[U-Boot-Users] A question about initialization of SDRAM
Wolfgang Denk
wd at denx.de
Thu Nov 17 16:01:48 CET 2005
In message <Tx948882797899.26592 at send2.inner-21cn.com> you wrote:
>
> I am trying to use ELDK to make a u-boot on the board with MPC852T.
"the board with MPC852T"? There is many such boards, most of them differnt.
> There is declaration of rtx in cpu/mpc8xx/fec.c:
...
> static RTXBD *rtx = NULL;
...
> I think that "rtx" should be NULL at the first time fec_init() is entered,so the rtx will be given the value.
> but after the ELDK make the u-boot, "rtx" isn't NULL at the first time fec_init() is entered, it is 0xffffffff.
What makes you think so? The code is running perfectly fine on many
boards. Which specific problem do you see?
> Before the word "memctl->memc_mbmr = 0xD0924114" in the function initdram, rtx is NULL(0x0),but after that it
> is 0xffffffff. Part of the fuction initdram is below:
Looks as if there was a bug in the SDRAM init sequence for your board.
> I wonder what happens in "memctl->memc_mbmr = 0xD0924114;",would you please explain it to me ? Thanks!
Please see the processor's User's Manual; read the memory controller
section.
Best regards,
Wolfgang Denk
--
Software Engineering: Embedded and Realtime Systems, Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
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