259 lines
7.5 KiB
C
259 lines
7.5 KiB
C
#pragma once
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#include "crc.h"
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#define SPI_TIMEOUT_US 10000U
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// got max rate from hitting a non-existent endpoint
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// in a tight loop, plus some buffer
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#define SPI_IRQ_RATE 16000U
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#ifdef STM32H7
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#define SPI_BUF_SIZE 2048U
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// H7 DMA2 located in D2 domain, so we need to use SRAM1/SRAM2
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__attribute__((section(".sram12"))) uint8_t spi_buf_rx[SPI_BUF_SIZE];
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__attribute__((section(".sram12"))) uint8_t spi_buf_tx[SPI_BUF_SIZE];
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#else
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#define SPI_BUF_SIZE 1024U
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uint8_t spi_buf_rx[SPI_BUF_SIZE];
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uint8_t spi_buf_tx[SPI_BUF_SIZE];
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#endif
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#define SPI_CHECKSUM_START 0xABU
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#define SPI_SYNC_BYTE 0x5AU
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#define SPI_HACK 0x79U
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#define SPI_DACK 0x85U
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#define SPI_NACK 0x1FU
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// SPI states
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enum {
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SPI_STATE_HEADER,
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SPI_STATE_HEADER_ACK,
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SPI_STATE_HEADER_NACK,
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SPI_STATE_DATA_RX,
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SPI_STATE_DATA_RX_ACK,
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SPI_STATE_DATA_TX
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};
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bool spi_tx_dma_done = false;
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uint8_t spi_state = SPI_STATE_HEADER;
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uint8_t spi_endpoint;
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uint16_t spi_data_len_mosi;
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uint16_t spi_data_len_miso;
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uint16_t spi_checksum_error_count = 0;
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bool spi_can_tx_ready = false;
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const char version_text[] = "VERSION";
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#define SPI_HEADER_SIZE 7U
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// low level SPI prototypes
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void llspi_init(void);
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void llspi_mosi_dma(uint8_t *addr, int len);
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void llspi_miso_dma(uint8_t *addr, int len);
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void can_tx_comms_resume_spi(void) {
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spi_can_tx_ready = true;
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}
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uint16_t spi_version_packet(uint8_t *out) {
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// this protocol version request is a stable portion of
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// the panda's SPI protocol. its contents match that of the
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// panda USB descriptors and are sufficent to list/enumerate
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// a panda, determine panda type, and bootstub status.
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// the response is:
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// VERSION + 2 byte data length + data + CRC8
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// echo "VERSION"
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(void)memcpy(out, version_text, 7);
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// write response
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uint16_t data_len = 0;
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uint16_t data_pos = 7U + 2U;
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// write serial
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#ifdef UID_BASE
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(void)memcpy(&out[data_pos], ((uint8_t *)UID_BASE), 12);
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data_len += 12U;
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#endif
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// HW type
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out[data_pos + data_len] = hw_type;
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data_len += 1U;
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// bootstub
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out[data_pos + data_len] = USB_PID & 0xFFU;
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data_len += 1U;
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// SPI protocol version
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out[data_pos + data_len] = 0x2;
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data_len += 1U;
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// data length
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out[7] = data_len & 0xFFU;
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out[8] = (data_len >> 8) & 0xFFU;
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// CRC8
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uint16_t resp_len = data_pos + data_len;
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out[resp_len] = crc_checksum(out, resp_len, 0xD5U);
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resp_len += 1U;
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return resp_len;
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}
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void spi_init(void) {
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// platform init
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llspi_init();
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// Start the first packet!
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spi_state = SPI_STATE_HEADER;
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llspi_mosi_dma(spi_buf_rx, SPI_HEADER_SIZE);
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}
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bool validate_checksum(const uint8_t *data, uint16_t len) {
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// TODO: can speed this up by casting the bulk to uint32_t and xor-ing the bytes afterwards
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uint8_t checksum = SPI_CHECKSUM_START;
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for(uint16_t i = 0U; i < len; i++){
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checksum ^= data[i];
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}
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return checksum == 0U;
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}
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void spi_rx_done(void) {
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uint16_t response_len = 0U;
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uint8_t next_rx_state = SPI_STATE_HEADER_NACK;
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bool checksum_valid = false;
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// parse header
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spi_endpoint = spi_buf_rx[1];
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spi_data_len_mosi = (spi_buf_rx[3] << 8) | spi_buf_rx[2];
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spi_data_len_miso = (spi_buf_rx[5] << 8) | spi_buf_rx[4];
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if (memcmp(spi_buf_rx, version_text, 7) == 0) {
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response_len = spi_version_packet(spi_buf_tx);
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next_rx_state = SPI_STATE_HEADER_NACK;;
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} else if (spi_state == SPI_STATE_HEADER) {
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checksum_valid = validate_checksum(spi_buf_rx, SPI_HEADER_SIZE);
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if ((spi_buf_rx[0] == SPI_SYNC_BYTE) && checksum_valid) {
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// response: ACK and start receiving data portion
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spi_buf_tx[0] = SPI_HACK;
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next_rx_state = SPI_STATE_HEADER_ACK;
