drivers/cpufreq/cris-etraxfs-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(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
  57 static int cris_freq_target(struct cpufreq_policy *policy,
  58                             unsigned int target_freq, unsigned int relation)
  59 {
  60         unsigned int newstate = 0;
  61
  62         if (cpufreq_frequency_table_target
  63             (policy, cris_freq_table, target_freq, relation, &newstate))
  64                 return -EINVAL;
  65
  66         cris_freq_set_cpu_state(policy, newstate);
  67
  68         return 0;
  69 }
  70
  71 static int cris_freq_cpu_init(struct cpufreq_policy *policy)
  72 {
  73         return cpufreq_generic_init(policy, cris_freq_table, 1000000);
  74 }
  75
  76 static struct cpufreq_driver cris_freq_driver = {
  77         .get = cris_freq_get_cpu_frequency,
  78         .verify = cpufreq_generic_frequency_table_verify,
  79         .target = cris_freq_target,
  80         .init = cris_freq_cpu_init,
  81         .exit = cpufreq_generic_exit,
  82         .name = "cris_freq",
  83         .attr = cpufreq_generic_attr,
  84 };
  85
  86 static int __init cris_freq_init(void)
  87 {
  88         int ret;
  89         ret = cpufreq_register_driver(&cris_freq_driver);
  90         cpufreq_register_notifier(&cris_sdram_freq_notifier_block,
  91                                   CPUFREQ_TRANSITION_NOTIFIER);
  92         return ret;
  93 }
  94
  95 static int
  96 cris_sdram_freq_notifier(struct notifier_block *nb, unsigned long val,
  97                          void *data)
  98 {
  99         int i;
 100         struct cpufreq_freqs *freqs = data;
 101         if (val == CPUFREQ_PRECHANGE) {
 102                 reg_bif_core_rw_sdram_timing timing =
 103                     REG_RD(bif_core, regi_bif_core, rw_sdram_timing);
 104                 timing.cpd = (freqs->new == 200000 ? 0 : 1);
 105
 106                 if (freqs->new == 200000)
 107                         for (i = 0; i < 50000; i++) ;
 108                 REG_WR(bif_core, regi_bif_core, rw_sdram_timing, timing);
 109         }
 110         return 0;
 111 }
 112
 113 module_init(cris_freq_init);