The CPUfreq HW present in some QCOM chipsets offloads the steps necessary
for changing the frequency of CPUs. The driver implements the cpufreq
driver interface for this hardware engine.
Signed-off-by: Saravana Kannan <skannan@xxxxxxxxxxxxxx>
Signed-off-by: Taniya Das <tdas@xxxxxxxxxxxxxx>
---
drivers/cpufreq/Kconfig.arm | 10 ++
drivers/cpufreq/Makefile | 1 +
drivers/cpufreq/qcom-cpufreq-hw.c | 344 ++++++++++++++++++++++++++++++++++++++
3 files changed, 355 insertions(+)
create mode 100644 drivers/cpufreq/qcom-cpufreq-hw.c
diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
index 52f5f1a..141ec3e 100644
--- a/drivers/cpufreq/Kconfig.arm
+++ b/drivers/cpufreq/Kconfig.arm
@@ -312,3 +312,13 @@ config ARM_PXA2xx_CPUFREQ
This add the CPUFreq driver support for Intel PXA2xx SOCs.
If in doubt, say N.
+
+config ARM_QCOM_CPUFREQ_HW
+ bool "QCOM CPUFreq HW driver"
+ help
+ Support for the CPUFreq HW driver.
+ Some QCOM chipsets have a HW engine to offload the steps
+ necessary for changing the frequency of the CPUs. Firmware loaded
+ in this engine exposes a programming interafce to the High-level OS.
+ The driver implements the cpufreq driver interface for this HW engine.
+ Say Y if you want to support CPUFreq HW.
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index fb4a2ec..1226a3e 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -86,6 +86,7 @@ obj-$(CONFIG_ARM_TEGRA124_CPUFREQ) += tegra124-cpufreq.o
obj-$(CONFIG_ARM_TEGRA186_CPUFREQ) += tegra186-cpufreq.o
obj-$(CONFIG_ARM_TI_CPUFREQ) += ti-cpufreq.o
obj-$(CONFIG_ARM_VEXPRESS_SPC_CPUFREQ) += vexpress-spc-cpufreq.o
+obj-$(CONFIG_ARM_QCOM_CPUFREQ_HW) += qcom-cpufreq-hw.o
##################################################################################
diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c
new file mode 100644
index 0000000..fa25a95
--- /dev/null
+++ b/drivers/cpufreq/qcom-cpufreq-hw.c
@@ -0,0 +1,344 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2018, The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/cpufreq.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+
+#define INIT_RATE 300000000UL
+#define XO_RATE 19200000UL
+#define LUT_MAX_ENTRIES 40U
+#define CORE_COUNT_VAL(val) (((val) & (GENMASK(18, 16))) >> 16)
+#define LUT_ROW_SIZE 32
+
+enum {
+ REG_ENABLE,
+ REG_LUT_TABLE,
+ REG_PERF_STATE,
+
+ REG_ARRAY_SIZE,
+};
+
+struct cpufreq_qcom {
+ struct cpufreq_frequency_table *table;
+ struct device *dev;
+ const u16 *reg_offset;
+ void __iomem *base;
+ cpumask_t related_cpus;
+ unsigned int max_cores;
+};
+
+static u16 cpufreq_qcom_std_offsets[REG_ARRAY_SIZE] = {
+ [REG_ENABLE] = 0x0,
+ [REG_LUT_TABLE] = 0x110,
+ [REG_PERF_STATE] = 0x920,
+};
+
+static struct cpufreq_qcom *qcom_freq_domain_map[NR_CPUS];
+
+static int
+qcom_cpufreq_hw_target_index(struct cpufreq_policy *policy,
+ unsigned int index)
+{
+ struct cpufreq_qcom *c = policy->driver_data;
+ unsigned int offset = c->reg_offset[REG_PERF_STATE];
