static void red_stack_spi_handle_reset(void) {
int slave;
stack_announce_disconnect(&_red_stack.base);
_red_stack.base.recipients.count = 0;
log_info("Starting reinitialization of SPI slaves");
// Someone pressed reset we have to wait until he stops pressing
while (gpio_input(_red_stack_reset_stack_pin) == 0) {
// Wait 100us and check again. We wait as long as the user presses the button
SLEEP_NS(0, 1000*100);
}
SLEEP_NS(1, 1000*1000*500); // Wait 1.5s so slaves can start properly
// Reinitialize slaves
_red_stack.slave_num = 0;
for (slave = 0; slave < RED_STACK_SPI_MAX_SLAVES; slave++) {
_red_stack.slaves[slave].stack_address = slave;
_red_stack.slaves[slave].status = RED_STACK_SLAVE_STATUS_ABSENT;
_red_stack.slaves[slave].sequence_number_master = 1;
_red_stack.slaves[slave].sequence_number_slave = 0;
_red_stack.slaves[slave].next_packet_empty = false;
// Unfortunately we have to discard all of the queued packets.
// we can't be sure that the packets are for the correct slave after a reset.
while (queue_peek(&_red_stack.slaves[slave].packet_to_spi_queue) != NULL) {
queue_pop(&_red_stack.slaves[slave].packet_to_spi_queue, NULL);
}
}
}
// Resets stack
static void red_stack_reset(void) {
// Change mux of reset pin to output
gpio_mux_configure(_red_stack_reset_stack_pin, GPIO_MUX_OUTPUT);
gpio_output_clear(_red_stack_reset_stack_pin);
SLEEP_NS(0, 1000*1000*100); // Clear reset pin for 100ms to force reset
gpio_output_set(_red_stack_reset_stack_pin);
SLEEP_NS(1, 1000*1000*500); // Wait 1.5s so slaves can start properly
// Change mux back to interrupt, so we can see if a human presses reset
gpio_mux_configure(_red_stack_reset_stack_pin, GPIO_MUX_6);
}
void calibrate(void) {
uint32_t value = 0;
for(uint8_t i = 0; i < 200; i++) {
value += BA->adc_channel_get_data(BS->adc_channel);
SLEEP_NS(100);
}
BC->offset = ADC_MAX_VALUE/2 - value/200;
BA->bricklet_select(BS->port - 'a');
BA->i2c_eeprom_master_write(BA->twid->pTwi,
EEPROM_POSITION,
(char *)&BC->offset,
2);
BA->bricklet_deselect(BS->port - 'a');
}
void i2c_sleep_halfclock(void) {
SLEEP_NS(I2C_HALF_CLOCK_100KHZ);
}
// Main SPI loop. This runs independently from the brickd event thread.
// Data between RED Brick and SPI slave is exchanged every 500us.
// If there is no data to be send, we cycle through the slaves and request
// data. If there is data to be send the slave that ought to receive
// the data gets priority. This can greatly reduce latency in a big stack.
static void red_stack_spi_thread(void *opaque) {
REDStackPacket *packet_to_spi = NULL;
uint8_t stack_address_cycle;
int ret;
(void)opaque;
do {
stack_address_cycle = 0;
_red_stack_reset_detected = 0;
_red_stack.slave_num = 0;
red_stack_spi_create_routing_table();
_red_stack_spi_thread_running = false;
if (_red_stack.slave_num > 0) {
_red_stack_spi_thread_running = true;
}
// Ignore resets that we received in the meantime to prevent race conditions.
_red_stack_reset_detected = 0;
while (_red_stack_spi_thread_running) {
REDStackSlave *slave = &_red_stack.slaves[stack_address_cycle];
REDStackPacket *request = NULL;
memset(&_red_stack.packet_from_spi, 0, sizeof(Packet));
// Get packet from queue. The queue contains that are to be
// send over SPI. It is filled through from the main brickd
// event thread, so we have to make sure that there is not race
// condition.
if(slave->next_packet_empty) {
slave->next_packet_empty = false;
packet_to_spi = NULL;
} else {
mutex_lock(&(slave->packet_queue_mutex));
packet_to_spi = queue_peek(&slave->packet_to_spi_queue);
mutex_unlock(&(slave->packet_queue_mutex));
}
stack_address_cycle++;
if (stack_address_cycle >= _red_stack.slave_num) {
stack_address_cycle = 0;
}
// Set request if we have a packet to send
if (packet_to_spi != NULL) {
log_packet_debug("Packet will now be send over SPI (%s)",
packet_get_request_signature(packet_signature, &packet_to_spi->packet));
request = packet_to_spi;
}
ret = red_stack_spi_transceive_message(request, &_red_stack.packet_from_spi, slave);
if ((ret & RED_STACK_TRANSCEIVE_RESULT_MASK_SEND) == RED_STACK_TRANSCEIVE_RESULT_SEND_OK) {
if ((!((ret & RED_STACK_TRANSCEIVE_RESULT_MASK_READ) == RED_STACK_TRANSCEIVE_RESULT_READ_ERROR))) {
// If we send a packet it must have come from the queue, so we can
// pop it from the queue now.
