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;
72 * hardware specific functions
75 static struct of_device *pmi_dev;
77 static int set_pmode_pmi(int cpu, unsigned int pmode)
80 pmi_message_t pmi_msg;
85 pmi_msg.type = PMI_TYPE_FREQ_CHANGE;
86 pmi_msg.data1 = cbe_cpu_to_node(cpu);
87 pmi_msg.data2 = pmode;
90 time = (u64) get_cycles();
93 pmi_send_message(pmi_dev, pmi_msg);
96 pr_debug("PMI returned slow mode %d\n", ret);
99 time = (u64) get_cycles() - time; /* actual cycles (not cpu cycles!) */
100 time = 1000000000 * time / CLOCK_TICK_RATE; /* time in ns (10^-9) */
101 pr_debug("had to wait %lu ns for a transition\n", time);
107 static int get_pmode(int cpu)
110 struct cbe_pmd_regs __iomem *pmd_regs;
112 pmd_regs = cbe_get_cpu_pmd_regs(cpu);
113 ret = in_be64(&pmd_regs->pmsr) & 0x07;
118 static int set_pmode_reg(int cpu, unsigned int pmode)
120 struct cbe_pmd_regs __iomem *pmd_regs;
121 struct cbe_mic_tm_regs __iomem *mic_tm_regs;
125 local_irq_save(flags);
127 mic_tm_regs = cbe_get_cpu_mic_tm_regs(cpu);
128 pmd_regs = cbe_get_cpu_pmd_regs(cpu);
130 pr_debug("pm register is mapped at %p\n", &pmd_regs->pmcr);
131 pr_debug("mic register is mapped at %p\n", &mic_tm_regs->slow_fast_timer_0);
133 out_be64(&mic_tm_regs->slow_fast_timer_0, MIC_Slow_Fast_Timer_table[pmode]);
134 out_be64(&mic_tm_regs->slow_fast_timer_1, MIC_Slow_Fast_Timer_table[pmode]);
136 out_be64(&mic_tm_regs->slow_next_timer_0, MIC_Slow_Next_Timer_table[pmode]);
137 out_be64(&mic_tm_regs->slow_next_timer_1, MIC_Slow_Next_Timer_table[pmode]);
139 value = in_be64(&pmd_regs->pmcr);
140 /* set bits to zero */
141 value &= 0xFFFFFFFFFFFFFFF8ull;
142 /* set bits to next pmode */
145 out_be64(&pmd_regs->pmcr, value);
147 /* wait until new pmode appears in status register */
148 value = in_be64(&pmd_regs->pmsr) & 0x07;
149 while(value != pmode) {
151 value = in_be64(&pmd_regs->pmsr) & 0x07;
154 local_irq_restore(flags);
159 static int set_pmode(int cpu, unsigned int slow_mode) {
161 return set_pmode_pmi(cpu, slow_mode);
163 return set_pmode_reg(cpu, slow_mode);
166 static void cbe_cpufreq_handle_pmi(struct of_device *dev, pmi_message_t pmi_msg)
171 BUG_ON(pmi_msg.type != PMI_TYPE_FREQ_CHANGE);
173 cpu = cbe_node_to_cpu(pmi_msg.data1);
174 cbe_pmode_new = pmi_msg.data2;
176 pmi_frequency_limit = cbe_freqs[cbe_pmode_new].frequency;
178 pr_debug("cbe_handle_pmi: max freq=%d\n", pmi_frequency_limit);
181 static int pmi_notifier(struct notifier_block *nb,
182 unsigned long event, void *data)
184 struct cpufreq_policy *policy = data;
186 if (event != CPUFREQ_INCOMPATIBLE)
189 cpufreq_verify_within_limits(policy, 0, pmi_frequency_limit);
193 static struct notifier_block pmi_notifier_block = {
194 .notifier_call = pmi_notifier,
197 static struct pmi_handler cbe_pmi_handler = {
198 .type = PMI_TYPE_FREQ_CHANGE,
199 .handle_pmi_message = cbe_cpufreq_handle_pmi,
207 static int cbe_cpufreq_cpu_init(struct cpufreq_policy *policy)
209 const u32 *max_freqp;
212 struct device_node *cpu;
214 cpu = of_get_cpu_node(policy->cpu, NULL);
219 pr_debug("init cpufreq on CPU %d\n", policy->cpu);
221 max_freqp = of_get_property(cpu, "clock-frequency", NULL);
