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 #if defined(CONFIG_XILINX_VIRTEX)
  12 #include <platforms/4xx/xparameters/xparameters.h>
  13 #endif
  14 #include "nonstdio.h"
  15 #include "serial.h"
  16
  17 #define SERIAL_BAUD     9600
  18
  19 extern unsigned long ISA_io;
  20
  21 static struct serial_state rs_table[RS_TABLE_SIZE] = {
  22         SERIAL_PORT_DFNS        /* Defined in <asm/serial.h> */
  23 };
  24
  25 static int shift;
  26
  27 unsigned long serial_init(int chan, void *ignored)
  28 {
  29         unsigned long com_port, base_baud;
  30         unsigned char lcr, dlm;
  31
  32         /* We need to find out which type io we're expecting.  If it's
  33          * 'SERIAL_IO_PORT', we get an offset from the isa_io_base.
  34          * If it's 'SERIAL_IO_MEM', we can the exact location.  -- Tom */
  35         switch (rs_table[chan].io_type) {
  36                 case SERIAL_IO_PORT:
  37                         com_port = rs_table[chan].port;
  38                         break;
  39                 case SERIAL_IO_MEM:
  40                         com_port = (unsigned long)rs_table[chan].iomem_base;
  41                         break;
  42                 default:
  43                         /* We can't deal with it. */
  44                         return -1;
  45         }
  46
  47         /* How far apart the registers are. */
  48         shift = rs_table[chan].iomem_reg_shift;
  49         /* Base baud.. */
  50         base_baud = rs_table[chan].baud_base;
  51
  52         /* save the LCR */
  53         lcr = inb(com_port + (UART_LCR << shift));
  54         /* Access baud rate */
  55         outb(com_port + (UART_LCR << shift), 0x80);
  56         dlm = inb(com_port + (UART_DLM << shift));
  57         /*
  58          * Test if serial port is unconfigured.
  59          * We assume that no-one uses less than 110 baud or
  60          * less than 7 bits per character these days.
  61          *  -- paulus.
  62          */
  63
  64         if ((dlm <= 4) && (lcr & 2))
  65                 /* port is configured, put the old LCR back */
  66                 outb(com_port + (UART_LCR << shift), lcr);
  67         else {
  68                 /* Input clock. */
  69                 outb(com_port + (UART_DLL << shift),
  70                      (base_baud / SERIAL_BAUD) & 0xFF);
  71                 outb(com_port + (UART_DLM << shift),
  72                      (base_baud / SERIAL_BAUD) >> 8);
  73                 /* 8 data, 1 stop, no parity */
  74                 outb(com_port + (UART_LCR << shift), 0x03);
  75                 /* RTS/DTR */
  76                 outb(com_port + (UART_MCR << shift), 0x03);
  77         }
  78         /* Clear & enable FIFOs */
  79         outb(com_port + (UART_FCR << shift), 0x07);
  80
  81         return (com_port);
  82 }
  83
  84 void
  85 serial_putc(unsigned long com_port, unsigned char c)
  86 {
  87         while ((inb(com_port + (UART_LSR << shift)) & UART_LSR_THRE) == 0)
  88                 ;
  89         outb(com_port, c);
  90 }
  91
  92 unsigned char
  93 serial_getc(unsigned long com_port)
  94 {
  95         while ((inb(com_port + (UART_LSR << shift)) & UART_LSR_DR) == 0)
  96                 ;
  97         return inb(com_port);
  98 }
  99
 100 int
 101 serial_tstc(unsigned long com_port)
 102 {
 103         return ((inb(com_port + (UART_LSR << shift)) & UART_LSR_DR) != 0);
 104 }