Add calls to tight_loop_contents in a few more places. (#1401)

Fixes #1290
raspberrypi · Dec 15, 2023 · 7ed83dd · 7ed83dd
1 parent d92e26a
commit 7ed83dd
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Showing 2 changed files with 12 additions and 4 deletions.
diff --git a/src/rp2_common/hardware_sync/include/hardware/sync.h b/src/rp2_common/hardware_sync/include/hardware/sync.h
@@ -262,7 +262,9 @@ __force_inline static void spin_lock_unsafe_blocking(spin_lock_t *lock) {
     // Note we don't do a wfe or anything, because by convention these spin_locks are VERY SHORT LIVED and NEVER BLOCK and run
     // with INTERRUPTS disabled (to ensure that)... therefore nothing on our core could be blocking us, so we just need to wait on another core
     // anyway which should be finished soon
-    while (__builtin_expect(!*lock, 0));
+    while (__builtin_expect(!*lock, 0)) {
+        tight_loop_contents();
+    }
     __mem_fence_acquire();
 }
 

diff --git a/src/rp2_common/hardware_xosc/xosc.c b/src/rp2_common/hardware_xosc/xosc.c
@@ -37,7 +37,9 @@ void xosc_init(void) {
     hw_set_bits(&xosc_hw->ctrl, XOSC_CTRL_ENABLE_VALUE_ENABLE << XOSC_CTRL_ENABLE_LSB);
 
     // Wait for XOSC to be stable
-    while(!(xosc_hw->status & XOSC_STATUS_STABLE_BITS));
+    while(!(xosc_hw->status & XOSC_STATUS_STABLE_BITS)) {
+        tight_loop_contents();
+    }
 }
 
 void xosc_disable(void) {
@@ -46,12 +48,16 @@ void xosc_disable(void) {
     tmp |= (XOSC_CTRL_ENABLE_VALUE_DISABLE << XOSC_CTRL_ENABLE_LSB);
     xosc_hw->ctrl = tmp;
     // Wait for stable to go away
-    while(xosc_hw->status & XOSC_STATUS_STABLE_BITS);
+    while(xosc_hw->status & XOSC_STATUS_STABLE_BITS) {
+        tight_loop_contents();
+    }
 }
 
 void xosc_dormant(void) {
     // WARNING: This stops the xosc until woken up by an irq
     xosc_hw->dormant = XOSC_DORMANT_VALUE_DORMANT;
     // Wait for it to become stable once woken up
-    while(!(xosc_hw->status & XOSC_STATUS_STABLE_BITS));
+    while(!(xosc_hw->status & XOSC_STATUS_STABLE_BITS)) {
+        tight_loop_contents();
+    }
 }