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=-9.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 B35EBC43461 for ; Thu, 10 Sep 2020 21:23:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5750221D92 for ; Thu, 10 Sep 2020 21:23:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="jaitZhUb" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728104AbgIJVXF (ORCPT ); Thu, 10 Sep 2020 17:23:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54998 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731088AbgIJOXu (ORCPT ); Thu, 10 Sep 2020 10:23:50 -0400 Received: from mail-ed1-x542.google.com (mail-ed1-x542.google.com [IPv6:2a00:1450:4864:20::542]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D9B58C061799; Thu, 10 Sep 2020 07:12:27 -0700 (PDT) Received: by mail-ed1-x542.google.com with SMTP id g4so6503788edk.0; Thu, 10 Sep 2020 07:12:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=dzd1FhP6wV6XF+6vHaJvcn3K74C1JBUgllVSp1uGIpg=; b=jaitZhUb+eTL8Xzlc9mGQ3uihTDzSf5eT6FkrCrVMj+lSXjJjfIthuvZGvUj4ZcSXk vPj1WdYcuCS+4TI+e00BuZQpK9ddElJYo/J7/u3FUYFCAlB6IKWFQYZ4//mSMD3/68C2 K/oULINcwiivYM4nnoUC/ET8clLK9x4FDNCeNltS60BX35TouhAnOHy+lRm7pKeE892x slLzWxJAuFyQHH8dlp4+FL8NNIUrEBOsG1b1OYpPuMDvmUa992RJZoG1KLCsIJAmvSpQ wL62Xem14rm0BxA04iX8K64HLl+VotrSd1yZc6L5fhUZVuc+Ttoyc2VOCgFTG6Y/l53q KAQw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=dzd1FhP6wV6XF+6vHaJvcn3K74C1JBUgllVSp1uGIpg=; b=bgW8QT2MlVF7HqilmxFEPIJrkfqWg1mqPsPH3LSAEjs74abM4XndZACZZDa/Cibc8V E45nI3ISzFedSCoaDA49pBfIncyXEDNWh1IEsA5NdNRXaOszK/Gra/nhBI0z3d6nW3sJ yKqNBcKjH6ZQPNYjCj+9SFv4PVARJOlTk6+rtlJORQ9yCpTFu1dRNWgj9axkSkQNYNHN A+vo29oJHIDuUWOmn1SDTH3U0+GSCTiWgrjhbKU449jmHcElVld565ak6/P29jLr2mgC dFLK0zHQVp2Yu+ccHHu6ZIe8Bc7kGuMPfizj6BurvgjQRI0SqEwghR3cxJTTtSchZRJo xAdA== X-Gm-Message-State: AOAM532XyW30SLZAEflodgLp7acAUSxlxcpMc5r5HEAfAau/cb7vumye FodhJBqY9GSKZymFSb/DOQU= X-Google-Smtp-Source: ABdhPJy68TRzObWFqW/b+IO0EouOc2uoLitf2fEyX0Oyo+CI3kjH05R3DZQhQ3BVh3dCD1o8RpnECg== X-Received: by 2002:a50:875c:: with SMTP id 28mr9499767edv.20.1599747146459; Thu, 10 Sep 2020 07:12:26 -0700 (PDT) Received: from BV030612LT ([188.24.159.61]) by smtp.gmail.com with ESMTPSA id b13sm7591811edf.89.2020.09.10.07.12.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 10 Sep 2020 07:12:25 -0700 (PDT) Date: Thu, 10 Sep 2020 17:12:23 +0300 From: Cristian Ciocaltea To: Manivannan Sadhasivam Cc: Andreas =?iso-8859-1?Q?F=E4rber?= , linux-i2c@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-actions@lists.infradead.org Subject: Re: [PATCH v2 1/1] i2c: busses: Add support for atomic transfers in Actions Semi Owl driver Message-ID: <20200910141223.GA447296@BV030612LT> References: <20200909151748.GA11397@mani> <20200909165915.GA387239@BV030612LT> <20200910030225.GA10495@mani> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200910030225.GA10495@mani> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 10, 2020 at 08:32:25AM +0530, Manivannan Sadhasivam wrote: > On 0909, Cristian Ciocaltea wrote: > > Hi Mani, > > > > Thanks for the review! > > > > On Wed, Sep 09, 2020 at 08:47:48PM +0530, Manivannan