acpi: Add support for DSDT generation

Some devices need to inject extra code into the Differentiated System
Descriptor Table (DSDT). Add a method to handle 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>
[bmeng: correct one typo in inject_dsdt() comments]
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>

arch/sandbox/dts/test.dts

@@ -257,6 +257,7 @@
 	acpi_test1: acpi-test {
 		compatible = "denx,u-boot-acpi-test";
 		acpi-ssdt-test-data = "ab";
+		acpi-dsdt-test-data = "hi";
 		child {
 			compatible = "denx,u-boot-acpi-test";
 		};
@@ -265,6 +266,7 @@
 	acpi_test2: acpi-test2 {
 		compatible = "denx,u-boot-acpi-test";
 		acpi-ssdt-test-data = "cd";
+		acpi-dsdt-test-data = "jk";
 	};
 
 	clocks {

drivers/core/acpi.c

@@ -22,12 +22,14 @@
 enum gen_type_t {
 	TYPE_NONE,
 	TYPE_SSDT,
+	TYPE_DSDT,
 };
 
 /* Type of method to call */
 enum method_t {
 	METHOD_WRITE_TABLES,
 	METHOD_FILL_SSDT,
+	METHOD_INJECT_DSDT,
 };
 
 /* Prototype for all methods */
@@ -144,7 +146,9 @@ static int sort_acpi_item_type(struct acpi_ctx *ctx, void *start,
 	void *end = ctx->current;
 
 	ptr = start;
-	order = ofnode_read_chosen_prop("u-boot,acpi-ssdt-order", &size);
+	order = ofnode_read_chosen_prop(type == TYPE_DSDT ?
+					"u-boot,acpi-dsdt-order" :
+					"u-boot,acpi-ssdt-order", &size);
 	if (!order) {
 		log_warning("Failed to find ordering, leaving as is\n");
 		return 0;
@@ -198,6 +202,8 @@ acpi_method acpi_get_method(struct udevice *dev, enum method_t method)
 			return aops->write_tables;
 		case METHOD_FILL_SSDT:
 			return aops->fill_ssdt;
+		case METHOD_INJECT_DSDT:
+			return aops->inject_dsdt;
 		}
 	}
 
@@ -256,6 +262,23 @@ int acpi_fill_ssdt(struct acpi_ctx *ctx)
 	return ret;
 }
 
+int acpi_inject_dsdt(struct acpi_ctx *ctx)
+{
+	void *start = ctx->current;
+	int ret;
+
+	log_debug("Writing DSDT tables\n");
+	item_count = 0;
+	ret = acpi_recurse_method(ctx, dm_root(), METHOD_INJECT_DSDT,
+				  TYPE_DSDT);
+	log_debug("Writing DSDT finished, err=%d\n", ret);
+	ret = sort_acpi_item_type(ctx, start, TYPE_DSDT);
+	if (ret)
+		return log_msg_ret("build", ret);
+
+	return ret;
+}
+
 int acpi_write_dev_tables(struct acpi_ctx *ctx)
 {
 	int ret;

include/dm/acpi.h

@@ -82,11 +82,31 @@ struct acpi_ops {
 	 * whatever ACPI code is needed by this device. It will end up in the
 	 * SSDT table.
 	 *
+	 * Note that this is called 'fill' because the entire contents of the
+	 * SSDT is build by calling this method on all devices.
+	 *
 	 * @dev: Device to write
 	 * @ctx: ACPI context to use
 	 * @return 0 if OK, -ve on error
 	 */
 	int (*fill_ssdt)(const struct udevice *dev, struct acpi_ctx *ctx);
+
+	/**
+	 * inject_dsdt() - Generate DSDT code for a device
+	 *
+	 * This is called to create the DSDT code. The method should write out
+	 * whatever ACPI code is needed by this device. It will end up in the
+	 * DSDT table.
+	 *
+	 * Note that this is called 'inject' because the output of calling this
+	 * method on all devices is injected into the DSDT, the bulk of which
+	 * is written in .asl files for the board.
+	 *
+	 * @dev: Device to write
+	 * @ctx: ACPI context to use
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*inject_dsdt)(const struct udevice *dev, struct acpi_ctx *ctx);
 };
 
 #define device_get_acpi_ops(dev)	((dev)->driver->acpi_ops)
@@ -141,6 +161,16 @@ int acpi_write_dev_tables(struct acpi_ctx *ctx);
  */
 int acpi_fill_ssdt(struct acpi_ctx *ctx);
 
+/**
+ * acpi_inject_dsdt() - Generate ACPI tables for DSDT
+ *
+ * This is called to create the DSDT code for all devices.
+ *
+ * @ctx: ACPI context to use
+ * @return 0 if OK, -ve on error
+ */
+int acpi_inject_dsdt(struct acpi_ctx *ctx);
+
 #endif /* __ACPI__ */
 
 #endif

test/dm/acpi.c

@@ -81,10 +81,24 @@ static int testacpi_fill_ssdt(const struct udevice *dev, struct acpi_ctx *ctx)
 	return 0;
 }
 
+static int testacpi_inject_dsdt(const struct udevice *dev, struct acpi_ctx *ctx)
+{
+	const char *data;
+
+	data = dev_read_string(dev, "acpi-dsdt-test-data");
+	if (data) {
+		while (*data)
+			acpigen_emit_byte(ctx, *data++);
+	}
+
+	return 0;
+}
+
 struct acpi_ops testacpi_ops = {
 	.get_name	= testacpi_get_name,
 	.write_tables	= testacpi_write_tables,
 	.fill_ssdt	= testacpi_fill_ssdt,
+	.inject_dsdt	= testacpi_inject_dsdt,
 };
 
 static const struct udevice_id testacpi_ids[] = {
@@ -441,3 +455,33 @@ static int dm_test_acpi_fill_ssdt(struct unit_test_state *uts)
 	return 0;
 }
 DM_TEST(dm_test_acpi_fill_ssdt, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);
+
+/* Test acpi_inject_dsdt() */
+static int dm_test_acpi_inject_dsdt(struct unit_test_state *uts)
+{
+	struct acpi_ctx ctx;
+	u8 *buf;
+
+	buf = malloc(BUF_SIZE);
+	ut_assertnonnull(buf);
+
+	ctx.current = buf;
+	buf[4] = 'z';	/* sentinel */
+	ut_assertok(acpi_inject_dsdt(&ctx));
+
+	/*
+	 * These values come from acpi-test's acpi-dsdt-test-data property.
+	 * There is no u-boot,acpi-dsdt-order so device-tree order is used.
+	 */
+	ut_asserteq('h', buf[0]);
+	ut_asserteq('i', buf[1]);
+
+	/* These values come from acpi-test's acpi-dsdt-test-data property */
+	ut_asserteq('j', buf[2]);
+	ut_asserteq('k', buf[3]);
+
+	ut_asserteq('z', buf[4]);
+
+	return 0;
+}
+DM_TEST(dm_test_acpi_inject_dsdt, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);