Date: Fri, 20 Aug 2004 17:53:14 +0900 From: takawata@jp.freebsd.org To: Iasen Kostov <tbyte@OTEL.net> Cc: freebsd-hackers@freebsd.org Subject: Re: How can I fake a device ? Message-ID: <200408200853.RAA05110@axe-inc.co.jp> In-Reply-To: Your message of "Fri, 20 Aug 2004 10:03:58 %2B0300." <4125A25E.4050602@OTEL.net>
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In message <4125A25E.4050602@OTEL.net>, Iasen Kostov wrote:
>>> Hi,
>>>I want to know is there a way to call *_probe (for device driver) with
>>>fake (PCI) device that does not exists in the system ?
>>>First of all a cant find how "struct device" is declared (i've searched
>>>even the compile/ dir) and second I think that I'll need to intercept
>>>pci_get_vendor and pci_get_device funcs with my own which should detect
>>>the fake device and thus will return vandor/device that I need to fake.
>>>I realy don't need anything else except _probe ...
>>>
>>>
>>
>>I have never tried such but grimpsed the PCI framework,
>>I propose the following, though I don't imagine why you want
>>to do so:
>>
>>Your driver have to contain DEVICE_IDENTIFY method
>>that calls device_add_child to allocate device_t object.
>>Then you allocate 'struct pci_devinfo' and initialize
>>pci_devinfo as you like. And you have to make your
>>driver as a module. Then a device object will show up on
>>the device tree on your system.
>>
>>You may want to have a look at pci_add_children@/sys/dev/pci/pci.c
>>
>>
>>
>I think I was not clear .. .sorry. I ment to lie the driver that some
>device (that is not realy plugged in the machine) exists. Doing so I can
>check if drivers _probe() func returns "OK"
>or not and by checking every device from /usr/share/misc/pci_vendors I
>could build device<->driver_file database.
Hmm, do you want to implement docking station or something?
This is a part of my interest.
>I've patched a bit /sys/dev/pci/pci.c like this:
>
>typedef uintptr_t *pci_fake_read_ivars_t(pcicfgregs *cfg);
>static pci_fake_read_ivars_t *pci_fake_read_ivars = NULL;
>
>int
>pci_read_ivar(device_t dev, device_t child, int which, uintptr_t *result)
>{
> struct pci_devinfo *dinfo;
> pcicfgregs *cfg = NULL;
>
> if(pci_fake_read_ivars && !strcmp("fake0", dev->nameunit)) {
> (*pci_fake_read_ivars)(cfg);
> } else {
> dinfo = device_get_ivars(child);
> cfg = &dinfo->cfg;
> }
>
>And when I load my module it will set pci_fake_read_ivars and will start
>to test drivers probe sending devices with nameunit set to "fake0" thus
>telling pci_read_ivar() to fake the return values by calling
>pci_fake_read_ivars() callback ... I think this is very messy ... I hope
>that it will work this way :)
pci_read_ivar itself will not access real hardware: cache its value and
simply use hardware register index as ivar index.
So it is enough to initialize
struct pci_devinfo then call device_set_ivar. Rather, there may be problem
when pci_cfg_save()@sys/dev/pci/pci.c is called.
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