Sadhasivam wrote: > > > Hi Cristi, > > > > > > On 0908, Cristian Ciocaltea wrote: > > > > Atomic transfers are required to properly power off a machine through > > > > an I2C controlled PMIC, such as the Actions Semi ATC260x series. > > > > > > > > System shutdown may happen with interrupts being disabled and, as a > > > > consequence, the kernel may hang if the driver does not support atomic > > > > transfers. > > > > > > > > This functionality is essentially implemented by polling the FIFO > > > > Status register until either Command Execute Completed or NACK Error > > > > bits are set. > > > > > > > > > > Thanks for the patch! I just have couple of minor comments and other > > > than that it looks good to me. > > > > > > > Signed-off-by: Cristian Ciocaltea > > > > --- > > > > Changes in v2: > > > > - Dropped unused return codes from owl_i2c_xfer_data(), per Mani's review > > > > - Rebased patch on v5.9-rc4 > > > > > > > > drivers/i2c/busses/i2c-owl.c | 78 ++++++++++++++++++++++++++---------- > > > > 1 file changed, 57 insertions(+), 21 deletions(-) > > > > > > > > diff --git a/drivers/i2c/busses/i2c-owl.c b/drivers/i2c/busses/i2c-owl.c > > > > index 672f1f239bd6..29605257831f 100644 > > > > --- a/drivers/i2c/busses/i2c-owl.c > > > > +++ b/drivers/i2c/busses/i2c-owl.c > > > > @@ -14,6 +14,7 @@ > > > > #include > > > > #include > > > > #include > > > > +#include > > > > #include > > > > #include > > > > > > > > @@ -76,6 +77,7 @@ > > > > #define OWL_I2C_FIFOCTL_TFR BIT(2) > > > > > > > > /* I2Cc_FIFOSTAT Bit Mask */ > > > > +#define OWL_I2C_FIFOSTAT_CECB BIT(0) > > > > #define OWL_I2C_FIFOSTAT_RNB BIT(1) > > > > #define OWL_I2C_FIFOSTAT_RFE BIT(2) > > > > #define OWL_I2C_FIFOSTAT_TFF BIT(5) > > > > @@ -83,7 +85,8 @@ > > > > #define OWL_I2C_FIFOSTAT_RFD GENMASK(15, 8) > > > > > > > > /* I2C bus timeout */ > > > > -#define OWL_I2C_TIMEOUT msecs_to_jiffies(4 * 1000) > > > > +#define OWL_I2C_TIMEOUT_MS (4 * 1000) > > > > +#define OWL_I2C_TIMEOUT msecs_to_jiffies(OWL_I2C_TIMEOUT_MS) > > > > > > > > #define OWL_I2C_MAX_RETRIES 50 > > > > > > > > @@ -161,29 +164,25 @@ static void owl_i2c_set_freq(struct owl_i2c_dev *i2c_dev) > > > > writel(OWL_I2C_DIV_FACTOR(val), i2c_dev->base + OWL_I2C_REG_CLKDIV); > > > > } > > > > > > > > -static irqreturn_t owl_i2c_interrupt(int irq, void *_dev) > > > > +static void owl_i2c_xfer_data(struct owl_i2c_dev *i2c_dev) > > > > { > > > > - struct owl_i2c_dev *i2c_dev = _dev; > > > > struct i2c_msg *msg = i2c_dev->msg; > > > > - unsigned long flags; > > > > unsigned int stat, fifostat; > > > > > > > > - spin_lock_irqsave(&i2c_dev->lock, flags); > > > > - > > > > i2c_dev->err = 0; > > > > > > > > /* Handle NACK from slave */ > > > > fifostat = readl(i2c_dev->base + OWL_I2C_REG_FIFOSTAT); > > > > if (fifostat & OWL_I2C_FIFOSTAT_RNB) { > > > > i2c_dev->err = -ENXIO; > > > > - goto stop; > > > > + return; > > > > } > > > > > > > > /* Handle bus error */ > > > > stat = readl(i2c_dev->base + OWL_I2C_REG_STAT); > > > > if (stat & OWL_I2C_STAT_BEB) { > > > > i2c_dev->err = -EIO; > > > > - goto stop; > > > > + return; > > > > } > > > > > > > > /* Handle FIFO read */ > > > > @@ -196,18 +195,28 @@ static irqreturn_t owl_i2c_interrupt(int irq, void *_dev) > > > > } else { > > > > /* Handle the remaining bytes which were not sent */ > > > > while (!