[U-Boot] i.MX28 u-boot SPL fail

[Marco Cavallini]

2015-02-12 16:57 GMT+01:00 Marco
> Hi,
> On a custom i.MX28 board I am using u-boot-2015.01.
> The debug port DUART is not the same as i.MX28, so I changed these
> settings in iomux.c:
>
> const iomux_cfg_t iomux_setup[] = {
>   /* DUART */
> // MX28_PAD_PWM0__DUART_RX,
> // MX28_PAD_PWM1__DUART_TX,
>
>   /* DUART */
>   /* Unconfigure BOOT ROM default DUART */
>   MX28_PAD_PWM0__GPIO_3_16,
>   MX28_PAD_PWM1__GPIO_3_17,
>   /* Configure DUART on alternate pins */
>   MX28_PAD_I2C0_SCL__DUART_RX,
>   MX28_PAD_I2C0_SDA__DUART_TX,
>
> I enabled #define CONFIG_SPL_SERIAL_SUPPORT and built uboot with :
> make u-boot.sb
> At last I can program the board only using MfgTools or 'mxsldr', or it
> seems working.
> The problem is that I get no messages on output debug port or some
> random chars every 5, 10 boots
>
> At this point I have some doubts and questions:
> - is the u-boot.sb suitable to be run from MfgTools?
> - should I expect any char on the serial debug port?
> - do I have to use the 'elftosb' tool to convert my binary? (README says not)



I have already studied this useful document
http://www.denx.de/wiki/pub/U-Boot/MiniSummitELCE2013/2013-u-boot-mxs-without-fsl-tools.pdf

I do not need any encryption.
I did exactly the same as explained here
http://www.denx-cs.de/doku/?q=m28evkrunuboot

 make u-boot.sb

Then I do not have SD nor other storage so I mus use USB firmware upload
http://www.denx-cs.de/doku/?q=m28evkusbdownloader

Load u-boot.sb onto the device:
 sudo ./mxsldr <path to u-boot.sb>

This procedure works perfectly on the i.MX28evk, but doesn't on my
custom board so I supposed that u-boot-2015.01 STL works perfecly on
i.MX28 and MfgTools upload.

Differences are:
- DUART on alternate pins
- DDR different
- eMMC instead of NAND

I don't know how i.MX28 ROM boot works so my question are:
- should I see something on the serial port BEFORE the DDR settings are done?
- if I put some code in mxs_common_spl_init() is this executed
immediately  BEFORE the DDR (and power) settings are done?

Thank you
--
Marco