Re: ERROR: modpost: "gpmc_omap_get_nand_ops" [drivers/mtd/nand/raw/omap2_nand.ko] undefined!

[Roger Quadros <rogerq@kernel.org>]

Hi Krzysztof,

On 17/01/2022 15:08, Krzysztof Kozlowski wrote:
> On 17/01/2022 13:35, Roger Quadros wrote:
>> Hi,
>>
>> On 17/01/2022 12:51, kernel test robot wrote:
>>> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
>>> head:   0c947b893d69231a9add855939da7c66237ab44f
>>> commit: dbcb124acebd8148e9e858a231f1798956dd3ca6 mtd: rawnand: omap2: Select GPMC device driver for ARCH_K3
>>> date:   4 weeks ago
>>> config: arm64-randconfig-r001-20220117 (https://download.01.org/0day-ci/archive/20220117/202201171805.5HeoR4rS-lkp@intel.com/config)
>>> compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 5f782d25a742302d25ef3c8b84b54f7483c2deb9)
>>> reproduce (this is a W=1 build):
>>>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>>>         chmod +x ~/bin/make.cross
>>>         # install arm64 cross compiling tool for clang build
>>>         # apt-get install binutils-aarch64-linux-gnu
>>>         # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=dbcb124acebd8148e9e858a231f1798956dd3ca6
>>>         git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>>>         git fetch --no-tags linus master
>>>         git checkout dbcb124acebd8148e9e858a231f1798956dd3ca6
>>>         # save the config file to linux build tree
>>>         mkdir build_dir
>>>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm64 SHELL=/bin/bash
>>>
>>> If you fix the issue, kindly add following tag as appropriate
>>> Reported-by: kernel test robot <lkp@intel.com>
>>>
>>> All errors (new ones prefixed by >>, old ones prefixed by <<):
>>>
>>>>> ERROR: modpost: "gpmc_omap_get_nand_ops" [drivers/mtd/nand/raw/omap2_nand.ko] undefined!
>>
>> The issue is that CONFIG_MEMORY is not set so OMAP_GPMC driver is not built causing the above undefined symbol error.
>>
>>>
>>> Kconfig warnings: (for reference only)
>>>    WARNING: unmet direct dependencies detected for OMAP_GPMC
>>>    Depends on MEMORY && OF_ADDRESS
>>>    Selected by
>>>    - MTD_NAND_OMAP2 && MTD && MTD_RAW_NAND && (ARCH_OMAP2PLUS || ARCH_KEYSTONE || COMPILE_TEST && HAS_IOMEM && ARCH_K3
>>>
>>
>> A possible fix would be to select MEMORY along with OMAP_GPMC at the below location
>>
>> config MTD_NAND_OMAP2
>>         tristate "OMAP2, OMAP3, OMAP4 and Keystone NAND controller"
>>         depends on ARCH_OMAP2PLUS || ARCH_KEYSTONE || ARCH_K3 || COMPILE_TEST
>>         depends on HAS_IOMEM
>> 	select MEMORY
>> ^^
>>         select OMAP_GPMC if ARCH_K3 
>>         help
>>           Support for NAND flash on Texas Instruments OMAP2, OMAP3, OMAP4
>>           and Keystone platforms.
>>
>>
>> Is this OK?
> 
> Instead rather "select MEMORY if ARCH_K3"?

I think we should drop "if ARCH_K3" for both for simplicity as the driver is using gpmc_omap_get_nand_ops() from that driver.

> 
> However I had impression that selecting a user-visible options is
> discouraged, especially from within the drivers. What I would expect is
> to select it from the machine/architecture code like you did before [1]
> but was rejected by Nishanth.
> 
> https://lore.kernel.org/linux-devicetree/20211217161417.q2qwwlki7oieqzjd@headlock/

OMAP_GPMC option is not user visible. Else I would have just made MTD_NAND_OMAP2 depend on it.

> 
> In such case, your choice (with if ARCH...?) seems sensible.
> MTD_NAND_FSL_IFC already does it.
> 

cheers,
-roger