[PATCH 0/5 RFC] mmc: sdhci-iproc: add bcm2835 support

Eric Anholt eric at anholt.net
Thu Jan 28 14:19:56 PST 2016


Stefan Wahren <stefan.wahren at i2se.com> writes:

>> Eric Anholt <eric at anholt.net> hat am 19. Januar 2016 um 22:00 geschrieben:
>>
>>
>> Stefan Wahren <stefan.wahren at i2se.com> writes:
>>
>> > This patch series based on the suggestion of Scott Branden to implement
>> > bcm2835 support into sdhci-iproc [1].
>> >
>> > These changes provide the following advantages:
>> > * no need to maintain a separate driver for bcm2835
>> > * improve support and test coverage of bcm2835 mmc support
>> > * get the rid of SDHCI_CAPABILITIES hack in bcm2835_sdhci_readl
>> > * increase write performance by avoiding delays in write ops
>> >
>> > Patch 1 and 2 adopt two sdhci-bcm2835 fixes to sdhci-iproc. The third patch
>> > tries to specify as much quirks as possible in the bcm283x.dtsi as possible.
>> > Patch 4 and 5 are the actually changes for bcm2835 support.
>> >
>> > These series has been tested on Raspberry Pi B with dd (direct I/O):
>> >
>> > sdhci-bcm2835
>> >
>> > 378 kB/s WRITE
>> > 10,6 MB/s READ
>> >
>> > sdhci-iproc (after applying patch series)
>> >
>> > 881 kB/s WRITE
>> > 10,8 MB/s READ
>>
>> I started a while ago at looking at merging the sdhost driver (for the
>> other controller on these boards that you can use instead), since
>> apparently the hardware's a better choice to use. This looks like a
>> really nice simplification for us for the Arasan mode, though. Would
>> you also want to delete the old 2835 driver after this series?
>
> Yes, that would be a necessary step. I don't know when it's the right time.
>
> What is the usual procedure for such a necessary driver?

If the kernel still supports the hardware, just in a different source
file, I don't see any problem with removing it immediately.
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