1cdb56cbfSMarkus Mayer /*
2cdb56cbfSMarkus Mayer * CPU frequency scaling for Broadcom BMIPS SoCs
3cdb56cbfSMarkus Mayer *
4cdb56cbfSMarkus Mayer * Copyright (c) 2017 Broadcom
5cdb56cbfSMarkus Mayer *
6cdb56cbfSMarkus Mayer * This program is free software; you can redistribute it and/or
7cdb56cbfSMarkus Mayer * modify it under the terms of the GNU General Public License as
8cdb56cbfSMarkus Mayer * published by the Free Software Foundation version 2.
9cdb56cbfSMarkus Mayer *
10cdb56cbfSMarkus Mayer * This program is distributed "as is" WITHOUT ANY WARRANTY of any
11cdb56cbfSMarkus Mayer * kind, whether express or implied; without even the implied warranty
12cdb56cbfSMarkus Mayer * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13cdb56cbfSMarkus Mayer * GNU General Public License for more details.
14cdb56cbfSMarkus Mayer */
15cdb56cbfSMarkus Mayer
16cdb56cbfSMarkus Mayer #include <linux/cpufreq.h>
17cdb56cbfSMarkus Mayer #include <linux/module.h>
18cdb56cbfSMarkus Mayer #include <linux/of_address.h>
19cdb56cbfSMarkus Mayer #include <linux/slab.h>
20cdb56cbfSMarkus Mayer
21cdb56cbfSMarkus Mayer /* for mips_hpt_frequency */
22cdb56cbfSMarkus Mayer #include <asm/time.h>
23cdb56cbfSMarkus Mayer
24cdb56cbfSMarkus Mayer #define BMIPS_CPUFREQ_PREFIX "bmips"
25cdb56cbfSMarkus Mayer #define BMIPS_CPUFREQ_NAME BMIPS_CPUFREQ_PREFIX "-cpufreq"
26cdb56cbfSMarkus Mayer
27cdb56cbfSMarkus Mayer #define TRANSITION_LATENCY (25 * 1000) /* 25 us */
28cdb56cbfSMarkus Mayer
29cdb56cbfSMarkus Mayer #define BMIPS5_CLK_DIV_SET_SHIFT 0x7
30cdb56cbfSMarkus Mayer #define BMIPS5_CLK_DIV_SHIFT 0x4
31cdb56cbfSMarkus Mayer #define BMIPS5_CLK_DIV_MASK 0xf
32cdb56cbfSMarkus Mayer
33cdb56cbfSMarkus Mayer enum bmips_type {
34cdb56cbfSMarkus Mayer BMIPS5000,
35cdb56cbfSMarkus Mayer BMIPS5200,
36cdb56cbfSMarkus Mayer };
37cdb56cbfSMarkus Mayer
38cdb56cbfSMarkus Mayer struct cpufreq_compat {
39cdb56cbfSMarkus Mayer const char *compatible;
40cdb56cbfSMarkus Mayer unsigned int bmips_type;
41cdb56cbfSMarkus Mayer unsigned int clk_mult;
42cdb56cbfSMarkus Mayer unsigned int max_freqs;
43cdb56cbfSMarkus Mayer };
44cdb56cbfSMarkus Mayer
45cdb56cbfSMarkus Mayer #define BMIPS(c, t, m, f) { \
46cdb56cbfSMarkus Mayer .compatible = c, \
47cdb56cbfSMarkus Mayer .bmips_type = (t), \
48cdb56cbfSMarkus Mayer .clk_mult = (m), \
49cdb56cbfSMarkus Mayer .max_freqs = (f), \
50cdb56cbfSMarkus Mayer }
51cdb56cbfSMarkus Mayer
52cdb56cbfSMarkus Mayer static struct cpufreq_compat bmips_cpufreq_compat[] = {
53cdb56cbfSMarkus Mayer BMIPS("brcm,bmips5000", BMIPS5000, 8, 4),
54cdb56cbfSMarkus Mayer BMIPS("brcm,bmips5200", BMIPS5200, 8, 4),
55cdb56cbfSMarkus Mayer { }
56cdb56cbfSMarkus Mayer };
57cdb56cbfSMarkus Mayer
58cdb56cbfSMarkus Mayer static struct cpufreq_compat *priv;
59cdb56cbfSMarkus Mayer
htp_freq_to_cpu_freq(unsigned int clk_mult)60cdb56cbfSMarkus Mayer static int htp_freq_to_cpu_freq(unsigned int clk_mult)
61cdb56cbfSMarkus Mayer {
62cdb56cbfSMarkus Mayer return mips_hpt_frequency * clk_mult / 1000;
63cdb56cbfSMarkus Mayer }
64cdb56cbfSMarkus Mayer
65cdb56cbfSMarkus Mayer static struct cpufreq_frequency_table *
