samples: nordic: system_off: use retained_mem on all targets

Using bare-metal approach for retention configuration
is no longer compatible with sys_poweroff() implementation.

Signed-off-by: Nikodem Kastelik <[email protected]>

samples/boards/nordic/system_off/CMakeLists.txt

@@ -5,6 +5,6 @@ find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
 project(nrf_system_off)
 
 target_sources(app PRIVATE src/main.c)
-if (CONFIG_APP_USE_NRF_RETENTION OR CONFIG_APP_USE_RETAINED_MEM)
+if (CONFIG_APP_USE_RETAINED_MEM)
   target_sources(app PRIVATE src/retained.c)
 endif()

samples/boards/nordic/system_off/Kconfig

@@ -3,23 +3,9 @@
 
 mainmenu "Nordic SYSTEM_OFF demo"
 
-choice
-	prompt "Use retention"
-	optional
-
-config APP_USE_NRF_RETENTION
-	bool "Use state retention in system off using nRF POWER"
-	depends on SOC_COMPATIBLE_NRF52X && CRC
-	help
-	  On some Nordic chips this application supports retaining
-	  memory while in system off using POWER peripheral.
-	  Select this to enable the feature.
-
 config APP_USE_RETAINED_MEM
 	bool "Use state retention in system off using retained_mem driver"
-	depends on RETAINED_MEM
-
-endchoice
+	select RETAINED_MEM
 
 config GRTC_WAKEUP_ENABLE
 	bool "Use GRTC to wake up device from system off"

samples/boards/nordic/system_off/README.rst

@@ -13,10 +13,10 @@ deep sleep on Nordic platforms.
 RAM Retention
 =============
 
-This sample can also can demonstrate RAM retention. By selecting
-``CONFIG_APP_USE_NRF_RETENTION=y`` or ``CONFIG_APP_USE_RETAINED_MEM=y``
-state related to number of boots, number of times system off was entered,
-and total uptime since initial power-on are retained in a checksummed data structure.
+This sample can also demonstrate RAM retention.
+By selecting ``CONFIG_APP_USE_RETAINED_MEM=y`` state related to number of boots,
+number of times system off was entered, and total uptime since initial power-on
+are retained in a checksummed data structure.
 RAM is configured to keep the containing section powered while in system-off mode.
 
 Requirements

samples/boards/nordic/system_off/boards/nrf52840dk_nrf52840.overlay

@@ -0,0 +1,22 @@
+/ {
+	sram0@2003f000 {
+		compatible = "zephyr,memory-region", "mmio-sram";
+		reg = <0x2003f000 DT_SIZE_K(4)>;
+		zephyr,memory-region = "RetainedMem";
+		status = "okay";
+
+		retainedmem0: retainedmem {
+			compatible = "zephyr,retained-ram";
+			status = "okay";
+		};
+	};
+
+	aliases {
+		retainedmemdevice = &retainedmem0;
+	};
+};
+
+&sram0 {
+	/* Shrink SRAM size to avoid overlap with retained memory region */
+	reg = <0x20000000 DT_SIZE_K(252)>;
+};

samples/boards/nordic/system_off/boards/nrf52dk_nrf52832.overlay

@@ -0,0 +1,22 @@
+/ {
+	sram0@20007000 {
+		compatible = "zephyr,memory-region", "mmio-sram";
+		reg = <0x20007000 DT_SIZE_K(4)>;
+		zephyr,memory-region = "RetainedMem";
+		status = "okay";
+
+		retainedmem0: retainedmem {
+			compatible = "zephyr,retained-ram";
+			status = "okay";
+		};
+	};
+
+	aliases {
+		retainedmemdevice = &retainedmem0;
+	};
+};
+
+&sram0 {
+	/* Shrink SRAM size to avoid overlap with retained memory region */
+	reg = <0x20000000 DT_SIZE_K(28)>;
+};

