diff --git a/src/include/ipc4/fw_reg.h b/src/include/ipc4/fw_reg.h
index 1c47e8f00..732de5060 100644
--- a/src/include/ipc4/fw_reg.h
+++ b/src/include/ipc4/fw_reg.h
@@ -17,7 +17,10 @@
 
 /**
  * \file include/ipc4/fw_reg.h
- * \brief IPC4 fw registers in mailbox for host
+ * \brief IPC4 fw registers in mailbox for host. Fw exposes dsp / fw
+ * state information to the host via shared memory window 0, .e.g. fw error,
+ * pipeline state, dma llp counter and others. These information are included
+ * in ipc4_fw_registers structure defined in this file.
  * NOTE: This ABI uses bit fields and is non portable.
  */