Improvements to heap-memory and PSRAM handling (#4791)

* Improved heap and PSRAM handling

- Segment `allocateData()` uses more elaborate DRAM checking to reduce fragmentation and allow for larger setups to run on low heap
- Segment data allocation fails if minimum contiguous block size runs low to keep the UI working
- Increased `MAX_SEGMENT_DATA` to account for better segment data handling
- Memory allocation functions try to keep enough DRAM for segment data
- Added constant `PSRAM_THRESHOLD` to improve PSARM usage
- Increase MIN_HEAP_SIZE to reduce risk of breaking UI due to low memory for JSON response
- ESP32 makes use of IRAM (no 8bit access) for pixeluffers, freeing up to 50kB of RAM
- Fix to properly get available heap on all platforms: added function `getFreeHeapSize()`
- Bugfix for effects that divide by SEGLEN: don't run FX in service() if segment is not active
-Syntax fix in AR: calloc() uses (numelements, size) as arguments

* Added new functions for allocation and heap checking

- added `allocate_buffer()` function that can be used to allocate large buffers: takes parameters to set preferred ram location, including 32bit accessible RAM on ESP32. Returns null if heap runs low or switches to PSRAM
- getFreeHeapSize() and getContiguousFreeHeap() helper functions for all platforms to correctly report free useable heap
- updated some constants
- updated segment data allocation to free the data if it is large

- replaced "psramsafe" variable with it's #ifdef: BOARD_HAS_PSRAM and made accomodating changes
- added some compile-time checks to handle invalid env. definitions
- updated all allocation functions and some of the logic behind them
- added use of fast RTC-Memory where available
- increased MIN_HEAP_SIZE for all systems (improved stability in tests)
- updated memory calculation in web-UI to account for required segment buffer
- added UI alerts if buffer allocation fails
- made getUsedSegmentData() non-private (used in buffer alloc function)
- changed MAX_SEGMENT_DATA
- added more detailed memory log to DEBUG output
- added debug output to buffer alloc function

wled00/wled.h

@@ -167,16 +167,13 @@
 // The following is a construct to enable code to compile without it.
 // There is a code that will still not use PSRAM though:
 //    AsyncJsonResponse is a derived class that implements DynamicJsonDocument (AsyncJson-v6.h)
-#if defined(ARDUINO_ARCH_ESP32)
-extern bool psramSafe;
+#if defined(BOARD_HAS_PSRAM)
 struct PSRAM_Allocator {
   void* allocate(size_t size) {
-    if (psramSafe && psramFound()) return ps_malloc(size); // use PSRAM if it exists
-    else                           return malloc(size);    // fallback
+    return ps_malloc(size); // use PSRAM
   }
   void* reallocate(void* ptr, size_t new_size) {
-    if (psramSafe && psramFound()) return ps_realloc(ptr, new_size); // use PSRAM if it exists
-    else                           return realloc(ptr, new_size);    // fallback
+    return ps_realloc(ptr, new_size); // use PSRAM
   }
   void deallocate(void* pointer) {
     free(pointer);
@@ -894,8 +891,6 @@ WLED_GLOBAL byte optionType;
 WLED_GLOBAL bool configNeedsWrite  _INIT(false);        // flag to initiate saving of config
 WLED_GLOBAL bool doReboot          _INIT(false);        // flag to initiate reboot from async handlers
 
-WLED_GLOBAL bool psramSafe         _INIT(true);         // is it safe to use PSRAM (on ESP32 rev.1; compiler fix used "-mfix-esp32-psram-cache-issue")
-
 // status led
 #if defined(STATUSLED)
 WLED_GLOBAL unsigned long ledStatusLastMillis _INIT(0);
@@ -969,8 +964,11 @@ WLED_GLOBAL int8_t spi_sclk  _INIT(SPISCLKPIN);
 
 // global ArduinoJson buffer
 #if defined(ARDUINO_ARCH_ESP32)
-WLED_GLOBAL JsonDocument *pDoc _INIT(nullptr);
 WLED_GLOBAL SemaphoreHandle_t jsonBufferLockMutex _INIT(xSemaphoreCreateRecursiveMutex());
+#endif
+#ifdef BOARD_HAS_PSRAM
+// if board has PSRAM, use it for JSON document (allocated in setup())
+WLED_GLOBAL JsonDocument *pDoc _INIT(nullptr);
 #else
 WLED_GLOBAL StaticJsonDocument<JSON_BUFFER_SIZE> gDoc;
 WLED_GLOBAL JsonDocument *pDoc _INIT(&gDoc);