[dpdk-dev] [PATCH v7 1/5] ethdev: add support of NIC reset

[Wei Dai]

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.

Signed-off-by: Wei Dai <wei.dai at intel.com>
---
 lib/librte_ether/rte_ethdev.c          | 17 ++++++++
 lib/librte_ether/rte_ethdev.h          | 73 ++++++++++++++++++++++++++++++++++
 lib/librte_ether/rte_ether_version.map |  1 +
 3 files changed, 91 insertions(+)

diff --git a/lib/librte_ether/rte_ethdev.c b/lib/librte_ether/rte_ethdev.c
index a1b7447..4172d82 100644
--- a/lib/librte_ether/rte_ethdev.c
+++ b/lib/librte_ether/rte_ethdev.c
@@ -3415,3 +3415,20 @@ rte_eth_dev_adjust_nb_rx_tx_desc(uint8_t port_id,
 
 	return 0;
 }
+
+int
+rte_eth_dev_reset(uint8_t port_id)
+{
+	struct rte_eth_dev *dev;
+	int ret;
+
+	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -EINVAL);
+	dev = &rte_eth_devices[port_id];
+
+	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->dev_reset, -ENOTSUP);
+
+	rte_eth_dev_stop(port_id);
+	ret = dev->dev_ops->dev_reset(dev);
+
+	return ret;
+}
diff --git a/lib/librte_ether/rte_ethdev.h b/lib/librte_ether/rte_ethdev.h
index f683727..c458c52 100644
--- a/lib/librte_ether/rte_ethdev.h
+++ b/lib/librte_ether/rte_ethdev.h
@@ -1113,6 +1113,9 @@ typedef int  (*eth_dev_set_link_down_t)(struct rte_eth_dev *dev);
 typedef void (*eth_dev_close_t)(struct rte_eth_dev *dev);
 /**< @internal Function used to close a configured Ethernet device. */
 
+typedef int (*eth_dev_reset_t)(struct rte_eth_dev *dev);
+/** <@internal Function used to reset a configured Ethernet device. */
+
 typedef void (*eth_promiscuous_enable_t)(struct rte_eth_dev *dev);
 /**< @internal Function used to enable the RX promiscuous mode of an Ethernet device. */
 
@@ -1433,6 +1436,7 @@ struct eth_dev_ops {
 	eth_dev_set_link_up_t      dev_set_link_up;   /**< Device link up. */
 	eth_dev_set_link_down_t    dev_set_link_down; /**< Device link down. */
 	eth_dev_close_t            dev_close;     /**< Close device. */
+	eth_dev_reset_t		   dev_reset;	  /**< Reset device. */
 	eth_link_update_t          link_update;   /**< Get device link state. */
 
 	eth_promiscuous_enable_t   promiscuous_enable; /**< Promiscuous ON. */
@@ -2138,6 +2142,75 @@ int rte_eth_dev_set_link_down(uint8_t port_id);
 void rte_eth_dev_close(uint8_t port_id);
 
 /**
+ * Reset a Ethernet device and keep its port id.
+ *
+ * A DPDK application calls this function to do an initiative or passive
+ * reset of a port.
+ *
+ * Sometimes a port have to be reset passively. For example a PF is reset,
+ * all its VFs should also be reset by application itself to align with the
+ * PF. A DPDK application also can call this function to trigger an initative
+ * port reset.
+ *
+ * When processing reset, if the port goes through PCI remove() and then
+ * PCI probe() for restoration, its port id may be changed and this is not
+ * expected by some DPDK application.
+ *
+ * Normally, PCI probe() includes two parts: one is in rte_ethdev layer
+ * to allocate resource in rte_ethdev layer and the other is calling PMD
+ * specific dev_init() to allocate and initialize resource in PMD layer.
+ * PCI remove( ) releases all resource allocated from rte_ethdev layer
+ * in PCI probe( ) and calls PMD specific dev_uninit( ) to releaase
+ * resource allocated by dev_init( ) in PMD layer.
+ *
+ * To keep same port id and reset the port, only dev_uninit() and
+ * dev_init( ) in PMD can be called and keep all resources allocated
+ * from rte_ethdev layer poart in PCI probe( ). All these are what
+ * rte_eth_dev_reset() does.
+ *
+ * The rte_eth_dev_reset( ) calls rte_eth_dev_stop( ), PMD dev_uninit( )
+ * and then PMD dev_init( ) to reset a port and keep same port id.
+ *
+ * Normally, a DPDK application can invoke this function when
+ * RTE_ETH_EVENT_INTR_RESET event is detected.
+
+ * It is duty of PMD to trigger RTE_ETH_EVENT_INTR_RESET event and application
+ * should also register some callback function to handle this event.
+ * When PMD needs to trigger a reset, it can trigger RTE_ETH_EVENT_INTR_RESET.
+ * On the received event of RTE_ETH_EVENT_INTR_RESET, application can begin to
+ * handle it:  stop working queues,  make rx and tx function not be called and
+ * then call rte_eth_dev_reset( ).For thread safety, all these controlling
+ * operations had better be made in same thread.
+ *
+ * For example, when PF is reset, PF send a message to notify VF this event and
+ * also trigger an interrupt to VF.  And then in the interrupt service routine
+ * DPDK VF detect this notification message and calls
+ * _rte_eth_dev_callback_process(dev, RTE_ETH_EVENT_INTR_RESET, NULL, NULL).
+ * So it means that PF reset trigger RTE_ETH_EVENT_INTR_RESET event in VF.
+ * The function _rte_eth_dev_callback_process( ) will call the registered
+ * callback function. The callback function can trigger application to handle
+ * all operations of VF reset including something like stopping working Rx/Tx
+ * queues and call this rte_eth_dev_reset().
+ *
+ * The rte_eth_dev_reset( ) itself is generic function which only does some HW
+ * reset operations through calling dev_unint() and dev_init(). And itself
+ * doesn't handle above synchronization which is handled by application.
+ *
+ * PMD itself should not call rte_eth_dev_reset( ). PMD can trigger application
+ * to handle reset event. It is duty of application to handle all
+ * synchronizations befort it calls rte_eth_dev_reset( ).
+ *
+ * After calling rte_eth_dev_reset( ), the application can 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.
+ *
+ * @param port_id
+ *   The port identifier of the Ethernet device.
+ */
+int rte_eth_dev_reset(uint8_t port_id);
+
+/**
  * Enable receipt in promiscuous mode for an Ethernet device.
  *
  * @param port_id
diff --git a/lib/librte_ether/rte_ether_version.map b/lib/librte_ether/rte_ether_version.map
index 4283728..e86d51e 100644
--- a/lib/librte_ether/rte_ether_version.map
+++ b/lib/librte_ether/rte_ether_version.map
@@ -155,6 +155,7 @@ DPDK_17.08 {
 	rte_eth_dev_adjust_nb_rx_tx_desc;
 	rte_flow_copy;
 	rte_flow_isolate;
+	rte_eth_dev_reset;
 	rte_tm_capabilities_get;
 	rte_tm_get_leaf_nodes;
 	rte_tm_hierarchy_commit;
-- 
2.7.5