117 lines
4.9 KiB
C
117 lines
4.9 KiB
C
//
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// Created by rick on 28-01-21.
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//
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#include <myke/drivers/serial.h>
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#include <sys/types.h>
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#include <myke/drivers/ports.h>
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#define SERIAL_INTERRUPT_DATA_AVAILABLE (1 << 0)
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#define SERIAL_INTERRUPT_TRANSMITTER_EMPTY (1 << 1)
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#define SERIAL_INTERRUPT_BREAK_ERROR (1 << 2)
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#define SERIAL_INTERRUPT_STATUS_CHANGE (1 << 3)
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#define LINE_STATUS_DATA_READY (1 << 0)
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#define LINE_STATUS_OVERRUN_ERROR (1 << 1)
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#define LINE_STATUS_PARITY_ERROR (1 << 2)
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#define LINE_STATUS_FRAMING_ERROR (1 << 3)
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#define LINE_STATUS_BREAK_INDICATOR (1 << 4)
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#define LINE_STATUS_TRANSMITTER_HOLDING_REGISTER_EMPTY (1 << 5)
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#define LINE_STATUS_TRANSMITTER_EMPTY (1 << 6)
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#define LINE_STATUS_IMPENDING_ERROR (1 << 7)
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#define LINE_CONTROL_DATA_BITS_5 (0b00)
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#define LINE_CONTROL_DATA_BITS_6 (0b01)
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#define LINE_CONTROL_DATA_BITS_7 (0b10)
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#define LINE_CONTROL_DATA_BITS_8 (0b11)
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#define LINE_CONTROL_STOP_BITS_1 (0 << 2)
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#define LINE_CONTROL_STOP_BITS_1_5_2 (1 << 2)
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#define LINE_CONTROL_PARTY_NONE (0b000 << 3)
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#define LINE_CONTROL_PARTY_ODD (0b001 << 3)
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#define LINE_CONTROL_PARTY_EVEN (0b010 << 3)
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#define LINE_CONTROL_PARTY_MARK (0b101 << 3)
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#define LINE_CONTROL_PARTY_SPACE (0b111 << 3)
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#define LINE_CONTROL_DIVISOR (1 << 7)
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#define FIFO_CONTROL_ENABLE (1 << 0)
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#define FIFO_CONTROL_CLEAR_RECEIVE (1 << 1)
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#define FIFO_CONTROL_CLEAR_TRANSMIT (1 << 2)
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#define FIFO_CONTROL_DMA_MODE_SELECT (1 << 3)
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// reserved
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#define FIFO_CONTROL_64_BYTE_ENABLE (1 << 5)
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#define FIFO_CONTROL_TRIGGER_LEVEL_1_BYTE (0b00 << 6)
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#define FIFO_CONTROL_TRIGGER_LEVEL_4_BYTE (0b01 << 6)
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#define FIFO_CONTROL_TRIGGER_LEVEL_8_BYTE (0b10 << 6)
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#define FIFO_CONTROL_TRIGGER_LEVEL_14_BYTE (0b11 << 6)
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#define MODEM_CONTROL_DATA_TERMINAL_READY (1 << 0)
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#define MODEM_CONTROL_REQUEST_TO_SEND (1 << 1)
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#define MODEM_CONTROL_AUX_OUTPUT_1 (1 << 2)
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#define MODEM_CONTROL_AUX_OUTPUT_2 (1 << 3)
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#define MODEM_CONTROL_LOOPBACK_MODE (1 << 4)
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#define MODEM_CONTROL_AUTOFLOW_CONTROL_ENABLED (1 << 5)
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int serial_init() {
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port_byte_out(PORT_SERIAL_0 + PORT_SERIAL_INTERRUPT, 0); // Disable all interrupts
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port_byte_out(PORT_SERIAL_0 + PORT_SERIAL_LINE_CONTROL,
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LINE_CONTROL_DIVISOR); // Enable DLAB (set baud rate divisor)
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port_byte_out(PORT_SERIAL_0 + PORT_SERIAL_DLAB_LSB, 0x03); // Set divisor to 3 (lo byte) 38400 baud
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port_byte_out(PORT_SERIAL_0 + PORT_SERIAL_DLAB_MSB, 0x00); // (hi byte)
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port_byte_out(PORT_SERIAL_0 + PORT_SERIAL_LINE_CONTROL,
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LINE_CONTROL_DATA_BITS_8); // 8 bits, no parity, one stop bit
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port_byte_out(PORT_SERIAL_0 + PORT_SERIAL_INTERRUPT_ID_FIFO,
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FIFO_CONTROL_ENABLE
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| FIFO_CONTROL_CLEAR_RECEIVE
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| FIFO_CONTROL_CLEAR_TRANSMIT
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| FIFO_CONTROL_TRIGGER_LEVEL_14_BYTE); // Enable FIFO, clear them, with 14-byte threshold
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port_byte_out(PORT_SERIAL_0 + PORT_SERIAL_MODEM_CONTROL,
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MODEM_CONTROL_DATA_TERMINAL_READY
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| MODEM_CONTROL_REQUEST_TO_SEND
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| MODEM_CONTROL_AUX_OUTPUT_2); // IRQs enabled, RTS/DSR set
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port_byte_out(PORT_SERIAL_0 + PORT_SERIAL_MODEM_CONTROL,
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MODEM_CONTROL_REQUEST_TO_SEND
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| MODEM_CONTROL_AUX_OUTPUT_1
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| MODEM_CONTROL_AUX_OUTPUT_2
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| MODEM_CONTROL_LOOPBACK_MODE); // Set in loopback mode, test the serial chip
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port_byte_out(PORT_SERIAL_0 + PORT_SERIAL_DATA,
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0xAE); // Test serial chip (send byte 0xAE and check if serial returns same byte)
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// Check if serial is faulty (i.e: not same byte as sent)
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if (port_byte_in(PORT_SERIAL_0 + PORT_SERIAL_DATA) != 0xAE) {
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return 1;
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}
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// If serial is not faulty set it in normal operation mode
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// (not-loopback with IRQs enabled and OUT#1 and OUT#2 bits enabled)
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port_byte_out(PORT_SERIAL_0 + PORT_SERIAL_MODEM_CONTROL,
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MODEM_CONTROL_DATA_TERMINAL_READY
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| MODEM_CONTROL_REQUEST_TO_SEND
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| MODEM_CONTROL_AUX_OUTPUT_1
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| MODEM_CONTROL_AUX_OUTPUT_2);
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return 0;
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}
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int is_transmit_empty() {
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return port_byte_in(PORT_SERIAL_0 + PORT_SERIAL_LINE_STATUS) & LINE_STATUS_TRANSMITTER_HOLDING_REGISTER_EMPTY;
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}
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void write_serial(char a) {
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while (is_transmit_empty() == 0);
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port_byte_out(PORT_SERIAL_0 + PORT_SERIAL_DATA, a);
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}
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void serial_kprint(const char *msg) {
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uint32_t i = 0;
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while (1) {
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char c = msg[i];
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if (c == 0) {
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break;
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}
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if (c == '\n') {
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write_serial('\r');
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}
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write_serial(c);
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i++;
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}
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} |