SPI, DMA and an i.MX31

Wolf, Rene, HRO-GP rene.wolf at mbda-systems.de
Tue Sep 22 09:22:02 EDT 2009

> Good news everyone!
[Professor Hubert J. Farnsworth]

The kernel does compile. When I tried to run it the first time, it hung
right after the start. (Just after '...booting the kernel.'). Then I
set 'CONFIG_MXC_SDMA_API' to 'n' and recompiled: worked and was booting
correct (as far as I could see). I then checked the init routine from
'sdma.c' and after some try'n'error I got that it hung on enabling the
clocks for the sdma. After a quick look in arch/arm/mach-mx3/clock.c
@ line 475 - there is the entry for sdma_clk1:
DEFINE_CLOCK(sdma_clk1, 0, MXC_CCM_CGR0, 14, NULL, &sdma_clk1, &ahb_clk)
which references its self with '&sdma_clk1', thus it hung in a loop. I
guess this is a typo an should reference 'sdma_clk2' or 'NULL' not '1'.
After changing that my system booted smoothly. If I look in '/proc' there
is a dir called 'sdma', and inside there is a file 'channels':
$ cat channels
Channel 0: MCU

It seams to be alive :-)

> Take a look at ./drivers/mmc/host/mxcmmc.c

Next will try to test the mmc driver, but I don't have an MMC/SD slot on
my board. Hopefully there is some sign of an MMC in the channels
file or so.

Thanks again :-)


Ps: @ Marc Titinger: I think you are using HTML-Mail.
Afaik they won't show up on the mailing list :-)
-> check http://david.woodhou.se/email.html #7

Rene Wolf
LFK-Lenkflugkörpersysteme GmbH
Human Resources Operations & Policy, HRO
Landshuter Straße 26, 85716 Unterschleißheim, GERMANY
Phone: +49 89 3179 8337
Fax: +49 8252 99 8964
E-Mail: rene.wolf at mbda-systems.de


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