settings: add ZMS legacy backend for backward compatibility

rghaddab · rghaddab · commit 26673e769fbc · 2025-04-12T13:41:09.000+02:00
The legacy ZMS backend is needed by some applications that need to
maintain their backward compatibility.

Signed-off-by: Riadh Ghaddab &lt;rghaddab@baylibre.com&gt;
diff --git a/CODEOWNERS b/CODEOWNERS
@@ -818,6 +818,7 @@
 /subsys/partition_manager/                @nordicjm @tejlmand
 /subsys/pcd/                              @nrfconnect/ncs-pluto
 /subsys/sdfw_services/                    @nrfconnect/ncs-aurora
+/subsys/settings/                         @nrfconnect/ncs-pluto @rghaddab
 /subsys/sdfw_services/services/extmem/    @nrfconnect/ncs-charon
 /subsys/sdfw_services/services/suit_service/ @nrfconnect/ncs-charon
 /subsys/shell/                            @nordic-krch
diff --git a/include/flash_map_pm.h b/include/flash_map_pm.h
@@ -30,7 +30,7 @@
 #define image_scratch mcuboot_scratch
 
 #if (CONFIG_SETTINGS_FCB || CONFIG_SETTINGS_NVS || defined(PM_SETTINGS_STORAGE_ID) ||\
-	CONFIG_SETTINGS_ZMS)
+	CONFIG_SETTINGS_ZMS || CONFIG_SETTINGS_ZMS_LEGACY)
 #define storage settings_storage
 #define storage_partition settings_storage
 #elif CONFIG_FILE_SYSTEM_LITTLEFS
diff --git a/samples/common/mcumgr_bt_ota_dfu/Kconfig b/samples/common/mcumgr_bt_ota_dfu/Kconfig
@@ -68,15 +68,15 @@ config MCUMGR_GRP_OS_MCUMGR_PARAMS
 
 endif # MCUMGR_TRANSPORT_BT_REASSEMBLY
 
-if (SETTINGS_FCB || SETTINGS_NVS || SETTINGS_ZMS)
+if (SETTINGS_FCB || SETTINGS_NVS || SETTINGS_ZMS || SETTINGS_ZMS_LEGACY)
 
 config MCUMGR_GRP_ZBASIC
 	default y
 
 config MCUMGR_GRP_ZBASIC_STORAGE_ERASE
 	default y
 
-endif # (SETTINGS_FCB || SETTINGS_NVS || SETTINGS_ZMS)
+endif # (SETTINGS_FCB || SETTINGS_NVS || SETTINGS_ZMS || SETTINGS_ZMS_LEGACY)
 
 if NORDIC_QSPI_NOR
 
diff --git a/samples/matter/common/src/persistent_storage/persistent_storage_shell.cpp b/samples/matter/common/src/persistent_storage/persistent_storage_shell.cpp
@@ -8,7 +8,7 @@
 
 #if defined(CONFIG_SETTINGS_NVS)
 #include <zephyr/fs/nvs.h>
-#elif defined(CONFIG_SETTINGS_ZMS)
+#elif defined(CONFIG_SETTINGS_ZMS) || defined(CONFIG_SETTINGS_ZMS_LEGACY)
 #include <zephyr/fs/zms.h>
 #endif
 #include <zephyr/settings/settings.h>
@@ -20,7 +20,7 @@ namespace
 {
 #if defined(CONFIG_SETTINGS_NVS)
 nvs_fs *sStorage = nullptr;
-#elif defined(CONFIG_SETTINGS_ZMS)
+#elif defined(CONFIG_SETTINGS_ZMS) || defined(CONFIG_SETTINGS_ZMS_LEGACY)
 zms_fs *sStorage = nullptr;
 #endif
 
@@ -34,7 +34,7 @@ int CalculateFreeSpace()
 {
 #if defined(CONFIG_SETTINGS_NVS)
 	return nvs_calc_free_space(sStorage);
-#elif defined(CONFIG_SETTINGS_ZMS)
+#elif defined(CONFIG_SETTINGS_ZMS) || defined(CONFIG_SETTINGS_ZMS_LEGACY)
 	return zms_calc_free_space(sStorage);
 #endif
 }
@@ -135,7 +135,7 @@ bool PersistentStorageShell::Init()
 
