subsys: settings: nvs: provisioning of settings images

boards/qemu/x86/Kconfig.defconfig

@@ -17,6 +17,9 @@ config QEMU_TARGET
 config HAS_COVERAGE_SUPPORT
  default y
 
+config X86_EXTRA_PAGE_TABLE_PAGES
+ default 1 if FLASH_SIMULATOR_SIZE > 0
+
 endif # BOARD_QEMU_X86 || BOARD_QEMU_X86_64 || BOARD_QEMU_X86_LAKEMONT || BOARD_QEMU_X86_TINY
 
 

boards/qemu/x86/board.cmake

@@ -79,10 +79,20 @@ endif()
 # debugserver: QEMU_EXTRA_FLAGS += -s -S
 # debugserver: qemu
 
-if(CONFIG_BOARD_QEMU_X86_TINY AND CONFIG_DEMAND_PAGING
- AND NOT CONFIG_LINKER_GENERIC_SECTIONS_PRESENT_AT_BOOT)
- # This is to map the flash so it is accessible.
- math(EXPR QEMU_FLASH_SIZE_KB "${CONFIG_FLASH_SIZE} * 1024")
- set(X86_EXTRA_GEN_MMU_ARGUMENTS
- --map ${CONFIG_FLASH_BASE_ADDRESS},${QEMU_FLASH_SIZE_KB},W)
+if(CONFIG_MMU)
+ if(CONFIG_BOARD_QEMU_X86_TINY AND CONFIG_DEMAND_PAGING
+ AND NOT CONFIG_LINKER_GENERIC_SECTIONS_PRESENT_AT_BOOT)
+ # This is to map the flash so it is accessible.
+ math(EXPR QEMU_FLASH_SIZE_KB "${CONFIG_FLASH_SIZE} * 1024")
+ set(X86_EXTRA_GEN_MMU_ARGUMENTS
+ --map ${CONFIG_FLASH_BASE_ADDRESS},${QEMU_FLASH_SIZE_KB},W)
+ endif()
+
+ if(DEFINED CONFIG_FLASH_SIMULATOR_BASE_ADDRESS
+ AND DEFINED CONFIG_FLASH_SIMULATOR_SIZE)
+
+ # Map the simulated flash to a memory file on QEMU targets.
+ set(X86_EXTRA_GEN_MMU_ARGUMENTS
+ --map ${CONFIG_FLASH_SIMULATOR_BASE_ADDRESS},${CONFIG_FLASH_SIMULATOR_SIZE},W)
+ endif()
 endif()

boards/qemu/x86/qemu_x86.dts

@@ -13,6 +13,10 @@
 #endif
 #define DT_FLASH_SIZE DT_SIZE_K(4096)
 
+/* Simulated Flash */
+#define DT_SIM_FLASH_BASE (DT_DRAM_BASE + DT_DRAM_SIZE - DT_SIZE_M(1))
+#define DT_SIM_FLASH_SIZE DT_SIZE_K(256)
+
 #include <intel/atom.dtsi>
 #include <zephyr/dt-bindings/pcie/pcie.h>
 
@@ -80,16 +84,29 @@
  };
  };
 
+ reserved-memory {
+ #address-cells = <1>;
+ #size-cells = <1>;
+
+ sim_flash_mem: memory@1f00000 {
+ compatible = "zephyr,memory-region";
+ reg = <DT_SIM_FLASH_BASE DT_SIM_FLASH_SIZE>;
+ zephyr,memory-region = "SOC_NV_FLASH";
+ };
+ };
+
  sim_flash: sim_flash {
  compatible = "zephyr,sim-flash";
 
  #address-cells = <1>;
  #size-cells = <1>;
  erase-value = <0xff>;
 
+ memory-region = <&sim_flash_mem>;
+
  flash_sim0: flash_sim@0 {
  compatible = "soc-nv-flash";
- reg = <0x00000000 DT_SIZE_K(1024)>;
+ reg = <DT_SIM_FLASH_BASE DT_SIM_FLASH_SIZE>;
 
  erase-block-size = <1024>;
  write-block-size = <4>;
@@ -147,22 +164,22 @@
  * Storage partition will be used by FCB/LittleFS/NVS
  * if enabled.
  */
- storage_partition: partition@1000 {
+ storage_partition: partition@0 {
  label = "storage";
- reg = <0x00001000 0x00010000>;
+ reg = <0x00000000 0x00010000>;
  };
 
- slot0_partition: partition@11000 {
+ slot0_partition: partition@10000 {
  label = "image-0";
- reg = <0x00011000 0x00010000>;
+ reg = <0x00010000 0x00010000>;
  };
- slot1_partition: partition@21000 {
+ slot1_partition: partition@20000 {
  label = "image-1";
- reg = <0x00021000 0x00010000>;
+ reg = <0x00020000 0x00010000>;
  };
- eepromemu_partition: partition@31000 {
+ eepromemu_partition: partition@30000 {
  label = "eeprom-emu";
- reg = <0x00031000 0x00010000>;
+ reg = <0x00030000 0x00010000>;
  };
  };
 };

cmake/emu/qemu.cmake

@@ -391,6 +391,12 @@ else()
  add_custom_target(qemu_nvme_disk)
 endif()
 
