Messages in this thread | | | Subject | Re: [PATCH 2/2] cpufreq: qcom-fw: Add support for QCOM cpufreq FW driver | From | Taniya Das <> | Date | Thu, 7 Jun 2018 12:48:20 +0530 |
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Hello Viresh,
Thank you for the review comments.
On 6/6/2018 11:31 AM, Viresh Kumar wrote: > On 04-06-18, 16:16, Taniya Das wrote: >> The CPUfreq FW present in some QCOM chipsets offloads the steps necessary >> for changing the frequency of CPUs. The driver implements the cpufreq >> driver interface for this firmware. >> >> Signed-off-by: Saravana Kannan <skannan@codeaurora.org> >> Signed-off-by: Taniya Das <tdas@codeaurora.org> >> --- >> drivers/cpufreq/Kconfig.arm | 9 ++ >> drivers/cpufreq/Makefile | 1 + >> drivers/cpufreq/qcom-cpufreq-fw.c | 316 ++++++++++++++++++++++++++++++++++++++ >> 3 files changed, 326 insertions(+) >> create mode 100644 drivers/cpufreq/qcom-cpufreq-fw.c >> >> diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm >> index c7ce928..82c391e 100644 >> --- a/drivers/cpufreq/Kconfig.arm >> +++ b/drivers/cpufreq/Kconfig.arm >> @@ -312,3 +312,12 @@ config ARM_PXA2xx_CPUFREQ >> This add the CPUFreq driver support for Intel PXA2xx SOCs. >> >> If in doubt, say N. >> + >> +config ARM_QCOM_CPUFREQ_FW >> + bool "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 fb4a2ec..34691a2 100644 >> --- a/drivers/cpufreq/Makefile >> +++ b/drivers/cpufreq/Makefile >> @@ -86,6 +86,7 @@ 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..2135a08 >> --- /dev/null >> +++ b/drivers/cpufreq/qcom-cpufreq-fw.c >> @@ -0,0 +1,316 @@ >> +// 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; >> + >> + writel_relaxed(index, c->perf_base); >> + >> + 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 0; >> + >> + 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; >> + >> + 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->freq_table = c->table; >> + policy->driver_data = c; > > What about fast cpufreq switching ? I think you can enable that option as well > here.. > Sure I will take a look and update.
>> + >> + return 0; >> +} >> + >> +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, > > What about CPU hotplug ? We can still do that, right ? So what will happen if > all CPUs of a freq-domain are removed (hence cpufreq policy is removed) and then > someone calls qcom_cpufreq_fw_get() ? You should really work on cpufreq_policy > there to get 'c'. >
You want the _get to do something as below. Please correct me if my understanding is wrong. ....
policy = cpufreq_cpu_get_raw(cpu); if (!policy) return 0;
c = policy->driver_data;
index = readl_relaxed(c->perf_base); index = min(index, LUT_MAX_ENTRIES - 1);
return c->table[index].frequency;
....
>> + .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, prev_freq, cur_freq; >> + >> + 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); >> + >> + if (!src) >> + c->table[i].frequency = INIT_RATE / 1000; >> + else >> + c->table[i].frequency = XO_RATE * lval / 1000; >> + >> + cur_freq = 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) >> + cur_freq = CPUFREQ_ENTRY_INVALID; >> + >> + /* >> + * Two of the same frequencies with the same core counts means >> + * end of table. >> + */ >> + if (i > 0 && c->table[i - 1].frequency == >> + c->table[i].frequency && prev_cc == core_count) { >> + struct cpufreq_frequency_table *prev = &c->table[i - 1]; >> + >> + if (prev_freq == CPUFREQ_ENTRY_INVALID) >> + prev->flags = CPUFREQ_BOOST_FREQ; >> + break; >> + } >> + prev_cc = core_count; >> + prev_freq = cur_freq; >> + } >> + >> + c->table[i].frequency = CPUFREQ_TABLE_END; >> + >> + return 0; >> +} > > Looks like there are many problems here. > - You are assigning prev_freq with cur_freq (which may be uninitialized local > variable here). > - In this version, you never write CPUFREQ_ENTRY_INVALID to table[i].frequency, > which looks wrong as well. >
- The code to detect boost, would only enter for i > 0 and the prev_freq would be initialized with the cur_freq. - In the case where the core_count != max_cores, the cur_freq is marked INVALID, and when both prev_freq == cur_freq && prev_cc && cur_cc match, that is the time the prev table flags need to be updated. Marking the table[i].frequency as INVALID is not required as cur_freq is already marked with the same. Please correct me if you think otherwise.
