From mboxrd@z Thu Jan 1 00:00:00 1970 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=-9.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 8902FC46460 for ; Wed, 22 May 2019 09:00:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5675F20856 for ; Wed, 22 May 2019 09:00:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=sifive.com header.i=@sifive.com header.b="ipstSQ6Y" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728981AbfEVJAe (ORCPT ); Wed, 22 May 2019 05:00:34 -0400 Received: from mail-pf1-f194.google.com ([209.85.210.194]:39832 "EHLO mail-pf1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728950AbfEVJAd (ORCPT ); Wed, 22 May 2019 05:00:33 -0400 Received: by mail-pf1-f194.google.com with SMTP id z26so976074pfg.6 for ; Wed, 22 May 2019 02:00:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sifive.com; s=google; h=from:to:subject:date:message-id:in-reply-to:references; bh=5JJ5fP/lDTAT9lV7xByh9EU/tkZg+0nZnzbUrujyoZg=; b=ipstSQ6Yr0YiVJDWV10kcpbrfJjjHLhMzmh0R5zJ0BRJ+/uTs2g2QHIxsuPKQ9hmH9 a24/Bw47Q8KJcg3WmCn4r/ZnkA4KSA/RDRCDwK86wMVfQMxATbmlfsUoAx2y5MY0a20U 2mPSaY9jLKmzoq3FZfQgeLl1LPU6aYtrU3Woz+gPmsII1osvIn5uwfigeZvUmWTnTsqR yB6f578Tj/woyeCnfR8A1Af7p15Qr0nilHqC1+kVfqjdEDa31Q26qZn+Ltq0RwPJPmCo XcIRfUhe/VBjJ4GIz8gC+CEzshZgqS66hvdy4SIzaYNMnhhJPFE9V+n+2iuZMITLBZ6m Co7w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:subject:date:message-id:in-reply-to :references; bh=5JJ5fP/lDTAT9lV7xByh9EU/tkZg+0nZnzbUrujyoZg=; b=V2mmaETC88UVvlgSPb0trHhhZ6XLcDVAEx9ruA9diBBOFQElIPMfgRoYxjmTeAjRAL GW7l2Eb9YtDcpa70goIscB6HniD0msaxE234mNgDUntnnylgins5FvOwGvG6fq0FCfYM 3e+ZoOAaRKvteOjieV2BnWSe0oHjIC7Glukb5/s26y66PG+1fPPS/7Xna3CCj/VUp9Dg WP6RHRGogaWKTEe+inMRlRLlm9akQ/x+2GBpFQmBUlC6SunbePv1+qbm74w8Vc3dAqfp DYO/BwfoMFcagYHfRJOplCspyvxmmDv7+/V8Bp0FnNUgonskAaIIhh/VPgAHJFK6rZSp UZaA== X-Gm-Message-State: APjAAAUBF86GWFXzMcG0TIDzNNcsSiTPoFOvwaFv8PV5Yl272FxeFHeE hCFiSe8Z6fO9jvDRPM/dnYz7bQ== X-Google-Smtp-Source: APXvYqyTbIoq0TYdEGaDw9+FgNSRP6qiBMs6r2PxBr8XOsu6jCNDP0zLQ8CqoSSX0f68BgiR1mmkAQ== X-Received: by 2002:a63:4852:: with SMTP id x18mr75552399pgk.14.1558515633088; Wed, 22 May 2019 02:00:33 -0700 (PDT) Received: from buildserver-90.open-silicon.com ([114.143.65.226]) by smtp.googlemail.com with ESMTPSA id z6sm42465905pfr.135.2019.05.22.02.00.29 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Wed, 22 May 2019 02:00:32 -0700 (PDT) From: Sagar Shrikant Kadam To: robh+dt@kernel.org, mark.rutland@arm.com, peter@korsgaard.com, andrew@lunn.ch, palmer@sifive.com, paul.walmsley@sifive.com, sagar.kadam@sifive.com, linux-i2c@vger.kernel.org, devicetree@vger.kernel.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v7 3/3] i2c-ocores: sifive: add polling mode workaround for FU540-C000 SoC. Date: Wed, 22 May 2019 14:29:34 +0530 Message-Id: <1558515574-11155-4-git-send-email-sagar.kadam@sifive.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1558515574-11155-1-git-send-email-sagar.kadam@sifive.com> References: <1558515574-11155-1-git-send-email-sagar.kadam@sifive.