[dpdk-dev] [PATCH v8 1/5] ethdev: add support of NIC reset

[Dai, Wei]

Many thanks, Remy.
My v9 patch set has followed your guidance.

> -----Original Message-----
> From: Horton, Remy
> Sent: Thursday, July 20, 2017 9:22 PM
> To: Dai, Wei <wei.dai at intel.com>; dev at dpdk.org
> Cc: thomas at monjalon.net; Lu, Wenzhuo <wenzhuo.lu at intel.com>;
> Ananyev, Konstantin <konstantin.ananyev at intel.com>; Xing, Beilei
> <beilei.xing at intel.com>; Wu, Jingjing <jingjing.wu at intel.com>; Mcnamara,
> John <john.mcnamara at intel.com>
> Subject: Re: [dpdk-dev] [PATCH v8 1/5] ethdev: add support of NIC reset
> 
> See suggested wording inline
> 
> On 17/07/2017 16:14, Wei Dai wrote:
> > This patch adds a new eth_dev layer API function rte_eth_dev_reset().
> > A DPDK application can call this function to reset a NIC and keep
> > its port id afterwards.
> > It means that all SW resources allocated in ethdev layer should be
> > kept and SW and HW resources of the NIC in PMD need to be reset in
> > similar way that it runs PCI dev_uninit() and then dev_init().
> > The sequence of dev_uninit() and dev_init() can be packed into a
> > single interface API rte_eth_dev_reset().
> > Please See the comments before the declaration of rte_eht_dev_reset()
> > in lib/librte_ether/rte_ethdev.h to get more details on why this
> > function is needed, what it does, when it should be called
> > and what an application should do after calling this function.
> 
> This patch adds a new eth_dev layer API function rte_eth_dev_reset(),
> which a DPDK application can call to reset a NIC and keep its port id
> afterwards. It means that all software resources allocated in the ethdev
> layer are kept, and software & hardware resources of the NIC within the
> NIC's PMD are reset to a state simular to that obtained by calling the
> PCI dev_uninit() and then dev_init(). This effective sequence of
> dev_uninit() and dev_init() is packed into a single API function
> rte_eth_dev_reset().
> 
> Please see the comments before the declaration of rte_eht_dev_reset()
> in lib/librte_ether/rte_ethdev.h to get more details on why this
> function is needed, what it does, when it should be called
> and what an application should do after calling this function.
> 
> 
> > Signed-off-by: Wei Dai <wei.dai at intel.com>
> > ---
> >  lib/librte_ether/rte_ethdev.c          | 17 +++++++++++++++++
> >  lib/librte_ether/rte_ethdev.h          | 33
> +++++++++++++++++++++++++++++++++
> >  lib/librte_ether/rte_ether_version.map |  1 +
> >  3 files changed, 51 insertions(+)
> 
> Reviewed-by: Remy Horton <remy.horton at intel.com>
> 
> 
> 
> >  /**
> > + * Reset a Ethernet device and keep its port id.
> > + *
> > + * When a port has to be reset passively, the DPDK application can invoke
> this
> > + * function. For example a PF is reset, all its VFs should also be reset.
> > + * Normally, a DPDK application can invoke this function when
> > + * RTE_ETH_EVENT_INTR_RESET event is detected. A DPDK application
> can also call
> > + * this function to start an initiative port reset.
> 
> When a port has to be reset passively, the DPDK application can invoke
> this function. For example when a PF is reset, all its VFs should also
> be reset. Normally a DPDK application can invoke this function when
> RTE_ETH_EVENT_INTR_RESET event is detected, but can also use it to start
> a port reset in other circumstances.
> 
> > + * When this function is called, it first stops the port and then call PMD
> > + * specific dev_uninit( ) and  dev_init( ) to makes the port return to initial
> > + * status in which no any Tx queue and no Rx queue are setup and the port
> has
> > + * just be reset and not started. And the port keeps its port id after calling
> > + * this function.
> 
> When this function is called, it first stops the port and then calls the
> PMD specific dev_uninit( ) and dev_init( ) to return the port to initial
> state, in which no Tx and Rx queues are setup, as if the port has been
> reset and not started. The port keeps the port id it had before the
> function call.
> 
> > + * After calling rte_eth_dev_reset( ), the application should go through
> > + * rte_eth_dev_configure( ), rte_eth_rx_queue_setup( ),
> > + * rte_eth_tx_queue_setup( ) and rte_eth_dev_start( ) again to restore
> > + * its previous settings or to reconfigure itself with different settings.
> 
> After calling rte_eth_dev_reset( ), the application should use
> rte_eth_dev_configure( ), rte_eth_rx_queue_setup( ),
> rte_eth_tx_queue_setup( ), and rte_eth_dev_start( )
> to reconfigure the device as appropriate.
> 
> 
> > + * Note: to avoid unexpected behaviour, the application should stop
> calling Rx
> > + *       and Rx function before calling rte_eth_dev_reset( ).For thread
> safety,
> > + *       all these controlling operations had better be made in same
> thread.
> 
> Note: To avoid unexpected behavior, the application should stop calling
> Tx and Rx functions before calling rte_eth_dev_reset( ). For thread
> safety, all these controlling functions should be called from the same
> thread.
>