Pull percpu-dtc into release branch
[linux-2.6] / arch / powerpc / platforms / cell / cbe_cpufreq.c
1 /*
2  * cpufreq driver for the cell processor
3  *
4  * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
5  *
6  * Author: Christian Krafft <krafft@de.ibm.com>
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; either version 2, or (at your option)
11  * any later version.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the Free Software
20  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21  */
22
23 #include <linux/cpufreq.h>
24 #include <linux/timer.h>
25
26 #include <asm/hw_irq.h>
27 #include <asm/io.h>
28 #include <asm/machdep.h>
29 #include <asm/processor.h>
30 #include <asm/prom.h>
31 #include <asm/time.h>
32 #include <asm/pmi.h>
33 #include <asm/of_platform.h>
34
35 #include "cbe_regs.h"
36
37 static DEFINE_MUTEX(cbe_switch_mutex);
38
39
40 /* the CBE supports an 8 step frequency scaling */
41 static struct cpufreq_frequency_table cbe_freqs[] = {
42         {1,     0},
43         {2,     0},
44         {3,     0},
45         {4,     0},
46         {5,     0},
47         {6,     0},
48         {8,     0},
49         {10,    0},
50         {0,     CPUFREQ_TABLE_END},
51 };
52
53 /* to write to MIC register */
54 static u64 MIC_Slow_Fast_Timer_table[] = {
55         [0 ... 7] = 0x007fc00000000000ull,
56 };
57
58 /* more values for the MIC */
59 static u64 MIC_Slow_Next_Timer_table[] = {
60         0x0000240000000000ull,
61         0x0000268000000000ull,
62         0x000029C000000000ull,
63         0x00002D0000000000ull,
64         0x0000300000000000ull,
65         0x0000334000000000ull,
66         0x000039C000000000ull,
67         0x00003FC000000000ull,
68 };
69
70 /*
71  * hardware specific functions
72  */
73
74 static struct of_device *pmi_dev;
75
76 static int set_pmode_pmi(int cpu, unsigned int pmode)
77 {
78         int ret;
79         pmi_message_t pmi_msg;
80 #ifdef DEBUG
81         u64 time;
82 #endif
83
84         pmi_msg.type = PMI_TYPE_FREQ_CHANGE;
85         pmi_msg.data1 = cbe_cpu_to_node(cpu);
86         pmi_msg.data2 = pmode;
87
88 #ifdef DEBUG
89         time = (u64) get_cycles();
90 #endif
91
92         pmi_send_message(pmi_dev, pmi_msg);
93         ret = pmi_msg.data2;
94
95         pr_debug("PMI returned slow mode %d\n", ret);
96
97 #ifdef DEBUG
98         time = (u64) get_cycles() - time; /* actual cycles (not cpu cycles!) */
99         time = 1000000000 * time / CLOCK_TICK_RATE; /* time in ns (10^-9) */
100         pr_debug("had to wait %lu ns for a transition\n", time);
101 #endif
102         return ret;
103 }
104
105
106 static int get_pmode(int cpu)
107 {
108         int ret;
109         struct cbe_pmd_regs __iomem *pmd_regs;
110
111         pmd_regs = cbe_get_cpu_pmd_regs(cpu);
112         ret = in_be64(&pmd_regs->pmsr) & 0x07;
113
114         return ret;
115 }
116
117 static int set_pmode_reg(int cpu, unsigned int pmode)
118 {
119         struct cbe_pmd_regs __iomem *pmd_regs;
120         struct cbe_mic_tm_regs __iomem *mic_tm_regs;
121         u64 flags;
122         u64 value;
123
124         local_irq_save(flags);
125
126         mic_tm_regs = cbe_get_cpu_mic_tm_regs(cpu);
127         pmd_regs = cbe_get_cpu_pmd_regs(cpu);
128
129         pr_debug("pm register is mapped at %p\n", &pmd_regs->pmcr);
130         pr_debug("mic register is mapped at %p\n", &mic_tm_regs->slow_fast_timer_0);
131
132         out_be64(&mic_tm_regs->slow_fast_timer_0, MIC_Slow_Fast_Timer_table[pmode]);
133         out_be64(&mic_tm_regs->slow_fast_timer_1, MIC_Slow_Fast_Timer_table[pmode]);
134
135         out_be64(&mic_tm_regs->slow_next_timer_0, MIC_Slow_Next_Timer_table[pmode]);
136         out_be64(&mic_tm_regs->slow_next_timer_1, MIC_Slow_Next_Timer_table[pmode]);
137
138         value = in_be64(&pmd_regs->pmcr);
139         /* set bits to zero */
140         value &= 0xFFFFFFFFFFFFFFF8ull;
141         /* set bits to next pmode */
142         value |= pmode;
143
144         out_be64(&pmd_regs->pmcr, value);
145
146         /* wait until new pmode appears in status register */
147         value = in_be64(&pmd_regs->pmsr) & 0x07;
148         while(value != pmode) {
149                 cpu_relax();
150                 value = in_be64(&pmd_regs->pmsr) & 0x07;
151         }
152
153         local_irq_restore(flags);
154
155         return 0;
156 }
157
158 static int set_pmode(int cpu, unsigned int slow_mode) {
159         if (pmi_dev)
160                 return set_pmode_pmi(cpu, slow_mode);
161         else
162                 return set_pmode_reg(cpu, slow_mode);
163 }
164
165 static void cbe_cpufreq_handle_pmi(struct of_device *dev, pmi_message_t pmi_msg)
166 {
167         struct cpufreq_policy policy;
168         u8 cpu;
169         u8 cbe_pmode_new;
170
171         BUG_ON(pmi_msg.type != PMI_TYPE_FREQ_CHANGE);
172
173         cpu = cbe_node_to_cpu(pmi_msg.data1);
174         cbe_pmode_new = pmi_msg.data2;
175
176         cpufreq_get_policy(&policy, cpu);
177
178         policy.max = min(policy.max, cbe_freqs[cbe_pmode_new].frequency);