// If the sending didn't work (for whatever reason), we don't pop it
// and therefore we will automatically try to send it again in the next cycle.
mutex_lock(&(slave->packet_queue_mutex));
queue_pop(&slave->packet_to_spi_queue, NULL);
mutex_unlock(&(slave->packet_queue_mutex));
}
}
// If we received a packet, we will dispatch it immediately.
// We have some time until we try the next SPI communication anyway.
if ((ret & RED_STACK_TRANSCEIVE_RESULT_MASK_READ) == RED_STACK_TRANSCEIVE_RESULT_READ_OK) {
// TODO: Check again if packet is valid?
// We did already check the hash.
// Before the dispatching we insert the stack position into an enumerate message
red_stack_spi_insert_position(slave);
red_stack_spi_request_dispatch_response_event();
// Wait until message is dispatched, so we don't overwrite it
// accidentally.
semaphore_acquire(&_red_stack_dispatch_packet_from_spi_semaphore);
}
SLEEP_NS(0, 1000*_red_stack_spi_poll_delay);
}
if (_red_stack.slave_num == 0) {
pthread_mutex_lock(&_red_stack_wait_for_reset_mutex);
// Use helper to be save against spurious wakeups
_red_stack_wait_for_reset_helper = 0;
while (_red_stack_wait_for_reset_helper == 0) {
pthread_cond_wait(&_red_stack_wait_for_reset_cond, &_red_stack_wait_for_reset_mutex);
}
pthread_mutex_unlock(&_red_stack_wait_for_reset_mutex);
}
if (_red_stack_reset_detected > 0) {
red_stack_spi_handle_reset();
}
} while (_red_stack_reset_detected > 0);
}
// If data should just be polled, set packet_send to NULL.
//
// If no packet is received from slave the length in packet_recv will be set to 0,
// the exact reason for that is encoded in the return value.
//
// For the return value see RED_STACK_TRANSCEIVE_RESULT_* at the top of this file.
static int red_stack_spi_transceive_message(REDStackPacket *packet_send, Packet *packet_recv, REDStackSlave *slave) {
int retval = 0;
uint8_t length, length_send;
uint8_t checksum;
int rc;
uint8_t sequence_number_master = 0xFF;
uint8_t sequence_number_slave = 0xFF;
uint8_t tx[RED_STACK_SPI_PACKET_SIZE] = {0};
uint8_t rx[RED_STACK_SPI_PACKET_SIZE] = {0};
// We assume that we don't receive anything. If we receive a packet the
// length will be overwritten again
packet_recv->header.length = 0;
// Preamble is always the same
tx[RED_STACK_SPI_PREAMBLE] = RED_STACK_SPI_PREAMBLE_VALUE;
if (packet_send == NULL) {
// If packet_send is NULL
// we send a message with empty payload (4 byte)
tx[RED_STACK_SPI_LENGTH] = RED_STACK_SPI_PACKET_EMPTY_SIZE;
retval = RED_STACK_TRANSCEIVE_RESULT_SEND_NONE;
} else if (slave->status == RED_STACK_SLAVE_STATUS_AVAILABLE) {
length = packet_send->packet.header.length;
if (length > sizeof(Packet)) {
retval |= RED_STACK_TRANSCEIVE_RESULT_SEND_ERROR;
log_error("Send length is greater then allowed (actual: %d > maximum: %d)",
length, (int)sizeof(Packet));
goto ret;
}
retval = RED_STACK_TRANSCEIVE_DATA_SEND;
tx[RED_STACK_SPI_LENGTH] = length + RED_STACK_SPI_PACKET_EMPTY_SIZE;
memcpy(tx+2, &packet_send->packet, length);
} else {
retval = RED_STACK_TRANSCEIVE_RESULT_SEND_ERROR;
log_error("Slave with stack address %d is not present in stack", slave->stack_address);
goto ret;
}
length = tx[RED_STACK_SPI_LENGTH];
// Set master and slave sequence number
tx[RED_STACK_SPI_INFO(length)] = slave->sequence_number_master | slave->sequence_number_slave;
// Calculate checksum
tx[RED_STACK_SPI_CHECKSUM(length)] = red_stack_spi_calculate_pearson_hash(tx, length-1);
struct spi_ioc_transfer spi_transfer = {
.tx_buf = (unsigned long)&tx,
.rx_buf = (unsigned long)&rx,
.len = RED_STACK_SPI_PACKET_SIZE,
};
red_stack_spi_select(slave);
rc = ioctl(_red_stack_spi_fd, SPI_IOC_MESSAGE(1), &spi_transfer);
red_stack_spi_deselect(slave);
if (rc < 0) {
// Overwrite current return status with error,
// it seems ioctl itself didn't work.
