| Message ID | 0f8618610dde586284d8c9971b8bdf215eef0456.1719990273.git.viresh.kumar@linaro.org (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
| Series | Rust bindings for cpufreq and OPP core + sample driver | expand |
On 7/3/24 09:14, Viresh Kumar wrote: > This extends the cpufreq bindings with bindings for registering a > driver. > > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> > --- > rust/kernel/cpufreq.rs | 482 ++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 479 insertions(+), 3 deletions(-) > > diff --git a/rust/kernel/cpufreq.rs b/rust/kernel/cpufreq.rs > index 6f9d34ebbcb0..66dad18f4ab6 100644 > --- a/rust/kernel/cpufreq.rs > +++ b/rust/kernel/cpufreq.rs > @@ -9,14 +9,16 @@ > use crate::{ > bindings, clk, cpumask, > device::Device, > - error::{code::*, from_err_ptr, to_result, Result, VTABLE_DEFAULT_ERROR}, > + error::{code::*, from_err_ptr, from_result, to_result, Result, VTABLE_DEFAULT_ERROR}, > prelude::*, > - types::{ARef, ForeignOwnable}, > + types::ForeignOwnable, > }; > > use core::{ > + cell::UnsafeCell, > + marker::PhantomData, > pin::Pin, > - ptr::self, > + ptr::{self, addr_of_mut}, > }; > > use macros::vtable; > @@ -563,3 +565,477 @@ fn register_em(_policy: &mut Policy) { > kernel::build_error(VTABLE_DEFAULT_ERROR) > } > } > + > +/// Registration of a cpufreq driver. > +pub struct Registration<T: Driver> { > + registered: bool, > + drv: UnsafeCell<bindings::cpufreq_driver>, > + _p: PhantomData<T>, > +} > + > +// SAFETY: `Registration` doesn't offer any methods or access to fields when shared between threads > +// or CPUs, so it is safe to share it. > +unsafe impl<T: Driver> Sync for Registration<T> {} > + > +// SAFETY: Registration with and unregistration from the cpufreq subsystem can happen from any thread. > +// Additionally, `T::Data` (which is dropped during unregistration) is `Send`, so it is okay to move > +// `Registration` to different threads. > +#[allow(clippy::non_send_fields_in_send_ty)] > +unsafe impl<T: Driver> Send for Registration<T> {} > + > +impl<T: Driver> Registration<T> { > + /// Creates new [`Registration`] but does not register it yet. > + /// > + /// It is allowed to move. > + fn new() -> Result<Box<Self>> { > + Ok(Box::new( > + Self { > + registered: false, > + drv: UnsafeCell::new(bindings::cpufreq_driver::default()), > + _p: PhantomData, > + }, > + GFP_KERNEL, > + )?) > + } > + > + /// Registers a cpufreq driver with the rest of the kernel. > + pub fn register( > + name: &'static CStr, > + data: T::Data, > + flags: u16, > + boost: bool, > + ) -> Result<Box<Self>> { If you directly call `register` from `new` you can avoid having `Self::registered`. It's also a bit cleaner, once you got an instance of `Registration` it means something is registered, once it's dropped, it's unregistered. > + let mut reg = Self::new()?; > + let drv = reg.drv.get_mut(); > + > + // Account for the trailing null character. > + let len = name.len() + 1; > + if len > drv.name.len() { > + return Err(EINVAL); > + }; > + > + // SAFETY: `name` is a valid Cstr, and we are copying it to an array of equal or larger > + // size. > + let name = unsafe { &*(name.as_bytes_with_nul() as *const [u8] as *const [i8]) }; > + drv.name[..len].copy_from_slice(name); > + > + drv.boost_enabled = boost; > + drv.flags = flags; > + > + // Allocate an array of 3 pointers to be passed to the C code. > + let mut attr = Box::new([ptr::null_mut(); 3], GFP_KERNEL)?; > + let mut next = 0; > + > + // SAFETY: The C code returns a valid pointer here, which is again passed to the C code in > + // an array. > + attr[next] = > + unsafe { addr_of_mut!(bindings::cpufreq_freq_attr_scaling_available_freqs) as *mut _ }; > + next += 1; > + > + if boost { > + // SAFETY: The C code returns a valid pointer here, which is again passed to the C code > + // in an array. > + attr[next] = > + unsafe { addr_of_mut!(bindings::cpufreq_freq_attr_scaling_boost_freqs) as *mut _ }; > + next += 1; > + } > + attr[next] = ptr::null_mut(); > + > + // Pass the ownership of the memory block to the C code. This will be freed when > + // the [`Registration`] object goes out of scope. > + drv.attr = Box::leak(attr) as *mut _; > + > + // Initialize mandatory callbacks. > + drv.init = Some(Self::init_callback); > + drv.verify = Some(Self::verify_callback); > + > + // Initialize optional callbacks. > + drv.setpolicy = if T::HAS_SETPOLICY { > + Some(Self::setpolicy_callback) > + } else { > + None > + }; > + drv.target = if T::HAS_TARGET { > + Some(Self::target_callback) > + } else { > + None > + }; > + drv.target_index = if T::HAS_TARGET_INDEX { > + Some(Self::target_index_callback) > + } else { > + None > + }; > + drv.fast_switch = if T::HAS_FAST_SWITCH { > + Some(Self::fast_switch_callback) > + } else { > + None > + }; > + drv.adjust_perf = if T::HAS_ADJUST_PERF { > + Some(Self::adjust_perf_callback) > + } else { > + None > + }; > + drv.get_intermediate = if T::HAS_GET_INTERMEDIATE { > + Some(Self::get_intermediate_callback) > + } else { > + None > + }; > + drv.target_intermediate = if T::HAS_TARGET_INTERMEDIATE { > + Some(Self::target_intermediate_callback) > + } else { > + None > + }; > + drv.get = if T::HAS_GET { > + Some(Self::get_callback) > + } else { > + None > + }; > + drv.update_limits = if T::HAS_UPDATE_LIMITS { > + Some(Self::update_limits_callback) > + } else { > + None > + }; > + drv.bios_limit = if T::HAS_BIOS_LIMIT { > + Some(Self::bios_limit_callback) > + } else { > + None > + }; > + drv.online = if T::HAS_ONLINE { > + Some(Self::online_callback) > + } else { > + None > + }; > + drv.offline = if T::HAS_OFFLINE { > + Some(Self::offline_callback) > + } else { > + None > + }; > + drv.exit = if T::HAS_EXIT { > + Some(Self::exit_callback) > + } else { > + None > + }; > + drv.suspend = if T::HAS_SUSPEND { > + Some(Self::suspend_callback) > + } else { > + None > + }; > + drv.resume = if T::HAS_RESUME { > + Some(Self::resume_callback) > + } else { > + None > + }; > + drv.ready = if T::HAS_READY { > + Some(Self::ready_callback) > + } else { > + None > + }; > + drv.set_boost = if T::HAS_SET_BOOST { > + Some(Self::set_boost_callback) > + } else { > + None > + }; > + drv.register_em = if T::HAS_REGISTER_EM { > + Some(Self::register_em_callback) > + } else { > + None > + }; > + > + // Set driver data before registering the driver, as the cpufreq core may call few > + // callbacks before `cpufreq_register_driver()` returns. > + reg.set_data(data)?; > + > + // SAFETY: It is safe to register the driver with the cpufreq core in the C code. > + to_result(unsafe { bindings::cpufreq_register_driver(reg.drv.get()) })?; > + reg.registered = true; > + Ok(reg) > + } > + > + /// Returns the previous set data for a cpufreq driver. > + pub fn data<D: ForeignOwnable>() -> Option<<D>::Borrowed<'static>> { > + // SAFETY: The driver data is earlier set by us from [`set_data()`]. > + let data = unsafe { bindings::cpufreq_get_driver_data() }; > + if data.is_null() { > + None > + } else { > + // SAFETY: The driver data is earlier set by us from [`set_data()`]. > + Some(unsafe { D::borrow(data) }) > + } > + } > + > + // Sets the data for a cpufreq driver. > + fn set_data(&mut self, data: T::Data) -> Result<()> { > + let drv = self.drv.get_mut(); > + > + if drv.driver_data.is_null() { > + // Pass the ownership of the data to the foreign interface. > + drv.driver_data = <T::Data as ForeignOwnable>::into_foreign(data) as _; > + Ok(()) > + } else { > + Err(EBUSY) > + } > + } > + > + // Clears and returns the data for a cpufreq driver. > + fn clear_data(&mut self) -> Option<T::Data> { > + let drv = self.drv.get_mut(); > + > + if drv.driver_data.is_null() { > + None > + } else { > + // SAFETY: By the type invariants, we know that `self` owns a reference, so it is safe to > + // relinquish it now. > + let data = Some(unsafe { <T::Data as ForeignOwnable>::from_foreign(drv.driver_data) }); > + drv.driver_data = ptr::null_mut(); > + data > + } > + } > +} > + > +// cpufreq driver callbacks. > +impl<T: Driver> Registration<T> { > + // Policy's init callback. > + extern "C" fn init_callback(ptr: *mut bindings::cpufreq_policy) -> core::ffi::c_int { > + from_result(|| { > + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the > + // duration of this call, so it is guaranteed to remain alive for the lifetime of > + // `ptr`. > + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; > + > + let data = T::init(&mut policy)?; > + policy.set_data(data)?; > + Ok(0) > + }) > + } > + > + // Policy's exit callback. > + extern "C" fn exit_callback(ptr: *mut bindings::cpufreq_policy) -> core::ffi::c_int { > + from_result(|| { > + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the > + // duration of this call, so it is guaranteed to remain alive for the lifetime of > + // `ptr`. > + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; > + > + let data = policy.clear_data(); > + T::exit(&mut policy, data).map(|_| 0) > + }) > + } > + > + // Policy's online callback. > + extern "C" fn online_callback(ptr: *mut bindings::cpufreq_policy) -> core::ffi::c_int { > + from_result(|| { > + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the > + // duration of this call, so it is guaranteed to remain alive for the lifetime of > + // `ptr`. > + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; > + T::online(&mut policy).map(|_| 0) > + }) > + } > + > + // Policy's offline callback. > + extern "C" fn offline_callback(ptr: *mut bindings::cpufreq_policy) -> core::ffi::c_int { > + from_result(|| { > + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the > + // duration of this call, so it is guaranteed to remain alive for the lifetime of > + // `ptr`. > + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; > + T::offline(&mut policy).map(|_| 0) > + }) > + } > + > + // Policy's suspend callback. > + extern "C" fn suspend_callback(ptr: *mut bindings::cpufreq_policy) -> core::ffi::c_int { > + from_result(|| { > + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the > + // duration of this call, so it is guaranteed to remain alive for the lifetime of > + // `ptr`. > + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; > + T::suspend(&mut policy).map(|_| 0) > + }) > + } > + > + // Policy's resume callback. > + extern "C" fn resume_callback(ptr: *mut bindings::cpufreq_policy) -> core::ffi::c_int { > + from_result(|| { > + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the > + // duration of this call, so it is guaranteed to remain alive for the lifetime of > + // `ptr`. > + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; > + T::resume(&mut policy).map(|_| 0) > + }) > + } > + > + // Policy's ready callback. > + extern "C" fn ready_callback(ptr: *mut bindings::cpufreq_policy) { > + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the > + // duration of this call, so it is guaranteed to remain alive for the lifetime of > + // `ptr`. > + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; > + T::ready(&mut policy); > + } > + > + // Policy's verify callback. > + extern "C" fn verify_callback(ptr: *mut bindings::cpufreq_policy_data) -> core::ffi::c_int { > + from_result(|| { > + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the > + // duration of this call, so it is guaranteed to remain alive for the lifetime of > + // `ptr`. > + let mut data = unsafe { PolicyData::from_raw_policy_data(ptr) }; > + T::verify(&mut data).map(|_| 0) > + }) > + } > + > + // Policy's setpolicy callback. > + extern "C" fn setpolicy_callback(ptr: *mut bindings::cpufreq_policy) -> core::ffi::c_int { > + from_result(|| { > + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the > + // duration of this call, so it is guaranteed to remain alive for the lifetime of > + // `ptr`. > + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; > + T::setpolicy(&mut policy).map(|_| 0) > + }) > + } > + > + // Policy's target callback. > + extern "C" fn target_callback( > + ptr: *mut bindings::cpufreq_policy, > + target_freq: u32, > + relation: u32, > + ) -> core::ffi::c_int { > + from_result(|| { > + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the > + // duration of this call, so it is guaranteed to remain alive for the lifetime of > + // `ptr`. > + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; > + T::target(&mut policy, target_freq, Relation::new(relation)?).map(|_| 0) > + }) > + } > + > + // Policy's