Rework support for >4MB modules: place SPIFFS after SDK data (#1646)

app/platform/flash_api.c

@@ -35,6 +35,12 @@ uint32_t flash_safe_get_size_byte(void)
     if (flash_size == 0)
     {
         flash_size = flash_detect_size_byte();
+#if !defined(FLASH_SAFE_API)
+	// clip maximum flash size to 4MByte if "SAFE API" is not used
+	if (flash_size > FLASH_SIZE_4MBYTE) {
+	    flash_size = FLASH_SIZE_4MBYTE;
+	}
+#endif
     }
     return flash_size;
 }

app/spiffs/spiffs.c

@@ -53,8 +53,14 @@ static bool myspiffs_set_location(spiffs_config *cfg, int align, int offset, int
 #ifdef SPIFFS_FIXED_LOCATION
   cfg->phys_addr = (SPIFFS_FIXED_LOCATION + block_size - 1) & ~(block_size-1);
 #else
+  if (flash_safe_get_size_byte() <= FLASH_SIZE_4MBYTE) {
+    // 256kByte - 4MByte modules: SPIFFS partition starts right after firmware image
     cfg->phys_addr = ( u32_t )platform_flash_get_first_free_block_address( NULL ) + offset;
     cfg->phys_addr = (cfg->phys_addr + align - 1) & ~(align - 1);
+  } else {
+    // > 4MByte modules: SPIFFS partition starts after SDK data
+    cfg->phys_addr = flash_rom_get_size_byte();
+  }
 #endif
 #ifdef SPIFFS_SIZE_1M_BOUNDARY
   cfg->phys_size = ((0x100000 - (SYS_PARAM_SEC_NUM * INTERNAL_FLASH_SECTOR_SIZE) - ( ( u32_t )cfg->phys_addr )) & ~(block_size - 1)) & 0xfffff;

app/user/user_main.c

@@ -122,8 +122,8 @@ void nodemcu_init(void)
         return;
     }
 
-#if defined(FLASH_SAFE_API)
+    if( flash_safe_get_size_byte() <= FLASH_SIZE_4MBYTE ) {
-    if( flash_safe_get_size_byte() != flash_rom_get_size_byte()) {
+        if( flash_safe_get_size_byte() != flash_rom_get_size_byte() ) {
             NODE_ERR("Self adjust flash size.\n");
             // Fit hardware real flash size.
             flash_rom_set_size_byte(flash_safe_get_size_byte());
@@ -132,7 +132,16 @@ void nodemcu_init(void)
             // Don't post the start_lua task, we're about to reboot...
             return;
         }
-#endif // defined(FLASH_SAFE_API)
+    } else if( (flash_rom_get_size_byte() < FLASH_SIZE_1MBYTE) ||
+               (flash_rom_get_size_byte() > FLASH_SIZE_4MBYTE) ) {
+        NODE_ERR("Locking flash size for SDK to 1MByte.\n");
+        // SDK/ROM can't handle flash size > 4MByte, ensure a minimum of 1MByte for firmware image
+        flash_rom_set_size_byte(FLASH_SIZE_1MBYTE);
+
+        system_restart ();
+        // Don't post the start_lua task, we're about to reboot...
+        return;
+    }
 
 #if defined ( CLIENT_SSL_ENABLE ) && defined ( SSL_BUFFER_SIZE )
     espconn_secure_set_size(ESPCONN_CLIENT, SSL_BUFFER_SIZE);

docs/en/flash.md

@@ -32,6 +32,8 @@ Run the following command to flash an *aggregated* binary as is produced for exa
 - esptool.py is under heavy development. It's advised you run the latest version (check with `esptool.py version`). Since this documentation may not have been able to keep up refer to the [esptool flash modes documentation](https://github.com/themadinventor/esptool#flash-modes) for current options and parameters.
 - In some uncommon cases, the [SDK init data](#sdk-init-data) may be invalid and NodeMCU may fail to boot. The easiest solution is to fully erase the chip before flashing:
 `esptool.py --port <serial-port-of-ESP8266> erase_flash`
+- Modules with flash chips larger than 4&nbsp;MByte (e.g. WeMos D1 mini pro) need to be manually configured to at least 1&nbsp;MByte: Firmware image and SDK init data occupy the first MByte, while the remaining 7/15&nbsp;MByte of the flash are used for SPIFFS:
+`esptool.py --port <serial-port-of-ESP8266> write_flash -fm <mode> -fs 8m 0x00000 <nodemcu-firmware>.bin`
 
 ### NodeMCU Flasher
 > A firmware Flash tool for NodeMCU...We are working on next version and will use QT framework. It will be cross platform and open-source.