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Message-ID: <1598446624.24220.10.camel@mtkswgap22>
Date: Wed, 26 Aug 2020 20:57:04 +0800
From: Hector Yuan <hector.yuan@...iatek.com>
To: Viresh Kumar <viresh.kumar@...aro.org>
CC: <linux-mediatek@...ts.infradead.org>,
<linux-arm-kernel@...ts.infradead.org>, <linux-pm@...r.kernel.org>,
<devicetree@...r.kernel.org>,
"Rafael J. Wysocki" <rjw@...ysocki.net>,
"Rob Herring" <robh+dt@...nel.org>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will@...nel.org>,
Matthias Brugger <matthias.bgg@...il.com>,
Bjorn Andersson <bjorn.andersson@...aro.org>,
Shawn Guo <shawnguo@...nel.org>, Li Yang <leoyang.li@....com>,
Vinod Koul <vkoul@...nel.org>, Arnd Bergmann <arnd@...db.de>,
Anson Huang <Anson.Huang@....com>,
Geert Uytterhoeven <geert+renesas@...der.be>,
"Olof Johansson" <olof@...om.net>, <linux-kernel@...r.kernel.org>,
<wsd_upstream@...iatek.com>
Subject: Re: [PATCH v2 1/2] cpufreq: mediatek-hw: Add support for Mediatek
cpufreq HW driver
On Mon, 2020-08-24 at 15:36 +0530, Viresh Kumar wrote:
> On 13-08-20, 15:07, Hector Yuan wrote:
> > From: "Hector.Yuan" <hector.yuan@...iatek.com>
> >
> > Add MT6779 cpufreq HW support.
> >
> > Signed-off-by: Hector.Yuan <hector.yuan@...iatek.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
>
> What about a 'default m' in Kconfig itself ?
> OK, will update in V3.
> > 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..6752db9
> > --- /dev/null
> > +++ b/drivers/cpufreq/mediatek-cpufreq-hw.c
> > @@ -0,0 +1,255 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (c) 2020 MediaTek Inc.
> > + */
> > +
> > +#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;
>
> Use cpufreq_driver->driver_data for this, it is already used in other
> drivers for similar use.
> OK, I see.will update in V3.
> > +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,
>
> This routine needs to be named better, it is creating the cpufreq
> table after all.
> OK, will update in V3. rename to xxx_opp_create.
> > + struct cpufreq_policy *policy,
> > + void __iomem *base)
>
> Please make sure checkpatch --strict doesn't give any errors.
>
> > +{
> > + u32 data;
> > + u32 freq, volt, prev_freq = 0;
>
> Merge these two..
> OK
> > + 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);
>
> Why are you adding OPPs here and rather why using OPP specific stuff
> at all in the driver ?
> yes, the opp information is read from CPU HW engine.Then add it to the CPU dev OPP one by one.
> > + 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",
>
> Where are bindings of this node and how does this look ?
> Can refer to the same patch series, I split it to another patch.Each cpu will be group into one frequency domain for the CPU DVFS.
> > + "#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
>
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