[PATCH v2 32/76] ARC: [DeviceTree] Basic support
Vineet Gupta
Vineet.Gupta1 at synopsys.com
Fri Jan 18 23:24:46 EST 2013
This is minimal infrastructure needed for devicetree work.
It uses an a sample "skeleton" devicetree - embedded in kernel image -
to print the board, manufacturer by parsing the top-level "compatible"
string.
As of now we don't need any additional "board" specific "machine_desc".
TODO: support interpreting the command line as boot-loader passed dtb
Signed-off-by: Vineet Gupta <vgupta at synopsys.com>
Cc: Arnd Bergmann <arnd at arndb.de>
Cc: Grant Likely <grant.likely at secretlab.ca>
Cc: devicetree-discuss at lists.ozlabs.org
Cc: Rob Herring <rob.herring at calxeda.com>
---
arch/arc/Kconfig | 9 +++++
arch/arc/Makefile | 9 +++++
arch/arc/boot/dtb/Makefile | 22 ++++++++++++
arch/arc/boot/dts/skeleton.dts | 10 ++++++
arch/arc/boot/dts/skeleton.dtsi | 21 ++++++++++++
arch/arc/include/asm/prom.h | 15 ++++++++
arch/arc/include/asm/sections.h | 1 +
arch/arc/kernel/Makefile | 2 +
arch/arc/kernel/devtree.c | 69 +++++++++++++++++++++++++++++++++++++++
arch/arc/kernel/setup.c | 9 +++++
arch/arc/mm/init.c | 13 +++++++
11 files changed, 180 insertions(+), 0 deletions(-)
create mode 100644 arch/arc/boot/dtb/Makefile
create mode 100644 arch/arc/boot/dts/skeleton.dts
create mode 100644 arch/arc/boot/dts/skeleton.dtsi
create mode 100644 arch/arc/include/asm/prom.h
create mode 100644 arch/arc/kernel/devtree.c
diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index d457a83..5175cf7 100644
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -21,7 +21,10 @@ config ARC
select GENERIC_SMP_IDLE_THREAD
select HAVE_GENERIC_HARDIRQS
select HOTPLUG if !INITRAMFS_SOURCE=""
+ select IRQ_DOMAIN
select MODULES_USE_ELF_RELA
+ select OF
+ select OF_EARLY_FLATTREE
config SCHED_OMIT_FRAME_POINTER
def_bool y
@@ -316,6 +319,12 @@ config CMDLINE_UBOOT
to it. kernel startup code will copy the string into cmdline buffer
and also append CONFIG_CMDLINE.
+config ARC_BUILTIN_DTB_NAME
+ string "Built in DTB"
+ help
+ Set the name of the DTB to embed in the vmlinux binary
+ Leaving it blank selects the minimal "skeleton" dtb
+
source "kernel/Kconfig.preempt"
endmenu # "ARC Architecture Configuration"
diff --git a/arch/arc/Makefile b/arch/arc/Makefile
index 4d52a3b..d697e9c 100644
--- a/arch/arc/Makefile
+++ b/arch/arc/Makefile
@@ -83,6 +83,9 @@ head-y := arch/arc/kernel/head.o
# See arch/arc/Kbuild for content of core part of the kernel
core-y += arch/arc/
+# w/o this dtb won't embed into kernel binary
+core-y += arch/arc/boot/dtb/
+
# w/o this ifneq, make ARCH=arc clean was crapping out
ifneq ($(platform-y),)
core-y += arch/arc/plat-$(PLATFORM)/
@@ -101,6 +104,12 @@ bootpImage: vmlinux
uImage: vmlinux
$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
+%.dtb %.dtb.S %.dtb.o:
+ $(Q)$(MAKE) $(build)=$(boot)/dtb $(boot)/dtb/$@
+
+dtbs:
+ $(Q)$(MAKE) $(build)=$(boot)/dtb $(boot)/dtb/$@
+
archclean:
$(Q)$(MAKE) $(clean)=$(boot)
diff --git a/arch/arc/boot/dtb/Makefile b/arch/arc/boot/dtb/Makefile
new file mode 100644
index 0000000..825af84
--- /dev/null
+++ b/arch/arc/boot/dtb/Makefile
@@ -0,0 +1,22 @@
+ifeq ($(CONFIG_OF),y)
+
+dtb-y += skeleton.dtb
+
+# Built-in dtb
+builtindtb-y := skeleton
+
+ifneq ($(CONFIG_ARC_BUILTIN_DTB_NAME),"")
+ builtindtb-y := $(CONFIG_ARC_BUILTIN_DTB_NAME)
