LXR linux/arch/powerpc/platforms/powermac/udbg

   1/*
   2 * udbg 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/types.h>
  12#include <asm/udbg.h>
  13#include <asm/processor.h>
  14#include <asm/io.h>
  15#include <asm/prom.h>
  16#include <asm/pmac_feature.h>
  17
  18extern u8 real_readb(volatile u8 __iomem  *addr);
  19extern void real_writeb(u8 data, volatile u8 __iomem *addr);
  20
  21#define SCC_TXRDY       4
  22#define SCC_RXRDY       1
  23
  24static volatile u8 __iomem *sccc;
  25static volatile u8 __iomem *sccd;
  26
  27static void udbg_scc_putc(char c)
  28{
  29        if (sccc) {
  30                while ((in_8(sccc) & SCC_TXRDY) == 0)
  31                        ;
  32                out_8(sccd,  c);
  33                if (c == '\n')
  34                        udbg_scc_putc('\r');
  35        }
  36}
  37
  38static int udbg_scc_getc_poll(void)
  39{
  40        if (sccc) {
  41                if ((in_8(sccc) & SCC_RXRDY) != 0)
  42                        return in_8(sccd);
  43                else
  44                        return -1;
  45        }
  46        return -1;
  47}
  48
  49static int udbg_scc_getc(void)
  50{
  51        if (sccc) {
  52                while ((in_8(sccc) & SCC_RXRDY) == 0)
  53                        ;
  54                return in_8(sccd);
  55        }
  56        return -1;
  57}
  58
  59static unsigned char scc_inittab[] = {
  60    13, 0,              /* set baud rate divisor */
  61    12, 0,
  62    14, 1,              /* baud rate gen enable, src=rtxc */
  63    11, 0x50,           /* clocks = br gen */
  64    5,  0xea,           /* tx 8 bits, assert DTR & RTS */
  65    4,  0x46,           /* x16 clock, 1 stop */
  66    3,  0xc1,           /* rx enable, 8 bits */
  67};
  68
  69void udbg_scc_init(int force_scc)
  70{
  71        const u32 *reg;
  72        unsigned long addr;
  73        struct device_node *stdout = NULL, *escc = NULL, *macio = NULL;
  74        struct device_node *ch, *ch_def = NULL, *ch_a = NULL;
  75        const char *path;
  76        int i, x;
  77
  78        escc = of_find_node_by_name(NULL, "escc");
  79        if (escc == NULL)
  80                goto bail;
  81        macio = of_get_parent(escc);
  82        if (macio == NULL)
  83                goto bail;
  84        path = of_get_property(of_chosen, "linux,stdout-path", NULL);
  85        if (path != NULL)
  86                stdout = of_find_node_by_path(path);
  87        for (ch = NULL; (ch = of_get_next_child(escc, ch)) != NULL;) {
  88                if (ch == stdout)
  89                        ch_def = of_node_get(ch);
  90                if (strcmp(ch->name, "ch-a") == 0)
  91                        ch_a = of_node_get(ch);
  92        }
  93        if (ch_def == NULL && !force_scc)
  94                goto bail;
  95
  96        ch = ch_def ? ch_def : ch_a;
  97
  98        /* Get address within mac-io ASIC */
  99        reg = of_get_property(escc, "reg", NULL);
 100        if (reg == NULL)
 101                goto bail;
 102        addr = reg[0];
 103
 104        /* Get address of mac-io PCI itself */
 105        reg = of_get_property(macio, "assigned-addresses", NULL);
 106        if (reg == NULL)
 107                goto bail;
 108        addr += reg[2];
 109
 110        /* Lock the serial port */
 111        pmac_call_feature(PMAC_FTR_SCC_ENABLE, ch,
 112                          PMAC_SCC_ASYNC | PMAC_SCC_FLAG_XMON, 1);
 113
 114        if (ch == ch_a)
 115                addr += 0x20;
 116        sccc = ioremap(addr & PAGE_MASK, PAGE_SIZE) ;
 117        sccc += addr & ~PAGE_MASK;
 118        sccd = sccc + 0x10;
 119
 120        mb();
 121
 122        for (i = 20000; i != 0; --i)
 123                x = in_8(sccc);
 124        out_8(sccc, 0x09);              /* reset A or B side */
 125        out_8(sccc, 0xc0);
 126
 127        /* If SCC was the OF output port, read the BRG value, else
 128         * Setup for 38400 or 57600 8N1 depending on the machine
 129         */
 130        if (ch_def != NULL) {
 131                out_8(sccc, 13);
 132                scc_inittab[1] = in_8(sccc);
 133                out_8(sccc, 12);
 134                scc_inittab[3] = in_8(sccc);
 135        } else if (of_machine_is_compatible("RackMac1,1")
 136                   || of_machine_is_compatible("RackMac1,2")
 137                   || of_machine_is_compatible("MacRISC4")) {
 138                /* Xserves and G5s default to 57600 */
 139                scc_inittab[1] = 0;
 140                scc_inittab[3] = 0;
 141        } else {
 142                /* Others default to 38400 */
 143                scc_inittab[1] = 0;
 144                scc_inittab[3] = 1;
 145        }
 146
 147        for (i = 0; i < sizeof(scc_inittab); ++i)
 148                out_8(sccc, scc_inittab[i]);
 149
 150
 151        udbg_putc = udbg_scc_putc;
 152        udbg_getc = udbg_scc_getc;
 153        udbg_getc_poll = udbg_scc_getc_poll;
 154
 155        udbg_puts("Hello World !\n");
 156
 157 bail:
 158        of_node_put(macio);
 159        of_node_put(escc);
 160        of_node_put(stdout);
 161        of_node_put(ch_def);
 162        of_node_put(ch_a);
 163}
 164
 165#ifdef CONFIG_PPC64
 166static void udbg_real_scc_putc(char c)
 167{
 168        while ((real_readb(sccc) & SCC_TXRDY) == 0)
 169                ;
 170        real_writeb(c, sccd);
 171        if (c == '\n')
 172                udbg_real_scc_putc('\r');
 173}
 174
 175void __init udbg_init_pmac_realmode(void)
 176{
 177        sccc = (volatile u8 __iomem *)0x80013020ul;
 178        sccd = (volatile u8 __iomem *)0x80013030ul;
 179
 180        udbg_putc = udbg_real_scc_putc;
 181        udbg_getc = NULL;
 182        udbg_getc_poll = NULL;
 183}
 184#endif /* CONFIG_PPC64 */
 185