sys/src/9/pc/uartisa.c

   1 #include "u.h"
   2 #include "../port/lib.h"
   3 #include "mem.h"
   4 #include "dat.h"
   5 #include "fns.h"
   6 #include "io.h"
   7 #include "../port/error.h"
   8
   9 extern PhysUart i8250physuart;
  10 extern PhysUart isaphysuart;
  11 extern void* i8250alloc(int, int, int);
  12
  13 static Uart*
  14 uartisa(int ctlrno, ISAConf* isa)
  15 {
  16         int io;
  17         void *ctlr;
  18         Uart *uart;
  19         char buf[64];
  20
  21         io = isa->port;
  22         snprint(buf, sizeof(buf), "%s%d", isaphysuart.name, ctlrno);
  23         if(ioalloc(io, 8, 0, buf) < 0){
  24                 print("uartisa: I/O 0x%uX in use\n", io);
  25                 return nil;
  26         }
  27
  28         uart = malloc(sizeof(Uart));
  29         ctlr = i8250alloc(io, isa->irq, BUSUNKNOWN);
  30         if(uart == nil || ctlr == nil){
  31                 iofree(io);
  32                 free(uart);
  33                 return nil;
  34         }
  35
  36         uart->regs = ctlr;
  37         snprint(buf, sizeof(buf), "COM%d", ctlrno+1);
  38         kstrdup(&uart->name, buf);
  39         uart->freq = isa->freq;
  40         uart->phys = &i8250physuart;
  41
  42         return uart;
  43 }
  44
  45 static Uart*
  46 uartisapnp(void)
  47 {
  48         int ctlrno;
  49         ISAConf isa;
  50         Uart *head, *tail, *uart;
  51
  52         /*
  53          * Look for up to 4 discrete UARTs on the ISA bus.
  54          * All suitable devices are configured to simply point
  55          * to the generic i8250 driver.
  56          */
  57         head = tail = nil;
  58         for(ctlrno = 2; ctlrno < 6; ctlrno++){
  59                 memset(&isa, 0, sizeof(isa));
  60                 if(!isaconfig("uart", ctlrno, &isa))
  61                         continue;
  62                 if(strcmp(isa.type, "isa") != 0)
  63                         continue;
  64                 if(isa.port == 0 || isa.irq == 0)
  65                         continue;
  66                 if(isa.freq == 0)
  67                         isa.freq = 1843200;
  68                 uart = uartisa(ctlrno, &isa);
  69                 if(uart == nil)
  70                         continue;
  71                 if(head != nil)
  72                         tail->next = uart;
  73                 else
  74                         head = uart;
  75                 tail = uart;
  76         }
  77
  78         return head;
  79 }
  80
  81 PhysUart isaphysuart = {
  82         .name           = "UartISA",
  83         .pnp            = uartisapnp,
  84         .enable         = nil,
  85         .disable        = nil,
  86         .kick           = nil,
  87         .dobreak        = nil,
  88         .baud           = nil,
  89         .bits           = nil,
  90         .stop           = nil,
  91         .parity         = nil,
  92         .modemctl       = nil,
  93         .rts            = nil,
  94         .dtr            = nil,
  95         .status         = nil,
  96         .fifo           = nil,
  97 };