[U-Boot-Users] A question about initialization of SDRAM

[蔡潋滟]

		Thanks for your reply!

		I had tried several different version of ppc_8xx-gcc to build the same u-boot.Only version 3.2.1 works ok.
All the others(3.2.2, 3.3.1 and 3.3.3) have the problem that I have said before. So I think that maybe there is
something different between these versions of gcc. Would you please explain it to me? Thanks a lot.


>>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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>>
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　　　　　　　　蔡潋滟
　　　　　　　　killercai at 21cn.com
　　　　　　　　　　2005-11-24