/arch/arm/mach-pxa/pxa25x.c

  1/*
  2 *  linux/arch/arm/mach-pxa/pxa25x.c
  3 *
  4 *  Author:	Nicolas Pitre
  5 *  Created:	Jun 15, 2001
  6 *  Copyright:	MontaVista Software Inc.
  7 *
  8 * Code specific to PXA21x/25x/26x variants.
  9 *
 10 * This program is free software; you can redistribute it and/or modify
 11 * it under the terms of the GNU General Public License version 2 as
 12 * published by the Free Software Foundation.
 13 *
 14 * Since this file should be linked before any other machine specific file,
 15 * the __initcall() here will be executed first.  This serves as default
 16 * initialization stuff for PXA machines which can be overridden later if
 17 * need be.
 18 */
 19#include <linux/module.h>
 20#include <linux/kernel.h>
 21#include <linux/init.h>
 22#include <linux/pm.h>
 23
 24#include <asm/hardware.h>
 25#include <asm/arch/pxa-regs.h>
 26
 27#include "generic.h"
 28
 29/*
 30 * Various clock factors driven by the CCCR register.
 31 */
 32
 33/* Crystal Frequency to Memory Frequency Multiplier (L) */
 34static unsigned char L_clk_mult[32] = { 0, 27, 32, 36, 40, 45, 0, };
 35
 36/* Memory Frequency to Run Mode Frequency Multiplier (M) */
 37static unsigned char M_clk_mult[4] = { 0, 1, 2, 4 };
 38
 39/* Run Mode Frequency to Turbo Mode Frequency Multiplier (N) */
 40/* Note: we store the value N * 2 here. */
 41static unsigned char N2_clk_mult[8] = { 0, 0, 2, 3, 4, 0, 6, 0 };
 42
 43/* Crystal clock */
 44#define BASE_CLK	3686400
 45
 46/*
 47 * Get the clock frequency as reflected by CCCR and the turbo flag.
 48 * We assume these values have been applied via a fcs.
 49 * If info is not 0 we also display the current settings.
 50 */
 51unsigned int get_clk_frequency_khz(int info)
 52{
 53	unsigned long cccr, turbo;
 54	unsigned int l, L, m, M, n2, N;
 55
 56	cccr = CCCR;
 57	asm( "mrc\tp14, 0, %0, c6, c0, 0" : "=r" (turbo) );
 58
 59	l  =  L_clk_mult[(cccr >> 0) & 0x1f];
 60	m  =  M_clk_mult[(cccr >> 5) & 0x03];
 61	n2 = N2_clk_mult[(cccr >> 7) & 0x07];
 62
 63	L = l * BASE_CLK;
 64	M = m * L;
 65	N = n2 * M / 2;
 66
 67	if(info)
 68	{
 69		L += 5000;
 70		printk( KERN_INFO "Memory clock: %d.%02dMHz (*%d)\n",
 71			L / 1000000, (L % 1000000) / 10000, l );
 72		M += 5000;
 73		printk( KERN_INFO "Run Mode clock: %d.%02dMHz (*%d)\n",
 74			M / 1000000, (M % 1000000) / 10000, m );
 75		N += 5000;
 76		printk( KERN_INFO "Turbo Mode clock: %d.%02dMHz (*%d.%d, %sactive)\n",
 77			N / 1000000, (N % 1000000) / 10000, n2 / 2, (n2 % 2) * 5,
 78			(turbo & 1) ? "" : "in" );
 79	}
 80
 81	return (turbo & 1) ? (N/1000) : (M/1000);
 82}
 83
 84EXPORT_SYMBOL(get_clk_frequency_khz);
 85
 86/*
 87 * Return the current memory clock frequency in units of 10kHz
 88 */
 89unsigned int get_memclk_frequency_10khz(void)
 90{
 91	return L_clk_mult[(CCCR >> 0) & 0x1f] * BASE_CLK / 10000;
 92}
 93
 94EXPORT_SYMBOL(get_memclk_frequency_10khz);
 95
 96/*
 97 * Return the current LCD clock frequency in units of 10kHz
 98 */
 99unsigned int get_lcdclk_frequency_10khz(void)
100{
101	return get_memclk_frequency_10khz();
102}
103
104EXPORT_SYMBOL(get_lcdclk_frequency_10khz);