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response_len = 1U;
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} else {
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// response: NACK and reset state machine
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print("- incorrect header sync or checksum "); hexdump(spi_buf_rx, SPI_HEADER_SIZE);
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spi_buf_tx[0] = SPI_NACK;
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next_rx_state = SPI_STATE_HEADER_NACK;
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response_len = 1U;
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}
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} else if (spi_state == SPI_STATE_DATA_RX) {
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// We got everything! Based on the endpoint specified, call the appropriate handler
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bool response_ack = false;
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checksum_valid = validate_checksum(&(spi_buf_rx[SPI_HEADER_SIZE]), spi_data_len_mosi + 1U);
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if (checksum_valid) {
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if (spi_endpoint == 0U) {
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if (spi_data_len_mosi >= sizeof(ControlPacket_t)) {
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ControlPacket_t ctrl;
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(void)memcpy(&ctrl, &spi_buf_rx[SPI_HEADER_SIZE], sizeof(ControlPacket_t));
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response_len = comms_control_handler(&ctrl, &spi_buf_tx[3]);
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response_ack = true;
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} else {
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print("SPI: insufficient data for control handler\n");
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}
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} else if ((spi_endpoint == 1U) || (spi_endpoint == 0x81U)) {
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if (spi_data_len_mosi == 0U) {
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response_len = comms_can_read(&(spi_buf_tx[3]), spi_data_len_miso);
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response_ack = true;
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} else {
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print("SPI: did not expect data for can_read\n");
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}
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} else if (spi_endpoint == 2U) {
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comms_endpoint2_write(&spi_buf_rx[SPI_HEADER_SIZE], spi_data_len_mosi);
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response_ack = true;
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} else if (spi_endpoint == 3U) {
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if (spi_data_len_mosi > 0U) {
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if (spi_can_tx_ready) {
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spi_can_tx_ready = false;
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comms_can_write(&spi_buf_rx[SPI_HEADER_SIZE], spi_data_len_mosi);
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response_ack = true;
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} else {
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response_ack = false;
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print("SPI: CAN NACK\n");
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}
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} else {
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print("SPI: did expect data for can_write\n");
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}
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} else {
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print("SPI: unexpected endpoint"); puth(spi_endpoint); print("\n");
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}
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} else {
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// Checksum was incorrect
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response_ack = false;
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print("- incorrect data checksum ");
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puth4(spi_data_len_mosi);
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print("\n");
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hexdump(spi_buf_rx, SPI_HEADER_SIZE);
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hexdump(&(spi_buf_rx[SPI_HEADER_SIZE]), MIN(spi_data_len_mosi, 64));
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print("\n");
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}
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if (!response_ack) {
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spi_buf_tx[0] = SPI_NACK;
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next_rx_state = SPI_STATE_HEADER_NACK;
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response_len = 1U;
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} else {
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// Setup response header
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spi_buf_tx[0] = SPI_DACK;
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spi_buf_tx[1] = response_len & 0xFFU;
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spi_buf_tx[2] = (response_len >> 8) & 0xFFU;
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// Add checksum
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uint8_t checksum = SPI_CHECKSUM_START;
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for(uint16_t i = 0U; i < (response_len + 3U); i++) {
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checksum ^= spi_buf_tx[i];
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}
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spi_buf_tx[response_len + 3U] = checksum;
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response_len += 4U;
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next_rx_state = SPI_STATE_DATA_TX;
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}
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} else {
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print("SPI: RX unexpected state: "); puth(spi_state); print("\n");
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}
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// send out response
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if (response_len == 0U) {
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print("SPI: no response\n");
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spi_buf_tx[0] = SPI_NACK;
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spi_state = SPI_STATE_HEADER_NACK;
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response_len = 1U;
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}
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llspi_miso_dma(spi_buf_tx, response_len);
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spi_state = next_rx_state;
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if (!checksum_valid && (spi_checksum_error_count < __UINT16_MAX__)) {
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spi_checksum_error_count += 1U;
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}
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}
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void spi_tx_done(bool reset) {
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if ((spi_state == SPI_STATE_HEADER_NACK) || reset) {
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// Reset state
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spi_state = SPI_STATE_HEADER;
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llspi_mosi_dma(spi_buf_rx, SPI_HEADER_SIZE);
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} else if (spi_state == SPI_STATE_HEADER_ACK) {
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// ACK was sent, queue up the RX buf for the data + checksum
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spi_state = SPI_STATE_DATA_RX;
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llspi_mosi_dma(&spi_buf_rx[SPI_HEADER_SIZE], spi_data_len_mosi + 1U);
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} else if (spi_state == SPI_STATE_DATA_TX) {
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// Reset state
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spi_state = SPI_STATE_HEADER;
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llspi_mosi_dma(spi_buf_rx, SPI_HEADER_SIZE);
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} else {
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spi_state = SPI_STATE_HEADER;
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llspi_mosi_dma(spi_buf_rx, SPI_HEADER_SIZE);
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print("SPI: TX unexpected state: "); puth(spi_state); print("\n");
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}
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}
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