[dpdk-dev] [RFC PATCH] ethdev: support congestion management

[<jerinj@marvell.com>]

From: Jerin Jacob <jerinj@marvell.com>

NIC HW controllers often come with congestion management support on
various HW objects such as Rx queue depth or mempool queue depth.

Also, it can support various modes of operation such as RED
(Random early discard), WRED etc on those HW objects.

This patch adds a framework to express such modes(enum rte_cman_mode)
and introduce (enum rte_eth_cman_obj) to enumerate the different
objects where the modes can operate on.

This patch adds RTE_CMAN_RED mode of operation and
RTE_ETH_CMAN_OBJ_RX_QUEUE, RTE_ETH_CMAN_OBJ_RX_QUEUE_MEMPOOL object.

Introduced reserved fields in configuration structure
backed by rte_eth_cman_config_init() to add new configuration
parameters without ABI breakage.

Added rte_eth_cman_info_get() API to get the information such as
supported modes and objects.

Added rte_eth_cman_config_init(), rte_eth_cman_config_set() APIs
to configure congestion management on those object with associated mode.

Finally, Added rte_eth_cman_config_get() API to retrieve the
applied configuration.

Signed-off-by: Jerin Jacob <jerinj@marvell.com>
---
 doc/guides/nics/features.rst         |  12 +++
 doc/guides/nics/features/default.ini |   1 +
 lib/eal/include/meson.build          |   1 +
 lib/eal/include/rte_cman.h           |  51 ++++++++++
 lib/ethdev/rte_ethdev.h              | 145 +++++++++++++++++++++++++++
 5 files changed, 210 insertions(+)
 create mode 100644 lib/eal/include/rte_cman.h

diff --git a/doc/guides/nics/features.rst b/doc/guides/nics/features.rst
index 21bedb743f..ffcc2bcc92 100644
--- a/doc/guides/nics/features.rst
+++ b/doc/guides/nics/features.rst
@@ -727,6 +727,18 @@ Supports configuring per-queue stat counter mapping.
   ``rte_eth_dev_set_tx_queue_stats_mapping()``.
 
 
+.. _nic_features_congestion_management
+
+Congestion management
+---------------------
+
+Supports congestion management.
+
+* **[implements] eth_dev_ops**: ``cman_info_get``, ``cman_config_set``, ``cman_config_get``.
+* **[related]    API**: ``rte_eth_cman_info_get()``, ``rte_eth_cman_config_init()``,
+  ``rte_eth_cman_config_set()``, ``rte_eth_cman_config_get()``.
+
+
 .. _nic_features_fw_version:
 
 FW version
diff --git a/doc/guides/nics/features/default.ini b/doc/guides/nics/features/default.ini
index b1d18ac62c..060497e41f 100644
--- a/doc/guides/nics/features/default.ini
+++ b/doc/guides/nics/features/default.ini
@@ -60,6 +60,7 @@ Tx descriptor status =
 Basic stats          =
 Extended stats       =
 Stats per queue      =
+Congestion management =
 FW version           =
 EEPROM dump          =
 Module EEPROM dump   =
diff --git a/lib/eal/include/meson.build b/lib/eal/include/meson.build
index 9700494816..40e31e0e6d 100644
--- a/lib/eal/include/meson.build
+++ b/lib/eal/include/meson.build
@@ -10,6 +10,7 @@ headers += files(
         'rte_branch_prediction.h',
         'rte_bus.h',
         'rte_class.h',
+        'rte_cman.h',
         'rte_common.h',
         'rte_compat.h',
         'rte_debug.h',
diff --git a/lib/eal/include/rte_cman.h b/lib/eal/include/rte_cman.h
new file mode 100644
index 0000000000..e6dad2ebf7
--- /dev/null
+++ b/lib/eal/include/rte_cman.h
@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(C) 2022 Marvell International Ltd.
+ */
+
+#ifndef RTE_CMAN_H
+#define RTE_CMAN_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <rte_bitops.h>
+
+/**
+ * @file
+ * Congestion management related parameters for DPDK.
+ */
+
+/** Congestion management modes */
+enum rte_cman_mode {
+	/** Congestion based on Random Early Detection.
+	 *
+	 * https://en.wikipedia.org/wiki/Random_early_detection
+	 * @see struct rte_cman_red_params
+	 */
+	RTE_CMAN_RED = RTE_BIT64(0),
+};
+
+/**
+ * RED based congestion management configuration parameters.
+ */
+struct rte_cman_red_params {
+	/**< Minimum threshold (min_th) value
+	 *
+	 * Value expressed as percentage. Value must be in 0 to 100(inclusive).
+	 */
+	uint8_t min_th;
+	/**< Maximum threshold (max_th) value
+	 *
+	 * Value expressed as percentage. Value must be in 0 to 100(inclusive).
+	 */
+	uint8_t max_th;
+	/** Inverse of packet marking probability maximum value (maxp = 1 / maxp_inv) */
+	uint16_t maxp_inv;
+};
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* RTE_CMAN_H */
diff --git a/lib/ethdev/rte_ethdev.h b/lib/ethdev/rte_ethdev.h
index 04cff8ee10..7c8718bb2e 100644
--- a/lib/ethdev/rte_ethdev.h
+++ b/lib/ethdev/rte_ethdev.h
@@ -160,6 +160,7 @@ extern "C" {
 #define RTE_ETHDEV_DEBUG_TX
 #endif
 
