Re: Kernel freeze on init when SDRAM is changed

Forgot to add to the description below that when the code reach to 
execute init process and freeze, i see on the JTAG a message:

- TARGET: core #0 has entered debug mode

Could that be that something wrong happens with switching cpu modes - 
first user process 'init' is maybe the time when first  the kernel will 
switch from supervisory to user mode? Is there anything that needs to be 
changed if SDRAM size and layout (number columns, rows and bus width) 
change?

Thanks.

 
> Hi,
>
> I have 2.6.19 successfully running on AT91RM9200 board with 32M SDRAM. 
> It is using NFS mount filesystem.
>
> Now I increased the size of the SDRAM to 64M (SDRAM controller 
> configuration CR= 0x2188c159 and  32-bits bus width MR=0)
> I modify the  bootloader to  support the new size  sdram and memory 
> test  is running  ok  on the bootloader and also if I use JTAG  BDI2000.
> I didn't change anything in the kernel apart of the kernel command now 
> has 'mem=64M'.
>
> When I boot the kernel in goes ok - it  mounts nfs root filesystem ok 
> but when gets to call init it just freeze. I'm sure init  function is 
> there because I use same root directory with the old board and works 
> fine.
>
> I assume the problem is the SDRAM but I look in the kernel 
> architecture code and could not find any reference to SDRAM controller 
> in case it gets initialized to some wrong value. I assume that the 
> kernel init code doesn't do anything to the SDRAM controller - it 
> expect that this is low level initialization happened in the 
> bootloader and only provided to the kernel as ram size.
>
> Any help,  suggestions  are appreciated.
> thanks
>
> Following is the print out:
>
>
> ## Booting image at 21000000 ...
>   Image Name:   2.6.19_nfs_uncomp
>   Image Type:   ARM Linux Kernel Image (uncompressed)
>   Data Size:    2396368 Bytes =  2.3 MB
>   Load Address: 20008000
>   Entry Point:  20008000
>   Verifying Checksum ... OK
> OK
>
> Starting kernel ...
>
> Linux version 2.6.19-rb01  (gcc version 3.4.4) #411 PREEMPT Tue Sep 4 
> 10:28:04 CST 2007
> CPU: ARM920T [41129200] revision 0 (ARMv4T), cr=00003177
> Memory policy: ECC disabled, Data cache writeback
> Clocks: CPU 179 MHz, master 59 MHz, main 18.432 MHz
> CPU0: D VIVT write-back cache
> CPU0: I cache: 16384 bytes, associativity 64, 32 byte lines, 8 sets
> CPU0: D cache: 16384 bytes, associativity 64, 32 byte lines, 8 sets
> Built 1 zonelists.  Total pages: 16256
> Kernel command line: root=/dev/nfs rw 
> nfsroot=192.168.0.10:/home_own/rootfs ip=192.168.0.12 
> console=ttyS0,115200 mem=64M
> AT91: 128 gpio irqs in 4 banks
> PID hash table entries: 256 (order: 8, 1024 bytes)
> Console: colour dummy device 80x30
> Dentry cache hash table entries: 8192 (order: 3, 32768 bytes)
> Inode-cache hash table entries: 4096 (order: 2, 16384 bytes)
> Memory: 64MB = 64MB total
> Memory: 62464KB available (1940K code, 392K data, 88K init)
> Mount-cache hash table entries: 512
> CPU: Testing write buffer coherency: ok
> NET: Registered protocol family 16
> SCSI subsystem initialized
> usbcore: registered new interface driver usbfs
> usbcore: registered new interface driver hub
> usbcore: registered new device driver usb
> NET: Registered protocol family 2
> IP route cache hash table entries: 512 (order: -1, 2048 bytes)
> TCP established hash table entries: 2048 (order: 1, 8192 bytes)
> TCP bind hash table entries: 1024 (order: 0, 4096 bytes)
> TCP: Hash tables configured (established 2048 bind 1024)
> TCP reno registered
> NetWinder Floating Point Emulator V0.97 (double precision)
> io scheduler noop registered
> io scheduler anticipatory registered (default)
> atmel_usart.0: ttyAT0 at MMIO 0xfefff200 (irq = 1) is a ATMEL_SERIAL
> atmel_usart.1: ttyAT1 at MMIO 0xfffc0000 (irq = 6) is a ATMEL_SERIAL
> atmel_usart.2: ttyAT2 at MMIO 0xfffc4000 (irq = 7) is a ATMEL_SERIAL
> atmel_usart.3: ttyAT3 at MMIO 0xfffc8000 (irq = 8) is a ATMEL_SERIAL
> atmel_usart.4: ttyAT4 at MMIO 0xfffcc000 (irq = 9) is a ATMEL_SERIAL
> nbd: registered device at major 43
> usbcore: registered new interface driver ub
> eth0: Link now 100-FullDuplex
> eth0: AT91 ethernet at 0xfefbc000 int=24 100-FullDuplex 
> (10:22:33:44:55:68)
> eth0: National Semiconductor DP8384i PHY
> Initializing USB Mass Storage driver...
> usbcore: registered new interface driver usb-storage
> USB Mass Storage support registered.
> usbcore: registered new interface driver libusual
> mice: PS/2 mouse device common for all mice
> TCP cubic registered
> NET: Registered protocol family 1
> NET: Registered protocol family 17
> eth0: Link now 100-FullDuplex
> eth0: Link now 100-FullDuplex
> IP-Config: Guessing netmask 255.255.255.0
> IP-Config: Complete:
>      device=eth0, addr=192.168.0.12, mask=255.255.255.0, 
> gw=255.255.255.255,
>     host=192.168.0.12, domain=, nis-domain=(none),
>     bootserver=255.255.255.255, rootserver=192.168.0.10, rootpath=
> Looking up port of RPC 100003/2 on 192.168.0.10
> Looking up port of RPC 100005/1 on 192.168.0.10
> VFS: Mounted root (nfs filesystem).
> Freeing init memory: 88K
>
>
>


-- 
Magdalena Raltcheva
Senior Software Engineer
Codan Limited
				
81 Graves Street			Voice +61 8 8305 0453       
Newton, SA 5074				Fax   +61 8 8305 0411


mailto:[email protected]

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