2 * cpufreq driver for the cell processor
4 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
6 * Author: Christian Krafft <krafft@de.ibm.com>
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)
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.
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.
23 #include <linux/cpufreq.h>
24 #include <linux/timer.h>
26 #include <asm/hw_irq.h>
28 #include <asm/machdep.h>
29 #include <asm/processor.h>
33 #include <asm/of_platform.h>
37 static DEFINE_MUTEX(cbe_switch_mutex);
40 /* the CBE supports an 8 step frequency scaling */
41 static struct cpufreq_frequency_table cbe_freqs[] = {
50 {0, CPUFREQ_TABLE_END},
53 /* to write to MIC register */
54 static u64 MIC_Slow_Fast_Timer_table[] = {
55 [0 ... 7] = 0x007fc00000000000ull,
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,
70 static unsigned int pmi_frequency_limit = 0;
73 * hardware specific functions
76 static bool cbe_cpufreq_has_pmi;
79 static int set_pmode_pmi(int cpu, unsigned int pmode)
82 pmi_message_t pmi_msg;
87 pmi_msg.type = PMI_TYPE_FREQ_CHANGE;
88 pmi_msg.data1 = cbe_cpu_to_node(cpu);
89 pmi_msg.data2 = pmode;
95 pmi_send_message(pmi_msg);
98 pr_debug("PMI returned slow mode %d\n", ret);
101 time = jiffies - time; /* actual cycles (not cpu cycles!) */
102 time = jiffies_to_msecs(time);
103 pr_debug("had to wait %lu ms for a transition using PMI.\n", time);
109 static int get_pmode(int cpu)
112 struct cbe_pmd_regs __iomem *pmd_regs;
114 pmd_regs = cbe_get_cpu_pmd_regs(cpu);
115 ret = in_be64(&pmd_regs->pmsr) & 0x07;
120 static int set_pmode_reg(int cpu, unsigned int pmode)
122 struct cbe_pmd_regs __iomem *pmd_regs;
123 struct cbe_mic_tm_regs __iomem *mic_tm_regs;
130 local_irq_save(flags);
132 mic_tm_regs = cbe_get_cpu_mic_tm_regs(cpu);
133 pmd_regs = cbe_get_cpu_pmd_regs(cpu);
138 out_be64(&mic_tm_regs->slow_fast_timer_0, MIC_Slow_Fast_Timer_table[pmode]);
139 out_be64(&mic_tm_regs->slow_fast_timer_1, MIC_Slow_Fast_Timer_table[pmode]);
141 out_be64(&mic_tm_regs->slow_next_timer_0, MIC_Slow_Next_Timer_table[pmode]);
142 out_be64(&mic_tm_regs->slow_next_timer_1, MIC_Slow_Next_Timer_table[pmode]);
144 value = in_be64(&pmd_regs->pmcr);
145 /* set bits to zero */
146 value &= 0xFFFFFFFFFFFFFFF8ull;
147 /* set bits to next pmode */
150 out_be64(&pmd_regs->pmcr, value);
153 /* wait until new pmode appears in status register */
154 value = in_be64(&pmd_regs->pmsr) & 0x07;
155 while(value != pmode) {
157 value = in_be64(&pmd_regs->pmsr) & 0x07;
160 time = jiffies - time;
161 time = jiffies_to_msecs(time);
162 pr_debug("had to wait %lu ms for a transition using " \
163 "the pervasive unit.\n", time);
165 local_irq_restore(flags);
170 static int set_pmode(int cpu, unsigned int slow_mode)
172 #ifdef CONFIG_PPC_PMI
173 if (cbe_cpufreq_has_pmi)
174 return set_pmode_pmi(cpu, slow_mode);
176 return set_pmode_reg(cpu, slow_mode);
179 static void cbe_cpufreq_handle_pmi(pmi_message_t pmi_msg)
184 BUG_ON(pmi_msg.type != PMI_TYPE_FREQ_CHANGE);
186 cpu = cbe_node_to_cpu(pmi_msg.data1);
187 cbe_pmode_new = pmi_msg.data2;
189 pmi_frequency_limit = cbe_freqs[cbe_pmode_new].frequency;
191 pr_debug("cbe_handle_pmi: max freq=%d\n", pmi_frequency_limit);
194 static int pmi_notifier(struct notifier_block *nb,
195 unsigned long event, void *data)
197 struct cpufreq_policy *policy = data;
199 if (pmi_frequency_limit)
200 cpufreq_verify_within_limits(policy, 0, pmi_frequency_limit);
