[U-Boot] [PATCH] sunxi: Fix wrong serial console setup in Forfun Q88DB tablet

[Hans de Goede]

Hi,

On 08-09-15 16:49, Siarhei Siamashka wrote:
> The Forfun Q88DB tablet was unbootable since commit
> b6006baf9c2553543e3384983d23d95efbf24fa6 ("sunxi: Move all
> boards to the driver-model"). Appears that this is caused
> by the wrong serial console setup in the SPL. The serial
> console should use PG3/PG4 pins according to the FEX file.
>
> Signed-off-by: Siarhei Siamashka <siarhei.siamashka at gmail.com>

Thanks I've queued this up in my tree and it will be part
of my next pull-req.

> ---
>   configs/forfun_q88db_defconfig | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> While this should be a correct fix, the reason why the tablet failed
> to boot is a bit unclear. Without the correct CONS_INDEX setup, we
> should just get the serial console routed to the nonexisting pins
> B19/B20, and this is expected to be harmless. Maybe the DM code
> in the main U-Boot binary can't initialize serial console properly
> if we have a mismatch between the settings in the dts file and the
> CONS_INDEX settings in the SPL?

Yes this is a problem with the dm code vs the dts.  I hit the same
problem when creating a generic q8_a13_tablet_defconfig.

Talking about the generic q8_a13_tablet_defconfig (currently in my
sunxi-wip, soon upstream). This one should work fine for the
forfun_q88db too. The idea is to have a single config which works
on all q8 a13 tablets as it is impossible for users to figure
out which variant they exactly have.

We are still figuring out what to do wrt different touchscreen
controllers / accelerometers, but we can likely come up with some
autodetection for that (either in u-boot or in the kernel).

Since currently we do not support any touchscreen controllers /
accelerometers in such tablets in the mainline kernel this is a non
issue for now.

Can you try this new defconfig on your forfun_q88db? An added advantage
is that it comes with a kernel dts too, which the forfun seems to be
missing (currently only available in my sunxi-wip kernel branch).

If the q8_a13_tablet_defconfig works well for the forfun_q88db I would
like to drop that as a target from u-boot, is that ok with you ?

Regards,

Hans

>
> diff --git a/configs/forfun_q88db_defconfig b/configs/forfun_q88db_defconfig
> index 30cead7..30e0937 100644
> --- a/configs/forfun_q88db_defconfig
> +++ b/configs/forfun_q88db_defconfig
> @@ -13,7 +13,7 @@ CONFIG_VIDEO_LCD_BL_PWM="PB2"
>   CONFIG_DEFAULT_DEVICE_TREE="sun5i-a13-forfun-q88db"
>   # CONFIG_SYS_MALLOC_CLEAR_ON_INIT is not set
>   CONFIG_SPL=y
> -CONFIG_SYS_EXTRA_OPTIONS="AXP209_POWER"
> +CONFIG_SYS_EXTRA_OPTIONS="CONS_INDEX=2,AXP209_POWER"
>   # CONFIG_CMD_IMLS is not set
>   # CONFIG_CMD_FLASH is not set
>   # CONFIG_CMD_FPGA is not set
>