cpu/atmega328p: add atmega328p mcu support

add atmega328p support with:
uart, timer, spi and gpio

cpu/atmega328p/Makefile

+# define the module that is build
+MODULE = cpu
+# add a list of subdirectories, that should also be build
+DIRS = $(ATMEGA_COMMON)
+
+include $(RIOTBASE)/Makefile.base

cpu/atmega328p/Makefile.include

+# this CPU implementation is using the new core/CPU interface
+export CFLAGS += -DCOREIF_NG=1
+
+# tell the build system that the CPU depends on the atmega common files
+USEMODULE += atmega_common
+
+# define path to atmega common module, which is needed for this CPU
+export ATMEGA_COMMON = $(RIOTCPU)/atmega_common/
+
+# CPU depends on the atmega common module, so include it
+include $(ATMEGA_COMMON)Makefile.include

cpu/atmega328p/cpu.c

+/*
+ * Copyright (C) 2014 Freie Universität Berlin, Hinnerk van Bruinehsen
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     cpu_atmega328p
+ * @{
+ *
+ * @file
+ * @brief       Implementation of the CPU initialization
+ *
+ * @author      Hinnerk van Bruinehsen <h.v.bruinehsen@fu-berlin.de>
+ * @}
+ */
+
+#include "cpu.h"
+
+/**
+ * @brief Initialize the CPU, set IRQ priorities
+ */
+void cpu_init(void)
+{
+    /* Right now we need to do nothing here */
+    ;
+}

cpu/atmega328p/doc.txt

+/**
+ * @defgroup        cpu_atmega328p Atmel ATmega328p
+ * @ingroup         cpu
+ * @brief           Implementation of Atmel's ATmega328p MCU
+ */
+
+/**
+ * @defgroup        cpu_atmega328p_definitions Atmel ATmega328p Definitions
+ * @ingroup         cpu_atmega328p
+ */

cpu/atmega328p/include/cpu_conf.h

+/*
+ * Copyright (C) 2014 Freie Universität Berlin, Hinnerk van Bruinehsen
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup         cpu_atmega328p
+ * @{
+ *
+ * @file
+ * @brief           Implementation specific CPU configuration options
+ *
+ * @author          Hauke Petersen <hauke.petersen@fu-berlin.de>
+ * @author          Hinnerk van Bruinehsen <h.v.bruinehsen@fu-berlin.de>
+ */
+
+#ifndef CPU_CONF_H
+#define CPU_CONF_H
+
+#include "atmega_regs_common.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @name Kernel configuration
+ *
+ * Since printf seems to get memory allocated by the linker/avr-libc the stack
+ * size tested sucessfully even with pretty small stacks.k
+ * @{
+ */
+#define THREAD_EXTRA_STACKSIZE_PRINTF    (128)
+
+#ifndef THREAD_STACKSIZE_DEFAULT
+#define THREAD_STACKSIZE_DEFAULT   (256)
+#endif
+
+#define THREAD_STACKSIZE_IDLE      (128)
+#define ISR_STACKSIZE              (0)
+/** @} */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* CPU_CONF_H */
+/** @} */

cpu/atmega328p/include/periph_cpu.h

+/*
+ * Copyright (C) 2015 HAW Hamburg
+ *               2016 Freie Universität Berlin
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup         cpu_atmega328p
+ * @{
+ *
+ * @file
+ * @brief           CPU specific definitions for internal peripheral handling
+ *
+ * @author          René Herthel <rene-herthel@outlook.de>
+ * @author          Hauke Petersen <hauke.petersen@fu-berlin.de>
+ */
+
+#ifndef PERIPH_CPU_H_
+#define PERIPH_CPU_H_
+
+#include "periph_cpu_common.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief   Define a CPU specific GPIO pin generator macro
+ */
+#define GPIO_PIN(x, y)          ((x << 4) | y)
+
+/**
+ * @brief   Available ports on the ATmega328p family
+ */
+enum {
+    PORT_B = 1,       /**< port B */
+    PORT_C = 2,       /**< port C */
+    PORT_D = 3       /**< port D */
+};
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* PERIPH_CPU_H_ */
+/** @} */

