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| 1 | +// SPDX-License-Identifier: GPL-2.0 |
| 2 | + |
| 3 | +//! Rust based implementation of the cpufreq-dt driver. |
| 4 | +
|
| 5 | +use kernel::{ |
| 6 | + c_str, |
| 7 | + clk::Clk, |
| 8 | + cpu, cpufreq, |
| 9 | + cpumask::CpumaskVar, |
| 10 | + device::{Core, Device}, |
| 11 | + error::code::*, |
| 12 | + fmt, |
| 13 | + macros::vtable, |
| 14 | + module_platform_driver, of, opp, platform, |
| 15 | + prelude::*, |
| 16 | + str::CString, |
| 17 | + sync::Arc, |
| 18 | +}; |
| 19 | + |
| 20 | +/// Finds exact supply name from the OF node. |
| 21 | +fn find_supply_name_exact(dev: &Device, name: &str) -> Option<CString> { |
| 22 | + let prop_name = CString::try_from_fmt(fmt!("{}-supply", name)).ok()?; |
| 23 | + dev.property_present(&prop_name) |
| 24 | + .then(|| CString::try_from_fmt(fmt!("{name}")).ok()) |
| 25 | + .flatten() |
| 26 | +} |
| 27 | + |
| 28 | +/// Finds supply name for the CPU from DT. |
| 29 | +fn find_supply_names(dev: &Device, cpu: u32) -> Option<KVec<CString>> { |
| 30 | + // Try "cpu0" for older DTs, fallback to "cpu". |
| 31 | + let name = (cpu == 0) |
| 32 | + .then(|| find_supply_name_exact(dev, "cpu0")) |
| 33 | + .flatten() |
| 34 | + .or_else(|| find_supply_name_exact(dev, "cpu"))?; |
| 35 | + |
| 36 | + let mut list = KVec::with_capacity(1, GFP_KERNEL).ok()?; |
| 37 | + list.push(name, GFP_KERNEL).ok()?; |
| 38 | + |
| 39 | + Some(list) |
| 40 | +} |
| 41 | + |
| 42 | +/// Represents the cpufreq dt device. |
| 43 | +struct CPUFreqDTDevice { |
| 44 | + opp_table: opp::Table, |
| 45 | + freq_table: opp::FreqTable, |
| 46 | + _mask: CpumaskVar, |
| 47 | + _token: Option<opp::ConfigToken>, |
| 48 | + _clk: Clk, |
| 49 | +} |
| 50 | + |
| 51 | +#[derive(Default)] |
| 52 | +struct CPUFreqDTDriver; |
| 53 | + |
| 54 | +#[vtable] |
| 55 | +impl opp::ConfigOps for CPUFreqDTDriver {} |
| 56 | + |
| 57 | +#[vtable] |
| 58 | +impl cpufreq::Driver for CPUFreqDTDriver { |
| 59 | + const NAME: &'static CStr = c_str!("cpufreq-dt"); |
| 60 | + const FLAGS: u16 = cpufreq::flags::NEED_INITIAL_FREQ_CHECK | cpufreq::flags::IS_COOLING_DEV; |
| 61 | + const BOOST_ENABLED: bool = true; |
| 62 | + |
| 63 | + type PData = Arc<CPUFreqDTDevice>; |
| 64 | + |
| 65 | + fn init(policy: &mut cpufreq::Policy) -> Result<Self::PData> { |
| 66 | + let cpu = policy.cpu(); |
| 67 | + // SAFETY: The CPU device is only used during init; it won't get hot-unplugged. The cpufreq |
| 68 | + // core registers with CPU notifiers and the cpufreq core/driver won't use the CPU device, |
| 69 | + // once the CPU is hot-unplugged. |
| 70 | + let dev = unsafe { cpu::from_cpu(cpu)? }; |
| 71 | + let mut mask = CpumaskVar::new_zero(GFP_KERNEL)?; |
| 72 | + |
| 73 | + mask.set(cpu); |
| 74 | + |
| 75 | + let token = find_supply_names(dev, cpu) |
| 76 | + .map(|names| { |
| 77 | + opp::Config::<Self>::new() |
| 78 | + .set_regulator_names(names)? |
| 79 | + .set(dev) |
| 80 | + }) |
| 81 | + .transpose()?; |
| 82 | + |
| 83 | + // Get OPP-sharing information from "operating-points-v2" bindings. |
| 84 | + let fallback = match opp::Table::of_sharing_cpus(dev, &mut mask) { |
| 85 | + Ok(()) => false, |
| 86 | + Err(e) if e == ENOENT => { |
| 87 | + // "operating-points-v2" not supported. If the platform hasn't |
| 88 | + // set sharing CPUs, fallback to all CPUs share the `Policy` |
| 89 | + // for backward compatibility. |
| 90 | + opp::Table::sharing_cpus(dev, &mut mask).is_err() |
| 91 | + } |
| 92 | + Err(e) => return Err(e), |
| 93 | + }; |
| 94 | + |
| 95 | + // Initialize OPP tables for all policy cpus. |
| 96 | + // |
| 97 | + // For platforms not using "operating-points-v2" bindings, we do this |
| 98 | + // before updating policy cpus. Otherwise, we will end up creating |
| 99 | + // duplicate OPPs for the CPUs. |
| 100 | + // |
| 101 | + // OPPs might be populated at runtime, don't fail for error here unless |
| 102 | + // it is -EPROBE_DEFER. |
| 103 | + let mut opp_table = match opp::Table::from_of_cpumask(dev, &mut mask) { |
| 104 | + Ok(table) => table, |
| 105 | + Err(e) => { |
| 106 | + if e == EPROBE_DEFER { |
| 107 | + return Err(e); |
| 108 | + } |
