linux/drivers/of/Kconfig
Baoquan He 7e08baf6a8 of: make OF_EARLY_FLATTREE depend on HAS_IOMEM
On s390 systems (aka mainframes), it has classic channel devices for
networking and permanent storage that are currently even more common
than PCI devices. Hence it could have a fully functional s390 kernel
with CONFIG_PCI=n, then the relevant iomem mapping functions
[including ioremap(), devm_ioremap(), etc.] are not available.

In LKP error report at below on s390:
------
ld: kernel/dma/coherent.o: in function `dma_init_coherent_memory':
coherent.c:(.text+0x102): undefined reference to `memremap'
ld: coherent.c:(.text+0x226): undefined reference to `memunmap'
ld: kernel/dma/coherent.o: in function `dma_declare_coherent_memory':
coherent.c:(.text+0x8b8): undefined reference to `memunmap'
ld: kernel/dma/coherent.o: in function `dma_release_coherent_memory':
coherent.c:(.text+0x9aa): undefined reference to `memunmap'
------

In the config file, several Kconfig options are:
------
'# CONFIG_PCI is not set'
CONFIG_OF_EARLY_FLATTREE=y
CONFIG_DMA_DECLARE_COHERENT=y
------

So, enabling OF_EARLY_FLATTREE will select DMA_DECLARE_COHERENT
and cause above building errors even though they are not needed
because CONFIG_PCI is disabled.

Here let OF_EARLY_FLATTREE depend on HAS_IOMEM so that it won't
be built to cause compiling error if PCI is unset.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202306211329.ticOJCSv-lkp@intel.com/
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: devicetree@vger.kernel.org
Link: https://lore.kernel.org/r/20230707135852.24292-9-bhe@redhat.com
Signed-off-by: Rob Herring <robh@kernel.org>
2023-07-10 08:48:35 -06:00

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# SPDX-License-Identifier: GPL-2.0
config DTC
bool
menuconfig OF
bool "Device Tree and Open Firmware support"
help
This option enables the device tree infrastructure.
It is automatically selected by platforms that need it or can
be enabled manually for unittests, overlays or
compile-coverage.
if OF
config OF_UNITTEST
bool "Device Tree runtime unit tests"
depends on !SPARC
select IRQ_DOMAIN
select OF_EARLY_FLATTREE
select OF_RESOLVE
help
This option builds in test cases for the device tree infrastructure
that are executed once at boot time, and the results dumped to the
console.
This option should only be enabled for a development kernel. The tests
will taint the kernel with TAINT_TEST. The tests will cause ERROR and
WARNING messages to print on the console. The tests will cause stack
traces to print on the console. It is possible that the tests will
leave the devicetree in a corrupted state.
The unittest output will be verbose. Copy the output to a file
via capturing the console output or via the dmesg command. Process
this file with scripts/dtc/of_unittest_expect to reduce the
verbosity, test whether expected output is present, and to
summarize the results.
If unsure, say N here. This option is not safe to enable.
config OF_ALL_DTBS
bool "Build all Device Tree Blobs"
depends on COMPILE_TEST
select DTC
help
This option builds all possible Device Tree Blobs (DTBs) for the
current architecture.
If unsure, say N here, but this option is safe to enable.
config OF_FLATTREE
bool
select DTC
select LIBFDT
select CRC32
config OF_EARLY_FLATTREE
bool
select DMA_DECLARE_COHERENT if HAS_DMA && HAS_IOMEM
select OF_FLATTREE
config OF_PROMTREE
bool
config OF_KOBJ
def_bool SYSFS
# Hardly any platforms need this. It is safe to select, but only do so if you
# need it.
config OF_DYNAMIC
bool "Support for dynamic device trees" if OF_UNITTEST
select OF_KOBJ
help
On some platforms, the device tree can be manipulated at runtime.
While this option is selected automatically on such platforms, you
can enable it manually to improve device tree unit test coverage.
config OF_ADDRESS
def_bool y
depends on !SPARC && (HAS_IOMEM || UML)
config OF_IRQ
def_bool y
depends on !SPARC && IRQ_DOMAIN
config OF_RESERVED_MEM
def_bool OF_EARLY_FLATTREE
config OF_RESOLVE
bool
config OF_OVERLAY
bool "Device Tree overlays"
select OF_DYNAMIC
select OF_FLATTREE
select OF_RESOLVE
help
Overlays are a method to dynamically modify part of the kernel's
device tree with dynamically loaded data.
While this option is selected automatically when needed, you can
enable it manually to improve device tree unit test coverage.
config OF_NUMA
bool
endif # OF