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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Wed, 13 Apr 2022 10:54:54 +0200
Message-ID: <CAK8P3a3ow9EpNAyTU9n6zC8Rmw71vJ6oaRSCHmd1qU9Z_c3RuA@mail.gmail.com>
Subject: Re: [linux-stable-rc:queue/5.4 7091/9999] drivers/staging/comedi/drivers/comedi_isadma.c:25:17:
 error: implicit declaration of function 'claim_dma_lock'
To:     kernel test robot <lkp@intel.com>
Cc:     Arnd Bergmann <arnd@arndb.de>, kbuild-all@lists.01.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Greg Ungerer <gerg@linux-m68k.org>,
        Sasha Levin <sashal@kernel.org>
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On Wed, Apr 13, 2022 at 1:07 AM kernel test robot <lkp@intel.com> wrote:
>
> Hi Arnd,
>
> FYI, the error/warning still remains.
>
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git queue/5.4
> head:   9185989d84b918f49f720061cedc29c8ed039797
> commit: 53a72858bcae7eaa7df8d167dbf60682d70f82a6 [7091/9999] m68knommu: only set CONFIG_ISA_DMA_API for ColdFire sub-arch
> config: m68k-randconfig-r011-20220412 (https://download.01.org/0day-ci/archive/20220413/202204130751.lUeRF1y2-lkp@intel.com/config)
>

I've seen a couple of reports for this now, in a few other drivers.
The intention of
my old patch was to limit the use of the set_dma_addr() etc interface
for coldfire,
because they are not implemented on the other MMU-less m68k platform
(dragonball), which caused build failures there.

However, changing the dependency to COLDFIRE means that we now build
the drivers that need this on /other/ machines that don't have the complete
API. In particular, coldfire-v4 with MMU is now able to select the COMEDI
ISA drivers that fail to build because a different part of the API
(claim_dma_lock())
is defined in asm/floppy.h on m68k instead of asm/dma.h as it is on the
other architectures.

I don't actually see any driver on coldfire using the ISA DMA API any more at
all, so I wonder if we should just drop the symbol entirely, and perhaps remove
the definitions for coldfire as well. These are the drivers I found
using the DMA
API:

$ git grep -wl set_dma_mode\\\|request_dma drivers/ sound/
drivers/ata/pata_icside.c
drivers/comedi/drivers/comedi_isadma.c
drivers/mmc/host/wbsd.c
drivers/net/appletalk/ltpc.c
drivers/net/ethernet/3com/3c515.c
drivers/net/ethernet/amd/lance.c
drivers/net/ethernet/amd/ni65.c
drivers/net/ethernet/cirrus/cs89x0.c
drivers/net/hamradio/dmascc.c
drivers/net/wan/cosa.c
drivers/net/wan/hostess_sv11.c
drivers/net/wan/sealevel.c
drivers/net/wan/z85230.c
drivers/parport/parport_pc.c
drivers/pnp/resource.c
drivers/scsi/aha1542.c
drivers/scsi/arm/cumana_2.c
drivers/scsi/arm/eesox.c
drivers/scsi/arm/powertec.c
drivers/scsi/mpt3sas/mpt3sas_base.c
drivers/scsi/mpt3sas/mpt3sas_base.h
drivers/scsi/qla1280.c
drivers/scsi/qla1280.h
drivers/scsi/qla4xxx/ql4_def.h
drivers/scsi/qla4xxx/ql4_mbx.c
drivers/scsi/qla4xxx/ql4_os.c
drivers/usb/gadget/udc/net2272.c
drivers/usb/musb/musb_cppi41.c
drivers/video/fbdev/pvr2fb.c
sound/core/isadma.c
sound/isa/es1688/es1688_lib.c
sound/isa/gus/gus_main.c
sound/soc/au1x/dma.c

Greg (Ungerer), do you see any of these that are used on Coldfire?
I can rule out most of them, but there are a few that are unclear to me.

        Arnd