1 files changed, 30 insertions, 22 deletions

diff --git a/bsps/shared/grlib/uart/apbuart_polled.c b/bsps/shared/grlib/uart/apbuart_polled.c
index b83af56b09..84c31795df 100644
--- a/bsps/shared/grlib/uart/apbuart_polled.c
+++ b/bsps/shared/grlib/uart/apbuart_polled.c
@@ -1,8 +1,17 @@
 /* SPDX-License-Identifier: BSD-2-Clause */
 
+/**
+ * @file
+ *
+ * @ingroup RTEMSDeviceGRLIBAPBUART
+ *
+ * @brief This source file contains the implementation of
+ *   apbuart_outbyte_wait(), apbuart_outbyte_polled(), and
+ *   apbuart_inbyte_nonblocking().
+ */
+
 /*
- *  COPYRIGHT (c) 2010.
- *  Cobham Gaisler AB.
+ * Copyright (C) 2021 embedded brains GmbH & Co. KG
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -27,38 +36,37 @@
  */
 
 #include <grlib/apbuart.h>
+#include <grlib/io.h>
 
-#include <rtems/score/cpuimpl.h>
+#include <rtems/dev/io.h>
 
-void apbuart_outbyte_wait(const struct apbuart_regs *regs)
+void apbuart_outbyte_wait( const apbuart *regs )
 {
-  while ( (regs->status & APBUART_STATUS_TE) == 0 ) {
-    /* Lower bus utilization while waiting for UART */
-    _CPU_Instruction_no_operation();
-    _CPU_Instruction_no_operation();
-    _CPU_Instruction_no_operation();
-    _CPU_Instruction_no_operation();
-    _CPU_Instruction_no_operation();
-    _CPU_Instruction_no_operation();
-    _CPU_Instruction_no_operation();
-    _CPU_Instruction_no_operation();
+  while ( ( grlib_load_32( &regs->status ) & APBUART_STATUS_TE ) == 0 ) {
+    _IO_Relax();
   }
 }
 
-void apbuart_outbyte_polled(struct apbuart_regs *regs, char ch)
+void apbuart_outbyte_polled( apbuart *regs, char ch)
 {
-  apbuart_outbyte_wait(regs);
-  regs->data = (uint8_t) ch;
+  apbuart_outbyte_wait( regs );
+  grlib_store_32( &regs->data, (uint8_t) ch );
 }
 
-int apbuart_inbyte_nonblocking(struct apbuart_regs *regs)
+int apbuart_inbyte_nonblocking( apbuart *regs )
 {
-  /* Clear errors */
-  regs->status = ~APBUART_STATUS_ERR;
+  uint32_t status;
+
+  status = grlib_load_32( &regs->status );
+
+  /* Clear errors, writes to non-error flags are ignored */
+  status &= ~( APBUART_STATUS_FE | APBUART_STATUS_PE | APBUART_STATUS_OV |
+    APBUART_STATUS_BR );
+  grlib_store_32( &regs->status, status );
 
-  if ((regs->status & APBUART_STATUS_DR) == 0) {
+  if ( ( status & APBUART_STATUS_DR ) == 0 ) {
     return -1;
   }
 
-  return (uint8_t) regs->data;
+  return (int) APBUART_DATA_DATA_GET( grlib_load_32( &regs->data ) );
 }