retval = RED_STACK_TRANSCEIVE_RESULT_SEND_ERROR | RED_STACK_TRANSCEIVE_RESULT_READ_ERROR;
if(packet_send == NULL) {
slave->next_packet_empty = true;
}
log_error("ioctl failed: %s (%d)", get_errno_name(errno), errno);
goto ret;
}
length_send = rc;
if (length_send != RED_STACK_SPI_PACKET_SIZE) {
// Overwrite current return status with error,
// it seems ioctl itself didn't work.
retval = RED_STACK_TRANSCEIVE_RESULT_SEND_ERROR | RED_STACK_TRANSCEIVE_RESULT_READ_ERROR;
if(packet_send == NULL) {
slave->next_packet_empty = true;
}
log_error("ioctl has unexpected result (actual: %d != expected: %d)",
length_send, RED_STACK_SPI_PACKET_SIZE);
goto ret;
}
if (rx[RED_STACK_SPI_PREAMBLE] != RED_STACK_SPI_PREAMBLE_VALUE) {
// Do not log by default, an "unproper preamble" is part of the protocol
// if the slave is too busy to fill the DMA buffers fast enough
// log_error("Received packet without proper preamble (actual: %d != expected: %d)",
// rx[RED_STACK_SPI_PREAMBLE], RED_STACK_SPI_PREAMBLE_VALUE);
retval = (retval & (~RED_STACK_TRANSCEIVE_RESULT_MASK_READ)) | RED_STACK_TRANSCEIVE_RESULT_READ_ERROR;
if(packet_send == NULL) {
slave->next_packet_empty = true;
}
goto ret;
}
// Check length
length = rx[RED_STACK_SPI_LENGTH];
if ((length != RED_STACK_SPI_PACKET_EMPTY_SIZE) &&
((length < (RED_STACK_SPI_PACKET_EMPTY_SIZE + sizeof(PacketHeader))) ||
(length > RED_STACK_SPI_PACKET_SIZE))) {
log_error("Received packet with malformed length: %d", length);
retval = (retval & (~RED_STACK_TRANSCEIVE_RESULT_MASK_READ)) | RED_STACK_TRANSCEIVE_RESULT_READ_ERROR;
if(packet_send == NULL) {
slave->next_packet_empty = true;
}
goto ret;
}
// Calculate and check checksum
checksum = red_stack_spi_calculate_pearson_hash(rx, length-1);
if (checksum != rx[RED_STACK_SPI_CHECKSUM(length)]) {
log_error("Received packet with wrong checksum (actual: %x != expected: %x)",
checksum, rx[RED_STACK_SPI_CHECKSUM(length)]);
retval = (retval & (~RED_STACK_TRANSCEIVE_RESULT_MASK_READ)) | RED_STACK_TRANSCEIVE_RESULT_READ_ERROR;
if(packet_send == NULL) {
slave->next_packet_empty = true;
}
goto ret;
}
// If we send data and the master sequence number matches to the one
// set in the packet we know that the slave received the packet!
if ((packet_send != NULL) /*&& (packet_send->status == RED_STACK_PACKET_STATUS_SEQUENCE_NUMBER_SET)*/) {
sequence_number_master = rx[RED_STACK_SPI_INFO(length)] & RED_STACK_SPI_INFO_SEQUENCE_MASTER_MASK;
if (sequence_number_master == slave->sequence_number_master) {
retval = (retval & (~RED_STACK_TRANSCEIVE_RESULT_MASK_SEND)) | RED_STACK_TRANSCEIVE_RESULT_SEND_OK;
// Increase sequence number for next packet
red_stack_increase_master_sequence_number(slave);
}
} else {
// If we didn't send anything we can always increase the sequence number,
// it doesn't matter if the slave actually received it.
