abuf: Provide a constant buffer

Add a new initialiser which can accept a constant pointer.

Signed-off-by: Simon Glass <sjg@chromium.org>

3 files changed, 41 insertions, 0 deletions

diff --git a/include/abuf.h b/include/abuf.h
index de21cefade4..62ff6499a0c 100644
--- a/include/abuf.h
+++ b/include/abuf.h
@@ -158,6 +158,19 @@ void abuf_init_move(struct abuf *abuf, void *data, size_t size);
 void abuf_init_set(struct abuf *abuf, void *data, size_t size);
 
 /**
+ * abuf_init_const() - Set up a new const abuf
+ *
+ * Inits a new abuf and sets up its (unallocated) data. The only current
+ * difference between this and abuf_init_set() is the 'data' parameter is a
+ * const pointer. At some point a flag could be used to indicate const-ness.
+ *
+ * @abuf: abuf to set up
+ * @data: New contents of abuf
+ * @size: New size of abuf
+ */
+void abuf_init_const(struct abuf *abuf, const void *data, size_t size);
+
+/**
  * abuf_uninit() - Free any memory used by an abuf
  *
  * The buffer must be inited before this can be called.
diff --git a/lib/abuf.c b/lib/abuf.c
index 8156177c773..61adf7fc6b1 100644
--- a/lib/abuf.c
+++ b/lib/abuf.c
@@ -119,6 +119,12 @@ void abuf_init_set(struct abuf *abuf, void *data, size_t size)
 	abuf_set(abuf, data, size);
 }
 
+void abuf_init_const(struct abuf *abuf, const void *data, size_t size)
+{
+	/* for now there is no flag indicating that the abuf data is constant */
+	abuf_init_set(abuf, (void *)data, size);
+}
+
 void abuf_init_move(struct abuf *abuf, void *data, size_t size)
 {
 	abuf_init_set(abuf, data, size);
diff --git a/test/lib/abuf.c b/test/lib/abuf.c
index 5d61f9261c6..b38690fe1a9 100644
--- a/test/lib/abuf.c
+++ b/test/lib/abuf.c
@@ -46,6 +46,28 @@ static int lib_test_abuf_set(struct unit_test_state *uts)
 }
 LIB_TEST(lib_test_abuf_set, 0);
 
+/* Test abuf_init_const() */
+static int lib_test_abuf_init_const(struct unit_test_state *uts)
+{
+	struct abuf buf;
+	ulong start;
+	void *ptr;
+
+	start = ut_check_free();
+
+	ptr = map_sysmem(0x100, 0);
+
+	abuf_init_const(&buf, ptr, 10);
+	ut_asserteq_ptr(ptr, buf.data);
+	ut_asserteq(10, buf.size);
+
+	/* No memory should have been allocated */
+	ut_assertok(ut_check_delta(start));
+
+	return 0;
+}
+LIB_TEST(lib_test_abuf_init_const, 0);
+
 /* Test abuf_map_sysmem() and abuf_addr() */
 static int lib_test_abuf_map_sysmem(struct unit_test_state *uts)
 {