Mon 9 Dec 20:40:44 CET 2024
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@ -4,13 +4,16 @@ This software is distributed under the GNU General Public License.
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See the file LICENSE for details.
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*/
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// Derived from: https://wiki.osdev.org/Serial_Ports#Example_Code
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// For more info:
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// https://wiki.osdev.org/Serial_Ports
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// http://www.webcitation.org/5ugQv5JOw
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/* Derived from: https://wiki.osdev.org/Serial_Ports#Example_Code
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For more info:
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https://wiki.osdev.org/Serial_Ports
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http://www.webcitation.org/5ugQv5JOw
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TODO: Interrupt support; polling IO is not a good idea for carbon free air
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*/
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#include "kernel/types.h"
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#include "ioports.h"
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#include "interrupt.h"
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#include "string.h"
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#include "device.h"
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@ -33,11 +36,13 @@ See the file LICENSE for details.
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#define SERIAL_FCR 2
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#define SERIAL_FIFO_ENABLE (0x01 << 0)
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#define SERIAL_FIFO_CLEAR_RECIEVER (0x01 << 1)
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#define SERIAL_FIFO_CLEAR_RECEIVER (0x01 << 1)
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#define SERIAL_FIFO_CLEAR_TRANSMITTER (0x01 << 2)
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#define SERIAL_FIFO_DMA_MODE (0x01 << 3)
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#define SERIAL_TRIGGER_LEVEL0 (0x01 << 6)
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#define SERIAL_TRIGGER_LEVEL1 (0x01 << 7)
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#define SERIAL_TRIGGER_LEVEL0 (0x00 << 6) // 1 byte in FIFO
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#define SERIAL_TRIGGER_LEVEL1 (0x01 << 6) // 4 bytes
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#define SERIAL_TRIGGER_LEVEL2 (0x10 << 6) // 8 bytes
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#define SERIAL_TRIGGER_LEVEL3 (0x11 << 6) // 14 bytes
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#define SERIAL_LCR 3
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#define SERIAL_CHARLEN_START (0x01 << 0)
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@ -58,11 +63,21 @@ See the file LICENSE for details.
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#define SERIAL_SCRATCH 7
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// units 0,1,2,3
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static const int serial_ports[4] = { COM1, COM2, COM3, COM4 };
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static const int serial_ports_irq[4] = { 4, 3, 4, 3 };
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static void serial_init_port(int port)
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static void serial_interrupt(int i, int intr_code)
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{
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//Disable iterrupts
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printf("serial_interrupt %d %d\n",i,intr_code);
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}
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static void serial_init_port(int unit)
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{
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int port = serial_ports[unit];
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//Disable interrupts
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outb(0x00, port + SERIAL_IRQ_ENABLE);
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//Enable DLAB(set baud rate divisor)
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outb(SERIAL_DLAB_ENABLE, port + SERIAL_LCR);
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@ -73,11 +88,20 @@ static void serial_init_port(int port)
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//8 bits, no parity, one stop bit
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outb(SERIAL_CHARLEN_START * 3, port + SERIAL_LCR);
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//Enable FIFO, clear them, with 14 - byte threshold
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outb(SERIAL_FIFO_ENABLE | SERIAL_FIFO_CLEAR_RECIEVER | SERIAL_FIFO_CLEAR_TRANSMITTER | SERIAL_TRIGGER_LEVEL0 | SERIAL_TRIGGER_LEVEL1, port + SERIAL_FCR);
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outb(SERIAL_FIFO_ENABLE | SERIAL_FIFO_CLEAR_RECEIVER | SERIAL_FIFO_CLEAR_TRANSMITTER | SERIAL_TRIGGER_LEVEL0 , port + SERIAL_FCR);
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//IRQs enabled, RTS / DSR set
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outb(SERIAL_DATA_TERMINAL_READY | SERIAL_REQUEST_TO_SEND | SERIAL_AUX_OUT2, port + SERIAL_MCR);
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// setup interrupt support
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interrupt_register(serial_ports_irq[unit], serial_interrupt);
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interrupt_enable(serial_ports_irq[unit]);
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// + received data available
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outb(0x01, port + SERIAL_IRQ_ENABLE);
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printf("[COM%d] serial_init_port %x: ready.\n",unit,port);
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}
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static int serial_received(int port)
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{
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return inb(port + SERIAL_LSR) & SERIAL_DATA_AVAILABLE;
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@ -93,12 +117,23 @@ static int is_valid_port(uint8_t port_no)
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return port_no < sizeof(serial_ports) / sizeof(int);
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}
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char serial_read(uint8_t port_no)
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int serial_read(uint8_t port_no)
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{
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if(!is_valid_port(port_no))
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return -1;
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while(serial_received(serial_ports[port_no]) == 0);
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printf("[COM%d]\n",port_no);
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return inb(serial_ports[port_no]);
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}
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int serial_read_nonblock(uint8_t port_no)
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{
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if(!is_valid_port(port_no))
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return -1;
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if (serial_received(serial_ports[port_no]) == 0) return -1;
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printf("[COM%d]\n",port_no);
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return inb(serial_ports[port_no]);
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}
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@ -115,7 +150,9 @@ int serial_write(uint8_t port_no, char a)
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int serial_device_probe( int unit, int *blocksize, int *nblocks, char *info )
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{
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if(unit<0 || unit>3) return 0;
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serial_init_port(serial_ports[unit]);
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// TODO probing for real hardware
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// reinit, second time (first time in serial_init, but needed to register the device)
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serial_init_port(unit);
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*blocksize = 1;
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*nblocks = 0;
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strcpy(info,"serial");
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@ -124,10 +161,24 @@ int serial_device_probe( int unit, int *blocksize, int *nblocks, char *info )
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int serial_device_read( int unit, void *data, int length, int offset )
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{
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int i;
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int i,byte;
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char *cdata = data;
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for(i=0;i<length;i++) {
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cdata[i] = serial_read(unit);
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byte = serial_read(unit);
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if (byte==-1) break;
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cdata[i] = (char)byte;
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}
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return length;
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}
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int serial_device_read_nonblock( int unit, void *data, int length, int offset )
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{
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int i,byte;
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char *cdata = data;
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for(i=0;i<length;i++) {
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byte = serial_read_nonblock(unit);
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if (byte==-1) break;
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cdata[i] = (char)byte;
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}
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return length;
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}
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@ -142,11 +193,12 @@ int serial_device_write( int unit, const void *data, int length, int offset )
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return length;
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}
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static struct device_driver serial_driver = {
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.name = "serial",
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.probe = serial_device_probe,
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.read = serial_device_read,
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.read_nonblock = serial_device_read,
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.read_nonblock = serial_device_read_nonblock,
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.write = serial_device_write
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};
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@ -154,7 +206,7 @@ void serial_init()
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{
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int i;
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for(i = 0; i < sizeof(serial_ports) / sizeof(int); i++) {
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serial_init_port(serial_ports[i]);
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serial_init_port(i);
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}
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device_driver_register(&serial_driver);
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}
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