179         policy.min = min(policy.min, policy.max);
180
181         pr_debug("cbe_handle_pmi: new policy.min=%d policy.max=%d\n", policy.min, policy.max);
182         cpufreq_set_policy(&policy);
183 }
184
185 static struct pmi_handler cbe_pmi_handler = {
186         .type                   = PMI_TYPE_FREQ_CHANGE,
187         .handle_pmi_message     = cbe_cpufreq_handle_pmi,
188 };
189
190
191 /*
192  * cpufreq functions
193  */
194
195 static int cbe_cpufreq_cpu_init(struct cpufreq_policy *policy)
196 {
197         const u32 *max_freqp;
198         u32 max_freq;
199         int i, cur_pmode;
200         struct device_node *cpu;
201
202         cpu = of_get_cpu_node(policy->cpu, NULL);
203
204         if (!cpu)
205                 return -ENODEV;
206
207         pr_debug("init cpufreq on CPU %d\n", policy->cpu);
208
209         max_freqp = of_get_property(cpu, "clock-frequency", NULL);
210
211         if (!max_freqp)
212                 return -EINVAL;
213
214         /* we need the freq in kHz */
215         max_freq = *max_freqp / 1000;
216
217         pr_debug("max clock-frequency is at %u kHz\n", max_freq);
218         pr_debug("initializing frequency table\n");
219
220         /* initialize frequency table */
221         for (i=0; cbe_freqs[i].frequency!=CPUFREQ_TABLE_END; i++) {
222                 cbe_freqs[i].frequency = max_freq / cbe_freqs[i].index;
223                 pr_debug("%d: %d\n", i, cbe_freqs[i].frequency);
224         }
225
226         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
227         /* if DEBUG is enabled set_pmode() measures the correct latency of a transition */
228         policy->cpuinfo.transition_latency = 25000;
229
230         cur_pmode = get_pmode(policy->cpu);
231         pr_debug("current pmode is at %d\n",cur_pmode);
232
233         policy->cur = cbe_freqs[cur_pmode].frequency;
234
235 #ifdef CONFIG_SMP
236         policy->cpus = cpu_sibling_map[policy->cpu];
237 #endif
238
239         cpufreq_frequency_table_get_attr(cbe_freqs, policy->cpu);
240
241         /* this ensures that policy->cpuinfo_min and policy->cpuinfo_max are set correctly */
242         return cpufreq_frequency_table_cpuinfo(policy, cbe_freqs);
243 }
244
245 static int cbe_cpufreq_cpu_exit(struct cpufreq_policy *policy)
246 {
247         cpufreq_frequency_table_put_attr(policy->cpu);
248         return 0;
249 }
250
251 static int cbe_cpufreq_verify(struct cpufreq_policy *policy)
252 {
253         return cpufreq_frequency_table_verify(policy, cbe_freqs);
254 }
255
256
257 static int cbe_cpufreq_target(struct cpufreq_policy *policy, unsigned int target_freq,
258                             unsigned int relation)
259 {
260         int rc;
261         struct cpufreq_freqs freqs;
262         int cbe_pmode_new;
263
264         cpufreq_frequency_table_target(policy,
265                                        cbe_freqs,
266                                        target_freq,
267                                        relation,
268                                        &cbe_pmode_new);
269
270         freqs.old = policy->cur;
271         freqs.new = cbe_freqs[cbe_pmode_new].frequency;
272         freqs.cpu = policy->cpu;
273
274         mutex_lock(&cbe_switch_mutex);
275         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
276
277         pr_debug("setting frequency for cpu %d to %d kHz, 1/%d of max frequency\n",
278                  policy->cpu,
279                  cbe_freqs[cbe_pmode_new].frequency,
280                  cbe_freqs[cbe_pmode_new].index);
281
282         rc = set_pmode(policy->cpu, cbe_pmode_new);
283         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
284         mutex_unlock(&cbe_switch_mutex);
285
286         return rc;
287 }
288
289 static struct cpufreq_driver cbe_cpufreq_driver = {
290         .verify         = cbe_cpufreq_verify,
291         .target         = cbe_cpufreq_target,
292         .init           = cbe_cpufreq_cpu_init,
293         .exit           = cbe_cpufreq_cpu_exit,
294         .name           = "cbe-cpufreq",
295         .owner          = THIS_MODULE,
296         .flags          = CPUFREQ_CONST_LOOPS,
297 };
298
299 /*
300  * module init and destoy
301  */
302
303 static int __init cbe_cpufreq_init(void)
304 {
305         struct device_node *np;
306
307         if (!machine_is(cell))
308                 return -ENODEV;
309
310         np = of_find_node_by_type(NULL, "ibm,pmi");
311
312         pmi_dev = of_find_device_by_node(np);
313
314         if (pmi_dev)
315                 pmi_register_handler(pmi_dev, &cbe_pmi_handler);
316
317         return cpufreq_register_driver(&cbe_cpufreq_driver);
318 }
319
320 static void __exit cbe_cpufreq_exit(void)
321 {
322         if (pmi_dev)
323                 pmi_unregister_handler(pmi_dev, &cbe_pmi_handler);
324
325         cpufreq_unregister_driver(&cbe_cpufreq_driver);
326 }
327
328 module_init(cbe_cpufreq_init);
329 module_exit(cbe_cpufreq_exit);
330
331 MODULE_LICENSE("GPL");
332 MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");