Revive target: ESP8266

This patch updates ESP8266 build system and code base as well.
 - Removed unnecessary files.
 - Decreased code size.
 - Refactored jerry_{port, extapi, run}.c to make it more easy to handle.
 - Readme.md is updated as well which contains detailed step by step description about how to set up environment and use JerryScript.

Finally, it solves the related issue #1375.

JerryScript-DCO-1.0-Signed-off-by: Robert Fancsik frobert@inf.u-szeged.hu

targets/esp8266/Makefile.esp8266

@@ -12,17 +12,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-# use TAB-8
-
 CURDIR     = `pwd`
-ESP_SDK_PATH ?= $(SDK_PATH)
-ESP_INC    = $(ESP_SDK_PATH)/extra_include
-ESP_INC2   = $(ESP_SDK_PATH)/include
-ESP_LIB    = $(ESP_SDK_PATH)/lib
-TYPE       = release
-INTERM     = build/obj-esp8266
-OUTPUT     = build/bin/$(TYPE).esp8266
-SRCPATH    = targets/esp8266/source
+ESP_LIB    = $(SDK_PATH)/lib
+BUILD_DIR  = build/obj-esp8266
 COPYTARGET = targets/esp8266/libs
 USBDEVICE  ?= /dev/ttyUSB0
 JERRYHEAP  ?= 20
@@ -31,76 +23,50 @@ ESPTOOL    ?= /opt/Espressif/esptool-py/esptool.py
 # compile flags
 ESP_CFLAGS := -D__TARGET_ESP8266 -D__attr_always_inline___=
 
-MFORCE32 = `xtensa-lx106-elf-gcc --help=target | grep mforce-l32`
+MFORCE32 = $(shell xtensa-lx106-elf-gcc --help=target | grep mforce-l32)
 
 ifneq ($(MFORCE32),)
     # Your compiler supports the -mforce-l32 flag which means that
     # constants can be placed in ROM to free additional RAM
     ESP_CFLAGS += -DJERRY_CONST_DATA="__attribute__((aligned(4))) __attribute__((section(\".irom.text\")))"
+    ESP_CFLAGS += -mforce-l32
 endif
 
 ESP_CFLAGS += -Wl,-EL -fno-inline-functions
 ESP_CFLAGS += -ffunction-sections -fdata-sections
 ESP_CFLAGS += -mlongcalls -mtext-section-literals -mno-serialize-volatile
-ifneq ($(MFORCE32),)
-	ESP_CFLAGS += -mforce-l32
-endif
-
-# include path
-ESP_LIBS_INC :=$(CURDIR)/targets/esp8266/include
-ESP_LIBS_INC :=$(ESP_LIBS_INC);$(ESP_INC2)
-ESP_LIBS_INC :=$(ESP_LIBS_INC);$(ESP_INC2)/espressif
-ESP_LIBS_INC :=$(ESP_LIBS_INC);$(ESP_INC2)/freertos
-ESP_LIBS_INC :=$(ESP_LIBS_INC);$(ESP_INC2)/json
-ESP_LIBS_INC :=$(ESP_LIBS_INC);$(ESP_INC2)/lwip
-ESP_LIBS_INC :=$(ESP_LIBS_INC);$(ESP_INC2)/ssl
-
-# jerry related source files
-JERRY_BUILD_FILES := $(SRCPATH)/jerry_extapi.c
-JERRY_BUILD_FILES := $(JERRY_BUILD_FILES);$(SRCPATH)/jerry_run.c
-
 
