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Message-ID: <1599563425.2621.5.camel@mtkswgap22>
Date: Tue, 8 Sep 2020 19:10:25 +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>, <linux-kernel@...r.kernel.org>,
<wsd_upstream@...iatek.com>
Subject: Re: [PATCH v4 1/2] cpufreq: mediatek-hw: Add support for Mediatek
cpufreq HW driver
On Tue, 2020-09-08 at 15:57 +0530, Viresh Kumar wrote:
> On 08-09-20, 15:35, Hector Yuan wrote:
> > From: "Hector.Yuan" <hector.yuan@...iatek.com>
> >
> > Add MT6779 cpufreq HW support.
> >
> > Signed-off-by: Hector.Yuan <hector.yuan@...iatek.com>
> > ---
> > drivers/cpufreq/Kconfig.arm | 12 ++
> > drivers/cpufreq/Makefile | 1 +
> > drivers/cpufreq/mediatek-cpufreq-hw.c | 294 +++++++++++++++++++++++++++++++++
> > 3 files changed, 307 insertions(+)
> > create mode 100644 drivers/cpufreq/mediatek-cpufreq-hw.c
> >
> > diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
> > index c6cbfc8..8e58c12 100644
> > --- a/drivers/cpufreq/Kconfig.arm
> > +++ b/drivers/cpufreq/Kconfig.arm
> > @@ -121,6 +121,18 @@ 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 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..61040b8
> > --- /dev/null
> > +++ b/drivers/cpufreq/mediatek-cpufreq-hw.c
> > @@ -0,0 +1,294 @@
> > +// 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/slab.h>
> > +
> > +#define LUT_MAX_ENTRIES 32U
> > +#define LUT_FREQ GENMASK(11, 0)
> > +#define LUT_ROW_SIZE 0x4
> > +
> > +enum {
> > + REG_LUT_TABLE,
> > + REG_ENABLE,
> > + REG_PERF_STATE,
> > +
> > + REG_ARRAY_SIZE,
> > +};
> > +
> > +struct cpufreq_mtk {
> > + struct cpufreq_frequency_table *table;
> > + void __iomem *reg_bases[REG_ARRAY_SIZE];
> > + cpumask_t related_cpus;
> > +};
> > +
> > +static const u16 cpufreq_mtk_offsets[REG_ARRAY_SIZE] = {
> > + [REG_LUT_TABLE] = 0x0,
> > + [REG_ENABLE] = 0x84,
> > + [REG_PERF_STATE] = 0x88,
> > +};
> > +
> > +static struct cpufreq_mtk *mtk_freq_domain_map[NR_CPUS];
> > +
> > +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_PERF_STATE]);
> > + arch_set_freq_scale(policy->related_cpus,
> > + policy->freq_table[index].frequency,
> > + policy->cpuinfo.max_freq);
> > +
> > + return 0;
> > +}
> > +
> > +static unsigned int mtk_cpufreq_hw_get(unsigned int cpu)
> > +{
> > + struct cpufreq_mtk *c;
> > + struct cpufreq_policy *policy;
> > + unsigned int index;
> > +
> > + policy = cpufreq_cpu_get_raw(cpu);
> > + if (!policy)
> > + return 0;
> > +
> > + c = policy->driver_data;
> > +
> > + index = readl_relaxed(c->reg_bases[REG_PERF_STATE]);
> > + index = min(index, LUT_MAX_ENTRIES - 1);
> > +
> > + return policy->freq_table[index].frequency;
> > +}
> > +
> > +static int mtk_cpufreq_hw_cpu_init(struct cpufreq_policy *policy)
> > +{
> > + struct cpufreq_mtk *c;
> > + struct device *cpu_dev;
> > +
> > + 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;
> > + }
> > +
> > + 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;
> > +
> > + /* HW should be in enabled state to proceed now */
> > + writel_relaxed(0x1, c->reg_bases[REG_ENABLE]);
> > +
> > + 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,
> > + .name = "mtk-cpufreq-hw",
> > + .attr = mtk_cpufreq_hw_attr,
>
> You can use cpufreq_generic_attr instead.
>
OK, will replace it with cpufreq_generic_attr.
