drivers/tty/hvc/hvc_udbg.c

   1 /*
   2  * udbg interface to hvc_console.c
   3  *
   4  * (C) Copyright David Gibson, IBM Corporation 2008.
   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
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  19  */
  20
  21 #include <linux/console.h>
  22 #include <linux/delay.h>
  23 #include <linux/err.h>
  24 #include <linux/init.h>
  25 #include <linux/moduleparam.h>
  26 #include <linux/types.h>
  27 #include <linux/irq.h>
  28
  29 #include <asm/udbg.h>
  30
  31 #include "hvc_console.h"
  32
  33 struct hvc_struct *hvc_udbg_dev;
  34
  35 static int hvc_udbg_put(uint32_t vtermno, const char *buf, int count)
  36 {
  37         int i;
  38
  39         for (i = 0; i < count && udbg_putc; i++)
  40                 udbg_putc(buf[i]);
  41
  42         return i;
  43 }
  44
  45 static int hvc_udbg_get(uint32_t vtermno, char *buf, int count)
  46 {
  47         int i, c;
  48
  49         if (!udbg_getc_poll)
  50                 return 0;
  51
  52         for (i = 0; i < count; i++) {
  53                 if ((c = udbg_getc_poll()) == -1)
  54                         break;
  55                 buf[i] = c;
  56         }
  57
  58         return i;
  59 }
  60
  61 static const struct hv_ops hvc_udbg_ops = {
  62         .get_chars = hvc_udbg_get,
  63         .put_chars = hvc_udbg_put,
  64 };
  65
  66 static int __init hvc_udbg_init(void)
  67 {
  68         struct hvc_struct *hp;
  69
  70         if (!udbg_putc)
  71                 return -ENODEV;
  72
  73         BUG_ON(hvc_udbg_dev);
  74
  75         hp = hvc_alloc(0, NO_IRQ, &hvc_udbg_ops, 16);
  76         if (IS_ERR(hp))
  77                 return PTR_ERR(hp);
  78
  79         hvc_udbg_dev = hp;
  80
  81         return 0;
  82 }
  83 module_init(hvc_udbg_init);
  84
  85 static void __exit hvc_udbg_exit(void)
  86 {
  87         if (hvc_udbg_dev)
  88                 hvc_remove(hvc_udbg_dev);
  89 }
  90 module_exit(hvc_udbg_exit);
  91
  92 static int __init hvc_udbg_console_init(void)
  93 {
  94         if (!udbg_putc)
  95                 return -ENODEV;
  96
  97         hvc_instantiate(0, 0, &hvc_udbg_ops);
  98         add_preferred_console("hvc", 0, NULL);
  99
 100         return 0;
 101 }
 102 console_initcall(hvc_udbg_console_init);