+endif
+
+obj-y += $(patsubst "%",%,$(builtindtb-y)).dtb.o
+
+clean-files += $(obj)/$(dtb-y) $(obj)/*.dtb.S $(obj)/*.dtb.o
+
+# Rule to build device tree blobs
+$(obj)/%.dtb: $(src)/../dts/%.dts FORCE
+ $(call if_changed_dep,dtc)
+
+$(obj)/dtbs: $(addprefix $(obj)/, $(dtb-y))
+
+endif
diff --git a/arch/arc/boot/dts/skeleton.dts b/arch/arc/boot/dts/skeleton.dts
new file mode 100644
index 0000000..25a84fb
--- /dev/null
+++ b/arch/arc/boot/dts/skeleton.dts
@@ -0,0 +1,10 @@
+/*
+ * Copyright (C) 2012 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+/dts-v1/;
+
+/include/ "skeleton.dtsi"
diff --git a/arch/arc/boot/dts/skeleton.dtsi b/arch/arc/boot/dts/skeleton.dtsi
new file mode 100644
index 0000000..f6a457a
--- /dev/null
+++ b/arch/arc/boot/dts/skeleton.dtsi
@@ -0,0 +1,21 @@
+/*
+ * Copyright (C) 2012 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+/*
+ * Skeleton device tree; the bare minimum needed to boot; just include and
+ * add a compatible value.
+ */
+
+/ {
+ compatible = "snps,arc-angel4", "snps,arc-ml509";
+ #address-cells = <1>;
+ #size-cells = <1>;
+ chosen { };
+ aliases { };
+ memory { device_type = "memory"; reg = <0 0>; };
+};
diff --git a/arch/arc/include/asm/prom.h b/arch/arc/include/asm/prom.h
new file mode 100644
index 0000000..f54489b
--- /dev/null
+++ b/arch/arc/include/asm/prom.h
@@ -0,0 +1,15 @@
+/*
+ * Copyright (C) 2012 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _ASM_ARC_PROM_H_
+#define _ASM_ARC_PROM_H_
+
+#define HAVE_ARCH_DEVTREE_FIXUPS
+extern int __init setup_machine_fdt(void *dt);
+
+#endif
diff --git a/arch/arc/include/asm/sections.h b/arch/arc/include/asm/sections.h
index fc15f2e..6fc1159 100644
--- a/arch/arc/include/asm/sections.h
+++ b/arch/arc/include/asm/sections.h
@@ -13,5 +13,6 @@
extern char _int_vec_base_lds[];
extern char __arc_dccm_base[];
+extern char __dtb_start[];
#endif
diff --git a/arch/arc/kernel/Makefile b/arch/arc/kernel/Makefile
index ae140e5..5fefb7d 100644
--- a/arch/arc/kernel/Makefile
+++ b/arch/arc/kernel/Makefile
@@ -8,6 +8,8 @@
obj-y := arcksyms.o setup.o irq.o time.o reset.o ptrace.o entry.o process.o \
signal.o traps.o sys.o troubleshoot.o stacktrace.o clk.o
+obj-$(CONFIG_OF) += devtree.o
+
obj-$(CONFIG_ARC_FPU_SAVE_RESTORE) += fpu.o
CFLAGS_fpu.o += -mdpfp
diff --git a/arch/arc/kernel/devtree.c b/arch/arc/kernel/devtree.c
new file mode 100644
index 0000000..021293d
--- /dev/null
+++ b/arch/arc/kernel/devtree.c
@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2012 Synopsys, Inc. (www.synopsys.com)
+ *
+ * Based on highly stipped down version of METAG
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+
+#include <linux/init.h>
+#include <linux/export.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/reboot.h>
+#include <linux/bootmem.h>
+#include <linux/of.h>
+#include <linux/of_fdt.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <asm/prom.h>
+
+/* called from unflatten_device_tree() to bootstrap devicetree itself */
+void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align)
+{
+ return alloc_bootmem_align(size, align);
+}
+
+/**
+ * setup_machine_fdt - Machine setup when an dtb was passed to the kernel
+ * @dt: virtual address pointer to dt blob
+ *
+ * If a dtb was passed to the kernel, then use it to choose the correct
+ * machine_desc and to setup the system.
