From patchwork Tue Mar 3 02:25:00 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jacob Keller X-Patchwork-Id: 11417101 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 731EF930 for ; Tue, 3 Mar 2020 02:25:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5BF7A217F4 for ; Tue, 3 Mar 2020 02:25:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727085AbgCCCZT (ORCPT ); Mon, 2 Mar 2020 21:25:19 -0500 Received: from mga14.intel.com ([192.55.52.115]:54186 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727041AbgCCCZI (ORCPT ); Mon, 2 Mar 2020 21:25:08 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 02 Mar 2020 18:25:08 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,509,1574150400"; d="scan'208";a="233605686" Received: from jekeller-desk.amr.corp.intel.com (HELO jekeller-desk.jekeller.internal) ([10.166.244.172]) by fmsmga008.fm.intel.com with ESMTP; 02 Mar 2020 18:25:07 -0800 From: Jacob Keller To: linux-pci@vger.kernel.org, netdev@vger.kernel.org, Bjorn Helgaas Cc: Jakub Kicinski , David Miller , Jacob Keller , Jeff Kirsher , Michael Chan Subject: [PATCH v2 1/6] PCI: Introduce pci_get_dsn Date: Mon, 2 Mar 2020 18:25:00 -0800 Message-Id: <20200303022506.1792776-2-jacob.e.keller@intel.com> X-Mailer: git-send-email 2.25.0.368.g28a2d05eebfb In-Reply-To: <20200303022506.1792776-1-jacob.e.keller@intel.com> References: <20200303022506.1792776-1-jacob.e.keller@intel.com> MIME-Version: 1.0 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Several device drivers read their Device Serial Number from the PCIe extended config space. Introduce a new helper function, pci_get_dsn(). This function reads the eight bytes of the DSN and returns them as a u64. If the capability does not exist for the device, the function returns 0. Signed-off-by: Jacob Keller Cc: Bjorn Helgaas Cc: Jeff Kirsher Cc: Michael Chan Acked-by: Bjorn Helgaas --- drivers/pci/pci.c | 34 ++++++++++++++++++++++++++++++++++ include/linux/pci.h | 5 +++++ 2 files changed, 39 insertions(+) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index d828ca835a98..03f50e706c0d 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -557,6 +557,40 @@ int pci_find_ext_capability(struct pci_dev *dev, int cap) } EXPORT_SYMBOL_GPL(pci_find_ext_capability); +/** + * pci_get_dsn - Read and return the 8-byte Device Serial Number + * @dev: PCI device to query + * + * Looks up the PCI_EXT_CAP_ID_DSN and reads the 8 bytes of the Device Serial + * Number. + * + * Returns the DSN, or zero if the capability does not exist. + */ +u64 pci_get_dsn(struct pci_dev *dev) +{ + u32 dword; + u64 dsn; + int pos; + + pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DSN); + if (!pos) + return 0; + + /* + * The Device Serial Number is two dwords offset 4 bytes from the + * capability position. The specification says that the first dword is + * the lower half, and the second dword is the upper half. + */ + pos += 4; + pci_read_config_dword(dev, pos, &dword); + dsn = (u64)dword; + pci_read_config_dword(dev, pos + 4, &dword); + dsn |= ((u64)dword) << 32; + + return dsn; +} +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..d92cf2da1ae1 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); +u64 pci_get_dsn(struct pci_dev *dev); + 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 u64 pci_get_dsn(struct pci_dev *dev) +{ return 0; } + /* 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) { }