[PATCH v8 1/3] cpufreq: mediatek-hw: Add support for CPUFREQ HW

Hector Yuan
2020-10-26T08:19:49Z

From: "Hector.Yuan" <hector.yuan@mediatek.com>

Add cpufreq HW support.

Signed-off-by: Hector.Yuan <hector.yuan@mediatek.com>
---
drivers/cpufreq/Kconfig.arm | 12 ++
drivers/cpufreq/Makefile | 1 +
drivers/cpufreq/mediatek-cpufreq-hw.c | 343 +++++++++++++++++++++++++++++++++
3 files changed, 356 insertions(+)
create mode 100644 drivers/cpufreq/mediatek-cpufreq-hw.c

diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
index cb72fb5..b9d17c5 100644
--- a/drivers/cpufreq/Kconfig.arm
+++ b/drivers/cpufreq/Kconfig.arm
@@ -123,6 +123,18 @@ config ARM_MEDIATEK_CPUFREQ
help
This adds the CPUFreq driver support for MediaTek SoCs.

+config ARM_MEDIATEK_CPUFREQ_HW
+ tristate "MediaTek CPUFreq HW driver"
+ depends on ARCH_MEDIATEK || COMPILE_TEST
+ default m
+ help
+ Support for the CPUFreq HW driver.
+ Some MediaTek 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 interface to the OS.
+ The driver implements the cpufreq interface for this HW engine.
+ Say Y if you want to support CPUFreq HW.
+
config ARM_OMAP2PLUS_CPUFREQ
bool "TI OMAP2+"
depends on ARCH_OMAP2PLUS
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index f1b7e3d..ffc61cd 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -57,6 +57,7 @@ obj-$(CONFIG_ARM_IMX6Q_CPUFREQ) += imx6q-cpufreq.o
obj-$(CONFIG_ARM_IMX_CPUFREQ_DT) += imx-cpufreq-dt.o
obj-$(CONFIG_ARM_KIRKWOOD_CPUFREQ) += kirkwood-cpufreq.o
obj-$(CONFIG_ARM_MEDIATEK_CPUFREQ) += mediatek-cpufreq.o
+obj-$(CONFIG_ARM_MEDIATEK_CPUFREQ_HW) += mediatek-cpufreq-hw.o
obj-$(CONFIG_MACH_MVEBU_V7) += mvebu-cpufreq.o
obj-$(CONFIG_ARM_OMAP2PLUS_CPUFREQ) += omap-cpufreq.o
obj-$(CONFIG_ARM_PXA2xx_CPUFREQ) += pxa2xx-cpufreq.o
diff --git a/drivers/cpufreq/mediatek-cpufreq-hw.c b/drivers/cpufreq/mediatek-cpufreq-hw.c
new file mode 100644
index 0000000..3af36b0
--- /dev/null
+++ b/drivers/cpufreq/mediatek-cpufreq-hw.c
@@ -0,0 +1,343 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2020 MediaTek Inc.
+ */
+
+#include <linux/bitfield.h>
+#include <linux/cpufreq.h>
+#include <linux/energy_model.h>
+#include <linux/init.h>
+#include <linux/iopoll.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/pm_qos.h>
+#include <linux/slab.h>
+
+#define LUT_MAX_ENTRIES 32U
+#define LUT_FREQ GENMASK(11, 0)
+#define LUT_ROW_SIZE 0x4
+#define CPUFREQ_HW_STATUS BIT(0)
+#define SVS_HW_STATUS BIT(1)
+#define POLL_USEC 1000
+#define TIMEOUT_USEC 300000
+
+enum {
+ REG_FREQ_LUT_TABLE,
+ REG_FREQ_ENABLE,
+ REG_FREQ_PERF_STATE,
+ REG_FREQ_HW_STATE,
+ REG_EM_POWER_TBL,
+
+ REG_ARRAY_SIZE,
+};
+
+struct cpufreq_mtk {
+ struct cpufreq_frequency_table *table;
+ void __iomem *reg_bases[REG_ARRAY_SIZE];
+ int nr_opp;
+ cpumask_t related_cpus;
+};
+
+static const u16 cpufreq_mtk_offsets[REG_ARRAY_SIZE] = {
+ [REG_FREQ_LUT_TABLE] = 0x0,
+ [REG_FREQ_ENABLE] = 0x84,
+ [REG_FREQ_PERF_STATE] = 0x88,
+ [REG_FREQ_HW_STATE] = 0x8c,
+ [REG_EM_POWER_TBL] = 0x3D0,
+};
+
+static struct cpufreq_mtk *mtk_freq_domain_map[NR_CPUS];
+
+static int mtk_cpufreq_get_cpu_power(unsigned long *mW,
+ unsigned long *KHz, struct device *cpu_dev)
+{
+ struct cpufreq_mtk *c = mtk_freq_domain_map[cpu_dev->id];
+ int i;
+
+ for (i = 0; i < c->nr_opp; i++) {
