#include "u.h"#include "../port/lib.h"#include "mem.h"#include "dat.h"#include "fns.h"#include "io.h"#include "../port/error.h"#include "../port/uart.h" extern PhysUart i8250physuart;extern PhysUart isaphysuart;extern void* i8250alloc(int, int, int); static Uart*uartisa(int ctlrno, ISAConf* isa){	int io;	void *ctlr;	Uart *uart;	char buf[64]; 	io = isa->port;	snprint(buf, sizeof(buf), "%s%d", isaphysuart.name, ctlrno);	if(ioalloc(io, 8, 0, buf) < 0){		print("uartisa: I/O 0x%uX in use\n", io);		return nil;	} 	uart = malloc(sizeof(Uart));	ctlr = i8250alloc(io, isa->irq, BUSUNKNOWN);	if(ctlr == nil){		iofree(io);		free(uart);		return nil;	} 	uart->regs = ctlr;	snprint(buf, sizeof(buf), "COM%d", ctlrno+1);	kstrdup(&uart->name, buf);	uart->freq = isa->freq;	uart->phys = &i8250physuart; 	return uart;} static Uart*uartisapnp(void){	int ctlrno;	ISAConf isa;	Uart *head, *tail, *uart; 	/*	 * Look for up to 4 discrete UARTs on the ISA bus.	 * All suitable devices are configured to simply point	 * to the generic i8250 driver.	 */	head = tail = nil;	for(ctlrno = 2; ctlrno < 6; ctlrno++){		memset(&isa, 0, sizeof(isa));		if(!isaconfig("uart", ctlrno, &isa))			continue;		if(strcmp(isa.type, "isa") != 0)			continue;		if(isa.port == 0 || isa.irq == 0)			continue;		if(isa.freq == 0)			isa.freq = 1843200;		uart = uartisa(ctlrno, &isa);		if(uart == nil)			continue;		if(head != nil)			tail->next = uart;		else			head = uart;		tail = uart;	} 	return head;} PhysUart isaphysuart = {	.name		= "UartISA",	.pnp		= uartisapnp,	.enable		= nil,	.disable	= nil,	.kick		= nil,	.dobreak	= nil,	.baud		= nil,	.bits		= nil,	.stop		= nil,	.parity		= nil,	.modemctl	= nil,	.rts		= nil,	.dtr		= nil,	.status		= nil,	.fifo		= nil,};