linux/drivers/cpufreq/cris-artpec3-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 <hwregs/reg_rdwr.h>
   6#include <hwregs/clkgen_defs.h>
   7#include <hwregs/ddr2_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_clkgen_rw_clk_ctrl clk_ctrl;
  26        clk_ctrl = REG_RD(clkgen, regi_clkgen, 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_clkgen_rw_clk_ctrl clk_ctrl;
  35        clk_ctrl = REG_RD(clkgen, regi_clkgen, 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(clkgen, regi_clkgen, 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,
  64                            unsigned int relation)
  65{
  66        unsigned int newstate = 0;
  67
  68        if (cpufreq_frequency_table_target(policy, cris_freq_table,
  69                        target_freq, relation, &newstate))
  70                return -EINVAL;
  71
  72        cris_freq_set_cpu_state(policy, newstate);
  73
  74        return 0;
  75}
  76
  77static int cris_freq_cpu_init(struct cpufreq_policy *policy)
  78{
  79        int result;
  80
  81        /* cpuinfo and default policy values */
  82        policy->cpuinfo.transition_latency = 1000000; /* 1ms */
  83        policy->cur = cris_freq_get_cpu_frequency(0);
  84
  85        result = cpufreq_frequency_table_cpuinfo(policy, cris_freq_table);
  86        if (result)
  87                return (result);
  88
  89        cpufreq_frequency_table_get_attr(cris_freq_table, policy->cpu);
  90
  91        return 0;
  92}
  93
  94
  95static int cris_freq_cpu_exit(struct cpufreq_policy *policy)
  96{
  97        cpufreq_frequency_table_put_attr(policy->cpu);
  98        return 0;
  99}
 100
 101
 102static struct freq_attr *cris_freq_attr[] = {
 103        &cpufreq_freq_attr_scaling_available_freqs,
 104        NULL,
 105};
 106
 107static struct cpufreq_driver cris_freq_driver = {
 108        .get    = cris_freq_get_cpu_frequency,
 109        .verify = cris_freq_verify,
 110        .target = cris_freq_target,
 111        .init   = cris_freq_cpu_init,
 112        .exit   = cris_freq_cpu_exit,
 113        .name   = "cris_freq",
 114        .owner  = THIS_MODULE,
 115        .attr   = cris_freq_attr,
 116};
 117
 118static int __init cris_freq_init(void)
 119{
 120        int ret;
 121        ret = cpufreq_register_driver(&cris_freq_driver);
 122        cpufreq_register_notifier(&cris_sdram_freq_notifier_block,
 123                CPUFREQ_TRANSITION_NOTIFIER);
 124        return ret;
 125}
 126
 127static int
 128cris_sdram_freq_notifier(struct notifier_block *nb, unsigned long val,
 129        void *data)
 130{
 131        int i;
 132        struct cpufreq_freqs *freqs = data;
 133        if (val == CPUFREQ_PRECHANGE) {
 134                reg_ddr2_rw_cfg cfg =
 135                  REG_RD(ddr2, regi_ddr2_ctrl, rw_cfg);
 136                cfg.ref_interval = (freqs->new == 200000 ? 1560 : 46);
 137
 138                if (freqs->new == 200000)
 139                        for (i = 0; i < 50000; i++);
 140                REG_WR(bif_core, regi_bif_core, rw_sdram_timing, timing);
 141        }
 142        return 0;
 143}
 144
 145
 146module_init(cris_freq_init);
 147
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