Reorganize to allow compiling and running AVR firmware

Makefile

@@ -1,5 +1,6 @@
 # Parameter for current board
-BOARD?=galp3-c
+#BOARD?=system76/galp3-c
+BOARD?=arduino/atmega2560
 
 # Set build directory
 BUILD=build/$(BOARD)

doc/README.md

@@ -0,0 +1,5 @@
+# System76 EC documetation
+
+## TODO
+
+- Define what functions are required in each board, ec, and arch

src/arch/8051/arch.mk

@@ -9,12 +9,12 @@ sim: $(BUILD)/ec.rom
 		--no-default-features \
 		-- $<
 
-# Convert from Intel Hex format to binary
+# Convert from Intel Hex file to binary file
 $(BUILD)/ec.rom: $(BUILD)/ec.ihx
 	@mkdir -p $(@D)
 	makebin -p < $< > $@
 
-# Link object files into Intel Hex format
+# Link object files into Intel Hex file
 $(BUILD)/ec.ihx: $(OBJ)
 	@mkdir -p $(@D)
 	$(CC) -o $@ $^

src/arch/avr/arch.mk

@@ -0,0 +1,26 @@
+CC=avr-gcc -mmcu=$(EC)
+OBJ=$(patsubst src/%.c,$(BUILD)/%.o,$(SRC))
+
+# Run EC rom in simulator
+sim: $(BUILD)/ec.elf
+	simavr $< --mcu $(EC)
+
+# Convert from Intel Hex file to binary file
+$(BUILD)/ec.rom: $(BUILD)/ec.ihx
+	@mkdir -p $(@D)
+	makebin -p < $< > $@
+
+# Convert from ELF file to Intel Hex file
+$(BUILD)/ec.ihx: $(OBJ)
+	@mkdir -p $(@D)
+	avr-objcopy -j .text -j .data -O ihex $< $@
+
+# Link object files into ELF file
+$(BUILD)/ec.elf: $(OBJ)
+	@mkdir -p $(@D)
+	$(CC) -o $@ $^
+
+# Compile C files into object files
+$(BUILD)/%.o: src/%.c $(INCLUDE)
+	@mkdir -p $(@D)
+	$(CC) -o $@ -c $<

src/board/arduino/atmega2560/board.mk

@@ -0,0 +1 @@
+EC=atmega2560

src/board/arduino/atmega2560/include/cpu.h

@@ -0,0 +1,6 @@
+#ifndef CPU_H
+#define CPU_H
+
+#define F_CPU 16000000ULL
+
+#endif // CPU_H

src/board/arduino/atmega2560/include/stdio.h

@@ -0,0 +1,7 @@
+#ifndef STDIO_H
+#define STDIO_H
+
+extern struct Uart * stdio_uart;
+void stdio_init(int num, unsigned long baud);
+
+#endif // STDIO_H

src/board/arduino/atmega2560/include/uart.h

@@ -0,0 +1,31 @@
+#ifndef UART_H
+#define UART_H
+
+#include <stdint.h>
+
+struct Uart {
+    volatile uint8_t * a;
+    volatile uint8_t * b;
+    volatile uint8_t * c;
+    volatile uint8_t * data;
+    volatile uint8_t * baud_l;
+    volatile uint8_t * baud_h;
+    uint8_t a_read;
+    uint8_t a_write;
+    uint8_t a_init;
+    uint8_t b_init;
+    uint8_t c_init;
+};
+
+void uart_init(struct Uart * uart, unsigned long baud);
+
+int uart_count();
+struct Uart * uart_new(int num);
+
+unsigned char uart_can_read(struct Uart * uart);
+unsigned char uart_can_write(struct Uart * uart);
+
+unsigned char uart_read(struct Uart * uart);
+void uart_write(struct Uart * uart, unsigned char data);
+
+#endif // UART_H

src/board/arduino/atmega2560/main.c

@@ -0,0 +1,14 @@
+#include <stdio.h>
+
+#include "include/stdio.h"
+
+void init(void) {
+    stdio_init(0, 9600);
+}
+
+void main(void) {
+    init();
+
+    printf("Hello from System76 EC for the Arduino Mega 2560!\n");
+    for (;;) {}
+}

src/board/arduino/atmega2560/stdio.c

@@ -0,0 +1,29 @@
+#include <stdio.h>
+
+#include "include/stdio.h"
+#include "include/uart.h"
+
+struct Uart * stdio_uart = NULL;
+
+int stdio_get(FILE * stream) {
+    return (int)uart_read(stdio_uart);
+}
+
+int stdio_put(char data, FILE * stream) {
+    if (data == '\n') {
+        uart_write(stdio_uart, '\r');
+    }
+    uart_write(stdio_uart, (unsigned char)data);
+    return 0;
+}
+
+FILE stdio_file = FDEV_SETUP_STREAM(stdio_put, stdio_get, _FDEV_SETUP_RW);
+
+void stdio_init(int num, unsigned long baud) {
+    struct Uart * uart = uart_new(num);
+    if(uart != NULL) {
+        uart_init(uart, baud);
+        stdio_uart = uart;
+        stdin = stdout = stderr = &stdio_file;
+    }
+}

src/board/arduino/atmega2560/uart.c

@@ -0,0 +1,74 @@
+#include <stdio.h>
+#include <avr/io.h>
+
+#include "include/cpu.h"
+#include "include/uart.h"
+
+#define UART(N) \
+    { \
+        &UCSR ## N ## A, \
+        &UCSR ## N ## B, \
+        &UCSR ## N ## C, \
+        &UDR ## N, \
+        &UBRR ## N ## L, \
+        &UBRR ## N ## H, \
+        _BV(RXC ## N), \
+        _BV(UDRE ## N), \
+        0, \
+        _BV(RXEN ## N) | _BV(TXEN ## N), \
+        _BV(UCSZ ## N ## 1) | _BV(UCSZ ## N ## 0) \
+    }
+
+#if defined(__AVR_ATmega32U4__)
+    static struct Uart UARTS[] = {
+        UART(1)
+    };
+#elif defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
+    static struct Uart UARTS[] = {
+        UART(0),
+        UART(1),
+        UART(2),
+        UART(3)
+    };
+#else
+    #error "Could not find UART definitions"
+#endif
+
+int uart_count() {
+    return sizeof(UARTS)/sizeof(struct Uart);
+}
+
+struct Uart * uart_new(int num) {
+    if (num < uart_count()) {
+        return &UARTS[num];
+    } else {
+        return NULL;
+    }
+}
+
+void uart_init(struct Uart * uart, unsigned long baud) {
+    unsigned long baud_prescale = (F_CPU / (baud * 16UL)) - 1;
+    *(uart->baud_h) = (uint8_t)(baud_prescale>>8);
+    *(uart->baud_l) = (uint8_t)(baud_prescale);
+    *(uart->a) = uart->a_init;
+    *(uart->b) = uart->b_init;
+    *(uart->c) = uart->c_init;
+}
+
+unsigned char uart_can_read(struct Uart * uart) {
+    return (*(uart->a)) & uart->a_read;
+}
+
+unsigned char uart_read(struct Uart * uart) {
+    while (!uart_can_read(uart)) ;
+    return *(uart->data);
+}
+
+unsigned char uart_can_write(struct Uart * uart) {
+    return (*(uart->a)) & uart->a_write;
+}
+
+void uart_write(struct Uart * uart, unsigned char data) {
+    while (!uart_can_write(uart)) ;
+    *(uart->data) = data;
+}

src/ec/atmega2560/ec.mk

@@ -0,0 +1 @@
+ARCH=avr