bmips_cpufreq_get_freq_table(const struct cpufreq_policy * policy)66cdb56cbfSMarkus Mayer bmips_cpufreq_get_freq_table(const struct cpufreq_policy *policy)
67cdb56cbfSMarkus Mayer {
68cdb56cbfSMarkus Mayer struct cpufreq_frequency_table *table;
69cdb56cbfSMarkus Mayer unsigned long cpu_freq;
70cdb56cbfSMarkus Mayer int i;
71cdb56cbfSMarkus Mayer
72cdb56cbfSMarkus Mayer cpu_freq = htp_freq_to_cpu_freq(priv->clk_mult);
73cdb56cbfSMarkus Mayer
746da2ec56SKees Cook table = kmalloc_array(priv->max_freqs + 1, sizeof(*table), GFP_KERNEL);
75cdb56cbfSMarkus Mayer if (!table)
76cdb56cbfSMarkus Mayer return ERR_PTR(-ENOMEM);
77cdb56cbfSMarkus Mayer
78cdb56cbfSMarkus Mayer for (i = 0; i < priv->max_freqs; i++) {
79cdb56cbfSMarkus Mayer table[i].frequency = cpu_freq / (1 << i);
80cdb56cbfSMarkus Mayer table[i].driver_data = i;
81cdb56cbfSMarkus Mayer }
82cdb56cbfSMarkus Mayer table[i].frequency = CPUFREQ_TABLE_END;
83cdb56cbfSMarkus Mayer
84cdb56cbfSMarkus Mayer return table;
85cdb56cbfSMarkus Mayer }
86cdb56cbfSMarkus Mayer
bmips_cpufreq_get(unsigned int cpu)87cdb56cbfSMarkus Mayer static unsigned int bmips_cpufreq_get(unsigned int cpu)
88cdb56cbfSMarkus Mayer {
89cdb56cbfSMarkus Mayer unsigned int div;
90cdb56cbfSMarkus Mayer uint32_t mode;
91cdb56cbfSMarkus Mayer
92cdb56cbfSMarkus Mayer switch (priv->bmips_type) {
93cdb56cbfSMarkus Mayer case BMIPS5200:
94cdb56cbfSMarkus Mayer case BMIPS5000:
95cdb56cbfSMarkus Mayer mode = read_c0_brcm_mode();
96cdb56cbfSMarkus Mayer div = ((mode >> BMIPS5_CLK_DIV_SHIFT) & BMIPS5_CLK_DIV_MASK);
97cdb56cbfSMarkus Mayer break;
98cdb56cbfSMarkus Mayer default:
99cdb56cbfSMarkus Mayer div = 0;
100cdb56cbfSMarkus Mayer }
101cdb56cbfSMarkus Mayer
102cdb56cbfSMarkus Mayer return htp_freq_to_cpu_freq(priv->clk_mult) / (1 << div);
103cdb56cbfSMarkus Mayer }
104cdb56cbfSMarkus Mayer
bmips_cpufreq_target_index(struct cpufreq_policy * policy,unsigned int index)105cdb56cbfSMarkus Mayer static int bmips_cpufreq_target_index(struct cpufreq_policy *policy,
106cdb56cbfSMarkus Mayer unsigned int index)
107cdb56cbfSMarkus Mayer {
108cdb56cbfSMarkus Mayer unsigned int div = policy->freq_table[index].driver_data;
109cdb56cbfSMarkus Mayer
110cdb56cbfSMarkus Mayer switch (priv->bmips_type) {
111cdb56cbfSMarkus Mayer case BMIPS5200:
112cdb56cbfSMarkus Mayer case BMIPS5000:
113cdb56cbfSMarkus Mayer change_c0_brcm_mode(BMIPS5_CLK_DIV_MASK << BMIPS5_CLK_DIV_SHIFT,
114cdb56cbfSMarkus Mayer (1 << BMIPS5_CLK_DIV_SET_SHIFT) |
115cdb56cbfSMarkus Mayer (div << BMIPS5_CLK_DIV_SHIFT));
116cdb56cbfSMarkus Mayer break;
117cdb56cbfSMarkus Mayer default:
118cdb56cbfSMarkus Mayer return -ENOTSUPP;
119cdb56cbfSMarkus Mayer }
120cdb56cbfSMarkus Mayer
121cdb56cbfSMarkus Mayer return 0;
122cdb56cbfSMarkus Mayer }
123cdb56cbfSMarkus Mayer
bmips_cpufreq_exit(struct cpufreq_policy * policy)124*b4b1ddc9SLizhe static void bmips_cpufreq_exit(struct cpufreq_policy *policy)
125cdb56cbfSMarkus Mayer {
126cdb56cbfSMarkus Mayer kfree(policy->freq_table);
127cdb56cbfSMarkus Mayer }
128cdb56cbfSMarkus Mayer
