drivers/cpufreq/cris-artpec3-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 int cris_freq_target(struct cpufreq_policy *policy, unsigned int state)
  31 {
  32         struct cpufreq_freqs freqs;
  33         reg_clkgen_rw_clk_ctrl clk_ctrl;
  34         clk_ctrl = REG_RD(clkgen, regi_clkgen, rw_clk_ctrl);
  35
  36         freqs.old = cris_freq_get_cpu_frequency(policy->cpu);
  37         freqs.new = cris_freq_table[state].frequency;
  38
  39         cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
  40
  41         local_irq_disable();
  42
  43         /* Even though we may be SMP they will share the same clock
  44          * so all settings are made on CPU0. */
  45         if (cris_freq_table[state].frequency == 200000)
  46                 clk_ctrl.pll = 1;
  47         else
  48                 clk_ctrl.pll = 0;
  49         REG_WR(clkgen, regi_clkgen, rw_clk_ctrl, clk_ctrl);
  50
  51         local_irq_enable();
  52
  53         cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
  54
  55         return 0;
  56 }
  57
  58 static int cris_freq_cpu_init(struct cpufreq_policy *policy)
  59 {
  60         return cpufreq_generic_init(policy, cris_freq_table, 1000000);
  61 }
  62
  63 static struct cpufreq_driver cris_freq_driver = {
  64         .get    = cris_freq_get_cpu_frequency,
  65         .verify = cpufreq_generic_frequency_table_verify,
  66         .target_index = cris_freq_target,
  67         .init   = cris_freq_cpu_init,
  68         .exit   = cpufreq_generic_exit,
  69         .name   = "cris_freq",
  70         .attr   = cpufreq_generic_attr,
  71 };
  72
  73 static int __init cris_freq_init(void)
  74 {
  75         int ret;
  76         ret = cpufreq_register_driver(&cris_freq_driver);
  77         cpufreq_register_notifier(&cris_sdram_freq_notifier_block,
  78                 CPUFREQ_TRANSITION_NOTIFIER);
  79         return ret;
  80 }
  81
  82 static int
  83 cris_sdram_freq_notifier(struct notifier_block *nb, unsigned long val,
  84         void *data)
  85 {
  86         int i;
  87         struct cpufreq_freqs *freqs = data;
  88         if (val == CPUFREQ_PRECHANGE) {
  89                 reg_ddr2_rw_cfg cfg =
  90                   REG_RD(ddr2, regi_ddr2_ctrl, rw_cfg);
  91                 cfg.ref_interval = (freqs->new == 200000 ? 1560 : 46);
  92
  93                 if (freqs->new == 200000)
  94                         for (i = 0; i < 50000; i++);
  95                 REG_WR(bif_core, regi_bif_core, rw_sdram_timing, timing);
  96         }
  97         return 0;
  98 }
  99
 100
 101 module_init(cris_freq_init);