174 lines
3.6 KiB
C
174 lines
3.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* cpufreq driver for the cell processor
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*
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* (C) Copyright IBM Deutschland Entwicklung GmbH 2005-2007
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*
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* Author: Christian Krafft <krafft@de.ibm.com>
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*/
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#include <linux/cpufreq.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <asm/machdep.h>
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#include <asm/cell-regs.h>
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#include "ppc_cbe_cpufreq.h"
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/* the CBE supports an 8 step frequency scaling */
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static struct cpufreq_frequency_table cbe_freqs[] = {
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{0, 1, 0},
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{0, 2, 0},
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{0, 3, 0},
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{0, 4, 0},
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{0, 5, 0},
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{0, 6, 0},
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{0, 8, 0},
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{0, 10, 0},
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{0, 0, CPUFREQ_TABLE_END},
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};
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/*
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* hardware specific functions
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*/
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static int set_pmode(unsigned int cpu, unsigned int slow_mode)
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{
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int rc;
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if (cbe_cpufreq_has_pmi)
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rc = cbe_cpufreq_set_pmode_pmi(cpu, slow_mode);
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else
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rc = cbe_cpufreq_set_pmode(cpu, slow_mode);
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pr_debug("register contains slow mode %d\n", cbe_cpufreq_get_pmode(cpu));
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return rc;
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}
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/*
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* cpufreq functions
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*/
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static int cbe_cpufreq_cpu_init(struct cpufreq_policy *policy)
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{
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struct cpufreq_frequency_table *pos;
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const u32 *max_freqp;
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u32 max_freq;
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int cur_pmode;
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struct device_node *cpu;
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cpu = of_get_cpu_node(policy->cpu, NULL);
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if (!cpu)
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return -ENODEV;
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pr_debug("init cpufreq on CPU %d\n", policy->cpu);
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/*
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* Let's check we can actually get to the CELL regs
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*/
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if (!cbe_get_cpu_pmd_regs(policy->cpu) ||
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!cbe_get_cpu_mic_tm_regs(policy->cpu)) {
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pr_info("invalid CBE regs pointers for cpufreq\n");
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of_node_put(cpu);
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return -EINVAL;
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}
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max_freqp = of_get_property(cpu, "clock-frequency", NULL);
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of_node_put(cpu);
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if (!max_freqp)
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return -EINVAL;
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/* we need the freq in kHz */
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max_freq = *max_freqp / 1000;
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pr_debug("max clock-frequency is at %u kHz\n", max_freq);
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pr_debug("initializing frequency table\n");
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/* initialize frequency table */
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cpufreq_for_each_entry(pos, cbe_freqs) {
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pos->frequency = max_freq / pos->driver_data;
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pr_debug("%d: %d\n", (int)(pos - cbe_freqs), pos->frequency);
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}
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/* if DEBUG is enabled set_pmode() measures the latency
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* of a transition */
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policy->cpuinfo.transition_latency = 25000;
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cur_pmode = cbe_cpufreq_get_pmode(policy->cpu);
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pr_debug("current pmode is at %d\n",cur_pmode);
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policy->cur = cbe_freqs[cur_pmode].frequency;
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#ifdef CONFIG_SMP
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cpumask_copy(policy->cpus, cpu_sibling_mask(policy->cpu));
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#endif
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policy->freq_table = cbe_freqs;
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cbe_cpufreq_pmi_policy_init(policy);
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return 0;
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}
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static int cbe_cpufreq_cpu_exit(struct cpufreq_policy *policy)
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{
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cbe_cpufreq_pmi_policy_exit(policy);
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return 0;
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}
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static int cbe_cpufreq_target(struct cpufreq_policy *policy,
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unsigned int cbe_pmode_new)
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{
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pr_debug("setting frequency for cpu %d to %d kHz, " \
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"1/%d of max frequency\n",
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policy->cpu,
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cbe_freqs[cbe_pmode_new].frequency,
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cbe_freqs[cbe_pmode_new].driver_data);
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return set_pmode(policy->cpu, cbe_pmode_new);
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}
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static struct cpufreq_driver cbe_cpufreq_driver = {
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.verify = cpufreq_generic_frequency_table_verify,
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.target_index = cbe_cpufreq_target,
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.init = cbe_cpufreq_cpu_init,
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.exit = cbe_cpufreq_cpu_exit,
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.name = "cbe-cpufreq",
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.flags = CPUFREQ_CONST_LOOPS,
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};
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/*
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* module init and destoy
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*/
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static int __init cbe_cpufreq_init(void)
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{
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int ret;
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if (!machine_is(cell))
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return -ENODEV;
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cbe_cpufreq_pmi_init();
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ret = cpufreq_register_driver(&cbe_cpufreq_driver);
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if (ret)
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cbe_cpufreq_pmi_exit();
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return ret;
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}
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static void __exit cbe_cpufreq_exit(void)
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{
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cpufreq_unregister_driver(&cbe_cpufreq_driver);
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cbe_cpufreq_pmi_exit();
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}
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module_init(cbe_cpufreq_init);
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module_exit(cbe_cpufreq_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");
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