fast_pair: Remove MRAM1x dependency for targets without Partition Manager

Removes MRAM1x dependency for targets without Partition Manager.
The absolute Fast Pair partition address is now calculated by
getting address of Fast Pair partition grandparent and adding it
to Fast Pair partition relative address. Fast Pair partition
grandparent node is a NVM node the partition resides in.

Jira: NCSDK-29847

Signed-off-by: Aleksander Strzebonski <[email protected]>

Author: alstrzebonski

cmake/sysbuild/fast_pair_hex.cmake

@@ -47,6 +47,18 @@ function(fast_pair_hex_pm)
     )
 endfunction()
 
+# This function should probably one day be moved to some common utilities file.
+function(dt_get_parent parent_full_path node_full_path)
+  string(FIND "${node_full_path}" "/" pos REVERSE)
+
+  if(pos LESS_EQUAL 0)
+    message(FATAL_ERROR "Unable to get parent of node: ${node_full_path}")
+  endif()
+
+  string(SUBSTRING "${node_full_path}" 0 ${pos} parent)
+  set(${parent_full_path} ${parent} PARENT_SCOPE)
+endfunction()
+
 function(fast_pair_hex_dts)
   include(${CMAKE_CURRENT_LIST_DIR}/suit_utilities.cmake)
 
@@ -58,31 +70,47 @@ function(fast_pair_hex_dts)
   set(fp_partition_name bt_fast_pair_partition)
 
   sysbuild_dt_nodelabel(
-    bt_fast_pair_partition_nodelabel
+    bt_fast_pair_partition_node_full_path
     IMAGE
     ${DEFAULT_IMAGE}
     NODELABEL
     "${fp_partition_name}"
     )
+
   sysbuild_dt_reg_addr(
     bt_fast_pair_partition_relative_address
     IMAGE
     ${DEFAULT_IMAGE}
     PATH
-    "${bt_fast_pair_partition_nodelabel}"
+    "${bt_fast_pair_partition_node_full_path}"
     )
 
-  # This part assumes that the Fast Pair partition resides in MRAM1x.
-  # TODO: Rewrite it to be more generic and support other memory regions.
-  sysbuild_dt_nodelabel(mram1x_nodelabel IMAGE ${DEFAULT_IMAGE} NODELABEL "mram1x")
-  sysbuild_dt_reg_addr(mram1x_address IMAGE ${DEFAULT_IMAGE} PATH "${mram1x_nodelabel}")
+  # It's assumed that the Fast Pair partition node is a child of an address-less node which groups
+  # partitions and is a child of a NVM node. For more details see the Fixed flash partitions section
+  # of https://docs.zephyrproject.org/latest/build/dts/intro-syntax-structure.html#unit-addresses.
+  dt_get_parent(
+    bt_fast_pair_partition_node_parent_full_path
+    "${bt_fast_pair_partition_node_full_path}"
+    )
+  dt_get_parent(
+    nvm_node_full_path
+    "${bt_fast_pair_partition_node_parent_full_path}"
+    )
+  sysbuild_dt_reg_addr(
+    nvm_base_address
+    IMAGE
+    ${DEFAULT_IMAGE}
+    PATH
+    "${nvm_node_full_path}"
+    )
 
   math(
     EXPR
     bt_fast_pair_partition_address
-    "${mram1x_address} + ${bt_fast_pair_partition_relative_address}"
+    "${nvm_base_address} + ${bt_fast_pair_partition_relative_address}"
     OUTPUT_FORMAT
-    HEXADECIMAL)
+    HEXADECIMAL
+    )
 
   set(
     fp_provisioning_data_hex

subsys/bluetooth/services/fast_pair/fp_registration_data.c

@@ -22,6 +22,7 @@ LOG_MODULE_DECLARE(fast_pair, CONFIG_BT_FAST_PAIR_LOG_LEVEL);
 #define FP_PARTITION_ID		PM_BT_FAST_PAIR_ID
 #define FP_PARTITION_SIZE	PM_BT_FAST_PAIR_SIZE
 #else
+BUILD_ASSERT(FIXED_PARTITION_EXISTS(bt_fast_pair_partition));
 #define FP_PARTITION_ID		FIXED_PARTITION_ID(bt_fast_pair_partition)
 #define FP_PARTITION_SIZE	FIXED_PARTITION_SIZE(bt_fast_pair_partition)
 #endif