> > +};
> > +
> > +static int mtk_cpufreq_hw_opp_create(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_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;
> > +
> > + return 0;
> > +}
> > +
> > +static int 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);
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int mtk_cpu_resources_init(struct platform_device *pdev,
> > + unsigned int cpu, int index)
> > +{
> > + struct cpufreq_mtk *c;
> > + struct resource *res;
> > + struct device *dev = &pdev->dev;
> > + const u16 *offsets;
> > + int ret, i, cpu_r;
> > + void __iomem *base;
> > +
> > + if (mtk_freq_domain_map[cpu])
> > + return 0;
> > +
> > + c = devm_kzalloc(dev, sizeof(*c), GFP_KERNEL);
> > + if (!c)
> > + return -ENOMEM;
> > +
> > + offsets = of_device_get_match_data(&pdev->dev);
> > + if (!offsets)
> > + return -EINVAL;
>
> Just do this once in probe and pass it to this routine. You don't need
> to do this again and again.
>
OK, I will do it in probe, and pass offsets to this routine.
> > +
> > + res = platform_get_resource(pdev, IORESOURCE_MEM, index);
> > + base = devm_ioremap_resource(dev, res);
> > + if (IS_ERR(base))
> > + return PTR_ERR(base);
> > +
> > + for (i = REG_LUT_TABLE; i < REG_ARRAY_SIZE; i++)
> > + c->reg_bases[i] = base + offsets[i];
> > +
> > + ret = mtk_get_related_cpus(index, &c->related_cpus);
> > + if (ret) {
> > + dev_err(dev, "Domain-%d failed to get related CPUs\n", index);
> > + return ret;
> > + }
> > +
> > + ret = mtk_cpufreq_hw_opp_create(pdev, c);
>
> This isn't creating an OPP table anymore but just a frequency table.
> Name it mtk_cpu_create_freq_table() rather.
>
OK, I will rename this function.
> > + if (ret) {
> > + dev_err(dev, "Domain-%d failed to create OPP\n", index);
> > + return ret;
> > + }
> > +
> > + for_each_cpu(cpu_r, &c->related_cpus)
> > + mtk_freq_domain_map[cpu_r] = c;
> > +
> > + return 0;
> > +}
> > +
> > +static int mtk_resources_init(struct platform_device *pdev)
> > +{
> > + struct device_node *cpu_np;
> > + struct of_phandle_args args;
> > + unsigned int cpu;
> > + int ret;
> > +
> > + for_each_possible_cpu(cpu) {
> > + cpu_np = of_cpu_device_node_get(cpu);
> > + if (!cpu_np) {
> > + dev_dbg(&pdev->dev, "Failed to get cpu %d device\n",
> > + cpu);
> > + continue;
> > + }
> > +
> > + ret = of_parse_phandle_with_args(cpu_np, "mtk-freq-domain",
> > + "#freq-domain-cells", 0, &args);
> > + if (ret < 0)
> > + return ret;
> > +
> > + ret = mtk_cpu_resources_init(pdev, cpu, args.args[0]);
> > + if (ret)
> > + return ret;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int mtk_cpufreq_hw_driver_probe(struct platform_device *pdev)
> > +{
> > + int ret;
> > +
> > + /* Get the bases of cpufreq for domains */
> > + ret = mtk_resources_init(pdev);
>
> Just open-code this here. No need of a separate routine really, there
> is not much there.
>
OK, I will make it as open-code.
> > + 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;
> > + }
> > +
> > + dev_dbg(&pdev->dev, "Mediatek CPUFreq HW driver initialized\n");
>
> Just drop this, this isn't really required. The cpufreq core also
> print some messages for this.
>
OK.
> > + of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev);
>
> Why do you need to do this ? This should happen automatically.
>
OK, will remove this.
> > +
> > + return 0;
> > +}
> > +
> > +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,
> > + .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);
> > +}
> > +subsys_initcall(mtk_cpufreq_hw_init);
>
> subsys_init ? Why this ?
>
OK, I will make it module init.
> You made your driver as a "tristate" driver, and you don't have any
> exit/remove level stuff ?
>
OK, I will define the corresponding exit function.
> > +
> > +MODULE_DESCRIPTION("mtk CPUFREQ HW Driver");
> > +MODULE_LICENSE("GPL v2");
> > --
> > 1.7.9.5
>
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