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path: root/drivers/cpufreq/qoriq-cpufreq.c
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Diffstat (limited to 'drivers/cpufreq/qoriq-cpufreq.c')
-rw-r--r--drivers/cpufreq/qoriq-cpufreq.c310
1 files changed, 310 insertions, 0 deletions
diff --git a/drivers/cpufreq/qoriq-cpufreq.c b/drivers/cpufreq/qoriq-cpufreq.c
new file mode 100644
index 000000000..573b417e1
--- /dev/null
+++ b/drivers/cpufreq/qoriq-cpufreq.c
@@ -0,0 +1,310 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2013 Freescale Semiconductor, Inc.
+ *
+ * CPU Frequency Scaling driver for Freescale QorIQ SoCs.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/cpufreq.h>
+#include <linux/errno.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>
+#include <linux/platform_device.h>
+
+/**
+ * struct cpu_data
+ * @pclk: the parent clock of cpu
+ * @table: frequency table
+ */
+struct cpu_data {
+ struct clk **pclk;
+ struct cpufreq_frequency_table *table;
+};
+
+/**
+ * struct soc_data - SoC specific data
+ * @flags: SOC_xxx
+ */
+struct soc_data {
+ u32 flags;
+};
+
+static u32 get_bus_freq(void)
+{
+ struct device_node *soc;
+ u32 sysfreq;
+ struct clk *pltclk;
+ int ret;
+
+ /* get platform freq by searching bus-frequency property */
+ soc = of_find_node_by_type(NULL, "soc");
+ if (soc) {
+ ret = of_property_read_u32(soc, "bus-frequency", &sysfreq);
+ of_node_put(soc);
+ if (!ret)
+ return sysfreq;
+ }
+
+ /* get platform freq by its clock name */
+ pltclk = clk_get(NULL, "cg-pll0-div1");
+ if (IS_ERR(pltclk)) {
+ pr_err("%s: can't get bus frequency %ld\n",
+ __func__, PTR_ERR(pltclk));
+ return PTR_ERR(pltclk);
+ }
+
+ return clk_get_rate(pltclk);
+}
+
+static struct clk *cpu_to_clk(int cpu)
+{
+ struct device_node *np;
+ struct clk *clk;
+
+ if (!cpu_present(cpu))
+ return NULL;
+
+ np = of_get_cpu_node(cpu, NULL);
+ if (!np)
+ return NULL;
+
+ clk = of_clk_get(np, 0);
+ of_node_put(np);
+ return clk;
+}
+
+/* traverse cpu nodes to get cpu mask of sharing clock wire */
+static void set_affected_cpus(struct cpufreq_policy *policy)
+{
+ struct cpumask *dstp = policy->cpus;
+ struct clk *clk;
+ int i;
+
+ for_each_present_cpu(i) {
+ clk = cpu_to_clk(i);
+ if (IS_ERR(clk)) {
+ pr_err("%s: no clock for cpu %d\n", __func__, i);
+ continue;
+ }
+
+ if (clk_is_match(policy->clk, clk))
+ cpumask_set_cpu(i, dstp);
+ }
+}
+
+/* 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 qoriq_cpufreq_cpu_init(struct cpufreq_policy *policy)
+{
+ struct device_node *np;
+ int i, count;
+ u32 freq;
+ struct clk *clk;
+ const struct clk_hw *hwclk;
+ struct cpufreq_frequency_table *table;
+ struct cpu_data *data;
+ unsigned int cpu = policy->cpu;
+ u64 u64temp;
+
+ np = of_get_cpu_node(cpu, NULL);
+ if (!np)
+ return -ENODEV;
+
+ data = kzalloc(sizeof(*data), GFP_KERNEL);
+ if (!data)
+ goto err_np;
+
+ policy->clk = of_clk_get(np, 0);
+ if (IS_ERR(policy->clk)) {
+ pr_err("%s: no clock information\n", __func__);
+ goto err_nomem2;
+ }
+
+ hwclk = __clk_get_hw(policy->clk);
+ count = clk_hw_get_num_parents(hwclk);
+
