Follow up on 4 Gig of DDR on MPC8548E
From: Morrison, Tom <hidden>
Date: 2007-06-22 17:49:42
All, We are running into a very strange problem that I=20 am hoping someone here might have some insight upon. Setup: 1) 4 Gig of DDR RAM (at physical addresses 0-0xF_FFFF_FFFF) 2) LTIB/Linux Kernel (2.6.11++) - I know we are behind the times, but it was too risky to go with latest/greatest. 3) U-boot passes a Max MEM of 3 GIG to the kernel at boot... But, we are using on the bootcmd =3D=3D> mem=3D2 GIG + a few pages Symptoms: a) Kernel boots - but fails / and hangs when it attempts to=20 open the initial console:
quoted
EXT2-fs warning: mounting unchecked fs, running e2fsck is recommended VFS: Mounted root (ext2 filesystem). 316k init EXT2-fs error (device sda1): ext2_check_page: bad entry in directory
#2: >> unaligned directory entry - offset=3D0, inode=3D128, rec_len=3D8961,name_len=3D69
quoted
Warning: unable to open an initial console.
--- a little debugging indicates that it is trying to open the ----
--- /dev/console device - and one of first physical pages allocated ----
--- is above the 2 GIG boundary (0x80000000) ----
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3Dfurther = tests=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =20 b) if we pass a 'mem=3D2GIG' or less (even though 4 GIG of DDR) -=20 it works correctly, and we boot up normally... d) Further, If we do #b, and ioremap a physical address=20 above the 2GIG and read/write those addresses - it works..... =3D=3D> This tells me the memory is working... My gut tells me this might be something to do with the 2=20 Gig boundary and specifically a "signed" versus "unsigned"=20 address/offsets mismatch maybe somewhere in the file system?? We are debugging this - but it is painful and slow process=20 to narrow the root problem - I am hoping somebody around=20 here has some knowledge of this type of failure and can help us! All the Best~! Tom Morrison Principal S/W Engineer Empirix, Inc (www.empirix.com) tmorrison@empirix.com (781) 266 - 3567