+ */
+int __init setup_machine_fdt(void *dt)
+{
+ struct boot_param_header *devtree = dt;
+ unsigned long dt_root;
+ char *model, *compat;
+ char manufacturer[16];
+
+ /* check device tree validity */
+ if (be32_to_cpu(devtree->magic) != OF_DT_HEADER)
+ return 1;
+
+ /* Search the mdescs for the 'best' compatible value match */
+ initial_boot_params = devtree;
+ dt_root = of_get_flat_dt_root();
+
+ /* compat = "<manufacturer>,<model>" */
+ compat = of_get_flat_dt_prop(dt_root, "compatible", NULL);
+ if (!compat)
+ compat = "<unknown>";
+
+ model = strchr(compat, ',');
+ if (model)
+ model++;
+
+ strlcpy(manufacturer, compat, model ? model - compat : strlen(compat));
+
+ pr_info("Board \"%s\" from %s (Manufacturer)\n", model, manufacturer);
+
+ /* Retrieve various information from the /chosen node */
+ of_scan_flat_dt(early_init_dt_scan_chosen, boot_command_line);
+
+ return 0;
+}
diff --git a/arch/arc/kernel/setup.c b/arch/arc/kernel/setup.c
index 82ac206..27aebd6 100644
--- a/arch/arc/kernel/setup.c
+++ b/arch/arc/kernel/setup.c
@@ -13,6 +13,8 @@
#include <linux/console.h>
#include <linux/module.h>
#include <linux/cpu.h>
+#include <linux/of_fdt.h>
+#include <asm/sections.h>
#include <asm/arcregs.h>
#include <asm/tlb.h>
#include <asm/cache.h>
@@ -20,6 +22,7 @@
#include <asm/page.h>
#include <asm/irq.h>
#include <asm/arcregs.h>
+#include <asm/prom.h>
#define FIX_PTR(x) __asm__ __volatile__(";" : "+r"(x))
@@ -57,6 +60,8 @@ void __init __attribute__((weak)) arc_platform_early_init(void)
void __init setup_arch(char **cmdline_p)
{
+ int rc;
+
#ifdef CONFIG_CMDLINE_UBOOT
/* Make sure that a whitespace is inserted before */
strlcat(command_line, " ", sizeof(command_line));
@@ -71,6 +76,8 @@ void __init setup_arch(char **cmdline_p)
strlcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
*cmdline_p = command_line;
+ rc = setup_machine_fdt(__dtb_start);
+
/* To force early parsing of things like mem=xxx */
parse_early_param();
@@ -81,6 +88,8 @@ void __init setup_arch(char **cmdline_p)
setup_arch_memory();
+ unflatten_device_tree();
+
/* Can be issue if someone passes cmd line arg "ro"
* But that is unlikely so keeping it as it is
*/
diff --git a/arch/arc/mm/init.c b/arch/arc/mm/init.c
index 9897847..1087a97 100644
--- a/arch/arc/mm/init.c
+++ b/arch/arc/mm/init.c
@@ -38,6 +38,11 @@ static int __init setup_mem_sz(char *str)
}
early_param("mem", setup_mem_sz);
+void __init early_init_dt_add_memory_arch(u64 base, u64 size)
+{
+ pr_err("%s(%llx, %llx)\n", __func__, base, size);
+}
+
/*
* First memory setup routine called from setup_arch()
* 1. setup swapper's mm @init_mm
@@ -181,3 +186,11 @@ void __init free_initrd_mem(unsigned long start, unsigned long end)
free_init_pages("initrd memory", start, end);
}
#endif
+
+#ifdef CONFIG_OF_FLATTREE
+void __init early_init_dt_setup_initrd_arch(unsigned long start,
+ unsigned long end)
+{
+ pr_err("%s(%lx, %lx)\n", __func__, start, end);
+}
+#endif /* CONFIG_OF_FLATTREE */
--
1.7.4.1
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