Re: Hi,friends, the question about the u-boot and device tree?

Hi,Scott

My board is MPC8360EMDS, my bootm command is "bootm uImage ramdisk_ppc
mpc836x_mds.dtb", I used the MPC8360E_PB_K26_20071012-LTIB.iso to generate above
uImage, ramdisk_ppc,mpc836x_mds.dtb. 
 
If I fill the frequency to zero on mpc836x_mds.dts, then the linux-2.6.22 is
crashed, the output of serial is nothing. if I fill the right frequency value same
as the HRCW on mpc836x_mds.dts, the linux is normal. So I think if the frequency
is zero on mpc836x_mds.dts, the u-boot did not pass the right frequency value to
dtb.

I think maybe that we need to define some on u-boot, then the u-boot can pass the
parameter to linux dtb?


I also has another question, I modified the HRCW to config the cpu as 660/330/400
MHZ during power on, I used the "clocks" command on u-boot to see that the clock
is real 660/330/400 MHZ, then I changed the frequency value on dts to 660/330/400,
after the bootm command, the linux was not carshed after serial configuration, but
the output is random.

"
Serial: 8250/16550 driver $Revision: 1.90 $ 4 ports, IRQ sharing disabled
serial8250.0: ttyS0 at MMIO 0xe0004500 (irq = 16) is a 16550A
[output from serial is random]
"

I have config the frequency both on HRCW and devie tree is the same, why the
frequency for serial on linux is not right?  Why the 528/260/400 is Ok, the
660/330/400 has problem on serial.

Thank you very much.

From: Scott Wood <redacted>
Reply-To: 
To:  <redacted>
Subject: Re: Hi,friends, the question about the u-boot and device tree?
Date:Tue, 18 Mar 2008 13:28:41 -0500

On Thu, Mar 13, 2008 at 11:31:11PM +0800, wrote:

quoted

I make all the frequency(timebase-frequency;bus-frequency;clock-frequency)

value

quoted

on device tree file equal to zero, I think those frequency will filled by

u-boot

quoted

during bootm, but in fact, the u-boot did not fill any frequency. after bootm,
crashed. Why?

What board?  Are you using a device-tree-aware u-boot and the three-argument
form of bootm?  What sort of crash?  How do you know it's not filling in the
frequencies?

quoted

Why so many document point out that the zero value will be filled by u-boot?

Because it does. :-)
If it's not doing so on your board, that needs to be fixed.

-Scott

On Wed, Mar 19, 2008 at 09:22:08AM +0800, ???? wrote:

My board is MPC8360EMDS, my bootm command is "bootm uImage ramdisk_ppc
mpc836x_mds.dtb", I used the MPC8360E_PB_K26_20071012-LTIB.iso to generate above
uImage, ramdisk_ppc,mpc836x_mds.dtb. 

Could you try the latest upstream u-boot, dts, and kernel to see if
things are better?

If I fill the frequency to zero on mpc836x_mds.dts, 

Which frequency property?  Did you get any device-tree-related error
messages from u-boot?

I also has another question, I modified the HRCW to config the cpu as 660/330/400
MHZ during power on, I used the "clocks" command on u-boot to see that the clock
is real 660/330/400 MHZ, then I changed the frequency value on dts to 660/330/400,
after the bootm command, the linux was not carshed after serial configuration, but
the output is random.

"
Serial: 8250/16550 driver $Revision: 1.90 $ 4 ports, IRQ sharing disabled
serial8250.0: ttyS0 at MMIO 0xe0004500 (irq = 16) is a 16550A
[output from serial is random]
"

I have config the frequency both on HRCW and devie tree is the same, why the
frequency for serial on linux is not right?  Why the 528/260/400 is Ok, the
660/330/400 has problem on serial.

What are you putting in the serial nodes' clock-frequency in each case?

-Scott