abuf: Add a way to set up an abuf with a given address

In some cases it is convenient to provide an address when initing an
abuf, instead of a pointer. Add a function for this.

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

include/abuf.h

@@ -202,6 +202,18 @@ void abuf_init_set(struct abuf *abuf, void *data, size_t size);
  */
 void abuf_init_const(struct abuf *abuf, const void *data, size_t size);
 
+/**
+ * abuf_init_const_addr() - Set up a new buffer at a given address
+ *
+ * This is similar to abuf_init_const() except that it takes an address instead
+ * of a pointer. Note that the abuf is unallocated.
+ *
+ * @abuf: abuf to set up
+ * @addr: Address to use
+ * @size: Size of buffer
+ */
+void abuf_init_const_addr(struct abuf *abuf, ulong addr, size_t size);
+
 /**
  * abuf_init_size() - Set up an allocated abuf
  *

lib/abuf.c

@@ -183,6 +183,13 @@ void abuf_init_const(struct abuf *abuf, const void *data, size_t size)
 	abuf_init_set(abuf, (void *)data, size);
 }
 
+#ifndef USE_HOSTCC
+void abuf_init_const_addr(struct abuf *abuf, ulong addr, size_t size)
+{
+	return abuf_init_const(abuf, map_sysmem(addr, size), size);
+}
+#endif
+
 void abuf_init_move(struct abuf *abuf, void *data, size_t size)
 {
 	abuf_init_set(abuf, data, size);

test/lib/abuf.c

@@ -68,6 +68,28 @@ static int lib_test_abuf_init_const(struct unit_test_state *uts)
 }
 LIB_TEST(lib_test_abuf_init_const, 0);
 
+/* Test abuf_init_const_addr() */
+static int lib_test_abuf_init_const_addr(struct unit_test_state *uts)
+{
+	struct abuf buf;
+	ulong start;
+	void *ptr;
+
+	start = ut_check_free();
+
+	ptr = map_sysmem(0x100, 0);
+
+	abuf_init_const_addr(&buf, 0x100, 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_addr, 0);
+
 /* Test abuf_map_sysmem() and abuf_addr() */
 static int lib_test_abuf_map_sysmem(struct unit_test_state *uts)
 {