Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751898AbaKGLaZ (ORCPT ); Fri, 7 Nov 2014 06:30:25 -0500 Received: from dotsec.net ([62.75.224.215]:48210 "EHLO styx.dotsec.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751325AbaKGLaX (ORCPT ); Fri, 7 Nov 2014 06:30:23 -0500 From: Alban Bedel To: devicetree@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Rob Herring , Grant Likely Subject: [PATCH] OF: Add support for built in FDT blob Date: Fri, 7 Nov 2014 12:14:09 +0100 Message-Id: <1415358849-25879-1-git-send-email-albeu@free.fr> X-Mailer: git-send-email 2.0.0 X-SA-Score: -1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Allow embedding an FDT blob in the kernel image, this is mostly useful to run new kernels on boards with old bootloaders. Signed-off-by: Alban Bedel --- drivers/of/Kconfig | 16 ++++++++++++++++ drivers/of/Makefile | 8 ++++++++ drivers/of/fdt.c | 8 ++++++++ drivers/of/fdt_blob.S | 17 +++++++++++++++++ 4 files changed, 49 insertions(+) create mode 100644 drivers/of/fdt_blob.S diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig index 1a13f5b..97c5d18 100644 --- a/drivers/of/Kconfig +++ b/drivers/of/Kconfig @@ -83,4 +83,20 @@ config OF_RESERVED_MEM config OF_RESOLVE bool +config OF_BUILTIN_FDT + bool "Include a FDT blob in the kernel" + help + Include a FDT blob in the kernel to use as default when + no blob has been passed by the bootloader. This is useful + to use devicetree on boards with old bootloaders. + + If unsure, say N. + +config OF_BUILTIN_FDT_BLOB + string "FDT Blob name" + depends on OF_BUILTIN_FDT + help + Name of the FDT blob to build in the kernel, from one of the + dtbs available for the current platform. + endmenu # OF diff --git a/drivers/of/Makefile b/drivers/of/Makefile index ca9209c..b96c6e9 100644 --- a/drivers/of/Makefile +++ b/drivers/of/Makefile @@ -14,6 +14,14 @@ obj-$(CONFIG_OF_PCI_IRQ) += of_pci_irq.o obj-$(CONFIG_OF_MTD) += of_mtd.o obj-$(CONFIG_OF_RESERVED_MEM) += of_reserved_mem.o obj-$(CONFIG_OF_RESOLVE) += resolver.o +obj-$(CONFIG_OF_BUILTIN_FDT) += fdt_blob.o CFLAGS_fdt.o = -I$(src)/../../scripts/dtc/libfdt CFLAGS_fdt_address.o = -I$(src)/../../scripts/dtc/libfdt + +# The FDT blob to include +FDT_BLOB := arch/$(ARCH)/boot/dts/$(CONFIG_OF_BUILTIN_FDT_BLOB:"%"=%).dtb +# Undefine ARCH to avoid breaking the FDT path +AFLAGS_fdt_blob.o += -U$(ARCH) -DFDT_BLOB=$(FDT_BLOB) +# This dependency can't be automatically tracked +$(obj)/fdt_blob.o: $(obj)/../../$(FDT_BLOB) diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c index d1ffca8..ffb86a7 100644 --- a/drivers/of/fdt.c +++ b/drivers/of/fdt.c @@ -26,6 +26,9 @@ #include /* for COMMAND_LINE_SIZE */ #include +extern char __fdt_blob_start[]; +extern unsigned long __fdt_blob_size; + /* * of_fdt_limit_memory - limit the number of regions in the /memory node * @limit: maximum entries @@ -1064,6 +1067,11 @@ void __init unflatten_and_copy_device_tree(void) int size; void *dt; +#ifdef CONFIG_OF_BUILTIN_FDT + if (!initial_boot_params && __fdt_blob_size > 0) + initial_boot_params = __fdt_blob_start; +#endif + if (!initial_boot_params) { pr_warn("No valid device tree found, continuing without\n"); return; diff --git a/drivers/of/fdt_blob.S b/drivers/of/fdt_blob.S new file mode 100644 index 0000000..fcaa2aa --- /dev/null +++ b/drivers/of/fdt_blob.S @@ -0,0 +1,17 @@ +#include +#include + +.align 4 +.section .init.fdt_blob,"a" +.globl VMLINUX_SYMBOL(__fdt_blob_start) +VMLINUX_SYMBOL(__fdt_blob_start): +.incbin __stringify(FDT_BLOB) +__fdt_blob_end: +.section .init.fdt_blob.info,"a" +.globl VMLINUX_SYMBOL(__fdt_blob_size) +VMLINUX_SYMBOL(__fdt_blob_size): +#ifdef CONFIG_64BIT + .quad __fdt_blob_end - __fdt_blob_start +#else + .long __fdt_blob_end - __fdt_blob_start +#endif -- 2.0.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/