(readl(i2c_dev->base + OWL_I2C_REG_FIFOSTAT) & > > > > - OWL_I2C_FIFOSTAT_TFF) && i2c_dev->msg_ptr < msg->len) { > > > > + OWL_I2C_FIFOSTAT_TFF) && i2c_dev->msg_ptr < msg->len) { > > > > > > Spurious change? > > > > I have just fixed a small indentation issue (removed extra space char > > in front of OWL_I2C...). I will revert it if you think it's not the right > > context for doing this (located ~10 lines bellow the previous edit). > > > > The extra space was there to align with the starting of 'readl', so please keep > it as it is. Right, sorry! I aligned it with the other 'readl' a few lines above and I missed the extra offset caused by the '!' operator. > > > > writel(msg->buf[i2c_dev->msg_ptr++], > > > > i2c_dev->base + OWL_I2C_REG_TXDAT); > > > > } > > > > } > > > > +} > > > > + > > > > +static irqreturn_t owl_i2c_interrupt(int irq, void *_dev) > > > > +{ > > > > + struct owl_i2c_dev *i2c_dev = _dev; > > > > + unsigned long flags; > > > > + > > > > + spin_lock_irqsave(&i2c_dev->lock, flags); > > > > + > > > > + owl_i2c_xfer_data(i2c_dev); > > > > > > > > -stop: > > > > /* Clear pending interrupts */ > > > > owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_STAT, > > > > OWL_I2C_STAT_IRQP, true); > > > > > > > > complete_all(&i2c_dev->msg_complete); > > > > + > > > > spin_unlock_irqrestore(&i2c_dev->lock, flags); > > > > > > > > return IRQ_HANDLED; > > > > @@ -235,8 +244,8 @@ static int owl_i2c_check_bus_busy(struct i2c_adapter *adap) > > > > return 0; > > > > } > > > > > > > > -static int owl_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, > > > > - int num) > > > > +static int owl_i2c_xfer_common(struct i2c_adapter *adap, struct i2c_msg *msgs, > > > > + int num, bool atomic) > > > > { > > > > struct owl_i2c_dev *i2c_dev = i2c_get_adapdata(adap); > > > > struct i2c_msg *msg; > > > > @@ -280,11 +289,12 @@ static int owl_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, > > > > goto err_exit; > > > > } > > > > > > > > - reinit_completion(&i2c_dev->msg_complete); > > > > + if (!atomic) > > > > + reinit_completion(&i2c_dev->msg_complete); > > > > > > > > - /* Enable I2C controller interrupt */ > > > > + /* Enable/disable I2C controller interrupt */ > > > > owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_CTL, > > > > - OWL_I2C_CTL_IRQE, true); > > > > + OWL_I2C_CTL_IRQE, !atomic); > > > > > > > > /* > > > > * Select: FIFO enable, Master mode, Stop enable, Data count enable, > > > > @@ -352,20 +362,33 @@ static int owl_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, > > > > > > > > spin_unlock_irqrestore(&i2c_dev->lock, flags); > > > > > > > > - time_left = wait_for_completion_timeout(&i2c_dev->msg_complete, > > > > - adap->timeout); > > > > + if (atomic) { > > > > + /* Wait for Command Execute Completed or NACK Error bits */ > > > > + ret = readl_poll_timeout_atomic(i2c_dev->base + OWL_I2C_REG_FIFOSTAT, > > > > + val, val & (OWL_I2C_FIFOSTAT_CECB | > > > > + OWL_I2C_FIFOSTAT_RNB), > > > > + 10, OWL_I2C_TIMEOUT_MS * 1000); > > > > + } else { > > > > + time_left = wait_for_completion_timeout(&i2c_dev->msg_complete, > > > > + adap->timeout); > > > > + if (!time_left) > > > > + ret = -ETIMEDOUT; > > > > + } > > > > > > > > spin_lock_irqsave(&i2c_dev->lock, flags); > > > > - if (time_left == 0) { > > > > + > > > > + if (ret) { > > > > dev_err(&adap->dev, "Transaction timed out\n"); > > > > /* Send stop condition and release the bus */ > > > > owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_CTL, > > > > OWL_I2C_CTL_GBCC_STOP | OWL_I2C_CTL_RB, > > > > true); > > > > - ret = -ETIMEDOUT; > > > > goto err_exit; > > > > } > > > > > > > > + if (atomic) > > > > + owl_i2c_xfer_data(i2c_dev); > > > > > > You are not clearing the pending interrupts here. > > > > I assumed this is not needed for atomic contexts since the controller > > interrupt is disabled (please see the comment above: Enable/disable I2C > > controller interrupt). > > > > Otherwise I will simply move the clear pending interrupts code from > > owl_i2c_interrupt() to owl_i2c_xfer_data(). > > > > Hmm. My intention was to say that we are not clearing the error bits when they > happen but I misinterpreted that setting IRQP will take care of that but it > doesn't. > > So I think you should submit a patch which writes to RNB and BEB fields when > they are set (writing 1 will clear the interrupts) and ignore my previous > comment. Sure, I can handle this. I assume this should be a separate patch, to be applied before the current patch. Should I submit a patch series instead? Thanks, Cristi > Thanks, > Mani > > > > Thanks, > > > Mani > > > > > > > + > > > > ret = i2c_dev->err < 0 ? i2c_dev->err : num; > > > > > > > > err_exit: > > > > @@ -379,9 +402,22 @@ static int owl_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, > > > > return ret; > > > > } > > > > > > > > +static int owl_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, > > > > + int num) > > > > +{ > > > > + return owl_i2c_xfer_common(adap, msgs, num, false); > > > > +} > > > > + > > > > +static int owl_i2c_xfer_atomic(struct i2c_adapter *adap, > > > > + struct i2c_msg *msgs, int num) > > > > +{ > > > > + return owl_i2c_xfer_common(adap, msgs, num, true); > > > > +} > > > > + > > > > static const struct i2c_algorithm owl_i2c_algorithm = { > > > > - .master_xfer = owl_i2c_master_xfer, > > > > - .functionality = owl_i2c_func, > > > > + .master_xfer = owl_i2c_xfer, > > > > + .master_xfer_atomic = owl_i2c_xfer_atomic, > > > > + .functionality = owl_i2c_func, > > > > }; > > > > > > > > static const struct i2c_adapter_quirks owl_i2c_quirks = { > > > > -- > > > > 2.28.0 > > > > > > > > Kind regards, > > Cristi 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=-9.5 required=3.0 tests=BAYES_00,DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED,DKIM_VALID,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 143C8C43461 for ; Thu, 10 Sep 2020 14:13:51 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A147E206B7 for ; Thu, 10 Sep 2020 