From patchwork Tue Jul 5 15:49:31 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ira Weiny X-Patchwork-Id: 12906781 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 457AEC43334 for ; Tue, 5 Jul 2022 15:51:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232951AbiGEPvp (ORCPT ); Tue, 5 Jul 2022 11:51:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46718 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232195AbiGEPvG (ORCPT ); Tue, 5 Jul 2022 11:51:06 -0400 Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9C0911928E; Tue, 5 Jul 2022 08:50:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1657036211; x=1688572211; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=KHO4l4f5twVCRTpiTRrOo5KIdLqw6qldFhvobbtx6xE=; b=k3ZCWoDa/3qKtD26RyJvsOYpx7uY/j0eHN3kpSQ17jwQ659iFfbt6Czo DpFSGFhke3WpRE9jTBOHt5WTM5OSq9bsPc0J6fzwhnZjTonAq6kZZChV/ 9KhLPNy2cjMqWfBtB5DYB+jsIkPwZcjcuiCNP6rGMZubAu2A1zU9sSN2i utyrgbWy79HPZO5T+pZ6gAq1coePr+PwPJBlqebGnOiYwflWZj5yZxxcl fWIZyat7+yAZFjAjawgNnYXdXJVhz01mUMrGpfsD0azVDZnNmPohVb/WW mxlYQOW/0mUvDRDfRUYHVx0F2UlXVycDB8Bbv2SpWCd5xO/hK3RI/Z4S8 g==; X-IronPort-AV: E=McAfee;i="6400,9594,10398"; a="272169460" X-IronPort-AV: E=Sophos;i="5.92,247,1650956400"; d="scan'208";a="272169460" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Jul 2022 08:50:11 -0700 X-IronPort-AV: E=Sophos;i="5.92,247,1650956400"; d="scan'208";a="660600771" Received: from amangla-mobl.amr.corp.intel.com (HELO localhost) ([10.255.0.184]) by fmsmga004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Jul 2022 08:50:08 -0700 From: ira.weiny@intel.com To: Dan Williams , Bjorn Helgaas , Jonathan Cameron Cc: Ira Weiny , Ben Widawsky , Alison Schofield , Lukas Wunner , Vishal Verma , Dave Jiang , linux-kernel@vger.kernel.org, linux-cxl@vger.kernel.org, linux-pci@vger.kernel.org Subject: [PATCH V13 8/9] cxl/port: Retry reading CDAT on failure Date: Tue, 5 Jul 2022 08:49:31 -0700 Message-Id: <20220705154932.2141021-9-ira.weiny@intel.com> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20220705154932.2141021-1-ira.weiny@intel.com> References: <20220705154932.2141021-1-ira.weiny@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-cxl@vger.kernel.org From: Ira Weiny The CDAT read may fail for a number of reasons but mainly it is possible to get different parts of a valid state. The checksum in the CDAT table protects against this. Now that the cdat data is validated, issue a retry if the CDAT read fails. For now 5 retries are implemented. Reviewed-by: Ben Widawsky Reviewed-by: Alison Schofield Signed-off-by: Ira Weiny --- Changes from V12 Jonathan: Standardize on 'rc' for return code Don't set rc unnecessarily Changes from V10 Pick up review tag and fix commit message Changes from V9 Alison Schofield/Davidlohr Bueso Print debug on each iteration and error only after failure Changes from V8 Move code to cxl/core/pci.c Changes from V6 Move to pci.c Fix retries count Change to 5 retries Changes from V5: New patch -- easy to push off or drop. --- drivers/cxl/core/pci.c | 39 +++++++++++++++++++++++++++++---------- 1 file changed, 29 insertions(+), 10 deletions(-) diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c index 0a1620c302e1..0853885c5767 100644 --- a/drivers/cxl/core/pci.c +++ b/drivers/cxl/core/pci.c @@ -623,13 +623,7 @@ static int cxl_cdat_read_table(struct device *dev, return 0; } -/** - * read_cdat_data - Read the CDAT data on this port - * @port: Port to read data from - * - * This call will sleep waiting for responses from the DOE mailbox. - */ -void read_cdat_data(struct cxl_port *port) +static int __read_cdat_data(struct cxl_port *port) { static struct pci_doe_mb *cdat_mb; struct device *dev = &port->dev; @@ -640,19 +634,19 @@ void read_cdat_data(struct cxl_port *port) cdat_mb = find_cdat_mb(uport); if (!cdat_mb) { dev_dbg(dev, "No CDAT mailbox\n"); - return; + return -EIO; } port->cdat_sup = true; if (cxl_cdat_get_length(dev, cdat_mb, &cdat_length)) { dev_dbg(dev, "No CDAT length\n"); - return; + return -EIO; } port->cdat.table = devm_kzalloc(dev, cdat_length, GFP_KERNEL); if (!port->cdat.table) - return; + return -ENOMEM; port->cdat.length = cdat_length; rc = cxl_cdat_read_table(dev, cdat_mb, &port->cdat); @@ -663,5 +657,30 @@ void read_cdat_data(struct cxl_port *port) port->cdat.length = 0; dev_err(dev, "CDAT data read error\n"); } + + return rc; +} + +/** + * read_cdat_data - Read the CDAT data on this port + * @port: Port to read data from + * + * This call will sleep waiting for responses from the DOE mailbox. + */ +void read_cdat_data(struct cxl_port *port) +{ + int retries = 5; + int rc; + + while (retries--) { + rc = __read_cdat_data(port); + if (!rc) + return; + dev_dbg(&port->dev, + "CDAT data read error rc=%d (retries %d)\n", + rc, retries); + } + dev_err(&port->dev, "CDAT data read failed after %d retries\n", + retries); } EXPORT_SYMBOL_NS_GPL(read_cdat_data, CXL);