+#include <rte_cman.h>
 #include <rte_compat.h>
 #include <rte_log.h>
 #include <rte_interrupts.h>
@@ -5452,6 +5453,150 @@ typedef struct {
 __rte_experimental
 int rte_eth_dev_priv_dump(uint16_t port_id, FILE *file);
 
+/* Congestion management */
+
+/** Enumerate list of ethdev congestion management objects */
+enum rte_eth_cman_obj {
+	/** Congestion management based on Rx queue depth */
+	RTE_ETH_CMAN_OBJ_RX_QUEUE = RTE_BIT64(0),
+	/** Congestion management based on mempool depth associated with Rx queue
+	 * @see rte_eth_rx_queue_setup()
+	 */
+	RTE_ETH_CMAN_OBJ_RX_QUEUE_MEMPOOL = RTE_BIT64(1),
+};
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change, or be removed, without prior notice
+ *
+ * A structure used to retrieve information of ethdev congestion management.
+ */
+struct rte_eth_cman_info {
+	/** Set of supported congestion management modes
+	 * @see enum rte_cman_mode
+	 */
+	uint64_t modes_supported;
+	/** Set of supported congestion management objects
+	 * @see enum rte_eth_cman_obj
+	 */
+	uint64_t objs_supported;
+	/** Reserved for future fields */
+	uint8_t rsvd[64];
+};
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change, or be removed, without prior notice
+ *
+ * A structure used to configure the ethdev congestion management.
+ */
+struct rte_eth_cman_config {
+	/** Congestion management object */
+	enum rte_eth_cman_obj obj;
+	/** Congestion management mode */
+	enum rte_cman_mode mode;
+	union {
+		/** Rx queue to configure congestion management.
+		 *
+		 * Valid when object is RTE_ETH_CMAN_OBJ_RX_QUEUE or
+		 * RTE_ETH_CMAN_OBJ_RX_QUEUE_MEMPOOL.
+		 */
+		uint16_t rx_queue;
+		/** Reserved for future fields */
+		uint8_t rsvd_obj_params[16];
+	} obj_param;
+	union {
+		/** RED configuration parameters.
+		 *
+		 * Valid when mode is RTE_CMAN_RED.
+		 */
+		struct rte_cman_red_params red;
+		/** Reserved for future fields */
+		uint8_t rsvd_mode_params[64];
+	} mode_param;
+};
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change, or be removed, without prior notice
+ *
+ * Retrieve the information for ethdev congestion management
+ *
+ * @param port_id
+ *   The port identifier of the Ethernet device.
+ * @param info
+ *   A pointer to a structure of type *rte_eth_cman_info* to be filled with
+ *   the information about congestion management.
+ * @return
+ *   - (0) if successful.
+ *   - (-ENOTSUP) if support for cman_info_get does not exist.
+ *   - (-ENODEV) if *port_id* invalid.
+ *   - (-EINVAL) if bad parameter.
+ */
+__rte_experimental
+int rte_eth_cman_info_get(uint16_t port_id, struct rte_eth_cman_info *info);
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change, or be removed, without prior notice
+ *
+ * Initialize the ethdev congestion management configuration structure with default values.
+ *
+ * @param port_id
+ *   The port identifier of the Ethernet device.
+ * @param config
+ *   A pointer to a structure of type *rte_eth_cman_config* to be initialized
+ *   with default value.
+ * @return
+ *   - (0) if successful.
+ *   - (-ENODEV) if *port_id* invalid.
+ *   - (-EINVAL) if bad parameter.
+ */
+__rte_experimental
+int rte_eth_cman_config_init(uint16_t port_id, struct rte_eth_cman_config *config);
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change, or be removed, without prior notice
+ *
+ * Configure ethdev congestion management
+ *
+ * @param port_id
+ *   The port identifier of the Ethernet device.
+ * @param config
+ *   A pointer to a structure of type *rte_eth_cman_config* to be configured.
+ * @return
+ *   - (0) if successful.
+ *   - (-ENOTSUP) if support for cman_config_set does not exist.
+ *   - (-ENODEV) if *port_id* invalid.
+ *   - (-EINVAL) if bad parameter.
+ */
+__rte_experimental
+int rte_eth_cman_config_set(uint16_t port_id, struct rte_eth_cman_config *config);
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change, or be removed, without prior notice
+ *
+ * Retrieve the applied ethdev congestion management parameters for the given port.
+ *
+ * @param port_id
+ *   The port identifier of the Ethernet device.
+ * @param config
+ *   A pointer to a structure of type *rte_eth_cman_config* to retrieve
+ *   congestion management parameters for the given object.
+ *   Application must fill all parameters except mode_param parameter in
+ *   struct rte_eth_cman_config.
+ *
+ * @return
+ *   - (0) if successful.
+ *   - (-ENOTSUP) if support for cman_config_get does not exist.
+ *   - (-ENODEV) if *port_id* invalid.
+ *   - (-EINVAL) if bad parameter.
+ */
+__rte_experimental
+int rte_eth_cman_config_get(uint16_t port_id, struct rte_eth_cman_config *config);
+
 #include <rte_ethdev_core.h>
 
 /**
-- 
2.36.1