14:13:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="ZNYokQO6"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="jaitZhUb" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A147E206B7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=piS8XACIC3jos4tSEAq6bmYRrX1+lc2N12KvJCAP7FM=; b=ZNYokQO6RbbHe0HaaJjbzTbUy Y64o/uebFjzNAnh2l3jKo0pOtRq26vKdOJDqTUoKj7d0syj0NAD1ZmgsUOFBQ1C7zU9w1mV78Zlzt qW1DKPlk4gJSB+ey+bAdst/dsVWc4IZdDhg3WyjHpk2V5AXzUB7aAimnR1YelgJxpLCyg7VTHPv6U Rm9kE5QHV2g4i2FeLWRmXry+kwtATAGyHQSdudYsKb9LJhRhtitizwB7aWW+GtfqjyWeMAOTW8vHC Rs/AL5KqHKqr2jPPWgIMeJ7QGDW6wxPq6lodg9VZT2tR6ybMp0+4YxSB7il3++vLuguHIAnZmAscc XaMP3qg5g==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kGNJO-0005Hn-Ax; Thu, 10 Sep 2020 14:12:30 +0000 Received: from mail-ed1-x541.google.com ([2a00:1450:4864:20::541]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kGNJL-0005H6-Se; Thu, 10 Sep 2020 14:12:28 +0000 Received: by mail-ed1-x541.google.com with SMTP id i1so6492938edv.2; Thu, 10 Sep 2020 07:12:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=dzd1FhP6wV6XF+6vHaJvcn3K74C1JBUgllVSp1uGIpg=; b=jaitZhUb+eTL8Xzlc9mGQ3uihTDzSf5eT6FkrCrVMj+lSXjJjfIthuvZGvUj4ZcSXk vPj1WdYcuCS+4TI+e00BuZQpK9ddElJYo/J7/u3FUYFCAlB6IKWFQYZ4//mSMD3/68C2 K/oULINcwiivYM4nnoUC/ET8clLK9x4FDNCeNltS60BX35TouhAnOHy+lRm7pKeE892x slLzWxJAuFyQHH8dlp4+FL8NNIUrEBOsG1b1OYpPuMDvmUa992RJZoG1KLCsIJAmvSpQ wL62Xem14rm0BxA04iX8K64HLl+VotrSd1yZc6L5fhUZVuc+Ttoyc2VOCgFTG6Y/l53q KAQw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=dzd1FhP6wV6XF+6vHaJvcn3K74C1JBUgllVSp1uGIpg=; b=qCZuupod7NPC+1SLnsd8Lydc/YC/zMuKWfi+r6s53oJqMAeXXg2UEjqNT0Bknlb+nS MckKIQzesI+z4A6ennIwyfjYdYJSYA5doCwQEpQ2UdEndHNzlmWM95EdJ/j+pjxgRGUm +92zzamT0F6hmQvZwdI44GAZN50dVAf/J5PPrjMFYUSjBB5G2rF83kwAW7fLvoXJMIm1 cT/9Bh0INMMXMxNjwtIEXJNvP0FWbdMDqQRxnO/4xY3IbMDiZfH9Ep9wIGv7TaTTCZK6 scE9lG7iSM/kGiw6VTXXHqT/DAAHF0iatfFcP0wjITfHf6pNXRFUT/ufSsTSbPzqBm25 OSFQ== X-Gm-Message-State: AOAM532mLviy0H9CQWgZUeCfJh/ACor9HMSV7JBBcXEvoydhlbIl5/Mc 5tBp2ZgpafLTueBpOLzUNS4= X-Google-Smtp-Source: ABdhPJy68TRzObWFqW/b+IO0EouOc2uoLitf2fEyX0Oyo+CI3kjH05R3DZQhQ3BVh3dCD1o8RpnECg== X-Received: by 2002:a50:875c:: with SMTP id 28mr9499767edv.20.1599747146459; Thu, 10 Sep 2020 07:12:26 -0700 (PDT) Received: from BV030612LT ([188.24.159.61]) by smtp.gmail.com with ESMTPSA id b13sm7591811edf.89.2020.09.10.07.12.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 10 Sep 2020 07:12:25 -0700 (PDT) Date: Thu, 10 Sep 2020 17:12:23 +0300 From: Cristian Ciocaltea To: Manivannan Sadhasivam Subject: Re: [PATCH v2 1/1] i2c: busses: Add support for atomic transfers in Actions Semi Owl driver Message-ID: <20200910141223.GA447296@BV030612LT> References: <20200909151748.GA11397@mani> <20200909165915.GA387239@BV030612LT> <20200910030225.GA10495@mani> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200910030225.GA10495@mani> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200910_101227_948154_9E1B3D68 X-CRM114-Status: GOOD ( 48.11 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-kernel@vger.kernel.org, linux-actions@lists.infradead.org, Andreas =?iso-8859-1?Q?F=E4rber?