GNU Linux-libre 4.4.289-gnu1
[releases.git] / 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         {0, 0x01, 6000},
19         {0, 0x02, 200000},
20         {0, 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 int cris_freq_target(struct cpufreq_policy *policy, unsigned int state)
31 {
32         reg_config_rw_clk_ctrl clk_ctrl;
33         clk_ctrl = REG_RD(config, regi_config, rw_clk_ctrl);
34
35         local_irq_disable();
36
37         /* Even though we may be SMP they will share the same clock
38          * so all settings are made on CPU0. */
39         if (cris_freq_table[state].frequency == 200000)
40                 clk_ctrl.pll = 1;
41         else
42                 clk_ctrl.pll = 0;
43         REG_WR(config, regi_config, rw_clk_ctrl, clk_ctrl);
44
45         local_irq_enable();
46
47         return 0;
48 }
49
50 static int cris_freq_cpu_init(struct cpufreq_policy *policy)
51 {
52         return cpufreq_generic_init(policy, cris_freq_table, 1000000);
53 }
54
55 static struct cpufreq_driver cris_freq_driver = {
56         .get = cris_freq_get_cpu_frequency,
57         .verify = cpufreq_generic_frequency_table_verify,
58         .target_index = cris_freq_target,
59         .init = cris_freq_cpu_init,
60         .name = "cris_freq",
61         .attr = cpufreq_generic_attr,
62 };
63
64 static int __init cris_freq_init(void)
65 {
66         int ret;
67         ret = cpufreq_register_driver(&cris_freq_driver);
68         cpufreq_register_notifier(&cris_sdram_freq_notifier_block,
69                                   CPUFREQ_TRANSITION_NOTIFIER);
70         return ret;
71 }
72
73 static int
74 cris_sdram_freq_notifier(struct notifier_block *nb, unsigned long val,
75                          void *data)
76 {
77         int i;
78         struct cpufreq_freqs *freqs = data;
79         if (val == CPUFREQ_PRECHANGE) {
80                 reg_bif_core_rw_sdram_timing timing =
81                     REG_RD(bif_core, regi_bif_core, rw_sdram_timing);
82                 timing.cpd = (freqs->new == 200000 ? 0 : 1);
83
84                 if (freqs->new == 200000)
85                         for (i = 0; i < 50000; i++) ;
86                 REG_WR(bif_core, regi_bif_core, rw_sdram_timing, timing);
87         }
88         return 0;
89 }
90
91 module_init(cris_freq_init);