samples/boards/nordic/system_off/sample.yaml

@@ -22,32 +22,17 @@ tests:
         - "system off demo"
         - "Retained data not supported"
         - "Entering system off; press sw0 to restart"
-  sample.boards.nrf.system_off.nrf_retained:
+  sample.boards.nrf.system_off.retained_mem:
     integration_platforms:
       - nrf52840dk/nrf52840
     platform_allow:
       - nrf52840dk/nrf52840
       - nrf52dk/nrf52832
-    extra_configs:
-      - CONFIG_APP_USE_NRF_RETENTION=y
-    harness: console
-    harness_config:
-      type: multi_line
-      ordered: true
-      regex:
-        - "system off demo"
-        - "Retained data: INVALID"
-        - "Boot count: 1"
-        - "Off count: 0"
-        - "Active Ticks:"
-        - "Entering system off; press sw0 to restart"
-  sample.boards.nrf.system_off.retained_mem:
-    extra_args: DTC_OVERLAY_FILE="boards/nrf54l15dk_nrf54l15_cpuapp_retained_mem.overlay"
-    platform_allow:
       - nrf54l15dk/nrf54l15/cpuapp
+      - nrf54l15dk/nrf54l10/cpuapp
+      - nrf54l15dk/nrf54l05/cpuapp
     extra_configs:
       - CONFIG_APP_USE_RETAINED_MEM=y
-      - CONFIG_RETAINED_MEM=y
     harness: console
     harness_config:
       type: multi_line
@@ -62,6 +47,8 @@ tests:
   sample.boards.nrf.system_off.grtc_wakeup:
     platform_allow:
       - nrf54l15dk/nrf54l15/cpuapp
+      - nrf54l15dk/nrf54l10/cpuapp
+      - nrf54l15dk/nrf54l05/cpuapp
     extra_configs:
       - CONFIG_GRTC_WAKEUP_ENABLE=y
     harness: console
@@ -79,13 +66,13 @@ tests:
         - "Retained data not supported"
         - "Entering system off; wait 2 seconds to restart"
   sample.boards.nrf.system_off.retained_mem.grtc_wakeup:
-    extra_args: DTC_OVERLAY_FILE="boards/nrf54l15dk_nrf54l15_cpuapp_retained_mem.overlay"
     platform_allow:
       - nrf54l15dk/nrf54l15/cpuapp
+      - nrf54l15dk/nrf54l10/cpuapp
+      - nrf54l15dk/nrf54l05/cpuapp
     extra_configs:
       - CONFIG_APP_USE_RETAINED_MEM=y
       - CONFIG_GRTC_WAKEUP_ENABLE=y
-      - CONFIG_RETAINED_MEM=y
     harness: console
     harness_config:
       type: multi_line

samples/boards/nordic/system_off/src/main.c

@@ -35,7 +35,7 @@ int main(void)
 
 	printf("\n%s system off demo\n", CONFIG_BOARD);
 
-	if (IS_ENABLED(CONFIG_APP_USE_NRF_RETENTION) || IS_ENABLED(CONFIG_APP_USE_RETAINED_MEM)) {
+	if (IS_ENABLED(CONFIG_APP_USE_RETAINED_MEM)) {
 		bool retained_ok = retained_validate();
 
 		/* Increment for this boot attempt and update. */
@@ -81,7 +81,7 @@ int main(void)
 		return 0;
 	}
 
-	if (IS_ENABLED(CONFIG_APP_USE_NRF_RETENTION) || IS_ENABLED(CONFIG_APP_USE_RETAINED_MEM)) {
+	if (IS_ENABLED(CONFIG_APP_USE_RETAINED_MEM)) {
 		/* Update the retained state */
 		retained.off_count += 1;
 		retained_update();

samples/boards/nordic/system_off/src/retained.c

@@ -15,147 +15,24 @@
 #include <zephyr/sys/byteorder.h>
 #include <zephyr/sys/crc.h>
 
