[dpdk-dev] [PATCH v6 1/4] 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 this function does 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          | 16 ++++++++++++
 lib/librte_ether/rte_ethdev.h          | 45 ++++++++++++++++++++++++++++++++++
 lib/librte_ether/rte_ether_version.map |  2 +-
 3 files changed, 62 insertions(+), 1 deletion(-)

diff --git a/lib/librte_ether/rte_ethdev.c b/lib/librte_ether/rte_ethdev.c
index 76179fd..21ea5bb 100644
--- a/lib/librte_ether/rte_ethdev.c
+++ b/lib/librte_ether/rte_ethdev.c
@@ -3414,3 +3414,19 @@ 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 fd6baf3..f5fd047 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. */
 
@@ -1430,6 +1433,7 @@ 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. */
@@ -2132,6 +2136,47 @@ 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.
+ *
+ * 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 08deb1f..d89a101 100644
--- a/lib/librte_ether/rte_ether_version.map
+++ b/lib/librte_ether/rte_ether_version.map
@@ -155,5 +155,5 @@ DPDK_17.08 {
 	rte_eth_dev_adjust_nb_rx_tx_desc;
 	rte_flow_copy;
 	rte_flow_isolate;
-
+	rte_eth_dev_reset;
 } DPDK_17.05;
-- 
2.7.5