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    SubjectRe: [PATCH 1/3] ata: sata_dwc_460ex: use "dmas" DT property to find dma channel
    Date
    Julian Margetson <runaway@candw.ms> writes:

    > On 12/17/2015 8:06 PM, Måns Rullgård wrote:
    >> Julian Margetson <runaway@candw.ms> writes:
    >>
    >>> On 12/17/2015 3:53 PM, Måns Rullgård wrote:
    >>>> Julian Margetson <runaway@candw.ms> writes:
    >>>>
    >>>>> On 12/17/2015 2:51 PM, Måns Rullgård wrote:
    >>>>>> Julian Margetson <runaway@candw.ms> writes:
    >>>>>>
    >>>>>>> On 12/17/2015 1:59 PM, Måns Rullgård wrote:
    >>>>>>>> Julian Margetson <runaway@candw.ms> writes:
    >>>>>>>>
    >>>>>>>>> I have been running my machine mostly configured for pciex1 thus with
    >>>>>>>>> the sata_dwc disabled.
    >>>>>>>>> The changes to sata_dwc-460ex do cause an oops.
    >>>>>>>>> I will try to give more detailed info over this weekend .
    >>>>>>>> The driver as is upstream would do that since it unconditionally
    >>>>>>>> dereferences a null pointer in the probe function. My patch fixes that
    >>>>>>>> as a side-effect.
    >>>>>>>>
    >>>>>>> patching file drivers/ata/Kconfig
    >>>>>>>
    >>>>>>> Hunk #1 FAILED at 296.
    >>>>>> [...]
    >>>>>>
    >>>>>>> root@julian-VirtualBox:/usr/src/linux-3.18.25#
    >>>>>> The patch is against 4.4-rc5.
    >>>>>>
    >>>>> CC drivers/ata/sata_dwc_460ex.o
    >>>>>
    >>>>> drivers/ata/sata_dwc_460ex.c:198:15: error: variable ‘sata_dwc_dma_dws’ has initializer but incomplete type
    >>>>>
    >>>>> static struct dw_dma_slave sata_dwc_dma_dws = {
    >>>>> ^
    >>>> It builds, albeit with an unrelated warning, using the attached config.
    >>>> Maybe there's a missing config dependency somewhere.
    >>>>
    >>> I am attempting to cross compile under Ubuntu 14.04 X86 in Virtualbox
    >>> with your .config.
    >>> 4.4.0-rc5 builds ok with no patches applied .
    >>> Once your patch is applied it fails to build .
    >>>
    >>> CC drivers/ata/sata_dwc_460ex.o
    >>> drivers/ata/sata_dwc_460ex.c:198:15: error: variable ‘sata_dwc_dma_dws’ has initializer but incomplete type
    >>> static struct dw_dma_slave sata_dwc_dma_dws = {
    >>> ^
    >> Bizarre. This is what it looks like here:
    >>
    >> mru@unicorn:/tmp/linux-sata$ git status
    >> On branch sata-dwc
    >> nothing to commit, working directory clean
    >> mru@unicorn:/tmp/linux-sata$ git describe
    >> v4.4-rc5
    >> mru@unicorn:/tmp/linux-sata$ sha1sum /tmp/0001-ata-sata_dwc_460ex-use-dmas-DT-property-to-find-dma-.patch
    >> e300971aa483390f82de2e9120dc16e460e74feb /tmp/0001-ata-sata_dwc_460ex-use-dmas-DT-property-to-find-dma-.patch
    >> mru@unicorn:/tmp/linux-sata$ git am /tmp/0001-ata-sata_dwc_460ex-use-dmas-DT-property-to-find-dma-.patch
    >> Applying: ata: sata_dwc_460ex: use "dmas" DT property to find dma channel
    >> mru@unicorn:/tmp/linux-sata$ sha1sum .config
    >> 4e7615b8d2fa9a1c4b4ae9ffc363aefcaf3789ca .config
    >> mru@unicorn:/tmp/linux-sata$ make ARCH=powerpc CROSS_COMPILE=powerpc64-none-linux-gnu- oldconfig
    >> HOSTCC scripts/basic/fixdep
    >> HOSTCC scripts/kconfig/conf.o
    >> SHIPPED scripts/kconfig/zconf.tab.c
    >> SHIPPED scripts/kconfig/zconf.lex.c
    >> SHIPPED scripts/kconfig/zconf.hash.c
    >> HOSTCC scripts/kconfig/zconf.tab.o
    >> HOSTLD scripts/kconfig/conf
    >> scripts/kconfig/conf --oldconfig Kconfig
    >> #
    >> # configuration written to .config
    >> #
    >> mru@unicorn:/tmp/linux-sata$ make ARCH=powerpc CROSS_COMPILE=powerpc64-none-linux-gnu- drivers/ata/sata_dwc_460ex.o
    >> scripts/kconfig/conf --silentoldconfig Kconfig

    [...]

    >> CC drivers/ata/sata_dwc_460ex.o
    >> drivers/ata/sata_dwc_460ex.c: In function 'dma_dwc_xfer_setup':
    >> drivers/ata/sata_dwc_460ex.c:383:20: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
    >> dma_addr_t addr = (dma_addr_t)&hsdev->sata_dwc_regs->dmadr;
    >> ^
    >> mru@unicorn:/tmp/linux-sata$
    >>
    >> Patch file and .config attached.
    >>
    >> Looking into that warning, I doubt it works as is, but that's not caused
    >> by my patch. I can try to come up with a fix, but again, I can't test it.
    >>
    > I am using
    >
    > make ARCH=powerpc CROSS_COMPILE=powerpc-linux-gnu-

    Shouldn't matter since the compiler flags include -m32, and I only had a
    powerpc64 toolchain built. Anyhow, I built a 32-bit toolchain and it
    still builds.

    Just to make sure you applied the patch correctly:

    mru@unicorn:/tmp/linux-sata$ sha1sum drivers/ata/sata_dwc_460ex.c
    c8a7927840aade75ac62b04a2c9acc8335a34d6f drivers/ata/sata_dwc_460ex.c

    Digging deeper into that warning, it is clearly a bug which has always
    been there. The reason it ever worked appears to be that the 460EX has
    a dedicated DMA unit hard-wired to the SATA controller ignoring that
    address. The situation is similar on my hardware.

    --
    Måns Rullgård


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