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Diffstat (limited to 'drivers/cpufreq/rcpufreq_dt.rs')
| -rw-r--r-- | drivers/cpufreq/rcpufreq_dt.rs | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/drivers/cpufreq/rcpufreq_dt.rs b/drivers/cpufreq/rcpufreq_dt.rs new file mode 100644 index 000000000000..94ed81644fe1 --- /dev/null +++ b/drivers/cpufreq/rcpufreq_dt.rs @@ -0,0 +1,226 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Rust based implementation of the cpufreq-dt driver. + +use kernel::{ + c_str, + clk::Clk, + cpu, cpufreq, + cpumask::CpumaskVar, + device::{Core, Device}, + error::code::*, + fmt, + macros::vtable, + module_platform_driver, of, opp, platform, + prelude::*, + str::CString, + sync::Arc, +}; + +/// Finds exact supply name from the OF node. +fn find_supply_name_exact(dev: &Device, name: &str) -> Option<CString> { + let prop_name = CString::try_from_fmt(fmt!("{}-supply", name)).ok()?; + dev.property_present(&prop_name) + .then(|| CString::try_from_fmt(fmt!("{name}")).ok()) + .flatten() +} + +/// Finds supply name for the CPU from DT. +fn find_supply_names(dev: &Device, cpu: u32) -> Option<KVec<CString>> { + // Try "cpu0" for older DTs, fallback to "cpu". + let name = (cpu == 0) + .then(|| find_supply_name_exact(dev, "cpu0")) + .flatten() + .or_else(|| find_supply_name_exact(dev, "cpu"))?; + + let mut list = KVec::with_capacity(1, GFP_KERNEL).ok()?; + list.push(name, GFP_KERNEL).ok()?; + + Some(list) +} + +/// Represents the cpufreq dt device. +struct CPUFreqDTDevice { + opp_table: opp::Table, + freq_table: opp::FreqTable, + _mask: CpumaskVar, + _token: Option<opp::ConfigToken>, + _clk: Clk, +} + +#[derive(Default)] +struct CPUFreqDTDriver; + +#[vtable] +impl opp::ConfigOps for CPUFreqDTDriver {} + +#[vtable] +impl cpufreq::Driver for CPUFreqDTDriver { + const NAME: &'static CStr = c_str!("cpufreq-dt"); + const FLAGS: u16 = cpufreq::flags::NEED_INITIAL_FREQ_CHECK | cpufreq::flags::IS_COOLING_DEV; + const BOOST_ENABLED: bool = true; + + type PData = Arc<CPUFreqDTDevice>; + + fn init(policy: &mut cpufreq::Policy) -> Result<Self::PData> { + let cpu = policy.cpu(); + // SAFETY: The CPU device is only used during init; it won't get hot-unplugged. The cpufreq + // core registers with CPU notifiers and the cpufreq core/driver won't use the CPU device, + // once the CPU is hot-unplugged. + let dev = unsafe { cpu::from_cpu(cpu)? }; + let mut mask = CpumaskVar::new_zero(GFP_KERNEL)?; + + mask.set(cpu); + + let token = find_supply_names(dev, cpu) + .map(|names| { + opp::Config::<Self>::new() + .set_regulator_names(names)? + .set(dev) + }) + .transpose()?; + + // Get OPP-sharing information from "operating-points-v2" bindings. + let fallback = match opp::Table::of_sharing_cpus(dev, &mut mask) { + Ok(()) => false, + Err(e) if e == ENOENT => { + // "operating-points-v2" not supported. If the platform hasn't + // set sharing CPUs, fallback to all CPUs share the `Policy` + // for backward compatibility. + opp::Table::sharing_cpus(dev, &mut mask).is_err() + } + Err(e) => return Err(e), + }; + + // Initialize OPP tables for all policy cpus. + // + // For platforms not using "operating-points-v2" bindings, we do this + // before updating policy cpus. Otherwise, we will end up