--- /dev/null
+/*
+ * 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"
+
+static DEFINE_MUTEX(cbe_switch_mutex);
+
+
+/* the CBE supports an 8 step frequency scaling */
+static struct cpufreq_frequency_table cbe_freqs[] = {
+ {1, 0},
+ {2, 0},
+ {3, 0},
+ {4, 0},
+ {5, 0},
+ {6, 0},
+ {8, 0},
+ {10, 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)
+{
+ const u32 *max_freqp;
+ u32 max_freq;
+ int i, 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 */
+ for (i=0; cbe_freqs[i].frequency!=CPUFREQ_TABLE_END; i++) {
+ cbe_freqs[i].frequency = max_freq / cbe_freqs[i].index;
+ pr_debug("%d: %d\n", i, cbe_freqs[i].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
+
+ cpufreq_frequency_table_get_attr(cbe_freqs, policy->cpu);
+
+ /* this ensures that policy->cpuinfo_min
+ * and policy->cpuinfo_max are set correctly */
+ return cpufreq_frequency_table_cpuinfo(policy, cbe_freqs);
+}
+
+static int cbe_cpufreq_cpu_exit(struct cpufreq_policy *policy)
+{
+ cpufreq_frequency_table_put_attr(policy->cpu);
+ return 0;
+}
+
+static int cbe_cpufreq_verify(struct cpufreq_policy *policy)
+{
+ return cpufreq_frequency_table_verify(policy, cbe_freqs);
+}
+
+static int cbe_cpufreq_target(struct cpufreq_policy *policy,
+ unsigned int target_freq,
+ unsigned int relation)
+{
+ int rc;
+ struct cpufreq_freqs freqs;
+ unsigned int cbe_pmode_new;
+
+ cpufreq_frequency_table_target(policy,
+ cbe_freqs,
+ target_freq,
+ relation,
+ &cbe_pmode_new);
+
+ freqs.old = policy->cur;
+ freqs.new = cbe_freqs[cbe_pmode_new].frequency;
+
+ mutex_lock(&cbe_switch_mutex);
+ cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
+
+ 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].index);
+
+ rc = set_pmode(policy->cpu, cbe_pmode_new);
+
+ cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
+ mutex_unlock(&cbe_switch_mutex);
+
+ return rc;
+}
+
+static struct cpufreq_driver cbe_cpufreq_driver = {
+ .verify = cbe_cpufreq_verify,
+ .target = cbe_cpufreq_target,
+ .init = cbe_cpufreq_cpu_init,
+ .exit = cbe_cpufreq_cpu_exit,
+ .name = "cbe-cpufreq",
+ .owner = THIS_MODULE,
+ .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>");
projects / firefly-linux-kernel-4.4.55.git / blobdiff