[U-Boot] Are non-default configurations expected to work? Re: usb: dwc2: does not compile in 2016-rc3 when updating from -rc1.

[Marek Vasut <marex@denx.de>]

On Sunday, January 10, 2016 at 08:28:24 PM, Tom Rini wrote:
> On Sun, Jan 10, 2016 at 08:18:39PM +0100, Marek Vasut wrote:
> > On Sunday, January 10, 2016 at 08:16:55 PM, Tom Rini wrote:
> > > On Sun, Jan 10, 2016 at 08:06:59PM +0100, Marek Vasut wrote:
> > > > On Sunday, January 10, 2016 at 08:04:06 PM, Tom Rini wrote:
> > > > > On Sun, Jan 10, 2016 at 07:39:29PM +0100, Pavel Machek wrote:
> > > > > > > > > Pristine u-boot 2016.01-rc4 compiles fine for CV SoCDK. Can
> > > > > > > > > you please test mainline _before_ reporting issues ?
> > > > > > > > 
> > > > > > > > Can you please test mainline before complaining?
> > > > > > > 
> > > > > > > Yes I _did_ test mainline AND booted it on the actual board.
> > > > > > > The USB does work (if you disable dcache, which is unrelated
> > > > > > > bug). It would be very nice if you did the same thing before
> > > > > > > you start yelling on the list that there is a bug.
> > > > > > > 
> > > > > > > The config you use and the one produced by make
> > > > > > > socfpga_cyclone5_defconfig differ. Use the mainline one,
> > > > > > > otherwise you will observe possible problems.
> > > > > > 
> > > > > > Of course they differ. That's why they are called configuration
> > > > > > _options_.
> > > > > 
> > > > > True.
> > > > > 
> > > > > > > > With d77a092dd3619ca747fb8290ae8f255e9799aaa6 and attached
> > > > > > > > .config, I get the failure. No, CONFIG_DM_USB is not set in
> > > > > > > > the config, which is probably the problem.
> > > > > > > 
> > > > > > > Again, the problem does not happen if you use mainline config.
> > > > > > > If you enable random options, you might run into random
> > > > > > > problems.
> > > > > > > 
> > > > > > > > Maybe socfpga should select DM_USB or depend on it?
> > > > > > > 
> > > > > > > u-boot$ git grep DM_USB configs/socfpga_*
> > > > > > > configs/socfpga_arria5_defconfig:CONFIG_DM_USB=y
> > > > > > > configs/socfpga_cyclone5_defconfig:CONFIG_DM_USB=y
> > > > > > > configs/socfpga_de0_nano_soc_defconfig:CONFIG_DM_USB=y
> > > > > > > configs/socfpga_mcvevk_defconfig:CONFIG_DM_USB=y
> > > > > > > configs/socfpga_sockit_defconfig:CONFIG_DM_USB=y
> > > > > > > configs/socfpga_socrates_defconfig:CONFIG_DM_USB=y
> > > > > > > 
> > > > > > > So your config is broken or outdated, please update your
> > > > > > > config.
> > > > > > 
> > > > > > No. Mainline is broken. Yes, it happens to work with defconfig.
> > > > > > But it should work with any configuration user can select.
> > > > > 
> > > > > So, here's the problem.  Disabling CONFIG_DM_USB is not a long term
> > > > > solution.
> > > > 
> > > > CONFIG_DM_USB is enabled though.
> > > > 
> > > > > If there's a problem when CONFIG_DM_USB is not set, it should
> > > > > be diagnosed and fixed, especially since we might have a mirror of
> > > > > the issue inside the DM code, or it might be a more core problem
> > > > > and we simply luck out in the DM case.
> > > > 
> > > > The problem is if you have CONFIG_USB enabled, but _without_
> > > > CONFIG_DM_USB. In that case, the DWC2 driver expects you to define a
> > > > macro which specifies the base address of the USB controller.
> > > > Otherwise the driver picks this info from the OF.
> > > > 
> > > > I believe there is no problem with this, the driver covers both DM
> > > > and non-DM operation this way.
> > > 
> > > That's it?  Yes, we should have the missing define added and a lack of
> > > it is a bug we should fix.
> > 
> > Wrong, the macro was intently removed from all the socfpga config files
> > because: a) do not want to hardcode any addresses on socfpga, they
> > should come from DT b) we do want to support multiple controllers and
> > that is not possible without
> > 
> >    CONFIG_DM_USB
> > 
> > CONFIG_DM_USB is a hard requirement on SoCFPGA.
> 
> Then with your SoCFPGA hat on, you need to fix the Kconfig so invalid
> combinations can't happen.

Invalid configurations do not happen in mainline, everything is compile tested.
In case someone wants to bulletproof the config, patches are welcome. I am not
certain what should select CONFIG_DM_USB, Simon might help here.