mdk.h

// Copyright (c) 2022 Cesanta
// All rights reserved

#pragma once

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

#define BIT(x) ((uint32_t) 1U << (x))
#define REG(x) ((volatile uint32_t *) (x))

#define C3_SYSTEM 0x600c0000
#define C3_SENSITIVE 0x600c1000
#define C3_INTERRUPT 0x600c2000
#define C3_EXTMEM 0x600c4000
#define C3_MMU_TABLE 0x600c5000
#define C3_AES 0x6003a000
#define C3_SHA 0x6003b000
#define C3_RSA 0x6003c000
#define C3_HMAC 0x6003e000
#define C3_DIGITAL_SIGNATURE 0x6003d000
#define C3_GDMA 0x6003f000
#define C3_ASSIST_DEBUG 0x600ce000
#define C3_DEDICATED_GPIO 0x600cf000
#define C3_WORLD_CNTL 0x600d0000
#define C3_DPORT_END 0x600d3FFC
#define C3_UART 0x60000000
#define C3_SPI1 0x60002000
#define C3_SPI0 0x60003000
#define C3_GPIO 0x60004000
#define C3_FE2 0x60005000
#define C3_FE 0x60006000
#define C3_RTCCNTL 0x60008000
#define C3_IO_MUX 0x60009000
#define C3_RTC_I2C 0x6000e000
#define C3_UART1 0x60010000
#define C3_I2C_EXT 0x60013000
#define C3_UHCI0 0x60014000
#define C3_RMT 0x60016000
#define C3_LEDC 0x60019000
#define C3_EFUSE 0x60008800
#define C3_NRX 0x6001CC00
#define C3_BB 0x6001D000
#define C3_TIMERGROUP0 0x6001F000
#define C3_TIMERGROUP1 0x60020000
#define C3_SYSTIMER 0x60023000
#define C3_SPI2 0x60024000
#define C3_SYSCON 0x60026000
#define C3_APB_CTRL 0x60026000
#define C3_TWAI 0x6002B000
#define C3_I2S0 0x6002D000
#define C3_APB_SARADC 0x60040000
#define C3_AES_XTS 0x600CC000

enum { GPIO_OUT_EN = 8, GPIO_OUT_FUNC = 341, GPIO_IN_FUNC = 85 };

// Perform `count` "NOP" operations
static inline void spin(volatile unsigned long count) {
  while (count--) asm volatile("nop");
}

static inline uint64_t systick(void) {
  REG(C3_SYSTIMER)[1] = BIT(30);  // TRM 10.5
  spin(1);
  return ((uint64_t) REG(C3_SYSTIMER)[16] << 32) | REG(C3_SYSTIMER)[17];
}

static inline uint64_t uptime_us(void) {
  return systick() >> 4;
}

static inline void delay_us(unsigned long us) {
  uint64_t until = uptime_us() + us;
  while (uptime_us() < until) spin(1);
}

static inline void delay_ms(unsigned long ms) {
  delay_us(ms * 1000);
}

static inline void wdt_disable(void) {
  REG(C3_RTCCNTL)[42] = 0x50d83aa1;  // Disable write protection
  // REG(C3_RTCCNTL)[36] &= BIT(31);    // Disable RTC WDT
  REG(C3_RTCCNTL)[36] = 0;  // Disable RTC WDT
  REG(C3_RTCCNTL)[35] = 0;  // Disable

  // bootloader_super_wdt_auto_feed()
  REG(C3_RTCCNTL)[44] = 0x8F1D312A;
  REG(C3_RTCCNTL)[43] |= BIT(31);
  REG(C3_RTCCNTL)[45] = 0;

  REG(C3_TIMERGROUP0)[63] &= ~BIT(9);  // TIMG_REGCLK -> disable TIMG_WDT_CLK
  REG(C3_TIMERGROUP0)[18] = 0;         // Disable TG0 WDT
  REG(C3_TIMERGROUP1)[18] = 0;         // Disable TG1 WDT
}

static inline void wifi_get_mac_addr(uint8_t mac[6]) {
  uint32_t a = REG(C3_EFUSE)[17], b = REG(C3_EFUSE)[18];
  mac[0] = (b >> 8) & 255, mac[1] = b & 255, mac[2] = (uint8_t) (a >> 24) & 255;
  mac[3] = (a >> 16) & 255, mac[4] = (a >> 8) & 255, mac[5] = a & 255;
}

static inline void soc_init(void) {
  // Init clock. TRM 6.2.4.1
  REG(C3_SYSTEM)[2] &= ~3U;
  REG(C3_SYSTEM)[2] |= BIT(0) | BIT(2);
  REG(C3_SYSTEM)[22] = BIT(19) | (40U << 12) | BIT(10);
  // REG(C3_RTCCNTL)[47] = 0; // RTC_APB_FREQ_REG -> freq >> 12
  ((void (*)(int)) 0x40000588)(160);  // ets_update_cpu_frequency(160)

