u-boot/cpu/74xx_7xx/speed.c

/*
 * (C) Copyright 2000-2002
 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 *
 * 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 <74xx_7xx.h>
#include <asm/processor.h>

#ifdef CONFIG_AMIGAONEG3SE
#include "../board/MAI/AmigaOneG3SE/via686.h"
#endif

static const int hid1_multipliers_x_10[] = {
	25,	/* 0000 - 2.5x */
	75,	/* 0001 - 7.5x */
	70,	/* 0010 - 7x */
	10,	/* 0011 - bypass */
	20,	/* 0100 - 2x */
	65,	/* 0101 - 6.5x */
	100,	/* 0110 - 10x */
	45,	/* 0111 - 4.5x */
	30,	/* 1000 - 3x */
	55,	/* 1001 - 5.5x */
	40,	/* 1010 - 4x */
	50,	/* 1011 - 5x */
	80,	/* 1100 - 8x */
	60,	/* 1101 - 6x */
	35,	/* 1110 - 3.5x */
	0	/* 1111 - off */
};

static const int hid1_fx_multipliers_x_10[] = {
	00,	/* 0000 - off */
	00,	/* 0001 - off */
	10,	/* 0010 - bypass */
	10,	/* 0011 - bypass */
	20,	/* 0100 - 2x */
	25,	/* 0101 - 2.5x */
	30,	/* 0110 - 3x */
	35,	/* 0111 - 3.5x */
	40,	/* 1000 - 4x */
	45,	/* 1001 - 4.5x */
	50,	/* 1010 - 5x */
	55,	/* 1011 - 5.5x */
	60,	/* 1100 - 6x */
	65,	/* 1101 - 6.5x */
	70,	/* 1110 - 7x */
	75,	/* 1111 - 7.5 */
	80,	/* 10000 - 8x */
	85,	/* 10001 - 8.5x */
	90,	/* 10010 - 9x */
	95,	/* 10011 - 9.5x */
	100,	/* 10100 - 10x */
	110,	/* 10101 - 11x */
	120,	/* 10110 - 12x */
};


/* ------------------------------------------------------------------------- */

/*
 * Measure CPU clock speed (core clock GCLK1, GCLK2)
 *
 * (Approx. GCLK frequency in Hz)
 */

int get_clocks (void)
{
	DECLARE_GLOBAL_DATA_PTR;
	ulong clock = 0;

	/* calculate the clock frequency based upon the CPU type */
	switch (get_cpu_type()) {
	case CPU_7455:
	case CPU_7457:
		/*
		 * It is assumed that the PLL_EXT line is zero.
		 * Make sure division is done before multiplication to prevent 32-bit
		 * arithmetic overflows which will cause a negative number
		 */
		clock = (CFG_BUS_CLK / 10) * hid1_multipliers_x_10[(get_hid1 () >> 13) & 0xF];
		break;

	case CPU_750GX:
	case CPU_750FX:
		clock = CFG_BUS_CLK * hid1_fx_multipliers_x_10[get_hid1 () >> 27] / 10;
		break;

	case CPU_7450:
	case CPU_740:
	case CPU_740P:
	case CPU_745:
	case CPU_750CX:
	case CPU_750:
	case CPU_750P:
	case CPU_755:
	case CPU_7400:
	case CPU_7410:
		/*
		 * Make sure division is done before multiplication to prevent 32-bit
		 * arithmetic overflows which will cause a negative number
		 */
		clock = (CFG_BUS_CLK / 10) * hid1_multipliers_x_10[get_hid1 () >> 28];
		break;

	case CPU_UNKNOWN:
	       printf ("get_gclk_freq(): unknown CPU type\n");
	       clock = 0;
	       return (1);
	}

	gd->cpu_clk = clock;
	gd->bus_clk = CFG_BUS_CLK;

	return (0);
}

/* ------------------------------------------------------------------------- */