diff options
Diffstat (limited to 'platforms/chibios/drivers/serial_protocol.c')
| -rw-r--r-- | platforms/chibios/drivers/serial_protocol.c | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/platforms/chibios/drivers/serial_protocol.c b/platforms/chibios/drivers/serial_protocol.c new file mode 100644 index 0000000000..3e160e0c5c --- /dev/null +++ b/platforms/chibios/drivers/serial_protocol.c @@ -0,0 +1,164 @@ +// Copyright 2022 Stefan Kerkmann +// SPDX-License-Identifier: GPL-2.0-or-later + +#include <ch.h> + +#include "quantum.h" +#include "serial.h" +#include "serial_protocol.h" +#include "printf.h" +#include "synchronization_util.h" + +static inline bool initiate_transaction(uint8_t transaction_id); +static inline bool react_to_transaction(void); + +/** + * @brief This thread runs on the slave and responds to transactions initiated + * by the master. + */ +static THD_WORKING_AREA(waSlaveThread, 1024); +static THD_FUNCTION(SlaveThread, arg) { + (void)arg; + chRegSetThreadName("split_protocol_tx_rx"); + + while (true) { + split_shared_memory_lock(); + if (unlikely(!react_to_transaction())) { + /* Clear the receive queue, to start with a clean slate. + * Parts of failed transactions or spurious bytes could still be in it. */ + serial_transport_driver_clear(); + } + split_shared_memory_unlock(); + } +} + +/** + * @brief Slave specific initializations. + */ +void soft_serial_target_init(void) { + serial_transport_driver_slave_init(); + + /* Start transport thread. */ + chThdCreateStatic(waSlaveThread, sizeof(waSlaveThread), HIGHPRIO, SlaveThread, NULL); +} + +/** + * @brief Master specific initializations. + */ +void soft_serial_initiator_init(void) { + serial_transport_driver_master_init(); +} + +/** + * @brief React to transactions started by the master. + */ +static inline bool react_to_transaction(void) { + uint8_t transaction_id = 0; + /* Wait until there is a transaction for us. */ + if (unlikely(!serial_transport_receive_blocking(&transaction_id, sizeof(transaction_id)))) { + return false; + } + + /* Sanity check that we are actually responding to a valid transaction. */ + if (unlikely(transaction_id >= NUM_TOTAL_TRANSACTIONS)) { + return false; + } + + split_transaction_desc_t* transaction = &split_transaction_table[transaction_id]; + + /* Send back the handshake which is XORed as a simple checksum, + to signal that the slave is ready to receive possible transaction buffers */ + transaction_id ^= NUM_TOTAL_TRANSACTIONS; + if (unlikely(!serial_transport_send(&transaction_id, sizeof(transaction_id)))) { + return false; + } + + /* Receive transaction buffer from the master. If this transaction requires it.*/ + if (transaction->initiator2target_buffer_size) { + if (unlikely(!serial_transport_receive(split_trans_initiator2target_buffer(transaction), transaction->initiator2target_buffer_size))) { + return false; + } + } + + /* Allow any slave processing to occur. */ + if (transaction->slave_callback) { + transaction->slave_callback(transaction->initiator2target_buffer_size, split_trans_initiator2target_buffer(transaction), transaction->initiator2target_buffer_size, split_trans_target2initiator_buffer(transaction)); + } + + /* Send transaction buffer to the master. If this transaction requires it. */ + if (transaction->target2initiator_buffer_size) { + if (unlikely(!serial_transport_send(split_trans_target2initiator_buffer(transaction), transaction->target2initiator_buffer_size))) { + return false; + } + } + + return true; +} + +/** + * @brief Start transaction from the master half to the slave half. + * + * @param index Transaction Table index of the transaction to start. + * @return bool Indicates success of transaction. + */ +bool soft_serial_transaction(int index) { + split_shared_memory_lock(); + bool result = initiate_transaction((uint8_t)index); + split_shared_memory_unlock(); + + if (unlikely(!result)) { + /* Clear the receive queue, to start with a clean slate. + * Parts of failed transactions or spurious bytes could still be in it. */ + serial_transport_driver_clear(); + } + + return result; +} + +/** + * @brief Initiate transaction to slave half. + */ +static inline bool initiate_transaction(uint8_t transaction_id) { + /* Sanity check that we are actually starting a valid transaction. */ + if (unlikely(transaction_id >= NUM_TOTAL_TRANSACTIONS)) { + serial_dprintf("SPLIT: illegal transaction id\n"); + return false; + } + + split_transaction_desc_t* transaction = &split_transaction_table[transaction_id]; + + /* Send transaction table index to the slave, which doubles as basic handshake token. */ + if (unlikely(!serial_transport_send(&transaction_id, sizeof(transaction_id)))) { + serial_dprintf("SPLIT: sending handshake failed\n"); + return false; + } + + uint8_t transaction_id_shake = 0xFF; + + /* Which we always read back first so that we can error out correctly. + * - due to the half duplex limitations on return codes, we always have to read *something*. + * - without the read, write only transactions *always* succeed, even during the boot process where the slave is not ready. + */ + if (unlikely(!serial_transport_receive(&transaction_id_shake, sizeof(transaction_id_shake)) || (transaction_id_shake != (transaction_id ^ NUM_TOTAL_TRANSACTIONS)))) { + serial_dprintf("SPLIT: receiving handshake failed\n"); + return false; + } + + /* Send transaction buffer to the slave. If this transaction requires it. */ + if (transaction->initiator2target_buffer_size) { + if (unlikely(!serial_transport_send(split_trans_initiator2target_buffer(transaction), transaction->initiator2target_buffer_size))) { + serial_dprintf("SPLIT: sending buffer failed\n"); + return false; + } + } + + /* Receive transaction buffer from the slave. If this transaction requires it. */ + if (transaction->target2initiator_buffer_size) { + if (unlikely(!serial_transport_receive(split_trans_target2initiator_buffer(transaction), transaction->target2initiator_buffer_size))) { + serial_dprintf("SPLIT: receiving buffer failed\n"); + return false; + } + } + + return true; +} |