diff --git a/docs/source/rb/index.rst b/docs/source/rb/index.rst
index b5c5d4f79..78b57d0c3 100644
--- a/docs/source/rb/index.rst
+++ b/docs/source/rb/index.rst
@@ -81,7 +81,7 @@ The NIC register space is constructed from a linked list of register blocks.  Ea
     0x0000C060  0x00000100  :ref:`rb_tdma_sch`
     0x0000C080  0x00000100  :ref:`rb_phc`
     0x0000C081  0x00000100  :ref:`rb_phc_perout`
-    0x0000C090  0x00000100  RX queue map
+    0x0000C090  0x00000100  :ref:`rb_rx_queue_map`
     0x0000C100  0x00000100  :ref:`rb_gpio`
     0x0000C110  0x00000100  :ref:`rb_i2c`
     0x0000C120  0x00000200  :ref:`rb_flash_spi`
diff --git a/docs/source/rb/rx_queue_map.rst b/docs/source/rb/rx_queue_map.rst
new file mode 100644
index 000000000..f674e4773
--- /dev/null
+++ b/docs/source/rb/rx_queue_map.rst
@@ -0,0 +1,83 @@
+.. _rb_rx_queue_map:
+
+===========================
+RX queue map register block
+===========================
+
+The RX queue map register block has a header with type 0x0000C090, version 0x00000100, and is used to control the mapping of packets into RX queues.
+
+.. table::
+
+    ============  =============  ======  ======  ======  ======  =============
+    Address       Field          31..24  23..16  15..8   7..0    Reset value
+    ============  =============  ======  ======  ======  ======  =============
+    RBB+0x00      Type           Vendor ID       Type            RO 0x0000C090
+    ------------  -------------  --------------  --------------  -------------
+    RBB+0x04      Version        Major   Minor   Patch   Meta    RO 0x00000100
+    ------------  -------------  ------  ------  ------  ------  -------------
+    RBB+0x08      Next pointer   Pointer to next register block  RO -
+    ------------  -------------  ------------------------------  -------------
+    RBB+0x0C      Ports          Port count                      RO -
+    ------------  -------------  ------------------------------  -------------
+    RBB+0x10+16n  Port offset    Port offset                     RW 0x00000000
+    ------------  -------------  ------------------------------  -------------
+    RBB+0x14+16n  Port RSS mask  Port RSS mask                   RW 0x00000000
+    ------------  -------------  ------------------------------  -------------
+    RBB+0x18+16n  Port app mask  Port app mask                   RW 0x00000000
+    ============  =============  ==============================  =============
+
+See :ref:`rb_overview` for definitions of the standard register block header fields.
+
+There is one set of registers per port, with the source port for each packet determined by the ``tid`` field, which is set in the RX FIFO subsystem to identify the source port when data is aggregated from multiple ports.  For each packet, the ``tdest`` field (provided by custom logic in the application section) and flow hash (computed in :ref:`mod_rx_hash` in :ref:`mod_mqnic_ingress`) are combined according to::
+
+    queue_index = (tdest & app_mask[tid]) + (rss_hash & rss_mask[tid]) + offset[tid]
+
+The goal of this setup is to enable any combination of flow hashing and custom application logic to influence queue selection, under the direction of host software.
+
+.. object:: Port count
+
+    The port count field contains the number of ports.
+
+    .. table::
+
+        ========  ======  ======  ======  ======  =============
+        Address   31..24  23..16  15..8   7..0    Reset value
+        ========  ======  ======  ======  ======  =============
+        RBB+0x0C  Port count                      RO -
+        ========  ==============================  =============
+
+.. object:: Port offset
+
+    The port offset field contains a fixed offset for the destination queue.
+
+    .. table::
+
+        ============  ======  ======  ======  ======  =============
+        Address       31..24  23..16  15..8   7..0    Reset value
+        ============  ======  ======  ======  ======  =============
+        RBB+0x10+16n  Port offset                     RW 0x00000000
+        ============  ==============================  =============
+
+.. object:: Port RSS mask
+
+    The port RSS mask field contains a mask value to select a portion of the RSS flow hash.
+
+    .. table::
+
+        ============  ======  ======  ======  ======  =============
+        Address       31..24  23..16  15..8   7..0    Reset value
+        ============  ======  ======  ======  ======  =============
+        RBB+0x14+16n  Port RSS mask                   RW 0x00000000
+        ============  ==============================  =============
+
+.. object:: Port app mask
+
+    The port app mask field contains a mask value to select a portion of the application-provided ``tdest`` value.
+
+    .. table::
+
+        ============  ======  ======  ======  ======  =============
+        Address       31..24  23..16  15..8   7..0    Reset value
+        ============  ======  ======  ======  ======  =============
+        RBB+0x18+16n  Port app mask                   RW 0x00000000
+        ============  ==============================  =============