speed.c

/*
 *
 * Copyright (C) 2004-2007, 2012 Freescale Semiconductor, Inc.
 * TsiChung Liew (Tsi-Chung.Liew@freescale.com)
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * 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 <common.h>
#include <asm/processor.h>

#include <asm/immap.h>
#include <asm/io.h>

DECLARE_GLOBAL_DATA_PTR;

/*
 * Low Power Divider specifications
 */
#define CLOCK_LPD_MIN		(1 << 0)	/* Divider (decoded) */
#define CLOCK_LPD_MAX		(1 << 15)	/* Divider (decoded) */

#define CLOCK_PLL_FVCO_MAX	540000000
#define CLOCK_PLL_FVCO_MIN	300000000

#define CLOCK_PLL_FSYS_MAX	266666666
#define CLOCK_PLL_FSYS_MIN	100000000
#define MHZ			1000000

void clock_enter_limp(int lpdiv)
{
	ccm_t *ccm = (ccm_t *)MMAP_CCM;
	int i, j;

	/* Check bounds of divider */
	if (lpdiv < CLOCK_LPD_MIN)
		lpdiv = CLOCK_LPD_MIN;
	if (lpdiv > CLOCK_LPD_MAX)
		lpdiv = CLOCK_LPD_MAX;

	/* Round divider down to nearest power of two */
	for (i = 0, j = lpdiv; j != 1; j >>= 1, i++) ;

#ifdef CONFIG_MCF5445x
	/* Apply the divider to the system clock */
	clrsetbits_be16(&ccm->cdr, 0x0f00, CCM_CDR_LPDIV(i));
#endif

	/* Enable Limp Mode */
	setbits_be16(&ccm->misccr, CCM_MISCCR_LIMP);
}

/*
 * brief   Exit Limp mode