[PATCH v1 1/2] cpufreq: mediatek-hw: Add support for Mediatek cpufreq HW driver

Hector Yuan
2020-08-06T16:30:55Z

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

Add MT6779 cpufreq HW support.

Signed-off-by: Hector.Yuan <hector.yuan@mediatek.com>
---
arch/arm64/configs/defconfig | 1 +
drivers/cpufreq/Kconfig.arm | 11 ++
drivers/cpufreq/Makefile | 1 +
drivers/cpufreq/mediatek-cpufreq-hw.c | 255 +++++++++++++++++++++++++++++++++
4 files changed, 268 insertions(+)
create mode 100644 drivers/cpufreq/mediatek-cpufreq-hw.c

diff --git a/arch/arm64/configs/defconfig b/arch/arm64/configs/defconfig
index 883e8ba..866a1bf 100644
--- a/arch/arm64/configs/defconfig
+++ b/arch/arm64/configs/defconfig
@@ -86,6 +86,7 @@ CONFIG_CPUFREQ_DT=y
CONFIG_ACPI_CPPC_CPUFREQ=m
CONFIG_ARM_ALLWINNER_SUN50I_CPUFREQ_NVMEM=m
CONFIG_ARM_ARMADA_37XX_CPUFREQ=y
+CONFIG_ARM_MEDIATEK_CPUFREQ_HW=m
CONFIG_ARM_SCPI_CPUFREQ=y
CONFIG_ARM_IMX_CPUFREQ_DT=m
CONFIG_ARM_QCOM_CPUFREQ_NVMEM=y
diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
index c6cbfc8..81f1cc1 100644
--- a/drivers/cpufreq/Kconfig.arm
+++ b/drivers/cpufreq/Kconfig.arm
@@ -121,6 +121,17 @@ 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
+ 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 f6670c4..dc1f371 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..920cc87
--- /dev/null
+++ b/drivers/cpufreq/mediatek-cpufreq-hw.c
@@ -0,0 +1,255 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2018, The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/bitfield.h>
+#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>
+#include <linux/pm_opp.h>
+#include <linux/slab.h>
+
+#define LUT_MAX_ENTRIES 32U
+#define LUT_FREQ GENMASK(11, 0)
+#define LUT_VOLT GENMASK(28, 12)
+#define LUT_ROW_SIZE 0x4
+
+/* Register offsets */
+#define REG_ENABLE 0x84
+#define REG_PERF_STATE 0x88
+
+static struct platform_device *global_pdev;
+static int mtk_cpufreq_hw_target_index(struct cpufreq_policy *policy,
+ unsigned int index)
+{
+ void __iomem *perf_state_reg = policy->driver_data;
+ unsigned long freq = policy->freq_table[index].frequency;
+
+ writel_relaxed(index, perf_state_reg);
+ arch_set_freq_scale(policy->related_cpus, freq,
+ policy->cpuinfo.max_freq);
+ return 0;
+}
+
+static unsigned int mtk_cpufreq_hw_get(unsigned int cpu)
+{
+ void __iomem *perf_state_reg;
+ struct cpufreq_policy *policy;
+ unsigned int index;
+
+ policy = cpufreq_cpu_get_raw(cpu);
+ if (!policy)
+ return 0;
+
+ perf_state_reg = policy->driver_data;
+
+ index = readl_relaxed(perf_state_reg);
+ index = min(index, LUT_MAX_ENTRIES - 1);
+
+ return policy->freq_table[index].frequency;
+}
+
+static int mtk_cpufreq_hw_read_lut(struct device *cpu_dev,
+ struct cpufreq_policy *policy,
+ void __iomem *base)
+{
+ u32 data;
+ u32 freq, volt, prev_freq = 0;
+ int i = 0;
+ struct cpufreq_frequency_table *table;
+
+ table = kcalloc(LUT_MAX_ENTRIES + 1, sizeof(*table), GFP_KERNEL);
+ if (!table)
+ return -ENOMEM;
+
+ for (i = 0; i < LUT_MAX_ENTRIES; i++) {
+ data = readl_relaxed(base + (i * LUT_ROW_SIZE));
+ freq = FIELD_GET(LUT_FREQ, data) * 1000;
+ volt = FIELD_GET(LUT_VOLT, data);
+ if (freq != prev_freq) {
+ table[i].frequency = freq;
+ dev_pm_opp_add(cpu_dev, freq * 1000, volt);
+ dev_dbg(cpu_dev, "index=%d freq=%d, volt=%d\n", i,
+ freq, volt);
+ } else {
+ break;
+ }
+ prev_freq = freq;
+ }
+ table[i].frequency = CPUFREQ_TABLE_END;
+ policy->freq_table = table;
+ dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
+
+ return 0;
+}
+
+static void mtk_get_related_cpus(int index, struct cpumask *m)
+{
+ 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, "mtk,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, m);
+ }
+}
+
+static int mtk_cpufreq_hw_cpu_init(struct cpufreq_policy *policy)
+{
+ struct device *dev = &global_pdev->dev;
+ struct of_phandle_args args;
+ struct device_node *cpu_np;
+ struct device *cpu_dev;
+ struct resource *res;
+ void __iomem *base;
+ int ret, index;
+
+ cpu_dev = get_cpu_device(policy->cpu);
+ if (!cpu_dev) {
+ pr_err("%s: failed to get cpu%d device\n", __func__,
+ policy->cpu);
+ return -ENODEV;
+ }
+
+ cpu_np = of_cpu_device_node_get(policy->cpu);
+ if (!cpu_np)
+ return -EINVAL;
+
+ ret = of_parse_phandle_with_args(cpu_np, "mtk,freq-domain",
+ "#freq-domain-cells", 0, &args);
+ of_node_put(cpu_np);
+ if (ret)
+ return ret;
+
+ index = args.args[0];
+ res = platform_get_resource(global_pdev, IORESOURCE_MEM, index);
+ if (!res)
+ return -ENODEV;
+ base = devm_ioremap(dev, res->start, resource_size(res));
+ if (!base)
+ return -ENOMEM;
+
+ mtk_get_related_cpus(index, policy->cpus);
+ if (!cpumask_weight(policy->cpus)) {
+ dev_err(dev, "Domain-%d failed to get related CPUs\n", index);
+ ret = -ENOENT;
+ goto error;
+ }
+
+ policy->driver_data = base + REG_PERF_STATE;
+ ret = mtk_cpufreq_hw_read_lut(cpu_dev, policy, base);
+ if (ret) {
+ dev_err(dev, "Domain-%d failed to read LUT\n", index);
+ goto error;
+ }
+
+ ret = dev_pm_opp_get_opp_count(cpu_dev);
+ if (ret <= 0) {
+ dev_err(cpu_dev, "Failed to add OPPs\n");
+ ret = -ENODEV;
+ goto error;
+ }
+
+ dev_pm_opp_of_register_em(policy->cpus);
+
+ /* HW should be in enabled state to proceed now */
+ writel_relaxed(0x1, (base + REG_ENABLE));
+ return 0;
+error:
+ devm_iounmap(dev, base);
+ return ret;
+}
+
+static int mtk_cpufreq_hw_cpu_exit(struct cpufreq_policy *policy)
+{
+ struct device *cpu_dev = get_cpu_device(policy->cpu);
+ void __iomem *base = policy->driver_data - REG_PERF_STATE;
+
+ dev_pm_opp_remove_all_dynamic(cpu_dev);
+ kfree(policy->freq_table);
+ devm_iounmap(&global_pdev->dev, base);
+
+ return 0;
+}
+
+static struct freq_attr *mtk_cpufreq_hw_attr[] = {
+ &cpufreq_freq_attr_scaling_available_freqs,
+ NULL
+};
+
+static struct cpufreq_driver cpufreq_mtk_hw_driver = {
+ .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK |
+ CPUFREQ_HAVE_GOVERNOR_PER_POLICY,
+ .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 = mtk_cpufreq_hw_attr,
+};
+
+static int mtk_cpufreq_hw_driver_probe(struct platform_device *pdev)
+{
+ int ret;
+
+ global_pdev = pdev;
+ ret = cpufreq_register_driver(&cpufreq_mtk_hw_driver);
+ if (ret)
+ dev_err(&pdev->dev, "CPUFreq HW driver failed to register\n");
+ else
+ dev_dbg(&pdev->dev, "mtk CPUFreq HW driver initialized\n");
+
+ return ret;
+}
+
+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" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, mtk_cpufreq_hw_match);
+
+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,
+ },
+};
+
+static int __init mtk_cpufreq_hw_init(void)
+{
+ return platform_driver_register(&mtk_cpufreq_hw_driver);
+}
+postcore_initcall(mtk_cpufreq_hw_init);
+
+static void __exit mtk_cpufreq_hw_exit(void)
+{
+ platform_driver_unregister(&mtk_cpufreq_hw_driver);
+}
+module_exit(mtk_cpufreq_hw_exit);
+
+MODULE_DESCRIPTION("mtk CPUFREQ HW Driver");
+MODULE_LICENSE("GPL v2");
--
1.7.9.5