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=-15.4 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 5AECBC433E0 for ; Wed, 3 Feb 2021 22:57:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2786364F6A for ; Wed, 3 Feb 2021 22:57:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232772AbhBCW4r (ORCPT ); Wed, 3 Feb 2021 17:56:47 -0500 Received: from mga12.intel.com ([192.55.52.136]:21001 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231200AbhBCW4p (ORCPT ); Wed, 3 Feb 2021 17:56:45 -0500 IronPort-SDR: ZY4NReiVX9vdo2XyYYfourZykZMdJX6spHOGODgq1T+UDDxkcLclZhiQm7k/vwnMzrO9MH++F9 NchuZRJaN+6w== X-IronPort-AV: E=McAfee;i="6000,8403,9884"; a="160297869" X-IronPort-AV: E=Sophos;i="5.79,399,1602572400"; d="scan'208";a="160297869" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Feb 2021 14:56:01 -0800 IronPort-SDR: JOPgaZF3v7otJF/hnTxSDFVPlM77qOJU1zNT/0F10SNmlw6iHGEqkmh5wrv+26NV0VFs5FMk5D NhzDkM4Q7FAQ== X-IronPort-AV: E=Sophos;i="5.79,399,1602572400"; d="scan'208";a="396841756" Received: from rhweight-mobl2.amr.corp.intel.com (HELO [10.0.2.4]) ([10.212.187.111]) by orsmga007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Feb 2021 14:56:00 -0800 Subject: Re: [PATCH v3 1/1] fpga: dfl: afu: harden port enable logic To: "Wu, Hao" , "mdf@kernel.org" , "linux-fpga@vger.kernel.org" , "linux-kernel@vger.kernel.org" Cc: "trix@redhat.com" , "lgoncalv@redhat.com" , "Xu, Yilun" , "Gerlach, Matthew" References: <20210202230631.198950-1-russell.h.weight@intel.com> From: Russ Weight Message-ID: <7ab15adf-81b5-f1ba-ef02-c31701592e4c@intel.com> Date: Wed, 3 Feb 2021 14:55:58 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2/3/21 1:01 AM, Wu, Hao wrote: >> Subject: [PATCH v3 1/1] fpga: dfl: afu: harden port enable logic >> >> Port enable is not complete until ACK = 0. Change >> __afu_port_enable() to guarantee that the enable process >> is complete by polling for ACK == 0. >> >> Signed-off-by: Russ Weight >> --- >> v3: >> - afu_port_err_clear() changed to prioritize port_enable failure over >> other a detected mismatch in port errors. >> - reorganized code in port_reset() to be more readable. >> v2: >> - Fixed typo in commit message >> --- >> drivers/fpga/dfl-afu-error.c | 8 ++++---- >> drivers/fpga/dfl-afu-main.c | 31 ++++++++++++++++++++++--------- >> drivers/fpga/dfl-afu.h | 2 +- >> 3 files changed, 27 insertions(+), 14 deletions(-) >> >> diff --git a/drivers/fpga/dfl-afu-error.c b/drivers/fpga/dfl-afu-error.c >> index c4691187cca9..2ced610059cc 100644 >> --- a/drivers/fpga/dfl-afu-error.c >> +++ b/drivers/fpga/dfl-afu-error.c >> @@ -52,7 +52,7 @@ static int afu_port_err_clear(struct device *dev, u64 err) >> struct dfl_feature_platform_data *pdata = dev_get_platdata(dev); >> struct platform_device *pdev = to_platform_device(dev); >> void __iomem *base_err, *base_hdr; >> -int ret = -EBUSY; >> +int enable_ret = 0, ret = -EBUSY; >> u64 v; >> >> base_err = dfl_get_feature_ioaddr_by_id(dev, >> PORT_FEATURE_ID_ERROR); >> @@ -102,12 +102,12 @@ static int afu_port_err_clear(struct device *dev, u64 >> err) >> /* Clear mask */ >> __afu_port_err_mask(dev, false); >> >> -/* Enable the Port by clear the reset */ >> -__afu_port_enable(pdev); >> +/* Enable the Port by clearing the reset */ >> +enable_ret = __afu_port_enable(pdev); >> >> done: >> mutex_unlock(&pdata->lock); >> -return ret; >> +return enable_ret ? enable_ret : ret; > Maybe we should add some error message to notify user, there are more errors happened, > as some ret value is not returned. It