libgpio, better initrd structure

Makefile

@@ -37,23 +37,27 @@ all:
 	@$(MAKE) -C src/kernel
 	@$(MAKE) -C src/fs
 	@$(MAKE) -C src/user
-	@echo "  INITRD"
-	@tools/rba initrd.img $$(find initrd/*)
-	@$(CROSS)$(OBJCOPY) -B arm -I binary -O elf32-littlearm initrd.img \
-		initrd.img.o
+	@$(MAKE) -C src/initrd
 	@echo "  LINK   " $(OUT)
 	@$(CROSS)$(CC) $(CFLAGS) $(LFLAGS) -o $(OUT) \
-		$$(find src/fs src/kernel src/user -name "*.o") initrd.img.o
+		$$(find src/fs src/kernel src/user src/initrd -name "*.o")
 
 crt:
 	@arm-stmos-$(CC) $(MCUFLAGS) -fsigned-char -Os -fPIE -c src/crt/crt0.c \
 		-o src/crt/crt0.o
 
+initrd:
+	@$(MAKE) -C src/initrd
+
+libgpio:
+	@$(MAKE) -C src/libgpio
+
 clean:
 	@echo "  CLEAN"
 	@$(MAKE) -C src/kernel clean
 	@$(MAKE) -C src/fs clean
 	@$(MAKE) -C src/user clean
+	@$(MAKE) -C src/initrd clean
 	@rm -f $(OUT)
 	@rm -f initrd.img initrd.img.o
 

initrd/Makefile

@@ -1,12 +0,0 @@
-##
-# A simple Makefile for building executables loadable by stmos.
-#
-
-ARCH = arm-stmos-
-CC = gcc -mcpu=cortex-m4 -mthumb -fsigned-char
-CFLAGS = -Os -fPIE
-
-all:
-	@$(ARCH)$(CC) $(CFLAGS) init.c -o init
-	@arm-stmos-strip init
-

src/initrd/Makefile

@@ -0,0 +1,25 @@
+##
+# A simple Makefile for building executables loadable by stmos.
+#
+
+CC = gcc -mcpu=cortex-m4 -mthumb -fsigned-char
+CFLAGS = -Os -fPIE -I../libgpio
+
+CFILES = $(wildcard *.c)
+OFILES = $(patsubst %.c, files/%, $(CFILES))
+
+all: $(OFILES)
+	@../../tools/rba initrd.img $$(find files/*)
+	@$(CROSS)$(OBJCOPY) -B arm -I binary -O elf32-littlearm initrd.img \
+		initrd.img.o
+
+files/%: %.c
+	@echo "  CC     " $<
+	@$(CROSS)$(CC) $(CFLAGS) $< ../libgpio/libgpio.a -o $@
+	@$(CROSS)strip $@
+
+clean:
+	@echo "  CLEAN"
+	@rm -f $(OFILES)
+	@rm -f initrd.img initrd.img.o
+

src/initrd/init.c

@@ -4,11 +4,21 @@
  */
 
 #include <stdio.h>
+#include <gpio.h>
+#include <syscalls.h>
 
 int main(void)
 {
+	gpioMode(5, OUTPUT);
+
 	printf("Hello, world!\n");
-	while (1);
+
+	while (1) {
+		gpioWrite(5, 1);
+		delay(1000);
+		gpioWrite(5, 0);
+		delay(500);
+	}
 	return 0;
 }
 

src/kernel/gpio.c

@@ -27,7 +27,7 @@ static GPIO_TypeDef *gpio_ports[8] = {
 
 void gpio_svc(uint32_t *args)
 {
-	GPIO_TypeDef *port = gpio_ports[args[1] / 16];
+	GPIO_TypeDef *port = gpio_ports[args[1] >> 4];
 	uint32_t pin = args[1] & 0xF;
 
 	switch (args[0]) {
@@ -46,6 +46,9 @@ void gpio_svc(uint32_t *args)
 	case 4:
 		gpio_dout(port, pin, args[2]);
 		break;
+	case 5:
+		*((int *)args[2]) = gpio_din(port, pin);
+		break;
 	}
 }
 

src/kernel/svc.c

@@ -59,6 +59,7 @@ void SVC_Handler(void) {
 		 * 2 - gpio_pupd
 		 * 3 - gpio_speed
 		 * 4 - gpio_dout
+		 * 5 - gpio_din
 		 */
 		gpio_svc(args);
 		break;

