commit 7ed83dd2d364261da24f7579483d6f3a9ec60951
author Andrew Scheller <andrew.scheller@raspberrypi.com> Fri Dec 15 13:36:51 2023 +0000
committer GitHub <noreply@github.com> Fri Dec 15 13:36:51 2023 +0000
tree ae02f5d9372f3b556b698cad1350fdc57ae42728
parent d92e26afca70237e4edb5573cedd03ff4501267a

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

Fixes #1290

src/rp2_common/hardware_sync/include/hardware/sync.h

diff --git a/src/rp2_common/hardware_sync/include/hardware/sync.h b/src/rp2_common/hardware_sync/include/hardware/sync.h
index b15f36b..35bd783 100644
--- a/src/rp2_common/hardware_sync/include/hardware/sync.h
+++ b/src/rp2_common/hardware_sync/include/hardware/sync.h
@@ -262,7 +262,9 @@
     // 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();
 }
 

src/rp2_common/hardware_xosc/xosc.c

diff --git a/src/rp2_common/hardware_xosc/xosc.c b/src/rp2_common/hardware_xosc/xosc.c
index 03e6785..e226022 100644
--- a/src/rp2_common/hardware_xosc/xosc.c
+++ b/src/rp2_common/hardware_xosc/xosc.c
@@ -37,7 +37,9 @@
     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 @@
     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();
+    }
 }