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-rw-r--r--drivers/of/Kconfig5
-rw-r--r--drivers/of/Makefile2
-rw-r--r--drivers/of/empty_root.dts6
-rw-r--r--drivers/of/fdt.c32
-rw-r--r--drivers/of/platform.c3
5 files changed, 40 insertions, 8 deletions
diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
index da9826accb1b..d738fbad9c36 100644
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -14,9 +14,8 @@ if OF
config OF_UNITTEST
bool "Device Tree runtime unit tests"
- depends on !SPARC
+ depends on OF_EARLY_FLATTREE
select IRQ_DOMAIN
- select OF_EARLY_FLATTREE
select OF_RESOLVE
help
This option builds in test cases for the device tree infrastructure
@@ -54,7 +53,7 @@ config OF_FLATTREE
select CRC32
config OF_EARLY_FLATTREE
- bool
+ def_bool OF && !(SPARC || ALPHA || HEXAGON || M68K || PARISC || S390)
select DMA_DECLARE_COHERENT if HAS_DMA && HAS_IOMEM
select OF_FLATTREE
diff --git a/drivers/of/Makefile b/drivers/of/Makefile
index eff624854575..df305348d1cb 100644
--- a/drivers/of/Makefile
+++ b/drivers/of/Makefile
@@ -2,7 +2,7 @@
obj-y = base.o cpu.o device.o module.o platform.o property.o
obj-$(CONFIG_OF_KOBJ) += kobj.o
obj-$(CONFIG_OF_DYNAMIC) += dynamic.o
-obj-$(CONFIG_OF_FLATTREE) += fdt.o
+obj-$(CONFIG_OF_FLATTREE) += fdt.o empty_root.dtb.o
obj-$(CONFIG_OF_EARLY_FLATTREE) += fdt_address.o
obj-$(CONFIG_OF_PROMTREE) += pdt.o
obj-$(CONFIG_OF_ADDRESS) += address.o
diff --git a/drivers/of/empty_root.dts b/drivers/of/empty_root.dts
new file mode 100644
index 000000000000..cf9e97a60f48
--- /dev/null
+++ b/drivers/of/empty_root.dts
@@ -0,0 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/dts-v1/;
+
+/ {
+
+};
diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index dfeba8b8ce94..e5a385285149 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -8,6 +8,7 @@
#define pr_fmt(fmt) "OF: fdt: " fmt
+#include <linux/acpi.h>
#include <linux/crash_dump.h>
#include <linux/crc32.h>
#include <linux/kernel.h>
@@ -33,6 +34,13 @@
#include "of_private.h"
/*
+ * __dtb_empty_root_begin[] and __dtb_empty_root_end[] magically created by
+ * cmd_dt_S_dtb in scripts/Makefile.lib
+ */
+extern uint8_t __dtb_empty_root_begin[];
+extern uint8_t __dtb_empty_root_end[];
+
+/*
* of_fdt_limit_memory - limit the number of regions in the /memory node
* @limit: maximum entries
*
@@ -1343,7 +1351,29 @@ static void *__init copy_device_tree(void *fdt)
*/
void __init unflatten_device_tree(void)
{
- __unflatten_device_tree(initial_boot_params, NULL, &of_root,
+ void *fdt = initial_boot_params;
+
+ /* Don't use the bootloader provided DTB if ACPI is enabled */
+ if (!acpi_disabled)
+ fdt = NULL;
+
+ /*
+ * Populate an empty root node when ACPI is enabled or bootloader
+ * doesn't provide one.
+ */
+ if (!fdt) {
+ fdt = (void *) __dtb_empty_root_begin;
+ /* fdt_totalsize() will be used for copy size */
+ if (fdt_totalsize(fdt) >
+ __dtb_empty_root_end - __dtb_empty_root_begin) {
+ pr_err("invalid size in dtb_empty_root\n");
+ return;
+ }
+ of_fdt_crc32 = crc32_be(~0, fdt, fdt_totalsize(fdt));
+ fdt = copy_device_tree(fdt);
+ }
+
+ __unflatten_device_tree(fdt, NULL, &of_root,
early_init_dt_alloc_memory_arch, false);
/* Get pointer to "/chosen" and "/aliases" nodes for use everywhere */
diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index ba964df6b6db..389d4ea6bfc1 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -512,9 +512,6 @@ static int __init of_platform_default_populate_init(void)
device_links_supplier_sync_state_pause();
- if (!of_have_populated_dt())
- return -ENODEV;
-
if (IS_ENABLED(CONFIG_PPC)) {
struct device_node *boot_display = NULL;
struct platform_device *dev;