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kernel/linux-imx6_3.14.28/arch/arm/mach-imx/cpu-imx27.c 1.87 KB
6b13f685e   김민수   BSP 최초 추가
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  /*
   * Copyright 2007 Freescale Semiconductor, Inc. All Rights Reserved.
   * Copyright 2008 Juergen Beisert, kernel@pengutronix.de
   *
   * 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., 51 Franklin Street, Fifth Floor, Boston,
   * MA 02110-1301, USA.
   */
  
  /*
   * i.MX27 specific CPU detection code
   */
  
  #include <linux/io.h>
  #include <linux/module.h>
  
  #include "hardware.h"
  
  static int mx27_cpu_rev = -1;
  static int mx27_cpu_partnumber;
  
  #define SYS_CHIP_ID             0x00    /* The offset of CHIP ID register */
  
  static int mx27_read_cpu_rev(void)
  {
  	u32 val;
  	/*
  	 * now we have access to the IO registers. As we need
  	 * the silicon revision very early we read it here to
  	 * avoid any further hooks
  	*/
  	val = __raw_readl(MX27_IO_ADDRESS(MX27_SYSCTRL_BASE_ADDR
  				+ SYS_CHIP_ID));
  
  	mx27_cpu_partnumber = (int)((val >> 12) & 0xFFFF);
  
  	switch (val >> 28) {
  	case 0:
  		return IMX_CHIP_REVISION_1_0;
  	case 1:
  		return IMX_CHIP_REVISION_2_0;
  	case 2:
  		return IMX_CHIP_REVISION_2_1;
  	default:
  		return IMX_CHIP_REVISION_UNKNOWN;
  	}
  }
  
  /*
   * Returns:
   *	the silicon revision of the cpu
   *	-EINVAL - not a mx27
   */
  int mx27_revision(void)
  {
  	if (mx27_cpu_rev == -1)
  		mx27_cpu_rev = mx27_read_cpu_rev();
  
  	if (mx27_cpu_partnumber != 0x8821)
  		return -EINVAL;
  
  	return mx27_cpu_rev;
  }
  EXPORT_SYMBOL(mx27_revision);