GNU Linux-libre 4.4.289-gnu1
[releases.git] / drivers / cpufreq / sparc-us3-cpufreq.c
1 /* us3_cpufreq.c: UltraSPARC-III cpu frequency support
2  *
3  * Copyright (C) 2003 David S. Miller (davem@redhat.com)
4  *
5  * Many thanks to Dominik Brodowski for fixing up the cpufreq
6  * infrastructure in order to make this driver easier to implement.
7  */
8
9 #include <linux/kernel.h>
10 #include <linux/module.h>
11 #include <linux/sched.h>
12 #include <linux/smp.h>
13 #include <linux/cpufreq.h>
14 #include <linux/threads.h>
15 #include <linux/slab.h>
16 #include <linux/init.h>
17
18 #include <asm/head.h>
19 #include <asm/timer.h>
20
21 static struct cpufreq_driver *cpufreq_us3_driver;
22
23 struct us3_freq_percpu_info {
24         struct cpufreq_frequency_table table[4];
25 };
26
27 /* Indexed by cpu number. */
28 static struct us3_freq_percpu_info *us3_freq_table;
29
30 /* UltraSPARC-III has three dividers: 1, 2, and 32.  These are controlled
31  * in the Safari config register.
32  */
33 #define SAFARI_CFG_DIV_1        0x0000000000000000UL
34 #define SAFARI_CFG_DIV_2        0x0000000040000000UL
35 #define SAFARI_CFG_DIV_32       0x0000000080000000UL
36 #define SAFARI_CFG_DIV_MASK     0x00000000C0000000UL
37
38 static unsigned long read_safari_cfg(void)
39 {
40         unsigned long ret;
41
42         __asm__ __volatile__("ldxa      [%%g0] %1, %0"
43                              : "=&r" (ret)
44                              : "i" (ASI_SAFARI_CONFIG));
45         return ret;
46 }
47
48 static void write_safari_cfg(unsigned long val)
49 {
50         __asm__ __volatile__("stxa      %0, [%%g0] %1\n\t"
51                              "membar    #Sync"
52                              : /* no outputs */
53                              : "r" (val), "i" (ASI_SAFARI_CONFIG)
54                              : "memory");
55 }
56
57 static unsigned long get_current_freq(unsigned int cpu, unsigned long safari_cfg)
58 {
59         unsigned long clock_tick = sparc64_get_clock_tick(cpu) / 1000;
60         unsigned long ret;
61
62         switch (safari_cfg & SAFARI_CFG_DIV_MASK) {
63         case SAFARI_CFG_DIV_1:
64                 ret = clock_tick / 1;
65                 break;
66         case SAFARI_CFG_DIV_2:
67                 ret = clock_tick / 2;
68                 break;
69         case SAFARI_CFG_DIV_32:
70                 ret = clock_tick / 32;
71                 break;
72         default:
73                 BUG();
74         }
75
76         return ret;
77 }
78
79 static unsigned int us3_freq_get(unsigned int cpu)
80 {
81         cpumask_t cpus_allowed;
82         unsigned long reg;
83         unsigned int ret;
84
85         cpumask_copy(&cpus_allowed, tsk_cpus_allowed(current));
86         set_cpus_allowed_ptr(current, cpumask_of(cpu));
87
88         reg = read_safari_cfg();
89         ret = get_current_freq(cpu, reg);
90
91         set_cpus_allowed_ptr(current, &cpus_allowed);
92
93         return ret;
94 }
95
96 static int us3_freq_target(struct cpufreq_policy *policy, unsigned int index)
97 {
98         unsigned int cpu = policy->cpu;
99         unsigned long new_bits, new_freq, reg;
100         cpumask_t cpus_allowed;
101
102         cpumask_copy(&cpus_allowed, tsk_cpus_allowed(current));
103         set_cpus_allowed_ptr(current, cpumask_of(cpu));
104
105         new_freq = sparc64_get_clock_tick(cpu) / 1000;
106         switch (index) {
107         case 0:
108                 new_bits = SAFARI_CFG_DIV_1;
109                 new_freq /= 1;
110                 break;
111         case 1:
112                 new_bits = SAFARI_CFG_DIV_2;
113                 new_freq /= 2;
114                 break;
115         case 2:
116                 new_bits = SAFARI_CFG_DIV_32;
117                 new_freq /= 32;
118                 break;
119
120         default:
121                 BUG();
122         }
123
124         reg = read_safari_cfg();
125
126         reg &= ~SAFARI_CFG_DIV_MASK;
127         reg |= new_bits;
128         write_safari_cfg(reg);
129
130         set_cpus_allowed_ptr(current, &cpus_allowed);
131
132         return 0;
133 }
134
135 static int __init us3_freq_cpu_init(struct cpufreq_policy *policy)
136 {
137         unsigned int cpu = policy->cpu;
138         unsigned long clock_tick = sparc64_get_clock_tick(cpu) / 1000;
139         struct cpufreq_frequency_table *table =
140                 &us3_freq_table[cpu].table[0];
141
142         table[0].driver_data = 0;
143         table[0].frequency = clock_tick / 1;
144         table[1].driver_data = 1;
145         table[1].frequency = clock_tick / 2;
146         table[2].driver_data = 2;
147         table[2].frequency = clock_tick / 32;
148         table[3].driver_data = 0;
149         table[3].frequency = CPUFREQ_TABLE_END;
150
151         policy->cpuinfo.transition_latency = 0;
152         policy->cur = clock_tick;
153
154         return cpufreq_table_validate_and_show(policy, table);
155 }
156
157 static int us3_freq_cpu_exit(struct cpufreq_policy *policy)
158 {
159         if (cpufreq_us3_driver)
160                 us3_freq_target(policy, 0);
161
162         return 0;
163 }
164
165 static int __init us3_freq_init(void)
166 {
167         unsigned long manuf, impl, ver;
168         int ret;
169
170         if (tlb_type != cheetah && tlb_type != cheetah_plus)
171                 return -ENODEV;
172
173         __asm__("rdpr %%ver, %0" : "=r" (ver));
174         manuf = ((ver >> 48) & 0xffff);
175         impl  = ((ver >> 32) & 0xffff);
176
177         if (manuf == CHEETAH_MANUF &&
178             (impl == CHEETAH_IMPL ||
179              impl == CHEETAH_PLUS_IMPL ||
180              impl == JAGUAR_IMPL ||
181              impl == PANTHER_IMPL)) {
182                 struct cpufreq_driver *driver;
183
184                 ret = -ENOMEM;
185                 driver = kzalloc(sizeof(*driver), GFP_KERNEL);
186                 if (!driver)
187                         goto err_out;
188
189                 us3_freq_table = kzalloc((NR_CPUS * sizeof(*us3_freq_table)),
190                         GFP_KERNEL);
191                 if (!us3_freq_table)
192                         goto err_out;
193
194                 driver->init = us3_freq_cpu_init;
195                 driver->verify = cpufreq_generic_frequency_table_verify;
196                 driver->target_index = us3_freq_target;
197                 driver->get = us3_freq_get;
198                 driver->exit = us3_freq_cpu_exit;
199                 strcpy(driver->name, "UltraSPARC-III");
200
201                 cpufreq_us3_driver = driver;
202                 ret = cpufreq_register_driver(driver);
203                 if (ret)
204                         goto err_out;
205
206                 return 0;
207
208 err_out:
209                 if (driver) {
210                         kfree(driver);
211                         cpufreq_us3_driver = NULL;
212                 }
213                 kfree(us3_freq_table);
214                 us3_freq_table = NULL;
215                 return ret;
216         }
217
218         return -ENODEV;
219 }
220
221 static void __exit us3_freq_exit(void)
222 {
223         if (cpufreq_us3_driver) {
224                 cpufreq_unregister_driver(cpufreq_us3_driver);
225                 kfree(cpufreq_us3_driver);
226                 cpufreq_us3_driver = NULL;
227                 kfree(us3_freq_table);
228                 us3_freq_table = NULL;
229         }
230 }
231
232 MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
233 MODULE_DESCRIPTION("cpufreq driver for UltraSPARC-III");
234 MODULE_LICENSE("GPL");
235
236 module_init(us3_freq_init);
237 module_exit(us3_freq_exit);