[RFC,V2,2/8] rust: Extend OPP bindings for the OPP table

diff --git a/rust/kernel/opp.rs b/rust/kernel/opp.rs
index 9e5cf0412ed5..06f36845047f 100644
--- a/rust/kernel/opp.rs
+++ b/rust/kernel/opp.rs
@@ -7,9 +7,9 @@ 
 //! C header: [`include/linux/pm_opp.h`](../../../../../../include/linux/pm_opp.h)
 
 use crate::{
-    bindings,
+    bindings, cpumask,
     device::Device,
-    error::{code::*, to_result, Result},
+    error::{code::*, from_err_ptr, to_result, Error, Result},
     types::{ARef, AlwaysRefCounted, Opaque},
 };
 
@@ -31,6 +31,376 @@  pub fn new(freq: u64, u_volt: u64, level: u32, turbo: bool) -> Self {
     }
 }
 
+/// OPP search types.
+#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+pub enum SearchType {
+    /// Search for exact value.
+    Exact,
+    /// Search for highest value less than equal to value.
+    Floor,
+    /// Search for lowest value greater than equal to value.
+    Ceil,
+}
+
+/// Operating performance point (OPP) table.
+///
+/// # Invariants
+///
+/// The pointer stored in `Self` is non-null and valid for the lifetime of the ARef instance. In
+/// particular, the ARef instance owns an increment on underlying object’s reference count.
+pub struct Table {
+    ptr: *mut bindings::opp_table,
+    dev: ARef<Device>,
+    em: bool,
+    of: bool,
+    cpumask: Option<cpumask::Cpumask>,
+}
+
+// SAFETY: The fields of `Table` are safe to be used from any thread.
+unsafe impl Send for Table {}
+
+// SAFETY: The fields of `Table` are safe to be referenced from any thread.
+unsafe impl Sync for Table {}
+
+impl Table {
+    /// Creates a new OPP table instance from raw pointer.
+    ///
+    /// # Safety
+    ///
+    /// Callers must ensure that `ptr` is valid and non-null.
+    unsafe fn from_ptr(ptr: *mut bindings::opp_table, dev: ARef<Device>) -> Self {
+        // SAFETY: By the safety requirements, ptr is valid and its refcount will be incremented.
+        unsafe { bindings::dev_pm_opp_get_opp_table_ref(ptr) };
+
+        Self {
+            ptr,
+            dev,
+            em: false,
+            of: false,
+            cpumask: None,
+        }
+    }
+
+    /// Find OPP table from device.
+    pub fn from_dev(dev: ARef<Device>) -> Result<Self> {
+        // SAFETY: The requirements are satisfied by the existence of `Device` and its safety
+        // requirements. Refcount of the OPP table is incremented as well.
+        let ptr = from_err_ptr(unsafe { bindings::dev_pm_opp_get_opp_table(dev.as_raw()) })?;
+
+        Ok(Self {
+            ptr,
+            dev: dev.clone(),
+            em: false,
+            of: false,
+            cpumask: None,
+        })
+    }
+
+    /// Add device tree based OPP table for the device.
+    #[cfg(CONFIG_OF)]
+    pub fn from_of(dev: ARef<Device>, index: i32) -> Result<Self> {
+        // SAFETY: The requirements are satisfied by the existence of `Device` and its safety
+        // requirements. Refcount of the OPP table is incremented as well.
+        to_result(unsafe { bindings::dev_pm_opp_of_add_table_indexed(dev.as_raw(), index) })?;
+
+        // Fetch the newly created table.
+        let mut table = Self::from_dev(dev)?;
+        table.of = true;
+
+        Ok(table)
+    }
+
+    // Remove device tree based OPP table for the device.
+    #[cfg(CONFIG_OF)]
+    fn remove_of(&self) {
+        // SAFETY: The requirements are satisfied by the existence of `Device` and its safety
+        // requirements. We took the reference from `from_of` earlier, it is safe to drop the same
+        // now.
+        unsafe { bindings::dev_pm_opp_of_remove_table(self.dev.as_raw()) };
+    }
+
+    /// Add device tree based OPP table for CPU devices.
+    #[cfg(CONFIG_OF)]
+    pub fn from_of_cpumask(dev: ARef<Device>, cpumask: &mut cpumask::Cpumask) -> Result<Self> {
+        // SAFETY: The cpumask is valid and the returned ptr will be owned by the [`Table`] instance.
+        to_result(unsafe { bindings::dev_pm_opp_of_cpumask_add_table(cpumask.as_ptr()) })?;
+
+        // Fetch the newly created table.
+        let mut table = Self::from_dev(dev)?;
+        // SAFETY: The `cpumask` is guaranteed by the C code to be valid.
+        table.cpumask = Some(unsafe { cpumask::Cpumask::new(cpumask.as_mut_ptr()) });
+
+        Ok(table)
+    }
+
+    // Remove device tree based OPP table for CPU devices.
+    #[cfg(CONFIG_OF)]
+    fn remove_of_cpumask(&self, cpumask: &cpumask::Cpumask) {
+        // SAFETY: The cpumask is valid and we took the reference from `from_of_cpumask` earlier,
+        // it is safe to drop the same now.
+        unsafe { bindings::dev_pm_opp_of_cpumask_remove_table(cpumask.as_ptr()) };
+    }
+
+    /// Returns the number of OPPs in the table.
+    pub fn opp_count(&self) -> Result<u32> {
+        // SAFETY: The requirements are satisfied by the existence of `Device` and its safety
+        // requirements.
+        let ret = unsafe { bindings::dev_pm_opp_get_opp_count(self.dev.as_raw()) };
+        if ret < 0 {
+            Err(Error::from_errno(ret))
+        } else {
+            Ok(ret as u32)
+        }
+    }
+
+    /// Returns max clock latency of the OPPs in the table.
+    pub fn max_clock_latency(&self) -> u64 {
+        // SAFETY: The requirements are satisfied by the existence of `Device` and its safety
+        // requirements.
+        unsafe { bindings::dev_pm_opp_get_max_clock_latency(self.dev.as_raw()) }
+    }
+
+    /// Returns max volt latency of the OPPs in the table.
+    pub fn max_volt_latency(&self) -> u64 {
+        // SAFETY: The requirements are satisfied by the existence of `Device` and its safety
+        // requirements.
+        unsafe { bindings::dev_pm_opp_get_max_volt_latency(self.dev.as_raw()) }
+    }
+
+    /// Returns max transition latency of the OPPs in the table.
+    pub fn max_transition_latency(&self) -> u64 {
+        // SAFETY: The requirements are satisfied by the existence of `Device` and its safety
+        // requirements.
+        unsafe { bindings::dev_pm_opp_get_max_transition_latency(self.dev.as_raw()) }
+    }
+
+    /// Returns the suspend OPP.
+    pub fn suspend_freq(&self) -> u64 {
+        // SAFETY: The requirements are satisfied by the existence of `Device` and its safety
+        // requirements.
+        unsafe { bindings::dev_pm_opp_get_suspend_opp_freq(self.dev.as_raw()) }
+    }
+
+    /// Synchronizes regulators used by the OPP table.
+    pub fn sync_regulators(&self) -> Result<()> {
+        // SAFETY: The requirements are satisfied by the existence of `Device` and its safety
+        // requirements.
+        to_result(unsafe { bindings::dev_pm_opp_sync_regulators(self.dev.as_raw()) })
+    }
+
+    /// Gets sharing CPUs.
+    pub fn sharing_cpus(dev: ARef<Device>, cpumask: &mut cpumask::Cpumask) -> Result<()> {
+        // SAFETY: The requirements are satisfied by the existence of `Device` and its safety
+        // requirements.
+        to_result(unsafe {
+            bindings::dev_pm_opp_get_sharing_cpus(dev.as_raw(), cpumask.as_mut_ptr())
+        })
+    }
+
+    /// Sets sharing CPUs.
+    pub fn set_sharing_cpus(&self, cpumask: &cpumask::Cpumask) -> Result<()> {
+        // SAFETY: The requirements are satisfied by the existence of `Device` and its safety
+        // requirements.
+        to_result(unsafe {
+            bindings::dev_pm_opp_set_sharing_cpus(self.dev.as_raw(), cpumask.as_ptr())
+        })
+    }
+
+    /// Gets sharing CPUs from Device tree.
