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/*
* usb/usb.c -- USB 2.0 implementation
*
* Copyright (C) 2016-2017 Tomasz Kramkowski <tk@the-tk.com>
*
* 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 <http://www.gnu.org/licenses/>.
*/
#include <cm4.h>
#include <reg/gpio.h>
#include <reg/sim.h>
#include <reg/usbotg.h>
#include <stddef.h>
#include "../uart.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) */
__attribute__ ((aligned(512)))
volatile struct usb0_bd usb_bdt[2][2][2];
/* 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);
USB0_INTEN = BV(INTEN_STALLEN) | BV(INTEN_ERROREN) | BV(INTEN_USBRSTEN);
/* NVIC Enable interrupt */
ISR_CLRPEND(73);
ISR_SETENA(73);
INTPRI(73) = 0x00;
/* 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 (GET_BIT(stat, ISTAT_STALL)) {
uart_puts("INT: stall");
USB0_ISTAT = BV(ISTAT_STALL);
}
if (GET_BIT(stat, ISTAT_TOKDNE)) {
i_tokdne();
USB0_ISTAT = BV(ISTAT_TOKDNE);
}
if (GET_BIT(stat, ISTAT_ERROR)) {
uart_printf("INT: error (0x%x)\n", (unsigned)USB0_ERRSTAT);
USB0_ERRSTAT = USB0_ERRSTAT;
USB0_ISTAT = BV(ISTAT_ERROR);
}
if (GET_BIT(stat, ISTAT_USBRST)) {
i_usbrst();
USB0_ISTAT = BV(ISTAT_USBRST);
}
}
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