arch/blackfin/mach-bf548/cpu.c

   1 /*
   2  * File:         arch/blackfin/mach-bf548/cpu.c
   3  * Based on:
   4  * Author:
   5  *
   6  * Created:
   7  * Description:  clock scaling for the bf54x
   8  *
   9  * Modified:
  10  *               Copyright 2004-2007 Analog Devices Inc.
  11  *
  12  * Bugs:         Enter bugs at http://blackfin.uclinux.org/
  13  *
  14  * This program is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * This program is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with this program; if not, see the file COPYING, or write
  26  * to the Free Software Foundation, Inc.,
  27  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  28  */
  29
  30 #include <linux/kernel.h>
  31 #include <linux/types.h>
  32 #include <linux/init.h>
  33 #include <linux/cpufreq.h>
  34 #include <asm/dpmc.h>
  35 #include <linux/fs.h>
  36 #include <asm/bfin-global.h>
  37
  38 /* CONFIG_CLKIN_HZ=25000000 */
  39 #define VCO5 (CONFIG_CLKIN_HZ*45)
  40 #define VCO4 (CONFIG_CLKIN_HZ*36)
  41 #define VCO3 (CONFIG_CLKIN_HZ*27)
  42 #define VCO2 (CONFIG_CLKIN_HZ*18)
  43 #define VCO1 (CONFIG_CLKIN_HZ*9)
  44 #define VCO(x) VCO##x
  45
  46 #define MFREQ(x) {VCO(x),VCO(x)/4},{VCO(x),VCO(x)/2},{VCO(x),VCO(x)}
  47 /* frequency */
  48 static struct cpufreq_frequency_table bf548_freq_table[] = {
  49         MFREQ(1),
  50         MFREQ(3),
  51         {VCO4, VCO4 / 2}, {VCO4, VCO4},
  52         MFREQ(5),
  53         {0, CPUFREQ_TABLE_END},
  54 };
  55
  56 /*
  57  * dpmc_fops->ioctl()
  58  * static int dpmc_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
  59  */
  60 static int bf548_getfreq(unsigned int cpu)
  61 {
  62         unsigned long cclk_mhz;
  63
  64         /* The driver only support single cpu */
  65         if (cpu == 0)
  66                 dpmc_fops.ioctl(NULL, NULL, IOCTL_GET_CORECLOCK, &cclk_mhz);
  67         else
  68                 cclk_mhz = -1;
  69
  70         return cclk_mhz;
  71 }
  72
  73 static int bf548_target(struct cpufreq_policy *policy,
  74                             unsigned int target_freq, unsigned int relation)
  75 {
  76         unsigned long cclk_mhz;
  77         unsigned long vco_mhz;
  78         unsigned long flags;
  79         unsigned int index;
  80         struct cpufreq_freqs freqs;
  81
  82         if (cpufreq_frequency_table_target(policy, bf548_freq_table, target_freq, relation, &index))
  83                 return -EINVAL;
  84
  85         cclk_mhz = bf548_freq_table[index].frequency;
  86         vco_mhz = bf548_freq_table[index].index;
  87
  88         dpmc_fops.ioctl(NULL, NULL, IOCTL_CHANGE_FREQUENCY, &vco_mhz);
  89         freqs.old = bf548_getfreq(0);
  90         freqs.new = cclk_mhz;
  91         freqs.cpu = 0;
  92
  93         pr_debug("cclk begin change to cclk %d,vco=%d,index=%d,target=%d,oldfreq=%d\n",
  94                  cclk_mhz, vco_mhz, index, target_freq, freqs.old);
  95
  96         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
  97         local_irq_save(flags);
  98         dpmc_fops.ioctl(NULL, NULL, IOCTL_SET_CCLK, &cclk_mhz);
  99         local_irq_restore(flags);
 100         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 101
 102         vco_mhz = get_vco();
 103         cclk_mhz = get_cclk();
 104         return 0;
 105 }
 106
 107 /* make sure that only the "userspace" governor is run -- anything else wouldn't make sense on
 108  * this platform, anyway.
 109  */
 110 static int bf548_verify_speed(struct cpufreq_policy *policy)
 111 {
 112         return cpufreq_frequency_table_verify(policy, &bf548_freq_table);
 113 }
 114
 115 static int __init __bf548_cpu_init(struct cpufreq_policy *policy)
 116 {
 117         if (policy->cpu != 0)
 118                 return -EINVAL;
 119
 120         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
 121
 122         policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
 123         /*Now ,only support one cpu */
 124         policy->cur = bf548_getfreq(0);
 125         cpufreq_frequency_table_get_attr(bf548_freq_table, policy->cpu);
 126         return cpufreq_frequency_table_cpuinfo(policy, bf548_freq_table);
 127 }
 128
 129 static struct freq_attr *bf548_freq_attr[] = {
 130         &cpufreq_freq_attr_scaling_available_freqs,
 131         NULL,
 132 };
 133
 134 static struct cpufreq_driver bf548_driver = {
 135         .verify = bf548_verify_speed,
 136         .target = bf548_target,
 137         .get = bf548_getfreq,
 138         .init = __bf548_cpu_init,
 139         .name = "bf548",
 140         .owner = THIS_MODULE,
 141         .attr = bf548_freq_attr,
 142 };
 143
 144 static int __init bf548_cpu_init(void)
 145 {
 146         return cpufreq_register_driver(&bf548_driver);
 147 }
 148
 149 static void __exit bf548_cpu_exit(void)
 150 {
 151         cpufreq_unregister_driver(&bf548_driver);
 152 }
 153
 154 MODULE_AUTHOR("Mickael Kang");
 155 MODULE_DESCRIPTION("cpufreq driver for BF548 CPU");
 156 MODULE_LICENSE("GPL");
 157
 158 module_init(bf548_cpu_init);
 159 module_exit(bf548_cpu_exit);