+
+ writel_relaxed(index, c->base + offset);
+
+ return 0;
+}
+
+static unsigned int qcom_cpufreq_hw_get(unsigned int cpu)
+{
+ struct cpufreq_qcom *c;
+ struct cpufreq_policy *policy;
+ unsigned int index, offset;
+
+ policy = cpufreq_cpu_get_raw(cpu);
+ if (!policy)
+ return 0;
+
+ c = policy->driver_data;
+ offset = c->reg_offset[REG_PERF_STATE];
+
+ index = readl_relaxed(c->base + offset);
+ index = min(index, LUT_MAX_ENTRIES - 1);
+
+ return policy->freq_table[index].frequency;
+}
+
+static unsigned int
+qcom_cpufreq_hw_fast_switch(struct cpufreq_policy *policy,
+ unsigned int target_freq)
+{
+ struct cpufreq_qcom *c = policy->driver_data;
+ unsigned int offset;
+ int index;
+
+ index = cpufreq_table_find_index_l(policy, target_freq);
+ if (index < 0)
+ return 0;
+
+ offset = c->reg_offset[REG_PERF_STATE];
+
+ writel_relaxed(index, c->base + offset);
+
+ return policy->freq_table[index].frequency;
+}
+
+static int qcom_cpufreq_hw_cpu_init(struct cpufreq_policy *policy)
+{
+ struct cpufreq_qcom *c;
+
+ c = qcom_freq_domain_map[policy->cpu];
+ if (!c) {
+ pr_err("No scaling support for CPU%d\n", policy->cpu);
+ return -ENODEV;
+ }
+
+ cpumask_copy(policy->cpus, &c->related_cpus);
+
+ policy->fast_switch_possible = true;
+ policy->freq_table = c->table;
+ policy->driver_data = c;
+
+ return 0;
+}
+
+static struct freq_attr *qcom_cpufreq_hw_attr[] = {
+ &cpufreq_freq_attr_scaling_available_freqs,
+ &cpufreq_freq_attr_scaling_boost_freqs,
+ NULL
+};
+
+static struct cpufreq_driver cpufreq_qcom_hw_driver = {
+ .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK |
+ CPUFREQ_HAVE_GOVERNOR_PER_POLICY,
+ .verify = cpufreq_generic_frequency_table_verify,
+ .target_index = qcom_cpufreq_hw_target_index,
+ .get = qcom_cpufreq_hw_get,
+ .init = qcom_cpufreq_hw_cpu_init,
+ .fast_switch = qcom_cpufreq_hw_fast_switch,
+ .name = "qcom-cpufreq-hw",
+ .attr = qcom_cpufreq_hw_attr,
+ .boost_enabled = true,
+};
+
+static int qcom_read_lut(struct platform_device *pdev,
+ struct cpufreq_qcom *c)
+{
+ struct device *dev = &pdev->dev;
+ unsigned int offset;
+ u32 data, src, lval, i, core_count, prev_cc, prev_freq, cur_freq;
+
+ c->table = devm_kcalloc(dev, LUT_MAX_ENTRIES + 1,
+ sizeof(*c->table), GFP_KERNEL);
+ if (!c->table)
+ return -ENOMEM;
+
+ offset = c->reg_offset[REG_LUT_TABLE];
+
+ for (i = 0; i < LUT_MAX_ENTRIES; i++) {
+ data = readl_relaxed(c->base + offset + i * LUT_ROW_SIZE);
+ src = ((data & GENMASK(31, 30)) >> 30);
+ lval = (data & GENMASK(7, 0));
+ core_count = CORE_COUNT_VAL(data);
+
+ if (src == 0)
+ c->table[i].frequency = INIT_RATE / 1000;
+ else
+ c->table[i].frequency = XO_RATE * lval / 1000;
+
+ cur_freq = c->table[i].frequency;
+
+ dev_dbg(dev, "index=%d freq=%d, core_count %d\n",
+ i, c->table[i].frequency, core_count);
+
+ if (core_count != c->max_cores)
+ cur_freq = CPUFREQ_ENTRY_INVALID;
+
+ /*
+ * Two of the same frequencies with the same core counts means
+ * end of table.
