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/naca.h>
  16 #include <asm/io.h>
  17 #include <asm/prom.h>
  18 #include <asm/pmac_feature.h>
  19
  20 extern u8 real_readb(volatile u8 __iomem  *addr);
  21 extern void real_writeb(u8 data, volatile u8 __iomem *addr);
  22
  23 #define SCC_TXRDY       4
  24 #define SCC_RXRDY       1
  25
  26 static volatile u8 __iomem *sccc;
  27 static volatile u8 __iomem *sccd;
  28
  29 static void udbg_scc_putc(unsigned char c)
  30 {
  31         if (sccc) {
  32                 while ((in_8(sccc) & SCC_TXRDY) == 0)
  33                         ;
  34                 out_8(sccd,  c);
  35                 if (c == '\n')
  36                         udbg_scc_putc('\r');
  37         }
  38 }
  39
  40 static int udbg_scc_getc_poll(void)
  41 {
  42         if (sccc) {
  43                 if ((in_8(sccc) & SCC_RXRDY) != 0)
  44                         return in_8(sccd);
  45                 else
  46                         return -1;
  47         }
  48         return -1;
  49 }
  50
  51 static unsigned char udbg_scc_getc(void)
  52 {
  53         if (sccc) {
  54                 while ((in_8(sccc) & SCC_RXRDY) == 0)
  55                         ;
  56                 return in_8(sccd);
  57         }
  58         return 0;
  59 }
  60
  61 static unsigned char scc_inittab[] = {
  62     13, 0,              /* set baud rate divisor */
  63     12, 0,
  64     14, 1,              /* baud rate gen enable, src=rtxc */
  65     11, 0x50,           /* clocks = br gen */
  66     5,  0xea,           /* tx 8 bits, assert DTR & RTS */
  67     4,  0x46,           /* x16 clock, 1 stop */
  68     3,  0xc1,           /* rx enable, 8 bits */
  69 };
  70
  71 void udbg_init_scc(struct device_node *np)
  72 {
  73         u32 *reg;
  74         unsigned long addr;
  75         int i, x;
  76
  77         if (np == NULL)
  78                 np = of_find_node_by_name(NULL, "escc");
  79         if (np == NULL || np->parent == NULL)
  80                 return;
  81
  82         udbg_printf("found SCC...\n");
  83         /* Get address within mac-io ASIC */
  84         reg = (u32 *)get_property(np, "reg", NULL);
  85         if (reg == NULL)
  86                 return;
  87         addr = reg[0];
  88         udbg_printf("local addr: %lx\n", addr);
  89         /* Get address of mac-io PCI itself */
  90         reg = (u32 *)get_property(np->parent, "assigned-addresses", NULL);
  91         if (reg == NULL)
  92                 return;
  93         addr += reg[2];
  94         udbg_printf("final addr: %lx\n", addr);
  95
  96         /* Setup for 57600 8N1 */
  97         addr += 0x20;
  98         sccc = (volatile u8 * __iomem) ioremap(addr & PAGE_MASK, PAGE_SIZE) ;
  99         sccc += addr & ~PAGE_MASK;
 100         sccd = sccc + 0x10;
 101
 102         udbg_printf("ioremap result sccc: %p\n", sccc);
 103         mb();
 104
 105         for (i = 20000; i != 0; --i)
 106                 x = in_8(sccc);
 107         out_8(sccc, 0x09);              /* reset A or B side */
 108         out_8(sccc, 0xc0);
 109         for (i = 0; i < sizeof(scc_inittab); ++i)
 110                 out_8(sccc, scc_inittab[i]);
 111
 112         udbg_putc = udbg_scc_putc;
 113         udbg_getc = udbg_scc_getc;
 114         udbg_getc_poll = udbg_scc_getc_poll;
 115
 116         udbg_puts("Hello World !\n");
 117 }
 118
 119 static void udbg_real_scc_putc(unsigned char c)
 120 {
 121         while ((real_readb(sccc) & SCC_TXRDY) == 0)
 122                 ;
 123         real_writeb(c, sccd);
 124         if (c == '\n')
 125                 udbg_real_scc_putc('\r');
 126 }
 127
 128 void udbg_init_pmac_realmode(void)
 129 {
 130         sccc = (volatile u8 __iomem *)0x80013020ul;
 131         sccd = (volatile u8 __iomem *)0x80013030ul;
 132
 133         udbg_putc = udbg_real_scc_putc;
 134         udbg_getc = NULL;
 135         udbg_getc_poll = NULL;
 136 }