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36ca4ba4 CK |
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/processor.h> | |
29 | #include <asm/prom.h> | |
30 | #include <asm/time.h> | |
31 | ||
32 | #include "cbe_regs.h" | |
33 | ||
34 | static DEFINE_MUTEX(cbe_switch_mutex); | |
35 | ||
36 | ||
37 | /* the CBE supports an 8 step frequency scaling */ | |
38 | static struct cpufreq_frequency_table cbe_freqs[] = { | |
39 | {1, 0}, | |
40 | {2, 0}, | |
41 | {3, 0}, | |
42 | {4, 0}, | |
43 | {5, 0}, | |
44 | {6, 0}, | |
45 | {8, 0}, | |
46 | {10, 0}, | |
47 | {0, CPUFREQ_TABLE_END}, | |
48 | }; | |
49 | ||
50 | /* to write to MIC register */ | |
51 | static u64 MIC_Slow_Fast_Timer_table[] = { | |
52 | [0 ... 7] = 0x007fc00000000000ull, | |
53 | }; | |
54 | ||
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, | |
65 | }; | |
66 | ||
67 | /* | |
68 | * hardware specific functions | |
69 | */ | |
70 | ||
71 | static int get_pmode(int cpu) | |
72 | { | |
73 | int ret; | |
74 | struct cbe_pmd_regs __iomem *pmd_regs; | |
75 | ||
76 | pmd_regs = cbe_get_cpu_pmd_regs(cpu); | |
77 | ret = in_be64(&pmd_regs->pmsr) & 0x07; | |
78 | ||
79 | return ret; | |
80 | } | |
81 | ||
82 | static int set_pmode(int cpu, unsigned int pmode) | |
83 | { | |
84 | struct cbe_pmd_regs __iomem *pmd_regs; | |
85 | struct cbe_mic_tm_regs __iomem *mic_tm_regs; | |
86 | u64 flags; | |
87 | u64 value; | |
88 | ||
89 | local_irq_save(flags); | |
90 | ||
91 | mic_tm_regs = cbe_get_cpu_mic_tm_regs(cpu); | |
92 | pmd_regs = cbe_get_cpu_pmd_regs(cpu); | |
93 | ||
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); | |
96 | ||
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]); | |
99 | ||
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]); | |
102 | ||
103 | value = in_be64(&pmd_regs->pmcr); | |
104 | /* set bits to zero */ | |
105 | value &= 0xFFFFFFFFFFFFFFF8ull; | |
106 | /* set bits to next pmode */ | |
107 | value |= pmode; | |
108 | ||
109 | out_be64(&pmd_regs->pmcr, value); | |
110 | ||
111 | /* wait until new pmode appears in status register */ | |
112 | value = in_be64(&pmd_regs->pmsr) & 0x07; | |
113 | while(value != pmode) { | |
114 | cpu_relax(); | |
115 | value = in_be64(&pmd_regs->pmsr) & 0x07; | |
116 | } | |
117 | ||
118 | local_irq_restore(flags); | |
119 | ||
120 | return 0; | |
121 | } | |
122 | ||
123 | /* | |
124 | * cpufreq functions | |
125 | */ | |
126 | ||
127 | static int cbe_cpufreq_cpu_init (struct cpufreq_policy *policy) | |
128 | { | |
9c1a2bae SR |
129 | const u32 *max_freqp; |
130 | u32 max_freq; | |
36ca4ba4 CK |
131 | int i, cur_pmode; |
132 | struct device_node *cpu; | |
133 | ||
134 | cpu = of_get_cpu_node(policy->cpu, NULL); | |
135 | ||
136 | if(!cpu) | |
137 | return -ENODEV; | |
138 | ||
139 | pr_debug("init cpufreq on CPU %d\n", policy->cpu); | |
140 | ||
9c1a2bae | 141 | max_freqp = of_get_property(cpu, "clock-frequency", NULL); |
36ca4ba4 | 142 | |
9c1a2bae | 143 | if (!max_freqp) |
36ca4ba4 CK |
144 | return -EINVAL; |
145 | ||
146 | // we need the freq in kHz | |
9c1a2bae | 147 | max_freq = *max_freqp / 1000; |
36ca4ba4 | 148 | |
9c1a2bae | 149 | pr_debug("max clock-frequency is at %u kHz\n", max_freq); |
36ca4ba4 CK |
150 | pr_debug("initializing frequency table\n"); |
151 | ||
152 | // initialize frequency table | |
