Date: Mon, 22 Jul 1996 22:26:51 +0200 (MET DST) From: Stefan Esser <se@zpr.uni-koeln.de> To: Peter Hawkins <peter@palin.cc.monash.edu.au> Cc: freebsd-hackers@freebsd.org Subject: PCI driver Message-ID: <199607222026.WAA03971@x14.mi.uni-koeln.de> In-Reply-To: <199607201618.CAA25065@palin.cc.monash.edu.au> References: <199607201618.CAA25065@palin.cc.monash.edu.au>
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Peter Hawkins writes: > I am looking to port the cyclom driver cy to PCI - has anyone got any > tips they can send me on porting a driver from ISA to PCI generally? > Is there any documentation you can recommend? Hi! I'm the maintainer of the PCI code, and I do of course know how to port a driver to PCI. And though I had thought about writing down the necessary steps, I just didn't have the time, yet. You have to get rid of all references to the isa_device struct. The interrupt handler has got a different parameter (generally a pointer to some parameter block for the device instance that issued the interrupt, while ISA device interrupt handlers are called with a unit number). And of course you have to recognize the device in the PCI probe phase and to write the attach code, which will take care of mapping the device's registers to VM (for a memory mapped device, the prefered method for PCI devices, since not all PCI systems support the concept of I/O ports) and of registering the interrupt handler. An example of how this is done is the NE2000 driver, which I recently modified for PCI (/sys/i386/isa/if_ed.c + /sys/pci/if_ed_p.c). Just use a context diff between the pre-PCI version and the current version to see the changes to the existing ISA code and study the if_ed_p.c file for a simple example of the attach code. I haven't looked into this in detail, but I guess that converting the Cyclom driver is only a matter of half an hour ... Let me know if you have got further questions. Regards, STefan
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