136 lines
4.4 KiB
C
136 lines
4.4 KiB
C
#include "usbd_cdc_if.h"
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#include "stm32f7xx_hal.h"
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extern USBD_HandleTypeDef hUsbDevice;
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volatile uint8_t cdc_streaming = 1; /* auto-stream */
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static volatile uint8_t cdc_port_open = 0; /* set when host asserts DTR */
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volatile uint8_t cdc_arm_request = 0; /* set by A command */
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volatile uint8_t cdc_disarm_request = 0; /* set by D command */
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static uint8_t UserRxBuffer[256];
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static uint8_t UserTxBuffer[256];
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/*
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* Betaflight-proven DFU reboot:
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* 1. Write magic to RTC backup register (persists across soft reset)
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* 2. NVIC_SystemReset() — clean hardware reset
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* 3. Early startup checks magic, clears it, jumps to system bootloader
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*
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* The magic check happens in checkForBootloader() called from main.c
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* before any peripheral init.
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*/
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#define BOOTLOADER_MAGIC 0xDEADBEEF
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static void request_bootloader(void) {
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/* Betaflight-proven: write magic, disable IRQs, reset.
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* checkForBootloader() runs on next boot before anything else. */
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__HAL_RCC_PWR_CLK_ENABLE();
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HAL_PWR_EnableBkUpAccess();
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__HAL_RCC_RTC_ENABLE();
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/* Write magic to RTC backup register 0 */
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RTC->BKP0R = BOOTLOADER_MAGIC;
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__disable_irq();
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NVIC_SystemReset();
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}
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/*
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* Call this VERY early in main(), before HAL_Init().
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* Checks RTC backup register for magic value left by request_bootloader().
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* If found: clear magic, jump to STM32F7 system bootloader at 0x1FF00000.
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*/
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void checkForBootloader(void) {
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/*
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* Betaflight-proven bootloader jump for STM32F7.
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* Called VERY early, before HAL_Init/caches/clocks.
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* At this point only RCC PWR is needed to read RTC backup regs.
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*/
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/* Enable backup domain access to read RTC backup register */
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__HAL_RCC_PWR_CLK_ENABLE();
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HAL_PWR_EnableBkUpAccess();
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__HAL_RCC_RTC_ENABLE();
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uint32_t magic = RTC->BKP0R;
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if (magic != BOOTLOADER_MAGIC) {
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return; /* Normal boot */
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}
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/* Write POST marker (Betaflight does this so SystemInit can
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* do a second reset if needed — we just clear it) */
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RTC->BKP0R = 0;
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/* Jump to STM32F7 system bootloader at 0x1FF00000.
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* Exactly as Betaflight does it — no cache/VTOR/MEMRMP games needed
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* because we run before any of that is configured. */
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__HAL_RCC_SYSCFG_CLK_ENABLE();
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__set_MSP(*(uint32_t *)0x1FF00000);
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((void (*)(void))(*(uint32_t *)0x1FF00004))();
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while (1);
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}
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static int8_t CDC_Init(void) {
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USBD_CDC_SetTxBuffer(&hUsbDevice, UserTxBuffer, 0);
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USBD_CDC_SetRxBuffer(&hUsbDevice, UserRxBuffer);
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USBD_CDC_ReceivePacket(&hUsbDevice);
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/* Reset TxState so CDC_Transmit works after host (re)connects.
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* Without this, if transmits happen before host opens port,
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* TxState stays BUSY forever since host never ACKs. */
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USBD_CDC_HandleTypeDef *hcdc = (USBD_CDC_HandleTypeDef *)hUsbDevice.pClassData;
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if (hcdc) hcdc->TxState = 0;
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return USBD_OK;
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}
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static int8_t CDC_DeInit(void) { return USBD_OK; }
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static int8_t CDC_Control(uint8_t cmd, uint8_t *pbuf, uint16_t length) {
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(void)pbuf; (void)length;
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if (cmd == 0x22) { /* CDC_SET_CONTROL_LINE_STATE — host opened port */
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cdc_port_open = 1;
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cdc_streaming = 1;
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}
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return USBD_OK;
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}
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static int8_t CDC_Receive(uint8_t *buf, uint32_t *len) {
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if (*len >= 1 && buf[0] == 'S') {
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cdc_streaming = !cdc_streaming; /* Toggle streaming */
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}
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if (*len >= 1 && buf[0] == 'A') {
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cdc_arm_request = 1; /* Arm balance — processed in main loop */
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}
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if (*len >= 1 && buf[0] == 'D') {
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cdc_disarm_request = 1; /* Disarm — processed in main loop */
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}
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if (*len >= 1 && buf[0] == 'R') {
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request_bootloader(); /* Sets magic + resets — never returns */
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}
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USBD_CDC_SetRxBuffer(&hUsbDevice, UserRxBuffer);
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USBD_CDC_ReceivePacket(&hUsbDevice);
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return USBD_OK;
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}
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USBD_CDC_ItfTypeDef USBD_CDC_fops = { CDC_Init, CDC_DeInit, CDC_Control, CDC_Receive };
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uint8_t CDC_Transmit(uint8_t *buf, uint16_t len) {
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USBD_CDC_HandleTypeDef *hcdc = (USBD_CDC_HandleTypeDef *)hUsbDevice.pClassData;
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if (hcdc == NULL) return USBD_FAIL;
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if (hcdc->TxState != 0) {
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/* If stuck busy (no host ACK), force reset after a while */
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static uint32_t busy_count = 0;
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if (++busy_count > 100) { hcdc->TxState = 0; busy_count = 0; }
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return USBD_BUSY;
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}
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USBD_CDC_SetTxBuffer(&hUsbDevice, buf, len);
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return USBD_CDC_TransmitPacket(&hUsbDevice);
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}
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