On 17-05-18, 15:00, Taniya Das wrote:
> The CPUfreq FW present in some QCOM chipsets offloads the steps necessary
> for hanging the frequency of CPUs. The driver implements the cpufreq driver
> interface for this firmware.
> 
> Signed-off-by: Taniya Das <t...@codeaurora.org>
> ---
>  drivers/cpufreq/Kconfig.arm       |   9 ++
>  drivers/cpufreq/Makefile          |   1 +
>  drivers/cpufreq/qcom-cpufreq-fw.c | 318 
> ++++++++++++++++++++++++++++++++++++++
>  3 files changed, 328 insertions(+)
>  create mode 100644 drivers/cpufreq/qcom-cpufreq-fw.c
> 
> diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
> index 96b35b8..a50aa6e 100644
> --- a/drivers/cpufreq/Kconfig.arm
> +++ b/drivers/cpufreq/Kconfig.arm
> @@ -301,3 +301,12 @@ config ARM_PXA2xx_CPUFREQ
>         This add the CPUFreq driver support for Intel PXA2xx SOCs.
> 
>         If in doubt, say N.
> +
> +config ARM_QCOM_CPUFREQ_FW
> +     tristate "QCOM CPUFreq FW driver"
> +     help
> +      Support for the CPUFreq FW driver.
> +      The CPUfreq FW preset in some QCOM chipsets offloads the steps
> +      necessary for changing the frequency of CPUs. The driver
> +      implements the cpufreq driver interface for this firmware.
> +      Say Y if you want to support CPUFreq FW.
> diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
> index 8d24ade..a3edbce 100644
> --- a/drivers/cpufreq/Makefile
> +++ b/drivers/cpufreq/Makefile
> @@ -85,6 +85,7 @@ obj-$(CONFIG_ARM_TEGRA124_CPUFREQ)  += tegra124-cpufreq.o
>  obj-$(CONFIG_ARM_TEGRA186_CPUFREQ)   += tegra186-cpufreq.o
>  obj-$(CONFIG_ARM_TI_CPUFREQ)         += ti-cpufreq.o
>  obj-$(CONFIG_ARM_VEXPRESS_SPC_CPUFREQ)       += vexpress-spc-cpufreq.o
> +obj-$(CONFIG_ARM_QCOM_CPUFREQ_FW)    += qcom-cpufreq-fw.o
> 
> 
>  
> ##################################################################################
> diff --git a/drivers/cpufreq/qcom-cpufreq-fw.c 
> b/drivers/cpufreq/qcom-cpufreq-fw.c
> new file mode 100644
> index 0000000..67996d5
> --- /dev/null
> +++ b/drivers/cpufreq/qcom-cpufreq-fw.c
> @@ -0,0 +1,318 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2018, The Linux Foundation. All rights reserved.
> + */
> +
> +#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>
> +
> +#define INIT_RATE                    300000000UL
> +#define XO_RATE                              19200000UL
> +#define LUT_MAX_ENTRIES                      40U
> +#define CORE_COUNT_VAL(val)          ((val & GENMASK(18, 16)) >> 16)
> +#define LUT_ROW_SIZE                 32
> +
> +struct cpufreq_qcom {
> +     struct cpufreq_frequency_table *table;
> +     struct device *dev;
> +     void __iomem *perf_base;
> +     void __iomem *lut_base;
> +     cpumask_t related_cpus;
> +     unsigned int max_cores;
> +};
> +
> +static struct cpufreq_qcom *qcom_freq_domain_map[NR_CPUS];
> +
> +static int
> +qcom_cpufreq_fw_target_index(struct cpufreq_policy *policy, unsigned int 
> index)
> +{
> +     struct cpufreq_qcom *c = policy->driver_data;
> +
> +     if (index >= LUT_MAX_ENTRIES) {
> +             dev_err(c->dev,
> +             "Passing an index (%u) that's greater than max (%d)\n",

Alignment issues here. Run checkpatch --strict.