= , linux-arm-kernel@lists.infradead.org, linux-i2c@vger.kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Sep 10, 2020 at 08:32:25AM +0530, Manivannan Sadhasivam wrote: > On 0909, Cristian Ciocaltea wrote: > > Hi Mani, > > > > Thanks for the review! > > > > On Wed, Sep 09, 2020 at 08:47:48PM +0530, Manivannan Sadhasivam wrote: > > > Hi Cristi, > > > > > > On 0908, Cristian Ciocaltea wrote: > > > > Atomic transfers are required to properly power off a machine through > > > > an I2C controlled PMIC, such as the Actions Semi ATC260x series. > > > > > > > > System shutdown may happen with interrupts being disabled and, as a > > > > consequence, the kernel may hang if the driver does not support atomic > > > > transfers. > > > > > > > > This functionality is essentially implemented by polling the FIFO > > > > Status register until either Command Execute Completed or NACK Error > > > > bits are set. > > > > > > > > > > Thanks for the patch! I just have couple of minor comments and other > > > than that it looks good to me. > > > > > > > Signed-off-by: Cristian Ciocaltea > > > > --- > > > > Changes in v2: > > > > - Dropped unused return codes from owl_i2c_xfer_data(), per Mani's review > > > > - Rebased patch on v5.9-rc4 > > > > > > > > drivers/i2c/busses/i2c-owl.c | 78 ++++++++++++++++++++++++++---------- > > > > 1 file changed, 57 insertions(+), 21 deletions(-) > > > > > > > > diff --git a/drivers/i2c/busses/i2c-owl.c b/drivers/i2c/busses/i2c-owl.c > > > > index 672f1f239bd6..29605257831f 100644 > > > > --- a/drivers/i2c/busses/i2c-owl.c > > > > +++ b/drivers/i2c/busses/i2c-owl.c > > > > @@ -14,6 +14,7 @@ > > > > #include > > > > #include > > > > #include > > > > +#include > > > > #include > > > > #include > > > > > > > > @@ -76,6 +77,7 @@ > > > > #define OWL_I2C_FIFOCTL_TFR BIT(2) > > > > > > > > /* I2Cc_FIFOSTAT Bit Mask */ > > > > +#define OWL_I2C_FIFOSTAT_CECB BIT(0) > > > > #define OWL_I2C_FIFOSTAT_RNB BIT(1) > > > > #define OWL_I2C_FIFOSTAT_RFE BIT(2) > > > > #define OWL_I2C_FIFOSTAT_TFF BIT(5) > > > > @@ -83,7 +85,8 @@ > > > > #define OWL_I2C_FIFOSTAT_RFD GENMASK(15, 8) > > > > > > > > /* I2C bus timeout */ > > > > -#define OWL_I2C_TIMEOUT msecs_to_jiffies(4 * 1000) > > > > +#define OWL_I2C_TIMEOUT_MS (4 * 1000) > > > > +#define OWL_I2C_TIMEOUT msecs_to_jiffies(OWL_I2C_TIMEOUT_MS) > > > > > > > > #define OWL_I2C_MAX_RETRIES 50 > > > > > > > > @@ -161,29 +164,25 @@ static void owl_i2c_set_freq(struct owl_i2c_dev *i2c_dev) > > > > writel(OWL_I2C_DIV_FACTOR(val), i2c_dev->base + OWL_I2C_REG_CLKDIV); > > > > } > > > > > > > > -static irqreturn_t owl_i2c_interrupt(int irq, void *_dev) > > > > +static void owl_i2c_xfer_data(struct owl_i2c_dev *i2c_dev) > > > > { > > > > - struct owl_i2c_dev *i2c_dev = _dev; > > > > struct i2c_msg *msg = i2c_dev->msg; > > > > - unsigned long flags; > > > > unsigned int stat, fifostat; > > > > > > > > - spin_lock_irqsave(&i2c_dev->lock, flags); > > > > - > > > > i2c_dev->err = 0; > > > > > > > > /* Handle NACK from slave */ > > > > fifostat = readl(i2c_dev->base + OWL_I2C_REG_FIFOSTAT); > > > > if (fifostat & OWL_I2C_FIFOSTAT_RNB) { > > > > i2c_dev->err = -ENXIO; > > > > - goto stop; > > > > + return; > > > > } > > > > > > > > /* Handle bus error */ > > > > stat = readl(i2c_dev->base + OWL_I2C_REG_STAT); > > > > if (stat & OWL_I2C_STAT_BEB) { > > > > i2c_dev->err = -EIO; > > > > - goto stop; > > > > + return; > > > > } > > > > > > > > /* Handle FIFO read */ > > > > @@ -196,18 +195,28 @@ static irqreturn_t owl_i2c_interrupt(int irq, void *_dev) > > > > } else { > > > > /* Handle the remaining bytes which were not sent */ > > > > while (!(readl(i2c_dev->base + OWL_I2C_REG_FIFOSTAT) & > > > > - OWL_I2C_FIFOSTAT_TFF) && i2c_dev->msg_ptr < msg->len) { > > > > + OWL_I2C_FIFOSTAT_TFF) && i2c_dev->msg_ptr < msg->len) { > > > > > > Spurious change? > > > > I have just fixed a small indentation issue (removed extra space char > > in front of OWL_I2C...). I will revert it if you think it's not the right > > context for doing this (located ~10 lines bellow the previous edit). > > > > The extra space was there to align with the starting of 'readl', so please keep > it as it is. Right, sorry! I aligned it with the other 'readl' a few lines above and I missed the extra offset caused by the '!' operator. > > > > writel(msg->buf[i2c_dev->msg_ptr++], > > > > i2c_dev->base + OWL_I2C_REG_TXDAT); > > > > } > > > > } > > > > +} > > > > + > > > > +static irqreturn_t owl_i2c_interrupt(int irq, void *_dev) > > > > +{ > > > > + struct owl_i2c_dev *i2c_dev = _dev; > > > > + unsigned long flags; > > > > + > > > > + spin_lock_irqsave(&i2c_dev->lock, flags); > > > > + > > > > + owl_i2c_xfer_data(i2c_dev); > > > > > > > > -stop: > > > > /* Clear pending interrupts */ > > > > owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_STAT, > > > > OWL_I2C_STAT_IRQP, true); > > > > > > > > complete_all(&i2c_dev->msg_complete); > > > > + > > > > spin_unlock_irqrestore(&i2c_dev->lock, flags); > > > > > > > > return IRQ_HANDLED; > > > > @@ -235,8 +244,8 @@ static int owl_i2c_check_bus_busy(struct i2c_adapter *adap) > > > > return 0; > > > > } > > > > > > > > -static int owl_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, > > > > - int num) > > > > +static int owl_i2c_xfer_common(struct i2c_adapter *adap, struct i2c_msg *msgs, > > > > + int num, bool atomic) > > > > { > > > > struct owl_i2c_dev *i2c_dev = i2c_get_adapdata(adap); > > > > struct i2c_msg *msg; > > > > @@ -280,11 +289,12 @@ static int owl_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, > > > > goto err_exit; > > > > } > > > > > > > > - reinit_completion(&i2c_dev->msg_complete); > > > > + if (!atomic) > > > > + reinit_completion(&i2c_dev->msg_complete); > > > > > > > > - /* Enable I2C controller interrupt */ > > > > + /* Enable/disable I2C controller interrupt */ > > > > owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_CTL, > > > > - OWL_I2C_CTL_IRQE, true); > > > > + OWL_I2C_CTL_IRQE, !atomic); > > > > > > > > /* > > > > * Select: FIFO enable, Master mode, Stop enable, Data count enable, > > > > @@ -352,20 +362,33 @@ static int owl_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, > > > > > > > > spin_unlock_irqrestore(&i2c_dev->lock, flags); > > > > > > > > - time_left = wait_for_completion_timeout(&i2c_dev->msg_complete, > > > > - adap->timeout); > > > > + if (atomic) { > > > > + /* Wait for Command Execute Completed or NACK Error bits */ > > > > + ret = readl_poll_timeout_atomic(i2c_dev->base + OWL_I2C_REG_FIFOSTAT, > > > > + val, val & (OWL_I2C_FIFOSTAT_CECB | > > > > + OWL_I2C_FIFOSTAT_RNB), > > > > + 10, OWL_I2C_TIMEOUT_MS * 1000); > > > > + } else { > > > > + time_left = wait_for_completion_timeout(&i2c_dev->msg_complete, > > > > + adap->timeout); > > > > + if (!time_left) > > > > + ret = -ETIMEDOUT; > > > > + } > > > > > > > > spin_lock_irqsave(&i2c_dev->lock, flags); > > > > - if (time_left == 0) { > > > > + > > > > + if (ret) { > > > > dev_err(&adap->dev, "Transaction timed out\n"); > > > > /* Send stop condition and release the bus */ > > > > owl_i2c_update_reg(i2c_dev->base + OWL_I2C_REG_CTL, > > > > OWL_I2C_CTL_GBCC_STOP | OWL_I2C_CTL_RB, > > > > true); > > > > - ret = -ETIMEDOUT; > > > > goto err_exit; > > > > } > > > > > > > > + if (atomic) > > > > + owl_i2c_xfer_data(i2c_dev); > > > > > > You are not clearing the pending interrupts here. > > > > I assumed this is not needed for atomic contexts since the controller > > interrupt is disabled (please see the comment above: Enable/disable I2C > > controller interrupt). > > > > Otherwise I will simply move the clear pending interrupts code from > > owl_i2c_interrupt() to owl_i2c_xfer_data(). > > > > Hmm. My intention was to say that we are not clearing the error bits when they > happen but I misinterpreted that setting IRQP will take care of that but it > doesn't. > > So I think you should submit a patch which writes to RNB and BEB fields when > they are set (writing 1 will clear the interrupts) and ignore my previous > comment. Sure, I can handle this. I assume this should be a separate patch, to be applied before the current patch. Should I submit a patch series instead? Thanks, Cristi > Thanks, > Mani > > > > Thanks, > > > Mani > > > > > > > + > > > > ret = i2c_dev->err < 0 ? i2c_dev->err : num; > > > > > > > > err_exit: > > > > @@ -379,9 +402,22 @@ static int owl_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, > > > > return ret; > > > > } > > > > > > > > +static int owl_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, > > > > + int num) > > > > +{ > > > > + return owl_i2c_xfer_common(adap, msgs, num, false); > > > > +} > > > > + > > > > +static int owl_i2c_xfer_atomic(struct i2c_adapter *adap, > > > > + struct i2c_msg *msgs, int num) > > > > +{ > > > > + return owl_i2c_xfer_common(adap, msgs, num, true); > > > > +} > > > > + > > > > static const struct i2c_algorithm owl_i2c_algorithm = { > > > > - .master_xfer = owl_i2c_master_xfer, > > > > - .functionality = owl_i2c_func, > > > > + .master_xfer = owl_i2c_xfer, > > > > + .master_xfer_atomic = owl_i2c_xfer_atomic, > > > > + .functionality = owl_i2c_func, > > > > }; > > > > > > > > static const struct i2c_adapter_quirks owl_i2c_quirks = { > > > > -- > > > > 2.28.0 > > > > > > > > Kind regards, > > Cristi _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel