> -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Greg Ungerer > Sent: 15 February 2007 00:35 > To: uClinux development list > Subject: Re: [uClinux-dev] Problems accessing upper half of RAM > > > Hi Phil, > > Philip Mason wrote: > > I am having trouble accessing the upper half of the RAM > connected to my 5272 Coldfire using the 2006/08/03 kernel. > > What is the target board? >
The board was based on the 5272 demo board. > > > I had it working fine by taking the default settings for the > processor and adding the things I needed (like NFS and the various > busybox commands) but when I added enough stuff that the free memory > dropped below 8MB (the chip is 16MB) telnet connectivity > would be lost > and I would have to reboot the processor. > > I would say from the symptoms it probably wasn't working, you just > hadn't used enough memory to hit the problem yet. > > > > Suspecting that the problem was related the attempting to > access the top half of the memory I wrote a program that > output the contents of the memory at 0x20000 which was the > start of the kernel binary as expected. I then modified the > program to look at 0x820000 (exactly 8MB later) and > discovered that this showed exactly the same data. > > This really sounds like your DRAM setup registers are wrong. > The uClinux kernel does not set these (*), they are setup by > your boot loader. What boot loader do you use? > > (*) Exception is if you are running a kernel directly boot/run > from ROM/Flash - but most people don't do this. I use the Colilo boot loader (with vendor set to Motorola and board set to M5272C3-16MB) and, when I looked at what was written to the SDRAM configuration register the bank address location was set to 010 (which implies that it is an 8MB RAM). Changing this to 011 (which moves the internal addresses that become SDRAM bank addresses up by one) seems to have solved the problem. I have done a quick Google to find the home of CoLILO to report this as a bug but I can't seem to find either a site or a maintainer, can anybody point me in the right direction. Thanks Phil > > > > Running 'free' showed the total amount of memory to be (16 > minus image_size)MB as I expected and I checked the address > lines to the chip (the bank select lines specifically) which > seem to be changing as I would expect (thought I have not > totally ruled out a timing error at this point). I have tried > changing the RAM size (from AUTO to 16) and RAM bus width > (from AUTO to 32) but neither of these worked. > > The RAM size config setting just sets the limits of RAM that > the kernel will use - it doesn't setup the DRAM registers. > > > > Therefore I ask if anybody knows of any settings in the > kernel that could lead to the behaviour I am seeing? > > You need to check your RAM setup in your boot loader. > > Regards > Greg > > > > -------------------------------------------------------------- > ---------- > Greg Ungerer -- Chief Software Dude EMAIL: > [EMAIL PROTECTED] > SnapGear -- a Secure Computing Company PHONE: +61 > 7 3435 2888 > 825 Stanley St, FAX: +61 > 7 3891 3630 > Woolloongabba, QLD, 4102, Australia WEB: http://www.SnapGear.com _______________________________________________ uClinux-dev mailing list [email protected] http://mailman.uclinux.org/mailman/listinfo/uclinux-dev This message was resent by [email protected] To unsubscribe see: http://mailman.uclinux.org/mailman/options/uclinux-dev _______________________________________________ uClinux-dev mailing list [email protected] http://mailman.uclinux.org/mailman/listinfo/uclinux-dev This message was resent by [email protected] To unsubscribe see: http://mailman.uclinux.org/mailman/options/uclinux-dev
