Merge pull request #13646 from benpicco/BACKUP_RAM

cpu: add BACKUP_RAM attribute

cpu/cortexm_common/include/cpu_conf_common.h

@@ -73,6 +73,20 @@ extern "C" {
  */
 #define PUF_SRAM_ATTRIBUTES __attribute__((used, section(".puf")))
 
+#if CPU_HAS_BACKUP_RAM || DOXYGEN
+/**
+ * @brief   Memory marked with this attribute is retained during deep sleep
+ *          and initialized with 0 on cold boot.
+ */
+#define BACKUP_RAM      __attribute__((section(".backup.bss")))
+
+/**
+ * @brief   Memory marked with this attribute is retained during deep sleep
+ *          and initialized with user provided data on cold boot.
+ */
+#define BACKUP_RAM_DATA __attribute__((section(".backup.data")))
+#endif /* CPU_HAS_BACKUP_RAM */
+
 #ifdef __cplusplus
 }
 #endif

cpu/esp32/include/cpu_conf.h

@@ -51,6 +51,18 @@ extern "C" {
  */
 #define PRINTF_BUFSIZ 256
 
+/**
+ * @brief   Memory marked with this attribute is retained during deep sleep
+ *          and initialized with 0 on cold boot.
+ */
+#define BACKUP_RAM      __attribute__((section(".rtc.bss")))
+
+/**
+ * @brief   Memory marked with this attribute is retained during deep sleep
+ *          and initialized with user provided data on cold boot.
+ */
+#define BACKUP_RAM_DATA __attribute__((section(".rtc.data")))
+
 #ifdef __cplusplus
 }
 #endif /* CPU_CONF_H */

cpu/lpc2387/include/cpu_conf.h

@@ -6,7 +6,6 @@
  * directory for more details.
  */
 
-
 #ifndef CPU_CONF_H
 #define CPU_CONF_H
 
@@ -127,6 +126,18 @@ extern "C" {
  */
 #define NUM_HEAPS (4)
 
+/**
+ * @brief   Memory marked with this attribute is retained during deep sleep
+ *          and initialized with 0 on cold boot.
+ */
+#define BACKUP_RAM      __attribute__((section(".backup.bss")))
+
+/**
+ * @brief   Memory marked with this attribute is retained during deep sleep
+ *          and initialized with user provided data on cold boot.
+ */
+#define BACKUP_RAM_DATA __attribute__((section(".backup.data")))
+
 #ifdef __cplusplus
 }
 #endif

tests/periph_backup_ram/main.c

@@ -39,7 +39,7 @@ int main(void)
      * counter anyway after wakeup, we did not sleep properly.
      */
     static int counter_noinit __attribute__((section(".noinit")));
-    static int counter __attribute__((section(".backup.bss")));
+    static int counter BACKUP_RAM;
 
     if (counter == 0) {
         puts("\nBackup RAM test\n");