arch/arm/mach-pxa/pxa25x.c

/*
 *  linux/arch/arm/mach-pxa/pxa25x.c
 *
 *  Author:	Nicolas Pitre
 *  Created:	Jun 15, 2001
 *  Copyright:	MontaVista Software Inc.
 *
 * Code specific to PXA21x/25x/26x variants.
 *
 * 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.
 *
 * Since this file should be linked before any other machine specific file,
 * the __initcall() here will be executed first.  This serves as default
 * initialization stuff for PXA machines which can be overridden later if
 * need be.
 */
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/pm.h>

#include <asm/hardware.h>
#include <asm/arch/pxa-regs.h>

#include "generic.h"

/*
 * Various clock factors driven by the CCCR register.
 */

/* Crystal Frequency to Memory Frequency Multiplier (L) */
static unsigned char L_clk_mult[32] = { 0, 27, 32, 36, 40, 45, 0, };

/* Memory Frequency to Run Mode Frequency Multiplier (M) */
static unsigned char M_clk_mult[4] = { 0, 1, 2, 4 };

/* Run Mode Frequency to Turbo Mode Frequency Multiplier (N) */
/* Note: we store the value N * 2 here. */
static unsigned char N2_clk_mult[8] = { 0, 0, 2, 3, 4, 0, 6, 0 };

/* Crystal clock */
#define BASE_CLK	3686400

/*
 * Get the clock frequency as reflected by CCCR and the turbo flag.
 * We assume these values have been applied via a fcs.
 * If info is not 0 we also display the current settings.
 */
unsigned int get_clk_frequency_khz(int info)
{
	unsigned long cccr, turbo;
	unsigned int l, L, m, M, n2, N;

	cccr = CCCR;
	asm( "mrc\tp14, 0, %0, c6, c0, 0" : "=r" (turbo) );

	l  =  L_clk_mult[(cccr >> 0) & 0x1f];
	m  =  M_clk_mult[(cccr >> 5) & 0x03];
	n2 = N2_clk_mult[(cccr >> 7) & 0x07];

	L = l * BASE_CLK;
	M = m * L;
	N = n2 * M / 2;

	if(info)
	{
		L += 5000;
		printk( KERN_INFO "Memory clock: %d.%02dMHz (*%d)\n",
			L / 1000000, (L % 1000000) / 10000, l );
		M += 5000;
		printk( KERN_INFO "Run Mode clock: %d.%02dMHz (*%d)\n",
			M / 1000000, (M % 1000000) / 10000, m );
		N += 5000;
		printk( KERN_INFO "Turbo Mode clock: %d.%02dMHz (*%d.%d, %sactive)\n",
			N / 1000000, (N % 1000000) / 10000, n2 / 2, (n2 % 2) * 5,
			(turbo & 1) ? "" : "in" );
	}

	return (turbo & 1) ? (N/1000) : (M/1000);
}

EXPORT_SYMBOL(get_clk_frequency_khz);

/*
 * Return the current memory clock frequency in units of 10kHz
 */
unsigned int get_memclk_frequency_10khz(void)
{
	return L_clk_mult[(CCCR >> 0) & 0x1f] * BASE_CLK / 10000;
}

EXPORT_SYMBOL(get_memclk_frequency_10khz);

/*
 * Return the current LCD clock frequency in units of 10kHz
 */
unsigned int get_lcdclk_frequency_10khz(void)
{
	return get_memclk_frequency_10khz();
}

EXPORT_SYMBOL(get_lcdclk_frequency_10khz);