Remove invalid code

Author: rcitach

bsp/xuantie/virt64/c906/libcpu/cache.c

@@ -14,16 +14,6 @@
 #include <riscv.h>
 #include <cache.h>
 
-rt_inline rt_uint32_t rt_cpu_icache_line_size()
-{
-    return 0;
-}
-
-rt_inline rt_uint32_t rt_cpu_dcache_line_size()
-{
-    return 0;
-}
-
 void rt_hw_cpu_icache_ops(int ops, void *addr, int size)
 {
     if (ops == RT_HW_CACHE_INVALIDATE)
@@ -44,16 +34,9 @@ void rt_hw_cpu_dcache_ops(int ops, void *addr, int size)
     }
 }
 
-rt_base_t rt_hw_cpu_icache_status_local()
-{
-    return 0;
-}
-
-rt_base_t rt_hw_cpu_dcache_status()
-{
-    return 0;
-}
-
 void rt_hw_sync_cache_local(void *addr, int size)
 {
+    rt_hw_cpu_dcache_clean_local(addr, size);
+    rt_hw_cpu_icache_invalidate_local(addr, size);
+    return;
 }

bsp/xuantie/virt64/c906/libcpu/cache.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2006-2021, RT-Thread Development Team
+ * Copyright (c) 2006-2025 RT-Thread Development Team
  *
  * SPDX-License-Identifier: Apache-2.0
  *
@@ -47,14 +47,15 @@ rt_always_inline void rt_hw_cpu_dcache_clean_and_invalidate_all_local(void)
 {
 }
 
+/*use fence.i to invalidate all icache*/
 rt_always_inline void rt_hw_cpu_icache_invalidate_local(void *addr, int size)
 {
-    RT_UNUSED(addr);
-    RT_UNUSED(size);
+    __asm__ __volatile__("fence.i" ::: "memory");
 }
-
+/*use fence.i to invalidate all icache*/
 rt_always_inline void rt_hw_cpu_icache_invalidate_all_local(void)
 {
+    __asm__ __volatile__("fence.i" ::: "memory");
 }
 
 /**
@@ -75,7 +76,10 @@ rt_always_inline void rt_hw_cpu_icache_invalidate_all_local(void)
 #define rt_hw_icache_invalidate_all rt_hw_cpu_icache_invalidate_all
 
 /** instruction barrier */
-static inline void rt_hw_cpu_sync(void) {}
+static inline void rt_hw_cpu_sync(void)
+{
+    __asm__ __volatile__("fence.i" ::: "memory");
+}
 
 /**
  * @brief local cpu icahce & dcache synchronization