docs(nvs): Document nvs_check.py functions

components/nvs_flash/nvs_partition_tool/nvs_check.py

@@ -22,6 +22,22 @@ blob_chunks: List[NVS_Entry] = []
 
 
 def check_partition_size(nvs_partition: NVS_Partition, nvs_log: NVS_Logger) -> bool:
+    """ Checks if the partition is large enough and has enough pages
+    """
+    if len(nvs_partition.raw_data) / 0x1000 < 3:
+        nvs_log.info(
+            nvs_log.yellow(
+                'NVS Partition size must be at least 0x3000 (4kiB * 3 pages == 12kiB)!'
+            )
+        )
+        return False
+    if len(nvs_partition.raw_data) % 0x1000 != 0:
+        nvs_log.info(
+            nvs_log.yellow(
+                'NVS Partition size must be a multiple of 0x1000 (4kiB)!'
+            )
+        )
+        return False
     if len(nvs_partition.pages) < 3:
         nvs_log.info(
             nvs_log.yellow(
@@ -83,16 +99,22 @@ def check_page_crc(nvs_page: NVS_Page, nvs_log: NVS_Logger) -> bool:
         return False
 
 
-def identify_entry_duplicates(entry: NVS_Entry, seen_written_entires: Dict[str, List[NVS_Entry]]) -> Dict[str, List[NVS_Entry]]:
+def identify_entry_duplicates(entry: NVS_Entry, entry_dict: Dict[str, List[NVS_Entry]]) -> Dict[str, List[NVS_Entry]]:
+    """Identifies and logs written entries
+
+    Part 1 of duplicate entry check mechanism
+    """
     if entry.state == 'Written':
-        if entry.key in seen_written_entires:
-            seen_written_entires[entry.key].append(entry)
+        if entry.key in entry_dict:
+            entry_dict[entry.key].append(entry)
         else:
-            seen_written_entires[entry.key] = [entry]
-    return seen_written_entires
+            entry_dict[entry.key] = [entry]
+    return entry_dict
 
 
 def check_page_entries(nvs_page: NVS_Page, nvs_log: NVS_Logger) -> Dict[str, List[NVS_Entry]]:
+    """Checks entries in the given page (entry state, children CRC32, entry type, span and gathers blobs and namespaces)
+    """
     seen_written_entires: Dict[str, List[NVS_Entry]] = {}
 
     for entry in nvs_page.entries:
@@ -203,6 +225,11 @@ def check_page_entries(nvs_page: NVS_Page, nvs_log: NVS_Logger) -> Dict[str, Lis
 
 
 def filter_namespaces_fake_duplicates(duplicate_entries_dict: Dict[str, List[NVS_Entry]]) -> Dict[str, List[NVS_Entry]]:
+    """Takes a dictionary of entries (as written) and returns a new dictionary with "fake" duplicates,
+    where entries which have the same key but under different namespaces are filtered out
+
+    Use `filter_entry_duplicates()` to properly filter out all duplicates
+    """
     new_duplicate_entries_dict: Dict[str, List[NVS_Entry]] = {}
     for key, duplicate_entries in duplicate_entries_dict.items():
         seen_entries: List[NVS_Entry] = []
@@ -237,6 +264,11 @@ def filter_namespaces_fake_duplicates(duplicate_entries_dict: Dict[str, List[NVS
 
 
 def filter_blob_related_duplicates(duplicate_entries_dict: Dict[str, List[NVS_Entry]]) -> Dict[str, List[NVS_Entry]]:
+    """Takes a dictionary of entries (as written) and returns a new dictionary with "fake" duplicates,
+    where entries related to blob index and blob data under the same namespace are filtered out
+
+    Use `filter_entry_duplicates()` to properly filter out all duplicates
+    """
     new_duplicate_entries_dict: Dict[str, List[NVS_Entry]] = {}
     for key, duplicate_entries in duplicate_entries_dict.items():
         seen_blob_index: List[NVS_Entry] = []
@@ -298,9 +330,19 @@ def filter_blob_related_duplicates(duplicate_entries_dict: Dict[str, List[NVS_En
     return new_duplicate_entries_dict
 
