IP Header CRC problems

[Pieter Truter]

I have ported ARM-Linux to a SA-1110 based board with 16M ram & 16M falsh with a Crystal network chip.   I used Linux-2.3.99-pre6 and wrote a device driver for the ether chip based on the existing cs89x0 driver.   The problem is that I can ping remote system from my board and the remote system reply to the ping. However, the network stack rejects the IP packet based on a bad IP header CRC claculated with ip_fast_csum() in net/ipv4/ip_input.c.   If I compare the packet on the wire against what I pass up the IP stack, it looks the same.   So it appears that my network device driver works OK. I am tracing through the network code to find the problem, but I cannot imagine that I am the first/only person using the network on an ARM system.   The weird part is that I receive & send all ARP packets perfectly.   I would appreciete any help.   Thanks.   Here is a few screens: =================   Starting kernel at address c0008000... Uncompre ............................... done, bLinux version 2.3.99-pre3-rmk3-np2 (ptruter@testlinux) (gcc version 2.95.2 19991024 (release)) #186 Tue May 9 09:51:13 PDT 2000 Architecture: Intrinsyc Surfboard On node 0 totalpages: 2048 zone(0): 2048 pages. zone(1): 0 pages. zone(2): 0 pages. On node 1 totalpages: 2048 zone(0): 2048 pages. zone(1): 0 pages. zone(2): 0 pages. Calibrating delay loop... 180.22 BogoMIPS Memory: 8MB 8MB = 16MB total Memory: 12852KB available (888K code, 442K data, 8K init) Buffer-cache hash table entries: 1024 (order: 0, 4096 bytes) Page-cache hash table entries: 4096 (order: 2, 16384 bytes) POSIX conformance testing by UNIFIX Linux NET4.0 for Linux 2.3 Based upon Swansea University Computer Society NET3.039 NET4: Unix domain sockets 1.0/SMP for Linux NET4.0. NET4: Linux TCP/IP 1.0 for NET4.0 IP Protocols: ICMP, UDP, TCP IP: routing cache hash table of 512 buckets, 4Kbytes TCP: Hash tables configured (established 1024 bind 1024) Starting kswapd v1.6 SA1100 serial driver version 1.2 ttyS0 on SA1100 UART3 (irq 17) ttyS1 on SA1100 UART1 (irq 15) pty: 256 Unix98 ptys configured RAMDISK driver initialized: 16 RAM disks of 8192K size 1024 blocksize cerf89x0:cerf89x0_probe() cerf89x0.c: (kernel 2.3.99) Russell Nelson, Andrew Morton eth0: cs8900 rev I found at 0xd8000300 , IRQ 11, programmed I/O, MAC 00:d0:ca:f1:ff:2f RAMDISK: Compressed image found at block 0 NetWinder Floating Point Emulator V0.95 (c) 1998-1999 Rebel.com VFS: Mounted root (ext2 filesystem). Freeing unused kernel memory: 8k init   Linux login:     Some Network Screens: ================= [root@Linux /root]$ ifconfig eth0    Link encap:Ethernet  HWaddr 00:D0:CA:F1:FF:2F           inet addr:192.168.0.232  Bcast:192.168.0.255  Mask:255.255.255.0           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1           RX packets:11 errors:0 dropped:0 overruns:0 frame:0           TX packets:0 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:100           Interrupt:11 Base address:0x300   [root@Linux /root]$ arp -av ? (192.168.0.25) at 00:10:4B:33:83:36 [ether] on eth0 Entries: 1      Skipped: 0      Found: 1