#if 0
  // Configure system clock timer, TRM 8.3.1, 8.9
  REG(C3_TIMERGROUP0)[1] = REG(C3_TIMERGROUP0)[2] = 0UL;  // Reset LO and HI
  REG(C3_TIMERGROUP0)[8] = 0;                             // Trigger reload
  REG(C3_TIMERGROUP0)[0] = (83U << 13) | BIT(12) | BIT(29) | BIT(30) | BIT(31);
#endif
}

// API GPIO

static inline void gpio_output_enable(int pin, bool enable) {
  REG(C3_GPIO)[GPIO_OUT_EN] &= ~BIT(pin);
  REG(C3_GPIO)[GPIO_OUT_EN] |= (enable ? 1U : 0U) << pin;
}

static inline void gpio_output(int pin) {
  REG(C3_GPIO)[GPIO_OUT_FUNC + pin] = BIT(9) | 128;  // Simple out, TRM 5.5.3
  gpio_output_enable(pin, 1);
}

static inline void gpio_write(int pin, bool value) {
  REG(C3_GPIO)[1] &= ~BIT(pin);                 // Clear first
  REG(C3_GPIO)[1] |= (value ? 1U : 0U) << pin;  // Then set
}

static inline void gpio_toggle(int pin) {
  REG(C3_GPIO)[1] ^= BIT(pin);
}

static inline void gpio_input(int pin) {
  gpio_output_enable(pin, 0);                 // Disable output
  REG(C3_IO_MUX)[1 + pin] = BIT(9) | BIT(8);  // Enable pull-up
}

static inline bool gpio_read(int pin) {
  return REG(C3_GPIO)[15] & BIT(pin) ? 1 : 0;
}

// API SPI

struct spi {
  int miso, mosi, clk, cs;  // Pins
  int spin;                 // Number of NOP spins for bitbanging
};

static inline void spi_begin(struct spi *spi) {
  gpio_write(spi->cs, 0);
}

static inline void spi_end(struct spi *spi) {
  gpio_write(spi->cs, 1);
}

static inline bool spi_init(struct spi *spi) {
  if (spi->miso < 0 || spi->mosi < 0 || spi->clk < 0) return false;
  gpio_input(spi->miso);
  gpio_output(spi->mosi);
  gpio_output(spi->clk);
  if (spi->cs >= 0) {
    gpio_output(spi->cs);
    gpio_write(spi->cs, 1);
  }
  return true;
}

// Send a byte, and return a received byte
static inline unsigned char spi_txn(struct spi *spi, unsigned char tx) {
  unsigned count = spi->spin <= 0 ? 9 : (unsigned) spi->spin;
  unsigned char rx = 0;
  for (int i = 0; i < 8; i++) {
    gpio_write(spi->mosi, tx & 0x80);   // Set mosi
    spin(count);                        // Wait half cycle
    gpio_write(spi->clk, 1);            // Clock high
    rx = (unsigned char) (rx << 1);     // "rx <<= 1" gives warning??
    if (gpio_read(spi->miso)) rx |= 1;  // Read miso
    spin(count);                        // Wait half cycle
    gpio_write(spi->clk, 0);            // Clock low
    tx = (unsigned char) (tx << 1);     // Again, avoid warning
  }
  return rx;  // Return the received byte
}

// API WS2812
static inline void ws2812_show(int pin, const uint8_t *buf, size_t len) {
  unsigned long delays[2] = {2, 6};
  for (size_t i = 0; i < len; i++) {
    for (uint8_t mask = 0x80; mask; mask >>= 1) {
      int i1 = buf[i] & mask ? 1 : 0, i2 = i1 ^ 1;  // This takes some cycles
      gpio_write(pin, 1);
      spin(delays[i1]);
      gpio_write(pin, 0);
      spin(delays[i2]);
    }
  }
}

// Default settings for board peripherals

#ifndef LED1
#define LED1 2  // Default LED pin
#endif

#ifndef BTN1
#define BTN1 9  // Default user button pin
#endif