/* * cpufreq driver for the cell processor * * (C) Copyright IBM Deutschland Entwicklung GmbH 2005-2007 * * Author: Christian Krafft <krafft@de.ibm.com> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2, or (at your option) * any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include <linux/cpufreq.h> #include <linux/module.h> #include <linux/of_platform.h> #include <asm/machdep.h> #include <asm/prom.h> #include <asm/cell-regs.h> #include "ppc_cbe_cpufreq.h" /* the CBE supports an 8 step frequency scaling */ static struct cpufreq_frequency_table cbe_freqs[] = { {0, 1, 0}, {0, 2, 0}, {0, 3, 0}, {0, 4, 0}, {0, 5, 0}, {0, 6, 0}, {0, 8, 0}, {0, 10, 0}, {0, 0, CPUFREQ_TABLE_END}, }; /* * hardware specific functions */ static int set_pmode(unsigned int cpu, unsigned int slow_mode) { int rc; if (cbe_cpufreq_has_pmi) rc = cbe_cpufreq_set_pmode_pmi(cpu, slow_mode); else rc = cbe_cpufreq_set_pmode(cpu, slow_mode); pr_debug("register contains slow mode %d\n", cbe_cpufreq_get_pmode(cpu)); return rc; } /* * cpufreq functions */ static int cbe_cpufreq_cpu_init(struct cpufreq_policy *policy) { struct cpufreq_frequency_table *pos; const u32 *max_freqp; u32 max_freq; int cur_pmode; struct device_node *cpu; cpu = of_get_cpu_node(policy->cpu, NULL); if (!cpu) return -ENODEV; pr_debug("init cpufreq on CPU %d\n", policy->cpu); /* * Let's check we can actually get to the CELL regs */ if (!cbe_get_cpu_pmd_regs(policy->cpu) || !cbe_get_cpu_mic_tm_regs(policy->cpu)) { pr_info("invalid CBE regs pointers for cpufreq\n"); return -EINVAL; } max_freqp = of_get_property(cpu, "clock-frequency", NULL); of_node_put(cpu); if (!max_freqp) return -EINVAL; /* we need the freq in kHz */ max_freq = *max_freqp / 1000; pr_debug("max clock-frequency is at %u kHz\n", max_freq); pr_debug("initializing frequency table\n"); /* initialize frequency table */ cpufreq_for_each_entry(pos, cbe_freqs) { pos->frequency = max_freq / pos->driver_data; pr_debug("%d: %d\n", (int)(pos - cbe_freqs), pos->frequency); } /* if DEBUG is enabled set_pmode() measures the latency * of a transition */ policy->cpuinfo.transition_latency = 25000; cur_pmode = cbe_cpufreq_get_pmode(policy->cpu); pr_debug("current pmode is at %d\n",cur_pmode); policy->cur = cbe_freqs[cur_pmode].frequency; #ifdef CONFIG_SMP cpumask_copy(policy->cpus, cpu_sibling_mask(policy->cpu)); #endif /* this ensures that policy->cpuinfo_min * and policy->cpuinfo_max are set correctly */ return cpufreq_table_validate_and_show(policy, cbe_freqs); } static int cbe_cpufreq_target(struct cpufreq_policy *policy, unsigned int cbe_pmode_new) { pr_debug("setting frequency for cpu %d to %d kHz, " \ "1/%d of max frequency\n", policy->cpu, cbe_freqs[cbe_pmode_new].frequency, cbe_freqs[cbe_pmode_new].driver_data); return set_pmode(policy->cpu, cbe_pmode_new); } static struct cpufreq_driver cbe_cpufreq_driver = { .verify = cpufreq_generic_frequency_table_verify, .target_index = cbe_cpufreq_target, .init = cbe_cpufreq_cpu_init, .name = "cbe-cpufreq", .flags = CPUFREQ_CONST_LOOPS, }; /* * module init and destoy */ static int __init cbe_cpufreq_init(void) { if (!machine_is(cell)) return -ENODEV; return cpufreq_register_driver(&cbe_cpufreq_driver); } static void __exit cbe_cpufreq_exit(void) { cpufreq_unregister_driver(&cbe_cpufreq_driver); } module_init(cbe_cpufreq_init); module_exit(cbe_cpufreq_exit); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");