ppc405ep and Ready enable in EBC0_BnAP register

[ravi.rao at rflelect.com]

Hi All,
    Our target is based on PPC405EP and we are using a TDMoIP chip on the 
peripheral bus with chipselect 2. Since the access time to the chip is not 
deterministic we are planning to use the Ready enable. By probing into 
Chipselect and ready enable bits it looks like the chip select gets 
extended untill the ready enable becomes 1 but the access crashes with a 
Bus error.
But If I just set the twt to a very high value say 20 with ready enable 
set to 0  then it works. Any pointers to understand  what is happening 
will be of great help.
####################### Screen Dump #################################
Data machine check in kernel mode.
PLB0: BEAR= 0xf8000000 ACR=   0x00000000 BESR=  0x00000000
PLB0 to OPB: BEAR= 0x01000000 BESR0= 0x00000000 BESR1= 0x00000000
Oops: machine check, sig: 7 [#5]
NIP: C90C69BC LR: C90C6AA4 CTR: 000003E0
REGS: c023ef50 TRAP: 0202   Not tainted  (2.6.21)
MSR: 00029030 <EE,ME,IR,DR>  CR: 84044408  XER: 00000007
TASK = c3fab050[666] 'cat' THREAD: c2710000
GPR00: 00000000 C2711650 C3FAB050 C2729000 C2711EAC 00000000 00000C00 
C2711EA8
GPR08: 00000000 00000040 FFFFFFFF C9400000 44044408 100A54C0 03FF9C00 
00000001
GPR16: 0000005E C01DA824 C02E7F78 C01E0C50 C2711EA8 C01E0C20 C2711EAC 
C25DC320
GPR24: C2729000 00000000 C2711F20 C90C7FF4 C2729000 C2711EA8 C2711658 
C2729000
Call Trace:
[C2711E80] [C90C6AA4]
[C2711EA0] [C009BA60]
[C2711EF0] [C0063E6C]
[C2711F10] [C00642C8]
[C2711F40] [C0002CB4]
Instruction dump:
bf210814 3b697ff4 90010834 817b006c 7c7f1b78 a00b0000 39200002 b0010008
380003ff 7c0903a6 3bc10008 7c0b4a2e <7c09f32e> 39290002 4200fff4 3c80c90c
Bus error
Thanks,
Ravishankar Govindarao
RFL Electronics Inc.
E-mail : Ravi.Rao at rflelect.com
Voice: 973.334.3100 Ext. 233
Fax: 973.334.3863
 
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