+ if (c->table[i].frequency < *KHz)
+ break;
+ }
+ i--;
+
+ *KHz = c->table[i].frequency;
+ *mW = readl_relaxed(c->reg_bases[REG_EM_POWER_TBL] +
+ i * LUT_ROW_SIZE) / 1000;
+
+ return 0;
+}
+
+static int mtk_cpufreq_hw_target_index(struct cpufreq_policy *policy,
+ unsigned int index)
+{
+ struct cpufreq_mtk *c = policy->driver_data;
+
+ writel_relaxed(index, c->reg_bases[REG_FREQ_PERF_STATE]);
+
+ return 0;
+}
+
+static unsigned int mtk_cpufreq_hw_get(unsigned int cpu)
+{
+ struct cpufreq_mtk *c;
+ unsigned int index;
+
+ c = mtk_freq_domain_map[cpu];
+
+ index = readl_relaxed(c->reg_bases[REG_FREQ_PERF_STATE]);
+ index = min(index, LUT_MAX_ENTRIES - 1);
+
+ return c->table[index].frequency;
+}
+
+static int mtk_cpufreq_hw_cpu_init(struct cpufreq_policy *policy)
+{
+ struct cpufreq_mtk *c;
+ struct device *cpu_dev;
+ struct em_data_callback em_cb = EM_DATA_CB(mtk_cpufreq_get_cpu_power);
+ struct pm_qos_request *qos_request;
+ int sig, pwr_hw = CPUFREQ_HW_STATUS | SVS_HW_STATUS;
+
+ qos_request = kzalloc(sizeof(*qos_request), GFP_KERNEL);
+ if (!qos_request)
+ return -ENOMEM;
+
+ cpu_dev = get_cpu_device(policy->cpu);
+ if (!cpu_dev) {
+ pr_err("failed to get cpu%d device\n", policy->cpu);
+ return -ENODEV;
+ }
+
+ c = mtk_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->freq_table = c->table;
+ policy->driver_data = c;
+
+ /* Let CPUs leave idle-off state for SVS CPU initializing */
+ cpu_latency_qos_add_request(qos_request, 0);
+
+ /* HW should be in enabled state to proceed now */
+ writel_relaxed(0x1, c->reg_bases[REG_FREQ_ENABLE]);
+
+ if (readl_poll_timeout(c->reg_bases[REG_FREQ_HW_STATE], sig,
+ (sig & pwr_hw) == pwr_hw, POLL_USEC,
+ TIMEOUT_USEC)) {
+ if (!(sig & CPUFREQ_HW_STATUS)) {
+ pr_info("cpufreq hardware of CPU%d is not enabled\n",
+ policy->cpu);
+ return -ENODEV;
+ }
+
+ pr_info("SVS of CPU%d is not enabled\n", policy->cpu);
+ }
+
+ em_dev_register_perf_domain(cpu_dev, c->nr_opp, &em_cb, policy->cpus);
+
+ cpu_latency_qos_remove_request(qos_request);
+ kfree(qos_request);
+
+ return 0;
+}
+
+static int mtk_cpufreq_hw_cpu_exit(struct cpufreq_policy *policy)
+{
+ struct cpufreq_mtk *c;
+
+ c = mtk_freq_domain_map[policy->cpu];
+ if (!c) {
+ pr_err("No scaling support for CPU%d\n", policy->cpu);
+ return -ENODEV;
+ }
+
+ /* HW should be in paused state now */
+ writel_relaxed(0x0, c->reg_bases[REG_FREQ_ENABLE]);
+
+ return 0;
+}
+
+static struct cpufreq_driver cpufreq_mtk_hw_driver = {
+ .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK |
+ CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
+ CPUFREQ_IS_COOLING_DEV,
+ .verify = cpufreq_generic_frequency_table_verify,
+ .target_index = mtk_cpufreq_hw_target_index,
+ .get = mtk_cpufreq_hw_get,
+ .init = mtk_cpufreq_hw_cpu_init,
+ .exit = mtk_cpufreq_hw_cpu_exit,
+ .name = "mtk-cpufreq-hw",
+ .attr = cpufreq_generic_attr,
+};
+
+static int mtk_cpu_create_freq_table(struct platform_device *pdev,
+ struct cpufreq_mtk *c)
+{
+ struct device *dev = &pdev->dev;
+ void __iomem *base_table;
+ u32 data, i, freq, prev_freq = 0;
+
+ c->table = devm_kcalloc(dev, LUT_MAX_ENTRIES + 1,
+ sizeof(*c->table), GFP_KERNEL);
+ if (!c->table)
+ return -ENOMEM;
+
+ base_table = c->reg_bases[REG_FREQ_LUT_TABLE];
+
+ for (i = 0; i < LUT_MAX_ENTRIES; i++) {