+    #[cfg(CONFIG_OF)]
+    pub fn of_sharing_cpus(dev: ARef<Device>, cpumask: &mut cpumask::Cpumask) -> Result<()> {
+        // SAFETY: The requirements are satisfied by the existence of `Device` and its safety
+        // requirements.
+        to_result(unsafe {
+            bindings::dev_pm_opp_of_get_sharing_cpus(dev.as_raw(), cpumask.as_mut_ptr())
+        })
+    }
+
+    /// Updates the voltage value for an OPP.
+    pub fn adjust_voltage(
+        &self,
+        freq: u64,
+        u_volt: u64,
+        u_volt_min: u64,
+        u_volt_max: u64,
+    ) -> Result<()> {
+        // SAFETY: The requirements are satisfied by the existence of `Device` and its safety
+        // requirements.
+        to_result(unsafe {
+            bindings::dev_pm_opp_adjust_voltage(
+                self.dev.as_raw(),
+                freq,
+                u_volt,
+                u_volt_min,
+                u_volt_max,
+            )
+        })
+    }
+
+    /// Sets a matching OPP based on frequency.
+    pub fn set_rate(&self, freq: u64) -> Result<()> {
+        // SAFETY: The requirements are satisfied by the existence of `Device` and its safety
+        // requirements.
+        to_result(unsafe { bindings::dev_pm_opp_set_rate(self.dev.as_raw(), freq) })
+    }
+
+    /// Sets exact OPP.
+    pub fn set_opp(&self, opp: ARef<OPP>) -> Result<()> {
+        // SAFETY: The requirements are satisfied by the existence of `Device` and its safety
+        // requirements.
+        to_result(unsafe { bindings::dev_pm_opp_set_opp(self.dev.as_raw(), opp.as_mut_ptr()) })
+    }
+
+    /// Finds OPP based on frequency.
+    pub fn opp_from_freq(
+        &self,
+        mut freq: u64,
+        available: Option<bool>,
+        index: Option<u32>,
+        stype: SearchType,
+    ) -> Result<ARef<OPP>> {
+        let rdev = self.dev.as_raw();
+        let index = index.unwrap_or(0);
+
+        let ptr = from_err_ptr(match stype {
+            SearchType::Exact => {
+                if let Some(available) = available {
+                    // SAFETY: The requirements are satisfied by the existence of `Device` and
+                    // its safety requirements. The returned ptr will be owned by the new [`OPP`]
+                    // instance.
+                    unsafe {
+                        bindings::dev_pm_opp_find_freq_exact_indexed(rdev, freq, index, available)
+                    }
+                } else {
+                    return Err(EINVAL);
+                }
+            }
+
+            // SAFETY: The requirements are satisfied by the existence of `Device` and its
+            // safety requirements. The returned ptr will be owned by the new [`OPP`] instance.
+            SearchType::Ceil => unsafe {
+                bindings::dev_pm_opp_find_freq_ceil_indexed(rdev, &mut freq as *mut u64, index)
+            },
+
+            // SAFETY: The requirements are satisfied by the existence of `Device` and its
+            // safety requirements. The returned ptr will be owned by the new [`OPP`] instance.
+            SearchType::Floor => unsafe {
+                bindings::dev_pm_opp_find_freq_floor_indexed(rdev, &mut freq as *mut u64, index)
+            },
+        })?;
+
+        // SAFETY: The `ptr` is guaranteed by the C code to be valid.
+        unsafe { OPP::from_ptr_owned(ptr) }
+    }
+
+    /// Finds OPP based on level.
+    pub fn opp_from_level(&self, mut level: u32, stype: SearchType) -> Result<ARef<OPP>> {
+        let rdev = self.dev.as_raw();
+
+        let ptr = from_err_ptr(match stype {
+            // SAFETY: The requirements are satisfied by the existence of `Device` and its
+            // safety requirements. The returned ptr will be owned by the new [`OPP`] instance.
+            SearchType::Exact => unsafe { bindings::dev_pm_opp_find_level_exact(rdev, level) },
+
+            // SAFETY: The requirements are satisfied by the existence of `Device` and its
+            // safety requirements. The returned ptr will be owned by the new [`OPP`] instance.
