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    SubjectRe: [PATCH v13 2/2] cpufreq: mediatek-hw: Add support for CPUFREQ HW
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    On Tue, 2021-08-03 at 12:43 +0530, Viresh Kumar wrote:
    > On 30-07-21, 00:08, Hector Yuan wrote:
    > > From: "Hector.Yuan" <hector.yuan@mediatek.com>
    > >
    > > Add cpufreq HW support
    >
    > Please write a proper commit log, what you are adding and which SoCs
    > it will apply to. Also add a full stop (.) at the end.
    >
    OK, I will write down more details
    > > Signed-off-by: Hector.Yuan <hector.yuan@mediatek.com>
    > > ---
    > > drivers/cpufreq/Kconfig.arm | 12 ++
    > > drivers/cpufreq/Makefile | 1 +
    > > drivers/cpufreq/mediatek-cpufreq-hw.c | 357 +++++++++++++++++++++++++++++++++
    > > include/linux/cpufreq.h | 39 ++++
    >
    > The changes to cpufreq.h should be done in a separate patch.
    >
    OK, will separate .h to another patch
    > > diff --git a/drivers/cpufreq/mediatek-cpufreq-hw.c b/drivers/cpufreq/mediatek-cpufreq-hw.c
    > > new file mode 100644
    > > index 0000000..ca50a3a
    > > --- /dev/null
    > > +++ b/drivers/cpufreq/mediatek-cpufreq-hw.c
    > > @@ -0,0 +1,357 @@
    > > +// 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_FREQ_LATENCY,
    > > +
    > > + 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] = 0x90,
    > > + [REG_FREQ_LATENCY] = 0x110,
    > > +};
    > > +
    > > +static struct cpufreq_mtk *mtk_freq_domain_map[NR_CPUS];
    > > +
    > > +static int __maybe_unused
    > > +mtk_cpufreq_get_cpu_power(unsigned long *mW,
    > > + unsigned long *KHz, struct device *cpu_dev)
    > > +{
    > > + struct cpufreq_mtk *c;
    > > + struct cpufreq_policy *policy;
    > > + int i;
    > > +
    > > + policy = cpufreq_cpu_get_raw(cpu_dev->id);
    > > + if (!policy)
    > > + return 0;
    > > +
    > > + c = mtk_freq_domain_map[policy->cpu];
    > > +
    > > + 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;
    > > + struct cpufreq_policy *policy;
    > > + unsigned int index;
    > > +
    > > + policy = cpufreq_cpu_get_raw(cpu);
    > > + if (!policy)
    > > + return 0;
    > > +
    > > + c = mtk_freq_domain_map[policy->cpu];
    > > +
    > > + index = readl_relaxed(c->reg_bases[REG_FREQ_PERF_STATE]);
    > > + index = min(index, LUT_MAX_ENTRIES - 1);
    > > +
    > > + return c->table[index].frequency;
    > > +}
    > > +
    > > +static unsigned int mtk_cpufreq_hw_fast_switch(struct cpufreq_policy *policy,
    > > + unsigned int target_freq)
    > > +{
    > > + struct cpufreq_mtk *c = policy->driver_data;
    > > + unsigned int index;
    > > +
    > > + index = cpufreq_table_find_index_dl(policy, target_freq);
    > > +
    > > + writel_relaxed(index, c->reg_bases[REG_FREQ_PERF_STATE]);
    > > +
    > > + return policy->freq_table[index].frequency;
    > > +}
    > > +
    > > +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);
    >
    > Won't this fit in a single line ?
    >
    OK, will modify to single line
    > > +
    > > + prev_freq = freq;
    > > + }
    > > +
    > > + c->table[i].frequency = CPUFREQ_TABLE_END;
    > > + c->nr_opp = i;
    > > +
    > > + 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])
    >
    > This should not happen anymore, isn't it ?
    >
    Will remove cpu map.
    > > + 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 = of_perf_domain_get_sharing_cpumask(index, "performance-domains",
    >
    > Instead of parsing parsing "performance-domains" twice, I would rather
    > pass a CPU number here instead of index.
    >
    Sorry, could you give me more details? For now, will use index to parse
    per-cpu to related cpus.You mean pass policy->cpu or? Thanks.
    > > + "#performance-domain-cells",
    > > + &c->related_cpus);
    >
    > You could have directly passed policy->cpus here instead.
    >
    will replace it.
    > > + if (ret) {
    > > + dev_info(dev, "Domain-%d failed to get related CPUs\n", index);
    > > + return ret;
    > > + }
    > > +
    > > + ret = mtk_cpu_create_freq_table(pdev, c);
    > > + if (ret) {
    > > + dev_info(dev, "Domain-%d failed to create freq table\n", index);
    > > + return ret;
    > > + }
    > > +
    > > + mtk_freq_domain_map[cpu] = c;
    >
    > I will rather use policy->driver_data to store this now.
    >
    OK
    > > +
    > > + return 0;
    > > +}
    > > +
    > > +static int mtk_cpufreq_hw_cpu_init(struct cpufreq_policy *policy)
    > > +{
    > > + struct platform_device *pdev = cpufreq_get_driver_data();
    > > + 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;
    > > + struct device_node *cpu_np;
    > > + struct of_phandle_args args;
    > > + const u16 *offsets;
    > > + unsigned int latency;
    > > + int sig, pwr_hw = CPUFREQ_HW_STATUS | SVS_HW_STATUS;
    > > + int ret;
    >
    > It looks much more organized when the variable definitions are in
    > decreasing order of their length, instead of the random order as it is
    > right now.
    >
    OK, will sort it.
