RE: Kernel Panic during memcpy_toio to PCI card

[Matt D. Robinson]

Yes, grab the 4.1.1 stuff from lkcd.sourceforge.net.  Let the
lkcd-general list know if you're having problems, one of us
should be able to help.

--Matt

On Fri, 1 Nov 2002, Donepudi, Suneeta wrote:
|>Matt,
|>
|>Thanks for the response, I am using a 2.4.18 kernel with
|>a busybox. This is an embedded system with the file system
|>laid out by an 'initrd.gz'. I am new to Linux. Can LKCD
|>still be used in our case ?
|>
|>
|>Suneeta
|>
|>-----Original Message-----
|>From: Matt D. Robinson [mailto:[e-mail]]
|>Sent: Friday, November 01, 2002 3:26 PM
|>To: Donepudi, Suneeta; Matt D. Robinson
|>Subject: Re: Kernel Panic during memcpy_toio to PCI card
|>
|>
|>Hey, Suneeta.  Can you try LKCD and see if you can get
|>a crash dump with it?  Also, is this 2.4 or 2.5?
|>
|>--Matt
|>
|>On Fri, 1 Nov 2002, Donepudi, Suneeta wrote:
|>|>Hi,
|>|>
|>|>I would like help in diagnosing a kernel panic while accessing a PCI
|>device.
|>|>
|>|>Everything runs fine for sometime and in about 1/2 hour I get a Kernel
|>Panic
|>|>message saying :
|>|>
|>|>"Unable to handle kernel paging request at virtual address 0xc2821000"
|>|>
|>|>Analysis with Ksymoops shows that it is happening during a memcpy_toio()
|>|>with the PCI card. The PCI card uses three Base Address Registers with
|>|>virtual addresses mapped as follows (after ioremap has been issued):
|>|>
|>|>BAR0 = 0xc280f000
|>|>BAR1 = 0xc2811000
|>|>BAR2 = 0xc2822000
|>|>
|>|>It seems like the kernel panic is complaining about an address which is a
|>|>combination of BAR1 (lower bytes) and BAR2 (upper bytes). It should really
|>|>be accessing the BAR1 address at the point the crash occurred.
|>|>
|>|>I put the following if-statement just before the memcpy_toio():
|>|>-----------------------------------------------------------
|>|>if (((long int)pci_bar1) == 0xc2821000)
|>|>{
|>|>	printk (KERN_ERR "Illegal address for BAR1\n");
|>|>	return -1;
|>|>}
|>|>memcpy_toio (pci_bar1, in_ptr, len);
|>|>------------------------------------------------------------
|>|>
|>|>It still caused the crash in the same manner and at the same location.
|>|>Could someone help me with pointers to where I should start looking ?
|>|>Disabling interrupts around the memcpy_toio() did not make any
|>|>difference. Is this a hardware problem with the PCI card ? We are using
|>|>a Xilinx core with out FPGA build into it.
|>|>Is there a book I could read to learn more about debugging this in the 
|>|>Kernel ?
|>|>
|>|>Thanks a bunch,
|>|>Suneeta
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