EBC peripheral, access causing Machine Check

EBC peripheral, access causing Machine Check

[Dave Cogley]

[-- Attachment #1.1: Type: text/plain, Size: 916 bytes --]

Good Afternoon,

 

I am using an AMCC 440EPx processor with an FPGA peripheral attached to the
EBC.  I am doing the entire bank configuration in the u-boot boot loader
before Linux is loaded.  I can directly read and write registers using
memory read and write (md, nm) within area 0xC0000000 to 0xC000FFFF direct
memory I/O within the context of u-boot without any faults.  When I attempt
to access any register in area 0xC000000 within the context of my Linux
device driver I get a Machine Check fault (attached text) which appears to
be an access permission violation.  I am currently running the DENX ELDK
2.6.19.2 platform that was specific to the "Sequoia" platform.

 

I have configured the EBC access permissions and control resisters as
follows for bank 1:

 

PB1CR: 0xC003C000

PB1AP: 0x80040380

 

Dave Cogley

Software Engineer

Ultra Stereo Labs, Inc.

(805) 549-0161

mailto:dcogley@uslinc.com

 


[-- Attachment #1.2: Type: text/html, Size: 3940 bytes --]

[-- Attachment #2: mcdump.txt --]
[-- Type: text/plain, Size: 1767 bytes --]

bash-3.00# 

Machine check in kernel mode.
Data Read PLB Error
OPB to PLB3: BSTAT= 0x00000000
PLB3 to PLB4: BEAR=0xffffffffffffffff BESR0=0x00000000 BESR1=0x00000000
PLB4 to PLB3: BEAR=0xfffffffffffffffd BESR0=0x00000000 BESR1=0x00000000
PLB3 to OPB: BEAR=0xffffffff BESR0=0x00000000 BESR1=0x00000000
PLB3 arbiter: BEAR=0xfffffffe ACR=0x00000000 BESR=0x00000000
PLB4 to OPB1: BEAR=0x0000000dbfffffbf BESR0=0x00000000 BESR1=0x00000000
PLB40 Arbiter: BEAR=0x00000000c0000000 ACR=0xda000000 BESR0=0x0f000000
PLB41 Arbiter: BEAR=0xfffffffffffffffc ACR=0xdb000000 BESR0=0x00000000
POB0: BEAR=0xc27e3194ffffffff BESR0=0x00000000 BESR1=0x00000000
OPB0: BEAR=0x0000000000000000 BSTAT=0x00000000
Oops: machine check, sig: 7 [#2]
NIP: D107E2D4 LR: C0069F24 CTR: 0FF40B20
REGS: c02a9f50 TRAP: 0202   Not tainted  (2.6.19.2)
MSR: 00029000 <EE,ME>  CR: 40000022  XER: 00000000
TASK = cf6c1030[268] 'banjocore' THREAD: cf1b8000
GPR00: 40044B01 CF1B9EB0 CF6C1030 00000000 CF0EF5C0 40044B01 7F95B928 0FF39D08 
GPR08: 00000000 00000000 FFFFFFE7 D1080000 80000028 10018B10 00000000 100D8ED8 
GPR16: 100C0000 00000000 100C0000 10090000 00000000 100DF660 100C7C48 00000000 
GPR24: 100D9038 00000000 100D8F58 40044B01 FFFFFFF7 CF0EF5C0 0FFBB73C 7F95B928 
NIP [D107E2D4] banjo_ioctl+0xc0/0x14c [banjodecoder]
LR [C0069F24] do_ioctl+0x80/0x84
Call Trace:
[CF1B9EB0] [00000001] 0x1 (unreliable)
[CF1B9ED0] [C0069F24] do_ioctl+0x80/0x84
[CF1B9EE0] [C0069FB4] vfs_ioctl+0x8c/0x418
[CF1B9F10] [C006A380] sys_ioctl+0x40/0x74
[CF1B9F40] [C0001C84] ret_from_syscall+0x0/0x3c
Instruction dump:
60004b00 7f850000 419e0044 3c004004 60004b01 7f850000 38600000 409eff74 
3d60d108 812bf2a4 7c0004ac 7d204c2c <0c090000> 4c00012c 38600000 91260000 
Bus error
bash-3.00# 

Re: EBC peripheral, access causing Machine Check

[Josh Boyer]

On Mon, 24 Sep 2007 12:19:01 -0700
"Dave Cogley" <dcogley@uslinc.com> wrote:

> Good Afternoon,
> 
>  
> 
> I am using an AMCC 440EPx processor with an FPGA peripheral attached to the
> EBC.  I am doing the entire bank configuration in the u-boot boot loader
> before Linux is loaded.  I can directly read and write registers using
> memory read and write (md, nm) within area 0xC0000000 to 0xC000FFFF direct
> memory I/O within the context of u-boot without any faults.  When I attempt
> to access any register in area 0xC000000 within the context of my Linux
> device driver I get a Machine Check fault (attached text) which appears to
> be an access permission violation.  I am currently running the DENX ELDK
> 2.6.19.2 platform that was specific to the "Sequoia" platform.
> 
>  
> 
> I have configured the EBC access permissions and control resisters as
> follows for bank 1:
> 
>  
> 
> PB1CR: 0xC003C000
> 
> PB1AP: 0x80040380

You need proper TLB entries set up before you can access things.  Linux
discards the MMU settings that U-Boot does.  So your driver needs to call 
ioremap on the physical address. 

Other than that, we can't help you much without your driver code.

josh

RE: EBC peripheral, access causing Machine Check

[Dave Cogley]

[-- Attachment #1: Type: text/plain, Size: 1781 bytes --]

Yes I thought it might be a problem with the TLB.  Where does the TLB
initialization take place in the Linux kernel?  I am able to access any
other peripherals on the chip as there TLB entries appear to be properly
allocated. I am remapping the physical address for all peripherals that I am
working with.  I have attached the driver code for reference.

Dave

-----Original Message-----
From: Josh Boyer [mailto:jwboyer@jdub.homelinux.org] 
Sent: Monday, September 24, 2007 4:42 PM
To: Dave Cogley
Cc: linuxppc-embedded@ozlabs.org
Subject: Re: EBC peripheral, access causing Machine Check

On Mon, 24 Sep 2007 12:19:01 -0700
"Dave Cogley" <dcogley@uslinc.com> wrote:

> Good Afternoon,
> 
>  
> 
> I am using an AMCC 440EPx processor with an FPGA peripheral attached to
the
> EBC.  I am doing the entire bank configuration in the u-boot boot loader
> before Linux is loaded.  I can directly read and write registers using
> memory read and write (md, nm) within area 0xC0000000 to 0xC000FFFF direct
> memory I/O within the context of u-boot without any faults.  When I
attempt
> to access any register in area 0xC000000 within the context of my Linux
> device driver I get a Machine Check fault (attached text) which appears to
> be an access permission violation.  I am currently running the DENX ELDK
> 2.6.19.2 platform that was specific to the "Sequoia" platform.
> 
>  
> 
> I have configured the EBC access permissions and control resisters as
> follows for bank 1:
> 
>  
> 
> PB1CR: 0xC003C000
> 
> PB1AP: 0x80040380

You need proper TLB entries set up before you can access things.  Linux
discards the MMU settings that U-Boot does.  So your driver needs to call 
ioremap on the physical address. 

Other than that, we can't help you much without your driver code.

josh

[-- Attachment #2: banjodecoder.tar.gz --]
[-- Type: application/x-gzip, Size: 4159 bytes --]