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-rw-r--r--rust/kernel/io/poll.rs77
1 files changed, 76 insertions, 1 deletions
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<const SIZE: usize>(io: &Io<SIZE>) -> 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<Op, Cond, T>(
+ mut op: Op,
+ mut cond: Cond,
+ delay_delta: Delta,
+ retry: usize,
+) -> Result<T>
+where
+ Op: FnMut() -> Result<T>,
+ 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)
+}