> +                                     index, LUT_MAX_ENTRIES - 1);
> +             return -EINVAL;
> +     }
> +
> +     writel_relaxed(index, c->perf_base);
> +
> +     /* Make sure the write goes through before proceeding */
> +     mb();
> +     return 0;
> +}
> +
> +static unsigned int qcom_cpufreq_fw_get(unsigned int cpu)
> +{
> +     struct cpufreq_qcom *c;
> +     unsigned int index;
> +
> +     c = qcom_freq_domain_map[cpu];
> +     if (!c)
> +             return -ENODEV;
> +
> +     index = readl_relaxed(c->perf_base);
> +     index = min(index, LUT_MAX_ENTRIES - 1);
> +
> +     return c->table[index].frequency;
> +}
> +
> +static int qcom_cpufreq_fw_cpu_init(struct cpufreq_policy *policy)
> +{
> +     struct cpufreq_qcom *c;
> +     int ret;
> +
> +     c = qcom_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->table = c->table;
> +     policy->driver_data = c;
> +
> +     return ret;
> +}
> +
> +static struct freq_attr *qcom_cpufreq_fw_attr[] = {
> +     &cpufreq_freq_attr_scaling_available_freqs,
> +     &cpufreq_freq_attr_scaling_boost_freqs,
> +     NULL
> +};
> +
> +static struct cpufreq_driver cpufreq_qcom_fw_driver = {
> +     .flags          = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK |
> +                       CPUFREQ_HAVE_GOVERNOR_PER_POLICY,
> +     .verify         = cpufreq_generic_frequency_table_verify,
> +     .target_index   = qcom_cpufreq_fw_target_index,
> +     .get            = qcom_cpufreq_fw_get,
> +     .init           = qcom_cpufreq_fw_cpu_init,
> +     .name           = "qcom-cpufreq-fw",
> +     .attr           = qcom_cpufreq_fw_attr,
> +     .boost_enabled  = true,
> +};
> +
> +static int qcom_read_lut(struct platform_device *pdev,
> +                     struct cpufreq_qcom *c)
> +{
> +     struct device *dev = &pdev->dev;
> +     u32 data, src, lval, i, core_count, prev_cc = 0;
> +
> +     c->table = devm_kcalloc(dev, LUT_MAX_ENTRIES + 1,
> +                             sizeof(*c->table), GFP_KERNEL);
> +     if (!c->table)
> +             return -ENOMEM;
> +
> +     for (i = 0; i < LUT_MAX_ENTRIES; i++) {
> +             data = readl_relaxed(c->lut_base + i * LUT_ROW_SIZE);
> +             src = ((data & GENMASK(31, 30)) >> 30);
> +             lval = (data & GENMASK(7, 0));
> +             core_count = CORE_COUNT_VAL(data);

Why do you need this here ? And why do below in case this doesn't
match max-cores count ?

> +
> +             if (!src)
> +                     c->table[i].frequency = INIT_RATE / 1000;
> +             else
> +                     c->table[i].frequency = XO_RATE * lval / 1000;
> +
> +             c->table[i].driver_data = c->table[i].frequency;
> +
> +             dev_dbg(dev, "index=%d freq=%d, core_count %d\n",
> +                             i, c->table[i].frequency, core_count);
> +
> +             if (core_count != c->max_cores)
> +                     c->table[i].frequency = CPUFREQ_ENTRY_INVALID;
> +
> +             /*
> +              * Two of the same frequencies with the same core counts means
> +              * end of table.
> +              */
> +             if (i > 0 && c->table[i - 1].driver_data ==
> +                                     c->table[i].driver_data
> +                                     && prev_cc == core_count) {
> +                     struct cpufreq_frequency_table *prev = &c->table[i - 1];
> +
> +                     if (prev->frequency == CPUFREQ_ENTRY_INVALID) {
> +                             prev->flags = CPUFREQ_BOOST_FREQ;
> +                             prev->frequency = prev->driver_data;
> +                     }
> +
> +                     break;
> +             }
> +             prev_cc = core_count;
> +     }
> +     c->table[i].frequency = CPUFREQ_TABLE_END;
> +
> +     return 0;
> +}
> +
> +static int qcom_get_related_cpus(struct device_node *np, struct cpumask *m)
> +{
> +     struct device_node *dev_phandle;
> +     struct device *cpu_dev;
> +     int cpu, i = 0, ret = -ENOENT;
> +
> +     dev_phandle = of_parse_phandle(np, "qcom,cpulist", i++);

TBH, I am not a great fan of the CPU phandle list you have created
here. Lets see what Rob has to say on this.

> +     while (dev_phandle) {
> +             for_each_possible_cpu(cpu) {
> +                     cpu_dev = get_cpu_device(cpu);
> +                     if (cpu_dev && cpu_dev->of_node == dev_phandle) {
> +                             cpumask_set_cpu(cpu, m);
> +                             ret = 0;

Maybe just remove this line ...

> +                             break;
> +                     }
> +             }
> +             dev_phandle = of_parse_phandle(np, "qcom,cpulist", i++);
> +     }
> +
> +     return ret;

and check for empty cpumask for an error here.

> +}
> +
> +static int qcom_cpu_resources_init(struct platform_device *pdev,
> +                                             struct device_node *np)

You may want to align these properly. Try running checkpatch with
--strict option.

> +{
> +     struct cpufreq_qcom *c;
> +     struct resource res;
> +     struct device *dev = &pdev->dev;
> +     void __iomem *en_base;
> +     int cpu, index = 0, ret;

Why initialize index here ?

> +
> +     c = devm_kzalloc(dev, sizeof(*c), GFP_KERNEL);

Check for a valid 'c' here ?

> +
> +     res = platform_get_resource_byname(dev, IORESOURCE_MEM, "en_base");

You are assigning a pointer to a structure here :(

> +     if (!res) {
> +             dev_err(dev, "Enable base not defined for %s\n", np->name);
> +             return ret;
> +     }
> +
> +     en_base = devm_ioremap(dev, res->start, resource_size(res));

You don't get a build error for doing res->start here ? Looks like you
sent a driver upstream which doesn't even build.

