--- /dev/null
+/*
+ * Copyright 2013 Freescale Semiconductor, Inc.
+ *
+ * CPU Frequency Scaling driver for Freescale PowerPC corenet SoCs.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/clk.h>
+#include <linux/cpufreq.h>
+#include <linux/errno.h>
+#include <sysdev/fsl_soc.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+#include <linux/smp.h>
+
+/**
+ * struct cpu_data - per CPU data struct
+ * @clk: the clk of CPU
+ * @parent: the parent node of cpu clock
+ * @table: frequency table
+ */
+struct cpu_data {
+ struct clk *clk;
+ struct device_node *parent;
+ struct cpufreq_frequency_table *table;
+};
+
+/**
+ * struct soc_data - SoC specific data
+ * @freq_mask: mask the disallowed frequencies
+ * @flag: unique flags
+ */
+struct soc_data {
+ u32 freq_mask[4];
+ u32 flag;
+};
+
+#define FREQ_MASK 1
+/* see hardware specification for the allowed frqeuencies */
+static const struct soc_data sdata[] = {
+ { /* used by p2041 and p3041 */
+ .freq_mask = {0x8, 0x8, 0x2, 0x2},
+ .flag = FREQ_MASK,
+ },
+ { /* used by p5020 */
+ .freq_mask = {0x8, 0x2},
+ .flag = FREQ_MASK,
+ },
+ { /* used by p4080, p5040 */
+ .freq_mask = {0},
+ .flag = 0,
+ },
+};
+
+/*
+ * the minimum allowed core frequency, in Hz
+ * for chassis v1.0, >= platform frequency
+ * for chassis v2.0, >= platform frequency / 2
+ */
+static u32 min_cpufreq;
+static const u32 *fmask;
+
+/* serialize frequency changes */
+static DEFINE_MUTEX(cpufreq_lock);
+static DEFINE_PER_CPU(struct cpu_data *, cpu_data);
+
+/* cpumask in a cluster */
+static DEFINE_PER_CPU(cpumask_var_t, cpu_mask);
+
+#ifndef CONFIG_SMP
+static inline const struct cpumask *cpu_core_mask(int cpu)
+{
+ return cpumask_of(0);
+}
+#endif
+
+static unsigned int corenet_cpufreq_get_speed(unsigned int cpu)
+{
+ struct cpu_data *data = per_cpu(cpu_data, cpu);
+
+ return clk_get_rate(data->clk) / 1000;
+}
+
+/* reduce the duplicated frequencies in frequency table */
+static void freq_table_redup(struct cpufreq_frequency_table *freq_table,
+ int count)
+{
+ int i, j;
+
+ for (i = 1; i < count; i++) {
+ for (j = 0; j < i; j++) {
+ if (freq_table[j].frequency == CPUFREQ_ENTRY_INVALID ||
+ freq_table[j].frequency !=
+ freq_table[i].frequency)
+ continue;
+
+ freq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
+ break;
+ }
+ }
+}
+
+/* sort the frequencies in frequency table in descenting order */
+static void freq_table_sort(struct cpufreq_frequency_table *freq_table,
+ int count)
+{
+ int i, j, ind;
+ unsigned int freq, max_freq;
+ struct cpufreq_frequency_table table;
+ for (i = 0; i < count - 1; i++) {
+ max_freq = freq_table[i].frequency;
+ ind = i;
+ for (j = i + 1; j < count; j++) {
+ freq = freq_table[j].frequency;
+ if (freq == CPUFREQ_ENTRY_INVALID ||
+ freq <= max_freq)
+ continue;
+ ind = j;
+ max_freq = freq;
+ }
+
+ if (ind != i) {
+ /* exchange the frequencies */
+ table.driver_data = freq_table[i].driver_data;
+ table.frequency = freq_table[i].frequency;
+ freq_table[i].driver_data = freq_table[ind].driver_data;
+ freq_table[i].frequency = freq_table[ind].frequency;
+ freq_table[ind].driver_data = table.driver_data;
