[U-Boot] [RFC PATCH 0/3] ARM: imx: mx6: Add plugin support for SPL

[Tim Harvey]

On Wed, Jan 18, 2017 at 11:01 AM, Fabio Estevam <festevam at gmail.com> wrote:
> Hi Tim,
>
> On Wed, Jan 18, 2017 at 4:49 PM, Tim Harvey <tharvey at gateworks.com> wrote:
>
>> Did you document the 'IMX6 SPL to U-Boot over serial' setup anywhere,
>> or can you talk me through what you did?
>
> It is available at doc/README.imx6 (2. Using imx_usb_loader for first
> install with SPL).

Fabio,

Thanks for pointing me in the right direction. I did manage to get
IMX6 SPL Ymodem working although I had to hack the return value of
spl_boot_device(). In my current situation with a board that has no
BOOT MODE pin strapping, and no fuses blown imx_usb_loader
spl_boot_device() returns BOOT_DEVICE_NOR which is wrong.

The SRC_SBMR register reflects the BOOT MODE pins of the chip
(strapping) but the reference manual defines SRC_GPR9 and
SRC_GPR10[28] as reserved and I don't recall the reasoning for using
these for the boot mode. Can you provide some documentation that we
can put in the code? I'm thinking there is something else missing from
this function that should be able to determine that the serial
downloader was used in my case and return BOOT_DEVICE_UART
appropriately.

Regards,

Tim