Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754829Ab3GJV6O (ORCPT ); Wed, 10 Jul 2013 17:58:14 -0400 Received: from mail-oa0-f42.google.com ([209.85.219.42]:53194 "EHLO mail-oa0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754292Ab3GJV6M (ORCPT ); Wed, 10 Jul 2013 17:58:12 -0400 MIME-Version: 1.0 In-Reply-To: <1373356545-45944-1-git-send-email-wangyijing@huawei.com> References: <1373356545-45944-1-git-send-email-wangyijing@huawei.com> From: Bjorn Helgaas Date: Wed, 10 Jul 2013 15:57:51 -0600 Message-ID: Subject: Re: [PATCH 1/2] PCI: introduce PCIe Device Serial NUmber Capability support To: Yijing Wang Cc: "linux-kernel@vger.kernel.org" , "linux-pci@vger.kernel.org" , Rafael , Hanjun Guo , Jiang Liu , Oliver Neukum , Paul Bolle , Gu Zheng Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4462 Lines: 136 On Tue, Jul 9, 2013 at 1:55 AM, Yijing Wang wrote: > Introduce PCIe Ext Capability Device Serial Number support, > so we can use the unique device serial number to identify > the physical device. During system suspend, if the PCIe > device was removed and inserted a new same device, after > system resume there is no good way to identify it, maybe > Device Serial Number is a good choice if device support. > > Signed-off-by: Yijing Wang > Cc: "Rafael J. Wysocki" > Cc: Oliver Neukum > Cc: Paul Bolle > Cc: Gu Zheng > Cc: linux-pci@vger.kernel.org > --- > drivers/pci/pci.c | 33 +++++++++++++++++++++++++++++++++ > drivers/pci/pci.h | 1 + > drivers/pci/probe.c | 3 +++ > include/linux/pci.h | 4 ++++ > 4 files changed, 41 insertions(+), 0 deletions(-) > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index e37fea6..d08df2b 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -2048,6 +2048,39 @@ void pci_free_cap_save_buffers(struct pci_dev *dev) > } > > /** > + * pci_get_dsn - get device serial number > + * @dev: the PCI device > + * @sn: saved device serial number > + */ > +void pci_get_dsn(struct pci_dev *dev, u64 *sn) How about: u64 pci_device_serial_number(struct pci_dev *dev) "get" suggests reference counting, which isn't happening here. And why pass a pointer to a return value when we can just as easily return it directly? > +{ > + int pos; > + u32 lo, hi; > + > + if (!pci_is_pcie(dev)) > + goto out; > + > + pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DSN); > + if (!pos) > + goto out; > + > + pci_read_config_dword(dev, pos + 4, &lo); > + pci_read_config_dword(dev, pos + 8, &hi); > + *sn = ((u64)hi << 32) | lo; > + return; > + > +out: > + *sn = 0; > + return; > +} > +EXPORT_SYMBOL(pci_get_dsn); > + > +void pci_dsn_init(struct pci_dev *dev) > +{ > + return pci_get_dsn(dev, &dev->sn); > +} > + > +/** > * pci_configure_ari - enable or disable ARI forwarding > * @dev: the PCI device > * > diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h > index 68678ed..f626006 100644 > --- a/drivers/pci/pci.h > +++ b/drivers/pci/pci.h > @@ -202,6 +202,7 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type, > struct resource *res, unsigned int reg); > int pci_resource_bar(struct pci_dev *dev, int resno, enum pci_bar_type *type); > void pci_configure_ari(struct pci_dev *dev); > +void pci_dsn_init(struct pci_dev *dev); > > /** > * pci_ari_enabled - query ARI forwarding status > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > index 46ada5c..d4c6e7e 100644 > --- a/drivers/pci/probe.c > +++ b/drivers/pci/probe.c > @@ -1322,6 +1322,9 @@ static void pci_init_capabilities(struct pci_dev *dev) > /* Power Management */ > pci_pm_init(dev); > > + /* Device Serial Number */ > + pci_dsn_init(dev); dev->sn = pci_serial_number(dev); Obvious, no comment or wrapper function needed. > + > /* Vital Product Data */ > pci_vpd_pci22_init(dev); > > diff --git a/include/linux/pci.h b/include/linux/pci.h > index 0fd1f15..59cd205 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -342,6 +342,7 @@ struct pci_dev { > struct list_head msi_list; > struct kset *msi_kset; > #endif > + u64 sn; /* device serieal number, 0 if not support */ > struct pci_vpd *vpd; > #ifdef CONFIG_PCI_ATS > union { > @@ -995,6 +996,9 @@ ssize_t pci_read_vpd(struct pci_dev *dev, loff_t pos, size_t count, void *buf); > ssize_t pci_write_vpd(struct pci_dev *dev, loff_t pos, size_t count, const void *buf); > int pci_vpd_truncate(struct pci_dev *dev, size_t size); > > +/* Device Serial Number */ > +void pci_get_dsn(struct pci_dev *dev, u64 *sn); > + > /* Helper functions for low-level code (drivers/pci/setup-[bus,res].c) */ > resource_size_t pcibios_retrieve_fw_addr(struct pci_dev *dev, int idx); > void pci_bus_assign_resources(const struct pci_bus *bus); > -- > 1.7.1 > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/