+            SearchType::Ceil => unsafe {
+                bindings::dev_pm_opp_find_level_ceil(rdev, &mut level as *mut u32)
+            },
+
+            // SAFETY: The requirements are satisfied by the existence of `Device` and its
+            // safety requirements. The returned ptr will be owned by the new [`OPP`] instance.
+            SearchType::Floor => unsafe {
+                bindings::dev_pm_opp_find_level_floor(rdev, &mut level as *mut u32)
+            },
+        })?;
+
+        // SAFETY: The `ptr` is guaranteed by the C code to be valid.
+        unsafe { OPP::from_ptr_owned(ptr) }
+    }
+
+    /// Finds OPP based on bandwidth.
+    pub fn opp_from_bw(&self, mut bw: u32, index: i32, stype: SearchType) -> Result<ARef<OPP>> {
+        let rdev = self.dev.as_raw();
+
+        let ptr = from_err_ptr(match stype {
+            // The OPP core doesn't support this yet.
+            SearchType::Exact => return Err(EINVAL),
+
+            // SAFETY: The requirements are satisfied by the existence of `Device` and its
+            // safety requirements. The returned ptr will be owned by the new [`OPP`] instance.
+            SearchType::Ceil => unsafe {
+                bindings::dev_pm_opp_find_bw_ceil(rdev, &mut bw as *mut u32, index)
+            },
+
+            // SAFETY: The requirements are satisfied by the existence of `Device` and its
+            // safety requirements. The returned ptr will be owned by the new [`OPP`] instance.
+            SearchType::Floor => unsafe {
+                bindings::dev_pm_opp_find_bw_floor(rdev, &mut bw as *mut u32, index)
+            },
+        })?;
+
+        // SAFETY: The `ptr` is guaranteed by the C code to be valid.
+        unsafe { OPP::from_ptr_owned(ptr) }
+    }
+
+    /// Enable the OPP.
+    pub fn enable_opp(&self, freq: u64) -> Result<()> {
+        // SAFETY: The requirements are satisfied by the existence of `Device` and its safety
+        // requirements.
+        to_result(unsafe { bindings::dev_pm_opp_enable(self.dev.as_raw(), freq) })
+    }
+
+    /// Disable the OPP.
+    pub fn disable_opp(&self, freq: u64) -> Result<()> {
+        // SAFETY: The requirements are satisfied by the existence of `Device` and its safety
+        // requirements.
+        to_result(unsafe { bindings::dev_pm_opp_disable(self.dev.as_raw(), freq) })
+    }
+
+    /// Registers with Energy model.
+    #[cfg(CONFIG_OF)]
+    pub fn of_register_em(&mut self, cpumask: &mut cpumask::Cpumask) -> Result<()> {
+        // SAFETY: The requirements are satisfied by the existence of `Device` and its safety
+        // requirements.
+        to_result(unsafe {
+            bindings::dev_pm_opp_of_register_em(self.dev.as_raw(), cpumask.as_mut_ptr())
+        })?;
+
+        self.em = true;
+        Ok(())
+    }
+
+    // Unregisters with Energy model.
+    #[cfg(CONFIG_OF)]
+    fn of_unregister_em(&self) {
+        // SAFETY: The requirements are satisfied by the existence of `Device` and its safety
+        // requirements. We registered with the EM framework earlier, it is safe to unregister now.
+        unsafe { bindings::em_dev_unregister_perf_domain(self.dev.as_raw()) };
+    }
+}
+
+impl Drop for Table {
+    fn drop(&mut self) {
+        // SAFETY: By the type invariants, we know that `self` owns a reference, so it is safe
+        // to relinquish it now.
+        unsafe { bindings::dev_pm_opp_put_opp_table(self.ptr) };
+
+        #[cfg(CONFIG_OF)]
+        {
+            if self.em {
+                self.of_unregister_em();
+            }
+
+            if self.of {
+                self.remove_of();
+            } else if let Some(cpumask) = &self.cpumask {
+                self.remove_of_cpumask(cpumask);
+            }
+        }
+    }
+}
+
 /// Operating performance point (OPP).
 ///
 /// # Invariants