>> + >> +static int qcom_get_related_cpus(struct device_node *np, struct cpumask *m) >> +{ >> + struct device_node *cpu_dev; > > s/cpu_dev/cpu_np/ > >> + int cpu; >> + >> + for_each_possible_cpu(cpu) { >> + cpu_dev = of_cpu_device_node_get(cpu); >> + if (!cpu_dev) >> + continue; >> + cpu_dev = of_parse_phandle(cpu_dev, "qcom,freq-domain", 0); > > What's returned here is a pointer to the qcom,freq-domain node, and you assign > that to a variable named cpu_dev. Either use two variables for different node > types, or rename it to temp_np or something similar. >
I would use a different node.
>> + if (!cpu_dev) >> + continue; >> + if (cpu_dev == np) >> + cpumask_set_cpu(cpu, m); >> + } >> + >> + if (cpumask_empty(m)) >> + return -ENOENT; >> + >> + return 0; >> +} >> + >> +static int qcom_cpu_resources_init(struct platform_device *pdev, >> + struct device_node *np) >> +{ >> + struct cpufreq_qcom *c; >> + struct resource res; >> + struct device *dev = &pdev->dev; >> + void __iomem *en_base; >> + int cpu, index, ret; >> + >> + c = devm_kzalloc(dev, sizeof(*c), GFP_KERNEL); >> + if (!c) >> + return -ENOMEM; >> + >> + index = of_property_match_string(np, "reg-names", "enable"); >> + if (index < 0) >> + return index; >> + >> + if (of_address_to_resource(np, index, &res)) >> + return -ENOMEM; >> + >> + en_base = devm_ioremap(dev, res.start, resource_size(&res)); >> + if (!en_base) { >> + dev_err(dev, "Unable to map %s enable-base\n", np->name); >> + return -ENOMEM; >> + } >> + >> + /* FW should be in 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"); >> + 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"); >> + 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); > > Maybe write a more relevant error message here ? >
Sure, would take care of it in the next patch.
>> + return ret; >> + } >> + >> + c->max_cores = cpumask_weight(&c->related_cpus); > > Maybe remove the error checking conditional from qcom_get_related_cpus() and > check !c->max_cores here for the same. >
I would update it in the next patch.
>> + >> + ret = qcom_read_lut(pdev, c); >> + if (ret) { >> + dev_err(dev, "%s failed to read LUT\n", np->name); >> + return ret; >> + } > > Enter a blank line here.
I would update in the next patch. > >> + for_each_cpu(cpu, &c->related_cpus) >> + qcom_freq_domain_map[cpu] = c; > > This whole setup looks a bit confusing to me. This is what you are doing > essentially: > > qcom_resources_init() > { > for_each_possible_cpu() { > qcom_cpu_resources_init() > { > populate c->related_cpus; > > for_each_related_cpu() { > qcom_freq_domain_map[cpu] = c; > } > } > } > } > > So if there are 4 CPUs that share a freq domain, then you are allocating 'c' 4 > times and (over)writing qcom_freq_domain_map[] for all these CPUs 4 times and > finally keeping value of 'c' only once. > > You must be running most of the work done in qcom_resources_init() only once per > freq-domain. >
Thanks, you are correct, I carried the earlier logic, would cleanup in the next patch.
>> + >> + return 0; >> +} >> + >> +static int qcom_resources_init(struct platform_device *pdev) >> +{ >> + struct device_node *np, *cpu_dev; > > cpu_dev is normally used in kernel for struct device *, maybe use cpu_np ?
I would update it in the next patch. > >> + unsigned int cpu; >> + int ret; >> + >> + for_each_possible_cpu(cpu) { >> + cpu_dev = of_cpu_device_node_get(cpu); >> + if (!cpu_dev) { >> + dev_err(&pdev->dev, "Failed to get cpu %d device\n", >> + cpu); >> + continue; >> + } >> + >> + np = of_parse_phandle(cpu_dev, "qcom,freq-domain", 0); >> + if (!np) { >> + dev_err(&pdev->dev, "Failed to get freq-domain device\n"); >> + continue; > > I am not sure if we should continue or error out here. Why would you want only a > group of CPUs to have this property set ? Or if you really have a case for that > currently ? >
I don't have any usecase, but I was of the opinion in case there is no freq domains attached to a cluster. But it might be better I error out.
>> + } >> + >> + of_node_put(cpu_dev); >> + >> + ret = qcom_cpu_resources_init(pdev, np); >> + if (ret) >> + return ret; >> + } >> + >> + return 0; >> +} >> + >> +static int qcom_cpufreq_fw_driver_probe(struct platform_device *pdev) >> +{ >> + int rc; >> + >> + /* 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"); > > s/inited/initialized/ ? >
Sure, will fix in the next patch.
>> + >> + 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); >> + >> +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. >
-- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation.
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