dm: core: Add basic ACPI support

ACPI (Advanced Configuration and Power Interface) is a standard for
specifying information about a platform. It is a little like device
tree but the bindings are part of the specification and it supports an
interpreted bytecode language.

Driver model does not use ACPI for U-Boot's configuration, but it is
convenient to have it support generation of ACPI tables for passing to
Linux, etc.

As a starting point, add an optional set of ACPI operations to each
device. Initially only a single operation is available, to obtain the
ACPI name for the device. More operations are added later.

Enable ACPI for sandbox to ensure build coverage and so that we can add
tests.

Signed-off-by: Simon Glass <[email protected]>
Reviewed-by: Bin Meng <[email protected]>
Reviewed-by: Wolfgang Wallner <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>

3 files changed, 43 insertions, 0 deletions

diff --git a/drivers/core/Kconfig b/drivers/core/Kconfig
index 3b95b5387b9..a3b03993423 100644
--- a/drivers/core/Kconfig
+++ b/drivers/core/Kconfig
@@ -261,4 +261,13 @@ config DM_DEV_READ_INLINE
 	bool
 	default y if !OF_LIVE
 
+config ACPIGEN
+	bool "Support ACPI table generation in driver model"
+	default y if SANDBOX || GENERATE_ACPI_TABLE
+	help
+	  This option enables generation of ACPI tables using driver-model
+	  devices. It adds a new operation struct to each driver, to support
+	  things like generating device-specific tables and returning the ACPI
+	  name of a device.
+
 endmenu
diff --git a/drivers/core/Makefile b/drivers/core/Makefile
index bce7467da1d..c707026a3a0 100644
--- a/drivers/core/Makefile
+++ b/drivers/core/Makefile
@@ -3,6 +3,7 @@
 # Copyright (c) 2013 Google, Inc
 
 obj-y	+= device.o fdtaddr.o lists.o root.o uclass.o util.o
+obj-$(CONFIG_$(SPL_TPL_)ACPIGEN) += acpi.o
 obj-$(CONFIG_DEVRES) += devres.o
 obj-$(CONFIG_$(SPL_)DM_DEVICE_REMOVE)	+= device-remove.o
 obj-$(CONFIG_$(SPL_)SIMPLE_BUS)	+= simple-bus.o
diff --git a/drivers/core/acpi.c b/drivers/core/acpi.c
new file mode 100644
index 00000000000..ba50d688fef
--- /dev/null
+++ b/drivers/core/acpi.c
@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Core driver model support for ACPI table generation
+ *
+ * Copyright 2019 Google LLC
+ * Written by Simon Glass <[email protected]>
+ */
+
+#define LOG_CATEOGRY	LOGC_ACPI
+
+#include <common.h>
+#include <dm.h>
+#include <dm/acpi.h>
+#include <dm/root.h>
+
+int acpi_copy_name(char *out_name, const char *name)
+{
+	strncpy(out_name, name, ACPI_NAME_LEN);
+	out_name[ACPI_NAME_LEN] = '\0';
+
+	return 0;
+}
+
+int acpi_get_name(const struct udevice *dev, char *out_name)
+{
+	struct acpi_ops *aops;
+
+	aops = device_get_acpi_ops(dev);
+	if (aops && aops->get_name)
+		return aops->get_name(dev, out_name);
+
+	return -ENOSYS;
+}