diff options
| -rw-r--r-- | rust/kernel/opp.rs | 295 |
1 files changed, 293 insertions, 2 deletions
diff --git a/rust/kernel/opp.rs b/rust/kernel/opp.rs index 26a0ecfe046a..5293d878cb55 100644 --- a/rust/kernel/opp.rs +++ b/rust/kernel/opp.rs @@ -12,12 +12,29 @@ use crate::{ clk::Hertz, cpumask::{Cpumask, CpumaskVar}, device::Device, - error::{code::*, from_err_ptr, to_result, Error, Result}, + error::{code::*, from_err_ptr, from_result, to_result, Error, Result, VTABLE_DEFAULT_ERROR}, ffi::c_ulong, + prelude::*, + str::CString, types::{ARef, AlwaysRefCounted, Opaque}, }; -use core::ptr; +use core::{marker::PhantomData, ptr}; + +use macros::vtable; + +/// Creates a null-terminated slice of pointers to [`Cstring`]s. +fn to_c_str_array(names: &[CString]) -> Result<KVec<*const u8>> { + // Allocated a null-terminated vector of pointers. + let mut list = KVec::with_capacity(names.len() + 1, GFP_KERNEL)?; + + for name in names.iter() { + list.push(name.as_ptr() as _, GFP_KERNEL)?; + } + + list.push(ptr::null(), GFP_KERNEL)?; + Ok(list) +} /// The voltage unit. /// @@ -205,6 +222,280 @@ pub enum SearchType { Ceil, } +/// OPP configuration callbacks. +/// +/// Implement this trait to customize OPP clock and regulator setup for your device. +#[vtable] +pub trait ConfigOps { + /// This is typically used to scale clocks when transitioning between OPPs. + #[inline] + fn config_clks(_dev: &Device, _table: &Table, _opp: &OPP, _scaling_down: bool) -> Result { + build_error!(VTABLE_DEFAULT_ERROR) + } + + /// This provides access to the old and new OPPs, allowing for safe regulator adjustments. + #[inline] + fn config_regulators( + _dev: &Device, + _opp_old: &OPP, + _opp_new: &OPP, + _data: *mut *mut bindings::regulator, + _count: u32, + ) -> Result { + build_error!(VTABLE_DEFAULT_ERROR) + } +} + +/// OPP configuration token. +/// +/// Returned by the OPP core when configuration is applied to a [`Device`]. The associated +/// configuration is automatically cleared when the token is dropped. +pub struct ConfigToken(i32); + +impl Drop for ConfigToken { + fn drop(&mut self) { + // SAFETY: This is the same token value returned by the C code via `dev_pm_opp_set_config`. + unsafe { bindings::dev_pm_opp_clear_config(self.0) }; + } +} + +/// OPP configurations. +/// +/// Rust abstraction for the C `struct dev_pm_opp_config`. +/// +/// ## Examples +/// +/// The following example demonstrates how to set OPP property-name configuration for a [`Device`]. +/// +/// ``` +/// use kernel::device::Device; +/// use kernel::error::Result; +/// use kernel::opp::{Config, ConfigOps, ConfigToken}; +/// use kernel::str::CString; +/// use kernel::types::ARef; +/// use kernel::macros::vtable; +/// +/// #[derive(Default)] +/// struct Driver; +/// +/// #[vtable] +/// impl ConfigOps for Driver {} +/// +/// fn configure(dev: &ARef<Device>) -> Result<ConfigToken> { +/// let name = CString::try_from_fmt(fmt!("{}", "slow"))?; +/// +/// // The OPP configuration is cleared once the [`ConfigToken`] goes out of scope. +/// Config::<Driver>::new() +/// .set_prop_name(name)? +/// .set(dev) +/// } +/// ``` +#[derive(Default)] +pub struct Config<T: ConfigOps> +where + T: Default, +{ + clk_names: Option<KVec<CString>>, + prop_name: Option<CString>, + regulator_names: Option<KVec<CString>>, + supported_hw: Option<KVec<u32>>, + + // Tuple containing (required device, index) + required_dev: Option<(ARef<Device>, u32)>, + _data: PhantomData<T>, +} + +impl<T: ConfigOps + Default> Config<T> { + /// Creates a new instance of [`Config`]. + #[inline] + pub fn new() -> Self { + Self::default() + } + + /// Initializes clock names. + pub fn set_clk_names(mut self, names: KVec<CString>) -> Result<Self> { + if self.clk_names.is_some() { + return Err(EBUSY); + } + + if names.is_empty() { + return Err(EINVAL); + } + + self.clk_names = Some(names); + Ok(self) + } + + /// Initializes property name. + pub fn set_prop_name(mut self, name: CString) -> Result<Self> { + if self.prop_name.is_some() { + return Err(EBUSY); + } + + self.prop_name = Some(name); + Ok(self) + } + + /// Initializes regulator names. + pub fn