is the -EINVAL error case that would get lost if there was a double error. This error indicates that the value written to sysfs by the user does not correspond to the current port errors. This is not a hardware error, and could even be a user error. Do you think a warning in the error log is needed here? > >> } >> >> static ssize_t errors_show(struct device *dev, struct device_attribute *attr, >> diff --git a/drivers/fpga/dfl-afu-main.c b/drivers/fpga/dfl-afu-main.c >> index 753cda4b2568..729eb306062e 100644 >> --- a/drivers/fpga/dfl-afu-main.c >> +++ b/drivers/fpga/dfl-afu-main.c >> @@ -21,6 +21,9 @@ >> >> #include "dfl-afu.h" >> >> +#define RST_POLL_INVL 10 /* us */ >> +#define RST_POLL_TIMEOUT 1000 /* us */ >> + >> /** >> * __afu_port_enable - enable a port by clear reset >> * @pdev: port platform device. >> @@ -32,7 +35,7 @@ >> * >> * The caller needs to hold lock for protection. >> */ >> -void __afu_port_enable(struct platform_device *pdev) >> +int __afu_port_enable(struct platform_device *pdev) >> { >> struct dfl_feature_platform_data *pdata = dev_get_platdata(&pdev- >>> dev); >> void __iomem *base; >> @@ -41,7 +44,7 @@ void __afu_port_enable(struct platform_device *pdev) >> WARN_ON(!pdata->disable_count); >> >> if (--pdata->disable_count != 0) >> -return; >> +return 0; >> >> base = dfl_get_feature_ioaddr_by_id(&pdev->dev, >> PORT_FEATURE_ID_HEADER); >> >> @@ -49,10 +52,20 @@ void __afu_port_enable(struct platform_device *pdev) >> v = readq(base + PORT_HDR_CTRL); >> v &= ~PORT_CTRL_SFTRST; >> writeq(v, base + PORT_HDR_CTRL); >> -} >> >> -#define RST_POLL_INVL 10 /* us */ >> -#define RST_POLL_TIMEOUT 1000 /* us */ >> +/* >> + * HW clears the ack bit to indicate that the port is fully out >> + * of reset. >> + */ >> +if (readq_poll_timeout(base + PORT_HDR_CTRL, v, >> + !(v & PORT_CTRL_SFTRST_ACK), >> + RST_POLL_INVL, RST_POLL_TIMEOUT)) { >> +dev_err(&pdev->dev, "timeout, failure to enable device\n"); > Maybe we can change dev_err message in port disable to "disable device" as well. : ) Thank you. I'll submit a new version of the patch with this fix. - Russ > > Hao > >> +return -ETIMEDOUT; >> +} >> + >> +return 0; >> +} >> >> /** >> * __afu_port_disable - disable a port by hold reset >> @@ -111,9 +124,9 @@ static int __port_reset(struct platform_device *pdev) >> >> ret = __afu_port_disable(pdev); >> if (!ret) >> -__afu_port_enable(pdev); >> +return ret; >> >> -return ret; >> +return __afu_port_enable(pdev); >> } >> >> static int port_reset(struct platform_device *pdev) >> @@ -872,11 +885,11 @@ static int afu_dev_destroy(struct platform_device >> *pdev) >> static int port_enable_set(struct platform_device *pdev, bool enable) >> { >> struct dfl_feature_platform_data *pdata = dev_get_platdata(&pdev- >>> dev); >> -int ret = 0; >> +int ret; >> >> mutex_lock(&pdata->lock); >> if (enable) >> -__afu_port_enable(pdev); >> +ret = __afu_port_enable(pdev); >> else >> ret = __afu_port_disable(pdev); >> mutex_unlock(&pdata->lock); >> diff --git a/drivers/fpga/dfl-afu.h b/drivers/fpga/dfl-afu.h >> index 576e94960086..e5020e2b1f3d 100644 >> --- a/drivers/fpga/dfl-afu.h >> +++ b/drivers/fpga/dfl-afu.h >> @@ -80,7 +80,7 @@ struct dfl_afu { >> }; >> >> /* hold pdata->lock when call __afu_port_enable/disable */ >> -void __afu_port_enable(struct platform_device *pdev); >> +int __afu_port_enable(struct platform_device *pdev); >> int __afu_port_disable(struct platform_device *pdev); >> >> void afu_mmio_region_init(struct dfl_feature_platform_data *pdata); >> -- >> 2.25.1