> +     if (!en_base) {
> +             dev_err(dev, "Unable to map %s en-base\n", np->name);
> +             return -ENOMEM;
> +     }
> +
> +     /* FW should be enabled state to proceed */
> +     if (!(readl_relaxed(en_base) & 0x1)) {
> +             dev_err(dev, "%s firmware not enabled\n", np->name);
> +             return -ENODEV;
> +     }
> +
> +     devm_iounmap(&pdev->dev, en_base);
> +
> +     index = of_property_match_string(np, "reg-names", "perf_base");
> +     if (index < 0)
> +             return index;
> +
> +     if (of_address_to_resource(np, index, &res))
> +             return -ENOMEM;
> +
> +     c->perf_base = devm_ioremap(dev, res.start, resource_size(&res));
> +     if (!c->perf_base) {
> +             dev_err(dev, "Unable to map %s perf-base\n", np->name);
> +             return -ENOMEM;
> +     }
> +
> +     index = of_property_match_string(np, "reg-names", "lut_base");
> +     if (index < 0)
> +             return index;
> +
> +     if (of_address_to_resource(np, index, &res))
> +             return -ENOMEM;
> +
> +     c->lut_base = devm_ioremap(dev, res.start, resource_size(&res));
> +     if (!c->lut_base) {
> +             dev_err(dev, "Unable to map %s lut-base\n", np->name);
> +             return -ENOMEM;
> +     }
> +
> +     ret = qcom_get_related_cpus(np, &c->related_cpus);
> +     if (ret) {
> +             dev_err(dev, "%s failed to get core phandles\n", np->name);
> +             return ret;
> +     }
> +
> +     c->max_cores = cpumask_weight(&c->related_cpus);
> +
> +     ret = qcom_read_lut(pdev, c);
> +     if (ret) {
> +             dev_err(dev, "%s failed to read LUT\n", np->name);
> +             return ret;
> +     }
> +
> +     for_each_cpu(cpu, &c->related_cpus)
> +             qcom_freq_domain_map[cpu] = c;
> +
> +     return 0;
> +}
> +
> +static int qcom_resources_init(struct platform_device *pdev)
> +{
> +     struct device_node *np;
> +     int ret = -ENODEV;
> +
> +     for_each_available_child_of_node(pdev->dev.of_node, np) {
> +             if (of_device_is_compatible(np, "cpufreq")) {
> +                     ret = qcom_cpu_resources_init(pdev, np);
> +                     if (ret)
> +                             return ret;
> +             }
> +     }
> +
> +     return ret;

Don't initialize ret to -ENODEV, rather return -ENODEV directly here.
That makes it more readable.

> +}
> +
> +static int qcom_cpufreq_fw_driver_probe(struct platform_device *pdev)
> +{
> +     int rc = 0;

Don't need to initialize to 0 here.

> +
> +     /* Get the bases of cpufreq for domains */
> +     rc = qcom_resources_init(pdev);
> +     if (rc) {
> +             dev_err(&pdev->dev, "CPUFreq resource init failed\n");
> +             return rc;
> +     }
> +
> +     rc = cpufreq_register_driver(&cpufreq_qcom_fw_driver);
> +     if (rc) {
> +             dev_err(&pdev->dev, "CPUFreq FW driver failed to register\n");
> +             return rc;
> +     }
> +
> +     dev_info(&pdev->dev, "QCOM CPUFreq FW driver inited\n");
> +
> +     return 0;
> +}
> +
> +static const struct of_device_id match_table[] = {
> +     { .compatible = "qcom,cpufreq-fw" },
> +     {}
> +};
> +
> +static struct platform_driver qcom_cpufreq_fw_driver = {
> +     .probe = qcom_cpufreq_fw_driver_probe,
> +     .driver = {
> +             .name = "qcom-cpufreq-fw",
> +             .of_match_table = match_table,
> +             .owner = THIS_MODULE,
> +     },
> +};
> +
> +static int __init qcom_cpufreq_fw_init(void)
> +{
> +     return platform_driver_register(&qcom_cpufreq_fw_driver);
> +}
> +subsys_initcall(qcom_cpufreq_fw_init);

Why this for a driver which can be built as a module ? You really want
it to be built as a module ?

> +
> +static void __exit qcom_cpufreq_fw_exit(void)
> +{
> +     platform_driver_unregister(&qcom_cpufreq_fw_driver);
> +}

But you don't unregister the cpufreq driver ?

> +module_exit(qcom_cpufreq_fw_exit);
> +
> +MODULE_DESCRIPTION("QCOM CPU Frequency FW");
> +MODULE_LICENSE("GPL v2");
> --
> Qualcomm INDIA, on behalf of Qualcomm Innovation Center, Inc.is a member
> of the Code Aurora Forum, hosted by the  Linux Foundation.

-- 
viresh

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