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=-11.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 D388FC00A89 for ; Mon, 2 Nov 2020 15:50:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A825B206E5 for ; Mon, 2 Nov 2020 15:50:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726070AbgKBPuo (ORCPT ); Mon, 2 Nov 2020 10:50:44 -0500 Received: from mga05.intel.com ([192.55.52.43]:45943 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725837AbgKBPuo (ORCPT ); Mon, 2 Nov 2020 10:50:44 -0500 IronPort-SDR: uoN3wg8N2yGgffBLUPMx4yUgxETjK2P5uldLZ+MCcrJf5zldeSWENHZWeVhUo5oBrsfMOa69l9 fVU0/XzR0ptw== X-IronPort-AV: E=McAfee;i="6000,8403,9793"; a="253612834" X-IronPort-AV: E=Sophos;i="5.77,445,1596524400"; d="scan'208";a="253612834" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Nov 2020 07:50:43 -0800 IronPort-SDR: SiUGt6sTq+UirrfrqKaS73FIspwj0fSjeGyTBARGmipB8jNkWP/OeVVlr89k6dAMwixeR8DnQC Z4EAe/4e2yuQ== X-IronPort-AV: E=Sophos;i="5.77,445,1596524400"; d="scan'208";a="336205894" Received: from djiang5-mobl1.amr.corp.intel.com (HELO [10.251.132.252]) ([10.251.132.252]) by orsmga002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Nov 2020 07:50:42 -0800 Subject: Re: [PATCH] PCI: add helper function to find DVSEC To: Randy Dunlap , bhelgaas@google.com Cc: linux-pci@vger.kernel.org, david.e.box@intel.com, sean.v.kelly@intel.com, ashok.raj@intel.com References: <160409768616.919324.13994867117217584719.stgit@djiang5-desk3.ch.intel.com> From: Dave Jiang Message-ID: Date: Mon, 2 Nov 2020 08:50:39 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.12.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On 10/30/2020 10:35 PM, Randy Dunlap wrote: > On 10/30/20 3:42 PM, Dave Jiang wrote: >> Add function that searches for DVSEC and returns the offset in PCI >> configuration space for the interested DVSEC capability. >> >> Signed-off-by: Dave Jiang >> Reviewed-by: Ashok Raj >> --- >> >> The patch has dependency on David Box’s dvsec definition patch: >> https://lore.kernel.org/linux-pci/bc5f059c5bae957daebde699945c80808286bf45.camel@linux.intel.com/T/#m1d0dc12e3b2c739e2c37106a45f325bb8f001774 >> >> drivers/pci/pci.c | 30 ++++++++++++++++++++++++++++++ >> include/linux/pci.h | 3 +++ >> 2 files changed, 33 insertions(+) >> >> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c >> index 6d4d5a2f923d..49e57b831509 100644 >> --- a/drivers/pci/pci.c >> +++ b/drivers/pci/pci.c >> @@ -589,6 +589,36 @@ int pci_find_ext_capability(struct pci_dev *dev, int cap) >> } >> EXPORT_SYMBOL_GPL(pci_find_ext_capability); >> >> +/** >> + * pci_find_dvsec - return position of DVSEC with provided vendor and DVSEC ID >> + * @dev: the PCI device >> + * @vendor: vendor for the DVSEC >> + * @id: the DVSEC capibility ID > > capability > >> + * >> + * Return the offset of DVSEC on success or -ENOTSUPP if not found > > * Return: the offset of DVSEC on success or -ENOTSUPP if not found > >> + */ >> +int pci_find_dvsec(struct pci_dev *dev, u16 vendor, u16 id) >> +{ >> + u16 dev_vendor, dev_id; >> + int pos; >> + >> + pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DVSEC); >> + if (!pos) >> + return -ENOTSUPP; >> + >> + while (pos) { >> + pci_read_config_word(dev, pos + PCI_DVSEC_HEADER1, &dev_vendor); >> + pci_read_config_word(dev, pos + PCI_DVSEC_HEADER2, &dev_id); >> + if (dev_vendor == vendor && dev_id == id) >> + return pos; >> + >> + pos = pci_find_next_ext_capability(dev, pos, PCI_EXT_CAP_ID_DVSEC); >> + } >> + >> + return -ENOTSUPP; >> +} >> +EXPORT_SYMBOL_GPL(pci_find_dvsec); >> + >> /** >> * pci_get_dsn - Read and return the 8-byte Device Serial Number >> * @dev: PCI device to query >> diff --git a/include/linux/pci.h b/include/linux/pci.h >> index 22207a79762c..6c692d32c82a 100644 >> --- a/include/linux/pci.h >> +++ b/include/linux/pci.h >> @@ -1069,6 +1069,7 @@ int pci_find_ext_capability(struct pci_dev *dev, int cap); >> int pci_find_next_ext_capability(struct pci_dev *dev, int pos, int cap); >> int pci_find_ht_capability(struct pci_dev *dev, int ht_cap); >> int pci_find_next_ht_capability(struct pci_dev *dev, int pos, int ht_cap); >> +int pci_find_dvsec(struct pci_dev *dev, u16 vendor, u16 id); >> struct pci_bus *pci_find_next_bus(const struct pci_bus *from); >> >> u64 pci_get_dsn(struct pci_dev *dev); >> @@ -1726,6 +1727,8 @@ static inline int pci_find_next_capability(struct pci_dev *dev, u8 post, >> { return 0; } >> static inline int pci_find_ext_capability(struct pci_dev *dev, int cap) >> { return 0; } >> +static inline int pci_find_dvsec(struct pci_dev *dev, u16 vendor, u16 id) >> +{ return 0; } > > Why shouldn't this return -ENOTSUPP instead of 0? Actually looking at the other find cap functions. Should I be returning 0 for all failures? > >> >> static inline u64 pci_get_dsn(struct pci_dev *dev) >> { return 0; } >> >> >