[rtems commit] Remove excessive locking from cache operations.

[Sebastian Huber]

Module:    rtems
Branch:    master
Commit:    fd10817a8355653043f8addfe2ef975bedad093a
Changeset: http://git.rtems.org/rtems/commit/?id=fd10817a8355653043f8addfe2ef975bedad093a

Author:    Alexei Pososin <m09123874 at bk.ru>
Date:      Thu May 11 14:33:10 2017 +0100

Remove excessive locking from cache operations.

According to manual, the used operations (Clean Line by PA, Clean and
Invalidate Line by PA, Cache Sync) are atomic and do not require
locking.

Update #3007.

---

 c/src/lib/libbsp/arm/shared/arm-l2c-310/cache_.h | 44 +++++-------------------
 1 file changed, 9 insertions(+), 35 deletions(-)

diff --git a/c/src/lib/libbsp/arm/shared/arm-l2c-310/cache_.h b/c/src/lib/libbsp/arm/shared/arm-l2c-310/cache_.h
index f7017b7..81b34a6 100644
--- a/c/src/lib/libbsp/arm/shared/arm-l2c-310/cache_.h
+++ b/c/src/lib/libbsp/arm/shared/arm-l2c-310/cache_.h
@@ -882,30 +882,17 @@ l2c_310_flush_range( const void* d_addr, const size_t n_bytes )
     & ~L2C_310_DATA_LINE_MASK;
   const uint32_t ADDR_LAST         =
     (uint32_t)( (size_t)d_addr + n_bytes - 1 );
-  uint32_t       block_end         =
-    L2C_310_MIN( ADDR_LAST, adx + L2C_310_MAX_LOCKING_BYTES );
   volatile L2CC *l2cc = (volatile L2CC *) BSP_ARM_L2C_310_BASE;
 
   if ( n_bytes == 0 ) {
     return;
   }
 
-  for (;
-       adx      <= ADDR_LAST;
-       adx       = block_end + 1,
-       block_end = L2C_310_MIN( ADDR_LAST, adx + L2C_310_MAX_LOCKING_BYTES )) {
-    rtems_interrupt_lock_context lock_context;
-
-    rtems_interrupt_lock_acquire( &l2c_310_lock, &lock_context );
-
-    for (; adx <= block_end; adx += CPU_DATA_CACHE_ALIGNMENT ) {
-      l2c_310_flush_1_line( l2cc, adx );
-    }
-
-    l2c_310_sync( l2cc );
-
-    rtems_interrupt_lock_release( &l2c_310_lock, &lock_context );
+  for (; adx <= ADDR_LAST; adx += CPU_DATA_CACHE_ALIGNMENT ) {
+    l2c_310_flush_1_line( l2cc, adx );
   }
+
+  l2c_310_sync( l2cc );
 }
 
 static inline void
@@ -950,31 +937,18 @@ l2c_310_invalidate_range( const void* d_addr, const size_t n_bytes )
     & ~L2C_310_DATA_LINE_MASK;
   const uint32_t ADDR_LAST         =
     (uint32_t)( (size_t)d_addr + n_bytes - 1 );
-  uint32_t       block_end         =
-    L2C_310_MIN( ADDR_LAST, adx + L2C_310_MAX_LOCKING_BYTES );
   volatile L2CC *l2cc = (volatile L2CC *) BSP_ARM_L2C_310_BASE;
 
   if ( n_bytes == 0 ) {
     return;
   }
 
-  for (;
-       adx      <= ADDR_LAST;
-       adx       = block_end + 1,
-       block_end = L2C_310_MIN( ADDR_LAST, adx + L2C_310_MAX_LOCKING_BYTES )) {
-    rtems_interrupt_lock_context lock_context;
-
-    rtems_interrupt_lock_acquire( &l2c_310_lock, &lock_context );
-
-    for (; adx <= block_end; adx += CPU_DATA_CACHE_ALIGNMENT ) {
-      /* Invalidate L2 cache line */
-      l2cc->inv_pa = adx;
-    }
-
-    l2c_310_sync( l2cc );
-
-    rtems_interrupt_lock_release( &l2c_310_lock, &lock_context );
+  for (; adx <= ADDR_LAST; adx += CPU_DATA_CACHE_ALIGNMENT ) {
+    /* Invalidate L2 cache line */
+    l2cc->inv_pa = adx;
   }
+
+  l2c_310_sync( l2cc );
 }