Heap init code improvements and updates (#8458)

* Heap init code improvements and updates

Moved secondary heap init code to flash.
  External -24 IRAM, +32 IROM
  IRAM     -76 IRAM, +64 IROM

General updates to umm_init call path and DEFINES to better align with
upstream. Name changes: UMM_INIT_HEAP with UMM_CHECK_INITIALIZED,
umm_init_stage_2 with _umm_init_heap, and umm_init_common with umm_init_heap.

Add file umm_cfgport.h to hold port-specific values. Stay focused
on heap initialization only move-related defines.

Improved comments.

Created a wrapper function for running pre-SDK code from flash.
Updated hwdt_app_entry to use it.

Update umm_init with option to run from ICACHE.
Added build define UMM_INIT_USE_ICACHE to move umm_init call path to flash.
When used frees up 160 bytes of IRAM at a cost of 208 bytes of IROM

Defaults to no change, umm_init call path will be in IRAM.

* Changed default to use IROM for umm_init() and option to revert back to UMM_INIT_USE_IRAM.

cores/esp8266/core_esp8266_app_entry_noextra4k.cpp

@@ -39,7 +39,19 @@ extern "C" void app_entry_redefinable(void)
 {
     g_pcont = &g_cont;
 
+    #ifdef UMM_INIT_USE_IRAM
+    /*
+     * Legacy option: the umm_init() call path must reside in IRAM.
+     */
     umm_init();
+    #else
+    /*
+     * Instruction cache is enabled/disabled around running umm_init().
+     * Allows the use of IROM (flash) to store umm_init().
+     */
+    mmu_wrap_irom_fn(umm_init);
+    #endif
+
     /* Call the entry point of the SDK code. */
     call_user_start();
 }

cores/esp8266/core_esp8266_main.cpp

@@ -365,7 +365,12 @@ extern "C" void app_entry_redefinable(void)
 
     /* Doing umm_init just once before starting the SDK, allowed us to remove
        test and init calls at each malloc API entry point, saving IRAM. */
+#ifdef UMM_INIT_USE_IRAM
     umm_init();
+#else
+    // umm_init() is in IROM
+    mmu_wrap_irom_fn(umm_init);
+#endif
     /* Call the entry point of the SDK code. */
     call_user_start();
 }

cores/esp8266/hwdt_app_entry.cpp

@@ -275,6 +275,7 @@
 #include <esp8266_peri.h>
 #include <uart.h>
 #include <pgmspace.h>
+#include "mmu_iram.h"
 
 extern "C" {
 #include <user_interface.h>
@@ -1007,6 +1008,18 @@ STATIC void IRAM_MAYBE handle_hwdt(void) {
 #endif
 }
 
+#if defined(DEBUG_ESP_HWDT_DEV_DEBUG) && !defined(USE_IRAM)
+static void printSanityCheck() {
+  ETS_PRINTF("\n\nsys_stack_first:         %p\n", sys_stack_first);
+  ETS_PRINTF(    "CONT_STACK:              %p\n", CONT_STACK);
+  ETS_PRINTF(    "g_pcont:                 %p\n", g_pcont);
+  ETS_PRINTF(    "ROM_STACK:               %p\n", ROM_STACK);
+  ETS_PRINTF(    "get_noextra4k_g_pcont(): %p\n", get_noextra4k_g_pcont());
+  ETS_PRINTF(    "g_rom_stack:             %p\n", g_rom_stack);
+  ETS_PRINTF(    "g_rom_stack_A16_sz:      0x%08X\n\n", g_rom_stack_A16_sz);
+}
+#endif //DEBUG_ESP_HWDT_DEV_DEBUG
+
 /*
  * Using Cache_Read_Enable/Cache_Read_Disable to reduce IRAM usage. Moved
  * strings and most functions to flash. At this phase of the startup, "C++" has
@@ -1019,34 +1032,11 @@ STATIC void IRAM_MAYBE handle_hwdt(void) {
  * https://richard.burtons.org/2015/06/12/esp8266-cache_read_enable/.
  * Additional insight can be gleemed from reviewing the ESP8266_RTOS_SDK.
  * (eg. ../components/bootloader_support/src/bootloader_utility.c)
+ *
+ * The logic to use Cache_Read_Enable and Cache_Read_Disable has been
+ * generalized into a wrapper function, mmu_wrap_irom_fn, and moved to
+ * mmu_iram.cpp.
  */
-#define ICACHE_SIZE_32 1
-#define ICACHE_SIZE_16 0
-
-extern "C" void Cache_Read_Disable(void);
-extern "C" void Cache_Read_Enable(uint8_t map, uint8_t p, uint8_t v);
-
-#ifndef USE_IRAM
-static void IRAM_ATTR __attribute__((noinline)) handle_hwdt_icache() __attribute__((used));
-void handle_hwdt_icache() {
-  Cache_Read_Enable(0, 0, ICACHE_SIZE_16);
-  handle_hwdt();
-  Cache_Read_Disable();
-}
-#endif // USE_IRAM
-
-
-#if defined(DEBUG_ESP_HWDT_DEV_DEBUG) && !defined(USE_IRAM)
-static void printSanityCheck() {
-  ETS_PRINTF("\n\nsys_stack_first:         %p\n", sys_stack_first);
-  ETS_PRINTF(    "CONT_STACK:              %p\n", CONT_STACK);
-  ETS_PRINTF(    "g_pcont:                 %p\n", g_pcont);
-  ETS_PRINTF(    "ROM_STACK:               %p\n", ROM_STACK);
-  ETS_PRINTF(    "get_noextra4k_g_pcont(): %p\n", get_noextra4k_g_pcont());
-  ETS_PRINTF(    "g_rom_stack:             %p\n", g_rom_stack);
-  ETS_PRINTF(    "g_rom_stack_A16_sz:      0x%08X\n\n", g_rom_stack_A16_sz);
-}
-#endif //DEBUG_ESP_HWDT_DEV_DEBUG
 
