[U-Boot] ls1021atwr reset issue (was [ANN] U-Boot v2015.10-rc4 released)

[Otavio Salvador]

On Thu, Oct 1, 2015 at 4:14 PM, Tom Rini <trini at konsulko.com> wrote:
> On Thu, Oct 01, 2015 at 04:09:46PM -0300, Fabio Estevam wrote:
>> On Thu, Oct 1, 2015 at 12:19 PM, Sinan Akman <sinan at writeme.com> wrote:
>> >   I took a further look at this. I believe this won't work as readw
>> > will now return the data in the wrong endianness. I think Wolfgang
>> > also already pointed out at this. We would need to use the macro with
>> > correct endianness for different platforms (ls1021atwr would need
>> > big endian) and control this based on the watchdog endian setting in dts.
>>
>> The imx platforms do not use dts in U-boot yet.
>>
>> >
>> >   However, there seems to be other problems here. The original
>> > fix was intending to preserve the current set bits in wcr and
>> > enable DTE. But in the case of ls1021atwr, the watcdog is not
>> > initialized and out of reset we have SRS bit is set. This would
>> > disable wdog_rst and prevent reset from working. Before the
>> > fix it was actually the accidental setting of SRS to zero made
>> > the reset working because a writew(WCR_WDE, &wdog->wcr)
>> > would clear that bit, setting WDE alone would not generate wdog_rst.
>> >
>> >   So I believe a proper fix would have the following steps :
>> >   - move watchdog driver to DM so that we can make use of endian type
>> >   - use macros with the endian type for accessing the registers
>> >   - enable hw_watchdog for the board so that it gets initialized to
>> > a known value
>> >   - reset SRS to enable generation of wdog_rst, this will reset immediately
>> > with 0x00 default WT value.
>> >   - or program the timeout and enable WDE so the board
>> > resets after a longer timeout value if desired
>> >
>> >   Does this make sense to everyone ?
>>
>> Looks good. 2015.10 release is only a few days away: do you think you
>> could implement your proposal for the upcoming release?
>
> That seems rather large.  Is there something we can revert today so
> that:
> a) All boards in v2015.07 continue to work in v2015.10 as well as before
> b) Any new boards are not introduced in a totally broken state?

Agreed; I prefer to revert the watchdog changes and break ls102x than
introduce such big change.

-- 
Otavio Salvador                             O.S. Systems
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