AM5716: AM5716 board does not boot when UART2 is selected as Console.

Hi Mahesh,

Is the behavior same on AM571x-IDK i.e the TI board?

- Keerthy

Hi Keerthy,

Thanks for your quick response.

Yes. I can conform that behavior is same on AM571x-IDK(TMDXIDK5718) for above mentioned both options.

For above mentioned use case and problem:

(1) AM571x-idk board does not boot at all.

(2) On AM571x-idk board, I can see only Boot messages on UART3 console. I do not have access of uart2 on am571x-idk, so can not see linux log messages. But after 1 minute i can access board by connecting my PC to eth0 on putty. I am able to access the board and it is working.

Regards,

Mahesh

Mahesh,

One thing in the description is a bit confusing: 

"I tried following thing to check wether UART2 is working as a console for LINUX.

chosen {
stdout-path = &uart3;
};

&uart3 {
status = "okay";
interrupts-extended = <&crossbar_mpu GIC_SPI 69 IRQ_TYPE_LEVEL_HIGH
&dra7_pmx_core 0x248>;
};"

The above is for UART3 right?

What were the changes you did specific to UART2?

- Keerthy

Hi Keerthy,

For UART2 following chages has been done.

I have made changes in /TI_SDK_AM57XX/board-support/u-boot-2019.01+gitAUTOINC+a141f7abfd-ga141f7abfd/arch/arm/dts/am57xx-idk-common.dtsi

chosen {
stdout-path = &uart2;
};

&uart2 {
status = "okay";
interrupts-extended = <&crossbar_mpu GIC_SPI 68 IRQ_TYPE_LEVEL_HIGH
&dra7_pmx_core 0x3F0>;

}

With this i have compiled u-boot and generated MLO and u-boot.img is placed in boot partition of SD card.

PROBLEM: board does not boot at all. please help me what i am missing here in boot for making UART2 as console

Regards,

Mahesh

Mahesh,

The above change you have done is on u-boot dts. Can you share the kernel dts
changes that you did get linux prints on uart2?

UART2 is working in Linux on your custom board as well right?

- Keerthy

Hi Mahesh,

Could you try the below diff in u-boot:

diff --git a/board/ti/am57xx/mux_data.h b/board/ti/am57xx/mux_data.h
index 8a216a7855..8bb98d1bfd 100644
--- a/board/ti/am57xx/mux_data.h
+++ b/board/ti/am57xx/mux_data.h
@@ -1185,8 +1185,11 @@ const struct pad_conf_entry core_padconf_array_vout_am571x_idk[] = {
 
        {MCASP5_ACLKX, (M12 | PIN_INPUT | MANUAL_MODE)},        /* mcasp5_aclkx.pr2_pru1_gpi1 */
        {MCASP5_FSX, (M12 | PIN_INPUT | MANUAL_MODE)},  /* mcasp5_fsx.pr2_pru1_gpi2 */
-       {UART2_RXD, (M0 | PIN_INPUT)},  /* uart2_rxd.uart2_rxd */
-       {UART2_TXD, (M0 | PIN_OUTPUT)}, /* uart2_txd.uart2_txd */
+       {UART2_RXD, (M4 | PIN_INPUT)},  /* uart2_rxd.uart2_rxd */
+       {UART2_TXD, (M0 | PIN_OUTPUT)}, /* uart2_txd.uart2_txd */
+       {UART2_CTSN, (M0 | PIN_INPUT)}, /* uart2_ctsn.uart2_ctsn */
+       {UART2_RTSN, (M0 | PIN_OUTPUT)},        /* uart2_rtsn.uart2_rtsn */
+
        {VIN2A_D5, (M13 | PIN_OUTPUT_PULLDOWN | MANUAL_MODE)},  /* vin2a_d5.pr1_pru1_gpo2 */

Regards,
Keerthy

Hi Keerthy,

Thanks to address the issue. Issue is resolved but want to understand.

Uart2 pins are already there in my mux_data.h. That is why UART2 is working Linux console messages as well as linux application.

+       {UART2_RXD, (M4 | PIN_INPUT)},  /* uart2_rxd.uart2_rxd */
+       {UART2_TXD, (M0 | PIN_OUTPUT)}, /* uart2_txd.uart2_txd */

I had configured UART2_CTSN(D27), and UART2_RTSN(C28) as a uart3.

Now Uart3 is configured on AB3 and AA4.     UART2_CTSN(D27) and UART2_RTSN(C28) are unused now.

With this UART2 is working for boot and linux messages.

I have two question:

(1) why UART2_CTSN(D27), and UART2_RTSN(C28) as a uart3 creating problem with UART2 functionality?

(2) 

&uart2 {
status = "okay";
interrupts-extended = <&crossbar_mpu GIC_SPI 68 IRQ_TYPE_LEVEL_HIGH
&dra7_pmx_core 0x3F0>;

}

 Is this correct: &dra7_pmx_core 0x3F0 ? What is meaning of 0x3F0?

Regards,

Mahesh