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