Linux: Linux/AM335X:the spl can not boot from uart0

Hi Dwarakesh,
Thanks for your quick reply.
do you mean the u-boot-spl.bin won't run if the uboot.img has been downloaded via uart0?I think the spl can load the u-boot.img from SD card.However ,I guess it don't run after it has been downloaded from uart0.
The u-boot-spl.bin which is complied from uboot 2011.09 is ok for UART boot.

Hi Xing,

Have you changed the u-boot-spl.bin to load uboot from SDCard ? If so it will be able to. Otherwise if you are using default u-boot-spl.bin which is meant for UART boot, it will expect u-boot-spl.bin

Hi Dwarakesh,

          Do you mean that the default u-boot-spl.bin won't run until the u-boot.img has been downloaded?

Hi Xing,

If it is u-boot-spl.bin for UART boot, it looks like it wont show any logs like "CCCC" or any booting logs, but it will run and wait for uboot.img to be transferred immediately. But if you have modified u-boot-spl.bin(or u-boot-spl.bin which uses MMC loading of u-boot.img), then it might give logs or load from MMC.

Hi Xing,

Check these posts:
1. e2e.ti.com/.../534961
2. e2e.ti.com/.../1963420
3. e2e.ti.com/.../2045963

Hi  Dwarakesh

      Thank you for these information!

      I have little doubt about  "If it is u-boot-spl.bin for UART boot, it looks like it wont show any logs like "CCCC" or any booting logs, but it will run and wait for uboot.img to be transferred immediately".If SPL runs,It will jump to 0x402F0400,and will call preloader_console_init function.

     Or,could you please tell me where is the code in spl about "wait for uboot.img"?

      

It is in common/spl/spl.c

function is spl_load_image() which calls spl_ymodem_load_image()

Hi Dwarakesh,
Thanks a lot!
I think the preloader_console_init() function will be called before spl_load_image() .
The log "U-Boot SPL " PLAIN_VERSION " (" U_BOOT_DATE " - " \ U_BOOT_TIME ")" should be showed before junp to spl_load_image function.
The spl maybe hang.

Hi Xing,

You are not getting that log, then yeah it could be issue with spl being hung, not proper.

Hi Dwarakesh,

        I find the uboot will hang at "bl cpu_init_cp15" in reset function of start.s file.It can't  enter the "cpu_init_cp15" function.

       However If I change the "bl cpu_init_cp15" to "b cpu_init_cp15",the "cpu_init_cp15" function can be run.

       Do you have any suggestions about it?

I dont find why it should make difference. Ideally BL means branch with Link. If it is going to come back to the caller code, then it needs to save the link address. B alone means branch, which means it is not coming back to the caller.

Hi Dwarakesh,

    yes,I know that.However,I really want to know the BL command will be failed under what conditions.

    I have tested the LDR command,and it's also OK to jump the subroutine.

    The suggestion how to debug this issue is also much helpful for me.

Hi Xing,

Are you using uboot from the latest SDK ? Are you using the same cross compiler as given in the package ? I am seeing the package having BL and it seems to be fine.

Hi Dwarakesh,

          I use the latest SDK and compile it with linaro 6.3.1.I think this issue may have nothing to do with the cross compiler.

          Because the u-boot-spl.bin which version is 2011.09 is ok for uart boot . It's compiled by the same cross compiler.

Hi Xing,

1. Did you compare the two codes, in the start.S flow ? Are they same ?
2. What happens when you compile using the processor SDK cross compiler. The behaviour is same ?

Hi Dwarakesh,
There are many differences between these two uboot versions.
I haven't used the cross compiler in SDK.Because I had installed the latest linaro cross compiler before I downloaded the linux SDK.

Hi Xing,

I think it would be a worth try to compile the uboot with the processor SDK compiler. I wanted to just know if the start.S file or the init files of AM355x in both uboot are different or same.