target_index callback. > + extern "C" fn target_index_callback( > + ptr: *mut bindings::cpufreq_policy, > + index: u32, > + ) -> core::ffi::c_int { > + from_result(|| { > + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the > + // duration of this call, so it is guaranteed to remain alive for the lifetime of > + // `ptr`. > + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; > + T::target_index(&mut policy, index).map(|_| 0) > + }) > + } > + > + // Policy's fast_switch callback. > + extern "C" fn fast_switch_callback( > + ptr: *mut bindings::cpufreq_policy, > + target_freq: u32, > + ) -> core::ffi::c_uint { > + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the > + // duration of this call, so it is guaranteed to remain alive for the lifetime of > + // `ptr`. > + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; > + T::fast_switch(&mut policy, target_freq) > + } > + > + // Policy's adjust_perf callback. > + extern "C" fn adjust_perf_callback(cpu: u32, min_perf: u64, target_perf: u64, capacity: u64) { > + if let Ok(mut policy) = Policy::from_cpu(cpu) { > + T::adjust_perf(&mut policy, min_perf, target_perf, capacity); > + } > + } > + > + // Policy's get_intermediate callback. > + extern "C" fn get_intermediate_callback( > + ptr: *mut bindings::cpufreq_policy, > + index: u32, > + ) -> core::ffi::c_uint { > + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the > + // duration of this call, so it is guaranteed to remain alive for the lifetime of > + // `ptr`. > + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; > + T::get_intermediate(&mut policy, index) > + } > + > + // Policy's target_intermediate callback. > + extern "C" fn target_intermediate_callback( > + ptr: *mut bindings::cpufreq_policy, > + index: u32, > + ) -> core::ffi::c_int { > + from_result(|| { > + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the > + // duration of this call, so it is guaranteed to remain alive for the lifetime of > + // `ptr`. > + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; > + T::target_intermediate(&mut policy, index).map(|_| 0) > + }) > + } > + > + // Policy's get callback. > + extern "C" fn get_callback(cpu: u32) -> core::ffi::c_uint { > + // SAFETY: Get the policy for a CPU. > + Policy::from_cpu(cpu).map_or(0, |mut policy| T::get(&mut policy).map_or(0, |f| f)) > + } > + > + // Policy's update_limit callback. > + extern "C" fn update_limits_callback(cpu: u32) { > + // SAFETY: Get the policy for a CPU. > + if let Ok(mut policy) = Policy::from_cpu(cpu) { > + T::update_limits(&mut policy); > + } > + } > + > + // Policy's bios_limit callback. > + extern "C" fn bios_limit_callback(cpu: i32, limit: *mut u32) -> core::ffi::c_int { > + from_result(|| { > + let mut policy = Policy::from_cpu(cpu as u32)?; > + > + // SAFETY: The pointer is guaranteed by the C code to be valid. > + T::bios_limit(&mut policy, &mut (unsafe { *limit })).map(|_| 0) > + }) > + } > + > + // Policy's set_boost callback. > + extern "C" fn set_boost_callback( > + ptr: *mut bindings::cpufreq_policy, > + state: i32, > + ) -> core::ffi::c_int { > + from_result(|| { > + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the > + // duration of this call, so it is guaranteed to remain alive for the lifetime of > + // `ptr`. > + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; > + T::set_boost(&mut policy, state).map(|_| 0) > + }) > + } > + > + // Policy's register_em callback. > + extern "C" fn register_em_callback(ptr: *mut bindings::cpufreq_policy) { > + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the > + // duration of this call, so it is guaranteed to remain alive for the lifetime of > + // `ptr`. > + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; > + T::register_em(&mut policy); > + } > +} > + > +impl<T: Driver> Drop for Registration<T> { > + // Removes the registration from the kernel if it has completed successfully before. > + fn drop(&mut self) { > + pr_info!("Registration dropped\n"); > + let drv = self.drv.get_mut(); > + > + if self.registered { > + // SAFETY: The driver was earlier registered from `register()`. > + unsafe { bindings::cpufreq_unregister_driver(drv) }; > + } > + > + // Free the previously leaked memory to the C code. > + if !drv.attr.is_null() { > + // SAFETY: The pointer was earlier initialized from the result of `Box::leak`. > + unsafe { drop(Box::from_raw(drv.attr)) }; > + } > + > + // Free data > + drop(self.clear_data()); > + } > +}
On 7/5/24 13:39, Danilo Krummrich wrote: > On 7/3/24 09:14, Viresh Kumar wrote: >> This extends the cpufreq bindings with bindings for registering a >> driver. >> >> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> >> --- >> rust/kernel/cpufreq.rs | 482 ++++++++++++++++++++++++++++++++++++++++- >> 1 file changed, 479 insertions(+), 3 deletions(-) >> >> diff --git a/rust/kernel/cpufreq.rs b/rust/kernel/cpufreq.rs >> index 6f9d34ebbcb0..66dad18f4ab6 100644 >> --- a/rust/kernel/cpufreq.rs >> +++ b/rust/kernel/cpufreq.rs >> @@ -9,14 +9,16 @@ >> use crate::{ >> bindings, clk, cpumask, >> device::Device, >> - error::{code::*, from_err_ptr, to_result, Result, VTABLE_DEFAULT_ERROR}, >> + error::{code::*, from_err_ptr, from_result, to_result, Result, VTABLE_DEFAULT_ERROR}, >> prelude::*, >> - types::{ARef, ForeignOwnable}, >> + types::ForeignOwnable, >> }; >> use core::{ >> + cell::UnsafeCell, >> + marker::PhantomData, >> pin::Pin, >> - ptr::self, >> + ptr::{self, addr_of_mut}, >> }; >> use macros::vtable; >> @@ -563,3 +565,477 @@ fn register_em(_policy: &mut Policy) { >> kernel::build_error(VTABLE_DEFAULT_ERROR) >> } >> } >> + >> +/// Registration of a cpufreq driver. >> +pub struct Registration<T: Driver> { >> + registered: bool, >> + drv: UnsafeCell<bindings::cpufreq_driver>, >> + _p: PhantomData<T>, >> +} >> + >> +// SAFETY: `Registration` doesn't offer any methods or access to fields when shared between threads >> +// or CPUs, so it is safe to share it. >> +unsafe impl<T: Driver> Sync for Registration<T> {} >> + >> +// SAFETY: Registration with and unregistration from the cpufreq subsystem can happen from any thread. >> +// Additionally, `T::Data` (which is dropped during unregistration) is `Send`, so