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kernel/linux-rt-4.4.41/drivers/tty/hvc/hvc_rtas.c 3.32 KB
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  /*
   * 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 const struct hv_ops hvc_rtas_get_put_ops = {
  	.get_chars = hvc_rtas_read_console,
  	.put_chars = hvc_rtas_write_console,
  };
  
  static int __init 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, 0, &hvc_rtas_get_put_ops, 16);
  	if (IS_ERR(hp))
  		return PTR_ERR(hp);
  
  	hvc_rtas_dev = hp;
  
  	return 0;
  }
  device_initcall(hvc_rtas_init);
  
  /* 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);