diff --git a/rust/kernel/io/poll.rs b/rust/kernel/io/poll.rs index 8f8886543f34..ebc29023d59d 100644 --- a/rust/kernel/io/poll.rs +++ b/rust/kernel/io/poll.rs @@ -8,7 +8,15 @@ use crate::{ error::{code::*, Result}, processor::cpu_relax, task::might_sleep, - time::{delay::fsleep, Delta, Instant, Monotonic}, + time::{ + delay::{ + fsleep, + udelay, // + }, + Delta, + Instant, + Monotonic, // + }, }; /// Polls periodically until a condition is met, an error occurs, @@ -96,3 +104,70 @@ where cpu_relax(); } } + +/// Polls periodically until a condition is met, an error occurs, +/// or the attempt limit is reached. +/// +/// The function repeatedly executes the given operation `op` closure and +/// checks its result using the condition closure `cond`. +/// +/// If `cond` returns `true`, the function returns successfully with the result of `op`. +/// Otherwise, it performs a busy wait for a duration specified by `delay_delta` +/// before executing `op` again. +/// +/// This process continues until either `op` returns an error, `cond` +/// returns `true`, or the attempt limit specified by `retry` is reached. +/// +/// # Errors +/// +/// If `op` returns an error, then that error is returned directly. +/// +/// If the attempt limit specified by `retry` is reached, then +/// `Err(ETIMEDOUT)` is returned. +/// +/// # Examples +/// +/// ```no_run +/// use kernel::io::{poll::read_poll_timeout_atomic, Io}; +/// use kernel::time::Delta; +/// +/// const HW_READY: u16 = 0x01; +/// +/// fn wait_for_hardware(io: &Io) -> Result { +/// read_poll_timeout_atomic( +/// // The `op` closure reads the value of a specific status register. +/// || io.try_read16(0x1000), +/// // The `cond` closure takes a reference to the value returned by `op` +/// // and checks whether the hardware is ready. +/// |val: &u16| *val == HW_READY, +/// Delta::from_micros(50), +/// 1000, +/// )?; +/// Ok(()) +/// } +/// ``` +pub fn read_poll_timeout_atomic( + mut op: Op, + mut cond: Cond, + delay_delta: Delta, + retry: usize, +) -> Result +where + Op: FnMut() -> Result, + Cond: FnMut(&T) -> bool, +{ + for _ in 0..retry { + let val = op()?; + if cond(&val) { + return Ok(val); + } + + if !delay_delta.is_zero() { + udelay(delay_delta); + } + + cpu_relax(); + } + + Err(ETIMEDOUT) +}