arch/powerpc/platforms/cell/beat_udbg.c

   1 /*
   2  * udbg function for Beat
   3  *
   4  * (C) Copyright 2006 TOSHIBA CORPORATION
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with this program; if not, write to the Free Software Foundation, Inc.,
  18  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  19  */
  20
  21 #include <linux/kernel.h>
  22 #include <linux/console.h>
  23
  24 #include <asm/machdep.h>
  25 #include <asm/prom.h>
  26 #include <asm/udbg.h>
  27
  28 #include "beat.h"
  29
  30 #define celleb_vtermno  0
  31
  32 static void udbg_putc_beat(char c)
  33 {
  34         unsigned long rc;
  35
  36         if (c == '\n')
  37                 udbg_putc_beat('\r');
  38
  39         rc = beat_put_term_char(celleb_vtermno, 1, (uint64_t)c << 56, 0);
  40 }
  41
  42 /* Buffered chars getc */
  43 static u64 inbuflen;
  44 static u64 inbuf[2];    /* must be 2 u64s */
  45
  46 static int udbg_getc_poll_beat(void)
  47 {
  48         /* The interface is tricky because it may return up to 16 chars.
  49          * We save them statically for future calls to udbg_getc().
  50          */
  51         char ch, *buf = (char *)inbuf;
  52         int i;
  53         long rc;
  54         if (inbuflen == 0) {
  55                 /* get some more chars. */
  56                 inbuflen = 0;
  57                 rc = beat_get_term_char(celleb_vtermno, &inbuflen,
  58                                         inbuf+0, inbuf+1);
  59                 if (rc != 0)
  60                         inbuflen = 0;   /* otherwise inbuflen is garbage */
  61         }
  62         if (inbuflen <= 0 || inbuflen > 16) {
  63                 /* Catch error case as well as other oddities (corruption) */
  64                 inbuflen = 0;
  65                 return -1;
  66         }
  67         ch = buf[0];
  68         for (i = 1; i < inbuflen; i++)  /* shuffle them down. */
  69                 buf[i-1] = buf[i];
  70         inbuflen--;
  71         return ch;
  72 }
  73
  74 static int udbg_getc_beat(void)
  75 {
  76         int ch;
  77         for (;;) {
  78                 ch = udbg_getc_poll_beat();
  79                 if (ch == -1) {
  80                         /* This shouldn't be needed...but... */
  81                         volatile unsigned long delay;
  82                         for (delay = 0; delay < 2000000; delay++)
  83                                 ;
  84                 } else {
  85                         return ch;
  86                 }
  87         }
  88 }
  89
  90 /* call this from early_init() for a working debug console on
  91  * vterm capable LPAR machines
  92  */
  93 void __init udbg_init_debug_beat(void)
  94 {
  95         udbg_putc = udbg_putc_beat;
  96         udbg_getc = udbg_getc_beat;
  97         udbg_getc_poll = udbg_getc_poll_beat;
  98 }