accessing pci_dev

accessing pci_dev

[Paolo]

My apologies if this is inappropriate, but I really don't know where to go for
asking this (eventually, I'd be pleased to be addressed to valuable forums or
documents).

Question:
Is there any way to access to the struct pci_dev without registering any driver?

Thanks!

Re: accessing pci_dev

[Greg KH]

On Mon, Aug 06, 2012 at 10:19:55PM +0000, Paolo wrote:
> My apologies if this is inappropriate, but I really don't know where to go for
> asking this (eventually, I'd be pleased to be addressed to valuable forums or
> documents).
> 
> Question:
> Is there any way to access to the struct pci_dev without registering any driver?

Yes, but why would you?

What problem are you trying to solve?

greg k-h

Re: accessing pci_dev

[Paolo]

Greg KH <gregkh <at> linuxfoundation.org> writes:
> 
> Yes, but why would you?
> 
> What problem are you trying to solve?
>

Thanks for responding!

Basically, I want to check the config registers before and after the driver
registration in order to make sure that the driver is not contaminating them.

And, yes, it's the very first time I'm dealing with kernel & drivers.

Re: accessing pci_dev

[Bjorn Helgaas]

On Mon, Aug 6, 2012 at 4:16 PM, Paolo <paolopiace@gmail.com> wrote:
> Basically, I want to check the config registers before and after the driver
> registration in order to make sure that the driver is not contaminating them.

The user command "lspci -x" is a good way to see raw config space.

If you don't need the driver for boot, you can build it as a module,
make sure it isn't automatically loaded (e.g., rename it temporarily),
reboot, run lspci once, load the driver module by hand, and then run
lspci again.

If you're on x86, you can also boot with the kernel option
"pci=earlydump" to see config space before any drivers touch it, even
if they're built into the kernel.

Bjorn

Re: accessing pci_dev

[Paolo]

Bjorn Helgaas <bhelgaas <at> google.com> writes:
>
> The user command "lspci -x" is a good way to see raw config space.

Sure, Thanks. But I need & want to do everything with the functions
pci_read_config_...

They need the struct pci_dev whose pointer is returned by the BIOS (or Kernel?)
as parameter of the probe function in the struct pci_driver

There must be a way to get access to each and every pci_dev without resorting to
the probe function.

That's what I'm looking fwd to know.

Regards

Re: accessing pci_dev

[Bjorn Helgaas]

On Mon, Aug 6, 2012 at 5:13 PM, Paolo <paolopiace@gmail.com> wrote:
> Bjorn Helgaas <bhelgaas <at> google.com> writes:
>>
>> The user command "lspci -x" is a good way to see raw config space.
>
> Sure, Thanks. But I need & want to do everything with the functions
> pci_read_config_...
>
> They need the struct pci_dev whose pointer is returned by the BIOS (or Kernel?)
> as parameter of the probe function in the struct pci_driver
>
> There must be a way to get access to each and every pci_dev without resorting to
> the probe function.

pci_get_device().  In arch/mn10300/unit-asb2305/pci-irq.c,
pcibios_fixup_irqs() does something similar to what you're asking for.

Re: accessing pci_dev

[Paolo]

Bjorn Helgaas <bhelgaas <at> google.com> writes:
> 
> pci_get_device().  In arch/mn10300/unit-asb2305/pci-irq.c,
> pcibios_fixup_irqs() does something similar to what you're asking for.

Thanks so much!!