PCI DMA info require

["Mandeep Singh Sandhu" <mandeep_sandhu@xxxxxxxxxxx>]

hi all,
i need some info as to how DMA is used by
PCI devices ex. an ethernet card, how DMA
fits in the whole picture. also there is a
field in the net_device struct "dma" which
holds the "DMA channel allocated by the device",
what does this mean, is a seperate DMA controller
used by each PCI device???

ne help's appreciated....

TIA
- /dev/mandeep


-----Original Message-----
From: Anandraj [mailto:arm@xxxxxxxxxxxxxxx]
Sent: Friday, March 05, 2004 9:54 AM
To: kernelnewbies-bounce@xxxxxxxxxxxx; Mandeep Singh Sandhu;
kernelnewbies@xxxxxxxxxxxx
Subject: RE: ethernet driver : how to allocate space for net_device
struct


 Hi,
 the diffrence b/w alloc_etherdev(dev) and ether_setup() is 
 the memory allocation for the device struct,
 In alloc_etherdev() u dnt have to allocate memory ,it is 
 taken care by the api,
 but in ether_setup() u hav e 2 allocate memory for the dev 
 struct  b4 u pass it on to the api
 Hope this helps
 Rgds
 Anand
 
 
> > -----Original Message-----
> > From: kernelnewbies-bounce@xxxxxxxxxxxx 
> > [mailto:kernelnewbies-bounce@xxxxxxxxxxxx]On Behalf Of 
> > Mandeep Singh Sandhu
> > Sent: Thursday, March 04, 2004 2:28 PM
> > To: kernelnewbies@xxxxxxxxxxxx
> > Subject: ethernet driver : how to allocate space for 
> net_device struct
> > 
> > 
> > hi all,
> > in my ethernet driveres intialization function, how shud
> > i allocate space for the net_device structure???
> > 
> > i have seen in 8139too.c a call to "alloc_etherdev(dev)".
> > is this the preffered way to allocate space for the net_device
> > struct. In rubini's book he has mentioned the use of
> > "ether_setup" (there is no mention of "alloc_etherdev")
> > to partially fill up the net_device struct, but this fxn
> > is not used in some real world drivers like the driver for
> > realtek card (8139too.c). where can i get info on what
> > functions like "alloc_etherdev" do???
> > 
> > TIA
> > - /dev/mandeep
> > 
> > --
> > Kernelnewbies: Help each other learn about the Linux kernel.
> > Archive:       http://mail.nl.linux.org/kernelnewbies/
> > FAQ:           http://kernelnewbies.org/faq/
> > 
> 

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