AM572x IDK changing debug console in Linux

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HI,

UART 1 settings in u-boot:


--- a/board/ti/am57xx/mux_data.h
+++ b/board/ti/am57xx/mux_data.h
@@ -481,8 +481,8 @@ const struct pad_conf_entry core_padconf_array_essential_am572x_idk[] = {
};

const struct pad_conf_entry early_padconf[] = {
- {UART2_CTSN, (M2 | PIN_INPUT_SLEW)}, /* uart2_ctsn.uart3_rxd */
- {UART2_RTSN, (M1 | PIN_INPUT_SLEW)}, /* uart2_rtsn.uart3_txd */
+ {UART1_RXD, (M0 | PIN_INPUT_SLEW)}, /* */
+ {UART1_TXD, (M0 | PIN_INPUT_SLEW)}, /* */

diff --git a/arch/arm/cpu/armv7/omap5/hw_data.c b/arch/arm/cpu/armv7/omap5/hw_data.c
index fc99135..47ad9c3 100644
--- a/arch/arm/cpu/armv7/omap5/hw_data.c
+++ b/arch/arm/cpu/armv7/omap5/hw_data.c
@@ -405,7 +405,7 @@ void enable_basic_clocks(void)
(*prcm)->cm_l3init_hsmmc2_clkctrl,
(*prcm)->cm_l4per_gptimer2_clkctrl,
(*prcm)->cm_wkup_wdtimer2_clkctrl,
- (*prcm)->cm_l4per_uart3_clkctrl,
+ (*prcm)->cm_l4per_uart1_clkctrl,
(*prcm)->cm_l4per_i2c1_clkctrl,
#ifdef CONFIG_DRIVER_TI_CPSW
(*prcm)->cm_gmac_gmac_clkctrl,
diff --git a/arch/arm/dts/am572x-idk.dts b/arch/arm/dts/am572x-idk.dts
index b340551..3054f52 100644
--- a/arch/arm/dts/am572x-idk.dts
+++ b/arch/arm/dts/am572x-idk.dts
@@ -19,7 +19,7 @@
"ti,dra7";

chosen {
- stdout-path = &uart3;
+ stdout-path = &uart1;
};

And in U-Boot I do use UART1 now - there is no issue with it.

The problem is with Linux kernel (its configuration). I've pasted my changes to Kernel DTS (in the previous message), but apparently it is not enough.

BR,
Łukasz

Hi Łukasz

Sorry, I've missed one more modification needed:
#define CONSOLEDEV "ttyO2" ==> modify to match uart1

in u-boot/include/configs/am57xx_evm.h

Kernel should take the already configured uart as a debug console.

Best Regards,
Yordan

Hi,

No, this is also setup manually with

setenv console "ttyO0,115200n8"

U-boot works with UART1.

There is problem with linux.
CONFIG_DEBUG_LL has early printk option for 8250_omap.c driver, but I don't know how to adjust it.

Hi,

One more idea - I do have access to UART3 and UART1.

Is there a way to adjust CONFIG_DEBUG_LL to have UART3 as a debug one?

BR,
Łukasz

Hi
Is your problem solved?

Is console working in Linux?

Thanks

Hi,

Yes, it all works now.

BR,
Łukasz

Can you please let me know what was the change for enabling the console in kernel?

thanks for reporting that the problem was solved. we really appreciate this input.

Hi Rogerio,

Problem is not solved completely yet. We are able to boot u-boot at uart3 but kernel is not booting at uart3(kernel is booting uart0). Could you please provide the changes required at kernel to make it work at uart3.

Thanks and Regards
Deshvir Malik

Dear All,

I don't remember exactly what was the reason (last reply to the post is from Dec 9, 2016).

One should pay attention to:

- Early u-boot (spl) pin assignment (UART3)
- Enabled clocks
- Change CONSOLEDEV in u-boot and pass proper console= env variable to Linux

In Linux:
- Modify stdout-path

And DEBUG_LL was not working when I checked last time (now I do not it).

Best regards,
Łukasz

Hi All,

Thanks for your inputs. We have modified the below code in bootloader at /include/configs/am335x_evm.h
"init_console=" \
"if test $board_name = A335_ICE; then "\
"setenv console ttyO3,115200n8;" \
"else " \
"setenv console ttyO3,115200n8;" \
"fi;\0" \

After doing this modification, kernel logs are coming at uart3.
Previously, we only setting console parameter, but above step is mandatory to make the kernel work at uart3.


Thanks and Regards
Deshvir Malik