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From: Wolfgang Denk <wd@denx.de>
To: Valentine Barshak <vbarshak@ru.mvista.com>
Cc: linuxppc-dev@ozlabs.org, Stefan Roese <sr@denx.de>,
	Sean MacLennan <smaclennan@pikatech.com>
Subject: Re: Strange behavior with I2C on Sequoia board
Date: Thu, 21 Aug 2008 20:45:56 +0200	[thread overview]
Message-ID: <20080821184556.C1D01248FF@gemini.denx.de> (raw)
In-Reply-To: <48AD5FD1.1090809@ru.mvista.com>

Dear Valentine Barshak,

In message <48AD5FD1.1090809@ru.mvista.com> you wrote:
> 
> U-boot thinks that all memory above the first 8MB is out of reach for 
> the kernel and puts kernel bootargs and boardinfo structure below 8MB as 
> close as possible to this limit. Including the i2c driver into the 
> kernel increases the kernel image size. So when u-boot unpacks the 
> kernel to 0x400000 (Load Address: 00400000) it overwrites the kernel 
> parameters. So when the kernel actually starts, it reads zeros instead 
> of boardinfo (and mac addresses)
> 
> The 8MB limit is set for all AMCC boards in include/configs/amcc-common.h:
> #define CFG_BOOTMAPSZ		(8 << 20) /* Initial Memory map for Linux */

See also the initrd_high environment variable to adjust the limits
without need for recompiling U-Boot.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd@denx.de
The complexity of software is an essential property, not an  acciden-
tal  one. Hence, descriptions of a software entity that abstract away
its complexity often abstract away its essence.    - Fred Brooks, Jr.

      parent reply	other threads:[~2008-08-21 18:45 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-08-20 20:55 Strange behavior with I2C on Sequoia board Steven A. Falco
2008-08-21  0:44 ` Josh Boyer
2008-08-21  3:18   ` Sean MacLennan
2008-08-21  9:51     ` Stefan Roese
2008-08-21 12:30       ` Valentine Barshak
2008-08-21 13:27         ` Steven A. Falco
2008-08-21 14:32           ` Stefan Roese
2008-08-21 14:33           ` Geert Uytterhoeven
2008-08-21 14:40             ` Stefan Roese
2008-08-21 18:45             ` Wolfgang Denk
2008-08-21 14:16         ` Stefan Roese
2008-08-21 18:45         ` Wolfgang Denk [this message]

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