During the upstream progress of those DT-based drivers, DT properties are changed a lot so very different from those in existing bootloaders. It is inevitably that some existing systems do not provide a standard, canonical device tree to the kernel at boot time. So let's provide a device tree table in the kernel, keyed by the dts filename, containing the relevant DTBs. We can use the built-in dts files as references. Each SoC has only one built-in dts file which describes all possible device information of that SoC, so the dts files are good examples during development. And as a reference, our built-in dts file only enables the most basic bootable combinations (so it is generic enough), acts as an alternative in case the dts in the bootloader is unexpected. Signed-off-by: Binbin Zhou <zhoubinbin@xxxxxxxxxxx> Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx> --- arch/loongarch/Kbuild | 1 + arch/loongarch/Kconfig | 18 ++++++++++++++++++ arch/loongarch/Makefile | 3 ++- arch/loongarch/boot/dts/Makefile | 3 +-- arch/loongarch/kernel/setup.c | 12 +++++++++--- 5 files changed, 31 insertions(+), 6 deletions(-) diff --git a/arch/loongarch/Kbuild b/arch/loongarch/Kbuild index beb8499dd8ed..bfa21465d83a 100644 --- a/arch/loongarch/Kbuild +++ b/arch/loongarch/Kbuild @@ -4,6 +4,7 @@ obj-y += net/ obj-y += vdso/ obj-$(CONFIG_KVM) += kvm/ +obj-$(CONFIG_BUILTIN_DTB) += boot/dts/ # for cleaning subdir- += boot diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig index ee123820a476..dd23ed31c12f 100644 --- a/arch/loongarch/Kconfig +++ b/arch/loongarch/Kconfig @@ -374,6 +374,24 @@ config CMDLINE_FORCE endchoice +config BUILTIN_DTB + bool "Enable built-in dtb in kernel" + depends on OF + help + Some existing systems do not provide a canonical device tree to + the kernel at boot time. Let's provide a device tree table in the + kernel, keyed by the dts filename, containing the relevant DTBs. + + Built-in DTBs are generic enough and can be used as references. + +config BUILTIN_DTB_NAME + string "Source file for built-in dtb" + depends on BUILTIN_DTB + help + Base name (without suffix, relative to arch/loongarch/boot/dts/) + for the DTS file that will be used to produce the DTB linked into + the kernel. + config DMI bool "Enable DMI scanning" select DMI_SCAN_MACHINE_NON_EFI_FALLBACK diff --git a/arch/loongarch/Makefile b/arch/loongarch/Makefile index 4ba8d67ddb09..2ef3ff097f9a 100644 --- a/arch/loongarch/Makefile +++ b/arch/loongarch/Makefile @@ -6,6 +6,7 @@ boot := arch/loongarch/boot KBUILD_DEFCONFIG := loongson3_defconfig +KBUILD_DTBS := dtbs image-name-y := vmlinux image-name-$(CONFIG_EFI_ZBOOT) := vmlinuz @@ -141,7 +142,7 @@ endif vdso-install-y += arch/loongarch/vdso/vdso.so.dbg -all: $(notdir $(KBUILD_IMAGE)) +all: $(notdir $(KBUILD_IMAGE)) $(KBUILD_DTBS) vmlinuz.efi: vmlinux.efi diff --git a/arch/loongarch/boot/dts/Makefile b/arch/loongarch/boot/dts/Makefile index 5f1f55e911ad..1e24cdb5180a 100644 --- a/arch/loongarch/boot/dts/Makefile +++ b/arch/loongarch/boot/dts/Makefile @@ -1,4 +1,3 @@ # SPDX-License-Identifier: GPL-2.0-only -dtstree := $(srctree)/$(src) -dtb-y := $(patsubst $(dtstree)/%.dts,%.dtb, $(wildcard $(dtstree)/*.dts)) +obj-$(CONFIG_BUILTIN_DTB) += $(addsuffix .dtb.o, $(CONFIG_BUILTIN_DTB_NAME)) diff --git a/arch/loongarch/kernel/setup.c b/arch/loongarch/kernel/setup.c index d183a745fb85..15d366b8407c 100644 --- a/arch/loongarch/kernel/setup.c +++ b/arch/loongarch/kernel/setup.c @@ -295,8 +295,12 @@ static void __init fdt_setup(void) if (acpi_os_get_root_pointer()) return; - /* Look for a device tree configuration table entry */ - fdt_pointer = efi_fdt_pointer(); + /* Prefer to use built-in dtb, checking its legality first. */ + if (!fdt_check_header(__dtb_start)) + fdt_pointer = __dtb_start; + else + fdt_pointer = efi_fdt_pointer(); /* Fallback to firmware dtb */ + if (!fdt_pointer || fdt_check_header(fdt_pointer)) return; @@ -330,7 +334,9 @@ static void __init bootcmdline_init(char **cmdline_p) if (boot_command_line[0]) strlcat(boot_command_line, " ", COMMAND_LINE_SIZE); - strlcat(boot_command_line, init_command_line, COMMAND_LINE_SIZE); + if (!strstr(boot_command_line, init_command_line)) + strlcat(boot_command_line, init_command_line, COMMAND_LINE_SIZE); + goto out; } #endif -- 2.39.3
