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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FAKE_REPLY_C,INCLUDES_PATCH,MAILING_LIST_MULTI, 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 0F8AAC3F2CD for ; Mon, 2 Mar 2020 22:25:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C858E24673 for ; Mon, 2 Mar 2020 22:25:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583187913; bh=CDhGcUfw787zc0VE8UcGNS8gfPoiSx89SWQtbWtTV2o=; h=Date:From:To:Cc:Subject:In-Reply-To:List-ID:From; b=k6jWk8dd9NX4RLMaPYRIG6pzmvz+ZeHTj64pzJfEVS9Wqqzc8T0VqjVwpj3PFMHjh gzhNvRP/4Ndse3i9PdDK4c9H5OOKnWCVO4gTHc0UDEcE0psyfdlYu/RMa/p5chcJXc quffyqb/nv/5RB2+8kj07a71vpoSRqI7wbDaUHVo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726752AbgCBWZN (ORCPT ); Mon, 2 Mar 2020 17:25:13 -0500 Received: from mail.kernel.org ([198.145.29.99]:38858 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726700AbgCBWZM (ORCPT ); Mon, 2 Mar 2020 17:25:12 -0500 Received: from localhost (mobile-166-175-186-165.mycingular.net [166.175.186.165]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B35312465D; Mon, 2 Mar 2020 22:25:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583187912; bh=CDhGcUfw787zc0VE8UcGNS8gfPoiSx89SWQtbWtTV2o=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=OAbDxpXPHgpYRpR7263JPUcp0o25FZX50iNMrdhav3mWgeA5PqZ8ZAVy4rDm+V98T tOdzW/rsq1ZvXHLVfHVlEiLAt/Pra7UNb0TqUeHyvpcM3MWEjiRPCi6NXnF47rs0R5 IpI1Vt9qmFrrr5wD6NMTGsTio7qssZLWD84tvWS4= Date: Mon, 2 Mar 2020 16:25:10 -0600 From: Bjorn Helgaas To: Jacob Keller Cc: linux-pci@vger.kernel.org, netdev@vger.kernel.org, Jeff Kirsher , QLogic-Storage-Upstream@cavium.com, Michael Chan Subject: Re: [PATCH 1/5] pci: introduce pci_get_dsn Message-ID: <20200302222510.GA172509@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200227223635.1021197-3-jacob.e.keller@intel.com> User-Agent: Mutt/1.12.2 (2019-09-21) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org PCI: Introduce pci_get_dsn() I learned this from "git log --oneline drivers/pci/pci.c". It looks like the other patches could benefit from this as well. On Thu, Feb 27, 2020 at 02:36:31PM -0800, Jacob Keller wrote: > Several device drivers read their Device Serial Number from the PCIe > extended config space. > > Introduce a new helper function, pci_get_dsn, which will read the > eight bytes of the DSN into the provided buffer. "pci_get_dsn()" > Signed-off-by: Jacob Keller > Cc: Bjorn Helgaas > Cc: Jeff Kirsher > Cc: QLogic-Storage-Upstream@cavium.com > Cc: Michael Chan > --- > drivers/pci/pci.c | 33 +++++++++++++++++++++++++++++++++ > include/linux/pci.h | 5 +++++ > 2 files changed, 38 insertions(+) > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index d828ca835a98..12d8101724d7 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -33,6 +33,7 @@ > #include > #include > #include > +#include > #include > #include "pci.h" > > @@ -557,6 +558,38 @@ int pci_find_ext_capability(struct pci_dev *dev, int cap) > } > EXPORT_SYMBOL_GPL(pci_find_ext_capability); > > +/** > + * pci_get_dsn - Read the 8-byte Device Serial Number > + * @dev: PCI device to query > + * @dsn: storage for the DSN. Must be at least 8 bytes > + * > + * Looks up the PCI_EXT_CAP_ID_DSN and reads the 8 bytes into the dsn storage. > + * Returns -EOPNOTSUPP if the device does not have the capability. > + */ > +int pci_get_dsn(struct pci_dev *dev, u8 dsn[]) > +{ > + u32 dword; > + int pos; > + > + > + pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DSN); > + if (!pos) > + return -EOPNOTSUPP; > + > + /* > + * The Device Serial Number is two dwords offset 4 bytes from the > + * capability position. > + */ > + pos += 4; > + pci_read_config_dword(dev, pos, &dword); > + put_unaligned_le32(dword, &dsn[0]); > + pci_read_config_dword(dev, pos + 4, &dword); > + put_unaligned_le32(dword, &dsn[4]); Since the serial number is a 64-bit value, can we just return a u64 and let the caller worry about any alignment and byte-order issues? This would be the only use of asm/unaligned.h in driver/pci, and I don't think DSN should be that special. I think it's OK if we return 0 if the device doesn't have a DSN capability. A DSN that actually contains a zero serial number would be dubious at best. > + return 0; > +} > +EXPORT_SYMBOL_GPL(pci_get_dsn); > + > static int __pci_find_next_ht_cap(struct pci_dev *dev, int pos, int ht_cap) > { > int rc, ttl = PCI_FIND_CAP_TTL; > diff --git a/include/linux/pci.h b/include/linux/pci.h > index 3840a541a9de..883562323df3 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -1045,6 +1045,8 @@ 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); > struct pci_bus *pci_find_next_bus(const struct pci_bus *from); > > +int pci_get_dsn(struct pci_dev *dev, u8 dsn[]); > + > struct pci_dev *pci_get_device(unsigned int vendor, unsigned int device, > struct pci_dev *from); > struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device, > @@ -1699,6 +1701,9 @@ static inline int pci_find_next_capability(struct pci_dev *dev, u8 post, > static inline int pci_find_ext_capability(struct pci_dev *dev, int cap) > { return 0; } > > +static inline int pci_get_dsn(struct pci_dev *dev, u8 dsn[]) > +{ return -EOPNOTSUPP; } > + > /* Power management related routines */ > static inline int pci_save_state(struct pci_dev *dev) { return 0; } > static inline void pci_restore_state(struct pci_dev *dev) { } > -- > 2.25.0.368.g28a2d05eebfb >