Thread (5 messages) 5 messages, 2 authors, 2008-12-30

RE: virtex uImage and serial ports

From: Joshua Lamorie <hidden>
Date: 2008-12-30 19:13:56

Gidday John,=0A=0AThanks for the pointer.  I think I have already gone thro=
ugh every possible page on the wiki, without finding my answer.  There are =
some great pointers however, such as http://xilinx.wikidot.com/debugging-ke=
rnel-boot-problems.  =0A=0AAs far as I can tell, if I do 'make uImage', the=
re is no code built into vmlinux that will parse the device tree and set up=
 the serial ports (at least as far as I can see with objdump -S).  When it =
boots, there is no console output and __log_buf doesn't show any serial por=
ts detected during the initialization of the serial driver.=0A=0AWhich lead=
s to my question, how does the 8250 serial driver get the information about=
 the attached serial ports from the dtb?  Which part of the code parses the=
 dtb, finds the "ns16550" and updates/builds the platform_device informatio=
n for the 8250 serial port driver?=0A=0AJoshua=0A=0AOn Tuesday, 30 December=
, 2008 13:16, "John Linn" [off-list ref] said:=0A=0A> Hi Joshua,=0A=
=0A> Have you looked at our wiki site at http://xilinx.wikidot.com as we=
=0A> quite a bit of information there.=0A> =0A> The ML405 board is a V2Pro =
chip so it should be pretty close to what you=0A> want using the default ke=
rnel config for virtex4.=0A> =0A> I haven't tested the console at 115,200 a=
s I use it at 9600.  Shouldn't=0A> be a problem, but may not hurt to stay a=
t 9600 to get it working.=0A> =0A> There are pages on the wiki about using =
u-boot with the kernel also as=0A> it sounds like that's what you're doing.=
=0A> =0A> Thanks,=0A> John=0A> =0A> =0A>> -----Original Message-----=0A>> F=
rom: linuxppc-embedded-bounces+john.linn=3Dxilinx.com@ozlabs.org=0A> [mailt=
o:linuxppc-embedded-=0A>> bounces+john.linn=3Dxilinx.com@ozlabs.org] On Beh=
alf Of Joshua Lamorie=0A>> Sent: Wednesday, December 24, 2008 3:48 PM=0A>> =
To: linuxppc-embedded@ozlabs.org=0A>> Subject: virtex uImage and serial por=
ts=0A>>=0A>> Gidday there,=0A>>=0A>> I am trying to get 2.6.27(ish) running=
 on my custom Virtex-II Pro=0A> platform (I call it Q5).  I already=0A>> ha=
ve many years of running 2.4.26 and booting from u-boot.=0A>>=0A>> The prob=
lem is getting the console running.  I have a device tree blob=0A> built an=
d loaded into memory,=0A>> and by peeking at __log_buf I can see that it is=
 reading this okay=0A> (i.e. it is correctly finding my=0A>> interrupt cont=
roller).  However, by the time it goes to mount the=0A> ramdisk as root, it=
 complains that=0A>> there is no console.=0A>>=0A>> I'm fairly certain /cho=
sen has stdout pointing to the correct UART,=0A> and the console arguments =
are=0A>> ttyS0,115200.=0A>>=0A>> In looking through the code however, I can=
not figure out how the=0A> uImage code actually initializes the=0A>> serial=
-ports for the XILINX_VIRTEX_GENERIC_BOARD.  As I understand it,=0A> the on=
ly place where=0A>> serial_console_init is called, is within platform_init,=
 and this isn't=0A> called for uImage.=0A>>=0A>> So, three questions.=0A>>=
=0A>> 1) How is the serial driver supposed to know where the platforms=0A> =
serial ports are?=0A>>=0A>> 2) If I wanted to scrap u-boot and just copy ke=
rnel/ramdisk/dtb to=0A> memory, which kernel make target=0A>> should I use?=
  dtbImage, simpleImage?=0A>>=0A>> 3) What is the best, most modern image t=
o build that should be used by=0A> u-boot?=0A>>=0A>> Thanks in advance=0A>>=
=0A>> Joshua=0A>>=0A>> p.s. I've been trying with kernel.org mainline, xili=
nx git and denx=0A> ELDK xenomai (2.6.24).  U-boot is=0A>> built from lates=
t git source.  DTS file built from XPS 9.1i with=0A> latest service packs, =
and turned=0A>> into DTB with latest dtc source from git.=0A>>=0A>>=0A>> --=
=0A>> Xiphos Technologies=0A>> (514) 847-9474 x227=0A>> (514) 848-9644 fax=
=0A>>=0A>> www.xiphos.com=0A>> ____________________________________________=
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ct the sender and delete=0A>> this communication and any copy immediately. =
Thank you.=0A>>=0A>>=0A>>=0A>> ____________________________________________=
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