arch/ppc64/kernel/udbg_16550.c

   1 /*
   2  * udbg for for NS16550 compatable serial ports
   3  *
   4  * Copyright (C) 2001-2005 PPC 64 Team, IBM Corp
   5  *
   6  *      This program is free software; you can redistribute it and/or
   7  *      modify it under the terms of the GNU General Public License
   8  *      as published by the Free Software Foundation; either version
   9  *      2 of the License, or (at your option) any later version.
  10  */
  11 #include <linux/config.h>
  12 #include <linux/types.h>
  13 #include <asm/udbg.h>
  14 #include <asm/io.h>
  15
  16 extern u8 real_readb(volatile u8 __iomem  *addr);
  17 extern void real_writeb(u8 data, volatile u8 __iomem *addr);
  18
  19 struct NS16550 {
  20         /* this struct must be packed */
  21         unsigned char rbr;  /* 0 */
  22         unsigned char ier;  /* 1 */
  23         unsigned char fcr;  /* 2 */
  24         unsigned char lcr;  /* 3 */
  25         unsigned char mcr;  /* 4 */
  26         unsigned char lsr;  /* 5 */
  27         unsigned char msr;  /* 6 */
  28         unsigned char scr;  /* 7 */
  29 };
  30
  31 #define thr rbr
  32 #define iir fcr
  33 #define dll rbr
  34 #define dlm ier
  35 #define dlab lcr
  36
  37 #define LSR_DR   0x01  /* Data ready */
  38 #define LSR_OE   0x02  /* Overrun */
  39 #define LSR_PE   0x04  /* Parity error */
  40 #define LSR_FE   0x08  /* Framing error */
  41 #define LSR_BI   0x10  /* Break */
  42 #define LSR_THRE 0x20  /* Xmit holding register empty */
  43 #define LSR_TEMT 0x40  /* Xmitter empty */
  44 #define LSR_ERR  0x80  /* Error */
  45
  46 static volatile struct NS16550 __iomem *udbg_comport;
  47
  48 static void udbg_550_putc(unsigned char c)
  49 {
  50         if (udbg_comport) {
  51                 while ((in_8(&udbg_comport->lsr) & LSR_THRE) == 0)
  52                         /* wait for idle */;
  53                 out_8(&udbg_comport->thr, c);
  54                 if (c == '\n')
  55                         udbg_550_putc('\r');
  56         }
  57 }
  58
  59 static int udbg_550_getc_poll(void)
  60 {
  61         if (udbg_comport) {
  62                 if ((in_8(&udbg_comport->lsr) & LSR_DR) != 0)
  63                         return in_8(&udbg_comport->rbr);
  64                 else
  65                         return -1;
  66         }
  67         return -1;
  68 }
  69
  70 static unsigned char udbg_550_getc(void)
  71 {
  72         if (udbg_comport) {
  73                 while ((in_8(&udbg_comport->lsr) & LSR_DR) == 0)
  74                         /* wait for char */;
  75                 return in_8(&udbg_comport->rbr);
  76         }
  77         return 0;
  78 }
  79
  80 void udbg_init_uart(void __iomem *comport, unsigned int speed)
  81 {
  82         u16 dll = speed ? (115200 / speed) : 12;
  83
  84         if (comport) {
  85                 udbg_comport = (struct NS16550 __iomem *)comport;
  86                 out_8(&udbg_comport->lcr, 0x00);
  87                 out_8(&udbg_comport->ier, 0xff);
  88                 out_8(&udbg_comport->ier, 0x00);
  89                 out_8(&udbg_comport->lcr, 0x80);        /* Access baud rate */
  90                 out_8(&udbg_comport->dll, dll & 0xff);  /* 1 = 115200,  2 = 57600,
  91                                                            3 = 38400, 12 = 9600 baud */
  92                 out_8(&udbg_comport->dlm, dll >> 8);    /* dll >> 8 which should be zero
  93                                                            for fast rates; */
  94                 out_8(&udbg_comport->lcr, 0x03);        /* 8 data, 1 stop, no parity */
  95                 out_8(&udbg_comport->mcr, 0x03);        /* RTS/DTR */
  96                 out_8(&udbg_comport->fcr ,0x07);        /* Clear & enable FIFOs */
  97                 udbg_putc = udbg_550_putc;
  98                 udbg_getc = udbg_550_getc;
  99                 udbg_getc_poll = udbg_550_getc_poll;
 100         }
 101 }
 102
 103 #ifdef CONFIG_PPC_MAPLE
 104 void udbg_maple_real_putc(unsigned char c)
 105 {
 106         if (udbg_comport) {
 107                 while ((real_readb(&udbg_comport->lsr) & LSR_THRE) == 0)
 108                         /* wait for idle */;
 109                 real_writeb(c, &udbg_comport->thr); eieio();
 110                 if (c == '\n')
 111                         udbg_maple_real_putc('\r');
 112         }
 113 }
 114
 115 void udbg_init_maple_realmode(void)
 116 {
 117         udbg_comport = (volatile struct NS16550 __iomem *)0xf40003f8;
 118
 119         udbg_putc = udbg_maple_real_putc;
 120         udbg_getc = NULL;
 121         udbg_getc_poll = NULL;
 122 }
 123 #endif /* CONFIG_PPC_MAPLE */