2 * linux/arch/arm/mach-pxa/pxa25x.c
4 * Author: Nicolas Pitre
5 * Created: Jun 15, 2001
6 * Copyright: MontaVista Software Inc.
8 * Code specific to PXA21x/25x/26x variants.
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.
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
19 #include <linux/module.h>
20 #include <linux/kernel.h>
21 #include <linux/init.h>
24 #include <asm/hardware.h>
29 * Various clock factors driven by the CCCR register.
32 /* Crystal Frequency to Memory Frequency Multiplier (L) */
33 static unsigned char L_clk_mult[32] = { 0, 27, 32, 36, 40, 45, 0, };
35 /* Memory Frequency to Run Mode Frequency Multiplier (M) */
36 static unsigned char M_clk_mult[4] = { 0, 1, 2, 4 };
38 /* Run Mode Frequency to Turbo Mode Frequency Multiplier (N) */
39 /* Note: we store the value N * 2 here. */
40 static unsigned char N2_clk_mult[8] = { 0, 0, 2, 3, 4, 0, 6, 0 };
43 #define BASE_CLK 3686400
46 * Get the clock frequency as reflected by CCCR and the turbo flag.
47 * We assume these values have been applied via a fcs.
48 * If info is not 0 we also display the current settings.
50 unsigned int get_clk_frequency_khz(int info)
52 unsigned long cccr, turbo;
53 unsigned int l, L, m, M, n2, N;
56 asm( "mrc\tp14, 0, %0, c6, c0, 0" : "=r" (turbo) );
58 l = L_clk_mult[(cccr >> 0) & 0x1f];
59 m = M_clk_mult[(cccr >> 5) & 0x03];
60 n2 = N2_clk_mult[(cccr >> 7) & 0x07];
69 printk( KERN_INFO "Memory clock: %d.%02dMHz (*%d)\n",
70 L / 1000000, (L % 1000000) / 10000, l );
72 printk( KERN_INFO "Run Mode clock: %d.%02dMHz (*%d)\n",
73 M / 1000000, (M % 1000000) / 10000, m );
75 printk( KERN_INFO "Turbo Mode clock: %d.%02dMHz (*%d.%d, %sactive)\n",
76 N / 1000000, (N % 1000000) / 10000, n2 / 2, (n2 % 2) * 5,
77 (turbo & 1) ? "" : "in" );
80 return (turbo & 1) ? (N/1000) : (M/1000);
83 EXPORT_SYMBOL(get_clk_frequency_khz);
86 * Return the current lclk requency in units of 10kHz
88 unsigned int get_lclk_frequency_10khz(void)
90 return L_clk_mult[(CCCR >> 0) & 0x1f] * BASE_CLK / 10000;
93 EXPORT_SYMBOL(get_lclk_frequency_10khz);