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/ppcdebug.h>
  14 #include <asm/processor.h>
  15 #include <asm/naca.h>
  16 #include <asm/uaccess.h>
  17 #include <asm/machdep.h>
  18 #include <asm/io.h>
  19 #include <asm/prom.h>
  20
  21 extern u8 real_readb(volatile u8 __iomem  *addr);
  22 extern void real_writeb(u8 data, volatile u8 __iomem *addr);
  23
  24 struct NS16550 {
  25         /* this struct must be packed */
  26         unsigned char rbr;  /* 0 */
  27         unsigned char ier;  /* 1 */
  28         unsigned char fcr;  /* 2 */
  29         unsigned char lcr;  /* 3 */
  30         unsigned char mcr;  /* 4 */
  31         unsigned char lsr;  /* 5 */
  32         unsigned char msr;  /* 6 */
  33         unsigned char scr;  /* 7 */
  34 };
  35
  36 #define thr rbr
  37 #define iir fcr
  38 #define dll rbr
  39 #define dlm ier
  40 #define dlab lcr
  41
  42 #define LSR_DR   0x01  /* Data ready */
  43 #define LSR_OE   0x02  /* Overrun */
  44 #define LSR_PE   0x04  /* Parity error */
  45 #define LSR_FE   0x08  /* Framing error */
  46 #define LSR_BI   0x10  /* Break */
  47 #define LSR_THRE 0x20  /* Xmit holding register empty */
  48 #define LSR_TEMT 0x40  /* Xmitter empty */
  49 #define LSR_ERR  0x80  /* Error */
  50
  51 static volatile struct NS16550 __iomem *udbg_comport;
  52
  53 static void udbg_550_putc(unsigned char c)
  54 {
  55         if (udbg_comport) {
  56                 while ((in_8(&udbg_comport->lsr) & LSR_THRE) == 0)
  57                         /* wait for idle */;
  58                 out_8(&udbg_comport->thr, c);
  59                 if (c == '\n')
  60                         udbg_550_putc('\r');
  61         }
  62 }
  63
  64 static int udbg_550_getc_poll(void)
  65 {
  66         if (udbg_comport) {
  67                 if ((in_8(&udbg_comport->lsr) & LSR_DR) != 0)
  68                         return in_8(&udbg_comport->rbr);
  69                 else
  70                         return -1;
  71         }
  72         return -1;
  73 }
  74
  75 static unsigned char udbg_550_getc(void)
  76 {
  77         if (udbg_comport) {
  78                 while ((in_8(&udbg_comport->lsr) & LSR_DR) == 0)
  79                         /* wait for char */;
  80                 return in_8(&udbg_comport->rbr);
  81         }
  82         return 0;
  83 }
  84
  85 void udbg_init_uart(void __iomem *comport, unsigned int speed)
  86 {
  87         u16 dll = speed ? (115200 / speed) : 12;
  88
  89         if (comport) {
  90                 udbg_comport = (struct NS16550 __iomem *)comport;
  91                 out_8(&udbg_comport->lcr, 0x00);
  92                 out_8(&udbg_comport->ier, 0xff);
  93                 out_8(&udbg_comport->ier, 0x00);
  94                 out_8(&udbg_comport->lcr, 0x80);        /* Access baud rate */
  95                 out_8(&udbg_comport->dll, dll & 0xff);  /* 1 = 115200,  2 = 57600,
  96                                                            3 = 38400, 12 = 9600 baud */
  97                 out_8(&udbg_comport->dlm, dll >> 8);    /* dll >> 8 which should be zero
  98                                                            for fast rates; */
  99                 out_8(&udbg_comport->lcr, 0x03);        /* 8 data, 1 stop, no parity */
 100                 out_8(&udbg_comport->mcr, 0x03);        /* RTS/DTR */
 101                 out_8(&udbg_comport->fcr ,0x07);        /* Clear & enable FIFOs */
 102                 ppc_md.udbg_putc = udbg_550_putc;
 103                 ppc_md.udbg_getc = udbg_550_getc;
 104                 ppc_md.udbg_getc_poll = udbg_550_getc_poll;
 105         }
 106 }
 107
 108 #ifdef CONFIG_PPC_MAPLE
 109 void udbg_maple_real_putc(unsigned char c)
 110 {
 111         if (udbg_comport) {
 112                 while ((real_readb(&udbg_comport->lsr) & LSR_THRE) == 0)
 113                         /* wait for idle */;
 114                 real_writeb(c, &udbg_comport->thr); eieio();
 115                 if (c == '\n')
 116                         udbg_maple_real_putc('\r');
 117         }
 118 }
 119
 120 void udbg_init_maple_realmode(void)
 121 {
 122         udbg_comport = (volatile struct NS16550 __iomem *)0xf40003f8;
 123
 124         ppc_md.udbg_putc = udbg_maple_real_putc;
 125         ppc_md.udbg_getc = NULL;
 126         ppc_md.udbg_getc_poll = NULL;
 127 }
 128 #endif /* CONFIG_PPC_MAPLE */