com32/libupload/serial.c

   1 #include <stdbool.h>
   2 #include <stdlib.h>
   3 #include <stdio.h>
   4 #include <console.h>
   5 #include <sys/io.h>
   6 #include <sys/cpu.h>
   7 #include <syslinux/config.h>
   8
   9 #include "serial.h"
  10
  11 enum {
  12     THR = 0,
  13     RBR = 0,
  14     DLL = 0,
  15     DLM = 1,
  16     IER = 1,
  17     IIR = 2,
  18     FCR = 2,
  19     LCR = 3,
  20     MCR = 4,
  21     LSR = 5,
  22     MSR = 6,
  23     SCR = 7,
  24 };
  25
  26
  27 int serial_init(struct serial_if *sif, const char *argv[])
  28 {
  29     const struct syslinux_serial_console_info *sci
  30         = syslinux_serial_console_info();
  31     uint16_t port;
  32     unsigned int divisor;
  33     uint8_t dll, dlm, lcr;
  34
  35     if (!argv[0]) {
  36         if (sci->iobase) {
  37             port = sci->iobase;
  38         } else {
  39             printf("No port number specified and not using serial console!\n");
  40             return -1;
  41         }
  42     } else {
  43         port = strtoul(argv[0], NULL, 0);
  44         if (port <= 3) {
  45             uint16_t addr = ((uint16_t *)0x400)[port];
  46             if (!addr) {
  47                 printf("No serial port address found!\n");
  48             return -1;
  49             }
  50             printf("Serial port %u is at 0x%04x\n", port, addr);
  51             port = addr;
  52         }
  53     }
  54
  55     sif->port = port;
  56     sif->console = false;
  57
  58     divisor = 1;                /* Default speed = 115200 bps */
  59
  60     /* Check to see if this is the same as the serial console */
  61     if (port == sci->iobase) {
  62         /* Overlaying the console... */
  63         sif->console = true;
  64
  65         /* Default to already configured speed */
  66         divisor = sci->divisor;
  67
  68         /* Shut down I/O to the console for the time being */
  69         openconsole(&dev_null_r, &dev_null_w);
  70     }
  71
  72     if (argv[0] && argv[1])
  73         divisor = 115200/strtoul(argv[1], NULL, 0);
  74
  75     cli();                      /* Just in case... */
  76
  77     /* Save old register settings */
  78     sif->old.lcr = inb(port + LCR);
  79     sif->old.mcr = inb(port + MCR);
  80     sif->old.iir = inb(port + IIR);
  81
  82     /* Set speed */
  83     outb(0x83, port + LCR);     /* Enable divisor access */
  84     sif->old.dll = inb(port + DLL);
  85     sif->old.dlm = inb(port + DLM);
  86     outb(divisor, port + DLL);
  87     outb(divisor >> 8, port + DLM);
  88     (void)inb(port + IER);      /* Synchronize */
  89
  90     dll = inb(port + DLL);
  91     dlm = inb(port + DLM);
  92     lcr = inb(port + LCR);
  93     outb(0x03, port + LCR);     /* Enable data access, n81 */
  94     (void)inb(port + IER);      /* Synchronize */
  95     sif->old.ier = inb(port + IER);
  96
  97     /* Disable interrupts */
  98     outb(0, port + IER);
  99
 100     sti();
 101
 102     if (dll != (uint8_t)divisor ||
 103         dlm != (uint8_t)(divisor >> 8) ||
 104         lcr != 0x83) {
 105         serial_cleanup(sif);
 106         printf("No serial port detected!\n");
 107         return -1;              /* This doesn't look like a serial port */
 108     }
 109
 110     /* Enable 16550A FIFOs if available */
 111     outb(0x01, port + FCR);     /* Enable FIFO */
 112     (void)inb(port + IER);      /* Synchronize */
 113     if (inb(port + IIR) < 0xc0)
 114         outb(0x00, port + FCR); /* Disable FIFOs if non-functional */
 115     (void)inb(port + IER);      /* Synchronize */
 116
 117     return 0;
 118 }
 119
 120 void serial_write(struct serial_if *sif, const void *data, size_t n)
 121 {
 122     uint16_t port = sif->port;
 123     const char *p = data;
 124     uint8_t lsr;
 125
 126     while (n--) {
 127         do {
 128             lsr = inb(port + LSR);
 129         } while (!(lsr & 0x20));
 130
 131         outb(*p++, port + THR);
 132     }
 133 }
 134
 135 void serial_read(struct serial_if *sif, void *data, size_t n)
 136 {
 137     uint16_t port = sif->port;
 138     char *p = data;
 139     uint8_t lsr;
 140
 141     while (n--) {
 142         do {
 143             lsr = inb(port + LSR);
 144         } while (!(lsr & 0x01));
 145
 146         *p++ = inb(port + RBR);
 147     }
 148 }
 149
 150 void serial_cleanup(struct serial_if *sif)
 151 {
 152     uint16_t port = sif->port;
 153
 154     outb(0x83, port + LCR);
 155     (void)inb(port + IER);
 156     outb(sif->old.dll, port + DLL);
 157     outb(sif->old.dlm, port + DLM);
 158     (void)inb(port + IER);
 159     outb(sif->old.lcr & 0x7f, port + LCR);
 160     (void)inb(port + IER);
 161     outb(sif->old.mcr, port + MCR);
 162     outb(sif->old.ier, port + IER);
 163     if (sif->old.iir < 0xc0)
 164         outb(0x00, port + FCR); /* Disable FIFOs */
 165
 166     /* Re-enable console messages, if we shut them down */
 167     if (sif->console)
 168         openconsole(&dev_null_r, &dev_stdcon_w);
 169 }