[U-Boot] [PATCH v2 0/6] Add support for MIPS Creator CI20

[Daniel Schwierzeck]

Hi Ezequiel,

Am 12.12.18 um 14:58 schrieb Ezequiel Garcia:
> A new round.
> 
> For this new round:
> 
>  * Replaced infinite while loop with wait_for_bit.
>  * Added a MAINTAINERS file. If anyone wants to co-maintain this,
>    please let me know.
> 
> This is based on top of yesterday's master (ee168783ae8) and has
> been tested by SD-card booting both U-Boot and Linux. Booting
> Linux via TFTP was also tested.
> 
> Toolchain used to test:
> 
> $ mips-linux-gcc -v
> Using built-in specs.
> COLLECT_GCC=mips-linux-gcc
> COLLECT_LTO_WRAPPER=/home/zeta/.buildman-toolchains/gcc-7.3.0-nolibc/mips-linux/bin/../libexec/gcc/mips-linux/7.3.0/lto-wrapper
> Target: mips-linux
> Configured with: /home/arnd/git/gcc/configure --target=mips-linux --enable-targets=all --prefix=/opt/crosstool/gcc-7.3.0-nolibc/mips-linux --enable-languages=c --without-headers --disable-bootstrap --disable-nls --disable-threads --disable-shared --disable-libmudflap --disable-libssp --disable-libgomp --disable-decimal-float --disable-libquadmath --disable-libatomic --disable-libcc1 --disable-libmpx --enable-checking=release
> Thread model: single
> gcc version 7.3.0 (GCC) 
> 
> SPL size:
> 
> $ size spl/u-boot-spl
>    text	   data	    bss	    dec	    hex	filename
>    9252	    752	    736	  10740	   29f4	spl/u-boot-spl
> 
> I've pushed a branch to https://github.com/ezequielgarcia/u-boot/tree/ci20-v2
> and made sure travis passed.
> 

Thanks for working on this but the problem with the original patch
series was that it was not fully driver model compatible and that stuff
like watchdog, reset and pin-muxing was open-coded instead of using the
proper frameworks. As the ship is sailing towards having only driver
model and device tree in U-Boot proper, it doesn't make sense to accept
new SoC/boards with legacy code especially if there is no active
maintainer who would do the conversion work. And with the upcoming dead
lines for DM conversions, boards with legacy code will be removed when
not converted. This is also one of the reasons why the Ingenic SoC
support we already had in mainline was removed. And readding parts of
the removed code doesn't make sense either because the patch series is
based on that old Ingenic SoC code.

I wanted to work on Marek's patch series to fix those issues because
it's quite some work which I couldn't expect from Marek ;)
But I got stuck with EJTAG because halting the CPU didn't work. Then I
hadn't time anymore.

I'm little busy right now so I can't do a detailed review. But the
issues which should be addressed at first are:

- fix all SPDX license identifiers
- convert GPIO driver to DM
- add a DM watchdog driver
- implement machine reset with the generic watchdog reset (see BMIPS for
an example)
- don't use SoC specific start.S and u-boot-spl.lds, the generic code is
now configurable enough and non-generic things could be done in a
lowlevel_init.S
- reduce the hundreds of definitions of register addresses to the ones
really needed in assembly or SPL. This stuff should come from device tree
- define the remaining register base addresses as physical addresses and
establish a mapping with ioremap_nocache()


-- 
- Daniel