226 /* we need the freq in kHz */
227 max_freq = *max_freqp / 1000;
229 pr_debug("max clock-frequency is at %u kHz\n", max_freq);
230 pr_debug("initializing frequency table\n");
232 /* initialize frequency table */
233 for (i=0; cbe_freqs[i].frequency!=CPUFREQ_TABLE_END; i++) {
234 cbe_freqs[i].frequency = max_freq / cbe_freqs[i].index;
235 pr_debug("%d: %d\n", i, cbe_freqs[i].frequency);
238 policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
239 /* if DEBUG is enabled set_pmode() measures the correct latency of a transition */
240 policy->cpuinfo.transition_latency = 25000;
242 cur_pmode = get_pmode(policy->cpu);
243 pr_debug("current pmode is at %d\n",cur_pmode);
245 policy->cur = cbe_freqs[cur_pmode].frequency;
248 policy->cpus = cpu_sibling_map[policy->cpu];
251 cpufreq_frequency_table_get_attr(cbe_freqs, policy->cpu);
254 /* frequency might get limited later, initialize limit with max_freq */
255 pmi_frequency_limit = max_freq;
256 cpufreq_register_notifier(&pmi_notifier_block, CPUFREQ_POLICY_NOTIFIER);
259 /* this ensures that policy->cpuinfo_min and policy->cpuinfo_max are set correctly */
260 return cpufreq_frequency_table_cpuinfo(policy, cbe_freqs);
263 static int cbe_cpufreq_cpu_exit(struct cpufreq_policy *policy)
266 cpufreq_unregister_notifier(&pmi_notifier_block, CPUFREQ_POLICY_NOTIFIER);
268 cpufreq_frequency_table_put_attr(policy->cpu);
272 static int cbe_cpufreq_verify(struct cpufreq_policy *policy)
274 return cpufreq_frequency_table_verify(policy, cbe_freqs);
278 static int cbe_cpufreq_target(struct cpufreq_policy *policy, unsigned int target_freq,
279 unsigned int relation)
282 struct cpufreq_freqs freqs;
285 cpufreq_frequency_table_target(policy,
291 freqs.old = policy->cur;
292 freqs.new = cbe_freqs[cbe_pmode_new].frequency;
293 freqs.cpu = policy->cpu;
295 mutex_lock(&cbe_switch_mutex);
296 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
298 pr_debug("setting frequency for cpu %d to %d kHz, 1/%d of max frequency\n",
300 cbe_freqs[cbe_pmode_new].frequency,
301 cbe_freqs[cbe_pmode_new].index);
303 rc = set_pmode(policy->cpu, cbe_pmode_new);
304 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
305 mutex_unlock(&cbe_switch_mutex);
310 static struct cpufreq_driver cbe_cpufreq_driver = {
311 .verify = cbe_cpufreq_verify,
312 .target = cbe_cpufreq_target,
313 .init = cbe_cpufreq_cpu_init,
314 .exit = cbe_cpufreq_cpu_exit,
315 .name = "cbe-cpufreq",
316 .owner = THIS_MODULE,
317 .flags = CPUFREQ_CONST_LOOPS,
321 * module init and destoy
324 static int __init cbe_cpufreq_init(void)
326 struct device_node *np;
328 if (!machine_is(cell))
331 np = of_find_node_by_type(NULL, "ibm,pmi");
333 pmi_dev = of_find_device_by_node(np);
336 pmi_register_handler(pmi_dev, &cbe_pmi_handler);
338 return cpufreq_register_driver(&cbe_cpufreq_driver);
341 static void __exit cbe_cpufreq_exit(void)
344 pmi_unregister_handler(pmi_dev, &cbe_pmi_handler);
346 cpufreq_unregister_driver(&cbe_cpufreq_driver);
349 module_init(cbe_cpufreq_init);
350 module_exit(cbe_cpufreq_exit);
352 MODULE_LICENSE("GPL");
353 MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");