red_stack_increase_master_sequence_number(slave);
}
// If the slave sequence number matches we already processed this packet
sequence_number_slave = rx[RED_STACK_SPI_INFO(length)] & RED_STACK_SPI_INFO_SEQUENCE_SLAVE_MASK;
if (sequence_number_slave == slave->sequence_number_slave) {
retval = (retval & (~RED_STACK_TRANSCEIVE_RESULT_MASK_READ)) | RED_STACK_TRANSCEIVE_RESULT_READ_NONE;
} else {
// Otherwise we save the new sequence number
slave->sequence_number_slave = sequence_number_slave;
if (length == RED_STACK_SPI_PACKET_EMPTY_SIZE) {
// Do not log by default, will produce 2000 log entries per second
// log_packet_debug("Received empty packet over SPI (w/ header)");
retval = (retval & (~RED_STACK_TRANSCEIVE_RESULT_MASK_READ)) | RED_STACK_TRANSCEIVE_RESULT_READ_NONE;
} else {
// Everything seems OK, we can copy to buffer
memcpy(packet_recv, rx+2, length - RED_STACK_SPI_PACKET_EMPTY_SIZE);
log_packet_debug("Received packet over SPI (%s)",
packet_get_response_signature(packet_signature, packet_recv));
retval = (retval & (~RED_STACK_TRANSCEIVE_RESULT_MASK_READ)) | RED_STACK_TRANSCEIVE_RESULT_READ_OK;
retval |= RED_STACK_TRANSCEIVE_DATA_RECEIVED;
}
}
ret:
return retval;
}
// Creates the "routing table", which is just the
// array of REDStackSlave structures.
static void red_stack_spi_create_routing_table(void) {
char base58[BASE58_MAX_LENGTH];
int tries, ret, i;
uint8_t stack_address = 0;
uint8_t uid_counter = 0;
log_debug("Starting to discover SPI stack slaves");
while (stack_address < RED_STACK_SPI_MAX_SLAVES) {
REDStackSlave *slave = &_red_stack.slaves[stack_address];
Packet packet;
StackEnumerateResponse *response;
REDStackPacket red_stack_packet = {
slave,
{{
0, // UID 0
sizeof(StackEnumerateRequest),
FUNCTION_STACK_ENUMERATE,
0x08, // Return expected
0
}, {0}, {0}},
RED_STACK_PACKET_STATUS_ADDED,
};
// We have to assume that the slave is available
slave->status = RED_STACK_SLAVE_STATUS_AVAILABLE;
// Send stack enumerate request
for (tries = 0; tries < RED_STACK_SPI_ROUTING_TRIES; tries++) {
ret = red_stack_spi_transceive_message(&red_stack_packet, &packet, slave);
if ((ret & RED_STACK_TRANSCEIVE_RESULT_MASK_SEND) == RED_STACK_TRANSCEIVE_RESULT_SEND_OK) {
break;
}
SLEEP_NS(0, RED_STACK_SPI_ROUTING_WAIT); // Give slave some more time
}
if (tries == RED_STACK_SPI_ROUTING_TRIES) {
// Slave does not seem to be available,
slave->status = RED_STACK_SLAVE_STATUS_ABSENT;
// This means that there can't be any more slaves above
// and we are actually done here already!
break;
}
// Receive stack enumerate response
for (tries = 0; tries < RED_STACK_SPI_ROUTING_TRIES; tries++) {
// We first check if we already received an answer before we try again
if ((ret & RED_STACK_TRANSCEIVE_RESULT_MASK_READ) == RED_STACK_TRANSCEIVE_RESULT_READ_OK) {
break;
}
// Here we sleep before transceive so that there is some time
// between the sending of stack enumerate and the receiving
// of the answer
SLEEP_NS(0, RED_STACK_SPI_ROUTING_WAIT); // Give slave some more time
ret = red_stack_spi_transceive_message(NULL, &packet, slave);
}
if (tries == RED_STACK_SPI_ROUTING_TRIES) {
// Slave does not seem to be available,
slave->status = RED_STACK_SLAVE_STATUS_ABSENT;
// This means that there can't be any more slaves above
// and we are actually done here already!
break;
}
response = (StackEnumerateResponse *)&packet;
for (i = 0; i < PACKET_MAX_STACK_ENUMERATE_UIDS; i++) {
if (response->uids[i] != 0) {
uid_counter++;
stack_add_recipient(&_red_stack.base, response->uids[i], stack_address);
log_debug("Found UID number %d of slave %d with UID %s",
i, stack_address,
base58_encode(base58, uint32_from_le(response->uids[i])));
} else {
break;
}
}
stack_address++;
}
_red_stack.slave_num = stack_address;
log_info("SPI stack slave discovery done. Found %d slave(s) with %d UID(s) in total",
stack_address, uid_counter);
}
