1 files changed, 90 insertions, 0 deletions
diff --git a/src/kernel/gpio.c b/src/kernel/gpio.c
new file mode 100644
index 0000000..1c81d11
--- /dev/null
+++ b/src/kernel/gpio.c
@@ -0,0 +1,90 @@
+/**
+ * @file gpio.c
+ * Abstracts gpio access, makes things easier
+ *
+ * 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/>.
+ */
+
+#include "gpio.h"
+
+static const GPIO_TypeDef *gpio_ports[8] = {
+	GPIOA, GPIOB, GPIOC, GPIOD,
+	GPIOE, GPIOF, GPIOG, GPIOH
+};
+
+void gpio_svc(uint32_t *args)
+{
+	GPIO_TypeDef *port = gpio_ports[args[1] / 16];
+	uint32_t pin = args[1] & 0xF;
+
+	switch (args[0]) {
+	case 0:
+		gpio_mode(port, pin, args[2]);
+		break;
+	case 1:
+		gpio_type(port, pin, args[2]);
+		break;
+	case 2:
+		gpio_pupd(port, pin, args[2]);
+		break;
+	case 3:
+		gpio_speed(port, pin, args[2]);
+		break;
+	case 4:
+		gpio_dout(port, pin, args[2]);
+		break;
+	}
+}
+
+void gpio_init(void)
+{
+	// enable clocks
+	RCC->AHB2ENR |= 0x0F;
+}
+
+void gpio_pupd(GPIO_TypeDef *port, uint32_t pin, uint32_t pupd)
+{
+	port->PUPDR &= ~(0x03 << (2 * pin));
+	port->PUPDR |= pupd << (2 * pin);
+}
+
+void gpio_speed(GPIO_TypeDef *port, uint32_t pin, uint32_t speed)
+{
+	port->OSPEEDR &= ~(0x03 << (2 * pin));
+	port->OSPEEDR |= speed << (2 * pin);
+}
+
+void gpio_type(GPIO_TypeDef *port, uint32_t pin, uint32_t type)
+{
+	port->OTYPER &= ~(1 << pin);
+	port->OTYPER |= type << pin;
+}
+
+void gpio_mode(GPIO_TypeDef *port, uint32_t pin, uint32_t mode)
+{
+	port->MODER &= ~(0x03 << (2 * pin));
+	port->MODER |= mode << (2 * pin);
+}
+
+void gpio_dout(GPIO_TypeDef *port, uint32_t pin, uint32_t val)
+{
+	port->BSRR |= (1 << (val ? pin : pin + 16));
+}
+
+uint32_t gpio_din(GPIO_TypeDef *port, uint32_t pin)
+{
+	return port->IDR & (1 << pin);
+}