fix(rtc): fix .rtc_timer_data_in_rtc_mem wrongly in flash issue

components/esp_system/ld/esp32p4/memory.ld.in

@@ -83,10 +83,19 @@ MEMORY
    */
 #if CONFIG_ULP_COPROC_ENABLED
   lp_ram_seg(RW)  :                 org = 0x50108000 + CONFIG_ULP_COPROC_RESERVE_MEM,
-                                    len = 0x8000 - CONFIG_ULP_COPROC_RESERVE_MEM
+                                    len = 0x8000 - CONFIG_ULP_COPROC_RESERVE_MEM - RESERVE_RTC_MEM
 #else
-  lp_ram_seg(RW)  :                 org = 0x50108000 , len = 0x8000
+  lp_ram_seg(RW)  :                 org = 0x50108000 , len = 0x8000 - RESERVE_RTC_MEM
 #endif // CONFIG_ULP_COPROC_ENABLED
+
+  /* We reduced the size of lp_ram_seg by RESERVE_RTC_MEM value.
+     It reserves the amount of LP memory that we use for this memory segment.
+     This segment is intended for keeping:
+       - (lower addr) rtc timer data (s_rtc_timer_retain_mem, see esp_clk.c files).
+       - (higher addr) bootloader rtc data (s_bootloader_retain_mem, when a Kconfig option is on).
+     The aim of this is to keep data that will not be moved around and have a fixed address.
+  */
+  lp_reserved_seg(RW) :        org = 0x50000000 + 0x8000 - RESERVE_RTC_MEM, len = RESERVE_RTC_MEM
 }
 
 /* Heap ends at top of dram0_0_seg */
@@ -103,6 +112,7 @@ REGION_ALIAS("rtc_iram_seg", lp_ram_seg );
 REGION_ALIAS("rtc_data_seg", rtc_iram_seg );
 REGION_ALIAS("rtc_slow_seg", rtc_iram_seg );
 REGION_ALIAS("rtc_data_location", rtc_iram_seg );
+REGION_ALIAS("rtc_reserved_seg", lp_reserved_seg );
 
 #if CONFIG_APP_BUILD_USE_FLASH_SECTIONS
   REGION_ALIAS("default_code_seg", irom_seg);

components/esp_system/ld/esp32p4/sections.ld.in

@@ -104,6 +104,27 @@ SECTIONS
     _rtc_force_slow_end = ABSOLUTE(.);
   } > lp_ram_seg
 
+  /**
+   * This section holds RTC data that should have fixed addresses.
+   * The data are not initialized at power-up and are retained during deep sleep.
+   */
+  .rtc_reserved (NOLOAD):
+  {
+    . = ALIGN(4);
+    _rtc_reserved_start = ABSOLUTE(.);
+    /* New data can only be added here to ensure existing data are not moved.
+       Because data have adhered to the end of the segment and code is relied on it.
+       >> put new data here << */
+
+    *(.rtc_timer_data_in_rtc_mem .rtc_timer_data_in_rtc_mem.*)
+    KEEP(*(.bootloader_data_rtc_mem .bootloader_data_rtc_mem.*))
+    _rtc_reserved_end = ABSOLUTE(.);
+  } > rtc_reserved_seg
+
+  _rtc_reserved_length = _rtc_reserved_end - _rtc_reserved_start;
+  ASSERT((_rtc_reserved_length <= LENGTH(rtc_reserved_seg)),
+          "RTC reserved segment data does not fit.")
+
   /* Get size of rtc slow data based on rtc_data_location alias */
   _rtc_slow_length = (ORIGIN(rtc_slow_seg) == ORIGIN(rtc_data_location))
                         ? (_rtc_force_slow_end - _rtc_data_start)