Linking PCI device names and drivers

Question

Hi Everyone,
I have a PCI device with a class code of "ethernet" so the name
created in the device tree is eg:
"/pci@1f,0/pci@1/ethernet@3"
I can run add_drv and attach my driver to this just fine.
But what if I had another PCI ethernet card from a different
vendor but still with a class code of "ethernet"? How would I
get one driver associated with one device and a second driver
the other? I've run add_drv with -i 'pciXXXX,X' but the
name in the device tree is still "ethernet" and therefore this
is what shows up in /etc/path_to_inst?
My attach routine will check the vendor id and device id of
the device and will fail the attach call for the "wrong"
device. If I then add_drv the second driver for the second
card, I see entries in /etc/path_to_inst with two drivers for each
"ethernet" device. Will this cause problems in the long run?
Thanks!
Janice

Answer 1

Hi
First of all the IEEE 1275 PCI Bus Binding ( which can be found at
http://playground.sun.com) clearly states that "ethernet" is one
of the "Generic Names" listed in this manual. See portion of this
document below.
a) In collections of OS drivers, avoid the use of generic names for
the drivers themselves. For example, it is generally unwise to name a
driver ethernet, since there are many different ethernet adapters with
different programming models. Using the generic name ethernet to
identify only one such driver is presumptuous.
You may go through one of these dicsussions to get more info on setting
the "compatible property" through the driver.conf file.
You may already be familiar with most of it,but it clarifies how
a Sun system differentiates between the onboard hme card and the
add on SunSwift card. Although they both use the same driver, you
can create different driver.conf files when the drivers are different
and use the compatible property field to identify the proper driver.
To Configure Driver Parameters With PCI-bus Based Systems
1.Obtain the hardware path name for the device in the device tree.
Typically this path name and the associated instance number will be
present in the /etc/path_to_inst file. For example, on a Sun Ultra 30
UPA/PCI system in which one SunSwift-PCI card is plugged in, the
/etc/path_to_inst file will have the following two entries (in
addition to entries for other devices):
"/pci@1f,4000/network@1,1" 0 "hme"
"/pci@1f,4000/pci@4/SUNW,hme@0,1" 1 "hme"
The first entry corresponds to the hme device on the motherboard.
The second entry corresponds to the hme device on the SunSwift-PCI
card.
In the previous lines:
The first part within the double quotes specifies the hardware node
name in the device tree.
The second number is the instance number.
The last part in double quotes is the driver name.
In the device path name, the last component after the last / character
and before the @ character is the device name.
The path name before the last component is the parent name.
The comma-separated numbers after the @ character at the end
represent the device and function numbers, which are together referred
to as unit-address.
To identify a PCI device unambiguously in the hme.conf file, use the
name, parent name, and the unit-address for the device. Refer to the
pci(4) man page for more information about the PCI device specs.
In the first line of the previous example:
Name = network
Parent = /pci@1f,4000
Unit-address = 1,1
In the second line in the previous example:
Name = SUNW,hme
Parent = /pci@1f,4000/pci@4
Unit-address = 0,1
2.Set the ipg1 and ipg2 parameters for the above two devices in the
/kernel/drv/hme.conf file:
name = "SUNW,hme" parent = "/pci@1f,4000" unit-address = "1,1" ipg1=10
ipg2=5;
name = "SUNW,hme" parent = "/pci@1f,4000/pci@4" unit-address = "0,1"
ipg1=20 ipg2=10;
Note that for the motherboard device, the SUNW,hme device is used even
though the path name uses the name network. The SUNW,hme device name
is the value of the compatible property for this device.
HTH
Shridhar