From patchwork Wed Dec 23 17:21:54 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wolfram Sang X-Patchwork-Id: 351618 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=-16.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham 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 61454C43331 for ; Wed, 23 Dec 2020 17:22:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2DEE9207D8 for ; Wed, 23 Dec 2020 17:22:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726012AbgLWRWp (ORCPT ); Wed, 23 Dec 2020 12:22:45 -0500 Received: from www.zeus03.de ([194.117.254.33]:41318 "EHLO mail.zeus03.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725957AbgLWRWp (ORCPT ); Wed, 23 Dec 2020 12:22:45 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=simple; d=sang-engineering.com; h= from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; s=k1; bh=1JW78K30O2RbXi D/46e66qs9goat0S+NhqzHuG4kNXs=; b=StiL3grPgjnquBqYamH1YGAMWtuMyv KdpGVlNBoPCDRNj1afIEt0U1SxshbwdmZ4Sv5WmUm4EFmP06E9tHhgAuILzjwLs+ ewQFHed0DZsUS9JgC2lJYVR9TYFB4pl3K/k1oxTdjddN0P8HA7zMxwdQBKAUdzaw Epd700XulFAtI= Received: (qmail 543679 invoked from network); 23 Dec 2020 18:22:03 +0100 Received: by mail.zeus03.de with ESMTPSA (TLS_AES_256_GCM_SHA384 encrypted, authenticated); 23 Dec 2020 18:22:03 +0100 X-UD-Smtp-Session: l3s3148p1@D9D77SS3vOdUhszw From: Wolfram Sang To: linux-i2c@vger.kernel.org Cc: linux-renesas-soc@vger.kernel.org, Kuninori Morimoto , Yoshihiro Shimoda , Wolfram Sang Subject: [PATCH 4/4] i2c: rcar: protect against supurious interrupts on V3U Date: Wed, 23 Dec 2020 18:21:54 +0100 Message-Id: <20201223172154.34462-5-wsa+renesas@sang-engineering.com> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201223172154.34462-1-wsa+renesas@sang-engineering.com> References: <20201223172154.34462-1-wsa+renesas@sang-engineering.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org V3U creates spurious interrupts which we need to handle. This costs time until BUS_PHASE_DATA can be activated which is problematic for Gen2 SoCs and earlier. Because of this we introduce two interrupt handlers here which will call a generic main irq function once the timing critical stuff is done. Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-rcar.c | 57 ++++++++++++++++++++++++++--------- 1 file changed, 43 insertions(+), 14 deletions(-) diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c index 3c9c3a6f7ac8..12f6d452c0f7 100644 --- a/drivers/i2c/busses/i2c-rcar.c +++ b/drivers/i2c/busses/i2c-rcar.c @@ -625,20 +625,11 @@ static bool rcar_i2c_slave_irq(struct rcar_i2c_priv *priv) * generated. It turned out that taking a spinlock at the beginning of the ISR * was already causing repeated messages. Thus, this driver was converted to * the now lockless behaviour. Please keep this in mind when hacking the driver. + * R-Car Gen3 seems to have this fixed but earlier versions than R-Car Gen2 are + * likely affected. Therefore, we have different interrupt handler entries. */ -static irqreturn_t rcar_i2c_irq(int irq, void *ptr) +static irqreturn_t rcar_i2c_irq(int irq, struct rcar_i2c_priv *priv, u32 msr) { - struct rcar_i2c_priv *priv = ptr; - u32 msr; - - /* Clear START or STOP immediately, except for REPSTART after read */ - if (likely(!(priv->flags & ID_P_REP_AFTER_RD))) - rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_DATA); - - msr = rcar_i2c_read(priv, ICMSR); - - /* Only handle interrupts that are currently enabled */ - msr &= rcar_i2c_read(priv, ICMIER); if (!msr) { if (rcar_i2c_slave_irq(priv)) return IRQ_HANDLED; @@ -682,6 +673,41 @@ static irqreturn_t rcar_i2c_irq(int irq, void *ptr) return IRQ_HANDLED; } +static irqreturn_t rcar_i2c_gen2_irq(int irq, void *ptr) +{ + struct rcar_i2c_priv *priv = ptr; + u32 msr; + + /* Clear START or STOP immediately, except for REPSTART after read */ + if (likely(!(priv->flags & ID_P_REP_AFTER_RD))) + rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_DATA); + + /* Only handle interrupts that are currently enabled */ + msr = rcar_i2c_read(priv, ICMSR); + msr &= rcar_i2c_read(priv, ICMIER); + + return rcar_i2c_irq(irq, priv, msr); +} + +static irqreturn_t rcar_i2c_gen3_irq(int irq, void *ptr) +{ + struct rcar_i2c_priv *priv = ptr; + u32 msr; + + /* Only handle interrupts that are currently enabled */ + msr = rcar_i2c_read(priv, ICMSR); + msr &= rcar_i2c_read(priv, ICMIER); + + /* + * Clear START or STOP immediately, except for REPSTART after read or + * if a spurious interrupt was detected. + */ + if (likely(!(priv->flags & ID_P_REP_AFTER_RD) && msr)) + rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_DATA); + + return rcar_i2c_irq(irq, priv, msr); +} + static struct dma_chan *rcar_i2c_request_dma_chan(struct device *dev, enum dma_transfer_direction dir, dma_addr_t port_addr) @@ -929,6 +955,7 @@ static int rcar_i2c_probe(struct platform_device *pdev) struct i2c_adapter *adap; struct device *dev = &pdev->dev; unsigned long irqflags = 0; + irqreturn_t (*irqhandler)(int irq, void *ptr) = rcar_i2c_gen3_irq; int ret; /* Otherwise logic will break because some bytes must always use PIO */ @@ -977,8 +1004,10 @@ static int rcar_i2c_probe(struct platform_device *pdev) rcar_i2c_write(priv, ICSAR, 0); /* Gen2: must be 0 if not using slave */ - if (priv->devtype < I2C_RCAR_GEN3) + if (priv->devtype < I2C_RCAR_GEN3) { irqflags |= IRQF_NO_THREAD; + irqhandler = rcar_i2c_gen2_irq; + } if (priv->devtype == I2C_RCAR_GEN3) { priv->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL); @@ -999,7 +1028,7 @@ static int rcar_i2c_probe(struct platform_device *pdev) priv->flags |= ID_P_HOST_NOTIFY; priv->irq = platform_get_irq(pdev, 0); - ret = devm_request_irq(dev, priv->irq, rcar_i2c_irq, irqflags, dev_name(dev), priv); + ret = devm_request_irq(dev, priv->irq, irqhandler, irqflags, dev_name(dev), priv); if (ret < 0) { dev_err(dev, "cannot get irq %d\n", priv->irq); goto out_pm_disable;