+if(CONFIG_FLASH_SIMULATOR_PROVISION)
+ list(APPEND QEMU_EXTRA_FLAGS
+ -device loader,file=${CMAKE_CURRENT_BINARY_DIR}/soc-nv-flash-image.hex
+ )
+endif()
+
 if(NOT QEMU_PIPE)
  set(QEMU_PIPE_COMMENT "\nTo exit from QEMU enter: 'CTRL+a, x'\n")
 endif()

drivers/flash/Kconfig.simulator

@@ -49,6 +49,26 @@ config FLASH_SIMULATOR_DOUBLE_WRITES
  In case when FLASH_SIMULATOR_EXPLICIT_ERASE is selected multiple writes to the same bit
  but only change from erase-value to opposite will be registered.
 
+config FLASH_SIMULATOR_PROVISION
+ bool "Initialize flash in QEMU from an image file to simulate provisioning."
+ help
+ This option maps simulated flash to a memory file on QEMU targets. This
+ file can be a pre-built binary image so that flash will be pre-populated.
+
+DT_COMPAT_Z_SIM_FLASH:=zephyr,sim-flash
+DT_NODELABEL_ENABLED_WITH_Z_SIM_FLASH:=$(dt_nodelabel_enabled_with_compat,sim_flash,$(DT_COMPAT_Z_SIM_FLASH))
+DT_NODELABEL_SIM_FLASH_MEMORY_REGION:=$(dt_node_ph_prop_path,$(dt_nodelabel_path,sim_flash),memory-region)
+
+config FLASH_SIMULATOR_BASE_ADDRESS
+ hex
+ depends on $(DT_NODELABEL_ENABLED_WITH_Z_SIM_FLASH)
+ default $(dt_node_reg_addr_hex,$(DT_NODELABEL_SIM_FLASH_MEMORY_REGION))
+
+config FLASH_SIMULATOR_SIZE
+ int
+ depends on $(DT_NODELABEL_ENABLED_WITH_Z_SIM_FLASH)
+ default $(dt_node_reg_size_int,$(DT_NODELABEL_SIM_FLASH_MEMORY_REGION))
+
 config FLASH_SIMULATOR_SIMULATE_TIMING
  bool "Hardware timing simulation"
 

drivers/flash/flash_simulator.c

@@ -48,7 +48,7 @@
 #error "Erase unit must be a multiple of program unit"
 #endif
 
-#define MOCK_FLASH(addr) (mock_flash + (addr) - FLASH_SIMULATOR_BASE_OFFSET)
+#define MOCK_FLASH(offset) (mock_flash + (offset))
 
 /* maximum number of pages that can be tracked by the stats module */
 #define STATS_PAGE_COUNT_THRESHOLD 256
@@ -148,6 +148,9 @@ static bool flash_erase_at_start;
 static bool flash_rm_at_exit;
 static bool flash_in_ram;
 #else
+#if CONFIG_FLASH_SIMULATOR_PROVISION
+static uint8_t *mock_flash = (uint8_t *)FLASH_SIMULATOR_BASE_OFFSET;
+#else
 #if DT_NODE_HAS_PROP(DT_PARENT(SOC_NV_FLASH_NODE), memory_region)
 #define FLASH_SIMULATOR_MREGION \
  LINKER_DT_NODE_REGION_NAME( \
@@ -156,6 +159,7 @@ static uint8_t mock_flash[FLASH_SIMULATOR_FLASH_SIZE] Z_GENERIC_SECTION(FLASH_SI
 #else
 static uint8_t mock_flash[FLASH_SIMULATOR_FLASH_SIZE];
 #endif
+#endif /* CONFIG_FLASH_SIMULATOR_PROVISION */
 #endif /* CONFIG_ARCH_POSIX */
 
 static const struct flash_driver_api flash_sim_api;
@@ -174,9 +178,9 @@ static int flash_range_is_valid(const struct device *dev, off_t offset,
  size_t len)
 {
  ARG_UNUSED(dev);
- if ((offset + len > FLASH_SIMULATOR_FLASH_SIZE +
-  FLASH_SIMULATOR_BASE_OFFSET) ||
- (offset < FLASH_SIMULATOR_BASE_OFFSET)) {
+
+ if ((offset < 0 || offset >= FLASH_SIMULATOR_FLASH_SIZE ||
+  (FLASH_SIMULATOR_FLASH_SIZE - offset) < len)) {
  return 0;
  }
 
@@ -299,8 +303,7 @@ static int flash_sim_write(const struct device *dev, const off_t offset,
 
 static void unit_erase(const uint32_t unit)
 {
- const off_t unit_addr = FLASH_SIMULATOR_BASE_OFFSET +
- (unit * FLASH_SIMULATOR_ERASE_UNIT);
+ const off_t unit_addr = unit * FLASH_SIMULATOR_ERASE_UNIT;
 
