VOID c_serial_handler(VOID)
{
//atomic_on();
//rtx_dbug_outs((CHAR *)"IN SERIAL current running process: ");
//rtx_dbug_out_number(get_running_process()->pid);
//rtx_dbug_outs((CHAR *)"current caller: ");
//rtx_dbug_out_number(get_running_process()->pid);
context_switch(get_uart_pcb());
process_switch_if_there_is_a_higher_priority_process();
//atomic_off();
}
void irq_handler(irq_type type) {
assert(pCurrentProcessPCB->currentState != NEW,"A new process has been interrupted.");
pCurrentProcessPCB->currentState = INTERRUPTED;
switch (type) {
case TIMER_IRQ:
context_switch(pCurrentProcessPCB, get_timer_pcb());
break;
case UART0_IRQ:
context_switch(pCurrentProcessPCB, get_uart_pcb());
break;
default:
break;
}
k_release_processor();
}
void execute_uart() {
char c;
/*
IER - Interrupt Enable Register. Contains individual interrupt enable bits for the 7 potential UART interrupts.
IIR - Interrupt ID Register. Identifies which interrupt(s) are pending.
LSR - Line Status Register. Contains flags for transmit and receive status, including line errors.
*/
// Information about the interrupt
uint8_t IIR_IntId; // Interrupt ID from IIR
// Line Status Register value
uint8_t LSR_Val; // LSR Value
uint8_t dummy = dummy; // dummy variable to clear interrupt upon LSR error
LPC_UART_TypeDef * pUart = (LPC_UART_TypeDef *)LPC_UART0;
// Reading IIR automatically acknowledges the interrupt
IIR_IntId = (pUart->IIR) >> 1 ; // skip pending bit in IIR
if (IIR_IntId & IIR_Receive_Data_Available) { // Receive Data Available
Envelope * message = 0;
int hot_key_exec = 0;
// Note: read RBR will clear the interrupt
c = pUart->RBR; // read from the uart
buffer[0] = c;
i++;
buffer[1] = 0;
hot_key_exec = do_hot_key(*buffer);
if (hot_key_exec == 0) {
/* If we have space, parse and echo the buffer contents
Sending the messages takes 2 blocks so we need at least that many
*/
if(numberOfMemoryBlocksCurrentlyAllocated < MAX_ALLOWED_MEMORY_BLOCKS -1){
message = k_request_memory_block();
message->sender_pid = get_uart_pcb()->processId;
message->receiver_pid = get_kcd_pcb()->processId;
message->message_type = KEYBOARD_INPUT;
set_message_bytes(message, buffer, 2);
k_send_message(message->receiver_pid, message);
}else{
// Otherwise just use polling since we have no choice
uart0_polling_put_string(buffer);
uart0_polling_put_string("Insufficient memory: Unable to pass message to KCD.\r\n");
}
}
} else if (IIR_IntId & IIR_THR_Empty) { // THRE Interrupt, transmit holding register empty
LSR_Val = pUart->LSR;
if(LSR_Val & LSR_THR_Empty) {
g_UART0_TX_empty = 1; // UART is ready to transmit
} else {
g_UART0_TX_empty = 0; // UART is not ready to transmit yet
}
} else if (IIR_IntId & IIR_Receive_Line_Status) {
LSR_Val = pUart->LSR;
if (LSR_Val & (LSR_OE|LSR_PE|LSR_FE|LSR_RXFE|LSR_BI) ) {
// There are errors or break interrupt
// Read LSR will clear the interrupt
dummy = pUart->RBR; //Dummy read on RX to clear interrupt, then bail out
return ; // error occurs, return
}
// If no error on RLS, normal ready, save into the data buffer.
// Note: read RBR will clear the interrupt
if (LSR_Val & LSR_Unread_Character) { // Receive Data Ready
g_UART0_buffer[g_UART0_count++] = pUart->RBR; // read from the uart
if ( g_UART0_count == BUFSIZE ) {
g_UART0_count = 0; // buffer overflow
}
}
} else { // IIR_CTI and reserved combination are not implemented yet
return;
}
}