 #if defined(CONFIG_SETTINGS_NVS)
 	sStorage = reinterpret_cast<nvs_fs *>(storage);
-#elif defined(CONFIG_SETTINGS_ZMS)
+#elif defined(CONFIG_SETTINGS_ZMS) || defined(CONFIG_SETTINGS_ZMS_LEGACY)
 	sStorage = reinterpret_cast<zms_fs *>(storage);
 #endif
 
diff --git a/samples/matter/lock/src/access/access_storage.cpp b/samples/matter/lock/src/access/access_storage.cpp
@@ -13,7 +13,7 @@
 #ifdef CONFIG_LOCK_PRINT_STORAGE_STATUS
 #ifdef CONFIG_SETTINGS_NVS
 #include <zephyr/fs/nvs.h>
-#elif CONFIG_SETTINGS_ZMS
+#elif CONFIG_SETTINGS_ZMS || CONFIG_SETTINGS_ZMS_LEGACY
 #include <zephyr/fs/zms.h>
 #endif /* CONFIG_SETTINGS_NVS */
 #include <zephyr/logging/log.h>
@@ -33,7 +33,7 @@ bool GetStorageFreeSpace(size_t &freeBytes)
 	}
 #ifdef CONFIG_SETTINGS_NVS
 	freeBytes = nvs_calc_free_space(static_cast<nvs_fs *>(storage));
-#elif CONFIG_SETTINGS_ZMS
+#elif CONFIG_SETTINGS_ZMS || CONFIG_SETTINGS_ZMS_LEGACY
 	freeBytes = zms_calc_free_space(static_cast<zms_fs *>(storage));
 #endif /* CONFIG_SETTINGS_NVS */
 	return true;
diff --git a/scripts/ci/license_allow_list.yaml b/scripts/ci/license_allow_list.yaml
@@ -48,6 +48,7 @@ Apache-2.0: |
   ^nrf/modules/openthread/
   ^nrf/samples/net/http_server/src/main.c
   ^nrf/tests/subsys/suit/common/tls_config/user-tls-conf.h
+  ^nrf/subsys/settings/
 curl: "^nrf/ext/"
 MIT: "^nrf/ext/"
 BSD-3-CLAUSE: |
diff --git a/subsys/CMakeLists.txt b/subsys/CMakeLists.txt
@@ -68,3 +68,4 @@ add_subdirectory_ifdef(CONFIG_MGMT_SUITFU mgmt/suitfu)
 add_subdirectory_ifdef(CONFIG_DULT dult)
 add_subdirectory_ifdef(CONFIG_NRF_COMPRESS nrf_compress)
 add_subdirectory(mgmt/mcumgr)
+add_subdirectory_ifdef(CONFIG_SETTINGS settings)
diff --git a/subsys/Kconfig b/subsys/Kconfig
@@ -43,4 +43,5 @@ rsource "suit/Kconfig"
 rsource "dult/Kconfig"
 rsource "nrf_compress/Kconfig"
 rsource "mcuboot_ids/Kconfig"
+rsource "settings/Kconfig"
 endmenu
diff --git a/subsys/partition_manager/CMakeLists.txt b/subsys/partition_manager/CMakeLists.txt
@@ -53,7 +53,7 @@ if (CONFIG_BOARD_HAS_NRF5_BOOTLOADER)
   ncs_add_partition_manager_config(pm.yml.nrf5_mbr)
 endif()
 
-if (CONFIG_SETTINGS_FCB OR CONFIG_SETTINGS_NVS OR CONFIG_SETTINGS_ZMS)
+if (CONFIG_SETTINGS_FCB OR CONFIG_SETTINGS_NVS OR CONFIG_SETTINGS_ZMS OR CONFIG_SETTINGS_ZMS_LEGACY)
   ncs_add_partition_manager_config(pm.yml.settings)
 endif()
 
@@ -65,7 +65,7 @@ if (CONFIG_NVS AND NOT CONFIG_SETTINGS_NVS)
   ncs_add_partition_manager_config(pm.yml.nvs)
 endif()
 
-if (CONFIG_ZMS AND NOT CONFIG_SETTINGS_ZMS)
+if (CONFIG_ZMS AND NOT (CONFIG_SETTINGS_ZMS OR CONFIG_SETTINGS_ZMS_LEGACY))
   ncs_add_partition_manager_config(pm.yml.zms)
 endif()
 
diff --git a/subsys/partition_manager/Kconfig b/subsys/partition_manager/Kconfig
@@ -53,7 +53,7 @@ rsource "Kconfig.template.partition_region"
 endif
 
 
-if SETTINGS_FCB || SETTINGS_NVS || SETTINGS_ZMS
+if SETTINGS_FCB || SETTINGS_NVS || SETTINGS_ZMS || SETTINGS_ZMS_LEGACY
 partition=SETTINGS_STORAGE
 partition-size=0x2000
 rsource "Kconfig.template.partition_config"
@@ -75,7 +75,7 @@ rsource "Kconfig.template.partition_config"
 rsource "Kconfig.template.partition_region"
 endif
 