creating + // duplicate OPPs for the CPUs. + // + // OPPs might be populated at runtime, don't fail for error here unless + // it is -EPROBE_DEFER. + let mut opp_table = match opp::Table::from_of_cpumask(dev, &mut mask) { + Ok(table) => table, + Err(e) => { + if e == EPROBE_DEFER { + return Err(e); + } + + // The table is added dynamically ? + opp::Table::from_dev(dev)? + } + }; + + // The OPP table must be initialized, statically or dynamically, by this point. + opp_table.opp_count()?; + + // Set sharing cpus for fallback scenario. + if fallback { + mask.setall(); + opp_table.set_sharing_cpus(&mut mask)?; + } + + let mut transition_latency = opp_table.max_transition_latency_ns() as u32; + if transition_latency == 0 { + transition_latency = cpufreq::ETERNAL_LATENCY_NS; + } + + policy + .set_dvfs_possible_from_any_cpu(true) + .set_suspend_freq(opp_table.suspend_freq()) + .set_transition_latency_ns(transition_latency); + + let freq_table = opp_table.cpufreq_table()?; + // SAFETY: The `freq_table` is not dropped while it is getting used by the C code. + unsafe { policy.set_freq_table(&freq_table) }; + + // SAFETY: The returned `clk` is not dropped while it is getting used by the C code. + let clk = unsafe { policy.set_clk(dev, None)? }; + + mask.copy(policy.cpus()); + + Ok(Arc::new( + CPUFreqDTDevice { + opp_table, + freq_table, + _mask: mask, + _token: token, + _clk: clk, + }, + GFP_KERNEL, + )?) + } + + fn exit(_policy: &mut cpufreq::Policy, _data: Option<Self::PData>) -> Result { + Ok(()) + } + + fn online(_policy: &mut cpufreq::Policy) -> Result { + // We did light-weight tear down earlier, nothing to do here. + Ok(()) + } + + fn offline(_policy: &mut cpufreq::Policy) -> Result { + // Preserve policy->data and don't free resources on light-weight + // tear down. + Ok(()) + } + + fn suspend(policy: &mut cpufreq::Policy) -> Result { + policy.generic_suspend() + } + + fn verify(data: &mut cpufreq::PolicyData) -> Result { + data.generic_verify() + } + + fn target_index(policy: &mut cpufreq::Policy, index: cpufreq::TableIndex) -> Result { + let Some(data) = policy.data::<Self::PData>() else { + return Err(ENOENT); + }; + + let freq = data.freq_table.freq(index)?; + data.opp_table.set_rate(freq) + } + + fn get(policy: &mut cpufreq::Policy) -> Result<u32> { + policy.generic_get() + } + + fn set_boost(_policy: &mut cpufreq::Policy, _state: i32) -> Result { + Ok(()) + } + + fn register_em(policy: &mut cpufreq::Policy) { + policy.register_em_opp() + } +} + +kernel::of_device_table!( + OF_TABLE, + MODULE_OF_TABLE, + <CPUFreqDTDriver as platform::Driver>::IdInfo, + [(of::DeviceId::new(c_str!("operating-points-v2")), ())] +); + +impl platform::Driver for CPUFreqDTDriver { + type IdInfo = (); + const OF_ID_TABLE: Option<of::IdTable<Self::IdInfo>> = Some(&OF_TABLE); + + fn probe( + pdev: &platform::Device<Core>, + _id_info: Option<&Self::IdInfo>, + ) -> Result<Pin<KBox<Self>>> { + cpufreq::Registration::<CPUFreqDTDriver>::new_foreign_owned(pdev.as_ref())?; + Ok(KBox::new(Self {}, GFP_KERNEL)?.into()) + } +} + +module_platform_driver! { + type: CPUFreqDTDriver, + name: "cpufreq-dt", + author: "Viresh Kumar <viresh.kumar@linaro.org>", + description: "Generic CPUFreq DT driver", + license: "GPL v2", +} |