cpu: Moved stdio_init() into cpu_init()

- Removed stdio_init() from newlib's _init(), as this is too late in the boot
  process to allow DEBUG()ing during periph_init()
- Added stdio_init() to the various cpu_init() routines of the ARM CPUs just
  before periph_init()

cpu/cc2538/cpu.c

@@ -21,6 +21,7 @@
 
 #include "cpu.h"
 #include "periph/init.h"
+#include "stdio_base.h"
 
 #define BIT(n)          ( 1UL << (n) )
 
@@ -48,6 +49,8 @@ void cpu_init(void)
     SYS_CTRL->I_MAP = 1;
     /* initialize the clock system */
     cpu_clock_init();
+    /* initialize stdio prior to periph_init() to allow use of DEBUG() there */
+    stdio_init();
     /* trigger static peripheral initialization */
     periph_init();
 }

cpu/cc26x0/cpu.c

@@ -20,6 +20,7 @@
 #include "cpu.h"
 #include "periph_conf.h"
 #include "periph/init.h"
+#include "stdio_base.h"
 
 #ifndef HF_CLOCK_SOURCE
 #define HF_CLOCK_SOURCE DDI_0_OSC_CTL0_SCLK_HF_SRC_SEL_RCOSC /* set 48MHz RCOSC */
@@ -44,6 +45,9 @@ void cpu_init(void)
     /* initialize the system clock */
     cpu_clock_init();
 
+    /* initialize stdio prior to periph_init() to allow use of DEBUG() there */
+    stdio_init();
+
     /* trigger static peripheral initialization */
     periph_init();
 }

cpu/efm32/cpu.c

@@ -22,6 +22,7 @@
 #include "cpu.h"
 #include "periph_conf.h"
 #include "periph/init.h"
+#include "stdio_base.h"
 
 #include "em_chip.h"
 #include "em_cmu.h"
@@ -172,6 +173,9 @@ void cpu_init(void)
     /* initialize power management interface */
     pm_init();
 
+    /* initialize stdio prior to periph_init() to allow use of DEBUG() there */
+    stdio_init();
+
     /* trigger static peripheral initialization */
     periph_init();
 }

cpu/ezr32wg/cpu.c

@@ -20,6 +20,7 @@
 #include "cpu.h"
 #include "periph_conf.h"
 #include "periph/init.h"
+#include "stdio_base.h"
 
 /**
  * @brief   Configure clock sources and the CPU frequency
@@ -60,6 +61,8 @@ void cpu_init(void)
     cortexm_init();
     /* Initialise clock sources and generic clocks */
     clk_init();
+    /* initialize stdio prior to periph_init() to allow use of DEBUG() there */
+    stdio_init();
     /* trigger static peripheral initialization */
     periph_init();
 }

cpu/kinetis/cpu.c

@@ -19,6 +19,7 @@
 
 #include "cpu.h"
 #include "periph/init.h"
+#include "stdio_base.h"
 #ifdef MODULE_PERIPH_MCG
 #include "mcg.h"
 #endif
@@ -41,6 +42,10 @@ void cpu_init(void)
     /* initialize the CPU clocking provided by the MCG module */
     kinetis_mcg_init();
 #endif
+
+    /* initialize stdio prior to periph_init() to allow use of DEBUG() there */
+    stdio_init();
+
     /* trigger static peripheral initialization */
     periph_init();
 }

cpu/lm4f120/cpu.c

@@ -24,6 +24,7 @@
 #include "irq.h"
 #include "periph/init.h"
 #include "periph_conf.h"
+#include "stdio_base.h"
 
 /**
  * @brief Initialize the CPU, set IRQ priorities
@@ -36,6 +37,9 @@ void cpu_init(void)
     /* initialize the clock system */
     cpu_clock_init(CLOCK_SOURCE);
 
+    /* initialize stdio prior to periph_init() to allow use of DEBUG() there */
+    stdio_init();
+
     /* trigger static peripheral initialization */
     periph_init();
 }

cpu/lpc1768/cpu.c

@@ -19,6 +19,7 @@
 
 #include "cpu.h"
 #include "periph/init.h"
+#include "stdio_base.h"
 
 /**
  * @brief Initialize the CPU, set IRQ priorities
@@ -27,6 +28,8 @@ void cpu_init(void)
 {
     /* initialize the Cortex-M core */
     cortexm_init();
+    /* initialize stdio prior to periph_init() to allow use of DEBUG() there */
+    stdio_init();
     /* trigger static peripheral initialization */
     periph_init();
 }

cpu/nrf51/cpu.c

@@ -21,6 +21,7 @@
 #include "nrf_clock.h"
 #include "periph_conf.h"
 #include "periph/init.h"
+#include "stdio_base.h"
 
