arch/ppc64/kernel/udbg_scc.c

   1 /*
   2  * udbg for for zilog scc ports as found on Apple PowerMacs
   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/processor.h>
  15 #include <asm/io.h>
  16 #include <asm/prom.h>
  17 #include <asm/pmac_feature.h>
  18
  19 extern u8 real_readb(volatile u8 __iomem  *addr);
  20 extern void real_writeb(u8 data, volatile u8 __iomem *addr);
  21
  22 #define SCC_TXRDY       4
  23 #define SCC_RXRDY       1
  24
  25 static volatile u8 __iomem *sccc;
  26 static volatile u8 __iomem *sccd;
  27
  28 static void udbg_scc_putc(unsigned char c)
  29 {
  30         if (sccc) {
  31                 while ((in_8(sccc) & SCC_TXRDY) == 0)
  32                         ;
  33                 out_8(sccd,  c);
  34                 if (c == '\n')
  35                         udbg_scc_putc('\r');
  36         }
  37 }
  38
  39 static int udbg_scc_getc_poll(void)
  40 {
  41         if (sccc) {
  42                 if ((in_8(sccc) & SCC_RXRDY) != 0)
  43                         return in_8(sccd);
  44                 else
  45                         return -1;
  46         }
  47         return -1;
  48 }
  49
  50 static unsigned char udbg_scc_getc(void)
  51 {
  52         if (sccc) {
  53                 while ((in_8(sccc) & SCC_RXRDY) == 0)
  54                         ;
  55                 return in_8(sccd);
  56         }
  57         return 0;
  58 }
  59
  60 static unsigned char scc_inittab[] = {
  61     13, 0,              /* set baud rate divisor */
  62     12, 0,
  63     14, 1,              /* baud rate gen enable, src=rtxc */
  64     11, 0x50,           /* clocks = br gen */
  65     5,  0xea,           /* tx 8 bits, assert DTR & RTS */
  66     4,  0x46,           /* x16 clock, 1 stop */
  67     3,  0xc1,           /* rx enable, 8 bits */
  68 };
  69
  70 void udbg_init_scc(struct device_node *np)
  71 {
  72         u32 *reg;
  73         unsigned long addr;
  74         int i, x;
  75
  76         if (np == NULL)
  77                 np = of_find_node_by_name(NULL, "escc");
  78         if (np == NULL || np->parent == NULL)
  79                 return;
  80
  81         udbg_printf("found SCC...\n");
  82         /* Get address within mac-io ASIC */
  83         reg = (u32 *)get_property(np, "reg", NULL);
  84         if (reg == NULL)
  85                 return;
  86         addr = reg[0];
  87         udbg_printf("local addr: %lx\n", addr);
  88         /* Get address of mac-io PCI itself */
  89         reg = (u32 *)get_property(np->parent, "assigned-addresses", NULL);
  90         if (reg == NULL)
  91                 return;
  92         addr += reg[2];
  93         udbg_printf("final addr: %lx\n", addr);
  94
  95         /* Setup for 57600 8N1 */
  96         addr += 0x20;
  97         sccc = (volatile u8 * __iomem) ioremap(addr & PAGE_MASK, PAGE_SIZE) ;
  98         sccc += addr & ~PAGE_MASK;
  99         sccd = sccc + 0x10;
 100
 101         udbg_printf("ioremap result sccc: %p\n", sccc);
 102         mb();
 103
 104         for (i = 20000; i != 0; --i)
 105                 x = in_8(sccc);
 106         out_8(sccc, 0x09);              /* reset A or B side */
 107         out_8(sccc, 0xc0);
 108         for (i = 0; i < sizeof(scc_inittab); ++i)
 109                 out_8(sccc, scc_inittab[i]);
 110
 111         udbg_putc = udbg_scc_putc;
 112         udbg_getc = udbg_scc_getc;
 113         udbg_getc_poll = udbg_scc_getc_poll;
 114
 115         udbg_puts("Hello World !\n");
 116 }
 117
 118 static void udbg_real_scc_putc(unsigned char c)
 119 {
 120         while ((real_readb(sccc) & SCC_TXRDY) == 0)
 121                 ;
 122         real_writeb(c, sccd);
 123         if (c == '\n')
 124                 udbg_real_scc_putc('\r');
 125 }
 126
 127 void udbg_init_pmac_realmode(void)
 128 {
 129         sccc = (volatile u8 __iomem *)0x80013020ul;
 130         sccd = (volatile u8 __iomem *)0x80013030ul;
 131
 132         udbg_putc = udbg_real_scc_putc;
 133         udbg_getc = NULL;
 134         udbg_getc_poll = NULL;
 135 }