Re: Device Manager Draft (incomplete)

"Salvatore Benedetto" <[email protected]> wrote:
> What I am more personally interesting in is to understand how
> subsystem are supposed to talk to each other. Especialy because of
> usb_scsi thing.
> 
> Beside describing the API, could you try and post something about how
> things fits all together? Remember about the bus factor! :-D

That was also part of the piece of paper, and I didn't get as far again 
yet :-)
In short, though, the drivers will talk to each other via the 
device_nodes.
For example, the PCI bus manager will have a device_node of its own, 
and then another device_node for each PCI device. A device_node 
consists of device attributes and a node specific API.

In the example for USB-SCSI the relevant part of the device_node tree 
would look like more or less like this:

device root
 |
PCI bus manager
 +
PCI device (ie. the bus, will provide functions like get_pci_config(), 
read8(), ...)
 |
USB bus (ie. EHCI, ...)
 |
USB bus manager
 +
USB device (ie. the mass-storage device)
 |
USB SCSI bus
 |
SCSI bus manager
+
SCSI disk
 |
SCSI cd/disk driver

I used "+" to mark the private connection between the bus manager and 
the children it publishes.
HTH,

Bye,
   Axel.


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