Re: [PATCH v6 1/4] lib/librte_ether: support device reset

[Jerin Jacob <jerin.jacob@caviumnetworks.com>]

On Mon, Jun 20, 2016 at 02:24:27PM +0800, Wenzhuo Lu wrote:
> Add an API to reset the device.
> It's for VF device in this scenario, kernel PF + DPDK VF.
> When the PF port down->up, APP should call this API to
> reset VF port. Most likely, APP should call it in its
> management thread and guarantee the thread safe. It means
> APP should stop the rx/tx and the device, then reset the
> device, then recover the device and rx/tx.

Following is _a_ use-case for Device reset. But may be not be _the_ use
case. IMO, We need to first say expected behavior of this API and add a use-case
later.

Other use-case would be, PCIe VF with functional level reset for SRIOV
migration.
Are we on same page?

> 
> Signed-off-by: Wenzhuo Lu <wenzhuo.lu@intel.com>
> ---
>  doc/guides/nics/overview.rst           |  1 +
>  lib/librte_ether/rte_ethdev.c          | 17 +++++++++++++++++
>  lib/librte_ether/rte_ethdev.h          | 24 ++++++++++++++++++++++++
>  lib/librte_ether/rte_ether_version.map |  7 +++++++
>  4 files changed, 49 insertions(+)
> 
> diff --git a/doc/guides/nics/overview.rst b/doc/guides/nics/overview.rst
> index 0bd8fae..c8a4985 100644
> --- a/doc/guides/nics/overview.rst
> +++ b/doc/guides/nics/overview.rst
> @@ -89,6 +89,7 @@ Most of these differences are summarized below.
>     Speed capabilities
>     Link status            Y Y   Y Y   Y Y Y     Y   Y Y Y Y         Y Y         Y Y   Y Y Y Y
>     Link status event      Y Y     Y     Y Y     Y   Y Y             Y Y         Y Y     Y
> +   Link reset                               Y Y   Y     Y Y

More appropriate would be "Device reset" ? Right?

>     Queue status event                                                                   Y
>     Rx interrupt                   Y     Y Y Y Y Y Y Y Y Y Y Y Y Y Y
>     Queue start/stop             Y   Y Y Y Y Y Y     Y Y     Y Y Y Y Y Y               Y   Y Y
> diff --git a/lib/librte_ether/rte_ethdev.c b/lib/librte_ether/rte_ethdev.c
> index e148028..6c0449b 100644
> --- a/lib/librte_ether/rte_ethdev.c
> +++ b/lib/librte_ether/rte_ethdev.c
> @@ -3346,3 +3346,20 @@ rte_eth_dev_l2_tunnel_offload_set(uint8_t port_id,
>  				-ENOTSUP);
>  	return (*dev->dev_ops->l2_tunnel_offload_set)(dev, l2_tunnel, mask, en);
>  }
> +
> +int
> +rte_eth_dev_reset(uint8_t port_id)
> +{
> +	struct rte_eth_dev *dev;
> +	int diag;
> +
> +	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->dev_reset, -ENOTSUP);
> +
> +	diag = (*dev->dev_ops->dev_reset)(dev);
> +
> +	return diag;
> +}
> diff --git a/lib/librte_ether/rte_ethdev.h b/lib/librte_ether/rte_ethdev.h
> index 2757510..5b3ba12 100644
> --- a/lib/librte_ether/rte_ethdev.h
> +++ b/lib/librte_ether/rte_ethdev.h
> @@ -1318,6 +1318,9 @@ typedef int (*eth_l2_tunnel_offload_set_t)
>  	 uint8_t en);
>  /**< @internal enable/disable the l2 tunnel offload functions */
>  
> +typedef int  (*eth_dev_reset_t)(struct rte_eth_dev *dev);
> +/**< @internal Function used to reset a configured Ethernet device. */
> +
>  #ifdef RTE_NIC_BYPASS
>  
>  enum {
> @@ -1508,6 +1511,8 @@ struct eth_dev_ops {
>  	eth_l2_tunnel_eth_type_conf_t l2_tunnel_eth_type_conf;
>  	/** Enable/disable l2 tunnel offload functions */
>  	eth_l2_tunnel_offload_set_t l2_tunnel_offload_set;
> +	/** Reset device. */
> +	eth_dev_reset_t dev_reset;
>  };
>  
>  /**
> @@ -4253,6 +4258,25 @@ rte_eth_dev_l2_tunnel_offload_set(uint8_t port_id,
>  				  uint32_t mask,
>  				  uint8_t en);
>  
> +/**
> + * Reset an ethernet device when it's not working. One scenario is, after PF
> + * port is down and up, the related VF port should be reset.
> + * The API will stop the port, clear the rx/tx queues, re-setup the rx/tx
> + * queues, restart the port.
> + * Before calling this API, APP should stop the rx/tx. When tx is being stopped,
> + * APP can drop the packets and release the buffer instead of sending them.

Same as first comment.

> + *
> + * @param port_id
> + *   The port identifier of the Ethernet device.
> + *
> + * @return
> + *   - (0) if successful.
> + *   - (-ENODEV) if port identifier is invalid.
> + *   - (-ENOTSUP) if hardware doesn't support this function.
> + */
> +int
> +rte_eth_dev_reset(uint8_t port_id);
> +
>  #ifdef __cplusplus
>  }
>  #endif
> diff --git a/lib/librte_ether/rte_ether_version.map b/lib/librte_ether/rte_ether_version.map
> index 214ecc7..c34207e 100644
> --- a/lib/librte_ether/rte_ether_version.map
> +++ b/lib/librte_ether/rte_ether_version.map
> @@ -132,3 +132,10 @@ DPDK_16.04 {
>  	rte_eth_tx_buffer_set_err_callback;
>  
>  } DPDK_2.2;
> +
> +DPDK_16.07 {
> +	global:
> +
> +	rte_eth_dev_reset;
> +
> +} DPDK_16.04;
> -- 
> 1.9.3
>