153 | for (i=0; cbe_freqs[i].frequency!=CPUFREQ_TABLE_END; i++) { | |
9c1a2bae | 154 | cbe_freqs[i].frequency = max_freq / cbe_freqs[i].index; |
36ca4ba4 CK |
155 | pr_debug("%d: %d\n", i, cbe_freqs[i].frequency); |
156 | } | |
157 | ||
158 | policy->governor = CPUFREQ_DEFAULT_GOVERNOR; | |
159 | /* if DEBUG is enabled set_pmode() measures the correct latency of a transition */ | |
160 | policy->cpuinfo.transition_latency = 25000; | |
161 | ||
162 | cur_pmode = get_pmode(policy->cpu); | |
163 | pr_debug("current pmode is at %d\n",cur_pmode); | |
164 | ||
165 | policy->cur = cbe_freqs[cur_pmode].frequency; | |
166 | ||
167 | #ifdef CONFIG_SMP | |
168 | policy->cpus = cpu_sibling_map[policy->cpu]; | |
169 | #endif | |
170 | ||
171 | cpufreq_frequency_table_get_attr (cbe_freqs, policy->cpu); | |
172 | ||
173 | /* this ensures that policy->cpuinfo_min and policy->cpuinfo_max are set correctly */ | |
174 | return cpufreq_frequency_table_cpuinfo (policy, cbe_freqs); | |
175 | } | |
176 | ||
177 | static int cbe_cpufreq_cpu_exit(struct cpufreq_policy *policy) | |
178 | { | |
179 | cpufreq_frequency_table_put_attr(policy->cpu); | |
180 | return 0; | |
181 | } | |
182 | ||
183 | static int cbe_cpufreq_verify(struct cpufreq_policy *policy) | |
184 | { | |
185 | return cpufreq_frequency_table_verify(policy, cbe_freqs); | |
186 | } | |
187 | ||
188 | ||
189 | static int cbe_cpufreq_target(struct cpufreq_policy *policy, unsigned int target_freq, | |
190 | unsigned int relation) | |
191 | { | |
192 | int rc; | |
193 | struct cpufreq_freqs freqs; | |
194 | int cbe_pmode_new; | |
195 | ||
196 | cpufreq_frequency_table_target(policy, | |
197 | cbe_freqs, | |
198 | target_freq, | |
199 | relation, | |
200 | &cbe_pmode_new); | |
201 | ||
202 | freqs.old = policy->cur; | |
203 | freqs.new = cbe_freqs[cbe_pmode_new].frequency; | |
204 | freqs.cpu = policy->cpu; | |
205 | ||
206 | mutex_lock (&cbe_switch_mutex); | |
207 | cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); | |
208 | ||
209 | pr_debug("setting frequency for cpu %d to %d kHz, 1/%d of max frequency\n", | |
210 | policy->cpu, | |
211 | cbe_freqs[cbe_pmode_new].frequency, | |
212 | cbe_freqs[cbe_pmode_new].index); | |
213 | ||
214 | rc = set_pmode(policy->cpu, cbe_pmode_new); | |
215 | cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); | |
216 | mutex_unlock(&cbe_switch_mutex); | |
217 | ||
218 | return rc; | |
219 | } | |
220 | ||
221 | static struct cpufreq_driver cbe_cpufreq_driver = { | |
222 | .verify = cbe_cpufreq_verify, | |
223 | .target = cbe_cpufreq_target, | |
224 | .init = cbe_cpufreq_cpu_init, | |
225 | .exit = cbe_cpufreq_cpu_exit, | |
226 | .name = "cbe-cpufreq", | |
227 | .owner = THIS_MODULE, | |
228 | .flags = CPUFREQ_CONST_LOOPS, | |
229 | }; | |
230 | ||
231 | /* | |
232 | * module init and destoy | |
233 | */ | |
234 | ||
235 | static int __init cbe_cpufreq_init(void) | |
236 | { | |
237 | return cpufreq_register_driver(&cbe_cpufreq_driver); | |
238 | } | |
239 | ||
240 | static void __exit cbe_cpufreq_exit(void) | |
241 | { | |
242 | cpufreq_unregister_driver(&cbe_cpufreq_driver); | |
243 | } | |
244 | ||
245 | module_init(cbe_cpufreq_init); | |
246 | module_exit(cbe_cpufreq_exit); | |
247 | ||
248 | MODULE_LICENSE("GPL"); | |
249 | MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>"); |