arch/arm/mach-s3c24a0/clocks.c

   1 /*
   2  *  arch/arm/mach-s3c24a0/clocks.c
   3  *
   4  *  $Id: clocks.c,v 1.3 2006/12/12 13:38:48 gerg Exp $
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License version 2 as
   8  *  published by the Free Software Foundation.
   9  *
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/init.h>
  14 #include <linux/module.h>
  15
  16 #include <asm/errno.h>
  17 #include <asm/arch/clocks.h>
  18
  19
  20
  21 static unsigned long get_usb_clk_freq(int who)
  22 {
  23         unsigned long val = UPLLCON;
  24
  25         if (CLKSRC & (1<<7)) return 0;  /* UPLL OFF */
  26         val = ((GET_MDIV(val) + 8) * FIN)/((GET_PDIV(val) + 2) * (1 << GET_SDIV(val)));
  27         return val;
  28 }
  29
  30 /*
  31  * CLKDIVN  differs from S3C24A0X to S3C24A0A
  32  * --SW.LEE
  33  */
  34
  35 static inline unsigned long
  36 cal_bus_clk(unsigned long cpu_clk, unsigned long ratio, int who)
  37 {
  38         unsigned long hclk = 0;
  39         unsigned long pclk = 0;
  40
  41         if (who == GET_UPLL)
  42                 return get_usb_clk_freq(GET_UPLL);
  43
  44         switch (ratio & 0x6) {
  45                 case 0:
  46                         hclk = cpu_clk;
  47                         break;
  48                 case 2:
  49                         hclk = cpu_clk/2;
  50                         break;
  51                 case 4:
  52                         hclk = cpu_clk/4;
  53                         break;
  54                 default:
  55                         panic("Wrong Value in CLKDIVN");
  56         }
  57         switch (ratio & 0x1) {
  58                 case 0:
  59                         pclk = hclk;
  60                         break;
  61                 case 1:
  62                         pclk = hclk/2;
  63                         break;
  64         }
  65
  66         if (who == GET_HCLK)
  67                         return hclk;
  68         else {
  69                 if (who == GET_PCLK)
  70                         return pclk;
  71                 else
  72                         panic("Wrong Clock requested ");
  73         }
  74 }
  75
  76
  77 /*
  78  * cpu clock = (((mdiv + 8) * FIN) / ((pdiv + 2) * (1 << sdiv)))
  79  *  FIN = Input Frequency (to CPU)
  80  */
  81 unsigned long
  82 elfin_get_cpu_clk(void)
  83 {
  84         unsigned long val = MPLLCON;
  85
  86         return (((GET_MDIV(val) + 8) * FIN) / ((GET_PDIV(val) + 2) * (1 << GET_SDIV(val))));
  87 }
  88 EXPORT_SYMBOL(elfin_get_cpu_clk);
  89
  90 unsigned long
  91 elfin_get_bus_clk(int who)
  92 {
  93         unsigned long cpu_clk = elfin_get_cpu_clk();
  94         unsigned long ratio = CLKDIVN_BUS;
  95
  96         return (cal_bus_clk(cpu_clk, ratio, who));
  97 }
  98 EXPORT_SYMBOL(elfin_get_bus_clk);
  99
 100 #define MEGA    (1000 * 1000)
 101 static int __init elfin_cpu_init(void)
 102 {
 103         unsigned long freq, hclk, pclk;
 104
 105         freq = elfin_get_cpu_clk();
 106         hclk = elfin_get_bus_clk(GET_HCLK);
 107         pclk = elfin_get_bus_clk(GET_PCLK);
 108
 109         printk(KERN_INFO "CPU clock = %ld.%03ld Mhz,", freq / MEGA, freq % MEGA);
 110
 111         printk(" HCLK = %ld.%03ld Mhz, PCLK = %ld.%03ld Mhz\n",
 112                  hclk / MEGA, hclk % MEGA, pclk / MEGA, pclk % MEGA);
 113
 114         return 0;
 115 }
 116
 117 __initcall(elfin_cpu_init);