AM335x U-boot configuration for UART

Masaki Mukawa

Prodigy 80 points

Other Parts Discussed in Thread: AM3352

Hi,

I am trying to port software on our custom board which uses AM3352.

U-boot version is u-boot-2011.09-psp04.06.00.08.

I would like to change UART channel which is used by U-boot from UART 0 to UART1.

I've modified AM335x confiuratiuon as follows:

/include/configs/am335x_evm.h

#define CONFIG_SYS_NS16550_COM1 0x44e09000 /* Base EVM has UART0 */
→

#define CONFIG_SYS_NS16550_COM1 0x48022000 /* Base EVM has UART1 */

However, no character is displayed on terminal both of UART0 and UART1.

Which point should I modified else?

I have confirmed that UART1 worked properly, since kernel did output characters on UART1 with modification of uEnv.txt.

Thank you.

Mukawa

over 12 years ago

0 Miroslav Kiradzhiyski XID over 12 years ago

TI__Mastermind 25235 points

Hi Mukawa,

There are these following lines that should initialize UART1 pins, inside <u-boot_folder>/board/ti/am335x/board.c:

#ifdef CONFIG_SERIAL2
enable_uart1_pin_mux();
#endif /* CONFIG_SERIAL2 */

I checked and CONFIG_SERIAL2 is used when you make U-Boot with the following command:

make am335x_evm_uart1

Did you try this? Please check the <u-boot_folder>/boards.cfg file for more information.

Best regards,
Miroslav

0 Masaki Mukawa over 12 years ago in reply to Miroslav Kiradzhiyski XID

Prodigy 80 points

Hi Miroslav,

Thank you for your quick reply.

I cannot find board.c under <u-boot_folder>/board/ti/am335x

Even though board.c is exist under <u-boot_folder>/arch/arm/lib , but I couldn't find calling "enable_uart1_pin_mux()" in this file.

I just have executed make am335x_evm_uart1,but I also couldn't find that rule in Makefile(attached).

# make: *** No rule to make target `am335x_evm_uart1'. Stop.

Thanks and Best Regards,

Mukawa

0 Steve Kipisz over 12 years ago in reply to Masaki Mukawa

TI__Genius 15510 points

Mukawa,

Can you update to a newer version of u-boot? The u-boot in the 05.07.00.00 SDK supports building u-boot for any of the serial ports like Miroslav described. Looking at boards.cfg you will see

am335x_evm_uart1 arm armv7 am335x ti am33xx am335x_evm:SERIAL2,CONS_INDEX=2
am335x_evm_uart2 arm armv7 am335x ti am33xx am335x_evm:SERIAL3,CONS_INDEX=3

So that typing in 'make am335x_evm_uart1' will put the console on uart1. There are build targets for all of the uarts.

Steve K.

0 Miroslav Kiradzhiyski XID over 12 years ago in reply to Masaki Mukawa

TI__Mastermind 25235 points

Hi Mukawa,

Which version of the SDK/PSP are you using? I'm using the latest which is AM335x SDK 05.07.00.00. The mentioned files are present in the latest release.

The list of configs is not inside the Makefile. It is inside <u-boot_folder>/boards.cfg (Search for "am335x" inside this file).

Here is how the options work:

For target am335x_evm_uart1 you have options: am335x_evm:SERIAL2,CONS_INDEX=2

This means that the file include/configs/am335x_evm.h will be used and the following defines will be created:

#define SERIAL2 1
#define CONS_INDEX 2

Best regards,
Miroslav

0 Masaki Mukawa over 12 years ago in reply to Steve Kipisz

Prodigy 80 points

Hi Steve,

Thank you for your comment,

Even though I had tried to update newer version and merge our modification, but that version didn't work well on our board.

Is there method to change UART channel with 04.06.00.08?

If none, I will try to update again.

Thank you,

Best Regards,

Mukawa

0 Masaki Mukawa over 12 years ago in reply to Miroslav Kiradzhiyski XID

Prodigy 80 points

Hi Miroslav

I'm using older version(V04.06.00.08) than yours as I described.

Thank you for teaching me how to configuration.

I'll try to do your method if I have been able to update to 05.07.00.00.

