mongoose/examples/ti/ek-tm4c1294xl-make-baremetal-builtin/hal.h

// Copyright (c) 2022 Cesanta Software Limited
// All rights reserved
// https://www.ti.com/lit/pdf/spms433

#pragma once

#include "TM4C1294NCPDT.h"

#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>

#define BIT(x) (1UL << (x))
#define SETBITS(R, CLEARMASK, SETMASK) (R) = ((R) & ~(CLEARMASK)) | (SETMASK)
#define PIN(bank, num) ((bank << 8) | (num))
#define PINNO(pin) (pin & 255)
#define PINBANK(pin) pinbank(pin >> 8)
// This MCU doesn't have GPIOI nor GPIOO
static inline unsigned int pinbank(unsigned int bank) {
  bank = bank > 'O' ? bank - 2 : bank > 'I' ? bank - 1 : bank;
  return bank - 'A';
}

// 5.5, Table 5-12: configure flash (and EEPROM) timing in accordance to clock
// freq
enum {
  PLL_CLK = 25,
  PLL_M = 96,
  PLL_N = 5,
  PLL_Q = 1,
  PSYSDIV = 4
};  // Run at 120 Mhz
#define PLL_FREQ (PLL_CLK * PLL_M / PLL_N / PLL_Q / PSYSDIV)
#define FLASH_CLKHIGH 6
#define FLASH_WAITST 5
#define SYS_FREQUENCY (PLL_FREQ * 1000000)

static inline void spin(volatile uint32_t count) {
  while (count--) (void) 0;
}

enum { GPIO_MODE_INPUT, GPIO_MODE_OUTPUT, GPIO_MODE_AF, GPIO_MODE_ANALOG };
enum { GPIO_OTYPE_PUSH_PULL, GPIO_OTYPE_OPEN_DRAIN };
enum { GPIO_SPEED_LOW, GPIO_SPEED_HIGH };
enum { GPIO_PULL_NONE, GPIO_PULL_UP, GPIO_PULL_DOWN };
#define GPIO(bank) ((GPIOA_AHB_Type *) (GPIOA_AHB_BASE + 0x1000U * (bank)))

// CMSIS header forces 0xFF mask when writing to DATA (see 10.6 in datasheet)
// and does not seem to support that feature for writing by defining RESERVED0
// to read-only
static inline void gpio_toggle(uint16_t pin) {
  GPIOA_AHB_Type *gpio = GPIO(PINBANK(pin));
  volatile uint32_t *GPIODATA = (volatile uint32_t *) gpio->RESERVED0;
  uint8_t mask = BIT(PINNO(pin));
  GPIODATA[mask] ^= mask;
}
static inline int gpio_read(uint16_t pin) {
  GPIOA_AHB_Type *gpio = GPIO(PINBANK(pin));
  volatile uint32_t *GPIODATA = (volatile uint32_t *) gpio->RESERVED0;
  uint8_t mask = BIT(PINNO(pin));
  return GPIODATA[mask] ? 1 : 0;
}
static inline void gpio_write(uint16_t pin, bool val) {
  GPIOA_AHB_Type *gpio = GPIO(PINBANK(pin));
  volatile uint32_t *GPIODATA = (volatile uint32_t *) gpio->RESERVED0;
  uint8_t mask = BIT(PINNO(pin));
  GPIODATA[mask] = val ? mask : 0;
}
static inline void gpio_init(uint16_t pin, uint8_t mode, uint8_t type,
                             uint8_t speed, uint8_t pull, uint8_t af) {
  GPIOA_AHB_Type *gpio = GPIO(PINBANK(pin));
  uint8_t n = (uint8_t) (PINNO(pin));
  SYSCTL->RCGCGPIO |= BIT(PINBANK(pin));  // Enable GPIO clock
  if (mode == GPIO_MODE_ANALOG) {
    gpio->AMSEL |= BIT(PINNO(pin));
    return;
  }
  if (mode == GPIO_MODE_INPUT) {
    gpio->DIR &= ~BIT(PINNO(pin));
  } else if (mode == GPIO_MODE_OUTPUT) {
    gpio->DIR |= BIT(PINNO(pin));
  } else {  // GPIO_MODE_AF
    SETBITS(gpio->PCTL, 15UL << ((n & 7) * 4),
            ((uint32_t) af) << ((n & 7) * 4));
    gpio->AFSEL |= BIT(PINNO(pin));
  }
  gpio->DEN |= BIT(PINNO(pin));  // Enable pin as digital function
  if (type == GPIO_OTYPE_OPEN_DRAIN)
    gpio->ODR |= BIT(PINNO(pin));
  else  // GPIO_OTYPE_PUSH_PULL
    gpio->ODR &= ~BIT(PINNO(pin));
  if (speed == GPIO_SPEED_LOW)
    gpio->SLR |= BIT(PINNO(pin));
  else  // GPIO_SPEED_HIGH
    gpio->SLR &= ~BIT(PINNO(pin));
  if (pull == GPIO_PULL_UP) {
    gpio->PUR |= BIT(PINNO(pin));  // setting one...
  } else if (pull == GPIO_PULL_DOWN) {
    gpio->PDR |= BIT(PINNO(pin));  // ...just clears the other
  } else {
    gpio->PUR &= ~BIT(PINNO(pin));
    gpio->PDR &= ~BIT(PINNO(pin));
  }
}
static inline void gpio_input(uint16_t pin) {
  gpio_init(pin, GPIO_MODE_INPUT, GPIO_OTYPE_PUSH_PULL, GPIO_SPEED_HIGH,
            GPIO_PULL_NONE, 0);
}
static inline void gpio_output(uint16_t pin) {
  gpio_init(pin, GPIO_MODE_OUTPUT, GPIO_OTYPE_PUSH_PULL, GPIO_SPEED_HIGH,
            GPIO_PULL_NONE, 0);
}

