[U-Boot] problem to boot i.MX28 custom platform

Fabio Estevam
2013-02-28T14:39:36Z

Hi Hector,

Hector Palacios wrote:

> Apparently the problem was due to my platform suffering a hardware
> specific VDDD brownout during the initialization.
>
> Just in case it helps anybody, the reason why I was not able to see
> anything on the DUART port during SPL initialization, despite having
> enabled CONFIG_SPL_SERIAL_SUPPORT and having serial_puts() on the SPL
> code, was that my platform uses alternate pins for the DUART than the
> default used by the BOOT ROM and the EVK, so apart from configuring the
> correct IOMUX, I needed to unconfigure the pins used by BOOT ROM for the
> DUART (on board/<vendor>/iomux.c):
>
> @@ -33,8 +33,12 @@
>
> const iomux_cfg_t iomux_setup[] = {
> /* DUART */
> - MX28_PAD_PWM0__DUART_RX,
> - MX28_PAD_PWM1__DUART_TX,
> + /* 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,
>
> /* MMC0 */
> MX28_PAD_SSP0_DATA0__SSP0_D0 | MUX_CONFIG_SSP0,
> @@ -159,9 +163,6 @@ const iomux_cfg_t iomux_setup[] = {
> MX28_PAD_SSP2_MISO__SSP2_D0 | MUX_CONFIG_SSP2,
> MX28_PAD_SSP2_SS0__SSP2_D3 |
> (MXS_PAD_3V3 | MXS_PAD_8MA | MXS_PAD_PULLUP),
> - /* I2C */
> - MX28_PAD_I2C0_SCL__I2C0_SCL,
> - MX28_PAD_I2C0_SDA__I2C0_SDA,
> };
>
> #define HW_DRAM_CTL29 (0x74 >> 2)

Thanks for sharing your solution. It seems that the other mx28 boards we currently have all use
MX28_PAD_PWM0__DUART_RX / MX28_PAD_PWM1__DUART_TX for DUART and then we never faced this issue.

It would be great if you can submit a patch for adding support to your board in U-boot.

Regards,

Fabio Estevam