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hvc_rtas.c

/*
 * IBM RTAS driver interface to hvc_console.c
 *
 * (C) Copyright IBM Corporation 2001-2005
 * (C) Copyright Red Hat, Inc. 2005
 *
 * Author(s): Maximino Augilar <IBM STI Design Center>
 *        : Ryan S. Arnold <rsa@us.ibm.com>
 *        : Utz Bacher <utz.bacher@de.ibm.com>
 *        : David Woodhouse <dwmw2@infradead.org>
 *
 *    inspired by drivers/char/hvc_console.c
 *    written by Anton Blanchard and Paul Mackerras
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */

#include <linux/console.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/moduleparam.h>
#include <linux/types.h>

#include <asm/irq.h>
#include <asm/rtas.h>
#include "hvc_console.h"

#define hvc_rtas_cookie 0x67781e15
struct hvc_struct *hvc_rtas_dev;

static int rtascons_put_char_token = RTAS_UNKNOWN_SERVICE;
static int rtascons_get_char_token = RTAS_UNKNOWN_SERVICE;

static inline int hvc_rtas_write_console(uint32_t vtermno, const char *buf,
            int count)
{
      int i;

      for (i = 0; i < count; i++) {
            if (rtas_call(rtascons_put_char_token, 1, 1, NULL, buf[i]))
                  break;
      }

      return i;
}

static int hvc_rtas_read_console(uint32_t vtermno, char *buf, int count)
{
      int i, c;

      for (i = 0; i < count; i++) {
            if (rtas_call(rtascons_get_char_token, 0, 2, &c))
                  break;

            buf[i] = c;
      }

      return i;
}

static struct hv_ops hvc_rtas_get_put_ops = {
      .get_chars = hvc_rtas_read_console,
      .put_chars = hvc_rtas_write_console,
};

static int hvc_rtas_init(void)
{
      struct hvc_struct *hp;

      if (rtascons_put_char_token == RTAS_UNKNOWN_SERVICE)
            rtascons_put_char_token = rtas_token("put-term-char");
      if (rtascons_put_char_token == RTAS_UNKNOWN_SERVICE)
            return -EIO;

      if (rtascons_get_char_token == RTAS_UNKNOWN_SERVICE)
            rtascons_get_char_token = rtas_token("get-term-char");
      if (rtascons_get_char_token == RTAS_UNKNOWN_SERVICE)
            return -EIO;

      BUG_ON(hvc_rtas_dev);

      /* Allocate an hvc_struct for the console device we instantiated
       * earlier.  Save off hp so that we can return it on exit */
      hp = hvc_alloc(hvc_rtas_cookie, NO_IRQ, &hvc_rtas_get_put_ops, 16);
      if (IS_ERR(hp))
            return PTR_ERR(hp);

      hvc_rtas_dev = hp;

      return 0;
}
module_init(hvc_rtas_init);

/* This will tear down the tty portion of the driver */
static void __exit hvc_rtas_exit(void)
{
      /* Really the fun isn't over until the worker thread breaks down and
       * the tty cleans up */
      if (hvc_rtas_dev)
            hvc_remove(hvc_rtas_dev);
}
module_exit(hvc_rtas_exit);

/* This will happen prior to module init.  There is no tty at this time? */
static int __init hvc_rtas_console_init(void)
{
      rtascons_put_char_token = rtas_token("put-term-char");
      if (rtascons_put_char_token == RTAS_UNKNOWN_SERVICE)
            return -EIO;

      rtascons_get_char_token = rtas_token("get-term-char");
      if (rtascons_get_char_token == RTAS_UNKNOWN_SERVICE)
            return -EIO;

      hvc_instantiate(hvc_rtas_cookie, 0, &hvc_rtas_get_put_ops);
      add_preferred_console("hvc", 0, NULL);

      return 0;
}
console_initcall(hvc_rtas_console_init);

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