[PATCH 13/15] microblaze: migrate to the generic rule for built-in DTB

From: Masahiro Yamada <masahiroy@kernel.org>
To: linux-kbuild@vger.kernel.org
Cc: linux-arch@vger.kernel.org, linux-snps-arc@lists.infradead.org,
	linux-kernel@vger.kernel.org, Michal Simek <monstr@monstr.eu>,
	Rob Herring <robh@kernel.org>,
	devicetree@vger.kernel.org, linux-mips@vger.kernel.org,
	linux-openrisc@vger.kernel.org, Dinh Nguyen <dinguyen@kernel.org>,
	Masahiro Yamada <masahiroy@kernel.org>
Subject: [PATCH 13/15] microblaze: migrate to the generic rule for built-in DTB
Date: Thu,  5 Sep 2024 08:47:49 +0900	[thread overview]
Message-ID: <20240904234803.698424-14-masahiroy@kernel.org> (raw)
In-Reply-To: <20240904234803.698424-1-masahiroy@kernel.org>

Select GENERIC_BUILTIN_DTB to use the generic rule to support built-in
DTB.

MicroBlaze is the only architecture that embeds the boot DTB into its
own section, __fdt_blob, and hard-codes the section size to 64kB.

All other architectures that support embedded DTBs use the
.dtb.init.rodata handled by include/asm-generic/vmlinux.lds.h.

For safety, arch/microblaze/boot/dts/system.dtb is still placed in the
__fdt_blob section, but removing the MicroBlaze-specific section should
be considered.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 arch/microblaze/Kbuild                | 1 -
 arch/microblaze/Kconfig               | 5 +++++
 arch/microblaze/boot/dts/Makefile     | 5 -----
 arch/microblaze/boot/dts/linked_dtb.S | 2 --
 arch/microblaze/kernel/vmlinux.lds.S  | 2 +-
 5 files changed, 6 insertions(+), 9 deletions(-)
 delete mode 100644 arch/microblaze/boot/dts/linked_dtb.S

diff --git a/arch/microblaze/Kbuild b/arch/microblaze/Kbuild
index 077a0b8e9615..70510389eb92 100644
--- a/arch/microblaze/Kbuild
+++ b/arch/microblaze/Kbuild
@@ -2,7 +2,6 @@
 obj-y			+= kernel/
 obj-y			+= mm/
 obj-$(CONFIG_PCI)	+= pci/
-obj-y			+= boot/dts/
 
 # for cleaning
 subdir- += boot
diff --git a/arch/microblaze/Kconfig b/arch/microblaze/Kconfig
index f18ec02ddeb2..4ed8ca89f0c9 100644
--- a/arch/microblaze/Kconfig
+++ b/arch/microblaze/Kconfig
@@ -10,6 +10,7 @@ config MICROBLAZE
 	select ARCH_MIGHT_HAVE_PC_PARPORT
 	select ARCH_WANT_IPC_PARSE_VERSION
 	select BUILDTIME_TABLE_SORT
+	select GENERIC_BUILTIN_DTB
 	select TIMER_OF
 	select CLONE_BACKWARDS3
 	select COMMON_CLK
@@ -47,6 +48,10 @@ config MICROBLAZE
 	select TRACE_IRQFLAGS_SUPPORT
 	select GENERIC_IRQ_MULTI_HANDLER
 
+config BUILTIN_DTB_NAME
+	string
+	default "system"
+
 # Endianness selection
 choice
 	prompt "Endianness selection"
diff --git a/arch/microblaze/boot/dts/Makefile b/arch/microblaze/boot/dts/Makefile
index b84e2cbb20ee..87c1d25ff096 100644
--- a/arch/microblaze/boot/dts/Makefile
+++ b/arch/microblaze/boot/dts/Makefile
@@ -4,11 +4,6 @@
 dtb-y := system.dtb
 
 ifneq ($(DTB),)
-obj-y += linked_dtb.o
-
-# Ensure system.dtb exists
-$(obj)/linked_dtb.o: $(obj)/system.dtb
-
 # Generate system.dtb from $(DTB).dtb
 ifneq ($(DTB),system)
 $(obj)/system.dtb: $(obj)/$(DTB).dtb
diff --git a/arch/microblaze/boot/dts/linked_dtb.S b/arch/microblaze/boot/dts/linked_dtb.S
deleted file mode 100644
index 23345af3721f..000000000000
--- a/arch/microblaze/boot/dts/linked_dtb.S
+++ /dev/null
@@ -1,2 +0,0 @@
-.section __fdt_blob,"a"
-.incbin "arch/microblaze/boot/dts/system.dtb"
diff --git a/arch/microblaze/kernel/vmlinux.lds.S b/arch/microblaze/kernel/vmlinux.lds.S
index ae50d3d04a7d..e86f9ca8e979 100644
--- a/arch/microblaze/kernel/vmlinux.lds.S
+++ b/arch/microblaze/kernel/vmlinux.lds.S
@@ -47,7 +47,7 @@ SECTIONS {
 	. = ALIGN (8) ;
 	__fdt_blob : AT(ADDR(__fdt_blob) - LOAD_OFFSET) {
 		_fdt_start = . ;		/* place for fdt blob */
-		*(__fdt_blob) ;			/* Any link-placed DTB */
+		*(.dtb.init.rodata) ;		/* Any link-placed DTB */
 	        . = _fdt_start + 0x10000;	/* Pad up to 64kbyte */
 		_fdt_end = . ;
 	}
-- 
2.43.0

