ARM: 7506/1: allow for ATAGS to be configured out when DT support is selected

Now that ATAGS support is well contained, we can easily remove it from
the kernel build if so desired.  It has to explicitly be disabled, and
only when DT support is selected.

Note: disabling kernel ATAGS support does not prevent the usage of
CONFIG_ARM_ATAG_DTB_COMPAT.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

2 files changed, 14 insertions, 2 deletions

diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index 086c9d3bc360..79e346a5d78b 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -15,10 +15,12 @@ CFLAGS_REMOVE_return_address.o = -pg
 
 # Object file lists.
 
-obj-y           := atags_parse.o elf.o entry-armv.o entry-common.o irq.o opcodes.o \
+obj-y           := elf.o entry-armv.o entry-common.o irq.o opcodes.o \
                    process.o ptrace.o return_address.o sched_clock.o \
                    setup.o signal.o stacktrace.o sys_arm.o time.o traps.o
 
+obj-$(CONFIG_ATAGS)             += atags_parse.o
+obj-$(CONFIG_ATAGS_PROC)        += atags_proc.o
 obj-$(CONFIG_DEPRECATED_PARAM_STRUCT) += atags_compat.o
 
 obj-$(CONFIG_LEDS)              += leds.o
@@ -52,7 +54,6 @@ test-kprobes-objs		+= kprobes-test-thumb.o
 else
 test-kprobes-objs               += kprobes-test-arm.o
 endif
-obj-$(CONFIG_ATAGS_PROC)        += atags_proc.o
 obj-$(CONFIG_OABI_COMPAT)       += sys_oabi-compat.o
 obj-$(CONFIG_ARM_THUMBEE)       += thumbee.o
 obj-$(CONFIG_KGDB)              += kgdb.o
diff --git a/arch/arm/kernel/atags.h b/arch/arm/kernel/atags.h
index a888fdd381b5..9edc9692332d 100644
--- a/arch/arm/kernel/atags.h
+++ b/arch/arm/kernel/atags.h
@@ -5,4 +5,15 @@ static inline void save_atags(struct tag *tags) { }
 #endif
 
 void convert_to_tag_list(struct tag *tags);
+
+#ifdef CONFIG_ATAGS
 struct machine_desc *setup_machine_tags(phys_addr_t __atags_pointer, unsigned int machine_nr);
+#else
+static inline struct machine_desc *
+setup_machine_tags(phys_addr_t __atags_pointer, unsigned int machine_nr)
+{
+        early_print("no ATAGS support: can't continue\n");
+        while (true);
+        unreachable();
+}
+#endif