linux/drivers/cpufreq/cris-etraxfs-cpufreq.c
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   1#include <linux/init.h>
   2#include <linux/module.h>
   3#include <linux/cpufreq.h>
   4#include <hwregs/reg_map.h>
   5#include <arch/hwregs/reg_rdwr.h>
   6#include <arch/hwregs/config_defs.h>
   7#include <arch/hwregs/bif_core_defs.h>
   8
   9static int
  10cris_sdram_freq_notifier(struct notifier_block *nb, unsigned long val,
  11                         void *data);
  12
  13static struct notifier_block cris_sdram_freq_notifier_block = {
  14        .notifier_call = cris_sdram_freq_notifier
  15};
  16
  17static struct cpufreq_frequency_table cris_freq_table[] = {
  18        {0x01, 6000},
  19        {0x02, 200000},
  20        {0, CPUFREQ_TABLE_END},
  21};
  22
  23static unsigned int cris_freq_get_cpu_frequency(unsigned int cpu)
  24{
  25        reg_config_rw_clk_ctrl clk_ctrl;
  26        clk_ctrl = REG_RD(config, regi_config, rw_clk_ctrl);
  27        return clk_ctrl.pll ? 200000 : 6000;
  28}
  29
  30static void cris_freq_set_cpu_state(struct cpufreq_policy *policy,
  31                unsigned int state)
  32{
  33        struct cpufreq_freqs freqs;
  34        reg_config_rw_clk_ctrl clk_ctrl;
  35        clk_ctrl = REG_RD(config, regi_config, rw_clk_ctrl);
  36
  37        freqs.old = cris_freq_get_cpu_frequency(policy->cpu);
  38        freqs.new = cris_freq_table[state].frequency;
  39
  40        cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
  41
  42        local_irq_disable();
  43
  44        /* Even though we may be SMP they will share the same clock
  45         * so all settings are made on CPU0. */
  46        if (cris_freq_table[state].frequency == 200000)
  47                clk_ctrl.pll = 1;
  48        else
  49                clk_ctrl.pll = 0;
  50        REG_WR(config, regi_config, rw_clk_ctrl, clk_ctrl);
  51
  52        local_irq_enable();
  53
  54        cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
  55};
  56
  57static int cris_freq_verify(struct cpufreq_policy *policy)
  58{
  59        return cpufreq_frequency_table_verify(policy, &cris_freq_table[0]);
  60}
  61
  62static int cris_freq_target(struct cpufreq_policy *policy,
  63                            unsigned int target_freq, unsigned int relation)
  64{
  65        unsigned int newstate = 0;
  66
  67        if (cpufreq_frequency_table_target
  68            (policy, cris_freq_table, target_freq, relation, &newstate))
  69                return -EINVAL;
  70
  71        cris_freq_set_cpu_state(policy, newstate);
  72
  73        return 0;
  74}
  75
  76static int cris_freq_cpu_init(struct cpufreq_policy *policy)
  77{
  78        int result;
  79
  80        /* cpuinfo and default policy values */
  81        policy->cpuinfo.transition_latency = 1000000;   /* 1ms */
  82        policy->cur = cris_freq_get_cpu_frequency(0);
  83
  84        result = cpufreq_frequency_table_cpuinfo(policy, cris_freq_table);
  85        if (result)
  86                return (result);
  87
  88        cpufreq_frequency_table_get_attr(cris_freq_table, policy->cpu);
  89
  90        return 0;
  91}
  92
  93static int cris_freq_cpu_exit(struct cpufreq_policy *policy)
  94{
  95        cpufreq_frequency_table_put_attr(policy->cpu);
  96        return 0;
  97}
  98
  99static struct freq_attr *cris_freq_attr[] = {
 100        &cpufreq_freq_attr_scaling_available_freqs,
 101        NULL,
 102};
 103
 104static struct cpufreq_driver cris_freq_driver = {
 105        .get = cris_freq_get_cpu_frequency,
 106        .verify = cris_freq_verify,
 107        .target = cris_freq_target,
 108        .init = cris_freq_cpu_init,
 109        .exit = cris_freq_cpu_exit,
 110        .name = "cris_freq",
 111        .owner = THIS_MODULE,
 112        .attr = cris_freq_attr,
 113};
 114
 115static int __init cris_freq_init(void)
 116{
 117        int ret;
 118        ret = cpufreq_register_driver(&cris_freq_driver);
 119        cpufreq_register_notifier(&cris_sdram_freq_notifier_block,
 120                                  CPUFREQ_TRANSITION_NOTIFIER);
 121        return ret;
 122}
 123
 124static int
 125cris_sdram_freq_notifier(struct notifier_block *nb, unsigned long val,
 126                         void *data)
 127{
 128        int i;
 129        struct cpufreq_freqs *freqs = data;
 130        if (val == CPUFREQ_PRECHANGE) {
 131                reg_bif_core_rw_sdram_timing timing =
 132                    REG_RD(bif_core, regi_bif_core, rw_sdram_timing);
 133                timing.cpd = (freqs->new == 200000 ? 0 : 1);
 134
 135                if (freqs->new == 200000)
 136                        for (i = 0; i < 50000; i++) ;
 137                REG_WR(bif_core, regi_bif_core, rw_sdram_timing, timing);
 138        }
 139        return 0;
 140}
 141
 142module_init(cris_freq_init);
 143
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