1 /* 2 * pmi backend for the cbe_cpufreq driver 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/kernel.h> 24 #include <linux/types.h> 25 #include <linux/timer.h> 26 #include <linux/init.h> 27 #include <linux/of_platform.h> 28 29 #include <asm/processor.h> 30 #include <asm/prom.h> 31 #include <asm/pmi.h> 32 #include <asm/cell-regs.h> 33 34 #ifdef DEBUG 35 #include <asm/time.h> 36 #endif 37 38 #include "ppc_cbe_cpufreq.h" 39 40 static u8 pmi_slow_mode_limit[MAX_CBE]; 41 42 bool cbe_cpufreq_has_pmi = false; 43 EXPORT_SYMBOL_GPL(cbe_cpufreq_has_pmi); 44 45 /* 46 * hardware specific functions 47 */ 48 49 int cbe_cpufreq_set_pmode_pmi(int cpu, unsigned int pmode) 50 { 51 int ret; 52 pmi_message_t pmi_msg; 53 #ifdef DEBUG 54 long time; 55 #endif 56 pmi_msg.type = PMI_TYPE_FREQ_CHANGE; 57 pmi_msg.data1 = cbe_cpu_to_node(cpu); 58 pmi_msg.data2 = pmode; 59 60 #ifdef DEBUG 61 time = jiffies; 62 #endif 63 pmi_send_message(pmi_msg); 64 65 #ifdef DEBUG 66 time = jiffies - time; 67 time = jiffies_to_msecs(time); 68 pr_debug("had to wait %lu ms for a transition using " \ 69 "PMI\n", time); 70 #endif 71 ret = pmi_msg.data2; 72 pr_debug("PMI returned slow mode %d\n", ret); 73 74 return ret; 75 } 76 EXPORT_SYMBOL_GPL(cbe_cpufreq_set_pmode_pmi); 77 78 79 static void cbe_cpufreq_handle_pmi(pmi_message_t pmi_msg) 80 { 81 u8 node, slow_mode; 82 83 BUG_ON(pmi_msg.type != PMI_TYPE_FREQ_CHANGE); 84 85 node = pmi_msg.data1; 86 slow_mode = pmi_msg.data2; 87 88 pmi_slow_mode_limit[node] = slow_mode; 89 90 pr_debug("cbe_handle_pmi: node: %d max_freq: %d\n", node, slow_mode); 91 } 92 93 static int pmi_notifier(struct notifier_block *nb, 94 unsigned long event, void *data) 95 { 96 struct cpufreq_policy *policy = data; 97 struct cpufreq_frequency_table *cbe_freqs = policy->freq_table; 98 u8 node; 99 100 /* Should this really be called for CPUFREQ_ADJUST and CPUFREQ_NOTIFY 101 * policy events?) 102 */ 103 node = cbe_cpu_to_node(policy->cpu); 104 105 pr_debug("got notified, event=%lu, node=%u\n", event, node); 106 107 if (pmi_slow_mode_limit[node] != 0) { 108 pr_debug("limiting node %d to slow mode %d\n", 109 node, pmi_slow_mode_limit[node]); 110 111 cpufreq_verify_within_limits(policy, 0, 112 113 cbe_freqs[pmi_slow_mode_limit[node]].frequency); 114 } 115 116 return 0; 117 } 118 119 static struct notifier_block pmi_notifier_block = { 120 .notifier_call = pmi_notifier, 121 }; 122 123 static struct pmi_handler cbe_pmi_handler = { 124 .type = PMI_TYPE_FREQ_CHANGE, 125 .handle_pmi_message = cbe_cpufreq_handle_pmi, 126 }; 127 128 129 130 static int __init cbe_cpufreq_pmi_init(void) 131 { 132 cbe_cpufreq_has_pmi = pmi_register_handler(&cbe_pmi_handler) == 0; 133 134 if (!cbe_cpufreq_has_pmi) 135 return -ENODEV; 136 137 cpufreq_register_notifier(&pmi_notifier_block, CPUFREQ_POLICY_NOTIFIER); 138 139 return 0; 140 } 141 device_initcall(cbe_cpufreq_pmi_init); 142