2011-05-10 13:18:12     Kernel console ttyBF0 serial baud rate

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2011-05-10 13:18:12     Kernel console ttyBF0 serial baud rate


Message: 100547   


Hi Blackfin Guys,


I've read all the documentation about, and i know that the default baud rate for this project is 57600, in any case i've tried to change it to 115200 without success by setting up the kernel args "console=ttyBF0,115200"; but when the kernel boot it only send on term unreadable characters.


I'm not asking for a solution becouse i know the console args are the only parameter at kernel time that influence serial configuration.


i'm asking a way to troubleshoot this situation?


I'm using the stable release 2010R1-RC5, i'm a BF53x custom board but this is not important because the driver is always the same.


Is there someone that can help me? it's will be very appreciated.


Bests, Mauro




2011-05-10 13:25:51     Re: Kernel console ttyBF0 serial baud rate

Mike Frysinger (UNITED STATES)

Message: 100548   


read the kernel boot log from u-boot:





2011-05-10 15:51:42     Re: Kernel console ttyBF0 serial baud rate


Message: 100551   


Thanks Mike,

Hi Blackfin Guys,


the result of postmortem reading of kernel ring buffer is correct; kernel boot perfectly and arrive to the end ready for exec init :


001a46fc: 6633 3030 3030 0a30 363c 463e 6572 6965    3f00000.<6>Freei

001a470c: 676e 7520 756e 6573 2064 656b 6e72 6c65    ng unused kernel

001a471c: 6d20 6d65 726f 3a79 3720 3533 6b36 6620     memory: 7356k f

001a472c: 6572 6465 000a 0000 0000 0000 0000 0000    reed


bootargs is also correct :


001a3e3c: 2e66 2020 6f54 6174 206c 6170 6567 3a73    f.  Total pages:

001a3e4c: 3120 3036 3230 3c0a 3e35 654b 6e72 6c65     16002.<5>Kernel

001a3e5c: 6320 6d6f 616d 646e 6c20 6e69 3a65 7220     command line: r

001a3e6c: 6f6f 3d74 642f 7665 6d2f 6474 6c62 636f    oot=/dev/mtdbloc

001a3e7c: 306b 7220 2077 6165 6c72 7079 6972 746e    k0 rw earlyprint

001a3e8c: 3d6b 6573 6972 6c61 752c 7261 3074 312c    k=serial,uart0,1

001a3e9c: 3531 3032 2030 6f63 736e 6c6f 3d65 7474    15200 console=tt

001a3eac: 4279 3046 312c 3531 3032 2030 6170 696e    yBF0,115200 pani

001a3ebc: 3d63 0a33 363c 503e 4449 6820 7361 2068    c=3.<6>PID hash


but i can't imagine what strange happen to the serial, unreadable char on the term (and dosn't seems an ivalid boudrate).


Automatic boot of image at addr 0x02000000 ...

## Booting kernel from Legacy Image at 02000000 ...

   Image Name:   bf533-

   Image Type:   Blackfin Linux Kernel Image (gzip compressed)

   Data Size:    4662138 Bytes = 4.4 MiB

   Load Address: 00001000

   Entry Point:  001c7cfc

   Verifying Checksum ... OK

   Uncompressing Kernel Image ... OK

Starting Kernel at = 001c7cfc



i've tried also  with uImage from blackfin.uclinux.org (uImage-bf533-ezkit-2010R1-RC5) with the same result. :-(


If you have any other suggestion for track down the issue, please tell me.


I really appreciate your help, thanks.


Bests, Mauro




2011-05-10 15:56:15     Re: Kernel console ttyBF0 serial baud rate

Mike Frysinger (UNITED STATES)

Message: 100552   


attempting to boot a uimage on a board it was not built for is not supported.  so dont bother with the bf533-ezkit image.


verify you've set your clkin_hz value correctly in the kernel kconfig.  further, post the full bootlog, not just a few snippets.  use the "strings" command as the documentation says.




2011-05-10 17:28:30     Re: Kernel console ttyBF0 serial baud rate


Message: 100553   


Many thanks Mike for point me on the real problem, now with the correct frequency (10000000) the boot succed.


I do not have "strings" on my U-boot, for that reason i've posted only snipplet, with md.w.


Thanks, Mauro