release/src-rt-6.x.4708/linux/linux-2.6.36/arch/cris/arch-v32/mach-fs/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 <arch/hwregs/reg_rdwr.h>
   6 #include <arch/hwregs/config_defs.h>
   7 #include <arch/hwregs/bif_core_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_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
  30 static void cris_freq_set_cpu_state(unsigned int state)
  31 {
  32         int i;
  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         for_each_possible_cpu(i) {
  38                 freqs.old = cris_freq_get_cpu_frequency(i);
  39                 freqs.new = cris_freq_table[state].frequency;
  40                 freqs.cpu = i;
  41         }
  42
  43         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
  44
  45         local_irq_disable();
  46
  47         /* Even though we may be SMP they will share the same clock
  48          * so all settings are made on CPU0. */
  49         if (cris_freq_table[state].frequency == 200000)
  50                 clk_ctrl.pll = 1;
  51         else
  52                 clk_ctrl.pll = 0;
  53         REG_WR(config, regi_config, rw_clk_ctrl, clk_ctrl);
  54
  55         local_irq_enable();
  56
  57         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
  58 };
  59
  60 static int cris_freq_verify(struct cpufreq_policy *policy)
  61 {
  62         return cpufreq_frequency_table_verify(policy, &cris_freq_table[0]);
  63 }
  64
  65 static int cris_freq_target(struct cpufreq_policy *policy,
  66                             unsigned int target_freq, unsigned int relation)
  67 {
  68         unsigned int newstate = 0;
  69
  70         if (cpufreq_frequency_table_target
  71             (policy, cris_freq_table, target_freq, relation, &newstate))
  72                 return -EINVAL;
  73
  74         cris_freq_set_cpu_state(newstate);
  75
  76         return 0;
  77 }
  78
  79 static int cris_freq_cpu_init(struct cpufreq_policy *policy)
  80 {
  81         int result;
  82
  83         /* cpuinfo and default policy values */
  84         policy->cpuinfo.transition_latency = 1000000;   /* 1ms */
  85         policy->cur = cris_freq_get_cpu_frequency(0);
  86
  87         result = cpufreq_frequency_table_cpuinfo(policy, cris_freq_table);
  88         if (result)
  89                 return (result);
  90
  91         cpufreq_frequency_table_get_attr(cris_freq_table, policy->cpu);
  92
  93         return 0;
  94 }
  95
  96 static int cris_freq_cpu_exit(struct cpufreq_policy *policy)
  97 {
  98         cpufreq_frequency_table_put_attr(policy->cpu);
  99         return 0;
 100 }
 101
 102 static struct freq_attr *cris_freq_attr[] = {
 103         &cpufreq_freq_attr_scaling_available_freqs,
 104         NULL,
 105 };
 106
 107 static 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
 118 static 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
 127 static int
 128 cris_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_bif_core_rw_sdram_timing timing =
 135                     REG_RD(bif_core, regi_bif_core, rw_sdram_timing);
 136                 timing.cpd = (freqs->new == 200000 ? 0 : 1);
 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 module_init(cris_freq_init);