[PATCH V2 XRT Alveo Infrastructure 4/9] of: create empty of root
From: Lizhi Hou <hidden>
Date: 2021-11-19 22:24:59
Also in:
linux-fpga, lkml
Subsystem:
open firmware and flattened device tree, the rest · Maintainers:
Rob Herring, Saravana Kannan, Linus Torvalds
When OF_FLATTREE is selected and there is not a device tree, create an empty device tree root node. of/unittest.c code is referenced. Signed-off-by: Sonal Santan <redacted> Signed-off-by: Max Zhen <redacted> Signed-off-by: Lizhi Hou <redacted> --- drivers/of/Makefile | 2 +- drivers/of/fdt.c | 20 ++++++++++++++++++++ drivers/of/fdt_default.dts | 5 +++++ drivers/of/of_private.h | 5 +++++ 4 files changed, 31 insertions(+), 1 deletion(-) create mode 100644 drivers/of/fdt_default.dts
diff --git a/drivers/of/Makefile b/drivers/of/Makefile
index c13b982084a3..815f5220465b 100644
--- a/drivers/of/Makefile
+++ b/drivers/of/Makefile@@ -2,7 +2,7 @@ obj-y = base.o device.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 fdt_default.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/fdt.c b/drivers/of/fdt.c
index d64445e43ceb..3d6e4543419e 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c@@ -481,6 +481,26 @@ void *of_fdt_unflatten_tree(const unsigned long *blob, } EXPORT_SYMBOL_GPL(of_fdt_unflatten_tree); +static int __init of_fdt_root_init(void) +{ + struct device_node *np; + + if (of_root) + return 0; + + if (!of_fdt_unflatten_tree((const unsigned long *)__dtb_fdt_default_begin, + NULL, &of_root)) { + pr_warn("%s: unflatten default tree failed\n", __func__); + return -ENODATA; + } + + for_each_of_allnodes(np) + __of_attach_node_sysfs(np); + + return 0; +} +late_initcall(of_fdt_root_init); + /* Everything below here references initial_boot_params directly. */ int __initdata dt_root_addr_cells; int __initdata dt_root_size_cells;
diff --git a/drivers/of/fdt_default.dts b/drivers/of/fdt_default.dts
new file mode 100644
index 000000000000..d1f12a76dfc6
--- /dev/null
+++ b/drivers/of/fdt_default.dts@@ -0,0 +1,5 @@ +// SPDX-License-Identifier: GPL-2.0 +/dts-v1/; + +/ { +};
diff --git a/drivers/of/of_private.h b/drivers/of/of_private.h
index 631489f7f8c0..47c6bb47ef25 100644
--- a/drivers/of/of_private.h
+++ b/drivers/of/of_private.h@@ -41,6 +41,11 @@ extern struct mutex of_mutex; extern struct list_head aliases_lookup; extern struct kset *of_kset; +#if defined(CONFIG_OF_FLATTREE) +extern u8 __dtb_fdt_default_begin[]; +extern u8 __dtb_fdt_default_end[]; +#endif + #if defined(CONFIG_OF_DYNAMIC) extern int of_property_notify(int action, struct device_node *np, struct property *prop, struct property *old_prop);
--
2.27.0