it is okay to move >> +// `Registration` to different threads. >> +#[allow(clippy::non_send_fields_in_send_ty)] >> +unsafe impl<T: Driver> Send for Registration<T> {} >> + >> +impl<T: Driver> Registration<T> { >> + /// Creates new [`Registration`] but does not register it yet. >> + /// >> + /// It is allowed to move. >> + fn new() -> Result<Box<Self>> { >> + Ok(Box::new( >> + Self { >> + registered: false, >> + drv: UnsafeCell::new(bindings::cpufreq_driver::default()), >> + _p: PhantomData, >> + }, >> + GFP_KERNEL, >> + )?) >> + } >> + >> + /// Registers a cpufreq driver with the rest of the kernel. >> + pub fn register( >> + name: &'static CStr, >> + data: T::Data, >> + flags: u16, >> + boost: bool, >> + ) -> Result<Box<Self>> { > > If you directly call `register` from `new` you can avoid having `Self::registered`. > It's also a bit cleaner, once you got an instance of `Registration` it means something > is registered, once it's dropped, it's unregistered. Nevermind, I didn't notice `new` is private and you actually already do that. However, this means you can drop `Self::registered`. > >> + let mut reg = Self::new()?; >> + let drv = reg.drv.get_mut(); >> + >> + // Account for the trailing null character. >> + let len = name.len() + 1; >> + if len > drv.name.len() { >> + return Err(EINVAL); >> + }; >> + >> + // SAFETY: `name` is a valid Cstr, and we are copying it to an array of equal or larger >> + // size. >> + let name = unsafe { &*(name.as_bytes_with_nul() as *const [u8] as *const [i8]) }; >> + drv.name[..len].copy_from_slice(name); >> + >> + drv.boost_enabled = boost; >> + drv.flags = flags; >> + >> + // Allocate an array of 3 pointers to be passed to the C code. >> + let mut attr = Box::new([ptr::null_mut(); 3], GFP_KERNEL)?; >> + let mut next = 0; >> + >> + // SAFETY: The C code returns a valid pointer here, which is again passed to the C code in >> + // an array. >> + attr[next] = >> + unsafe { addr_of_mut!(bindings::cpufreq_freq_attr_scaling_available_freqs) as *mut _ }; >> + next += 1; >> + >> + if boost { >> + // SAFETY: The C code returns a valid pointer here, which is again passed to the C code >> + // in an array. >> + attr[next] = >> + unsafe { addr_of_mut!(bindings::cpufreq_freq_attr_scaling_boost_freqs) as *mut _ }; >> + next += 1; >> + } >> + attr[next] = ptr::null_mut(); >> + >> + // Pass the ownership of the memory block to the C code. This will be freed when >> + // the [`Registration`] object goes out of scope. >> + drv.attr = Box::leak(attr) as *mut _; >> + >> + // Initialize mandatory callbacks. >> + drv.init = Some(Self::init_callback); >> + drv.verify = Some(Self::verify_callback); >> + >> + // Initialize optional callbacks. >> + drv.setpolicy = if T::HAS_SETPOLICY { >> + Some(Self::setpolicy_callback) >> + } else { >> + None >> + }; >> + drv.target = if T::HAS_TARGET { >> + Some(Self::target_callback) >> + } else { >> + None >> + }; >> + drv.target_index = if T::HAS_TARGET_INDEX { >> + Some(Self::target_index_callback) >> + } else { >> + None >> + }; >> + drv.fast_switch = if T::HAS_FAST_SWITCH { >> + Some(Self::fast_switch_callback) >> + } else { >> + None >> + }; >> + drv.adjust_perf = if T::HAS_ADJUST_PERF { >> + Some(Self::adjust_perf_callback) >> + } else { >> + None >> + }; >> + drv.get_intermediate = if T::HAS_GET_INTERMEDIATE { >> + Some(Self::get_intermediate_callback) >> + } else { >> + None >> + }; >> + drv.target_intermediate = if T::HAS_TARGET_INTERMEDIATE { >> + Some(Self::target_intermediate_callback) >> + } else { >> + None >> + }; >> + drv.get = if T::HAS_GET { >> + Some(Self::get_callback) >> + } else { >> + None >> + }; >> + drv.update_limits = if T::HAS_UPDATE_LIMITS { >> + Some(Self::update_limits_callback) >> + } else { >> + None >> + }; >> + drv.bios_limit = if T::HAS_BIOS_LIMIT { >> + Some(Self::bios_limit_callback) >> + } else { >> + None >> + }; >> + drv.online = if T::HAS_ONLINE { >> + Some(Self::online_callback) >> + } else { >> + None >> + }; >> + drv.offline = if T::HAS_OFFLINE { >> + Some(Self::offline_callback) >> + } else { >> + None >> + }; >> + drv.exit = if T::HAS_EXIT { >> + Some(Self::exit_callback) >> + } else { >> + None >> + }; >> + drv.suspend = if T::HAS_SUSPEND { >> + Some(Self::suspend_callback) >> + } else { >> + None >> + }; >> + drv.resume = if T::HAS_RESUME { >> + Some(Self::resume_callback) >> + } else { >> + None >> + }; >> + drv.ready = if T::HAS_READY { >> + Some(Self::ready_callback) >> + } else { >> + None >> + }; >> + drv.set_boost = if T::HAS_SET_BOOST { >> + Some(Self::set_boost_callback) >> + } else { >> + None >> + }; >> + drv.register_em = if T::HAS_REGISTER_EM { >> + Some(Self::register_em_callback) >> + } else { >> + None >> + }; >> + >> + // Set driver data before registering the driver, as the cpufreq core may call few >> + // callbacks before `cpufreq_register_driver()` returns. >> + reg.set_data(data)?; >> + >> + // SAFETY: It is safe to register the driver with the cpufreq core in the C code. >> + to_result(unsafe { bindings::cpufreq_register_driver(reg.drv.get()) })?; >> + reg.registered = true; >> + Ok(reg) >> + } >> + >> + /// Returns the previous set data for a cpufreq driver. >> + pub fn data<D: ForeignOwnable>() -> Option<<D>::Borrowed<'static>> { >> + // SAFETY: The driver data is earlier set by us from [`set_data()`]. >> + let data = unsafe { bindings::cpufreq_get_driver_data() }; >> + if data.is_null() { >> + None >> + } else { >> + // SAFETY: The driver data is earlier set by us from [`set_data()`]. >> + Some(unsafe { D::borrow(data) }) >> + } >> + } >> + >> + // Sets the data for a cpufreq driver. >> + fn set_data(&mut self, data: T::Data) -> Result<()> { >> + let drv = self.drv.get_mut(); >> + >> + if drv.driver_data.is_null() { >> + // Pass the ownership of the data to the foreign interface. >> + drv.driver_data = <T::Data as ForeignOwnable>::into_foreign(data) as _; >> + Ok(()) >> + } else { >> + Err(EBUSY) >> + } >> + } >> + >> + // Clears and returns the data for a cpufreq driver. >> + fn clear_data(&mut self) -> Option<T::Data> { >> + let drv = self.drv.get_mut(); >> + >> + if drv.driver_data.is_null() { >> + None >> + } else { >> + // SAFETY: By the