cpu/esp32: fixes dependency problem for timer

Xtensa newlib version requires pthread_setcancelstate as symbol. Therefore, the module pthread was always used, which in turn requires the module xtimer. The xtimer module, however, uses TIMER_DEV(0). Therefore, tests/timers failed for TIMER_DEV(0).

cpu/esp32/Makefile.dep

@@ -52,6 +52,7 @@ endif
 
 # each device has SPI flash memory, but must be explicitly enabled
 ifneq (,$(filter esp_spiffs,$(USEMODULE)))
+    USEMODULE += esp_idf_spi_flash
     USEMODULE += spiffs
     USEMODULE += vfs
     export SPIFFS_STD_OPTION = -std=c99
@@ -70,6 +71,7 @@ endif
 
 ifneq (,$(filter shell,$(USEMODULE)))
     USEMODULE += newlib_syscalls_default
+    USEMODULE += ps
     USEMODULE += xtimer
 endif
 

cpu/esp32/Makefile.include

@@ -29,6 +29,10 @@ endif
 # SPECIAL module dependencies
 # cannot be done in Makefile.dep since Makefile.dep is included too late
 
+ifneq (,$(findstring core_thread_flags,$(USEMODULE)))
+    USEMODULE += pthread
+endif
+
 ifneq (,$(filter esp_gdbstub,$(USEMODULE)))
     USEMODULE += esp_gdb
 endif
@@ -57,18 +61,13 @@ export CPU ?= esp32
 export TARGET_ARCH ?= xtensa-esp32-elf
 export ESPTOOL ?= $(ESP32_SDK_DIR)/components/esptool_py/esptool/esptool.py
 
-USEMODULE += core_thread_flags
 USEMODULE += esp_idf
 USEMODULE += esp_idf_driver
 USEMODULE += esp_idf_esp32
 USEMODULE += esp_idf_soc
-USEMODULE += esp_idf_spi_flash
 USEMODULE += log
-USEMODULE += mtd
 USEMODULE += periph
 USEMODULE += periph_common
-USEMODULE += pthread
-USEMODULE += ps
 USEMODULE += random
 USEMODULE += xtensa
 
@@ -137,7 +136,7 @@ ifneq (,$(filter pthread,$(USEMODULE)))
     LINKFLAGS += $(BINDIR)/pthread.a
 endif
 
-LINKFLAGS += -lhal -lc -lg
+LINKFLAGS += -lhal -lg -lc -lg
 LINKFLAGS += -Wl,--end-group
 LINKFLAGS += -L$(RIOTCPU)/$(CPU)/ld/
 LINKFLAGS += -T$(RIOTCPU)/$(CPU)/ld/esp32.ld

cpu/esp32/periph/flash.c

@@ -18,6 +18,8 @@
  * @}
  */
 
+#if MODULE_MTD
+
 #define ENABLE_DEBUG (0)
 #include "debug.h"
 
@@ -429,3 +431,5 @@ static int _flash_power (mtd_dev_t *dev, enum mtd_power_state power)
 
     return -ENOTSUP;
 }
+
+#endif /* MODULE_MTD */

cpu/esp32/startup.c

@@ -316,9 +316,11 @@ static NORETURN void IRAM system_init (void)
                _sys_time.tm_year + 1900, _sys_time.tm_mon + 1, _sys_time.tm_mday,
                _sys_time.tm_hour, _sys_time.tm_min, _sys_time.tm_sec);
 
+    #if MODULE_MTD
     /* init flash drive */
     extern void spi_flash_drive_init (void);
     spi_flash_drive_init();
+    #endif
 
     /* initialize the board */
     board_init();

cpu/esp32/syscalls.c

@@ -113,6 +113,22 @@ int IRAM printf(const char* format, ...)
     return ret;
 }
 
+#ifndef MODULE_PTHREAD
+
+#define PTHREAD_CANCEL_DISABLE 1
+/*
+ * This is a dummy function to avoid undefined references when linking
+ * against newlib and module pthread is not used.
+ */
+int pthread_setcancelstate(int state, int *oldstate)
+{
+    if (oldstate) {
+        *oldstate = PTHREAD_CANCEL_DISABLE;
+    }
+    return 0;
+}
+#endif /*  MODULE_PTHREAD*/
+
 /**
  * @name Locking functions
  *