 .PHONY: jerry js2c mkbin check-env flash clean
 
-
 all: check-env jerry js2c mkbin
 
-
 jerry:
-	mkdir -p $(INTERM)
-	mkdir -p $(OUTPUT)
+	mkdir -p $(BUILD_DIR)
 	mkdir -p $(COPYTARGET)
-	cmake -B$(INTERM) -H./ \
+	cmake -B$(BUILD_DIR) -H./ \
 	 -DENABLE_LTO=OFF \
-	 -DENABLE_VALGRIND=OFF \
-	 -DCMAKE_TOOLCHAIN_FILE=build/configs/toolchain_external.cmake \
+	 -DFEATURE_VALGRIND=OFF \
+	 -DCMAKE_TOOLCHAIN_FILE=cmake/toolchain_external.cmake \
 	 -DEXTERNAL_CMAKE_SYSTEM_PROCESSOR=xtensia-lx106 \
 	 -DEXTERNAL_CMAKE_C_COMPILER=xtensa-lx106-elf-gcc \
 	 -DEXTERNAL_CMAKE_C_COMPILER_ID=GNU \
-	 -DEXTERNAL_BUILD_ENTRY_FILE="$(JERRY_BUILD_FILES)" \
+	 -DJERRY_LIBC=OFF \
+	 -DJERRY_LIBM=ON \
+	 -DJERRY_CMDLINE=OFF \
+	 -DENABLE_ALL_IN_ONE=ON \
 	 -DEXTERNAL_COMPILE_FLAGS="$(ESP_CFLAGS)" \
-	 -DEXTERNAL_LIBC_INTERFACE="$(ESP_INC)" \
-	 -DEXTERNAL_LIBS_INTERFACE="$(ESP_LIBS_INC)" \
-	 -DEXTERNAL_MEM_HEAP_SIZE_KB=$(JERRYHEAP)
-
-	make -C $(INTERM) $(TYPE).external
-	cp `cat $(INTERM)/$(TYPE).external/list` $(OUTPUT)/.
-	cp $(OUTPUT)/lib$(TYPE).jerry-core.a $(COPYTARGET)/libjerrycore.a
-	cp $(OUTPUT)/lib$(TYPE).jerry-libm.lib.a $(COPYTARGET)/libjerrylibm.a
-	cp $(INTERM)/lib$(TYPE).external-entry.a $(OUTPUT)/.
-	cp $(OUTPUT)/lib$(TYPE).external-entry.a $(COPYTARGET)/libjerryentry.a
+	 -DMEM_HEAP_SIZE_KB=$(JERRYHEAP)
 
+	make -C$(BUILD_DIR) jerry-core jerry-libm
+	cp $(BUILD_DIR)/lib/libjerry-core.a $(COPYTARGET)/
+	cp $(BUILD_DIR)/lib/libjerry-libm.a $(COPYTARGET)/
 
 js2c:
-	cd targets/esp8266; ../../tools/js2c.py
-
+	tools/js2c.py --dest targets/esp8266/include --js-source targets/esp8266/js
 
 mkbin:
-	cd targets/esp8266; \
-	 make clean; \
-	 BOOT=new APP=1 SPI_SPEED=40 SPI_MODE=QIO SPI_SIZE_MAP=3 make; \
-	 BOOT=new APP=2 SPI_SPEED=40 SPI_MODE=QIO SPI_SIZE_MAP=3 make
-
+	make -Ctargets/esp8266 clean
+	make -Ctargets/esp8266 BOOT=new APP=0 SPI_SPEED=40 SPI_MODE=DIO SPI_SIZE_MAP=4
 
 check-env:
 ifndef SDK_PATH
@@ -110,16 +76,14 @@ ifndef BIN_PATH
 	$(error BIN_PATH is undefined for ESP8266)
 endif
 
-
 flash:
 	$(ESPTOOL) --port $(USBDEVICE) write_flash \
-	 0x00000 $(SDK_PATH)/bin/"boot_v1.4(b1).bin" \
-	 0x01000 $(BIN_PATH)/upgrade/user1.2048.new.3.bin \
-	 0x81000 $(BIN_PATH)/upgrade/user2.2048.new.3.bin \
-	 0x1FC000 $(SDK_PATH)/bin/esp_init_data_default.bin \
-	 0x1FE000 $(SDK_PATH)/bin/blank.bin
+	0x00000 $(BIN_PATH)/eagle.flash.bin \
+	0x20000 $(BIN_PATH)/eagle.irom0text.bin \
+	0x3FC000 $(SDK_PATH)/bin/esp_init_data_default.bin
 
+erase_flash:
+	$(ESPTOOL) --port $(USBDEVICE) erase_flash
 
 clean:
-	rm -rf $(INTERM)
-	rm -rf $(OUTPUT)
+	rm -rf $(BUILD_DIR)