type invariants, we know that `self` owns a reference, so it is safe to >> + // relinquish it now. >> + let data = Some(unsafe { <T::Data as ForeignOwnable>::from_foreign(drv.driver_data) }); >> + drv.driver_data = ptr::null_mut(); >> + data >> + } >> + } >> +} >> + >> +// cpufreq driver callbacks. >> +impl<T: Driver> Registration<T> { >> + // Policy's init callback. >> + extern "C" fn init_callback(ptr: *mut bindings::cpufreq_policy) -> core::ffi::c_int { >> + from_result(|| { >> + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the >> + // duration of this call, so it is guaranteed to remain alive for the lifetime of >> + // `ptr`. >> + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; >> + >> + let data = T::init(&mut policy)?; >> + policy.set_data(data)?; >> + Ok(0) >> + }) >> + } >> + >> + // Policy's exit callback. >> + extern "C" fn exit_callback(ptr: *mut bindings::cpufreq_policy) -> core::ffi::c_int { >> + from_result(|| { >> + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the >> + // duration of this call, so it is guaranteed to remain alive for the lifetime of >> + // `ptr`. >> + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; >> + >> + let data = policy.clear_data(); >> + T::exit(&mut policy, data).map(|_| 0) >> + }) >> + } >> + >> + // Policy's online callback. >> + extern "C" fn online_callback(ptr: *mut bindings::cpufreq_policy) -> core::ffi::c_int { >> + from_result(|| { >> + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the >> + // duration of this call, so it is guaranteed to remain alive for the lifetime of >> + // `ptr`. >> + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; >> + T::online(&mut policy).map(|_| 0) >> + }) >> + } >> + >> + // Policy's offline callback. >> + extern "C" fn offline_callback(ptr: *mut bindings::cpufreq_policy) -> core::ffi::c_int { >> + from_result(|| { >> + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the >> + // duration of this call, so it is guaranteed to remain alive for the lifetime of >> + // `ptr`. >> + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; >> + T::offline(&mut policy).map(|_| 0) >> + }) >> + } >> + >> + // Policy's suspend callback. >> + extern "C" fn suspend_callback(ptr: *mut bindings::cpufreq_policy) -> core::ffi::c_int { >> + from_result(|| { >> + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the >> + // duration of this call, so it is guaranteed to remain alive for the lifetime of >> + // `ptr`. >> + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; >> + T::suspend(&mut policy).map(|_| 0) >> + }) >> + } >> + >> + // Policy's resume callback. >> + extern "C" fn resume_callback(ptr: *mut bindings::cpufreq_policy) -> core::ffi::c_int { >> + from_result(|| { >> + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the >> + // duration of this call, so it is guaranteed to remain alive for the lifetime of >> + // `ptr`. >> + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; >> + T::resume(&mut policy).map(|_| 0) >> + }) >> + } >> + >> + // Policy's ready callback. >> + extern "C" fn ready_callback(ptr: *mut bindings::cpufreq_policy) { >> + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the >> + // duration of this call, so it is guaranteed to remain alive for the lifetime of >> + // `ptr`. >> + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; >> + T::ready(&mut policy); >> + } >> + >> + // Policy's verify callback. >> + extern "C" fn verify_callback(ptr: *mut bindings::cpufreq_policy_data) -> core::ffi::c_int { >> + from_result(|| { >> + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the >> + // duration of this call, so it is guaranteed to remain alive for the lifetime of >> + // `ptr`. >> + let mut data = unsafe { PolicyData::from_raw_policy_data(ptr) }; >> + T::verify(&mut data).map(|_| 0) >> + }) >> + } >> + >> + // Policy's setpolicy callback. >> + extern "C" fn setpolicy_callback(ptr: *mut bindings::cpufreq_policy) -> core::ffi::c_int { >> + from_result(|| { >> + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the >> + // duration of this call, so it is guaranteed to remain alive for the lifetime of >> + // `ptr`. >> + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; >> + T::setpolicy(&mut policy).map(|_| 0) >> + }) >> + } >> + >> + // Policy's target callback. >> + extern "C" fn target_callback( >> + ptr: *mut bindings::cpufreq_policy, >> + target_freq: u32, >> + relation: u32, >> + ) -> core::ffi::c_int { >> + from_result(|| { >> + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the >> + // duration of this call, so it is guaranteed to remain alive for the lifetime of >> + // `ptr`. >> + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; >> + T::target(&mut policy, target_freq, Relation::new(relation)?).map(|_| 0) >> + }) >> + } >> + >> + // Policy's target_index callback. >> + extern "C" fn target_index_callback( >> + ptr: *mut bindings::cpufreq_policy, >> + index: u32, >> + ) -> core::ffi::c_int { >> + from_result(|| { >> + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the >> + // duration of this call, so it is guaranteed to remain alive for the lifetime of >> + // `ptr`. >> + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; >> + T::target_index(&mut policy, index).map(|_| 0) >> + }) >> + } >> + >> + // Policy's fast_switch callback. >> + extern "C" fn fast_switch_callback( >> + ptr: *mut bindings::cpufreq_policy, >> + target_freq: u32, >> + ) -> core::ffi::c_uint { >> + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the >> + // duration of this call, so it is guaranteed to remain alive for the lifetime of >> + // `ptr`. >> + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; >> + T::fast_switch(&mut policy, target_freq) >> + } >> + >> + // Policy's adjust_perf callback. >> + extern "C" fn adjust_perf_callback(cpu: u32, min_perf: u64, target_perf: u64, capacity: u64) { >> + if let Ok(mut policy) = Policy::from_cpu(cpu) { >> + T::adjust_perf(&mut policy, min_perf, target_perf, capacity); >> + } >> + } >> + >> + // Policy's get_intermediate callback. >> + extern "C" fn get_intermediate_callback( >> + ptr: *mut bindings::cpufreq_policy, >> + index: u32, >> + ) -> core::ffi::c_uint { >> + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the >> + // duration of this call, so it is guaranteed to remain alive for the lifetime of >> + // `ptr`. >> + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; >> + T::get_intermediate(&mut policy, index) >> + } >> + >> + // Policy's target_intermediate callback. >> + extern "C" fn target_intermediate_callback( >> + ptr: *mut bindings::cpufreq_policy, >> + index: u32, >> + ) -> core::ffi::c_int { >> + from_result(|| { >> + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the >> + // duration of this call, so it is guaranteed to remain alive for the lifetime of >> + // `ptr`. >> + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; >> + T::target_intermediate(&mut policy, index).map(|_| 0) >> + }) >> + } >> + >> + // Policy's get callback. >> + extern "C" fn get_callback(cpu: u32) -> core::ffi::c_uint { >> + // SAFETY: Get the policy for a CPU. >> + Policy::from_cpu(cpu).map_or(0, |mut policy| T::get(&mut policy).map_or(0, |f| f)) >> + } >> + >> + // Policy's update_limit callback. >> + extern "C" fn update_limits_callback(cpu: u32) { >> + // SAFETY: Get the policy for a CPU. >> + if let Ok(mut policy) = Policy::from_cpu(cpu) { >> + T::update_limits(&mut policy); >> + } >> + } >> + >> + // Policy's bios_limit callback. >> + extern "C" fn bios_limit_callback(cpu: i32, limit: *mut u32) -> core::ffi::c_int { >> + from_result(|| { >> + let mut policy = Policy::from_cpu(cpu as u32)?; >> + >> + // SAFETY: The pointer is guaranteed by the C code to be valid. >> + T::bios_limit(&mut policy, &mut (unsafe { *limit })).map(|_| 0) >> + }) >> + } >> + >> + // Policy's set_boost callback. >> + extern "C" fn set_boost_callback( >> + ptr: *mut bindings::cpufreq_policy, >> + state: i32, >> + ) -> core::ffi::c_int { >> + from_result(|| { >> + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the >> + // duration of this call, so it is guaranteed to remain alive for the lifetime of >> + // `ptr`. >> + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; >> + T::set_boost(&mut policy, state).map(|_| 0) >> + }) >> + } >> + >> + // Policy's register_em callback. >> + extern "C" fn register_em_callback(ptr: *mut bindings::cpufreq_policy) { >> + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the >> + // duration of this call, so it is guaranteed to remain alive for the lifetime of >> + // `ptr`. >> + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; >> + T::register_em(&mut policy); >> + } >> +} >> + >> +impl<T: Driver> Drop for Registration<T> { >> + // Removes the registration from the kernel if it has completed successfully before. >> + fn drop(&mut self) { >> + pr_info!("Registration dropped\n"); >> + let drv = self.drv.get_mut(); >> + >> + if self.registered { >> + // SAFETY: The driver was earlier registered from `register()`. >> + unsafe { bindings::cpufreq_unregister_driver(drv) }; >> + } >> + >> + // Free the previously leaked memory to the C code. >> + if !drv.attr.is_null() { >> + // SAFETY: The pointer was earlier initialized from the result of `Box::leak`. >> + unsafe { drop(Box::from_raw(drv.attr)) }; >> + } >> + >> + // Free data >> + drop(self.clear_data()); >> + } >> +}
diff --git a/rust/kernel/cpufreq.rs b/rust/kernel/cpufreq.rs index 6f9d34ebbcb0..66dad18f4ab6 100644 --- a/rust/kernel/cpufreq.rs +++ b/rust/kernel/cpufreq.rs @@ -9,14 +9,16 @@ use crate::{ bindings, clk, cpumask, device::Device, - error::{code::*, from_err_ptr, to_result, Result, VTABLE_DEFAULT_ERROR}, + error::{code::*, from_err_ptr, from_result, to_result, Result, VTABLE_DEFAULT_ERROR}, prelude::*, - types::{ARef, ForeignOwnable}, + types::ForeignOwnable, }; use core::{ + cell::UnsafeCell, + marker::PhantomData, pin::Pin, - ptr::self, + ptr::{self, addr_of_mut}, }; use macros::vtable; @@ -563,3 +565,477 @@ fn register_em(_policy: &mut Policy) { kernel::build_error(VTABLE_DEFAULT_ERROR) } } + +/// Registration of a cpufreq driver. +pub struct Registration<T: Driver> { + registered: bool, + drv: UnsafeCell<bindings::cpufreq_driver>, + _p: PhantomData<T>, +} + +// SAFETY: `Registration` doesn't offer any methods or access to fields when shared between threads +// or CPUs, so it is safe to share it. +unsafe impl<T: Driver> Sync for Registration<T> {} + +// SAFETY: Registration with and unregistration from the cpufreq subsystem can happen from any thread. +// Additionally, `T::Data` (which is dropped during unregistration) is `Send`, so it is okay to move +// `Registration` to different threads. +#[allow(clippy::non_send_fields_in_send_ty)] +unsafe impl<T: Driver> Send for Registration<T> {} + +impl<T: Driver> Registration<T> { + /// Creates new [`Registration`] but does not register it yet. + /// + /// It is allowed to move. + fn new() -> Result<Box<Self>> { + Ok(Box::new( + Self { + registered: false, + drv: UnsafeCell::new(bindings::cpufreq_driver::default()), + _p: PhantomData, + }, + GFP_KERNEL, + )?) + } + + /// Registers a cpufreq driver with the rest of the kernel. + pub fn register( + name: &'static CStr, + data: T::Data, + flags: u16, + boost: bool, + ) -> Result<Box<Self>> { + let mut reg = Self::new()?; + let drv = reg.drv.get_mut(); + + // Account for the trailing null character. + let len = name.len() + 1; + if len > drv.name.len() { + return Err(EINVAL); + }; + + // SAFETY: `name` is a valid Cstr, and we are copying it to an array of equal or larger + // size. + let name = unsafe { &*(name.as_bytes_with_nul() as *const [u8] as *const [i8]) }; + drv.name[..len].copy_from_slice(name); + + drv.boost_enabled = boost; + drv.flags = flags; + + // Allocate an array of 3 pointers to be passed to the C code. + let mut attr = Box::new([ptr::null_mut(); 3], GFP_KERNEL)?; + let mut next = 0; + + // SAFETY: The C code returns a valid pointer here, which is again passed to the C code in + // an array. + attr[next] = + unsafe { addr_of_mut!(bindings::cpufreq_freq_attr_scaling_available_freqs) as *mut _ }; + next += 1; + + if boost { + // SAFETY: The C code returns a valid pointer here, which is again passed to the C code + // in an array. + attr[next] = + unsafe { addr_of_mut!