From 273834ee84814ba543d17c6c2b8a1a4d2c3ed2fa Mon Sep 17 00:00:00 2001
From: Romain Goyet <romain.goyet@numworks.com>
Date: Sun, 15 Dec 2019 17:13:27 -0500
Subject: [PATCH] [ion/cache] Improve cache cleaning

 - Avoid fetching CCSIDR twice
 - Use for loop instead of do/while
 - Only compute the target register once
 - Avoid an useless nop
---
 ion/src/device/n0110/drivers/cache.cpp | 39 +++++++++++++-------------
 ion/src/device/shared/regs/cortex.h    |  1 +
 2 files changed, 21 insertions(+), 19 deletions(-)

diff --git a/ion/src/device/n0110/drivers/cache.cpp b/ion/src/device/n0110/drivers/cache.cpp
index f14bee613..87b1a36f2 100644
--- a/ion/src/device/n0110/drivers/cache.cpp
+++ b/ion/src/device/n0110/drivers/cache.cpp
@@ -17,28 +17,29 @@ void privateCleanInvalidateDisableDCache(bool clean, bool invalidate, bool disab
     dsb();
   }
 
-  uint32_t sets = CORTEX.CCSIDR()->getNUMSETS();
-  uint32_t ways = CORTEX.CCSIDR()->getASSOCIATIVITY();
+  // Pick the right DC??SW register according to invalidate/disable parameters
+  volatile CORTEX::DCSW * target = nullptr;
+  if (clean && invalidate) {
+    target = CORTEX.DCCISW();
+  } else if (clean) {
+    target = CORTEX.DCCSW();
+  } else {
+    assert(invalidate);
+    target = CORTEX.DCISW();
+  }
 
-  do {
-    uint32_t w = ways;
-    do {
+  class CORTEX::CCSIDR ccsidr = CORTEX.CCSIDR()->get();
+  uint32_t sets = ccsidr.getNUMSETS();
+  uint32_t ways = ccsidr.getASSOCIATIVITY();
+
+  for (int set = sets; set >= 0; set--) {
+    for (int way = ways; way >= 0; way--) {
       class CORTEX::DCSW dcsw;
-      dcsw.setSET(sets);
-      dcsw.setWAY(w);
-      volatile CORTEX::DCSW * target = nullptr;
-      if (clean && invalidate) {
-        target = CORTEX.DCCISW();
-      } else if (clean) {
-        target = CORTEX.DCCSW();
-      } else {
-        assert(invalidate);
-        target = CORTEX.DCISW();
-      }
+      dcsw.setSET(set);
+      dcsw.setWAY(way);
       target->set(dcsw);
-      __asm volatile("nop");
-    } while (w-- != 0);
-  } while (sets-- != 0);
+    }
+  }
 
   dsb();
   isb();
diff --git a/ion/src/device/shared/regs/cortex.h b/ion/src/device/shared/regs/cortex.h
index 15d6e4ace..2c71c0fa2 100644
--- a/ion/src/device/shared/regs/cortex.h
+++ b/ion/src/device/shared/regs/cortex.h
@@ -72,6 +72,7 @@ public:
 #if REGS_CORTEX_CONFIG_CACHE
   class CCSIDR : public Register32 {
   public:
+    using Register32::Register32;
     REGS_FIELD(ASSOCIATIVITY, uint16_t, 12, 3);
     REGS_FIELD(NUMSETS, uint16_t, 27, 13);
   };