Some Questions

[John Baldwin]

On Tuesday 18 October 2005 09:32 pm, Yong Ma wrote:
> ----- Original Message -----
> From: "John Baldwin" <jhb at freebsd.org>
> To: freebsd-drivers at freebsd.org
> Subject: Re: Some Questions
> Date: Tue, 18 Oct 2005 11:17:51 -0400
>
> > On Tuesday 18 October 2005 04:26 am, Yong Ma wrote:
> > > Hi everybody:
> > >
> > >
> > > I'm new here,nice to meet you all! I'm also aFreeBSD_device_driver
> > > newbie, and now I'm enaged in writting a driverfor a cryptographic
> > > accelerator card.As a preparation I read thesections of device driver
> > > in "FreeBSD Architecture Handbook",andexercised the example driver in
> > > the book.now I have several questions(maybeeasy for you but most useful
> > > for me):
> > >
> > > 1)Some drivers declares the device_open() as int device_open(dev_t
> > > dev,...),and some declare it as int device_open(struct cdev
> > > *dev,...),sometimes the first one couldn't be
> > > compliedsuccessfully,what's the difference?
> >
> > On 6.0 and later you should use 'struct cdev *dev' and on 5.x and earlier
> > 'dev_t dev'.
> >
> > > 2) if (pci_get_vendor(dev) == 0x11c1) { ...
> > >                               ~~~~~~~~how to get this number if I don't
> > > know it?
> >
> > This number is part of the chip ID in pciconf -l output.  For example, on
> > my laptop:
> >
> > pcib1 at pci0:1:0: class=0x060400 card=0x00000000 chip=0x1a318086 rev=0x04
> > hdr=0x01
> >
> > For this device, pci_get_devid(dev) would return 0x1a318086.
> > pci_get_vendor(dev) would return the 0x8086 part of that.
> >
> > > 3)Could the device on PCI slot be listed by /pciconf -l /without
> > > driver.
> >
> > You mean cutting out the pcib1 part from the line above?  You could
> > always use something like awk, sed, or cut.  For example:
> >
> > % pciconf -l | cut -d @ -f 2
> > pci0:0:0:       class=0x060000 card=0x56001558 chip=0x1a308086 rev=0x04
> > hdr=0x00
> > pci0:1:0:       class=0x060400 card=0x00000000 chip=0x1a318086 rev=0x04
> > hdr=0x01
> > pci0:29:0:      class=0x0c0300 card=0x56001558 chip=0x24828086 rev=0x02
> > hdr=0x00
> > ...
> >
> > > 4)The printf() seems not work under XWindow mode in functions like
> > > deviec_prob or device_attach,how to make it work?
> >
> > Run 'dmesg' in your Xterminal to see the messages.  Alternatively, you
> > can use the 'xconsole' program which should show the messages in its
> > window.
> >
> > > 5)If only the pseudo-device in /dev can be destroyed with
> > > destroy_dev(sc->dev0) in detach() function in a KLD driver? I can't do
> > > that!
> >
> > I'm not sure what you are asking here.  You can't leave an entry in /dev
> > around when your module is unloaded via kldunload since you would be
> > removing the devsw and devsw functions that back that device resulting in
> > a kernel panic the next time some process tried to use the /dev entry. 
> > What exact problem are you trying to solve?
>
> There is a make_dev() in the attach() in my test driver,and a destroy_dev()
> and a bus_generic_detach() in the detach(),but the later ones seems don't
> work when I unload the KLD module,while the make_dev() works properly,so as
> I load and unload the module,there are quite a few devices in /dev have the
> same name(for me they are mypci0). Several days ago,I did a driver test of
> a PSEUDO-DEVICE with the detach() works properly.I wander if it is because
> of the real HARDWARE device this time ?
>
> this is my detach() function:
>
> static int
> mypci_detach(device_t dev)
> {
>
>     struct mypci_softc *sc;
>     sc = (struct mypci_softc *) device_get_softc(dev);
>     destroy_dev(sc->dev0);
>     bus_generic_detach(dev);
>     bus_release_resource(dev, SYS_RES_IOPORT, sc->rid, sc->res);
>     printf("Mypci detached!\n");
>     return (0);
> }

Do any processes have /dev/mypci0 open when you try to kldunload?  You 
probably should maintain a count of open clients and if it is > 0, return 
EBUSY in my_pcidetach().

-- 
John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve"  =  http://www.FreeBSD.org