Doudts in "softc" and "device_get_softc(dev)"
aji abraham
abraham_aji at yahoo.co.in
Sat Feb 17 10:08:34 UTC 2007
hi
My name is Aji Abraham, now working with device
drivers. the word
"softc" and the function "device_get_softc(dev)"
getting confuse me a
lot. am listing some query below .. pls help me ..
Q1 In a free BSD driver Code, there are two device
depended structures
struct xx_softc {
.......
......
};
struct xx_if_softc {
.......
......
};
sizeof(struct xx_softc ) is 68
sizeof(struct xx_if_softc ) is 1186
And in device attach function
xx_attach(dev){
struct xx_softc *sc;
struct xx_if_softc *if_sc;
sc_if = device_get_softc(dev);
sc = device_get_softc(device_get_parent(dev));
sc_if-> .....
sc-> ....
.......
......
}
Both allocation uses the same function. How it
possible ? can we
access
all structure member ?
Regards
Aji Abraham
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