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The i2c-ocore driver already has a polling mode interface.But it needs a workaround for FU540 Chipset on HiFive unleashed board (RevA00). There is an erratum in FU540 chip that prevents interrupt driven i2c transfers from working, and also the I2C controller's interrupt bit cannot be cleared if set, due to this the existing i2c polling mode interface added in mainline earlier doesn't work, and CPU stall's infinitely, when-ever i2c transfer is initiated. Ref: commit dd7dbf0eb090 ("i2c: ocores: refactor setup for polling") The workaround / fix under OCORES_FLAG_BROKEN_IRQ is particularly for FU540-COOO SoC. The polling function identifies a SiFive device based on the device node and enables the workaround. Signed-off-by: Sagar Shrikant Kadam --- drivers/i2c/busses/i2c-ocores.c | 24 ++++++++++++++++++++++-- 1 file changed, 22 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/busses/i2c-ocores.c b/drivers/i2c/busses/i2c-ocores.c index b334fa2..4117f1a 100644 --- a/drivers/i2c/busses/i2c-ocores.c +++ b/drivers/i2c/busses/i2c-ocores.c @@ -35,6 +35,7 @@ struct ocores_i2c { int iobase; u32 reg_shift; u32 reg_io_width; + unsigned long flags; wait_queue_head_t wait; struct i2c_adapter adap; struct i2c_msg *msg; @@ -84,6 +85,8 @@ struct ocores_i2c { #define TYPE_GRLIB 1 #define TYPE_SIFIVE_REV0 2 +#define OCORES_FLAG_BROKEN_IRQ BIT(1) /* Broken IRQ for FU540-C000 SoC */ + static void oc_setreg_8(struct ocores_i2c *i2c, int reg, u8 value) { iowrite8(value, i2c->base + (reg << i2c->reg_shift)); @@ -236,9 +239,12 @@ static irqreturn_t ocores_isr(int irq, void *dev_id) struct ocores_i2c *i2c = dev_id; u8 stat = oc_getreg(i2c, OCI2C_STATUS); - if (!(stat & OCI2C_STAT_IF)) + if (i2c->flags & OCORES_FLAG_BROKEN_IRQ) { + if ((stat & OCI2C_STAT_IF) && !(stat & OCI2C_STAT_BUSY)) + return IRQ_NONE; + } else if (!(stat & OCI2C_STAT_IF)) { return IRQ_NONE; - + } ocores_process(i2c, stat); return IRQ_HANDLED; @@ -353,6 +359,11 @@ static void ocores_process_polling(struct ocores_i2c *i2c) ret = ocores_isr(-1, i2c); if (ret == IRQ_NONE) break; /* all messages have been transferred */ + else { + if (i2c->flags & OCORES_FLAG_BROKEN_IRQ) + if (i2c->state == STATE_DONE) + break; + } } } @@ -595,6 +606,7 @@ static int ocores_i2c_probe(struct platform_device *pdev) { struct ocores_i2c *i2c; struct ocores_i2c_platform_data *pdata; + const struct of_device_id *match; struct resource *res; int irq; int ret; @@ -677,6 +689,14 @@ static int ocores_i2c_probe(struct platform_device *pdev) irq = platform_get_irq(pdev, 0); if (irq == -ENXIO) { ocores_algorithm.master_xfer = ocores_xfer_polling; + + /* + * Set in OCORES_FLAG_BROKEN_IRQ to enable workaround for + * FU540-C000 SoC in polling mode. + */ + match = of_match_node(ocores_i2c_match, pdev->dev.of_node); + if (match && (long)match->data == TYPE_SIFIVE_REV0) + i2c->flags |= OCORES_FLAG_BROKEN_IRQ; } else { if (irq < 0) return irq; -- 1.9.1