static inline void gpio_irq_attach(uint16_t pin) {
  uint8_t irqvecs[] = {16, 17, 18, 19, 20, 30, 31, 32,
                       51, 52, 53, 72, 73, 76, 84};
  GPIOA_AHB_Type *gpio = GPIO(PINBANK(pin));
  gpio->IS &= ~BIT(PINNO(pin));        // edge sensitive
  gpio->IBE |= BIT(PINNO(pin));        // both edges
  gpio->IM |= BIT(PINNO(pin));         // enable pin irq
  int irqvec = irqvecs[PINBANK(pin)];  // IRQ vector index, 2.5.2
  NVIC_SetPriority(irqvec, 3);
  NVIC_EnableIRQ(irqvec);
}

#ifndef UART_DEBUG
#define UART_DEBUG UART0
#endif

#define UART_OFFSET 0x1000
#define UART(N) ((UART0_Type *) (UART0_BASE + UART_OFFSET * (N)))
#define UARTNO(u) ((uint8_t) (((unsigned int) (u) -UART0_BASE) / UART_OFFSET))

static inline void uart_init(UART0_Type *uart, unsigned long baud) {
  uint8_t af = 1;           // Alternate function
  uint16_t rx = 0, tx = 0;  // pins
  uint8_t uartno = UARTNO(uart);

  SYSCTL->RCGCUART |= BIT(uartno);  // Enable peripheral clock

  if (uart == UART0) tx = PIN('A', 0), rx = PIN('A', 1);
  if (uart == UART1) tx = PIN('B', 0), rx = PIN('B', 1);
  if (uart == UART2) tx = PIN('A', 6), rx = PIN('A', 7);  // or PD4, PD5...

  gpio_init(tx, GPIO_MODE_AF, GPIO_OTYPE_PUSH_PULL, GPIO_SPEED_HIGH, 0, af);
  gpio_init(rx, GPIO_MODE_AF, GPIO_OTYPE_PUSH_PULL, GPIO_SPEED_HIGH, 0, af);
  // (16.3.2) ClkDiv = 16 (HSE=0)
  // BRD = BRDI + BRDF = UARTSysClk / (ClkDiv * Baud Rate)
  // UARTFBRD[DIVFRAC] = integer(BRDF * 64 + 0.5)
  // must write in this order
  uart->CTL = 0;                             // Disable this UART, clear HSE
  uart->IBRD = SYS_FREQUENCY / (16 * baud);  // Baud rate, integer part
  uart->FBRD = ((SYS_FREQUENCY % (16 * baud)) >> 26) &
               0x3F;                      // Baud rate, fractional part
  uart->LCRH = (3 << 5);                  // 8N1, no FIFOs;
  uart->CTL |= BIT(0) | BIT(9) | BIT(8);  // Set UARTEN, RXE, TXE
}
static inline void uart_write_byte(UART0_Type *uart, uint8_t byte) {
  uart->DR = byte;
  while ((uart->FR & BIT(7)) == 0) spin(1);
}
static inline void uart_write_buf(UART0_Type *uart, char *buf, size_t len) {
  while (len-- > 0) uart_write_byte(uart, *(uint8_t *) buf++);
}
static inline int uart_read_ready(UART0_Type *uart) {
  return uart->FR & BIT(6);  // If RXFF bit is set, data is ready
}
static inline uint8_t uart_read_byte(UART0_Type *uart) {
  return (uint8_t) (uart->DR & 0xFF);
}

// Helper macro for reading pre-flashed MAC from user registers
#define READ_PREFLASHED_MAC()                                               \
  {                                                                         \
    (FLASH_CTRL->USERREG0 >> 0) & 0xFF, (FLASH_CTRL->USERREG0 >> 8) & 0xFF, \
        (FLASH_CTRL->USERREG0 >> 16) & 0xFF,                                \
        (FLASH_CTRL->USERREG1 >> 0) & 0xFF,                                 \
        (FLASH_CTRL->USERREG1 >> 8) & 0xFF,                                 \
        (FLASH_CTRL->USERREG1 >> 16) & 0xFF                                 \
  }