bmips_cpufreq_init(struct cpufreq_policy * policy)129cdb56cbfSMarkus Mayer static int bmips_cpufreq_init(struct cpufreq_policy *policy)
130cdb56cbfSMarkus Mayer {
131cdb56cbfSMarkus Mayer struct cpufreq_frequency_table *freq_table;
132cdb56cbfSMarkus Mayer
133cdb56cbfSMarkus Mayer freq_table = bmips_cpufreq_get_freq_table(policy);
134cdb56cbfSMarkus Mayer if (IS_ERR(freq_table)) {
135c4dcc8a1SViresh Kumar pr_err("%s: couldn't determine frequency table (%ld).\n",
136c4dcc8a1SViresh Kumar BMIPS_CPUFREQ_NAME, PTR_ERR(freq_table));
137c4dcc8a1SViresh Kumar return PTR_ERR(freq_table);
138cdb56cbfSMarkus Mayer }
139cdb56cbfSMarkus Mayer
140c4dcc8a1SViresh Kumar cpufreq_generic_init(policy, freq_table, TRANSITION_LATENCY);
141cdb56cbfSMarkus Mayer pr_info("%s: registered\n", BMIPS_CPUFREQ_NAME);
142cdb56cbfSMarkus Mayer
143c4dcc8a1SViresh Kumar return 0;
144cdb56cbfSMarkus Mayer }
145cdb56cbfSMarkus Mayer
146cdb56cbfSMarkus Mayer static struct cpufreq_driver bmips_cpufreq_driver = {
147cdb56cbfSMarkus Mayer .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK,
148cdb56cbfSMarkus Mayer .verify = cpufreq_generic_frequency_table_verify,
149cdb56cbfSMarkus Mayer .target_index = bmips_cpufreq_target_index,
150cdb56cbfSMarkus Mayer .get = bmips_cpufreq_get,
151cdb56cbfSMarkus Mayer .init = bmips_cpufreq_init,
152cdb56cbfSMarkus Mayer .exit = bmips_cpufreq_exit,
153cdb56cbfSMarkus Mayer .attr = cpufreq_generic_attr,
154cdb56cbfSMarkus Mayer .name = BMIPS_CPUFREQ_PREFIX,
155cdb56cbfSMarkus Mayer };
156cdb56cbfSMarkus Mayer
bmips_cpufreq_driver_init(void)1573359d527SZhang Jianhua static int __init bmips_cpufreq_driver_init(void)
158cdb56cbfSMarkus Mayer {
159cdb56cbfSMarkus Mayer struct cpufreq_compat *cc;
160cdb56cbfSMarkus Mayer struct device_node *np;
161cdb56cbfSMarkus Mayer
162cdb56cbfSMarkus Mayer for (cc = bmips_cpufreq_compat; cc->compatible; cc++) {
163cdb56cbfSMarkus Mayer np = of_find_compatible_node(NULL, "cpu", cc->compatible);
164cdb56cbfSMarkus Mayer if (np) {
165cdb56cbfSMarkus Mayer of_node_put(np);
166cdb56cbfSMarkus Mayer priv = cc;
167cdb56cbfSMarkus Mayer break;
168cdb56cbfSMarkus Mayer }
169cdb56cbfSMarkus Mayer }
170cdb56cbfSMarkus Mayer
171cdb56cbfSMarkus Mayer /* We hit the guard element of the array. No compatible CPU found. */
172cdb56cbfSMarkus Mayer if (!cc->compatible)
173cdb56cbfSMarkus Mayer return -ENODEV;
174cdb56cbfSMarkus Mayer
175cdb56cbfSMarkus Mayer return cpufreq_register_driver(&bmips_cpufreq_driver);
176cdb56cbfSMarkus Mayer }
1773359d527SZhang Jianhua module_init(bmips_cpufreq_driver_init);
1783359d527SZhang Jianhua
bmips_cpufreq_driver_exit(void)1793359d527SZhang Jianhua static void __exit bmips_cpufreq_driver_exit(void)
1803359d527SZhang Jianhua {
1813359d527SZhang Jianhua cpufreq_unregister_driver(&bmips_cpufreq_driver);
1823359d527SZhang Jianhua }
1833359d527SZhang Jianhua module_exit(bmips_cpufreq_driver_exit);
184cdb56cbfSMarkus Mayer
185cdb56cbfSMarkus Mayer MODULE_AUTHOR("Markus Mayer <mmayer@broadcom.com>");
186cdb56cbfSMarkus Mayer MODULE_DESCRIPTION("CPUfreq driver for Broadcom BMIPS SoCs");
187cdb56cbfSMarkus Mayer MODULE_LICENSE("GPL");
188