memdump/serial.c

   1 #include "mystuff.h"
   2 #include "ymsend.h"
   3 #include "io.h"
   4
   5 enum {
   6   THR = 0,
   7   RBR = 0,
   8   DLL = 0,
   9   DLM = 1,
  10   IER = 1,
  11   IIR = 2,
  12   FCR = 2,
  13   LCR = 3,
  14   MCR = 4,
  15   LSR = 5,
  16   MSR = 6,
  17   SCR = 7,
  18 };
  19
  20 int serial_init(struct serial_if *sif)
  21 {
  22   uint16_t port = sif->port;
  23   uint8_t dll, dlm, lcr;
  24
  25   /* Set 115200n81 */
  26   outb(0x83, port+LCR);
  27   outb(0x01, port+DLL);
  28   outb(0x00, port+DLM);
  29   (void)inb(port+IER);          /* Synchronize */
  30   dll = inb(port+DLL);
  31   dlm = inb(port+DLM);
  32   lcr = inb(port+LCR);
  33   outb(0x03, port+LCR);
  34   (void)inb(port+IER);          /* Synchronize */
  35
  36   if (dll != 0x01 || dlm != 0x00 || lcr != 0x83)
  37     return -1;                  /* This doesn't look like a serial port */
  38
  39   /* Disable interrupts */
  40   outb(port+IER, 0);
  41
  42   /* Enable 16550A FIFOs if available */
  43   outb(port+FCR, 0x01);         /* Enable FIFO */
  44   (void)inb(port+IER);          /* Synchronize */
  45   if (inb(port+IIR) < 0xc0)
  46     outb(port+FCR, 0x00);       /* Disable FIFOs if non-functional */
  47   (void)inb(port+IER);          /* Synchronize */
  48
  49   return 0;
  50 }
  51
  52 void serial_write(struct serial_if *sif, const void *data, size_t n)
  53 {
  54   uint16_t port = sif->port;
  55   const char *p = data;
  56   uint8_t lsr;
  57
  58   while (n--) {
  59     do {
  60       lsr = inb(port+LSR);
  61     } while (!(lsr & 0x20));
  62
  63     outb(*p++, port+THR);
  64   }
  65 }
  66
  67 void serial_read(struct serial_if *sif, void *data, size_t n)
  68 {
  69   uint16_t port = sif->port;
  70   char *p = data;
  71   uint8_t lsr;
  72
  73   while (n--) {
  74     do {
  75       lsr = inb(port+LSR);
  76     } while (!(lsr & 0x01));
  77
  78     *p++ = inb(port+RBR);
  79   }
  80 }