205 static struct notifier_block pmi_notifier_block = {
206 .notifier_call = pmi_notifier,
209 static struct pmi_handler cbe_pmi_handler = {
210 .type = PMI_TYPE_FREQ_CHANGE,
211 .handle_pmi_message = cbe_cpufreq_handle_pmi,
219 static int cbe_cpufreq_cpu_init(struct cpufreq_policy *policy)
221 const u32 *max_freqp;
224 struct device_node *cpu;
226 cpu = of_get_cpu_node(policy->cpu, NULL);
231 pr_debug("init cpufreq on CPU %d\n", policy->cpu);
233 max_freqp = of_get_property(cpu, "clock-frequency", NULL);
238 /* we need the freq in kHz */
239 max_freq = *max_freqp / 1000;
241 pr_debug("max clock-frequency is at %u kHz\n", max_freq);
242 pr_debug("initializing frequency table\n");
244 /* initialize frequency table */
245 for (i=0; cbe_freqs[i].frequency!=CPUFREQ_TABLE_END; i++) {
246 cbe_freqs[i].frequency = max_freq / cbe_freqs[i].index;
247 pr_debug("%d: %d\n", i, cbe_freqs[i].frequency);
250 policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
251 /* if DEBUG is enabled set_pmode() measures the correct latency of a transition */
252 policy->cpuinfo.transition_latency = 25000;
254 cur_pmode = get_pmode(policy->cpu);
255 pr_debug("current pmode is at %d\n",cur_pmode);
257 policy->cur = cbe_freqs[cur_pmode].frequency;
260 policy->cpus = cpu_sibling_map[policy->cpu];
263 cpufreq_frequency_table_get_attr(cbe_freqs, policy->cpu);
266 /* this ensures that policy->cpuinfo_min and policy->cpuinfo_max are set correctly */
267 return cpufreq_frequency_table_cpuinfo(policy, cbe_freqs);
270 static int cbe_cpufreq_cpu_exit(struct cpufreq_policy *policy)
272 cpufreq_frequency_table_put_attr(policy->cpu);
276 static int cbe_cpufreq_verify(struct cpufreq_policy *policy)
278 return cpufreq_frequency_table_verify(policy, cbe_freqs);
282 static int cbe_cpufreq_target(struct cpufreq_policy *policy, unsigned int target_freq,
283 unsigned int relation)
286 struct cpufreq_freqs freqs;
289 cpufreq_frequency_table_target(policy,
295 freqs.old = policy->cur;
296 freqs.new = cbe_freqs[cbe_pmode_new].frequency;
297 freqs.cpu = policy->cpu;
299 mutex_lock(&cbe_switch_mutex);
300 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
302 pr_debug("setting frequency for cpu %d to %d kHz, 1/%d of max frequency\n",
304 cbe_freqs[cbe_pmode_new].frequency,
305 cbe_freqs[cbe_pmode_new].index);
307 rc = set_pmode(policy->cpu, cbe_pmode_new);
308 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
309 mutex_unlock(&cbe_switch_mutex);
314 static struct cpufreq_driver cbe_cpufreq_driver = {
315 .verify = cbe_cpufreq_verify,
316 .target = cbe_cpufreq_target,
317 .init = cbe_cpufreq_cpu_init,
318 .exit = cbe_cpufreq_cpu_exit,
319 .name = "cbe-cpufreq",
320 .owner = THIS_MODULE,
321 .flags = CPUFREQ_CONST_LOOPS,
325 * module init and destoy
328 static int __init cbe_cpufreq_init(void)
330 if (!machine_is(cell))
333 cbe_cpufreq_has_pmi = pmi_register_handler(&cbe_pmi_handler) == 0;
335 if (cbe_cpufreq_has_pmi)
336 cpufreq_register_notifier(&pmi_notifier_block, CPUFREQ_POLICY_NOTIFIER);
338 return cpufreq_register_driver(&cbe_cpufreq_driver);
341 static void __exit cbe_cpufreq_exit(void)
343 cpufreq_unregister_driver(&cbe_cpufreq_driver);
345 if (cbe_cpufreq_has_pmi) {
346 cpufreq_unregister_notifier(&pmi_notifier_block, CPUFREQ_POLICY_NOTIFIER);
347 pmi_unregister_handler(&cbe_pmi_handler);
351 module_init(cbe_cpufreq_init);
352 module_exit(cbe_cpufreq_exit);
354 MODULE_LICENSE("GPL");
355 MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");