  /* erase the memory unit by setting it to erase value */
  memset(MOCK_FLASH(unit_addr), FLASH_SIMULATOR_ERASE_VALUE,
@@ -332,8 +335,7 @@ static int flash_sim_erase(const struct device *dev, const off_t offset,
  }
 #endif
  /* the first unit to be erased */
- uint32_t unit_start = (offset - FLASH_SIMULATOR_BASE_OFFSET) /
- FLASH_SIMULATOR_ERASE_UNIT;
+ uint32_t unit_start = offset / FLASH_SIMULATOR_ERASE_UNIT;
 
  /* erase as many units as necessary and increase their erase counter */
  for (uint32_t i = 0; i < len / FLASH_SIMULATOR_ERASE_UNIT; i++) {
@@ -417,7 +419,9 @@ static int flash_mock_init(const struct device *dev)
 static int flash_mock_init(const struct device *dev)
 {
  ARG_UNUSED(dev);
- memset(mock_flash, FLASH_SIMULATOR_ERASE_VALUE, ARRAY_SIZE(mock_flash));
+ if (!IS_ENABLED(CONFIG_FLASH_SIMULATOR_PROVISION)) {
+ memset(mock_flash, FLASH_SIMULATOR_ERASE_VALUE, FLASH_SIMULATOR_FLASH_SIZE);
+ }
  return 0;
 }
 #endif /* DT_NODE_HAS_PROP(DT_PARENT(SOC_NV_FLASH_NODE), memory_region) */

include/zephyr/arch/x86/ia32/linker.ld

@@ -573,7 +573,10 @@ SECTIONS
  .strtab 0 : { *(.strtab) }
  .shstrtab 0 : { *(.shstrtab) }
 #endif
- }
+
+ /* Sections generated from 'zephyr,memory-region' nodes */
+ LINKER_DT_SECTIONS()
+}
 
 #ifdef CONFIG_XIP
 /*

include/zephyr/kernel/internal/mm.h

@@ -74,6 +74,9 @@
 #ifdef CONFIG_XIP
 #error "XIP and a virtual memory kernel are not allowed"
 #endif
+#ifdef CONFIG_FLASH_SIMULATOR_PROVISION
+#error "Simulated flash memory cannot be provisioned for a virtual memory kernel."
+#endif
 #endif
 
 #ifndef _ASMLANGUAGE

samples/subsys/settings/README.rst

@@ -100,3 +100,60 @@ Sample Output
  <gamma> = 0 (default)
  save <gamma> key directly: OK.
  ...
+
+Provisioning of Settings
+************************
+
+Settings will often have to be provisioned separately from the application
+itself, e.g. because the settings are specific to a particular device or because
+the settings are sensitive and should not be included in the application binary.
+
+The settings subsystem supports this use case by allowing settings to be
+provisioned from a separate image.
+
+To demonstrate this feature, the sample can be built with the
+``CONFIG_FLASH_SIMULATOR_PROVISION`` option on QEMU. This will simulate a flash
+partition with a fixed memory layout and load the settings from a separate image
+at runtime into QEMU memory.
+
+To build and run the sample on QEMU, follow these steps:
+
+1. Build the sample for the qemu_x86 board with the default settings from
+ qemu_x86.conf (i.e. with the NVS settings backend enabled.) and this
+ overlay:
+
+.. zephyr-app-commands::
+ :zephyr-app: samples/subsys/settings
+ :board: qemu_x86
+ :goals: run
+ :conf: overlay-provisioning.conf
+ :compact:
+
+2. Place the sample soc-nv-flash-image.hex file in the build directory:
+
+ .. code-block:: shell
+
+ cp samples/subsys/settings/soc-nv-flash-image.hex build/zephyr
+
+3. Start the QEMU emulator with the following command:
+
+.. zephyr-app-commands::
+ :zephyr-app: samples/subsys/settings
+ :goals: run
+ :compact:
+
+To achieve the same with a real device, a separate flash image can be prepared
+that conforms to the selected memory backend and is flashed separately to the
+appropriate flash memory location.
+
+A tool to generate arbitrary NVS partition content is currently in preparation
+and will be contributed soon. In the meantime you can extract the flash content
+from a test device, store it to a binary file and convert it to a hex file using
+the ``objcpy`` tool:
+
+ .. code-block:: shell
+
+ objcopy -O ihex --change-section-address SOC_NV_FLASH=<your flash base address> \
+ <extracted-flash-mem-region>.bin build/zephyr/soc-nv-flash-image.hex
+
+And then flash the hex file to the device without erasing existing flash content.

samples/subsys/settings/overlay-provisioning.conf

@@ -0,0 +1,7 @@
+# See the sample's README for more information on how
+# to provision settings from a separate flash image.
+CONFIG_FLASH_SIMULATOR_PROVISION=y
+
+CONFIG_DEBUG=y
+CONFIG_DEBUG_OPTIMIZATIONS=y
+CONFIG_DEBUG_THREAD_INFO=y