feat(cpufreq): RK3588 ondemand CPU DVFS with voltage calibration

components/axcpu/src/aarch64/init.rs

@@ -118,6 +118,19 @@ pub fn init_trap() {
     #[cfg(feature = "uspace")]
     {
         CNTKCTL_EL1.modify(CNTKCTL_EL1::EL0VCTEN::TrappedNone + CNTKCTL_EL1::EL0PCTEN::TrappedNone);
+        // Start this CPU's free-running PMU cycle counter and let EL0 read it, so
+        // `PMCCNTR_EL0` yields real cycle counts at both EL1 and EL0. This is the
+        // exact-frequency oracle the DVFS calibration reads in-kernel and that
+        // `cpuprobe`'s `mhz_pmc` reads from userspace (both were 0/trapping before,
+        // because these registers were only ever set on the lazy perf_event_open
+        // path). Guarded on PMUv3 being present; a live system-wide `perf stat -e
+        // cycles` may momentarily reset/disable this shared counter, which is fine
+        // for a boot/idle calibration.
+        if crate::pmu::probe().is_some() {
+            crate::pmu::init_cpu();
+            crate::pmu::cycles::configure(false, false);
+            crate::pmu::cycles::enable();
+        }
         barrier::isb(barrier::SY);
     }
     unsafe extern "C" {

drivers/ax-driver/Cargo.toml

@@ -136,6 +136,12 @@ rockchip-soc = [
     "dep:rdif-reset",
     "dep:rockchip-soc",
 ]
+# RK3588 fixed-OPP-at-boot CPU DVFS (voltage-free rung): raises the CPU cluster
+# clocks via the SCMI seam at probe time. Board-only policy; keep it opt-in.
+rk3588-cpufreq = [
+    "rockchip-soc",
+    "dep:arm-scmi-rs",
+]
 rockchip-pm = ["rockchip-soc", "dep:rdif-power", "dep:rockchip-pm"]
 list-pci-devices = ["pci"]
 pci-list-devices = ["list-pci-devices"]

drivers/ax-driver/src/lib.rs

@@ -95,6 +95,44 @@ pub mod usb;
 #[cfg(virtio_dev)]
 pub mod virtio;
 
+/// RK3588 CPU DVFS ondemand governor, exposed as a stable, arch-neutral entry
+/// the kernel can drive from a periodic task without knowing the SoC specifics.
+///
+/// The governor's *policy + apply* live in the (arch-specific) cpufreq driver,
+/// but its *loop* — sleeping between samples and reading the per-CPU busy
+/// counters — cannot live in this crate: ax-driver sits below ax-task/ax-hal in
+/// the dependency graph, so spawning a task here would be a cyclic dependency.
+/// The kernel therefore owns the loop and calls [`cpufreq::governor_poll`] each
+/// tick. When the DVFS feature is off these are no-ops so callers stay generic.
+pub mod cpufreq {
+    #[cfg(feature = "rk3588-cpufreq")]
+    pub use crate::soc::rockchip::cpufreq::{
+        calibrate_cluster, calibrate_wanted, governor_period_ms, governor_poll, governor_wanted,
+    };
+
+    /// Feature-off stub: no governor, so the kernel never spawns its task.
+    #[cfg(not(feature = "rk3588-cpufreq"))]
+    pub fn governor_wanted() -> bool {
+        false
+    }
+    /// Feature-off stub.
+    #[cfg(not(feature = "rk3588-cpufreq"))]
+    pub fn governor_period_ms() -> u64 {
+        100
+    }
+    /// Feature-off stub.
+    #[cfg(not(feature = "rk3588-cpufreq"))]
+    pub fn governor_poll(_busy: &[u64]) {}
+    /// Feature-off stub: no calibration.
+    #[cfg(not(feature = "rk3588-cpufreq"))]
+    pub fn calibrate_wanted() -> bool {
+        false
+    }
+    /// Feature-off stub.
+    #[cfg(not(feature = "rk3588-cpufreq"))]
+    pub fn calibrate_cluster(_cluster_idx: usize, _intended_cpu: usize) {}
+}
+
 #[cfg(feature = "pci")]
 pub use binding_info::PciIrqRequirement;
 pub use binding_info::{BindingInfo, BindingIrq, BindingIrqBinding, BindingIrqSource, FdtIrqSpec};

drivers/ax-driver/src/soc/mod.rs

@@ -15,8 +15,8 @@
 #[cfg(feature = "pinctrl")]
 mod fixed_regulator;
 #[cfg(feature = "rockchip-soc")]
-mod rockchip;
-#[cfg(feature = "rockchip-dwmmc")]
+pub(crate) mod rockchip;
+#[cfg(any(feature = "rockchip-dwmmc", feature = "rk3588-cpufreq"))]
 pub mod scmi;
 #[cfg(feature = "starfive-soc")]
 mod starfive;