+ data = readl_relaxed(base_table + (i * LUT_ROW_SIZE));
+ freq = FIELD_GET(LUT_FREQ, data) * 1000;
+
+ if (freq == prev_freq)
+ break;
+
+ c->table[i].frequency = freq;
+
+ dev_dbg(dev, "index=%d freq=%d\n",
+ i, c->table[i].frequency);
+
+ prev_freq = freq;
+ }
+
+ c->table[i].frequency = CPUFREQ_TABLE_END;
+ c->nr_opp = i;
+
+ return 0;
+}
+
+static int mtk_get_related_cpus(int index, struct cpufreq_mtk *c)
+{
+ struct device_node *cpu_np;
+ struct of_phandle_args args;
+ int cpu, ret;
+
+ for_each_possible_cpu(cpu) {
+ cpu_np = of_cpu_device_node_get(cpu);
+ if (!cpu_np)
+ continue;
+
+ ret = of_parse_phandle_with_args(cpu_np, "mediatek,freq-domain",
+ "#freq-domain-cells", 0,
+ &args);
+ of_node_put(cpu_np);
+ if (ret < 0)
+ continue;
+
+ if (index == args.args[0]) {
+ cpumask_set_cpu(cpu, &c->related_cpus);
+ mtk_freq_domain_map[cpu] = c;
+ }
+ }
+
+ return 0;
+}
+
+static int mtk_cpu_resources_init(struct platform_device *pdev,
+ unsigned int cpu, int index,
+ const u16 *offsets)
+{
+ struct cpufreq_mtk *c;
+ struct device *dev = &pdev->dev;
+ int ret, i;
+ void __iomem *base;
+
+ if (mtk_freq_domain_map[cpu])
+ return 0;
+
+ c = devm_kzalloc(dev, sizeof(*c), GFP_KERNEL);
+ if (!c)
+ return -ENOMEM;
+
+ base = devm_platform_ioremap_resource(pdev, index);
+ if (IS_ERR(base))
+ return PTR_ERR(base);
+
+ for (i = REG_FREQ_LUT_TABLE; i < REG_ARRAY_SIZE; i++)
+ c->reg_bases[i] = base + offsets[i];
+
+ ret = mtk_get_related_cpus(index, c);
+ if (ret) {
+ dev_err(dev, "Domain-%d failed to get related CPUs\n", index);
+ return ret;
+ }
+
+ ret = mtk_cpu_create_freq_table(pdev, c);
+ if (ret) {
+ dev_err(dev, "Domain-%d failed to create freq table\n", index);
+ return ret;
+ }
+
+ return 0;
+}
+
+static int mtk_cpufreq_hw_driver_probe(struct platform_device *pdev)
+{
+ struct device_node *cpu_np;
+ struct of_phandle_args args;
+ const u16 *offsets;
+ unsigned int cpu;
+ int ret;
+
+ offsets = of_device_get_match_data(&pdev->dev);
+ if (!offsets)
+ return -EINVAL;
+
+ 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);
+ return -ENODEV;
+ }
+
+ ret = of_parse_phandle_with_args(cpu_np, "mediatek,freq-domain",
+ "#freq-domain-cells", 0,
+ &args);
+ if (ret < 0)
+ return ret;
+
+ /* Get the bases of cpufreq for domains */
+ ret = mtk_cpu_resources_init(pdev, cpu, args.args[0], offsets);
+ if (ret) {
+ dev_err(&pdev->dev, "CPUFreq resource init failed\n");
+ return ret;
+ }
+ }
+
+ ret = cpufreq_register_driver(&cpufreq_mtk_hw_driver);
+ if (ret) {
+ dev_err(&pdev->dev, "CPUFreq HW driver failed to register\n");
+ return ret;
+ }
+
+ return 0;
+}
+
+static int mtk_cpufreq_hw_driver_remove(struct platform_device *pdev)
+{
+ return cpufreq_unregister_driver(&cpufreq_mtk_hw_driver);
+}
+
+static const struct of_device_id mtk_cpufreq_hw_match[] = {
+ { .compatible = "mediatek,cpufreq-hw", .data = &cpufreq_mtk_offsets },
+ {}
+};
+
+static struct platform_driver mtk_cpufreq_hw_driver = {
+ .probe = mtk_cpufreq_hw_driver_probe,
+ .remove = mtk_cpufreq_hw_driver_remove,
+ .driver = {
+ .name = "mtk-cpufreq-hw",
+ .of_match_table = mtk_cpufreq_hw_match,
+ },
+};
+module_platform_driver(mtk_cpufreq_hw_driver);
+
+MODULE_DESCRIPTION("Mediatek cpufreq-hw driver");
+MODULE_LICENSE("GPL v2");
--
1.7.9.5