hwstub/qeditor: add support for atomic read/writes

The current code assumed that READ/WRITE would produce atomic read/writes for
8/16/32-bit words, which in turned put assumption on the memcpy function.
Since some memcpy implementation do not always guarantee such strong assumption,
introduce two new operation READ/WRITE_ATOMIC which provide the necessary
tools to do correct read and write to register in a single memory access.

Change-Id: I37451bd5057bb0dcaf5a800d8aef8791c792a090

1 files changed, 61 insertions, 0 deletions

diff --git a/utils/hwstub/stub/asm/mips/atomic_rw.S b/utils/hwstub/stub/asm/mips/atomic_rw.S
new file mode 100644
index 0000000000..47c4213a5d
--- /dev/null
+++ b/utils/hwstub/stub/asm/mips/atomic_rw.S
@@ -0,0 +1,61 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ *
+ * Copyright (C) 2014 by Marcin Bukat
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+#include "mips.h"
+
+    .set noreorder
+    .section   .text, "ax", %progbits
+    .global    target_read8
+    .type      target_read8, %function
+    .global    target_read16
+    .type      target_read16, %function
+    .global    target_read32
+    .type      target_read32, %function
+    .global    target_write8
+    .type      target_write8, %function
+    .global    target_write16
+    .type      target_write16, %function
+    .global    target_write32
+    .type      target_write32, %function
+
+target_read8:
+    jr ra
+    lbu v0, 0(a0)
+
+target_read16:
+    jr ra
+    lhu v0, 0(a0)
+
+target_read32:
+    jr ra
+    lw v0, 0(a0)
+
+target_write8:
+    jr ra
+    sb a1, 0(a0)
+
+target_write16:
+    jr ra
+    sh a1, 0(a0)
+
+target_write32:
+    jr ra
+    sw a1, 0(a0)
+
+    .set reorder