Zephyr: add more compliant implementation for irq_(un)lock

This change replaces the stubbed irq_(un)lock static functions
defined in task.h with new functions that behave more like the
Zephyr implementation of irq_(un)lock functions. This should
make the migration from interrupt_(dis|en)able to Zephyr more
seamless.

BRANCH=none
BUG=b:172060699
TEST=Added unit tests, make runtests -j, and built for various
     boards: eve, volteer, arcada_ish, atlas, hatch, kohaku,
     nocturne, samus, and scarlet

Signed-off-by: Yuval Peress <peress@chromium.org>
Change-Id: Ia7ad2b8d7d411a11699353bf5d3cc36a261fad14
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2511720

1 files changed, 23 insertions, 9 deletions

diff --git a/include/task.h b/include/task.h
index cf72e57680..680c753c62 100644
--- a/include/task.h
+++ b/include/task.h
@@ -85,15 +85,29 @@ void interrupt_enable(void);
  * interrupt_disable() and interrupt_enable().
  */
 #ifndef CONFIG_ZEPHYR
-__maybe_unused static inline uint32_t irq_lock(void)
-{
-	interrupt_disable();
-	return 0;
-}
-__maybe_unused static inline void irq_unlock(uint32_t key)
-{
-	interrupt_enable();
-}
+/**
+ * Perform the same operation as interrupt_disable but allow nesting. The
+ * return value from this function should be used as the argument to
+ * irq_unlock. Do not attempt to parse the value, it is a representation
+ * of the state and not an indication of any form of count.
+ *
+ * For more information see:
+ * https://docs.zephyrproject.org/latest/reference/kernel/other/interrupts.html#c.irq_lock
+ *
+ * @return Lock key to use for restoring the state via irq_unlock.
+ */
+uint32_t irq_lock(void);
+
+/**
+ * Perform the same operation as interrupt_enable but allow nesting. The key
+ * should be the unchanged value returned by irq_lock.
+ *
+ * For more information see:
+ * https://docs.zephyrproject.org/latest/reference/kernel/other/interrupts.html#c.irq_unlock
+ *
+ * @param key The lock-out key used to restore the interrupt state.
+ */
+void irq_unlock(uint32_t key);
 #endif /* CONFIG_ZEPHYR */
 
 /**