Add read_poll_timeout_atomic function which polls periodically until a
condition is met, an error occurs, or the attempt limit is reached.
This helper is used to wait for a condition in atomic context,
mirroring the C's read_poll_timeout_atomic().
In atomic context, the timekeeping infrastructure is unavailable, so
reliable time-based timeouts cannot be implemented. So instead, the
helper accepts a maximum number of attempts and busy-waits (udelay +
cpu_relax) between tries.
v4:
- update the comment on udelay
- add Alice and Andreas' Reviewed-by
v3: https://lore.kernel.org/lkml/20251026125458.2772103-1-fujita.tomonori@gmail.com/
- revert the function name
- simplify the example code
- add debug_assert to check the range for udelay
v2: https://lore.kernel.org/lkml/20251021071146.2357069-1-fujita.tomonori@gmail.com/
- use the attempt limit instead of timeout
- rename the function to read_poll_count_atomic
- add the comment about C's udelay behavior.
v1: https://lore.kernel.org/lkml/20250821035710.3692455-1-fujita.tomonori@gmail.com/
FUJITA Tomonori (2):
rust: add udelay() function
rust: Add read_poll_timeout_atomic function
rust/helpers/time.c | 5 +++
rust/kernel/io/poll.rs | 72 ++++++++++++++++++++++++++++++++++++++-
rust/kernel/time/delay.rs | 37 ++++++++++++++++++++
3 files changed, 113 insertions(+), 1 deletion(-)
base-commit: b0b7301b004301afe920b3d08caa6171dd3f4011
--
2.43.0