 /*
    hwdt_pre_sdk_init() is the result of a hook for development diagnotics which
@@ -1071,9 +1061,8 @@ void hwdt_pre_sdk_init(void) {
 #endif
 }
 
-static void IRAM_ATTR __attribute__((noinline)) hwdt_pre_sdk_init_icache(void) __attribute__((used));
+static void __attribute__((noinline)) hwdt_pre_sdk_init_icache(void) __attribute__((used));
 void hwdt_pre_sdk_init_icache(void) {
-  Cache_Read_Enable(0, 0, ICACHE_SIZE_16);
 #ifdef DEBUG_ESP_HWDT_UART_SPEED
   const uint32_t uart_divisor = set_uart_speed(0, DEBUG_ESP_HWDT_UART_SPEED);
 #endif
@@ -1085,7 +1074,6 @@ void hwdt_pre_sdk_init_icache(void) {
       adjust_uart_speed(uart_divisor);
   }
 #endif
-  Cache_Read_Disable();
 }
 
 /*
@@ -1106,6 +1094,7 @@ asm  (
     ".literal .umm_init, umm_init\n\t"
     ".literal .call_user_start, call_user_start\n\t"
     ".literal .get_noextra4k_g_pcont, get_noextra4k_g_pcont\n\t"
+    ".literal .mmu_wrap_irom_fn, mmu_wrap_irom_fn\n\t"
     ".align  4\n\t"
     ".global app_entry_redefinable\n\t"
     ".type   app_entry_redefinable, @function\n\t"
@@ -1129,7 +1118,9 @@ asm  (
 #ifdef USE_IRAM
     "call0   handle_hwdt\n\t"
 #else
-    "call0   handle_hwdt_icache\n\t"
+    "l32r    a0, .mmu_wrap_irom_fn\n\t"
+    "movi    a2, handle_hwdt\n\t"
+    "callx0  a0\n\t"
 #endif
     /*
      *  Use new calculated SYS stack from top.
@@ -1160,7 +1151,9 @@ asm  (
     /*
      * Allow for running additional diagnotics supplied at link time.
      */
-    "call0    hwdt_pre_sdk_init_icache\n\t"
+    "l32r     a0, .mmu_wrap_irom_fn\n\t"
+    "movi     a2, hwdt_pre_sdk_init_icache\n\t"
+    "callx0   a0\n\t"
 
     // In case somebody cares, leave things as we found them
     // - Restore ROM BSS zeros.
@@ -1174,7 +1167,12 @@ asm  (
      * improvements could possibly use hwdt_pre_sdk_init() to run other early
      * diagnostic tools.
      */
+#ifdef UMM_INIT_USE_IRAM
     "l32r     a0, .umm_init\n\t"
+#else
+    "l32r     a0, .mmu_wrap_irom_fn\n\t"
+    "l32r     a2, .umm_init\n\t"
+#endif
     "callx0   a0\n\t"
 
