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kernel/linux-imx6_3.14.28/arch/powerpc/boot/mpc8xx.c 1.65 KB
6b13f685e   김민수   BSP 최초 추가
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  /*
   * MPC8xx support functions
   *
   * Author: Scott Wood <scottwood@freescale.com>
   *
   * Copyright (c) 2007 Freescale Semiconductor, Inc.
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 as published
   * by the Free Software Foundation.
   */
  
  #include "ops.h"
  #include "types.h"
  #include "fsl-soc.h"
  #include "mpc8xx.h"
  #include "stdio.h"
  #include "io.h"
  
  #define MPC8XX_PLPRCR (0x284/4) /* PLL and Reset Control Register */
  
  /* Return system clock from crystal frequency */
  u32 mpc885_get_clock(u32 crystal)
  {
  	u32 *immr;
  	u32 plprcr;
  	int mfi, mfn, mfd, pdf, div;
  	u32 ret;
  
  	immr = fsl_get_immr();
  	if (!immr) {
  		printf("mpc885_get_clock: Couldn't get IMMR base.\r
  ");
  		return 0;
  	}
  
  	plprcr = in_be32(&immr[MPC8XX_PLPRCR]);
  
  	mfi = (plprcr >> 16) & 15;
  	if (mfi < 5) {
  		printf("Warning: PLPRCR[MFI] value of %d out-of-bounds\r
  ",
  		       mfi);
  		mfi = 5;
  	}
  
  	pdf = (plprcr >> 1) & 0xf;
  	div = (plprcr >> 20) & 3;
  	mfd = (plprcr >> 22) & 0x1f;
  	mfn = (plprcr >> 27) & 0x1f;
  
  	ret = crystal * mfi;
  
  	if (mfn != 0)
  		ret += crystal * mfn / (mfd + 1);
  
  	return ret / (pdf + 1);
  }
  
  /* Set common device tree fields based on the given clock frequencies. */
  void mpc8xx_set_clocks(u32 sysclk)
  {
  	void *node;
  
  	dt_fixup_cpu_clocks(sysclk, sysclk / 16, sysclk);
  
  	node = finddevice("/soc/cpm");
  	if (node)
  		setprop(node, "clock-frequency", &sysclk, 4);
  
  	node = finddevice("/soc/cpm/brg");
  	if (node)
  		setprop(node, "clock-frequency", &sysclk, 4);
  }
  
  int mpc885_fixup_clocks(u32 crystal)
  {
  	u32 sysclk = mpc885_get_clock(crystal);
  	if (!sysclk)
  		return 0;
  
  	mpc8xx_set_clocks(sysclk);
  	return 1;
  }