Re: [PATCH 1/2] PCI: introduce PCIe Device Serial NUmber Capability support

[Yijing Wang <wangyijing@huawei.com>]

On 2013/7/9 16:09, Gu Zheng wrote:
> On 07/09/2013 03:55 PM, 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.
> 
> Nice idea!
> 
> Regards,
> Gu
> 
>>
>> Signed-off-by: Yijing Wang <wangyijing@huawei.com>
> 
> 
> Reviewed-by: Gu Zheng <guz.fnst@cn.fujitsu.com>

Thanks very much!

Yijing.



> 
>> Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
>> Cc: Oliver Neukum <oneukum@suse.de>
>> Cc: Paul Bolle <pebolle@tiscali.nl>
>> Cc: Gu Zheng <guz.fnst@cn.fujitsu.com>
>> 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)
>> +{
>> +	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);
>> +
>>  	/* 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);
> 
> 
> 
> .
> 


-- 
Thanks!
Yijing