cpu/atmega328p/lpm_arch.c

+/*
+ * Copyright (C) 2014 Freie Universität Berlin, Hinnerk van Bruinehsen
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     cpu_atmega328p
+ * @{
+ *
+ * @file
+ * @brief       Implementation of the kernels power management interface
+ *
+ * @author      Hinnerk van Bruinehsen <h.v.bruinehsen@fu-berlin.de>
+ *
+ * @}
+ */
+
+#include "arch/lpm_arch.h"
+
+void lpm_arch_init(void)
+{
+    /* TODO */
+}
+
+enum lpm_mode lpm_arch_set(enum lpm_mode target)
+{
+    (void) target;
+    /* TODO */
+    return 0;
+}
+
+enum lpm_mode lpm_arch_get(void)
+{
+    /* TODO */
+    return 0;
+}
+
+void lpm_arch_awake(void)
+{
+    /* TODO */
+}
+
+void lpm_arch_begin_awake(void)
+{
+    /* TODO */
+}
+
+void lpm_arch_end_awake(void)
+{
+    /* TODO */
+}

cpu/atmega328p/reboot_arch.c

+/*
+ * Copyright (C) 2016 Kaspar Schleiser <kaspar@schleiser.de>
+ *               2014 Freie Universität Berlin, Hinnerk van Bruinehsen
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     cpu_atmega328p
+ * @{
+ *
+ * @file
+ * @brief       Implementation of the kernels reboot interface
+ *
+ * @author      Hinnerk van Bruinehsen <h.v.bruinehsen@fu-berlin.de>
+ * @author      Kaspar Schleiser <kaspar@schleiser.de>
+ *
+ * @}
+ */
+
+#include <avr/wdt.h>
+
+#include "cpu.h"
+
+void reboot(void)
+{
+    /*
+     * Since the AVR doesn't support a real software reset, we set the Watchdog
+     * Timer on a 250ms timeout. Consider this a kludge.
+     */
+    wdt_enable(WDTO_250MS);
+    while(1);
+}

cpu/atmega328p/startup.c

+/*
+ * Copyright (C) 2014 Freie Universität Berlin, Hinnerk van Bruinehsen
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     cpu_atmega328p
+ * @{
+ *
+ * @file
+ * @brief       Startup code and interrupt vector definition
+ *
+ * @author     Hinnerk van Bruinehsen <h.v.bruinehsen@fu-berlin.de>
+ *
+ * @}
+ */
+
+#include <stdint.h>
+#include <avr/interrupt.h>
+#include <avr/io.h>
+
+/* For Catchall-Loop */
+#include "board.h"
+
+
+/**
+ * @brief functions for initializing the board, std-lib and kernel
+ */
+extern void board_init(void);
+extern void kernel_init(void);
+extern void __libc_init_array(void);
+
+/**
+ * @brief This pair of functions hook circumvent the call to main
+ *
+ * avr-libc normally uses the .init9 section for a call to main. This call
+ * seems to be not replaceable without hacking inside the library. We
+ * circumvent the call to main by using section .init7 to call the function
+ * reset_handler which therefore is the real entry point and  section .init8
+ * which should never be reached but just in case jumps to exit.
+ * This way there should be no way to call main directly.
+ */
+void init7_ovr(void) __attribute__((naked)) __attribute__((section(".init7")));
+void init8_ovr(void) __attribute__((naked)) __attribute__((section(".init8")));
+
+
+void init7_ovr(void)
+{
+    __asm__("call reset_handler");
+}
+
+void init8_ovr(void)
+{
+    __asm__("jmp exit");
+}
+/**
+ * @brief This function is the entry point after a system reset
+ *
+ * After a system reset, the following steps are necessary and carried out:
+ * 1. initialize the board (sync clock, setup std-IO)
+ * 2. initialize and start RIOTs kernel
+ */
+void reset_handler(void)
+{
+    /* initialize the board and startup the kernel */
+    board_init();
+    /* startup the kernel */
+    kernel_init();
+}