+ */
+ if (i > 0 && c->table[i - 1].frequency ==
+ c->table[i].frequency && prev_cc == core_count) {
+ struct cpufreq_frequency_table *prev = &c->table[i - 1];
+
+ if (prev_freq == CPUFREQ_ENTRY_INVALID)
+ prev->flags = CPUFREQ_BOOST_FREQ;
+ break;
+ }
+ prev_cc = core_count;
+ prev_freq = cur_freq;
+ }
+
+ c->table[i].frequency = CPUFREQ_TABLE_END;
+
+ return 0;
+}
+
+static int qcom_get_related_cpus(struct device_node *np, struct cpumask *m)
+{
+ struct device_node *cpu_np, *freq_np;
+ int cpu;
+
+ for_each_possible_cpu(cpu) {
+ cpu_np = of_cpu_device_node_get(cpu);
+ if (!cpu_np)
+ continue;
+ freq_np = of_parse_phandle(cpu_np, "qcom,freq-domain", 0);
+ if (!freq_np) {
+ of_node_put(cpu_np);
+ continue;
+ }
+ if (freq_np == np)
+ cpumask_set_cpu(cpu, m);
+
+ of_node_put(cpu_np);
+ }
+
+ return 0;
+}
+
+static int qcom_cpu_resources_init(struct platform_device *pdev,
+ struct device_node *np, unsigned int cpu)
+{
+ struct cpufreq_qcom *c;
+ struct resource res;
+ struct device *dev = &pdev->dev;
+ unsigned int offset, cpu_r;
+ int ret;
+
+ c = devm_kzalloc(dev, sizeof(*c), GFP_KERNEL);
+ if (!c)
+ return -ENOMEM;
+
+ c->reg_offset = of_device_get_match_data(&pdev->dev);
+ if (!c->reg_offset)
+ return -EINVAL;
+
+ if (of_address_to_resource(np, 0, &res))
+ return -ENOMEM;
+
+ c->base = devm_ioremap(dev, res.start, resource_size(&res));
+ if (!c->base) {
+ dev_err(dev, "Unable to map %s base\n", np->name);
+ return -ENOMEM;
+ }
+
+ offset = c->reg_offset[REG_ENABLE];
+
+ /* HW should be in enabled state to proceed */
+ if (!(readl_relaxed(c->base + offset) & 0x1)) {
+ dev_err(dev, "%s cpufreq hardware not enabled\n", np->name);
+ return -ENODEV;
+ }
+
+ ret = qcom_get_related_cpus(np, &c->related_cpus);
+ if (ret) {
+ dev_err(dev, "%s failed to get related CPUs\n", np->name);
+ return ret;
+ }
+
+ c->max_cores = cpumask_weight(&c->related_cpus);
+ if (!c->max_cores)
+ return -ENOENT;
+
+ ret = qcom_read_lut(pdev, c);
+ if (ret) {
+ dev_err(dev, "%s failed to read LUT\n", np->name);
+ return ret;
+ }
+
+ qcom_freq_domain_map[cpu] = c;
+
+ /* Related CPUs to keep a single copy */
+ cpu_r = cpumask_first(&c->related_cpus);
+ if (cpu != cpu_r) {
+ qcom_freq_domain_map[cpu] = qcom_freq_domain_map[cpu_r];
+ devm_kfree(dev, c);
+ }
+
+ return 0;
+}
+
+static int qcom_resources_init(struct platform_device *pdev)
+{
+ struct device_node *np, *cpu_np;
+ unsigned int cpu;
+ int ret;
+
+ for_each_possible_cpu(cpu) {
+ cpu_np = of_cpu_device_node_get(cpu);
+ if (!cpu_np) {
+ dev_err(&pdev->dev, "Failed to get cpu %d device\n",
+ cpu);
+ continue;
+ }
+
+ np = of_parse_phandle(cpu_np, "qcom,freq-domain", 0);
+ if (!np) {
+ dev_err(&pdev->dev, "Failed to get freq-domain device\n");
+ return -EINVAL;
+ }
+
+ of_node_put(cpu_np);
+
+ ret = qcom_cpu_resources_init(pdev, np, cpu);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+static int qcom_cpufreq_hw_driver_probe(struct platform_device *pdev)
+{
+ int rc;
+
+ /* Get the bases of cpufreq for domains */
+ rc = qcom_resources_init(pdev);
+ if (rc) {
+ dev_err(&pdev->dev, "CPUFreq resource init failed\n");
+ return rc;
+ }
+
+ rc = cpufreq_register_driver(&cpufreq_qcom_hw_driver);
+ if (rc) {
+ dev_err(&pdev->dev, "CPUFreq HW driver failed to register\n");
+ return rc;
+ }
+
+ dev_info(&pdev->dev, "QCOM CPUFreq HW driver initialized\n");
+
+ return 0;
+}
+
+static const struct of_device_id match_table[] = {
+ { .compatible = "qcom,cpufreq-hw", .data = &cpufreq_qcom_std_offsets },
+ {}
+};
+
+static struct platform_driver qcom_cpufreq_hw_driver = {
+ .probe = qcom_cpufreq_hw_driver_probe,
+ .driver = {
+ .name = "qcom-cpufreq-hw",
+ .of_match_table = match_table,
+ .owner = THIS_MODULE,
+ },
+};
+
+static int __init qcom_cpufreq_hw_init(void)
+{
+ return platform_driver_register(&qcom_cpufreq_hw_driver);
+}
+subsys_initcall(qcom_cpufreq_hw_init);
+
+MODULE_DESCRIPTION("QCOM firmware-based CPU Frequency driver");
+MODULE_LICENSE("GPL v2");
--
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