Messages in this thread Patch in this message | | | Date | Thu, 11 Jul 2013 05:51:46 -0400 | From | Don Dutile <> | Subject | Re: [PATCH -v2 1/3] PCI: introduce PCIe Device Serial Number Capability support |
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On 07/11/2013 05:43 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<wangyijing@huawei.com> > --- > drivers/pci/pci.c | 27 +++++++++++++++++++++++++++ > drivers/pci/probe.c | 2 ++ > include/linux/pci.h | 3 +++ > 3 files changed, 32 insertions(+), 0 deletions(-) > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index e37fea6..2e855b5 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -2048,6 +2048,33 @@ void pci_free_cap_save_buffers(struct pci_dev *dev) > } > > /** > + * pci_device_serial_number - get device serial number > + * @dev: the PCI device > + * > + * return the device serial number if device support, > + * otherwise return 0. > + */ > +u64 pci_device_serial_number(struct pci_dev *dev) See comment below: void pci_device_serial_number(struct pci_dev *dev)
> +{ > + int pos; > + u64 sn; > + u32 lo, hi; > + > + if (!pci_is_pcie(dev)) > + return 0; > + See comment below: if (!pci_is_pcie(dev)) { dev->sn = 0; return; } > + pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DSN); > + if (!pos) > + return 0; > + > + pci_read_config_dword(dev, pos + 4,&lo); > + pci_read_config_dword(dev, pos + 8,&hi); > + sn = ((u64)hi<< 32) | lo; See comment below: dev->sn = ((u64)hi<< 32) | lo; return; > + return sn; > +} > +EXPORT_SYMBOL(pci_device_serial_number); > + > +/** > * pci_configure_ari - enable or disable ARI forwarding > * @dev: the PCI device > * > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > index 46ada5c..c4c1a2b 100644 > --- a/drivers/pci/probe.c > +++ b/drivers/pci/probe.c > @@ -1322,6 +1322,8 @@ static void pci_init_capabilities(struct pci_dev *dev) > /* Power Management */ > pci_pm_init(dev); > > + dev->sn = pci_device_serial_number(dev); > + Finally, 'the comment below': I know you were following Bjorn's suggestion, which I thought was an improvement, but why not do above assignment in pci_device_serial_number() ? See above.... - Don
> /* Vital Product Data */ > pci_vpd_pci22_init(dev); > > diff --git a/include/linux/pci.h b/include/linux/pci.h > index 0fd1f15..10d190b 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 +996,8 @@ 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); > > +u64 pci_device_serial_number(struct pci_dev *dev); > + > /* 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);
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