1 files changed, 94 insertions, 0 deletions
diff --git a/usb/usb.c b/usb/usb.c
new file mode 100644
index 0000000..ebd3179
--- /dev/null
+++ b/usb/usb.c
@@ -0,0 +1,94 @@
+#include <reg/sim.h>
+#include <reg/usbotg.h>
+#include <reg/gpio.h>
+#include <stddef.h>
+
+#include "usb.h"
+#include "bdt.h"
+#include "endpt0.h"
+#include "endpt1.h"
+
+#define USBFRAC_VAL 1 /* 72 MHz * 2 = 144 MHz (Top of Fraction) */
+#define USBDIV_VAL 2 /* 144 MHz / 3 = 48 MHz (Bottom of Fraction) */
+
+/* TODO: Move this to lib somewhere */
+#define CLRPEND(n) REG_32(0xE000E280 + 4 * (n))
+#define ISR_CLRPEND(i) CLRPEND((i) / 32) = BV((i) % 32);
+
+#define SETENA(n) REG_32(0xE000E100 + 4 * (n))
+#define ISR_SETENA(i) SETENA((i) / 32) = BV((i) % 32);
+
+
+__attribute__  ((aligned(512)))
+struct usb0_bd usb_bdt[16 * 4]; /* TODO: Only use the number of endpoints that are needed */
+
+/* usb_setup: Setup function for USB subsystem */
+void usb_setup(void)
+{
+	/* Clock Setup */
+	SET_BIT(SIM_SOPT2, SOPT2_USBSRC);
+	SET_MASKED(SIM_CLKDIV2, CLKDIV2_USBDIV_M | BV(CLKDIV2_USBFRAC),
+		   USBDIV_VAL << CLKDIV2_USBDIV | USBFRAC_VAL << CLKDIV2_USBFRAC);
+	SET_BIT(SIM_SCGC4, SCGC4_USBOTG);
+
+	/* Reset USB and wait more than 2 USB clock cycles */
+	SET_BIT(USB0_USBTRC0, USBTRC0_USBRESET);
+	for (int i = 0; i < 5; i++)
+		;
+
+	/* 512 bit aligned BDT address */
+	USB0_BDTPAGE1 = (uintptr_t)usb_bdt >> 8 & 0xff;
+	USB0_BDTPAGE2 = (uintptr_t)usb_bdt >> 16 & 0xff;
+	USB0_BDTPAGE3 = (uintptr_t)usb_bdt >> 24 & 0xff;
+
+	/* Initial Configuration */
+	SET_MASKED(USB0_USBCTRL, BV(USBCTRL_SUSP) | BV(USBCTRL_PDE), 0);
+	SET_BIT(USB0_CONTROL, CONTROL_DPPULLUPNONOTG);
+	SET_BIT(USB0_INTEN, INTEN_USBRSTEN);
+
+	/* NVIC Enable interrupt */
+	ISR_CLRPEND(73);
+	ISR_SETENA(73);
+
+	/* Enable USB */
+	USB0_CTL = BV(CTL_USBENSOFEN);
+}
+
+/* i_usbrst: Handler for USBRST USB interrupt */
+static void i_usbrst(void)
+{
+	SET_BIT(USB0_CTL, CTL_ODDRST);
+
+	usb_endpt0_enable();
+	usb_endpt1_disable();
+
+	USB0_ADDR = 0;
+
+	SET_BIT(USB0_INTEN, INTEN_TOKDNEEN);
+}
+
+/* i_tokdne: Handler for TOKDNE USB interrupt */
+static void i_tokdne(void)
+{
+	uint8_t stat = USB0_STAT;
+
+	switch (GET_BITS(stat, STAT_ENDP)) {
+	case 0: usb_endpt0_token(stat); break;
+	case 1: usb_endpt1_token(stat); break;
+	}
+}
+
+/* usb_isr: interrupt service routine for the USB FS SIE */
+void usb_isr(void)
+{
+	uint8_t stat = USB0_ISTAT;
+
+	if (IS_BIT_SET(stat, ISTAT_TOKDNE)) {
+		i_tokdne();
+		USB0_ISTAT = BV(ISTAT_TOKDNE);
+	}
+	if (IS_BIT_SET(stat, ISTAT_USBRST)) {
+		i_usbrst();
+		USB0_ISTAT = BV(ISTAT_USBRST);
+	}
+}