src/libgpio/Makefile

@@ -0,0 +1,38 @@
+##
+# @file Makefile
+# Script to build folder of source files
+#
+# Copyright (C) 2018 Clyne Sullivan
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+#
+
+CFILES = $(wildcard *.c)
+OFILES = $(patsubst %.c, %.o, $(CFILES))
+
+CFLAGS += -fPIC
+
+all: $(OFILES)
+	@$(CROSS)ar rcu libgpio.a $(OFILES)
+
+%.o: %.c
+	@echo "  CC     " $<
+	@$(CROSS)$(CC) $(CFLAGS) -c $< -o $@
+
+clean:
+	@echo "  CLEAN"
+	@rm -f $(OFILES)
+	@rm -f libgpio.a
+
+

src/libgpio/gpio.c

@@ -0,0 +1,78 @@
+#include "gpio.h"
+
+#include <stdint.h>
+
+void gpioMode(gpio_pin_t pin, int mode)
+{
+	register uint32_t r1 __asm("r1") = pin;
+	register uint32_t r2 __asm("r2") = mode;
+	__asm("\
+		mov r0, 0; \
+		mov r1, %0; \
+		mov r2, %1; \
+		svc 1; \
+	" :: "r" (r1), "r" (r2));
+}
+
+void gpioType(gpio_pin_t pin, int type)
+{
+	register uint32_t r1 __asm("r1") = pin;
+	register uint32_t r2 __asm("r2") = type;
+	__asm("\
+		mov r0, 1; \
+		mov r1, %0; \
+		mov r2, %1; \
+		svc 1; \
+	" :: "r" (r1), "r" (r2));
+}
+
+void gpioPuPd(gpio_pin_t pin, int pupd)
+{
+	register uint32_t r1 __asm("r1") = pin;
+	register uint32_t r2 __asm("r2") = pupd;
+	__asm("\
+		mov r0, 2; \
+		mov r1, %0; \
+		mov r2, %1; \
+		svc 1; \
+	" :: "r" (r1), "r" (r2));
+}
+
+void gpioSpeed(gpio_pin_t pin, int speed)
+{
+	register uint32_t r1 __asm("r1") = pin;
+	register uint32_t r2 __asm("r2") = speed;
+	__asm("\
+		mov r0, 3; \
+		mov r1, %0; \
+		mov r2, %1; \
+		svc 1; \
+	" :: "r" (r1), "r" (r2));
+}
+
+void gpioWrite(gpio_pin_t pin, int value)
+{
+	register uint32_t r1 __asm("r1") = pin;
+	register uint32_t r2 __asm("r2") = value;
+	__asm("\
+		mov r0, 4; \
+		mov r1, %0; \
+		mov r2, %1; \
+		svc 1; \
+	" :: "r" (r1), "r" (r2));
+}
+
+int gpioRead(gpio_pin_t pin)
+{
+	int ret = 0;
+	register uint32_t r1 __asm("r1") = pin;
+	register uint32_t r2 __asm("r2") = (uint32_t)&ret;
+	__asm("\
+		mov r0, 5; \
+		mov r1, %0; \
+		mov r2, %1; \
+		svc 1; \
+	" :: "r" (r1), "r" (r2));
+	return ret;
+}
+

src/libgpio/gpio.h

@@ -0,0 +1,57 @@
+#ifndef STMOS_GPIO_H_ 
+#define STMOS_GPIO_H_
+
+#define GP(a) ((a - 'A') << 4)
+
+/**
+ * Defines possible modes for a gpio pin.
+ */
+enum GPIO_MODE
+{
+	INPUT = 0, /**< digital input */
+	OUTPUT,    /**< digital output */
+	ALTERNATE, /**< alternate function */
+	ANALOG     /**< analog function */
+};
+
+/**
+ * Defines whether to use push-pull or open drain.
+ */
+enum GPIO_TYPE
+{
+	PUSHPULL = 0, /**< push-pull */
+	OPENDRAIN     /**< open drain */
+};
+
+/**
+ * Defines the pin's speed
+ */
+enum GPIO_SPEED
+{
+	LOW = 0, /**< low */
+	MEDIUM,  /**< medium */
+	HIGH,    /**< high */
+	VERYHIGH /**< very high/maximum */
+};
+
+/**
+ * Defines if a pullup or pulldown should be used.
+ */
+enum GPIO_PUPD
+{
+	NOPUPD,  /**< no pullup/pulldown */
+	PULLUP,  /**< use pullup */
+	PULLDOWN /**< use pulldown */
+};
+
+
+typedef unsigned int gpio_pin_t;
+
+void gpioMode(gpio_pin_t pin, int mode);
+void gpioType(gpio_pin_t pin, int type);
+void gpioPuPd(gpio_pin_t pin, int pupd);
+void gpioSpeed(gpio_pin_t pin, int speed);
+void gpioWrite(gpio_pin_t pin, int value);
+int gpioRead(gpio_pin_t pin);
+
+#endif // STMOS_GPIO_H_