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/processor.h>
34 static DEFINE_MUTEX(cbe_switch_mutex
);
37 /* the CBE supports an 8 step frequency scaling */
38 static struct cpufreq_frequency_table cbe_freqs
[] = {
47 {0, CPUFREQ_TABLE_END
},
50 /* to write to MIC register */
51 static u64 MIC_Slow_Fast_Timer_table
[] = {
52 [0 ... 7] = 0x007fc00000000000ull
,
55 /* more values for the MIC */
56 static u64 MIC_Slow_Next_Timer_table
[] = {
57 0x0000240000000000ull
,
58 0x0000268000000000ull
,
59 0x000029C000000000ull
,
60 0x00002D0000000000ull
,
61 0x0000300000000000ull
,
62 0x0000334000000000ull
,
63 0x000039C000000000ull
,
64 0x00003FC000000000ull
,
68 * hardware specific functions
71 static int get_pmode(int cpu
)
74 struct cbe_pmd_regs __iomem
*pmd_regs
;
76 pmd_regs
= cbe_get_cpu_pmd_regs(cpu
);
77 ret
= in_be64(&pmd_regs
->pmsr
) & 0x07;
82 static int set_pmode(int cpu
, unsigned int pmode
)
84 struct cbe_pmd_regs __iomem
*pmd_regs
;
85 struct cbe_mic_tm_regs __iomem
*mic_tm_regs
;
89 local_irq_save(flags
);
91 mic_tm_regs
= cbe_get_cpu_mic_tm_regs(cpu
);
92 pmd_regs
= cbe_get_cpu_pmd_regs(cpu
);
94 pr_debug("pm register is mapped at %p\n", &pmd_regs
->pmcr
);
95 pr_debug("mic register is mapped at %p\n", &mic_tm_regs
->slow_fast_timer_0
);
97 out_be64(&mic_tm_regs
->slow_fast_timer_0
, MIC_Slow_Fast_Timer_table
[pmode
]);
98 out_be64(&mic_tm_regs
->slow_fast_timer_1
, MIC_Slow_Fast_Timer_table
[pmode
]);
100 out_be64(&mic_tm_regs
->slow_next_timer_0
, MIC_Slow_Next_Timer_table
[pmode
]);
101 out_be64(&mic_tm_regs
->slow_next_timer_1
, MIC_Slow_Next_Timer_table
[pmode
]);
103 value
= in_be64(&pmd_regs
->pmcr
);
104 /* set bits to zero */
105 value
&= 0xFFFFFFFFFFFFFFF8ull
;
106 /* set bits to next pmode */
109 out_be64(&pmd_regs
->pmcr
, value
);
111 /* wait until new pmode appears in status register */
112 value
= in_be64(&pmd_regs
->pmsr
) & 0x07;
113 while(value
!= pmode
) {
115 value
= in_be64(&pmd_regs
->pmsr
) & 0x07;
118 local_irq_restore(flags
);
127 static int cbe_cpufreq_cpu_init (struct cpufreq_policy
*policy
)
131 struct device_node
*cpu
;
133 cpu
= of_get_cpu_node(policy
->cpu
, NULL
);
138 pr_debug("init cpufreq on CPU %d\n", policy
->cpu
);
140 max_freq
= (u32
*) get_property(cpu
, "clock-frequency", NULL
);
145 // we need the freq in kHz
148 pr_debug("max clock-frequency is at %u kHz\n", *max_freq
);
149 pr_debug("initializing frequency table\n");
151 // initialize frequency table
152 for (i
=0; cbe_freqs
[i
].frequency
!=CPUFREQ_TABLE_END
; i
++) {
153 cbe_freqs
[i
].frequency
= *max_freq
/ cbe_freqs
[i
].index
;
154 pr_debug("%d: %d\n", i
, cbe_freqs
[i
].frequency
);
157 policy
->governor
= CPUFREQ_DEFAULT_GOVERNOR
;
158 /* if DEBUG is enabled set_pmode() measures the correct latency of a transition */
159 policy
->cpuinfo
.transition_latency
= 25000;
161 cur_pmode
= get_pmode(policy
->cpu
);
162 pr_debug("current pmode is at %d\n",cur_pmode
);
164 policy
->cur
= cbe_freqs
[cur_pmode
].frequency
;
167 policy
->cpus
= cpu_sibling_map
[policy
->cpu
];
170 cpufreq_frequency_table_get_attr (cbe_freqs
, policy
->cpu
);
172 /* this ensures that policy->cpuinfo_min and policy->cpuinfo_max are set correctly */
173 return cpufreq_frequency_table_cpuinfo (policy
, cbe_freqs
);
176 static int cbe_cpufreq_cpu_exit(struct cpufreq_policy
*policy
)
178 cpufreq_frequency_table_put_attr(policy
->cpu
);
182 static int cbe_cpufreq_verify(struct cpufreq_policy
*policy
)
184 return cpufreq_frequency_table_verify(policy
, cbe_freqs
);
188 static int cbe_cpufreq_target(struct cpufreq_policy
*policy
, unsigned int target_freq
,
189 unsigned int relation
)
192 struct cpufreq_freqs freqs
;
195 cpufreq_frequency_table_target(policy
,
201 freqs
.old
= policy
->cur
;
202 freqs
.new = cbe_freqs
[cbe_pmode_new
].frequency
;
203 freqs
.cpu
= policy
->cpu
;
205 mutex_lock (&cbe_switch_mutex
);
206 cpufreq_notify_transition(&freqs
, CPUFREQ_PRECHANGE
);
208 pr_debug("setting frequency for cpu %d to %d kHz, 1/%d of max frequency\n",
210 cbe_freqs
[cbe_pmode_new
].frequency
,
211 cbe_freqs
[cbe_pmode_new
].index
);
213 rc
= set_pmode(policy
->cpu
, cbe_pmode_new
);
214 cpufreq_notify_transition(&freqs
, CPUFREQ_POSTCHANGE
);
215 mutex_unlock(&cbe_switch_mutex
);
220 static struct cpufreq_driver cbe_cpufreq_driver
= {
221 .verify
= cbe_cpufreq_verify
,
222 .target
= cbe_cpufreq_target
,
223 .init
= cbe_cpufreq_cpu_init
,
224 .exit
= cbe_cpufreq_cpu_exit
,
225 .name
= "cbe-cpufreq",
226 .owner
= THIS_MODULE
,
227 .flags
= CPUFREQ_CONST_LOOPS
,
231 * module init and destoy
234 static int __init
cbe_cpufreq_init(void)
236 return cpufreq_register_driver(&cbe_cpufreq_driver
);
239 static void __exit
cbe_cpufreq_exit(void)
241 cpufreq_unregister_driver(&cbe_cpufreq_driver
);
244 module_init(cbe_cpufreq_init
);
245 module_exit(cbe_cpufreq_exit
);
247 MODULE_LICENSE("GPL");
248 MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");