[ECOS] Re: Reset a PCI device?

Jonathan Larmour jifl@eCosCentric.com
Sun Apr 27 19:52:00 GMT 2003

Scott Wilkinson wrote:
> Jifl,
> This is with respect to the relatively new port to the MIPS IDT79S334A
> eval board.  I suspect you are correct, that this could/should go into
> the HAL_PCI_INIT code.
> This problem should only come about when downloading the redboot_RAM
> image through the IDT bootloader.  In this case the device appears to be
> CYG_PCI_CFG_COMMAND_ACTIVE (even though eCos has not yet configured it)
> and so eCos skips some configuration, or uses the existing settings. 
> This is bad.
> I'm not sure we'll have a need, but if I put together a more appropriate
> patch I will happily pass it along.

That will be good, thanks. I think the normal way to configure this (so 
the old behaviour would continue to work for those not using the IDT 
bootloader) would be to allow multiple values of 
CYGSEM_HAL_USE_ROM_MONITOR, rather than just a boolean; and require 
developers to set that accordingly.

For example right now the IDT board allows the setting of that option to 
"Generic", "CygMon", and "GDB_stubs", as well as disabling entirely (it's 
flavor booldata, not just data). But the IDT port right now should only 
have GDB_stubs or disabled - I didn't notice that when reviewing Tim's 
patch. The proposed change to HAL_PCI_INIT would mean a new "IDT" option, 
and thus the code would be conditional on CYGSEM_HAL_USE_ROM_MONITOR_IDT.



> On Fri, 2003-04-25 at 12:40, Jonathan Larmour wrote:
>>Scott Wilkinson wrote:
>>>Indeed my problem was that the device was already initialized.  I solved
>>>it by forcing COMMAND_ACTIVE to be false by clearing the PCI Command
>>>register before calling cyg_pci_get_device_info().  Probably there is a
>>>cleaner way to do this, and I welcome suggestions.
>>I'd guess since it's a platform specific problem the cleaner approach is 
>>to do it in your HAL_PCI_INIT code in plf_io.h. If this is a public board 
>>we'd love a patch :-).

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