     "l32r     a3, .call_user_start\n\t"

cores/esp8266/mmu_iram.cpp

@@ -19,13 +19,16 @@
 #include "mmu_iram.h"
 #include <user_interface.h>
 
+#define ICACHE_SIZE_32 1
+#define ICACHE_SIZE_16 0
+
 extern "C" {
 
 #if (MMU_ICACHE_SIZE == 0x4000)
-#define SOC_CACHE_SIZE 0 // 16KB
+#define SOC_CACHE_SIZE ICACHE_SIZE_16
 #pragma message("ICACHE size 16K")
 #else
-#define SOC_CACHE_SIZE 1 // 32KB
+#define SOC_CACHE_SIZE ICACHE_SIZE_32
 #endif
 
 #if (MMU_ICACHE_SIZE == 0x4000)
@@ -185,8 +188,21 @@ extern "C" void pinMode( uint8_t pin, uint8_t mode ) {
 
     __pinMode( pin, mode );
 }
+#else   // #ifdef DEV_DEBUG_PRINT
+extern void Cache_Read_Disable(void);
 #endif  // #ifdef DEV_DEBUG_PRINT
 
+#else   // #if (MMU_ICACHE_SIZE == 0x4000)
+extern void Cache_Read_Enable(uint8_t map, uint8_t p, uint8_t v);
 #endif  // #if (MMU_ICACHE_SIZE == 0x4000)
 
+/*
+ * This wrapper is for running code from IROM (flash) before the SDK starts.
+ */
+void IRAM_ATTR mmu_wrap_irom_fn(void (*fn)(void)) {
+  Cache_Read_Enable(0, 0, ICACHE_SIZE_16);
+  fn();
+  Cache_Read_Disable();
+}
+
 };

cores/esp8266/mmu_iram.h

@@ -80,6 +80,24 @@ DBG_MMU_FLUSH(0)
 #define DBG_MMU_PRINTF(...) do {} while(false)
 #endif    // defined(DEV_DEBUG_PRINT) || defined(DEBUG_ESP_MMU)
 
+/*
+ * This wrapper is for running code from IROM (flash) before the SDK starts.
+ *
+ * Wraps a `void fn(void)` call with calls to enable and disable iCACHE.
+ * Allows a function that resides in IROM to run before the SDK starts.
+ *
+ * Do not use once the SDK has started.
+ *
+ * Because the SDK initialization code has not run, nearly all the SDK functions
+ * are not safe to call.
+ *
+ * Note printing at this early stage is complicated. To gain more insight,
+ * review DEV_DEBUG_PRINT build path in mmu_iram.cpp. To handle strings stored
+ * in IROM, review printing method and comments in hwdt_app_entry.cpp.
+ *
+ */
+void IRAM_ATTR mmu_wrap_irom_fn(void (*fn)(void));
+
 static inline __attribute__((always_inline))
 bool mmu_is_iram(const void *addr) {
   const uintptr_t iram_start = (uintptr_t)XCHAL_INSTRAM1_VADDR;

cores/esp8266/umm_malloc/umm_info.c

@@ -28,7 +28,7 @@
 void *umm_info(void *ptr, bool force) {
     UMM_CRITICAL_DECL(id_info);
 
-    UMM_INIT_HEAP;
+    UMM_CHECK_INITIALIZED();
 
     uint16_t blockNo = 0;
 

cores/esp8266/umm_malloc/umm_integrity.c

@@ -33,7 +33,7 @@ bool umm_integrity_check(void) {
     uint16_t prev;
     uint16_t cur;
 
-    UMM_INIT_HEAP;
+    UMM_CHECK_INITIALIZED();
 
     /* Iterate through all free blocks */
     prev = 0;

cores/esp8266/umm_malloc/umm_local.c

@@ -166,7 +166,7 @@ size_t umm_block_size(void) {
 #if defined(UMM_STATS) || defined(UMM_STATS_FULL)
 // Keep complete call path in IRAM
 size_t umm_free_heap_size_lw(void) {
-    UMM_INIT_HEAP;
+    UMM_CHECK_INITIALIZED();
 
     umm_heap_context_t *_context = umm_get_current_heap();
     return (size_t)_context->UMM_FREE_BLOCKS * sizeof(umm_block);