(bindings::cpufreq_freq_attr_scaling_boost_freqs) as *mut _ }; + next += 1; + } + attr[next] = ptr::null_mut(); + + // Pass the ownership of the memory block to the C code. This will be freed when + // the [`Registration`] object goes out of scope. + drv.attr = Box::leak(attr) as *mut _; + + // Initialize mandatory callbacks. + drv.init = Some(Self::init_callback); + drv.verify = Some(Self::verify_callback); + + // Initialize optional callbacks. + drv.setpolicy = if T::HAS_SETPOLICY { + Some(Self::setpolicy_callback) + } else { + None + }; + drv.target = if T::HAS_TARGET { + Some(Self::target_callback) + } else { + None + }; + drv.target_index = if T::HAS_TARGET_INDEX { + Some(Self::target_index_callback) + } else { + None + }; + drv.fast_switch = if T::HAS_FAST_SWITCH { + Some(Self::fast_switch_callback) + } else { + None + }; + drv.adjust_perf = if T::HAS_ADJUST_PERF { + Some(Self::adjust_perf_callback) + } else { + None + }; + drv.get_intermediate = if T::HAS_GET_INTERMEDIATE { + Some(Self::get_intermediate_callback) + } else { + None + }; + drv.target_intermediate = if T::HAS_TARGET_INTERMEDIATE { + Some(Self::target_intermediate_callback) + } else { + None + }; + drv.get = if T::HAS_GET { + Some(Self::get_callback) + } else { + None + }; + drv.update_limits = if T::HAS_UPDATE_LIMITS { + Some(Self::update_limits_callback) + } else { + None + }; + drv.bios_limit = if T::HAS_BIOS_LIMIT { + Some(Self::bios_limit_callback) + } else { + None + }; + drv.online = if T::HAS_ONLINE { + Some(Self::online_callback) + } else { + None + }; + drv.offline = if T::HAS_OFFLINE { + Some(Self::offline_callback) + } else { + None + }; + drv.exit = if T::HAS_EXIT { + Some(Self::exit_callback) + } else { + None + }; + drv.suspend = if T::HAS_SUSPEND { + Some(Self::suspend_callback) + } else { + None + }; + drv.resume = if T::HAS_RESUME { + Some(Self::resume_callback) + } else { + None + }; + drv.ready = if T::HAS_READY { + Some(Self::ready_callback) + } else { + None + }; + drv.set_boost = if T::HAS_SET_BOOST { + Some(Self::set_boost_callback) + } else { + None + }; + drv.register_em = if T::HAS_REGISTER_EM { + Some(Self::register_em_callback) + } else { + None + }; + + // Set driver data before registering the driver, as the cpufreq core may call few + // callbacks before `cpufreq_register_driver()` returns. + reg.set_data(data)?; + + // SAFETY: It is safe to register the driver with the cpufreq core in the C code. + to_result(unsafe { bindings::cpufreq_register_driver(reg.drv.get()) })?; + reg.registered = true; + Ok(reg) + } + + /// Returns the previous set data for a cpufreq driver. + pub fn data<D: ForeignOwnable>() -> Option<<D>::Borrowed<'static>> { + // SAFETY: The driver data is earlier set by us from [`set_data()`]. + let data = unsafe { bindings::cpufreq_get_driver_data() }; + if data.is_null() { + None + } else { + // SAFETY: The driver data is earlier set by us from [`set_data()`]. + Some(unsafe { D::borrow(data) }) + } + } + + // Sets the data for a cpufreq driver. + fn set_data(&mut self, data: T::Data) -> Result<()> { + let drv = self.drv.get_mut(); + + if drv.driver_data.is_null() { + // Pass the ownership of the data to the foreign interface. + drv.driver_data = <T::Data as ForeignOwnable>::into_foreign(data) as _; + Ok(()) + } else { + Err(EBUSY) + } + } + + // Clears and returns the data for a cpufreq driver. + fn clear_data(&mut self) -> Option<T::Data> { + let drv = self.drv.get_mut(); + + if drv.driver_data.is_null() { + None + } else { + // SAFETY: By the type invariants, we know that `self` owns a reference, so it is safe to + // relinquish it now. + let data = Some(unsafe { <T::Data as ForeignOwnable>::from_foreign(drv.driver_data) }); + drv.driver_data = ptr::null_mut(); + data + } + } +} + +// cpufreq driver callbacks. +impl<T: Driver> Registration<T> { + // Policy's init callback. + extern "C" fn init_callback(ptr: *mut bindings::cpufreq_policy) -> core::ffi::c_int { + from_result(|| { + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the + // duration of this call, so it is guaranteed to remain alive for the lifetime of + // `ptr`. + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; + + let data = T::init(&mut policy)?; + policy.set_data(data)?; + Ok(0) + }) + } + + // Policy's exit callback. + extern "C" fn exit_callback(ptr: *mut bindings::cpufreq_policy) -> core::ffi::c_int { + from_result(|| { + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the + // duration of this call, so it is guaranteed to remain alive for the lifetime of + // `ptr`. + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; + + let data = policy.clear_data(); + T::exit(&mut policy, data).map(|_| 0) + }) + } + + // Policy's online callback. + extern "C" fn online_callback(ptr: *mut bindings::cpufreq_policy) -> core::ffi::c_int { + from_result(|| { + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the + // duration of this call, so it is guaranteed to remain alive for the lifetime of + // `ptr`. + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; + T::online(&mut policy).map(|_| 0) + }) + } + + // Policy's offline callback. + extern "C" fn offline_callback(ptr: *mut bindings::cpufreq_policy) -> core::ffi::c_int { + from_result(|| { + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the + // duration of this call, so it is guaranteed to remain alive for the lifetime of + // `ptr`. + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; + T::offline(&mut policy).map(|_| 0) + }) + } + + // Policy's suspend callback. + extern "C" fn suspend_callback(ptr: *mut bindings::cpufreq_policy) -> core::ffi::c_int { + from_result(|| { + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the + // duration of this call, so it is guaranteed to remain alive for the lifetime of + // `ptr`. + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; + T::suspend(&mut policy).map(|_| 0) + }) + } + + // Policy's resume callback. + extern "C" fn resume_callback(ptr: *mut bindings::cpufreq_policy) -> core::ffi::c_int { + from_result(|| { + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the + // duration of this call, so it is guaranteed to remain alive for the lifetime of + // `ptr`. + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; + T::resume(&mut