arch/arm/mach-s3c2410/cpu-freq.c

   1 /* linux/arch/arm/mach-s3c2410/cpu-freq.c
   2  *
   3  * Copyright (c) 2006,2008 Simtec Electronics
   4  *      http://armlinux.simtec.co.uk/
   5  *      Ben Dooks <ben@simtec.co.uk>
   6  *
   7  * S3C2410 CPU Frequency scaling
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12 */
  13
  14 #include <linux/init.h>
  15 #include <linux/module.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/ioport.h>
  18 #include <linux/cpufreq.h>
  19 #include <linux/sysdev.h>
  20 #include <linux/clk.h>
  21 #include <linux/err.h>
  22 #include <linux/io.h>
  23
  24 #include <asm/mach/arch.h>
  25 #include <asm/mach/map.h>
  26
  27 #include <mach/regs-clock.h>
  28
  29 #include <plat/cpu.h>
  30 #include <plat/clock.h>
  31 #include <plat/cpu-freq-core.h>
  32
  33 /* Note, 2410A has an extra mode for 1:4:4 ratio, bit 2 of CLKDIV */
  34
  35 static void s3c2410_cpufreq_setdivs(struct s3c_cpufreq_config *cfg)
  36 {
  37         u32 clkdiv = 0;
  38
  39         if (cfg->divs.h_divisor == 2)
  40                 clkdiv |= S3C2410_CLKDIVN_HDIVN;
  41
  42         if (cfg->divs.p_divisor != cfg->divs.h_divisor)
  43                 clkdiv |= S3C2410_CLKDIVN_PDIVN;
  44
  45         __raw_writel(clkdiv, S3C2410_CLKDIVN);
  46 }
  47
  48 static int s3c2410_cpufreq_calcdivs(struct s3c_cpufreq_config *cfg)
  49 {
  50         unsigned long hclk, fclk, pclk;
  51         unsigned int hdiv, pdiv;
  52         unsigned long hclk_max;
  53
  54         fclk = cfg->freq.fclk;
  55         hclk_max = cfg->max.hclk;
  56
  57         cfg->freq.armclk = fclk;
  58
  59         s3c_freq_dbg("%s: fclk is %lu, max hclk %lu\n",
  60                       __func__, fclk, hclk_max);
  61
  62         hdiv = (fclk > cfg->max.hclk) ? 2 : 1;
  63         hclk = fclk / hdiv;
  64
  65         if (hclk > cfg->max.hclk) {
  66                 s3c_freq_dbg("%s: hclk too big\n", __func__);
  67                 return -EINVAL;
  68         }
  69
  70         pdiv = (hclk > cfg->max.pclk) ? 2 : 1;
  71         pclk = hclk / pdiv;
  72
  73         if (pclk > cfg->max.pclk) {
  74                 s3c_freq_dbg("%s: pclk too big\n", __func__);
  75                 return -EINVAL;
  76         }
  77
  78         pdiv *= hdiv;
  79
  80         /* record the result */
  81         cfg->divs.p_divisor = pdiv;
  82         cfg->divs.h_divisor = hdiv;
  83
  84         return 0      ;
  85 }
  86
  87 static struct s3c_cpufreq_info s3c2410_cpufreq_info = {
  88         .max            = {
  89                 .fclk   = 200000000,
  90                 .hclk   = 100000000,
  91                 .pclk   =  50000000,
  92         },
  93
  94         /* transition latency is about 5ms worst-case, so
  95          * set 10ms to be sure */
  96         .latency        = 10000000,
  97
  98         .locktime_m     = 150,
  99         .locktime_u     = 150,
 100         .locktime_bits  = 12,
 101
 102         .need_pll       = 1,
 103
 104         .name           = "s3c2410",
 105         .calc_iotiming  = s3c2410_iotiming_calc,
 106         .set_iotiming   = s3c2410_iotiming_set,
 107         .get_iotiming   = s3c2410_iotiming_get,
 108         .resume_clocks  = s3c2410_setup_clocks,
 109
 110         .set_fvco       = s3c2410_set_fvco,
 111         .set_refresh    = s3c2410_cpufreq_setrefresh,
 112         .set_divs       = s3c2410_cpufreq_setdivs,
 113         .calc_divs      = s3c2410_cpufreq_calcdivs,
 114
 115         .debug_io_show  = s3c_cpufreq_debugfs_call(s3c2410_iotiming_debugfs),
 116 };
 117
 118 static int s3c2410_cpufreq_add(struct sys_device *sysdev)
 119 {
 120         return s3c_cpufreq_register(&s3c2410_cpufreq_info);
 121 }
 122
 123 static struct sysdev_driver s3c2410_cpufreq_driver = {
 124         .add            = s3c2410_cpufreq_add,
 125 };
 126
 127 static int __init s3c2410_cpufreq_init(void)
 128 {
 129         return sysdev_driver_register(&s3c2410_sysclass,
 130                                       &s3c2410_cpufreq_driver);
 131 }
 132
 133 arch_initcall(s3c2410_cpufreq_init);
 134
 135 static int s3c2410a_cpufreq_add(struct sys_device *sysdev)
 136 {
 137         /* alter the maximum freq settings for S3C2410A. If a board knows
 138          * it only has a maximum of 200, then it should register its own
 139          * limits. */
 140
 141         s3c2410_cpufreq_info.max.fclk = 266000000;
 142         s3c2410_cpufreq_info.max.hclk = 133000000;
 143         s3c2410_cpufreq_info.max.pclk =  66500000;
 144         s3c2410_cpufreq_info.name = "s3c2410a";
 145
 146         return s3c2410_cpufreq_add(sysdev);
 147 }
 148
 149 static struct sysdev_driver s3c2410a_cpufreq_driver = {
 150         .add            = s3c2410a_cpufreq_add,
 151 };
 152
 153 static int __init s3c2410a_cpufreq_init(void)
 154 {
 155         return sysdev_driver_register(&s3c2410a_sysclass,
 156                                       &s3c2410a_cpufreq_driver);
 157 }
 158
 159 arch_initcall(s3c2410a_cpufreq_init);