| 109 | + |
| 110 | + // The table is added dynamically ? |
| 111 | + opp::Table::from_dev(dev)? |
| 112 | + } |
| 113 | + }; |
| 114 | + |
| 115 | + // The OPP table must be initialized, statically or dynamically, by this point. |
| 116 | + opp_table.opp_count()?; |
| 117 | + |
| 118 | + // Set sharing cpus for fallback scenario. |
| 119 | + if fallback { |
| 120 | + mask.setall(); |
| 121 | + opp_table.set_sharing_cpus(&mut mask)?; |
| 122 | + } |
| 123 | + |
| 124 | + let mut transition_latency = opp_table.max_transition_latency_ns() as u32; |
| 125 | + if transition_latency == 0 { |
| 126 | + transition_latency = cpufreq::ETERNAL_LATENCY_NS; |
| 127 | + } |
| 128 | + |
| 129 | + policy |
| 130 | + .set_dvfs_possible_from_any_cpu(true) |
| 131 | + .set_suspend_freq(opp_table.suspend_freq()) |
| 132 | + .set_transition_latency_ns(transition_latency); |
| 133 | + |
| 134 | + let freq_table = opp_table.cpufreq_table()?; |
| 135 | + // SAFETY: The `freq_table` is not dropped while it is getting used by the C code. |
| 136 | + unsafe { policy.set_freq_table(&freq_table) }; |
| 137 | + |
| 138 | + // SAFETY: The returned `clk` is not dropped while it is getting used by the C code. |
| 139 | + let clk = unsafe { policy.set_clk(dev, None)? }; |
| 140 | + |
| 141 | + mask.copy(policy.cpus()); |
| 142 | + |
| 143 | + Ok(Arc::new( |
| 144 | + CPUFreqDTDevice { |
| 145 | + opp_table, |
| 146 | + freq_table, |
| 147 | + _mask: mask, |
| 148 | + _token: token, |
| 149 | + _clk: clk, |
| 150 | + }, |
| 151 | + GFP_KERNEL, |
| 152 | + )?) |
| 153 | + } |
| 154 | + |
| 155 | + fn exit(_policy: &mut cpufreq::Policy, _data: Option<Self::PData>) -> Result { |
| 156 | + Ok(()) |
| 157 | + } |
| 158 | + |
| 159 | + fn online(_policy: &mut cpufreq::Policy) -> Result { |
| 160 | + // We did light-weight tear down earlier, nothing to do here. |
| 161 | + Ok(()) |
| 162 | + } |
| 163 | + |
| 164 | + fn offline(_policy: &mut cpufreq::Policy) -> Result { |
| 165 | + // Preserve policy->data and don't free resources on light-weight |
| 166 | + // tear down. |
| 167 | + Ok(()) |
| 168 | + } |
| 169 | + |
| 170 | + fn suspend(policy: &mut cpufreq::Policy) -> Result { |
| 171 | + policy.generic_suspend() |
| 172 | + } |
| 173 | + |
| 174 | + fn verify(data: &mut cpufreq::PolicyData) -> Result { |
| 175 | + data.generic_verify() |
| 176 | + } |
| 177 | + |
| 178 | + fn target_index(policy: &mut cpufreq::Policy, index: cpufreq::TableIndex) -> Result { |
| 179 | + let Some(data) = policy.data::<Self::PData>() else { |
| 180 | + return Err(ENOENT); |
| 181 | + }; |
| 182 | + |
| 183 | + let freq = data.freq_table.freq(index)?; |
| 184 | + data.opp_table.set_rate(freq) |
| 185 | + } |
| 186 | + |
| 187 | + fn get(policy: &mut cpufreq::Policy) -> Result<u32> { |
| 188 | + policy.generic_get() |
| 189 | + } |
| 190 | + |
| 191 | + fn set_boost(_policy: &mut cpufreq::Policy, _state: i32) -> Result { |
| 192 | + Ok(()) |
| 193 | + } |
| 194 | + |
| 195 | + fn register_em(policy: &mut cpufreq::Policy) { |
| 196 | + policy.register_em_opp() |
| 197 | + } |
| 198 | +} |
| 199 | + |
| 200 | +kernel::of_device_table!( |
| 201 | + OF_TABLE, |
| 202 | + MODULE_OF_TABLE, |
| 203 | + <CPUFreqDTDriver as platform::Driver>::IdInfo, |
| 204 | + [(of::DeviceId::new(c_str!("operating-points-v2")), ())] |
| 205 | +); |
| 206 | + |
| 207 | +impl platform::Driver for CPUFreqDTDriver { |
| 208 | + type IdInfo = (); |
| 209 | + const OF_ID_TABLE: Option<of::IdTable<Self::IdInfo>> = Some(&OF_TABLE); |
| 210 | + |
| 211 | + fn probe( |
| 212 | + pdev: &platform::Device<Core>, |
| 213 | + _id_info: Option<&Self::IdInfo>, |
| 214 | + ) -> Result<Pin<KBox<Self>>> { |
| 215 | + cpufreq::Registration::<CPUFreqDTDriver>::new_foreign_owned(pdev.as_ref())?; |
| 216 | + Ok(KBox::new(Self {}, GFP_KERNEL)?.into()) |
| 217 | + } |
| 218 | +} |
| 219 | + |
| 220 | +module_platform_driver! { |
| 221 | + type: CPUFreqDTDriver, |
| 222 | + name: "cpufreq-dt", |
| 223 | + author: "Viresh Kumar <viresh.kumar@linaro.org>", |
| 224 | + description: "Generic CPUFreq DT driver", |
| 225 | + license: "GPL v2", |
| 226 | +} |
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