 
-def filter_entry_duplicates(seen_written_entires: Dict[str, List[NVS_Entry]]) -> Dict[str, List[NVS_Entry]]:
-    duplicate_entries_list = {key: v for key, v in seen_written_entires.items() if len(v) > 1}
+def filter_entry_duplicates(entries: Dict[str, List[NVS_Entry]]) -> Dict[str, List[NVS_Entry]]:
+    """Takes a dictionary of (seen written) entries and outputs a new dictionary with "fake" duplicates filtered out, keeping only real duplicates in
+
+    (i.e. duplicate keys under different namespaces and blob index and blob data having the same key under the same namespace are allowed
+    and should be filtered out)
+
+    Part 2 of duplicate entry check mechanism
+    """
+    # Only keep seen written entries which have been observerd multiple times (duplicates)
+    duplicate_entries_list = {key: v for key, v in entries.items() if len(v) > 1}
+    # Filter out "fake" duplicates 1 (duplicate keys under different namespaces are allowed)
     duplicate_entries_list_1 = filter_namespaces_fake_duplicates(duplicate_entries_list)
+    # Filter out "fake" duplicates 2 (blob index and blob data are allowed to have the same key even in the same namespace)
     duplicate_entries_list_2 = filter_blob_related_duplicates(duplicate_entries_list_1)
     return duplicate_entries_list_2
 
@@ -341,6 +383,8 @@ def print_entry_duplicates(duplicate_entries_list: Dict[str, List[NVS_Entry]], n
 
 
 def assemble_blobs(nvs_log: NVS_Logger) -> None:
+    """Assembles blob data from blob chunks
+    """
     for chunk in blob_chunks:
         # chunk: NVS_Entry
         parent = blobs.get(
@@ -361,6 +405,8 @@ def assemble_blobs(nvs_log: NVS_Logger) -> None:
 
 
 def check_blob_data(nvs_log: NVS_Logger) -> None:
+    """Checks blob data for missing chunks or data
+    """
     for blob_key in blobs:
         blob_index = blobs[blob_key][0]
         blob_chunks = blobs[blob_key][1:]
@@ -395,6 +441,8 @@ def check_blobs(nvs_log: NVS_Logger) -> None:
 
 
 def check_namespaces(nvs_log: NVS_Logger) -> None:
+    """Checks namespaces (entries using undefined namespace indexes, unused namespaces)
+    """
     # Undefined namespace index check
     for used_ns in used_namespaces:
         key = found_namespaces.pop(used_ns, None)
@@ -415,6 +463,9 @@ def check_namespaces(nvs_log: NVS_Logger) -> None:
 
 
 def reset_global_variables() -> None:
+    """Global variables need to be cleared out before calling `integrity_check()` multiple times from a script
+    (e.g. when running tests) to avoid incorrect output
+    """
     global used_namespaces, found_namespaces, blobs, blob_chunks
     used_namespaces = {}
     found_namespaces = {}
@@ -423,6 +474,8 @@ def reset_global_variables() -> None:
 
 
 def integrity_check(nvs_partition: NVS_Partition, nvs_log: NVS_Logger) -> None:
+    """Function for multi-stage integrity check of a NVS partition
+    """
     # Partition size check
     check_partition_size(nvs_partition, nvs_log)
 
@@ -431,18 +484,19 @@ def integrity_check(nvs_partition: NVS_Partition, nvs_log: NVS_Logger) -> None:
 
     seen_written_entires_all: Dict[str, List[NVS_Entry]] = {}
 
+    # Loop through all pages in the partition
     for page in nvs_partition.pages:
         # page: NVS_Page
 
-        # Print page header
+        # Print a page header
         if page.header['status'] == 'Empty':
-            # Check if page is truly empty
+            # Check if a page is truly empty
             check_empty_page_content(page, nvs_log)
         else:
-            # Check page header CRC32
+            # Check a page header CRC32
             check_page_crc(page, nvs_log)
 
-        # Check all entries
+        # Check all entries in a page
         seen_written_entires = check_page_entries(page, nvs_log)
 
         # Collect all seen written entries