pxa27x.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 120 行

/*
 *  linux/arch/arm/mach-pxa/pxa27x.c
 *
 *  Author:	Nicolas Pitre
 *  Created:	Nov 05, 2002
 *  Copyright:	MontaVista Software Inc.
 *
 * Code specific to PXA27x aka Bulverde.
 *
 * 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 <linux/config.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <asm/arch/pxa-regs.h>
#include <linux/init.h>
#include <linux/pm.h>

#include <asm/hardware.h>

#include "generic.h"

/* Crystal clock: 13MHz */
#define BASE_CLK	13000000

/*
 * Get the clock frequency as reflected by CCSR 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 ccsr, clkcfg;
	unsigned int l, L, m, M, n2, N, S;
       	int cccr_a, t, ht, b;

	ccsr = CCSR;
	cccr_a = CCCR & (1 << 25);

	/* Read clkcfg register: it has turbo, b, half-turbo (and f) */
	asm( "mrc\tp14, 0, %0, c6, c0, 0" : "=r" (clkcfg) );
	t  = clkcfg & (1 << 1);
	ht = clkcfg & (1 << 2);
	b  = clkcfg & (1 << 3);

	l  = ccsr & 0x1f;
	n2 = (ccsr>>7) & 0xf;
	m  = (l <= 10) ? 1 : (l <= 20) ? 2 : 4;

	L  = l * BASE_CLK;
	N  = (L * n2) / 2;
	M  = (!cccr_a) ? (L/m) : ((b) ? L : (L/2));
	S  = (b) ? L : (L/2);

	if (info) {
		printk( KERN_INFO "Run Mode clock: %d.%02dMHz (*%d)\n",
			L / 1000000, (L % 1000000) / 10000, l );
		printk( KERN_INFO "Turbo Mode clock: %d.%02dMHz (*%d.%d, %sactive)\n",
			N / 1000000, (N % 1000000)/10000, n2 / 2, (n2 % 2)*5,
			(t) ? "" : "in" );
		printk( KERN_INFO "Memory clock: %d.%02dMHz (/%d)\n",
			M / 1000000, (M % 1000000) / 10000, m );
		printk( KERN_INFO "System bus clock: %d.%02dMHz \n",
			S / 1000000, (S % 1000000) / 10000 );
	}

	return (t) ? (N/1000) : (L/1000);
}

/*
 * Return the current mem clock frequency in units of 10kHz as
 * reflected by CCCR[A], B, and L
 */
unsigned int get_memclk_frequency_10khz(void)
{
	unsigned long ccsr, clkcfg;
	unsigned int l, L, m, M;
       	int cccr_a, b;

	ccsr = CCSR;
	cccr_a = CCCR & (1 << 25);

	/* Read clkcfg register: it has turbo, b, half-turbo (and f) */
	asm( "mrc\tp14, 0, %0, c6, c0, 0" : "=r" (clkcfg) );
	b = clkcfg & (1 << 3);

	l = ccsr & 0x1f;
	m = (l <= 10) ? 1 : (l <= 20) ? 2 : 4;

	L = l * BASE_CLK;
	M = (!cccr_a) ? (L/m) : ((b) ? L : (L/2));

	return (M / 10000);
}

/*
 * Return the current LCD clock frequency in units of 10kHz as
 */
unsigned int get_lcdclk_frequency_10khz(void)
{
	unsigned long ccsr;
	unsigned int l, L, k, K;

	ccsr = CCSR;

	l = ccsr & 0x1f;
	k = (l <= 7) ? 1 : (l <= 16) ? 2 : 4;

	L = l * BASE_CLK;
	K = L / k;

	return (K / 10000);
}

EXPORT_SYMBOL(get_clk_frequency_khz);
EXPORT_SYMBOL(get_memclk_frequency_10khz);
EXPORT_SYMBOL(get_lcdclk_frequency_10khz);