cris-artpec3-cpufreq.c revision adc97d6a735dbb1e94cb4f1bf0b55f258b349941 
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 void cris_freq_set_cpu_state(struct cpufreq_policy *policy,
31		unsigned int state)
32{
33	struct cpufreq_freqs freqs;
34	reg_clkgen_rw_clk_ctrl clk_ctrl;
35	clk_ctrl = REG_RD(clkgen, regi_clkgen, 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(clkgen, regi_clkgen, rw_clk_ctrl, clk_ctrl);
51
52	local_irq_enable();
53
54	cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
55};
56
57static int cris_freq_verify(struct cpufreq_policy *policy)
58{
59	return cpufreq_frequency_table_verify(policy, &cris_freq_table[0]);
60}
61
62static int cris_freq_target(struct cpufreq_policy *policy,
63			    unsigned int target_freq,
64			    unsigned int relation)
65{
66	unsigned int newstate = 0;
67
68	if (cpufreq_frequency_table_target(policy, cris_freq_table,
69			target_freq, relation, &newstate))
70		return -EINVAL;
71
72	cris_freq_set_cpu_state(policy, newstate);
73
74	return 0;
75}
76
77static int cris_freq_cpu_init(struct cpufreq_policy *policy)
78{
79	int result;
80
81	/* cpuinfo and default policy values */
82	policy->cpuinfo.transition_latency = 1000000; /* 1ms */
83	policy->cur = cris_freq_get_cpu_frequency(0);
84
85	result = cpufreq_frequency_table_cpuinfo(policy, cris_freq_table);
86	if (result)
87		return (result);
88
89	cpufreq_frequency_table_get_attr(cris_freq_table, policy->cpu);
90
91	return 0;
92}
93
94
95static int cris_freq_cpu_exit(struct cpufreq_policy *policy)
96{
97	cpufreq_frequency_table_put_attr(policy->cpu);
98	return 0;
99}
100
101
102static struct freq_attr *cris_freq_attr[] = {
103	&cpufreq_freq_attr_scaling_available_freqs,
104	NULL,
105};
106
107static 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	.attr	= cris_freq_attr,
115};
116
117static int __init cris_freq_init(void)
118{
119	int ret;
120	ret = cpufreq_register_driver(&cris_freq_driver);
121	cpufreq_register_notifier(&cris_sdram_freq_notifier_block,
122		CPUFREQ_TRANSITION_NOTIFIER);
123	return ret;
124}
125
126static int
127cris_sdram_freq_notifier(struct notifier_block *nb, unsigned long val,
128	void *data)
129{
130	int i;
131	struct cpufreq_freqs *freqs = data;
132	if (val == CPUFREQ_PRECHANGE) {
133		reg_ddr2_rw_cfg cfg =
134		  REG_RD(ddr2, regi_ddr2_ctrl, rw_cfg);
135		cfg.ref_interval = (freqs->new == 200000 ? 1560 : 46);
136
137		if (freqs->new == 200000)
138			for (i = 0; i < 50000; i++);
139		REG_WR(bif_core, regi_bif_core, rw_sdram_timing, timing);
140	}
141	return 0;
142}
143
144
145module_init(cris_freq_init);
146