LXR linux/drivers/char/hvc

   1/*
   2 * IBM RTAS driver interface to hvc_console.c
   3 *
   4 * (C) Copyright IBM Corporation 2001-2005
   5 * (C) Copyright Red Hat, Inc. 2005
   6 *
   7 * Author(s): Maximino Augilar <IBM STI Design Center>
   8 *          : Ryan S. Arnold <rsa@us.ibm.com>
   9 *          : Utz Bacher <utz.bacher@de.ibm.com>
  10 *          : David Woodhouse <dwmw2@infradead.org>
  11 *
  12 *    inspired by drivers/char/hvc_console.c
  13 *    written by Anton Blanchard and Paul Mackerras
  14 *
  15 * This program is free software; you can redistribute it and/or modify
  16 * it under the terms of the GNU General Public License as published by
  17 * the Free Software Foundation; either version 2 of the License, or
  18 * (at your option) any later version.
  19 *
  20 * This program is distributed in the hope that it will be useful,
  21 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  22 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  23 * GNU General Public License for more details.
  24 *
  25 * You should have received a copy of the GNU General Public License
  26 * along with this program; if not, write to the Free Software
  27 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  28 */
  29
  30#include <linux/console.h>
  31#include <linux/delay.h>
  32#include <linux/err.h>
  33#include <linux/init.h>
  34#include <linux/moduleparam.h>
  35#include <linux/types.h>
  36
  37#include <asm/irq.h>
  38#include <asm/rtas.h>
  39#include "hvc_console.h"
  40
  41#define hvc_rtas_cookie 0x67781e15
  42struct hvc_struct *hvc_rtas_dev;
  43
  44static int rtascons_put_char_token = RTAS_UNKNOWN_SERVICE;
  45static int rtascons_get_char_token = RTAS_UNKNOWN_SERVICE;
  46
  47static inline int hvc_rtas_write_console(uint32_t vtermno, const char *buf,
  48                int count)
  49{
  50        int i;
  51
  52        for (i = 0; i < count; i++) {
  53                if (rtas_call(rtascons_put_char_token, 1, 1, NULL, buf[i]))
  54                        break;
  55        }
  56
  57        return i;
  58}
  59
  60static int hvc_rtas_read_console(uint32_t vtermno, char *buf, int count)
  61{
  62        int i, c;
  63
  64        for (i = 0; i < count; i++) {
  65                if (rtas_call(rtascons_get_char_token, 0, 2, &c))
  66                        break;
  67
  68                buf[i] = c;
  69        }
  70
  71        return i;
  72}
  73
  74static struct hv_ops hvc_rtas_get_put_ops = {
  75        .get_chars = hvc_rtas_read_console,
  76        .put_chars = hvc_rtas_write_console,
  77};
  78
  79static int __init hvc_rtas_init(void)
  80{
  81        struct hvc_struct *hp;
  82
  83        if (rtascons_put_char_token == RTAS_UNKNOWN_SERVICE)
  84                rtascons_put_char_token = rtas_token("put-term-char");
  85        if (rtascons_put_char_token == RTAS_UNKNOWN_SERVICE)
  86                return -EIO;
  87
  88        if (rtascons_get_char_token == RTAS_UNKNOWN_SERVICE)
  89                rtascons_get_char_token = rtas_token("get-term-char");
  90        if (rtascons_get_char_token == RTAS_UNKNOWN_SERVICE)
  91                return -EIO;
  92
  93        BUG_ON(hvc_rtas_dev);
  94
  95        /* Allocate an hvc_struct for the console device we instantiated
  96         * earlier.  Save off hp so that we can return it on exit */
  97        hp = hvc_alloc(hvc_rtas_cookie, NO_IRQ, &hvc_rtas_get_put_ops, 16);
  98        if (IS_ERR(hp))
  99                return PTR_ERR(hp);
 100
 101        hvc_rtas_dev = hp;
 102
 103        return 0;
 104}
 105module_init(hvc_rtas_init);
 106
 107/* This will tear down the tty portion of the driver */
 108static void __exit hvc_rtas_exit(void)
 109{
 110        /* Really the fun isn't over until the worker thread breaks down and
 111         * the tty cleans up */
 112        if (hvc_rtas_dev)
 113                hvc_remove(hvc_rtas_dev);
 114}
 115module_exit(hvc_rtas_exit);
 116
 117/* This will happen prior to module init.  There is no tty at this time? */
 118static int __init hvc_rtas_console_init(void)
 119{
 120        rtascons_put_char_token = rtas_token("put-term-char");
 121        if (rtascons_put_char_token == RTAS_UNKNOWN_SERVICE)
 122                return -EIO;
 123
 124        rtascons_get_char_token = rtas_token("get-term-char");
 125        if (rtascons_get_char_token == RTAS_UNKNOWN_SERVICE)
 126                return -EIO;
 127
 128        hvc_instantiate(hvc_rtas_cookie, 0, &hvc_rtas_get_put_ops);
 129        add_preferred_console("hvc", 0, NULL);
 130
 131        return 0;
 132}
 133console_initcall(hvc_rtas_console_init);
 134