ref: babf901b4a508c3ec5d1f89655f10377bbdf9637
dir: /os/boot/puma/8250.c/
#include "boot.h" /* * INS8250 uart */ enum { /* * register numbers */ Data= 0, /* xmit/rcv buffer */ Iena= 1, /* interrupt enable */ Ircv= (1<<0), /* for char rcv'd */ Ixmt= (1<<1), /* for xmit buffer empty */ Irstat=(1<<2), /* for change in rcv'er status */ Imstat=(1<<3), /* for change in modem status */ Istat= 2, /* interrupt flag (read) */ Tctl= 2, /* test control (write) */ Format= 3, /* byte format */ Bits8= (3<<0), /* 8 bits/byte */ Stop2= (1<<2), /* 2 stop bits */ Pena= (1<<3), /* generate parity */ Peven= (1<<4), /* even parity */ Pforce=(1<<5), /* force parity */ Break= (1<<6), /* generate a break */ Dra= (1<<7), /* address the divisor */ Mctl= 4, /* modem control */ Dtr= (1<<0), /* data terminal ready */ Rts= (1<<1), /* request to send */ Ri= (1<<2), /* ring */ Inton= (1<<3), /* turn on interrupts */ Loop= (1<<4), /* loop back */ Lstat= 5, /* line status */ Inready=(1<<0), /* receive buffer full */ Oerror=(1<<1), /* receiver overrun */ Perror=(1<<2), /* receiver parity error */ Ferror=(1<<3), /* rcv framing error */ Outready=(1<<5), /* output buffer empty */ Mstat= 6, /* modem status */ Ctsc= (1<<0), /* clear to send changed */ Dsrc= (1<<1), /* data set ready changed */ Rire= (1<<2), /* rising edge of ring indicator */ Dcdc= (1<<3), /* data carrier detect changed */ Cts= (1<<4), /* complement of clear to send line */ Dsr= (1<<5), /* complement of data set ready line */ Ring= (1<<6), /* complement of ring indicator line */ Dcd= (1<<7), /* complement of data carrier detect line */ Scratch=7, /* scratchpad */ Dlsb= 0, /* divisor lsb */ Dmsb= 1, /* divisor msb */ Serial= 0, Modem= 1, }; typedef struct Uart Uart; struct Uart { int port; int setup; uchar sticky[8]; /* sticky write register values */ uchar txbusy; Queue *iq; Queue *oq; void (*rx)(Queue *, int); ulong frame; ulong overrun; }; Uart uart[1]; static void uartkick(void*); #define UartFREQ 1843200 #define uartwrreg(u,r,v) outb((u)->port + r, (u)->sticky[r] | (v)) #define uartrdreg(u,r) inb((u)->port + r) /* * set the baud rate by calculating and setting the baudrate * generator constant. This will work with fairly non-standard * baud rates. */ static void uartsetbaud(Uart *up, int rate) { ulong brconst; brconst = (UartFREQ+8*rate-1)/(16*rate); uartwrreg(up, Format, Dra); outb(up->port+Dmsb, (brconst>>8) & 0xff); outb(up->port+Dlsb, brconst & 0xff); uartwrreg(up, Format, 0); } /* * toggle DTR */ static void uartdtr(Uart *up, int n) { if(n) up->sticky[Mctl] |= Dtr; else up->sticky[Mctl] &= ~Dtr; uartwrreg(up, Mctl, 0); } /* * toggle RTS */ static void uartrts(Uart *up, int n) { if(n) up->sticky[Mctl] |= Rts; else up->sticky[Mctl] &= ~Rts; uartwrreg(up, Mctl, 0); } static void uartintr(Ureg*, void *arg) { Uart *up; int ch; int s, l, loops; up = arg; for(loops = 0; loops < 1024; loops++){ s = uartrdreg(up, Istat); switch(s){ case 6: /* receiver line status */ l = uartrdreg(up, Lstat); if(l & Ferror) up->frame++; if(l & Oerror) up->overrun++; break; case 4: /* received data available */ case 12: ch = inb(up->port+Data); if(up->iq) if(up->rx) (*up->rx)(up->iq, ch); else qbputc(up->iq, ch); break; case 2: /* transmitter empty */ ch = -1; if(up->oq) ch = qbgetc(up->oq); if(ch != -1) outb(up->port+Data, ch); else up->txbusy = 0; break; case 0: /* modem status */ uartrdreg(up, Mstat); break; default: if(s&1) return; print("weird modem interrupt #%2.2ux\n", s); break; } } panic("uartintr: 0x%2.2ux\n", uartrdreg(up, Istat)); } /* * turn on a port's interrupts. set DTR and RTS */ static void uartenable(Uart *up) { /* * turn on interrupts */ up->sticky[Iena] = 0; if(up->oq) up->sticky[Iena] |= Ixmt; if(up->iq) up->sticky[Iena] |= Ircv|Irstat; uartwrreg(up, Iena, 0); /* * turn on DTR and RTS */ uartdtr(up, 1); uartrts(up, 1); } void uartspecial(int port, int baud, Queue **iq, Queue **oq, void (*rx)(Queue *, int)) { Uart *up = &uart[0]; if(up->setup) return; up->setup = 1; *iq = up->iq = qopen(4*1024, 0, 0, 0); *oq = up->oq = qopen(16*1024, 0, uartkick, up); switch(port){ case 0: up->port = 0x3F8; setvec(V_COM1, uartintr, up); break; case 1: up->port = 0x2F8; setvec(V_COM2, uartintr, up); break; default: return; } /* * set rate to 9600 baud. * 8 bits/character. * 1 stop bit. * interrupts enabled. */ uartsetbaud(up, 9600); up->sticky[Format] = Bits8; uartwrreg(up, Format, 0); up->sticky[Mctl] |= Inton; uartwrreg(up, Mctl, 0x0); up->rx = rx; uartenable(up); if(baud) uartsetbaud(up, baud); } static void uartputc(int c) { Uart *up = &uart[0]; int i; for(i = 0; i < 100; i++){ if(uartrdreg(up, Lstat) & Outready) break; delay(1); } outb(up->port+Data, c); } void uartputs(char *s, int n) { Uart *up = &uart[0]; Block *b; int nl; char *p; nl = 0; for(p = s; p < s+n; p++) if(*p == '\n') nl++; b = iallocb(n+nl); while(n--){ if(*s == '\n') *b->wp++ = '\r'; *b->wp++ = *s++; } qbwrite(up->oq, b); } /* * (re)start output */ static void uartkick(void *arg) { Uart *up = arg; int x, n, c; x = splhi(); while(up->txbusy == 0 && (c = qbgetc(up->oq)) != -1) { n = 0; while((uartrdreg(up, Lstat) & Outready) == 0){ if(++n > 100000){ print("stuck serial line\n"); break; } } outb(up->port + Data, c); } splx(x); } void uartwait(void) { Uart *up = &uart[0]; while(up->txbusy) ; }