[PATCH] doc: update documentation for ICE DCB and PFC features

[Vladimir Medvedkin]

Add DCB and PFC documentation. Update feature matrix
and release notes.

Signed-off-by: Vladimir Medvedkin <vladimir.medvedkin at intel.com>
---
 doc/guides/nics/features/ice.ini       |  1 +
 doc/guides/nics/ice.rst                | 74 ++++++++++++++++++++++++++
 doc/guides/rel_notes/release_25_11.rst |  4 ++
 3 files changed, 79 insertions(+)

diff --git a/doc/guides/nics/features/ice.ini b/doc/guides/nics/features/ice.ini
index 2703493514..e9796c1eab 100644
--- a/doc/guides/nics/features/ice.ini
+++ b/doc/guides/nics/features/ice.ini
@@ -24,6 +24,7 @@ Scattered Rx         = Y
 TSO                  = Y
 Promiscuous mode     = Y
 Allmulticast mode    = Y
+DCB                  = Y
 Unicast MAC filter   = Y
 RSS hash             = Y
 RSS key update       = Y
diff --git a/doc/guides/nics/ice.rst b/doc/guides/nics/ice.rst
index 7e9ba23102..7fe61daaf3 100644
--- a/doc/guides/nics/ice.rst
+++ b/doc/guides/nics/ice.rst
@@ -447,6 +447,80 @@ and add the ``--force-max-simd-bitwidth=64`` startup parameter to disable vector
 
    examples/dpdk-ptpclient -l 0-3 -n 3 -a 0000:ec:00.1 --force-max-simd-bitwidth=64 -- -T 1 -p 0x1 -c 1
 
+Data Center Bridging (DCB) and Priority Flow Control (PFC)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The ice PMD supports Data Center Bridging (DCB) and Priority Flow Control (PFC).
+These features enable Quality of Service (QoS) in data center environments by allowing
+traffic classification and prioritization across multiple traffic classes.
+
+DCB Configuration
+^^^^^^^^^^^^^^^^^
+
+DCB can be enabled by configuring the device with ``RTE_ETH_MQ_RX_DCB_FLAG`` in the Rx mode
+during device configuration.
+
+The ice PMD supports:
+
+* 4 or 8 traffic classes (TCs)
+* VLAN Priority to Traffic Class mapping
+* All TCs configured with Enhanced Transmission Selection (ETS) with even bandwidth allocation
+* Queues are evenly distributed across configured TCs
+
+Requirements:
+
+* The number of queues must be evenly divisible by the number of traffic classes
+* The number of queues per TC must be a power of 2
+* Traffic classes must be configured contiguously starting from TC 0
+
+Example DCB configuration in testpmd:
+
+.. code-block:: console
+
+   dpdk-testpmd -a 0000:18:00.0 -- -i --nb-cores=8 --rxq=8 --txq=8
+   port stop 0
+   port config 0 dcb vt off 4 pfc off
+   port start 0
+
+This configures 4 traffic classes with 2 queues per TC.
+
+PFC Configuration
+^^^^^^^^^^^^^^^^^
+
+Priority Flow Control (PFC) provides a mechanism to pause and resume traffic
+on individual traffic classes, enabling lossless Ethernet for specific priorities.
+
+PFC can be configured per priority using the ``rte_eth_dev_priority_flow_ctrl_set()`` API.
+Each traffic class can be independently configured with:
+
+* RX pause only
+* TX pause only
+* Full duplex pause
+* No pause (disabled)
+
+PFC operates in VLAN-based mode and requires DCB to be configured first.
+
+Features:
+
+* Per-TC pause control (XON/XOFF)
+* Configurable high/low watermarks for buffer management
+* Configurable pause quanta
+* PFC statistics exposed via xstats
+
+Example PFC configuration using DPDK API:
+
+.. code-block:: c
+
+   struct rte_eth_pfc_conf pfc_conf;
+
+   pfc_conf.fc.mode = RTE_ETH_FC_FULL;          /* Enable full duplex pause */
+   pfc_conf.fc.high_water = 100000;              /* High watermark in bytes */
+   pfc_conf.fc.low_water = 50000;                /* Low watermark in bytes */
+   pfc_conf.fc.pause_time = 0xFFFF;              /* Pause quanta (in 512 bit-time units) */
+   pfc_conf.priority = 0;                        /* Configure PFC for priority 0 */
+
+   ret = rte_eth_dev_priority_flow_ctrl_set(port_id, &pfc_conf);
+
 Tx Packet Pacing
 ~~~~~~~~~~~~~~~~
 
diff --git a/doc/guides/rel_notes/release_25_11.rst b/doc/guides/rel_notes/release_25_11.rst
index c5ba335cfc..6a35f9f15d 100644
--- a/doc/guides/rel_notes/release_25_11.rst
+++ b/doc/guides/rel_notes/release_25_11.rst
@@ -115,6 +115,10 @@ New Features
 
   Added network driver for the Huawei SPx series Network Adapters.
 
+* **Added DCB and PFC support to Intel ice net driver.**
+
+  Added support for Data Center Bridging (DCB) and Priority Flow Control (PFC) to the Intel ice PMD.
+
 * **Added Nebulamatrix nbl ethernet driver.**
 
   Added the PMD for Nebulamatrix NICs.
-- 
2.43.0