cris-artpec3-cpufreq.c revision 979d86fac5e6dbf5c939e9a2a9fe294c9e05e42f 
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
9static int
10cris_sdram_freq_notifier(struct notifier_block *nb, unsigned long val,
11	void *data);
12
13static struct notifier_block cris_sdram_freq_notifier_block = {
14	.notifier_call = cris_sdram_freq_notifier
15};
16
17static struct cpufreq_frequency_table cris_freq_table[] = {
18	{0x01,	6000},
19	{0x02,	200000},
20	{0,	CPUFREQ_TABLE_END},
21};
22
23static 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
30static int cris_freq_target(struct cpufreq_policy *policy, unsigned int state)
31{
32	reg_clkgen_rw_clk_ctrl clk_ctrl;
33	clk_ctrl = REG_RD(clkgen, regi_clkgen, 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(clkgen, regi_clkgen, rw_clk_ctrl, clk_ctrl);
44
45	local_irq_enable();
46
47	return 0;
48}
49
50static int cris_freq_cpu_init(struct cpufreq_policy *policy)
51{
52	return cpufreq_generic_init(policy, cris_freq_table, 1000000);
53}
54
55static 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
64static 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
73static int
74cris_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_ddr2_rw_cfg cfg =
81		  REG_RD(ddr2, regi_ddr2_ctrl, rw_cfg);
82		cfg.ref_interval = (freqs->new == 200000 ? 1560 : 46);
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
92module_init(cris_freq_init);
93