+ freq_table[ind].frequency = table.frequency;
+ }
+ }
+}
+
+static int corenet_cpufreq_cpu_init(struct cpufreq_policy *policy)
+{
+ struct device_node *np;
+ int i, count, ret;
+ u32 freq, mask;
+ struct clk *clk;
+ struct cpufreq_frequency_table *table;
+ struct cpu_data *data;
+ unsigned int cpu = policy->cpu;
+
+ np = of_get_cpu_node(cpu, NULL);
+ if (!np)
+ return -ENODEV;
+
+ data = kzalloc(sizeof(*data), GFP_KERNEL);
+ if (!data) {
+ pr_err("%s: no memory\n", __func__);
+ goto err_np;
+ }
+
+ data->clk = of_clk_get(np, 0);
+ if (IS_ERR(data->clk)) {
+ pr_err("%s: no clock information\n", __func__);
+ goto err_nomem2;
+ }
+
+ data->parent = of_parse_phandle(np, "clocks", 0);
+ if (!data->parent) {
+ pr_err("%s: could not get clock information\n", __func__);
+ goto err_nomem2;
+ }
+
+ count = of_property_count_strings(data->parent, "clock-names");
+ table = kcalloc(count + 1, sizeof(*table), GFP_KERNEL);
+ if (!table) {
+ pr_err("%s: no memory\n", __func__);
+ goto err_node;
+ }
+
+ if (fmask)
+ mask = fmask[get_hard_smp_processor_id(cpu)];
+ else
+ mask = 0x0;
+
+ for (i = 0; i < count; i++) {
+ clk = of_clk_get(data->parent, i);
+ freq = clk_get_rate(clk);
+ /*
+ * the clock is valid if its frequency is not masked
+ * and large than minimum allowed frequency.
+ */
+ if (freq < min_cpufreq || (mask & (1 << i)))
+ table[i].frequency = CPUFREQ_ENTRY_INVALID;
+ else
+ table[i].frequency = freq / 1000;
+ table[i].driver_data = i;
+ }
+ freq_table_redup(table, count);
+ freq_table_sort(table, count);
+ table[i].frequency = CPUFREQ_TABLE_END;
+
+ /* set the min and max frequency properly */
+ ret = cpufreq_frequency_table_cpuinfo(policy, table);
+ if (ret) {
+ pr_err("invalid frequency table: %d\n", ret);
+ goto err_nomem1;
+ }
+
+ data->table = table;
+ per_cpu(cpu_data, cpu) = data;
+
+ /* update ->cpus if we have cluster, no harm if not */
+ cpumask_copy(policy->cpus, per_cpu(cpu_mask, cpu));
+ for_each_cpu(i, per_cpu(cpu_mask, cpu))
+ per_cpu(cpu_data, i) = data;
+
+ policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
+ policy->cur = corenet_cpufreq_get_speed(policy->cpu);
+
+ cpufreq_frequency_table_get_attr(table, cpu);
+ of_node_put(np);
+
+ return 0;
+
+err_nomem1:
+ kfree(table);
+err_node:
+ of_node_put(data->parent);
+err_nomem2:
+ per_cpu(cpu_data, cpu) = NULL;
+ kfree(data);
+err_np:
+ of_node_put(np);
+
+ return -ENODEV;
+}
+
+static int __exit corenet_cpufreq_cpu_exit(struct cpufreq_policy *policy)
+{
+ struct cpu_data *data = per_cpu(cpu_data, policy->cpu);
+ unsigned int cpu;
+
+ cpufreq_frequency_table_put_attr(policy->cpu);
+ of_node_put(data->parent);
+ kfree(data->table);
+ kfree(data);
+
+ for_each_cpu(cpu, per_cpu(cpu_mask, policy->cpu))
+ per_cpu(cpu_data, cpu) = NULL;
+
+ return 0;
+}
+
+static int corenet_cpufreq_verify(struct cpufreq_policy *policy)
+{
+ struct cpufreq_frequency_table *table =
+ per_cpu(cpu_data, policy->cpu)->table;
+
+ return cpufreq_frequency_table_verify(policy, table);
+}
+
+static int corenet_cpufreq_target(struct cpufreq_policy *policy,