Thank you

Best Regards,

Mukawa

0 Steve Kipisz over 12 years ago in reply to Masaki Mukawa

TI__Genius 15510 points

Mukawa,

You have to enable the clock for uart1. In board/ti/am335x/pll.c you would want to add

        /* UART1 */
        writel(PRCM_MOD_EN, CM_PER_UART1_CLKCTRL);
        while (readl(CM_PER_UART1_CLKCTRL) != PRCM_MOD_EN);

You also have to add to arch/arm/include/asm/arch-ti81xx/cpu.h

#define CM_PER_UART1_CLKCTRL (CM_PER + 0x6C) /* UART1 */

I have not tested this, but it should work.

Steve K.

0 Masaki Mukawa over 12 years ago in reply to Steve Kipisz

Prodigy 80 points

Hi Steve,

Thank you for your answer, and sorry for reply delayed.

Now I have been able to run U-Boot on UART1 with your instruction.

Thanks for your advice.

Best Regards,

Mukawa

0 Gangadhar Gangu over 11 years ago in reply to Masaki Mukawa

Expert 1865 points

Hi steve, Mukawa,

I want to configure UART1, I've done pin-muxing. I'm using SDK 7.0 and there is no board/ti/am335x/pll.c and arch/arm/include/asm/arch-ti81xx/cpu.h. Which files and regs should I modify to do below configuration?

UA_8_DATA_BITS, /**< Size of data */
UA_1_STOP_BIT, /**< Number of stop bits */
UA_NO_PARITY, /**< Byte parity */
57600u, /**< Bit rate of uart channel */
UA_HANDSHAKE_NONE, /**< Handshake type */

Regards,

Gangadhar

0 Gangadhar Gangu over 11 years ago in reply to Gangadhar Gangu

Expert 1865 points

For uboot used setbrg and start() functions in drivers/serial/serial.c,

did reset of required uart in arch/arm/cpu/ armv7/am335x/board.c

and also made changes in drivers/serial/serial_ns16550.c and got it working.

Regards,

Gangadhar

0 Manan Patel1 over 11 years ago in reply to Gangadhar Gangu

Intellectual 390 points

Hi Gangadhar,

We are also currently using TI SDK 7 and trying to use UART1 for console output. Can you explain your changes in more detail?

From what I understood, setbrg was used to update the baud-rate. The DEFAULT_UART_BASE must be changed to reset UART1 instead of UART0. I don't understand what changes you'll need in drivers/serial/serial_ns16550.c after setting the "CONFIG_CONS_INDEX" as 2 for UART1.

Thanks,

Manan.

0 Steve Kipisz over 11 years ago in reply to Manan Patel1

TI__Genius 15510 points

For SDK 7, to build u-boot for UART1, you only need to

make am335x_evm_uart1

No other changes.

Steve K.

0 Manan Patel1 over 11 years ago in reply to Steve Kipisz

Intellectual 390 points

Hi Steve,

Thanks for the prompt response.

I should have a been a bit more specific. I'm working on the latest AM437x processor and we have the EVM board and our custom boards in lab. The custom boards use UART1, and hence the requirement.

Do you think that if I make the appropriate code changes for "am335x_evm:SERIAL2,CONS_INDEX=1" related MACROS, I should get it working on AM437x? Should there be some additional changes?

Thanks,

Manan.

0 Gangadhar Gangu over 11 years ago in reply to Manan Patel1

Expert 1865 points

Hi Manan,

In boards.cfg you should have am43xx_evm:SERIAL2, CONS_INDEX=2.

Regards,

Gangadhar

0 Manan Patel1 over 11 years ago in reply to Gangadhar Gangu

Intellectual 390 points

Thanks Gangadhar.

I will test U-Boot with these changes and update soon.

0 Viraj Mistry over 9 years ago in reply to Manan Patel1

Prodigy 240 points

Hi,

I have updated u-boot as per above comment. i.e just compile with am335x_evm_uart1 option.

But when i boot it using new u-boot then i am unable to see any boot messages on UART1.

Do i need to change any other thing ?

Regards

Viraj

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AM335x U-boot configuration for UART