sbus, AR9331_SW_MDIO_PHY_MODE_REG, reg + 2, - val >> 16); + ret = __ar9331_mdio_write(sbus, AR9331_SW_MDIO_PHY_MODE_REG, reg, val); if (ret < 0) goto error; return 0; + error: dev_err_ratelimited(&sbus->dev, "Bus error. Failed to write register.\n"); return ret;