[PATCH v3 2/4] ethdev: add siblings iterators

[Thomas Monjalon <thomas@monjalon.net>]

If multiple ports share the same hardware device (rte_device),
they are siblings and can be found thanks to the new functions
and loop macros.
One iterator takes a port id as reference,
while the other one directly refers to the parent device.

The ownership is not checked because siblings may have
different owners.

Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
---
v2: Reviewed-by: Andrew Rybchenko - not kept because of changes in v3

v3:
	- fix logic + re-use rte_eth_find_next()
	- longer parameter names
	- more and better doxygen comments
---
 lib/librte_ethdev/rte_ethdev.c           | 19 +++++++
 lib/librte_ethdev/rte_ethdev.h           | 63 ++++++++++++++++++++++++
 lib/librte_ethdev/rte_ethdev_version.map |  2 +
 3 files changed, 84 insertions(+)

diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
index 33cffc498..3b125a642 100644
--- a/lib/librte_ethdev/rte_ethdev.c
+++ b/lib/librte_ethdev/rte_ethdev.c
@@ -339,6 +339,25 @@ rte_eth_find_next(uint16_t port_id)
 	return port_id;
 }
 
+uint16_t __rte_experimental
+rte_eth_find_next_of(uint16_t port_id, const struct rte_device *parent)
+{
+	port_id = rte_eth_find_next(port_id);
+	while (port_id < RTE_MAX_ETHPORTS &&
+			rte_eth_devices[port_id].device != parent)
+		port_id = rte_eth_find_next(port_id + 1);
+
+	return port_id;
+}
+
+uint16_t __rte_experimental
+rte_eth_find_next_sibling(uint16_t port_id, uint16_t ref_port_id)
+{
+	RTE_ETH_VALID_PORTID_OR_ERR_RET(ref_port_id, RTE_MAX_ETHPORTS);
+	return rte_eth_find_next_of(port_id,
+			rte_eth_devices[ref_port_id].device);
+}
+
 static void
 rte_eth_dev_shared_data_prepare(void)
 {
diff --git a/lib/librte_ethdev/rte_ethdev.h b/lib/librte_ethdev/rte_ethdev.h
index b6023c050..3d5bacaee 100644
--- a/lib/librte_ethdev/rte_ethdev.h
+++ b/lib/librte_ethdev/rte_ethdev.h
@@ -1387,6 +1387,69 @@ uint16_t rte_eth_find_next(uint16_t port_id);
 #define RTE_ETH_FOREACH_DEV(p) \
 	RTE_ETH_FOREACH_DEV_OWNED_BY(p, RTE_ETH_DEV_NO_OWNER)
 
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Iterates over ethdev ports of a specified device.
+ *
+ * @param port_id_start
+ *   The id of the next possible valid port.
+ * @param parent
+ *   The generic device behind the ports to iterate.
+ * @return
+ *   Next port id of the device, possibly port_id_start,
+ *   RTE_MAX_ETHPORTS if there is none.
+ */
+__rte_experimental
+uint16_t rte_eth_find_next_of(uint16_t port_id_start,
+		const struct rte_device *parent);
+
+/**
+ * Macro to iterate over all ethdev ports of a specified device.
+ *
+ * @param port_id
+ *   The id of the matching port being iterated.
+ * @param parent
+ *   The rte_device pointer matching the iterated ports.
+ */
+#define RTE_ETH_FOREACH_DEV_OF(port_id, parent) \
+	for (port_id = rte_eth_find_next_of(0, parent); \
+		port_id < RTE_MAX_ETHPORTS; \
+		port_id = rte_eth_find_next_of(port_id + 1, parent))
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Iterates over sibling ethdev ports (i.e. sharing the same rte_device).
+ *
+ * @param port_id_start
+ *   The id of the next possible valid sibling port.
+ * @param ref_port_id
+ *   The id of a reference port to compare rte_device with.
+ * @return
+ *   Next sibling port id, possibly port_id_start or ref_port_id itself,
+ *   RTE_MAX_ETHPORTS if there is none.
+ */
+__rte_experimental
+uint16_t rte_eth_find_next_sibling(uint16_t port_id_start,
+		uint16_t ref_port_id);
+
+/**
+ * Macro to iterate over all ethdev ports sharing the same rte_device
+ * as the specified port.
+ * Note: the specified reference port is part of the loop iterations.
+ *
+ * @param port_id
+ *   The id of the matching port being iterated.
+ * @param ref_port_id
+ *   The id of the port being compared.
+ */
+#define RTE_ETH_FOREACH_DEV_SIBLING(port_id, ref_port_id) \
+	for (port_id = rte_eth_find_next_sibling(0, ref_port_id); \
+		port_id < RTE_MAX_ETHPORTS; \
+		port_id = rte_eth_find_next_sibling(port_id + 1, ref_port_id))
 
 /**
  * @warning
diff --git a/lib/librte_ethdev/rte_ethdev_version.map b/lib/librte_ethdev/rte_ethdev_version.map
index 92ac3de25..b37a4167d 100644
--- a/lib/librte_ethdev/rte_ethdev_version.map
+++ b/lib/librte_ethdev/rte_ethdev_version.map
@@ -245,6 +245,8 @@ EXPERIMENTAL {
 	rte_eth_dev_owner_set;
 	rte_eth_dev_owner_unset;
 	rte_eth_dev_rx_intr_ctl_q_get_fd;
+	rte_eth_find_next_of;
+	rte_eth_find_next_sibling;
 	rte_eth_switch_domain_alloc;
 	rte_eth_switch_domain_free;
 	rte_flow_conv;
-- 
2.21.0