+ unsigned int target_freq, unsigned int relation)
+{
+ struct cpufreq_freqs freqs;
+ unsigned int new;
+ struct clk *parent;
+ int ret;
+ struct cpu_data *data = per_cpu(cpu_data, policy->cpu);
+
+ cpufreq_frequency_table_target(policy, data->table,
+ target_freq, relation, &new);
+
+ if (policy->cur == data->table[new].frequency)
+ return 0;
+
+ freqs.old = policy->cur;
+ freqs.new = data->table[new].frequency;
+
+ mutex_lock(&cpufreq_lock);
+ cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
+
+ parent = of_clk_get(data->parent, data->table[new].driver_data);
+ ret = clk_set_parent(data->clk, parent);
+ if (ret)
+ freqs.new = freqs.old;
+
+ cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
+ mutex_unlock(&cpufreq_lock);
+
+ return ret;
+}
+
+static struct freq_attr *corenet_cpufreq_attr[] = {
+ &cpufreq_freq_attr_scaling_available_freqs,
+ NULL,
+};
+
+static struct cpufreq_driver ppc_corenet_cpufreq_driver = {
+ .name = "ppc_cpufreq",
+ .owner = THIS_MODULE,
+ .flags = CPUFREQ_CONST_LOOPS,
+ .init = corenet_cpufreq_cpu_init,
+ .exit = __exit_p(corenet_cpufreq_cpu_exit),
+ .verify = corenet_cpufreq_verify,
+ .target = corenet_cpufreq_target,
+ .get = corenet_cpufreq_get_speed,
+ .attr = corenet_cpufreq_attr,
+};
+
+static const struct of_device_id node_matches[] __initdata = {
+ { .compatible = "fsl,p2041-clockgen", .data = &sdata[0], },
+ { .compatible = "fsl,p3041-clockgen", .data = &sdata[0], },
+ { .compatible = "fsl,p5020-clockgen", .data = &sdata[1], },
+ { .compatible = "fsl,p4080-clockgen", .data = &sdata[2], },
+ { .compatible = "fsl,p5040-clockgen", .data = &sdata[2], },
+ { .compatible = "fsl,qoriq-clockgen-2.0", },
+ {}
+};
+
+static int __init ppc_corenet_cpufreq_init(void)
+{
+ int ret;
+ struct device_node *np;
+ const struct of_device_id *match;
+ const struct soc_data *data;
+ unsigned int cpu;
+
+ np = of_find_matching_node(NULL, node_matches);
+ if (!np)
+ return -ENODEV;
+
+ for_each_possible_cpu(cpu) {
+ if (!alloc_cpumask_var(&per_cpu(cpu_mask, cpu), GFP_KERNEL))
+ goto err_mask;
+ cpumask_copy(per_cpu(cpu_mask, cpu), cpu_core_mask(cpu));
+ }
+
+ match = of_match_node(node_matches, np);
+ data = match->data;
+ if (data) {
+ if (data->flag)
+ fmask = data->freq_mask;
+ min_cpufreq = fsl_get_sys_freq();
+ } else {
+ min_cpufreq = fsl_get_sys_freq() / 2;
+ }
+
+ of_node_put(np);
+
+ ret = cpufreq_register_driver(&ppc_corenet_cpufreq_driver);
+ if (!ret)
+ pr_info("Freescale PowerPC corenet CPU frequency scaling driver\n");
+
+ return ret;
+
+err_mask:
+ for_each_possible_cpu(cpu)
+ free_cpumask_var(per_cpu(cpu_mask, cpu));
+
+ return -ENOMEM;
+}
+module_init(ppc_corenet_cpufreq_init);
+
+static void __exit ppc_corenet_cpufreq_exit(void)
+{
+ unsigned int cpu;
+
+ for_each_possible_cpu(cpu)
+ free_cpumask_var(per_cpu(cpu_mask, cpu));
+
+ cpufreq_unregister_driver(&ppc_corenet_cpufreq_driver);
+}
+module_exit(ppc_corenet_cpufreq_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Tang Yuantian <Yuantian.Tang@freescale.com>");
+MODULE_DESCRIPTION("cpufreq driver for Freescale e500mc series SoCs");
projects / linux-imx.git / commitdiff