Linux/AM3351: Changing debug UART

khageswararao bongu

Expert 1380 points

Part Number: AM3351

Tool/software: Linux

Hi, i am using Processor SDK 3.00.00.04.

i am trying to change debug port to UART 5 in u-boot. i modified below changes but still i am not getting debug logs.

------>.config

CONFIG_CONS_INDEX=5

------>board/ti/am335x/mux.c

static struct module_pin_mux uart4_pin_mux[] = {
    {OFFSET(gmii1_txd3), (MODE(3) | PULLUP_EN | RXACTIVE)},   /* UART4_RXD */
   {OFFSET(gmii1_txd2), (MODE(3) | PULLUDEN)},       /* UART4_TXD */
    {-1},

};

over 7 years ago

0 Kemal R. Shakir over 7 years ago

TI__Guru 55345 points

Hello khageswararao,

To change the debug console you just need to change two things: UART console in menuconfig and stdout-path in U-Boot device tree.

$ cd <Processor SDK>/
$ make u-boot_clean && make u-boot
$ cd board-support/u-boot-<version>/
$ ARCH=arm make menuconfig

ARM architecture ---> (5) UART used for console
Exit
Exit
Do you wish to save your new configuration?
< Yes >
$ cp .config configs/am335x_evm_defconfig
$ cd ../../

Change the stdout-path = &uart0; to stdout-path = &uart5; in your U-Boot's device tree in <Processor SDK>/board-support/u-boot-<version>/arch/arm/dts/am335x-evm.dts

$ make u-boot_clean && make u-boot

And boot your board with the new MLO and u-boot.img

Best regards,
Kemal

0 khageswararao bongu over 7 years ago in reply to Kemal R. Shakir

Expert 1380 points

i reverted all my previous changes.
after modifying in menu config, i got CONFIG_CONS_INDEX=5 in am335x_evm_defconfig file.

in arch/arm/dts/am335x-evm.dts i did below changes.

1. stdout-path = &uart4;
2. uart4_pins: pinmux_uart4_pins {
pinctrl-single,pins = <
0x11C (PIN_INPUT_PULLUP | MUX_MODE3) /* uart4rxd.uart0_rxd */
0x120 (PIN_OUTPUT_PULLDOWN | MUX_MODE3) /* uart4txd.uart0_txd */
>;
};
3.&uart4 {
pinctrl-names = "default";
pinctrl-0 = <&uart4_pins>;

status = "okay";
};

in board/ti/am335x/mux.c
static struct module_pin_mux uart4_pin_mux[] = {
//{OFFSET(gpmc_wait0), (MODE(6) | PULLUP_EN | RXACTIVE)}, /* UART4_RXD */
//{OFFSET(gpmc_wpn), (MODE(6) | PULLUDEN)}, /* UART4_TXD */
//{-1},
{PIN_GMII1_TXD3, (MODE(3) | PULLUP_EN | RXACTIVE)}, /* UART4_RXD */
{PIN_GMII1_TXD2, (MODE(3) | PULLUDEN)}, /* UART4_TXD */
{-1},
};

after booted with the new MLO and u-boot.img

Still i am not getting logs on uart4.
Please

0 Kemal R. Shakir over 7 years ago in reply to khageswararao bongu

TI__Guru 55345 points

You are telling me that you can compile U-Boot with this pinmuxing? Why aren't you following existing pinmuxing style?
Use this instead, and also comment out these pins from rgmii1_pin_mux and mii1_pin_mux to make sure that they will not get overwritten later.
{OFFSET(mii1_txd3), (MODE(3) | PULLUP_EN | RXACTIVE)}, /* UART4_RXD */
{OFFSET(mii1_txd2), (MODE(3) | PULLUDEN)}, /* UART4_TXD */
On which reference design your board is based on? Are you sure that the <Processor SDK>/board-support/u-boot-<version>/arch/arm/dts/am335x-evm.dts is its device tree?

0 khageswararao bongu over 7 years ago in reply to Kemal R. Shakir

Expert 1380 points

we are using evm_sk for reference design.
in .config
CONFIG_SYS_CONFIG_NAME="am335x_evm"

in mux.c
static struct module_pin_mux uart4_pin_mux[] = {
//{OFFSET(gpmc_wait0), (MODE(6) | PULLUP_EN | RXACTIVE)}, /* UART4_RXD */
//{OFFSET(gpmc_wpn), (MODE(6) | PULLUDEN)}, /* UART4_TXD */
//{-1},
{OFFSET(mii1_txd3), (MODE(3) | PULLUP_EN | RXACTIVE)}, /* UART4_RXD */
{OFFSET(mii1_txd2), (MODE(3) | PULLUDEN)}, /* UART4_TXD */
{-1},
};

0 Kemal R. Shakir over 7 years ago in reply to khageswararao bongu

TI__Guru 55345 points

Then change the instdout-path to &uart4 in <Processor SDK>/board-support/u-boot-<version>/arch/arm/dts/am335x-evmsk.dts

0 khageswararao bongu over 7 years ago in reply to Kemal R. Shakir

Expert 1380 points

thanks kemal. now it's working
changes in <Processor SDK>/board-support/u-boot-<version>/arch/arm/dts/am335x-evmsk.dts

1.modified stdout-path = &uart0; to stdout-path = &uart4;
2.add below pinmux for uart4

uart4_pins: pinmux_uart4_pins {
pinctrl-single,pins = <
0x11C (PIN_INPUT_PULLUP | MUX_MODE3) /* uart4rxd.uart0_rxd */
0x120 (PIN_OUTPUT_PULLDOWN | MUX_MODE3) /* uart4txd.uart0_txd */
>;
};
&uart4 {
pinctrl-names = "default";
pinctrl-0 = <&uart4_pins>;

status = "okay";
};

3.dissable mac supportt (i am using same pins to uart4)
#if 0
&mac {
pinctrl-names = "default", "sleep";
pinctrl-0 = <&cpsw_default>;
pinctrl-1 = <&cpsw_sleep>;
dual_emac = <1>;
status = "okay";
};
#endif

4. added support to login through uart4 in rootfs
vi /etc/securetty
# Standard serial ports
ttyS0
ttyS1
ttyS2
ttyS3
ttyS4 /*added for uart4 login*/

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Linux/AM3351: Changing debug UART