set_regulator_names(mut self, names: KVec<CString>) -> Result<Self> { + if self.regulator_names.is_some() { + return Err(EBUSY); + } + + if names.is_empty() { + return Err(EINVAL); + } + + self.regulator_names = Some(names); + + Ok(self) + } + + /// Initializes required devices. + pub fn set_required_dev(mut self, dev: ARef<Device>, index: u32) -> Result<Self> { + if self.required_dev.is_some() { + return Err(EBUSY); + } + + self.required_dev = Some((dev, index)); + Ok(self) + } + + /// Initializes supported hardware. + pub fn set_supported_hw(mut self, hw: KVec<u32>) -> Result<Self> { + if self.supported_hw.is_some() { + return Err(EBUSY); + } + + if hw.is_empty() { + return Err(EINVAL); + } + + self.supported_hw = Some(hw); + Ok(self) + } + + /// Sets the configuration with the OPP core. + /// + /// The returned [`ConfigToken`] will remove the configuration when dropped. + pub fn set(self, dev: &Device) -> Result<ConfigToken> { + let (_clk_list, clk_names) = match &self.clk_names { + Some(x) => { + let list = to_c_str_array(x)?; + let ptr = list.as_ptr(); + (Some(list), ptr) + } + None => (None, ptr::null()), + }; + + let (_regulator_list, regulator_names) = match &self.regulator_names { + Some(x) => { + let list = to_c_str_array(x)?; + let ptr = list.as_ptr(); + (Some(list), ptr) + } + None => (None, ptr::null()), + }; + + let prop_name = self + .prop_name + .as_ref() + .map_or(ptr::null(), |p| p.as_char_ptr()); + + let (supported_hw, supported_hw_count) = self + .supported_hw + .as_ref() + .map_or((ptr::null(), 0), |hw| (hw.as_ptr(), hw.len() as u32)); + + let (required_dev, required_dev_index) = self + .required_dev + .as_ref() + .map_or((ptr::null_mut(), 0), |(dev, idx)| (dev.as_raw(), *idx)); + + let mut config = bindings::dev_pm_opp_config { + clk_names, + config_clks: if T::HAS_CONFIG_CLKS { + Some(Self::config_clks) + } else { + None + }, + prop_name, + regulator_names, + config_regulators: if T::HAS_CONFIG_REGULATORS { + Some(Self::config_regulators) + } else { + None + }, + supported_hw, + supported_hw_count, + + required_dev, + required_dev_index, + }; + + // SAFETY: The requirements are satisfied by the existence of [`Device`] and its safety + // requirements. The OPP core guarantees not to access fields of [`Config`] after this call + // and so we don't need to save a copy of them for future use. + let ret = unsafe { bindings::dev_pm_opp_set_config(dev.as_raw(), &mut config) }; + if ret < 0 { + Err(Error::from_errno(ret)) + } else { + Ok(ConfigToken(ret)) + } + } + + /// Config's clk callback. + /// + /// SAFETY: Called from C. Inputs must be valid pointers. + extern "C" fn config_clks( + dev: *mut bindings::device, + opp_table: *mut bindings::opp_table, + opp: *mut bindings::dev_pm_opp, + _data: *mut kernel::ffi::c_void, + scaling_down: bool, + ) -> kernel::ffi::c_int { + from_result(|| { + // SAFETY: 'dev' is guaranteed by the C code to be valid. + let dev = unsafe { Device::get_device(dev) }; + T::config_clks( + &dev, + // SAFETY: 'opp_table' is guaranteed by the C code to be valid. + &unsafe { Table::from_raw_table(opp_table, &dev) }, + // SAFETY: 'opp' is guaranteed by the C code to be valid. + unsafe { OPP::from_raw_opp(opp)? }, + scaling_down, + ) + .map(|()| 0) + }) + } + + /// Config's regulator callback. + /// + /// SAFETY: Called from C. Inputs must be valid pointers. + extern "C" fn config_regulators( + dev: *mut bindings::device, + old_opp: *mut bindings::dev_pm_opp, + new_opp: *mut bindings::dev_pm_opp, + regulators: *mut *mut bindings::regulator, + count: kernel::ffi::c_uint, + ) -> kernel::ffi::c_int { + from_result(|| { + // SAFETY: 'dev' is guaranteed by the C code to be valid. + let dev = unsafe { Device::get_device(dev) }; + T::config_regulators( + &dev, + // SAFETY: 'old_opp' is guaranteed by the C code to be valid. + unsafe { OPP::from_raw_opp(old_opp)? }, + // SAFETY: 'new_opp' is guaranteed by the C code to be valid. + unsafe { OPP::from_raw_opp(new_opp)? }, + regulators, + count, + ) + .map(|()| 0) + }) + } +} + /// A reference-counted OPP table. /// /// Rust abstraction for the C `struct opp_table`. |