-if ZMS && !SETTINGS_ZMS
+if ZMS && !(SETTINGS_ZMS || SETTINGS_ZMS_LEGACY)
 partition=ZMS_STORAGE
 partition-size=0x6000
 rsource "Kconfig.template.partition_config"
diff --git a/subsys/settings/CMakeLists.txt b/subsys/settings/CMakeLists.txt
@@ -0,0 +1,10 @@
+#
+# Copyright (c) 2025 Nordic Semiconductor
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+
+add_subdirectory(src)
+zephyr_include_directories(
+  include
+  )
diff --git a/subsys/settings/Kconfig b/subsys/settings/Kconfig
@@ -0,0 +1,48 @@
+#
+# Copyright (c) 2025 Nordic Semiconductor
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+
+choice SETTINGS_BACKEND
+
+config SETTINGS_ZMS_LEGACY
+	bool "Settings ZMS legacy backend [DEPRECATED]"
+	depends on ZMS
+	select DEPRECATED
+	help
+	  Use the legacy backend of ZMS for Settings
+
+endchoice
+
+if SETTINGS_ZMS_LEGACY
+
+config SETTINGS_ZMS_NAME_CACHE
+	bool "ZMS name lookup cache"
+	select SYS_HASH_FUNC32
+	help
+	  Enable ZMS name lookup cache, used to reduce the Settings name
+	  lookup time.
+
+config SETTINGS_ZMS_NAME_CACHE_SIZE
+	int "ZMS name lookup cache size"
+	default 128
+	range 1 $(UINT32_MAX)
+	depends on SETTINGS_ZMS_NAME_CACHE
+	help
+	  Number of entries in Settings ZMS name cache.
+
+config SETTINGS_ZMS_SECTOR_SIZE_MULT
+	int "Sector size of the ZMS settings area"
+	default 1
+	help
+	  The sector size to use for the ZMS settings area as a multiple of
+	  FLASH_ERASE_BLOCK_SIZE.
+
+config SETTINGS_ZMS_SECTOR_COUNT
+	int "Sector count of the ZMS settings area"
+	default 8
+	help
+	  Number of sectors used for the ZMS settings area
+
+endif # SETTINGS_ZMS_LEGACY
diff --git a/subsys/settings/include/settings/settings_zms_legacy.h b/subsys/settings/include/settings/settings_zms_legacy.h
@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2024 BayLibre SAS
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef __SETTINGS_ZMS_LEGACY_H_
+#define __SETTINGS_ZMS_LEGACY_H_
+
+#include <zephyr/fs/zms.h>
+#include <zephyr/settings/settings.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* In the ZMS backend, each setting is stored in two ZMS entries:
+ *	1. setting's name
+ *	2. setting's value
+ *
+ * The ZMS entry ID for the setting's value is determined implicitly based on
+ * the ID of the ZMS entry for the setting's name, once that is found. The
+ * difference between name and value ID is constant and equal to
+ * ZMS_NAME_ID_OFFSET.
+ *
+ * Setting's name entries start from ZMS_NAMECNT_ID + 1.
+ * The entry with ID == ZMS_NAMECNT_ID is used to store the largest name ID in use.
+ *
+ * Deleted records will not be found, only the last record will be read.
+ */
+#define ZMS_NAMECNT_ID     0x80000000
+#define ZMS_NAME_ID_OFFSET 0x40000000
+
+#define SETTINGS_FULL_NAME_LEN SETTINGS_MAX_NAME_LEN + SETTINGS_EXTRA_LEN + 1
+
+struct settings_zms {
+	struct settings_store cf_store;
+	struct zms_fs cf_zms;
+	uint32_t last_name_id;
+	const struct device *flash_dev;
+#if CONFIG_SETTINGS_ZMS_NAME_CACHE
+	struct {
+		uint32_t name_hash;
+		uint32_t name_id;
+	} cache[CONFIG_SETTINGS_ZMS_NAME_CACHE_SIZE];
+
+	uint32_t cache_next;
+	uint32_t cache_total;
+	bool loaded;
+#endif
+};
+
+/* register zms to be a source of settings */
+int settings_zms_src(struct settings_zms *cf);
+
+/* register zms to be the destination of settings */
+int settings_zms_dst(struct settings_zms *cf);
+
+/* Initialize a zms backend. */
+int settings_zms_backend_init(struct settings_zms *cf);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __SETTINGS_ZMS_LEGACY_H_ */
diff --git a/subsys/settings/src/CMakeLists.txt b/subsys/settings/src/CMakeLists.txt
@@ -0,0 +1,7 @@
+#
+# Copyright (c) 2025 Nordic Semiconductor
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+
+zephyr_sources_ifdef(CONFIG_SETTINGS_ZMS_LEGACY settings_zms_legacy.c)
diff --git a/subsys/settings/src/settings_zms_legacy.c b/subsys/settings/src/settings_zms_legacy.c
diff --git a/subsys/trusted_storage/Kconfig b/subsys/trusted_storage/Kconfig
