Low-level ESP32 bootloader SLIP communication protocol

src/drivers/esp32/interface/esp_slip.h

@@ -0,0 +1,89 @@
+/**
+ * ,---------,       ____  _ __
+ * |  ,-^-,  |      / __ )(_) /_______________ _____  ___
+ * | (  O  ) |     / __  / / __/ ___/ ___/ __ `/_  / / _ \
+ * | / ,--´  |    / /_/ / / /_/ /__/ /  / /_/ / / /_/  __/
+ *    +------`   /_____/_/\__/\___/_/   \__,_/ /___/\___/
+ *
+ * Crazyflie control firmware
+ *
+ * Copyright (C) 2021 Bitcraze AB
+ *
+ * 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, in version 3.
+ *
+ * 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/>.
+ *
+ * @file esp_slip.h
+ * Protocol for assembling, sending, receiving and decoding SLIP packets to/from the ESP32 ROM bootloader
+ *  
+ */
+
+#pragma once
+
+#include <stdbool.h>
+#include <stdint.h>
+
+#define ESP_MTU 4000
+
+/* Commands */
+#define DIR_CMD 0x00
+#define FLASH_BEGIN 0x02
+#define FLASH_DATA 0x03
+#define FLASH_END 0x04
+#define SYNC 0x08
+#define SPI_FLASH_MD5 0x13
+#define ERASE_FLASH 0xd0
+#define READ_FLASH 0xd2
+#define CHANGE_BAUDRATE 0x0f
+#define SPI_ATTACH 0x0d
+
+typedef void (*coms_sendbuffer_t)(uint32_t size, uint8_t *data);
+typedef bool (*coms_getDataWithTimeout_t)(uint8_t *c, const uint32_t timeoutTicks);
+
+typedef enum
+{
+  SLIP_DECODING,
+  SLIP_SUCCESS,
+  SLIP_ERROR
+} slipDecoderStatus_t;
+
+typedef struct
+{
+  uint8_t direction;
+  uint8_t command;
+  uint16_t dataSize;
+  uint32_t checksum;
+} __attribute__((packed)) esp_slip_send_packet;
+
+typedef struct
+{
+  uint8_t direction;
+  uint8_t command;
+  uint16_t dataSize;
+  uint32_t value; // only for READ_REG command
+  uint8_t data[256];
+  uint8_t status;
+  uint8_t error;
+} __attribute__((packed)) esp_slip_receive_packet;
+
+/**
+* @brief Called to send a SLIP packet to the ESP, and receive the response.
+*
+* @param *sendBuffer Pointer to the to be sent buffer
+* @param *receiverPacket Pointer to receiver packet struct, which will be filled with the response
+* @param *senderPacket Pointer to sender packet struct, which will be used to fill the send buffer header
+* @param sendBufferFunction Function pointer to the function that sends the buffer (split into pages) to the ESP
+* @param getDataWithTimeoutFunction Function pointer to the function that receives data (byte by byte) from the ESP
+* @param timeoutTicks Number of ticks to wait for a response from the ESP
+*
+* @return true if ESP responds with a status byte indicating success.
+**/
+bool espSlipExchange(uint8_t *sendBuffer, esp_slip_receive_packet *receiverPacket, esp_slip_send_packet *senderPacket, coms_sendbuffer_t sendBufferFunction, coms_getDataWithTimeout_t getDataWithTimeout, uint32_t timeoutTicks);