Faking PCI devices?

Faking PCI devices?

[Manohar Vanga]

Hi,

I have written a simulated driver for a PCI board and am looking for a clean
way to use the driver. Currently, I am setting the PCI ids to PCI_ANY_ID and
only allowing a single probe call to go through using a global variable
(concurrency issues but I don't care for the simulation).

static int n
...
static int fake_board_probe(struct pci_dev *pdev, const struct pci_device_id
*ent)
{
    if (n == 1)
        return -1;
    n = 1;
    ...
}
static int fake_board_init(void)
{
    n = 0;
    ....
}

I want to do a cleaner job of this and wanted to write a PCI bridge driver
that actually registers the devices with the correct IDs that I need. This
also gives me the advantage of being able to register multiple devices which
is a useful for the simulation I am working on.
Can anyone point me in the right direction for this? Most of the code (eg.
struct pci_controller) seem to be architecture specific.

The code is available for anyone interested at:
https://github.com/mvanga/wbonesim

Thanks and best regards.
-- 
/manohar
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Faking PCI devices?

[Greg KH]

On Wed, May 04, 2011 at 11:39:20AM +0200, Manohar Vanga wrote:
> Hi,
> 
> I have written a simulated driver for a PCI board and am looking for a clean
> way to use the driver. Currently, I am setting the PCI ids to PCI_ANY_ID and
> only allowing a single probe call to go through using a global variable
> (concurrency issues but I don't care for the simulation).
> 
> static int n
> ...
> static int fake_board_probe(struct pci_dev *pdev, const struct pci_device_id
> *ent)
> {
> ??? if (n == 1)
> ??????? return -1;

Please return a proper error value, like -ENODEV.

> ??? n = 1;
> ??? ...
> }
> static int fake_board_init(void)
> {
> ??? n = 0;
> ??? ....
> }
> 
> I want to do a cleaner job of this and wanted to write a PCI bridge driver that
> actually registers the devices with the correct IDs that I need. This also
> gives me the advantage of being able to register multiple devices which is a
> useful for the simulation I am working on.
> Can anyone point me in the right direction for this? Most of the code (eg.
> struct pci_controller) seem to be architecture specific.

Just register your device, and then don't use any global variables to
the driver.  Put them all in your struct pci_dev private area and you
will be fine.

There's thousands of examples of this in the kernel.

hope this helps,

greg k-h