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kernel/linux-rt-4.4.41/drivers/tty/hvc/hvc_udbg.c 2 KB
5113f6f70   김현기   kernel add
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  /*
   * udbg interface to hvc_console.c
   *
   * (C) Copyright David Gibson, IBM Corporation 2008.
   *
   * 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 <linux/irq.h>
  
  #include <asm/udbg.h>
  
  #include "hvc_console.h"
  
  struct hvc_struct *hvc_udbg_dev;
  
  static int hvc_udbg_put(uint32_t vtermno, const char *buf, int count)
  {
  	int i;
  
  	for (i = 0; i < count && udbg_putc; i++)
  		udbg_putc(buf[i]);
  
  	return i;
  }
  
  static int hvc_udbg_get(uint32_t vtermno, char *buf, int count)
  {
  	int i, c;
  
  	if (!udbg_getc_poll)
  		return 0;
  
  	for (i = 0; i < count; i++) {
  		if ((c = udbg_getc_poll()) == -1)
  			break;
  		buf[i] = c;
  	}
  
  	return i;
  }
  
  static const struct hv_ops hvc_udbg_ops = {
  	.get_chars = hvc_udbg_get,
  	.put_chars = hvc_udbg_put,
  };
  
  static int __init hvc_udbg_init(void)
  {
  	struct hvc_struct *hp;
  
  	if (!udbg_putc)
  		return -ENODEV;
  
  	BUG_ON(hvc_udbg_dev);
  
  	hp = hvc_alloc(0, 0, &hvc_udbg_ops, 16);
  	if (IS_ERR(hp))
  		return PTR_ERR(hp);
  
  	hvc_udbg_dev = hp;
  
  	return 0;
  }
  device_initcall(hvc_udbg_init);
  
  static int __init hvc_udbg_console_init(void)
  {
  	if (!udbg_putc)
  		return -ENODEV;
  
  	hvc_instantiate(0, 0, &hvc_udbg_ops);
  	add_preferred_console("hvc", 0, NULL);
  
  	return 0;
  }
  console_initcall(hvc_udbg_console_init);