system: add kconfig option for using parts of SRAM1 for IRAM

Using parts of SRAM1 for IRAM allows apps with more statically allocated IRAM

Closes https://github.com/espressif/esp-idf/issues/9824

components/esp_system/ld/esp32/memory.ld.in

@@ -48,6 +48,13 @@ ASSERT((CONFIG_ESP32_FIXED_STATIC_RAM_SIZE <= 0x2c200),
 #define DRAM0_0_SEG_LEN 0x2c200
 #endif
 
+#if CONFIG_ESP_SYSTEM_ESP32_SRAM1_REGION_AS_IRAM
+#define SRAM1_IRAM_LEN 0xA000
+#else
+#define SRAM1_IRAM_LEN 0x0
+#endif
+
+
 MEMORY
 {
   /* All these values assume the flash cache is on, and have the blocks this uses subtracted from the length
@@ -55,7 +62,7 @@ MEMORY
   are connected to the data port of the CPU and eg allow bytewise access. */
 
   /* IRAM for PRO cpu. Not sure if happy with this, this is MMU area... */
-  iram0_0_seg (RX) :                 org = 0x40080000, len = 0x20000
+  iram0_0_seg (RX) :                 org = 0x40080000, len = 0x20000 + SRAM1_IRAM_LEN
 
 #ifdef CONFIG_APP_BUILD_USE_FLASH_SECTIONS
   /* Even though the segment name is iram, it is actually mapped to flash
@@ -121,8 +128,14 @@ _heap_start = 0x3FFB0000 + DRAM0_0_SEG_LEN;
 _heap_start = _heap_low_start;
 #endif
 
-/* Heap ends at top of dram0_0_seg */
+_sram1_iram_start = 0x400A0000;
+_sram1_iram_len = ( _iram_end > _sram1_iram_start) ? (_iram_end - _sram1_iram_start) : 0;
+_heap_end = ALIGN(0x40000000 - _sram1_iram_len - 3, 4);
+
+#if CONFIG_ESP32_TRACEMEM_RESERVE_DRAM != 0
 _heap_end = 0x40000000 - CONFIG_ESP32_TRACEMEM_RESERVE_DRAM;
+#endif
+
 
 _data_seg_org = ORIGIN(rtc_data_seg);
 

components/esp_system/port/soc/esp32/Kconfig.memory

@@ -41,4 +41,19 @@ menu "Memory"
             This is possible due to handling of exceptions `LoadStoreError (3)` and `LoadStoreAlignmentError (9)`
             Each unaligned read/write access will incur a penalty of maximum of 167 CPU cycles.
 
+    menu "Non-backward compatible options"
+
+        config ESP_SYSTEM_ESP32_SRAM1_REGION_AS_IRAM
+            bool "Reserve parts of SRAM1 for app IRAM (WARNING, read help before enabling)"
+            depends on !ESP32_TRAX
+            help
+                Reserve parts of SRAM1 for app IRAM which was previously reserved for bootloader DRAM.
+                If booting an app on an older bootloader from before this option was introduced, the app may fail
+                to boot due to overlapping memory areas. If this is the case please test carefully before pushing out
+                any OTA updates.
+
+                The bootloader DRAM memory should be sufficient for any non-modified IDF bootloader.
+
+    endmenu
+
 endmenu # Memory