From: Stefan Roese <stefan.roese@esd-electronics.com>
To: u-boot@lists.denx.de
Subject: [U-Boot-Users] Q about automatic dram size detection in sdram_init()
Date: Thu, 15 Jul 2004 09:30:23 +0200 [thread overview]
Message-ID: <001501c46a3d$9705b720$0212000a@PCSTEFAN> (raw)
In-Reply-To: <20040715100012.40f5d71c00027b490053c837.188@empal.com>
SYLee!
The code works fine on all different memory configutations. This is
because of the mirroring of the written values. For example on a system
with 64MByte SDRAM a write to "ADDR_64MB" will mirror to one of the
smaller addresses and the current test will fail! So this is perfectly
OK.
Best regards,
Stefan Roese
-----Original Message-----
From: u-boot-users-admin@lists.sourceforge.net [mailto:u-boot-users-
admin at lists.sourceforge.net] On Behalf Of SYLee
Sent: Thursday, July 15, 2004 3:00 AM
To: u-boot-users at lists.sourceforge.net
Subject: [U-Boot-Users] Q about automatic dram size detection in
sdram_init()
Hi,
In cpu/ppc4xx/sdram.c, in sdram_init(), the following seems to be
wrong.
/*
* Test if 128 MByte are equipped (mirror test)
*/
*(volatile ulong *)ADDR_ZERO = MAGIC0;
*(volatile ulong *)ADDR_08MB = MAGIC1;
*(volatile ulong *)ADDR_16MB = MAGIC2;
*(volatile ulong *)ADDR_32MB = MAGIC3;
*(volatile ulong *)ADDR_64MB = MAGIC4;
if ((*(volatile ulong *)ADDR_ZERO == MAGIC0) &&
(*(volatile ulong *)ADDR_08MB == MAGIC1) &&
(*(volatile ulong *)ADDR_16MB == MAGIC2) &&
(*(volatile ulong *)ADDR_32MB == MAGIC3)) {
/*
* OK, 128MB detected -> all done
*/
return;
}
I think the following conditional expression must be inserted at if
statement:
(*(volatile ulong *)ADDR_64MB == MAGIC4)
The above case is also applied to 64MB and 32MB detection.
Thanks.
SYLee.
Get your own 200MB free email at http://www.empal.com
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next prev parent reply other threads:[~2004-07-15 7:30 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-07-15 1:00 [U-Boot-Users] Q about automatic dram size detection in sdram_init() "SYLee"
2004-07-15 7:30 ` Stefan Roese [this message]
2004-07-15 7:55 ` Wolfgang Denk
2004-07-15 8:40 ` Stefan Roese
2004-07-15 7:35 ` Wolfgang Denk
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