    > > +
    > > + offsets = of_device_get_match_data(&pdev->dev);
    > > + if (!offsets)
    > > + return -EINVAL;
    > > +
    > > + cpu_np = of_cpu_device_node_get(policy->cpu);
    > > + if (!cpu_np) {
    > > + dev_info(&pdev->dev, "Failed to get cpu %d device\n",
    > > + policy->cpu);
    > > + return -ENODEV;
    > > + }
    > > +
    > > + ret = of_parse_phandle_with_args(cpu_np, "performance-domains",
    > > + "#performance-domain-cells", 0,
    > > + &args);
    > > + if (ret < 0)
    >
    > What about dropping cpu_np and same later in the code as well ?
    >
    OK, Will add it.
    > > + return ret;
    > > +
    > > + /* Get the bases of cpufreq for domains */
    > > + ret = mtk_cpu_resources_init(pdev, policy->cpu, args.args[0], offsets);
    > > + if (ret) {
    > > + dev_info(&pdev->dev, "CPUFreq resource init failed\n");
    > > + return ret;
    > > + }
    > > +
    > > + 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;
    >
    > Oh you already do this, you can remove mtk_freq_domain_map array now.
    >
    OK, will remove map.
    > > +
    > > + latency = readl_relaxed(c->reg_bases[REG_FREQ_LATENCY]);
    > > + if (!latency)
    > > + latency = CPUFREQ_ETERNAL;
    > > +
    > > + /* us convert to ns */
    > > + policy->cpuinfo.transition_latency = latency * 1000;
    >
    > You want to multiple CPUFREQ_ETERNAL too ?
    >
    Yes, may be different power domain with different transition latency.
    > > +
    > > + policy->fast_switch_possible = true;
    > > +
    > > + qos_request = kzalloc(sizeof(*qos_request), GFP_KERNEL);
    >
    > This is a small structure, why not allocate it on stack instead ?
    >
    For qos part, we'd like to take more time to re-consider the SW flow and
    put this to another patch set.Is this okay to you?
    > > + if (!qos_request)
    > > + return -ENOMEM;
    > > +
    > > + /* 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);
    > > + }
    > > +
    > > + cpu_latency_qos_remove_request(qos_request);
    > > +
    > > + em_dev_register_perf_domain(cpu_dev, c->nr_opp, &em_cb, policy->cpus, true);
    > > +
    > > + kfree(qos_request);
    >
    > Why free after registering for em ? And also move the entire qos thing
    > into a separate routine instead of adding it to ->init().
    >
    If you agree, we'll consider to put it in another patch set.
    > > +
    > > + return 0;
    > > +}
    > > +
    > > +static int mtk_cpufreq_hw_cpu_exit(struct cpufreq_policy *policy)
    > > +{
    > > + struct cpufreq_mtk *c;
    > > +
    > > + c = mtk_freq_domain_map[policy->cpu];
    > > +
    > > + /* HW should be in paused state now */
    > > + writel_relaxed(0x0, c->reg_bases[REG_FREQ_ENABLE]);
    >
    > Please make sure each and every resource is freed here and in probe on
    > failures.
    >
    OK, will free all resources as probe.
    > > +
    > > + return 0;
    > > +}
    > > +
    > > +static struct cpufreq_driver cpufreq_mtk_hw_driver = {
    > > + .flags = 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,
    > > + .fast_switch = mtk_cpufreq_hw_fast_switch,
    > > + .name = "mtk-cpufreq-hw",
    > > + .attr = cpufreq_generic_attr,
    > > +};
    > > +
    > > +static int mtk_cpufreq_hw_driver_probe(struct platform_device *pdev)
    > > +{
    > > + int ret;
    > > +
    > > + cpufreq_mtk_hw_driver.driver_data = pdev;
    > > +
    > > + 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;
    >
    > You can do return ret here and drop the earlier return and its {}.
    >
    okay.
    > > +}
    > > +
    > > +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");
    >
    > You can add Module-author as well here if you want.
    >
    OK.
    > > diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
    > > index 9fd7194..4916d70 100644
    > > --- a/include/linux/cpufreq.h
    > > +++ b/include/linux/cpufreq.h
    > > @@ -13,6 +13,8 @@
    > > #include <linux/completion.h>
    > > #include <linux/kobject.h>
    > > #include <linux/notifier.h>
    > > +#include <linux/of.h>
    > > +#include <linux/of_device.h>
    > > #include <linux/pm_qos.h>
    > > #include <linux/spinlock.h>
    > > #include <linux/sysfs.h>
    > > @@ -1036,6 +1038,43 @@ void arch_set_freq_scale(const struct cpumask *cpus,
    > > }
    > > #endif
    > >
    > > +#ifdef CONFIG_CPU_FREQ
    >
    > There is another CONFIG_CPU_FREQ a few lines above, please use the
    > same block for this routine as well.
    >
    OK, will move it to the above.
    > > +static inline int of_perf_domain_get_sharing_cpumask(int index, const char *list_name,
    > > + const char *cell_name,
    > > + struct cpumask *cpumask)
    > > +{
    > > + 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, list_name,
    > > + cell_name, 0,
    > > + &args);
    > > +
    > > + of_node_put(cpu_np);
    > > + if (ret < 0)
    > > + continue;
    > > +
    > > + if (index == args.args[0])
    > > + cpumask_set_cpu(cpu, cpumask);
    > > + }
    > > +
    > > + return 0;
    > > +}
    > > +#else
    > > +static inline int of_perf_domain_get_sharing_cpumask(int index, const char *list_name,
    > > + const char *cell_name,
    > > + struct cpumask *cpumask)
    > > +{
    > > + return 0;
    >
    > return -EOPNOTSUPP;
    >
    > > +}
    > > +#endif
    >

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