Re: [PATCH v9 1/5] ethdev: add firmware version get

["Yang, Qiming" <qiming.yang@intel.com>]

Hi, Andrew 
> > diff --git a/lib/librte_ether/rte_ethdev.c
> > b/lib/librte_ether/rte_ethdev.c index 917557a..89cffcf 100644
> > --- a/lib/librte_ether/rte_ethdev.c
> > +++ b/lib/librte_ether/rte_ethdev.c
> > @@ -1588,6 +1588,18 @@
> rte_eth_dev_set_rx_queue_stats_mapping(uint8_t port_id, uint16_t
> rx_queue_id,
> >   			STAT_QMAP_RX);
> >   }
> >
> > +int
> > +rte_eth_dev_fw_version_get(uint8_t port_id, char *fw_version, size_t
> > +fw_size) {
> > +	struct rte_eth_dev *dev;
> > +
> > +	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
> > +	dev = &rte_eth_devices[port_id];
> > +
> > +	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->fw_version_get, -
> ENOTSUP);
> > +	return (*dev->dev_ops->fw_version_get)(dev, fw_version, fw_size);
> 
> I think it would be good to handle difference from snprintf() behaviour here
> and specify that fw_version_get callback has exactly snprintf()-like return
> value.
> It would allow to avoid
> duplicated code in all drivers (adding 1 for terminating null, conversion of
> success value to 0).

But I think it would be better to just keep the way it is. If I handle snpritf() behavior here,
may the function rte_eth_dev_fw_version_get and ops fw_version_get will have different 
definition of return value.

> Also I think warning about insufficient space is not required. It could be
> intentional to call the first time with 0 (or some small) space to get required
> space to be (re)allocated.
> May be debug level message would be useful.

Good advice, when call this function with 0, this function will become a API to get
firmware version size. I think we can remove the warning message here.

> 
> > +}
> > +
> >   void
> >   rte_eth_dev_info_get(uint8_t port_id, struct rte_eth_dev_info
> *dev_info)
> >   {
> > diff --git a/lib/librte_ether/rte_ethdev.h
> > b/lib/librte_ether/rte_ethdev.h index ded43d7..37a55ef 100644
> > --- a/lib/librte_ether/rte_ethdev.h
> > +++ b/lib/librte_ether/rte_ethdev.h
> > @@ -1177,6 +1177,10 @@ typedef uint32_t
> (*eth_rx_queue_count_t)(struct rte_eth_dev *dev,
> >   typedef int (*eth_rx_descriptor_done_t)(void *rxq, uint16_t offset);
> >   /**< @internal Check DD bit of specific RX descriptor */
> >
> > +typedef int (*eth_fw_version_get_t)(struct rte_eth_dev *dev,
> > +				     char *fw_version, size_t fw_size); /**<
> @internal Get
> > +firmware information of an Ethernet device. */
> > +
> 
> If we finally have different return value for
> rte_eth_dev_fw_version_get() and here,
> it would be useful to highlight it here.

If I keep the handle of snprintf() return value in drivers, they will not have different
return here, so the highlight is not necessary.

> >   typedef void (*eth_rxq_info_get_t)(struct rte_eth_dev *dev,
> >   	uint16_t rx_queue_id, struct rte_eth_rxq_info *qinfo);
> >
> > @@ -1459,6 +1463,7 @@ struct eth_dev_ops {
> >   	eth_dev_infos_get_t        dev_infos_get; /**< Get device info. */
> >   	eth_rxq_info_get_t         rxq_info_get; /**< retrieve RX queue
> information. */
> >   	eth_txq_info_get_t         txq_info_get; /**< retrieve TX queue
> information. */
> > +	eth_fw_version_get_t       fw_version_get; /**< Get firmware
> version. */
> >   	eth_dev_supported_ptypes_get_t dev_supported_ptypes_get;
> >   	/**< Get packet types supported and identified by device. */
> >
> > @@ -2396,6 +2401,27 @@ void rte_eth_macaddr_get(uint8_t port_id,
> struct ether_addr *mac_addr);
> >   void rte_eth_dev_info_get(uint8_t port_id, struct rte_eth_dev_info
> > *dev_info);
> >
> >   /**
> > + * Retrieve the firmware version of a device.
> > + *
> > + * @param port_id
> > + *   The port identifier of the device.
> > + * @param fw_version
> > + *   A array pointer to store the firmware version of a device,
> > + *   allocated by caller.
> > + * @param fw_size
> > + *   The size of the array pointed by fw_version, which should be
> > + *   large enough to store firmware version of the device.
> > + * @return
> > + *   - (0) if successful.
> > + *   - (-ENOTSUP) if operation is not supported.
> > + *   - (-ENODEV) if *port_id* invalid.
> > + *   - (>0) if *fw_size* is not enough to store firmware version, return
> > + *          the size of the non truncated string.
> 
> It is OK for me to keep 0 for success here and it is right in this case to include
> terminating null iin the return value if size is insufficient (to cover corner case
> with empty FW version).
> Please, highlight that terminating null is included here. It is the difference
> from snprintf() and it should be 100% clear.
> 
You are right, I'll highlight that the firmware version stored here is include '\0'.

> > + */
> > +int rte_eth_dev_fw_version_get(uint8_t port_id,
> > +			       char *fw_version, size_t fw_size);
> > +
> > +/**
> >    * Retrieve the supported packet types of an Ethernet device.
> >    *
> >    * When a packet type is announced as supported, it *must* be
> > recognized by diff --git a/lib/librte_ether/rte_ether_version.map
> > b/lib/librte_ether/rte_ether_version.map
> > index 0c2859e..c6c9d0d 100644
> > --- a/lib/librte_ether/rte_ether_version.map
> > +++ b/lib/librte_ether/rte_ether_version.map
> > @@ -146,6 +146,7 @@ DPDK_17.02 {
> >   	global:
> >
> >   	_rte_eth_dev_reset;
> > +	rte_eth_dev_fw_version_get;
> >   	rte_flow_create;
> >   	rte_flow_destroy;
> >   	rte_flow_flush;
>