1 files changed, 173 insertions, 0 deletions

diff --git a/drivers/cpufreq/ppc_cbe_cpufreq.c b/drivers/cpufreq/ppc_cbe_cpufreq.c
new file mode 100644
index 000000000..e3313ce63
--- /dev/null
+++ b/drivers/cpufreq/ppc_cbe_cpufreq.c
@@ -0,0 +1,173 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * cpufreq driver for the cell processor
+ *
+ * (C) Copyright IBM Deutschland Entwicklung GmbH 2005-2007
+ *
+ * Author: Christian Krafft <krafft@de.ibm.com>
+ */
+
+#include <linux/cpufreq.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+
+#include <asm/machdep.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");
+		of_node_put(cpu);
+		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
+
+	policy->freq_table = cbe_freqs;
+	cbe_cpufreq_pmi_policy_init(policy);
+	return 0;
+}
+
+static int cbe_cpufreq_cpu_exit(struct cpufreq_policy *policy)
+{
+	cbe_cpufreq_pmi_policy_exit(policy);
+	return 0;
+}
+
+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,
+	.exit		= cbe_cpufreq_cpu_exit,
+	.name		= "cbe-cpufreq",
+	.flags		= CPUFREQ_CONST_LOOPS,
+};
+
+/*
+ * module init and destoy
+ */
+
+static int __init cbe_cpufreq_init(void)
+{
+	int ret;
+
+	if (!machine_is(cell))
+		return -ENODEV;
+
+	cbe_cpufreq_pmi_init();
+
+	ret = cpufreq_register_driver(&cbe_cpufreq_driver);
+	if (ret)
+		cbe_cpufreq_pmi_exit();
+
+	return ret;
+}
+
+static void __exit cbe_cpufreq_exit(void)
+{
+	cpufreq_unregister_driver(&cbe_cpufreq_driver);
+	cbe_cpufreq_pmi_exit();
+}
+
+module_init(cbe_cpufreq_init);
+module_exit(cbe_cpufreq_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");