policy).map(|_| 0) + }) + } + + // Policy's ready callback. + extern "C" fn ready_callback(ptr: *mut bindings::cpufreq_policy) { + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the + // duration of this call, so it is guaranteed to remain alive for the lifetime of + // `ptr`. + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; + T::ready(&mut policy); + } + + // Policy's verify callback. + extern "C" fn verify_callback(ptr: *mut bindings::cpufreq_policy_data) -> core::ffi::c_int { + from_result(|| { + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the + // duration of this call, so it is guaranteed to remain alive for the lifetime of + // `ptr`. + let mut data = unsafe { PolicyData::from_raw_policy_data(ptr) }; + T::verify(&mut data).map(|_| 0) + }) + } + + // Policy's setpolicy callback. + extern "C" fn setpolicy_callback(ptr: *mut bindings::cpufreq_policy) -> core::ffi::c_int { + from_result(|| { + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the + // duration of this call, so it is guaranteed to remain alive for the lifetime of + // `ptr`. + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; + T::setpolicy(&mut policy).map(|_| 0) + }) + } + + // Policy's target callback. + extern "C" fn target_callback( + ptr: *mut bindings::cpufreq_policy, + target_freq: u32, + relation: u32, + ) -> core::ffi::c_int { + from_result(|| { + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the + // duration of this call, so it is guaranteed to remain alive for the lifetime of + // `ptr`. + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; + T::target(&mut policy, target_freq, Relation::new(relation)?).map(|_| 0) + }) + } + + // Policy's target_index callback. + extern "C" fn target_index_callback( + ptr: *mut bindings::cpufreq_policy, + index: u32, + ) -> core::ffi::c_int { + from_result(|| { + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the + // duration of this call, so it is guaranteed to remain alive for the lifetime of + // `ptr`. + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; + T::target_index(&mut policy, index).map(|_| 0) + }) + } + + // Policy's fast_switch callback. + extern "C" fn fast_switch_callback( + ptr: *mut bindings::cpufreq_policy, + target_freq: u32, + ) -> core::ffi::c_uint { + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the + // duration of this call, so it is guaranteed to remain alive for the lifetime of + // `ptr`. + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; + T::fast_switch(&mut policy, target_freq) + } + + // Policy's adjust_perf callback. + extern "C" fn adjust_perf_callback(cpu: u32, min_perf: u64, target_perf: u64, capacity: u64) { + if let Ok(mut policy) = Policy::from_cpu(cpu) { + T::adjust_perf(&mut policy, min_perf, target_perf, capacity); + } + } + + // Policy's get_intermediate callback. + extern "C" fn get_intermediate_callback( + ptr: *mut bindings::cpufreq_policy, + index: u32, + ) -> core::ffi::c_uint { + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the + // duration of this call, so it is guaranteed to remain alive for the lifetime of + // `ptr`. + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; + T::get_intermediate(&mut policy, index) + } + + // Policy's target_intermediate callback. + extern "C" fn target_intermediate_callback( + ptr: *mut bindings::cpufreq_policy, + index: u32, + ) -> core::ffi::c_int { + from_result(|| { + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the + // duration of this call, so it is guaranteed to remain alive for the lifetime of + // `ptr`. + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; + T::target_intermediate(&mut policy, index).map(|_| 0) + }) + } + + // Policy's get callback. + extern "C" fn get_callback(cpu: u32) -> core::ffi::c_uint { + // SAFETY: Get the policy for a CPU. + Policy::from_cpu(cpu).map_or(0, |mut policy| T::get(&mut policy).map_or(0, |f| f)) + } + + // Policy's update_limit callback. + extern "C" fn update_limits_callback(cpu: u32) { + // SAFETY: Get the policy for a CPU. + if let Ok(mut policy) = Policy::from_cpu(cpu) { + T::update_limits(&mut policy); + } + } + + // Policy's bios_limit callback. + extern "C" fn bios_limit_callback(cpu: i32, limit: *mut u32) -> core::ffi::c_int { + from_result(|| { + let mut policy = Policy::from_cpu(cpu as u32)?; + + // SAFETY: The pointer is guaranteed by the C code to be valid. + T::bios_limit(&mut policy, &mut (unsafe { *limit })).map(|_| 0) + }) + } + + // Policy's set_boost callback. + extern "C" fn set_boost_callback( + ptr: *mut bindings::cpufreq_policy, + state: i32, + ) -> core::ffi::c_int { + from_result(|| { + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the + // duration of this call, so it is guaranteed to remain alive for the lifetime of + // `ptr`. + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; + T::set_boost(&mut policy, state).map(|_| 0) + }) + } + + // Policy's register_em callback. + extern "C" fn register_em_callback(ptr: *mut bindings::cpufreq_policy) { + // SAFETY: `ptr` is valid by the contract with the C code. `policy` is alive only for the + // duration of this call, so it is guaranteed to remain alive for the lifetime of + // `ptr`. + let mut policy = unsafe { Policy::from_raw_policy(ptr) }; + T::register_em(&mut policy); + } +} + +impl<T: Driver> Drop for Registration<T> { + // Removes the registration from the kernel if it has completed successfully before. + fn drop(&mut self) { + pr_info!("Registration dropped\n"); + let drv = self.drv.get_mut(); + + if self.registered { + // SAFETY: The driver was earlier registered from `register()`. + unsafe { bindings::cpufreq_unregister_driver(drv) }; + } + + // Free the previously leaked memory to the C code. + if !drv.attr.is_null() { + // SAFETY: The pointer was earlier initialized from the result of `Box::leak`. + unsafe { drop(Box::from_raw(drv.attr)) }; + } + + // Free data + drop(self.clear_data()); + } +}
This extends the cpufreq bindings with bindings for registering a driver. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> --- rust/kernel/cpufreq.rs | 482 ++++++++++++++++++++++++++++++++++++++++- 1 file changed, 479 insertions(+), 3 deletions(-)