+ data->pclk = kcalloc(count, sizeof(struct clk *), GFP_KERNEL);
+ if (!data->pclk)
+ goto err_nomem2;
+
+ table = kcalloc(count + 1, sizeof(*table), GFP_KERNEL);
+ if (!table)
+ goto err_pclk;
+
+ for (i = 0; i < count; i++) {
+ clk = clk_hw_get_parent_by_index(hwclk, i)->clk;
+ data->pclk[i] = clk;
+ freq = clk_get_rate(clk);
+ 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;
+ policy->freq_table = table;
+ data->table = table;
+
+ /* update ->cpus if we have cluster, no harm if not */
+ set_affected_cpus(policy);
+ policy->driver_data = data;
+
+ /* Minimum transition latency is 12 platform clocks */
+ u64temp = 12ULL * NSEC_PER_SEC;
+ do_div(u64temp, get_bus_freq());
+ policy->cpuinfo.transition_latency = u64temp + 1;
+
+ of_node_put(np);
+
+ return 0;
+
+err_pclk:
+ kfree(data->pclk);
+err_nomem2:
+ kfree(data);
+err_np:
+ of_node_put(np);
+
+ return -ENODEV;
+}
+
+static int qoriq_cpufreq_cpu_exit(struct cpufreq_policy *policy)
+{
+ struct cpu_data *data = policy->driver_data;
+
+ kfree(data->pclk);
+ kfree(data->table);
+ kfree(data);
+ policy->driver_data = NULL;
+
+ return 0;
+}
+
+static int qoriq_cpufreq_target(struct cpufreq_policy *policy,
+ unsigned int index)
+{
+ struct clk *parent;
+ struct cpu_data *data = policy->driver_data;
+
+ parent = data->pclk[data->table[index].driver_data];
+ return clk_set_parent(policy->clk, parent);
+}
+
+static struct cpufreq_driver qoriq_cpufreq_driver = {
+ .name = "qoriq_cpufreq",
+ .flags = CPUFREQ_CONST_LOOPS |
+ CPUFREQ_IS_COOLING_DEV,
+ .init = qoriq_cpufreq_cpu_init,
+ .exit = qoriq_cpufreq_cpu_exit,
+ .verify = cpufreq_generic_frequency_table_verify,
+ .target_index = qoriq_cpufreq_target,
+ .get = cpufreq_generic_get,
+ .attr = cpufreq_generic_attr,
+};
+
+static const struct of_device_id qoriq_cpufreq_blacklist[] = {
+ /* e6500 cannot use cpufreq due to erratum A-008083 */
+ { .compatible = "fsl,b4420-clockgen", },
+ { .compatible = "fsl,b4860-clockgen", },
+ { .compatible = "fsl,t2080-clockgen", },
+ { .compatible = "fsl,t4240-clockgen", },
+ {}
+};
+
+static int qoriq_cpufreq_probe(struct platform_device *pdev)
+{
+ int ret;
+ struct device_node *np;
+
+ np = of_find_matching_node(NULL, qoriq_cpufreq_blacklist);
+ if (np) {
+ of_node_put(np);
+ dev_info(&pdev->dev, "Disabling due to erratum A-008083");
+ return -ENODEV;
+ }
+
+ ret = cpufreq_register_driver(&qoriq_cpufreq_driver);
+ if (ret)
+ return ret;
+
+ dev_info(&pdev->dev, "Freescale QorIQ CPU frequency scaling driver\n");
+ return 0;
+}
+
+static int qoriq_cpufreq_remove(struct platform_device *pdev)
+{
+ cpufreq_unregister_driver(&qoriq_cpufreq_driver);
+
+ return 0;
+}
+
+static struct platform_driver qoriq_cpufreq_platform_driver = {
+ .driver = {
+ .name = "qoriq-cpufreq",
+ },
+ .probe = qoriq_cpufreq_probe,
+ .remove = qoriq_cpufreq_remove,
+};
+module_platform_driver(qoriq_cpufreq_platform_driver);
+
+MODULE_ALIAS("platform:qoriq-cpufreq");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Tang Yuantian <Yuantian.Tang@freescale.com>");
+MODULE_DESCRIPTION("cpufreq driver for Freescale QorIQ series SoCs");