 /**
  * @brief Initialize the CPU, set IRQ priorities
@@ -31,6 +32,8 @@ void cpu_init(void)
     cortexm_init();
     /* setup the HF clock */
     clock_init_hf();
+    /* initialize stdio prior to periph_init() to allow use of DEBUG() there */
+    stdio_init();
     /* trigger static peripheral initialization */
     periph_init();
 }

cpu/nrf52/cpu.c

@@ -26,6 +26,7 @@
 #include "nrf_clock.h"
 #include "periph_conf.h"
 #include "periph/init.h"
+#include "stdio_base.h"
 
 /* FTPAN helper functions */
 static bool ftpan_32(void);
@@ -83,6 +84,9 @@ void cpu_init(void)
     /* enable wake up on events for __WFE CPU sleep */
     SCB->SCR |= SCB_SCR_SEVONPEND_Msk;
 
+    /* initialize stdio prior to periph_init() to allow use of DEBUG() there */
+    stdio_init();
+
     /* trigger static peripheral initialization */
     periph_init();
 }

cpu/sam3/cpu.c

@@ -20,6 +20,7 @@
 #include "cpu.h"
 #include "periph_conf.h"
 #include "periph/init.h"
+#include "stdio_base.h"
 
 /**
  * @brief   Keys needed for editing certain PMC registers
@@ -90,6 +91,9 @@ void cpu_init(void)
     /* wait for master clock to be ready */
     while (!(PMC->PMC_SR & PMC_SR_MCKRDY));
 
+    /* initialize stdio prior to periph_init() to allow use of DEBUG() there */
+    stdio_init();
+
     /* trigger static peripheral initialization */
     periph_init();
 }

cpu/samd21/cpu.c

@@ -21,6 +21,7 @@
 #include "cpu.h"
 #include "periph_conf.h"
 #include "periph/init.h"
+#include "stdio_base.h"
 
 #ifndef CLOCK_8MHZ
 #define CLOCK_8MHZ          1
@@ -218,6 +219,8 @@ void cpu_init(void)
     cortexm_init();
     /* Initialise clock sources and generic clocks */
     clk_init();
+    /* initialize stdio prior to periph_init() to allow use of DEBUG() there */
+    stdio_init();
     /* trigger static peripheral initialization */
     periph_init();
 }

cpu/samd5x/cpu.c

@@ -20,6 +20,7 @@
 #include "cpu.h"
 #include "periph_conf.h"
 #include "periph/init.h"
+#include "stdio_base.h"
 
 static void xosc32k_init(void)
 {
@@ -137,6 +138,9 @@ void cpu_init(void)
     gclk_connect(6, GCLK_SOURCE_DFLL, 0);
 #endif
 
+    /* initialize stdio prior to periph_init() to allow use of DEBUG() there */
+    stdio_init();
+
     /* trigger static peripheral initialization */
     periph_init();
 }

cpu/saml1x/cpu.c

@@ -22,6 +22,7 @@
 #include "periph/init.h"
 #include "periph_conf.h"
 #include "board.h"
+#include "stdio_base.h"
 
 #ifdef CPU_FAM_SAML11
 #define _NVMCTRL NVMCTRL_SEC
@@ -115,6 +116,9 @@ void cpu_init(void)
     /* Setup GCLK generators */
     _gclk_setup(0, GCLK_GENCTRL_GENEN | GCLK_GENCTRL_SRC_OSC16M);
 
+    /* initialize stdio prior to periph_init() to allow use of DEBUG() there */
+    stdio_init();
+
     /* trigger static peripheral initialization */
     periph_init();
 }

cpu/saml21/cpu.c

@@ -21,6 +21,7 @@
 #include "cpu.h"
 #include "periph/init.h"
 #include "periph_conf.h"
+#include "stdio_base.h"
 
 static void _gclk_setup(int gclk, uint32_t reg)
 {
@@ -118,6 +119,9 @@ void cpu_init(void)
     SUPC->BOD33.bit.ENABLE=0;
 #endif
 
+    /* initialize stdio prior to periph_init() to allow use of DEBUG() there */
+    stdio_init();
+
     /* trigger static peripheral initialization */
     periph_init();
 }

cpu/stm32_common/cpu_init.c

@@ -33,6 +33,7 @@
  */
 
 #include "cpu.h"
+#include "stdio_base.h"
 #include "stmclk.h"
 #include "periph_cpu.h"
 #include "periph/init.h"
@@ -160,6 +161,8 @@ void cpu_init(void)
     /*  initialize DMA streams */
     dma_init();
 #endif
+    /* initialize stdio prior to periph_init() to allow use of DEBUG() there */
+    stdio_init();
     /* trigger static peripheral initialization */
     periph_init();
 }

sys/newlib_syscalls_default/syscalls.c

@@ -69,7 +69,7 @@ char *heap_top = &_sheap + 4;
  */
 void _init(void)
 {
-    stdio_init();
+    /* nothing to do here */
 }
 
 /**