FPGA access over PCI-E on MPC8536

[Kumar Gala]

On Sep 16, 2009, at 11:17 PM, Felix Radensky wrote:

> Hi,
>
> On my custom MPC8536 based board running 2.6.31 kernel
> FPGA is connected via x2 PCI-E lane. FPGA is identified
> during PCI scan and is visible via lspci.
>
> 0000:01:00.0 Class ff00: Altera Corporation Unknown device 0004 (rev  
> 01)
>        Subsystem: Altera Corporation Unknown device 0004
>        Flags: fast devsel, IRQ 16
>        Memory at 98000000 (32-bit, non-prefetchable) [disabled]  
> [size=1M]
>        Capabilities: [50] Message Signalled Interrupts: Mask+ 64bit+  
> Queue=0/5 Enable-
>        Capabilities: [78] Power Management version 3
>        Capabilities: [80] Express Endpoint IRQ 0
>        Capabilities: [100] Virtual Channel
>
>
> However when I attempt to access FPGA memory my mmapping it in  
> userspace the read hangs. The same happens in kernel space. Does it  
> happen because FPGA memory is marked as disabled, or because FPGA  
> code is doing something wrong ?

Can you access the device in u-boot?  That would possible tell you if  
the HW is functioning or not.

> Another question is what can cause PCI device memory be marked as
> disabled.

Good question, no idea how lspci decided to print [disabled].  Take a  
look at lspci source and see :)

- k