-#if CONFIG_APP_USE_NRF_RETENTION
-#include <hal/nrf_power.h>
-
-/* nRF52 RAM (really, RAM AHB slaves) are partitioned as:
- * * Up to 8 blocks of two 4 KiBy byte "small" sections
- * * A 9th block of with 32 KiBy "large" sections
- *
- * At time of writing the maximum number of large sections is 6, all
- * within the first large block.  Theoretically there could be more
- * sections in the 9th block, and possibly more blocks.
- */
-
-/* Inclusive address of RAM start */
-#define SRAM_BEGIN (uintptr_t)DT_REG_ADDR(DT_NODELABEL(sram0))
-
-/* Exclusive address of RAM end */
-#define SRAM_END (SRAM_BEGIN + (uintptr_t)DT_REG_SIZE(DT_NODELABEL(sram0)))
-
-/* Size of a controllable RAM section in the small blocks */
-#define SMALL_SECTION_SIZE 4096
-
-/* Number of controllable RAM sections in each of the lower blocks */
-#define SMALL_SECTIONS_PER_BLOCK 2
-
-/* Span of a small block */
-#define SMALL_BLOCK_SIZE (SMALL_SECTIONS_PER_BLOCK * SMALL_SECTION_SIZE)
-
-/* Number of small blocks */
-#define SMALL_BLOCK_COUNT 8
-
-/* Span of the SRAM area covered by small sections */
-#define SMALL_SECTION_SPAN (SMALL_BLOCK_COUNT * SMALL_BLOCK_SIZE)
-
-/* Inclusive address of the RAM range covered by large sections */
-#define LARGE_SECTION_BEGIN (SRAM_BEGIN + SMALL_SECTION_SPAN)
-
-/* Size of a controllable RAM section in large blocks */
-#define LARGE_SECTION_SIZE 32768
-
-#elif CONFIG_APP_USE_RETAINED_MEM
+#if DT_NODE_HAS_STATUS_OKAY(DT_ALIAS(retainedmemdevice))
 const static struct device *retained_mem_device = DEVICE_DT_GET(DT_ALIAS(retainedmemdevice));
-#endif
-
-/* Set or clear RAM retention in SYSTEM_OFF for the provided object.
- *
- * @param ptr pointer to the start of the retainable object
- *
- * @param len length of the retainable object
- *
- * @param enable true to enable retention, false to clear retention
- */
-static int ram_range_retain(const void *ptr,
-			    size_t len,
-			    bool enable)
-{
-	int rc = 0;
-
-#if CONFIG_APP_USE_NRF_RETENTION
-	/* This only works for nRF52 with the POWER module.
-	 * The other  Nordic chips use a different low-level API,
-	 * which is not currently used by this variant.
-	 */
-	uintptr_t addr = (uintptr_t)ptr;
-	uintptr_t addr_end = addr + len;
-
-	/* Error if the provided range is empty or doesn't lie
-	 * entirely within the SRAM address space.
-	 */
-	if ((len == 0U)
-	    || (addr < SRAM_BEGIN)
-	    || (addr > (SRAM_END - len))) {
-		return -EINVAL;
-	}
-
-	/* Iterate over each section covered by the range, setting the
-	 * corresponding RAM OFF retention bit in the parent block.
-	 */
-	do {
-		uintptr_t block_base = SRAM_BEGIN;
-		uint32_t section_size = SMALL_SECTION_SIZE;
-		uint32_t sections_per_block = SMALL_SECTIONS_PER_BLOCK;
-		bool is_large = (addr >= LARGE_SECTION_BEGIN);
-		uint8_t block = 0;
-
-		if (is_large) {
-			block = 8;
-			block_base = LARGE_SECTION_BEGIN;
-			section_size = LARGE_SECTION_SIZE;
-
-			/* RAM[x] supports only 16 sections, each its own bit
-			 * for POWER (0..15) and RETENTION (16..31).  We don't
-			 * know directly how many sections are present, so
-			 * assume they all are; the true limit will be
-			 * determined by the SRAM size.
-			 */
-			sections_per_block = 16;
-		}
-
-		uint32_t section = (addr - block_base) / section_size;
-
-		if (section >= sections_per_block) {
-			block += section / sections_per_block;
-			section %= sections_per_block;
-		}
-
-		uint32_t section_mask =
-			(POWER_RAM_POWERSET_S0RETENTION_On
-					 << (section + POWER_RAM_POWERSET_S0RETENTION_Pos));
-
-		if (enable) {
-			nrf_power_rampower_mask_on(NRF_POWER, block, section_mask);
-		} else {
-			nrf_power_rampower_mask_off(NRF_POWER, block, section_mask);
-		}
-
-		/* Move to the first address in the next section. */
-		addr += section_size - (addr % section_size);
-	} while (addr < addr_end);
-#elif CONFIG_APP_USE_RETAINED_MEM
-	/* Retention setting cannot be controlled runtime with retained_mem API */
-	(void)enable;
-	rc = retained_mem_write(retained_mem_device, 0, ptr, len);
 #else
-	#error "Unsupported retention setting"
+#error "retained_mem region not defined"
 #endif
 
-	return rc;
-}
-
-/* Retained data must be defined in a no-init section to prevent the C
- * runtime initialization from zeroing it before anybody can see it.
- * It is not necesarry when retained_mem driver is utilized
- * as in this case retained data is stored in an area not initialized in runtime.
- */
-__noinit struct retained_data retained;
+struct retained_data retained;
 
 #define RETAINED_CRC_OFFSET offsetof(struct retained_data, crc)
 #define RETAINED_CHECKED_SIZE (RETAINED_CRC_OFFSET + sizeof(retained.crc))
 
 bool retained_validate(void)
 {
+	int rc;
+
+	rc = retained_mem_read(retained_mem_device, 0, (uint8_t*)&retained, sizeof(retained));
+	__ASSERT_NO_MSG(rc == 0);
+
 	/* The residue of a CRC is what you get from the CRC over the
 	 * message catenated with its CRC.  This is the post-final-xor
 	 * residue for CRC-32 (CRC-32/ISO-HDLC) which Zephyr calls
@@ -174,19 +51,13 @@ bool retained_validate(void)
 	/* Reset to accrue runtime from this session. */
 	retained.uptime_latest = 0;
 
-	/* Reconfigure to retain the state during system off, regardless of
-	 * whether validation succeeded.  Although these values can sometimes
-	 * be observed to be preserved across System OFF, the product
-	 * specification states they are not retained in that situation, and
-	 * that can also be observed.
-	 */
-	(void)ram_range_retain(&retained, RETAINED_CHECKED_SIZE, true);
-
 	return valid;
 }
 
 void retained_update(void)
 {
+	int rc;
+
 	uint64_t now = k_uptime_ticks();
 
 	retained.uptime_sum += (now - retained.uptime_latest);
@@ -196,4 +67,7 @@ void retained_update(void)
 				  RETAINED_CRC_OFFSET);
 
 	retained.crc = sys_cpu_to_le32(crc);
+
+	rc = retained_mem_write(retained_mem_device, 0, (uint8_t*)&retained, sizeof(retained));
+	__ASSERT_NO_MSG(rc == 0);
 }