arch/ppc/boot/common/ns16550.c

   1 /*
   2  * COM1 NS16550 support
   3  */
   4
   5 #include <linux/config.h>
   6 #include <linux/types.h>
   7 #include <linux/serial.h>
   8 #include <linux/serial_reg.h>
   9 #include <asm/serial.h>
  10
  11 #include "nonstdio.h"
  12 #include "serial.h"
  13
  14 #define SERIAL_BAUD     9600
  15
  16 extern unsigned long ISA_io;
  17
  18 static struct serial_state rs_table[RS_TABLE_SIZE] = {
  19         SERIAL_PORT_DFNS        /* Defined in <asm/serial.h> */
  20 };
  21
  22 static int shift;
  23
  24 unsigned long serial_init(int chan, void *ignored)
  25 {
  26         unsigned long com_port;
  27         unsigned char lcr, dlm;
  28
  29         /* We need to find out which type io we're expecting.  If it's
  30          * 'SERIAL_IO_PORT', we get an offset from the isa_io_base.
  31          * If it's 'SERIAL_IO_MEM', we can the exact location.  -- Tom */
  32         switch (rs_table[chan].io_type) {
  33                 case SERIAL_IO_PORT:
  34                         com_port = rs_table[chan].port;
  35                         break;
  36                 case SERIAL_IO_MEM:
  37                         com_port = (unsigned long)rs_table[chan].iomem_base;
  38                         break;
  39                 default:
  40                         /* We can't deal with it. */
  41                         return -1;
  42         }
  43
  44         /* How far apart the registers are. */
  45         shift = rs_table[chan].iomem_reg_shift;
  46
  47         /* save the LCR */
  48         lcr = inb(com_port + (UART_LCR << shift));
  49         /* Access baud rate */
  50         outb(com_port + (UART_LCR << shift), 0x80);
  51         dlm = inb(com_port + (UART_DLM << shift));
  52         /*
  53          * Test if serial port is unconfigured.
  54          * We assume that no-one uses less than 110 baud or
  55          * less than 7 bits per character these days.
  56          *  -- paulus.
  57          */
  58
  59         if ((dlm <= 4) && (lcr & 2))
  60                 /* port is configured, put the old LCR back */
  61                 outb(com_port + (UART_LCR << shift), lcr);
  62         else {
  63                 /* Input clock. */
  64                 outb(com_port + (UART_DLL << shift),
  65                      (BASE_BAUD / SERIAL_BAUD) & 0xFF);
  66                 outb(com_port + (UART_DLM << shift),
  67                      (BASE_BAUD / SERIAL_BAUD) >> 8);
  68                 /* 8 data, 1 stop, no parity */
  69                 outb(com_port + (UART_LCR << shift), 0x03);
  70                 /* RTS/DTR */
  71                 outb(com_port + (UART_MCR << shift), 0x03);
  72         }
  73         /* Clear & enable FIFOs */
  74         outb(com_port + (UART_FCR << shift), 0x07);
  75
  76         return (com_port);
  77 }
  78
  79 void
  80 serial_putc(unsigned long com_port, unsigned char c)
  81 {
  82         while ((inb(com_port + (UART_LSR << shift)) & UART_LSR_THRE) == 0)
  83                 ;
  84         outb(com_port, c);
  85 }
  86
  87 unsigned char
  88 serial_getc(unsigned long com_port)
  89 {
  90         while ((inb(com_port + (UART_LSR << shift)) & UART_LSR_DR) == 0)
  91                 ;
  92         return inb(com_port);
  93 }
  94
  95 int
  96 serial_tstc(unsigned long com_port)
  97 {
  98         return ((inb(com_port + (UART_LSR << shift)) & UART_LSR_DR) != 0);
  99 }