release/src-rt-6.x.4708/linux/linux-2.6.36/arch/cris/arch-v32/mach-a3/cpufreq.c

   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
   9 static int
  10 cris_sdram_freq_notifier(struct notifier_block *nb, unsigned long val,
  11         void *data);
  12
  13 static struct notifier_block cris_sdram_freq_notifier_block = {
  14         .notifier_call = cris_sdram_freq_notifier
  15 };
  16
  17 static struct cpufreq_frequency_table cris_freq_table[] = {
  18         {0x01,  6000},
  19         {0x02,  200000},
  20         {0,     CPUFREQ_TABLE_END},
  21 };
  22
  23 static 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
  30 static void cris_freq_set_cpu_state(unsigned int state)
  31 {
  32         int i = 0;
  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 #ifdef CONFIG_SMP
  38         for_each_present_cpu(i)
  39 #endif
  40         {
  41                 freqs.old = cris_freq_get_cpu_frequency(i);
  42                 freqs.new = cris_freq_table[state].frequency;
  43                 freqs.cpu = i;
  44         }
  45
  46         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
  47
  48         local_irq_disable();
  49
  50         /* Even though we may be SMP they will share the same clock
  51          * so all settings are made on CPU0. */
  52         if (cris_freq_table[state].frequency == 200000)
  53                 clk_ctrl.pll = 1;
  54         else
  55                 clk_ctrl.pll = 0;
  56         REG_WR(clkgen, regi_clkgen, rw_clk_ctrl, clk_ctrl);
  57
  58         local_irq_enable();
  59
  60         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
  61 };
  62
  63 static int cris_freq_verify(struct cpufreq_policy *policy)
  64 {
  65         return cpufreq_frequency_table_verify(policy, &cris_freq_table[0]);
  66 }
  67
  68 static int cris_freq_target(struct cpufreq_policy *policy,
  69                             unsigned int target_freq,
  70                             unsigned int relation)
  71 {
  72         unsigned int newstate = 0;
  73
  74         if (cpufreq_frequency_table_target(policy, cris_freq_table,
  75                         target_freq, relation, &newstate))
  76                 return -EINVAL;
  77
  78         cris_freq_set_cpu_state(newstate);
  79
  80         return 0;
  81 }
  82
  83 static int cris_freq_cpu_init(struct cpufreq_policy *policy)
  84 {
  85         int result;
  86
  87         /* cpuinfo and default policy values */
  88         policy->cpuinfo.transition_latency = 1000000; /* 1ms */
  89         policy->cur = cris_freq_get_cpu_frequency(0);
  90
  91         result = cpufreq_frequency_table_cpuinfo(policy, cris_freq_table);
  92         if (result)
  93                 return (result);
  94
  95         cpufreq_frequency_table_get_attr(cris_freq_table, policy->cpu);
  96
  97         return 0;
  98 }
  99
 100
 101 static int cris_freq_cpu_exit(struct cpufreq_policy *policy)
 102 {
 103         cpufreq_frequency_table_put_attr(policy->cpu);
 104         return 0;
 105 }
 106
 107
 108 static struct freq_attr *cris_freq_attr[] = {
 109         &cpufreq_freq_attr_scaling_available_freqs,
 110         NULL,
 111 };
 112
 113 static struct cpufreq_driver cris_freq_driver = {
 114         .get    = cris_freq_get_cpu_frequency,
 115         .verify = cris_freq_verify,
 116         .target = cris_freq_target,
 117         .init   = cris_freq_cpu_init,
 118         .exit   = cris_freq_cpu_exit,
 119         .name   = "cris_freq",
 120         .owner  = THIS_MODULE,
 121         .attr   = cris_freq_attr,
 122 };
 123
 124 static int __init cris_freq_init(void)
 125 {
 126         int ret;
 127         ret = cpufreq_register_driver(&cris_freq_driver);
 128         cpufreq_register_notifier(&cris_sdram_freq_notifier_block,
 129                 CPUFREQ_TRANSITION_NOTIFIER);
 130         return ret;
 131 }
 132
 133 static int
 134 cris_sdram_freq_notifier(struct notifier_block *nb, unsigned long val,
 135         void *data)
 136 {
 137         int i;
 138         struct cpufreq_freqs *freqs = data;
 139         if (val == CPUFREQ_PRECHANGE) {
 140                 reg_ddr2_rw_cfg cfg =
 141                   REG_RD(ddr2, regi_ddr2_ctrl, rw_cfg);
 142                 cfg.ref_interval = (freqs->new == 200000 ? 1560 : 46);
 143
 144                 if (freqs->new == 200000)
 145                         for (i = 0; i < 50000; i++);
 146                 REG_WR(bif_core, regi_bif_core, rw_sdram_timing, timing);
 147         }
 148         return 0;
 149 }
 150
 151
 152 module_init(cris_freq_init);