1 /* 2 * cpufreq driver for the cell processor 3 * 4 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005-2007 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/module.h> 25 #include <linux/of_platform.h> 26 27 #include <asm/machdep.h> 28 #include <asm/prom.h> 29 #include <asm/cell-regs.h> 30 31 #include "ppc_cbe_cpufreq.h" 32 33 /* the CBE supports an 8 step frequency scaling */ 34 static struct cpufreq_frequency_table cbe_freqs[] = { 35 {0, 1, 0}, 36 {0, 2, 0}, 37 {0, 3, 0}, 38 {0, 4, 0}, 39 {0, 5, 0}, 40 {0, 6, 0}, 41 {0, 8, 0}, 42 {0, 10, 0}, 43 {0, 0, CPUFREQ_TABLE_END}, 44 }; 45 46 /* 47 * hardware specific functions 48 */ 49 50 static int set_pmode(unsigned int cpu, unsigned int slow_mode) 51 { 52 int rc; 53 54 if (cbe_cpufreq_has_pmi) 55 rc = cbe_cpufreq_set_pmode_pmi(cpu, slow_mode); 56 else 57 rc = cbe_cpufreq_set_pmode(cpu, slow_mode); 58 59 pr_debug("register contains slow mode %d\n", cbe_cpufreq_get_pmode(cpu)); 60 61 return rc; 62 } 63 64 /* 65 * cpufreq functions 66 */ 67 68 static int cbe_cpufreq_cpu_init(struct cpufreq_policy *policy) 69 { 70 struct cpufreq_frequency_table *pos; 71 const u32 *max_freqp; 72 u32 max_freq; 73 int cur_pmode; 74 struct device_node *cpu; 75 76 cpu = of_get_cpu_node(policy->cpu, NULL); 77 78 if (!cpu) 79 return -ENODEV; 80 81 pr_debug("init cpufreq on CPU %d\n", policy->cpu); 82 83 /* 84 * Let's check we can actually get to the CELL regs 85 */ 86 if (!cbe_get_cpu_pmd_regs(policy->cpu) || 87 !cbe_get_cpu_mic_tm_regs(policy->cpu)) { 88 pr_info("invalid CBE regs pointers for cpufreq\n"); 89 return -EINVAL; 90 } 91 92 max_freqp = of_get_property(cpu, "clock-frequency", NULL); 93 94 of_node_put(cpu); 95 96 if (!max_freqp) 97 return -EINVAL; 98 99 /* we need the freq in kHz */ 100 max_freq = *max_freqp / 1000; 101 102 pr_debug("max clock-frequency is at %u kHz\n", max_freq); 103 pr_debug("initializing frequency table\n"); 104 105 /* initialize frequency table */ 106 cpufreq_for_each_entry(pos, cbe_freqs) { 107 pos->frequency = max_freq / pos->driver_data; 108 pr_debug("%d: %d\n", (int)(pos - cbe_freqs), pos->frequency); 109 } 110 111 /* if DEBUG is enabled set_pmode() measures the latency 112 * of a transition */ 113 policy->cpuinfo.transition_latency = 25000; 114 115 cur_pmode = cbe_cpufreq_get_pmode(policy->cpu); 116 pr_debug("current pmode is at %d\n",cur_pmode); 117 118 policy->cur = cbe_freqs[cur_pmode].frequency; 119 120 #ifdef CONFIG_SMP 121 cpumask_copy(policy->cpus, cpu_sibling_mask(policy->cpu)); 122 #endif 123 124 /* this ensures that policy->cpuinfo_min 125 * and policy->cpuinfo_max are set correctly */ 126 return cpufreq_table_validate_and_show(policy, cbe_freqs); 127 } 128 129 static int cbe_cpufreq_target(struct cpufreq_policy *policy, 130 unsigned int cbe_pmode_new) 131 { 132 pr_debug("setting frequency for cpu %d to %d kHz, " \ 133 "1/%d of max frequency\n", 134 policy->cpu, 135 cbe_freqs[cbe_pmode_new].frequency, 136 cbe_freqs[cbe_pmode_new].driver_data); 137 138 return set_pmode(policy->cpu, cbe_pmode_new); 139 } 140 141 static struct cpufreq_driver cbe_cpufreq_driver = { 142 .verify = cpufreq_generic_frequency_table_verify, 143 .target_index = cbe_cpufreq_target, 144 .init = cbe_cpufreq_cpu_init, 145 .name = "cbe-cpufreq", 146 .flags = CPUFREQ_CONST_LOOPS, 147 }; 148 149 /* 150 * module init and destoy 151 */ 152 153 static int __init cbe_cpufreq_init(void) 154 { 155 if (!machine_is(cell)) 156 return -ENODEV; 157 158 return cpufreq_register_driver(&cbe_cpufreq_driver); 159 } 160 161 static void __exit cbe_cpufreq_exit(void) 162 { 163 cpufreq_unregister_driver(&cbe_cpufreq_driver); 164 } 165 166 module_init(cbe_cpufreq_init); 167 module_exit(cbe_cpufreq_exit); 168 169 MODULE_LICENSE("GPL"); 170 MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>"); 171