[PATCH v4 16/35] acpi: Support writing a string

[Simon Glass <sjg@chromium.org>]

ACPI supports storing a simple null-terminated string. Add support for
this.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Wolfgang Wallner <wolfgang.wallner@br-automation.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
---

Changes in v4:
- Change 'nul' to 'null' in commit message and acpigen_write_string()
- Move emit->write comment changes to previous patches

 include/acpi/acpigen.h | 10 ++++++++++
 lib/acpi/acpigen.c     |  6 ++++++
 test/dm/acpigen.c      | 28 ++++++++++++++++++++++++++++
 3 files changed, 44 insertions(+)

diff --git a/include/acpi/acpigen.h b/include/acpi/acpigen.h
index 9e52ec589f..14b96203a9 100644
--- a/include/acpi/acpigen.h
+++ b/include/acpi/acpigen.h
@@ -24,6 +24,7 @@ enum {
 	BYTE_PREFIX		= 0x0a,
 	WORD_PREFIX		= 0x0b,
 	DWORD_PREFIX		= 0x0c,
+	STRING_PREFIX		= 0x0d,
 	QWORD_PREFIX		= 0x0e,
 	PACKAGE_OP		= 0x12,
 };
@@ -155,4 +156,13 @@ char *acpigen_write_package(struct acpi_ctx *ctx, int nr_el);
  */
 void acpigen_write_integer(struct acpi_ctx *ctx, u64 data);
 
+/**
+ * acpigen_write_string() - Write a string
+ *
+ * This writes a STRING_PREFIX followed by a null-terminated string
+ *
+ * @ctx: ACPI context pointer
+ * @str: String to write
+ */
+void acpigen_write_string(struct acpi_ctx *ctx, const char *str);
 #endif
diff --git a/lib/acpi/acpigen.c b/lib/acpi/acpigen.c
index 27d4eab7a6..b254ef6c9a 100644
--- a/lib/acpi/acpigen.c
+++ b/lib/acpi/acpigen.c
@@ -147,3 +147,9 @@ void acpigen_emit_string(struct acpi_ctx *ctx, const char *str)
 	acpigen_emit_stream(ctx, str, str ? strlen(str) : 0);
 	acpigen_emit_byte(ctx, '\0');
 }
+
+void acpigen_write_string(struct acpi_ctx *ctx, const char *str)
+{
+	acpigen_emit_byte(ctx, STRING_PREFIX);
+	acpigen_emit_string(ctx, str);
+}
diff --git a/test/dm/acpigen.c b/test/dm/acpigen.c
index 187001d2fc..c360f55dd3 100644
--- a/test/dm/acpigen.c
+++ b/test/dm/acpigen.c
@@ -23,6 +23,7 @@
 #define ACPI_CONTEXT_SIZE	150
 
 #define TEST_STRING	"frogmore"
+#define TEST_STRING2	"ranch"
 #define TEST_STREAM2	"\xfa\xde"
 
 #define TEST_INT8	0x7d
@@ -477,3 +478,30 @@ static int dm_test_acpi_integer(struct unit_test_state *uts)
 	return 0;
 }
 DM_TEST(dm_test_acpi_integer, 0);
+
+/* Test writing a string */
+static int dm_test_acpi_string(struct unit_test_state *uts)
+{
+	struct acpi_ctx *ctx;
+	u8 *ptr;
+
+	ut_assertok(alloc_context(&ctx));
+
+	ptr = acpigen_get_current(ctx);
+
+	acpigen_write_string(ctx, TEST_STRING);
+	acpigen_write_string(ctx, TEST_STRING2);
+
+	ut_asserteq(2 + sizeof(TEST_STRING) + sizeof(TEST_STRING2),
+		    acpigen_get_current(ctx) - ptr);
+	ut_asserteq(STRING_PREFIX, ptr[0]);
+	ut_asserteq_str(TEST_STRING, (char *)ptr + 1);
+	ptr += 1 + sizeof(TEST_STRING);
+	ut_asserteq(STRING_PREFIX, ptr[0]);
+	ut_asserteq_str(TEST_STRING2, (char *)ptr + 1);
+
+	free_context(&ctx);
+
+	return 0;
+}
+DM_TEST(dm_test_acpi_string, 0);
-- 
2.27.0.383.g050319c2ae-goog