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

[Gu Zheng <guz.fnst@cn.fujitsu.com>]

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>

> 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);