[PATCH v6 2/2] ethdev: get the supported pool for a port

[Santosh Shukla <santosh.shukla@caviumnetworks.com>]

Now that dpdk supports more than one mempool drivers and
each mempool driver works best for specific PMD, example:
- sw ring based mempool for Intel PMD drivers.
- dpaa2 HW mempool manager for dpaa2 PMD driver.
- fpa HW mempool manager for Octeontx PMD driver.

Application would like to know the best mempool handle
for any port.

Introducing rte_eth_dev_pool_ops_supported() API,
which allows PMD driver to advertise
his supported pool capability to the application.

Supported pools are categorized in below priority:-
- Best mempool handle for this port (Highest priority '0')
- Port supports this mempool handle (Priority '1')

Signed-off-by: Santosh Shukla <santosh.shukla@caviumnetworks.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>
---
v5 --> v6:
- Arranged alphabetical order for rte_eth_dev_pool_ops_supported.
  (Suggested by Thomas)

v4 --> v5:
- Incorporated wording comment perv 4 feedback, refer [1](Suggested by Olivier)
- Note: Implementation assume that if PMD does not implement
  _pool_ops_supported() then library will return '1'.. assuming that
  PMD supports all the pool ops. (Proposed by Olivier)

[1] http://dpdk.org/dev/patchwork/patch/28596/

v3 --> v4:
- Replaced __preferred_pool() with
rte_eth_dev_pools_ops_supported() (suggested by Olivier)

History, Refer [2].
[2] http://dpdk.org/dev/patchwork/patch/27610/

 lib/librte_ether/rte_ethdev.c           | 18 ++++++++++++++++++
 lib/librte_ether/rte_ethdev.h           | 24 ++++++++++++++++++++++++
 lib/librte_ether/rte_ethdev_version.map |  1 +
 3 files changed, 43 insertions(+)

diff --git a/lib/librte_ether/rte_ethdev.c b/lib/librte_ether/rte_ethdev.c
index 1849a3bdd..f0b647e10 100644
--- a/lib/librte_ether/rte_ethdev.c
+++ b/lib/librte_ether/rte_ethdev.c
@@ -3437,3 +3437,21 @@ rte_eth_dev_adjust_nb_rx_tx_desc(uint8_t port_id,
 
 	return 0;
 }
+
+int
+rte_eth_dev_pool_ops_supported(uint8_t port_id, const char *pool)
+{
+	struct rte_eth_dev *dev;
+
+	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
+
+	if (pool == NULL)
+		return -EINVAL;
+
+	dev = &rte_eth_devices[port_id];
+
+	if (*dev->dev_ops->pool_ops_supported == NULL)
+		return 1; /* all pools are supported */
+
+	return (*dev->dev_ops->pool_ops_supported)(dev, pool);
+}
diff --git a/lib/librte_ether/rte_ethdev.h b/lib/librte_ether/rte_ethdev.h
index 99cdd54d4..c65b64d40 100644
--- a/lib/librte_ether/rte_ethdev.h
+++ b/lib/librte_ether/rte_ethdev.h
@@ -1428,6 +1428,10 @@ typedef int (*eth_get_dcb_info)(struct rte_eth_dev *dev,
 				 struct rte_eth_dcb_info *dcb_info);
 /**< @internal Get dcb information on an Ethernet device */
 
+typedef int (*eth_pool_ops_supported_t)(struct rte_eth_dev *dev,
+						const char *pool);
+/**< @internal Test if a port supports specific mempool ops */
+
 /**
  * @internal A structure containing the functions exported by an Ethernet driver.
  */
@@ -1548,6 +1552,8 @@ struct eth_dev_ops {
 
 	eth_tm_ops_get_t tm_ops_get;
 	/**< Get Traffic Management (TM) operations. */
+	eth_pool_ops_supported_t pool_ops_supported;
+	/**< Test if a port supports specific mempool ops */
 };
 
 /**
@@ -4470,6 +4476,24 @@ int rte_eth_dev_adjust_nb_rx_tx_desc(uint8_t port_id,
 				     uint16_t *nb_rx_desc,
 				     uint16_t *nb_tx_desc);
 
+
+/**
+ * Test if a port supports specific mempool ops.
+ *
+ * @param port_id
+ *   Port identifier of the Ethernet device.
+ * @param [in] pool
+ *   The name of the pool operations to test.
+ * @return
+ *   - 0: best mempool ops choice for this port.
+ *   - 1: mempool ops are supported for this port.
+ *   - -ENOTSUP: mempool ops not supported for this port.
+ *   - -ENODEV: Invalid port Identifier.
+ *   - -EINVAL: Pool param is null.
+ */
+int
+rte_eth_dev_pool_ops_supported(uint8_t port_id, const char *pool);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/librte_ether/rte_ethdev_version.map b/lib/librte_ether/rte_ethdev_version.map
index 07f9e17f6..92c9e2908 100644
--- a/lib/librte_ether/rte_ethdev_version.map
+++ b/lib/librte_ether/rte_ethdev_version.map
@@ -191,6 +191,7 @@ DPDK_17.08 {
 DPDK_17.11 {
 	global:
 
+	rte_eth_dev_pool_ops_supported;
 	rte_eth_dev_reset;
 
 } DPDK_17.08;
-- 
2.14.1