Device Manager Draft (incomplete)

Hi there,

Salvatore just bugged me into sending a first draft of the new device 
manager stuff. I haven't done that much yet, but it should at least 
give you an idea about some of the changes, and also the opportunity to 
comment and influence the design :-)
I also had done some more on the missing pieces on a piece of paper I 
currently can't find again... :-}
It's a bit brief, sorry for that. I've started with a test shell to be 
able to play with a few ideas, and see how it works out in the end.

-------------8<-------------

Driver API

original Be API:
init_hardware();
init_driver();
uninit_driver();
uninit_hardware();
publish_devices();
find_device();

Current device_manager API:
supports_device(parent, noConnection);
register_device(parent);
init_driver(node, userCookie, *cookie);
uninit_driver(cookie);
device_removed(node, cookie);
device_cleanup(node);
get_supported_paths(busses, devices);

+ for busses:
register_child_devices(cookie);
rescan_bus(cookie);

Device publishing via devfs node.

New API:
supports_device(parent);
register_device(parent);
init_driver(node);
	also publishes any devices/nodes with dedicated calls (ie. 
devfs_publish_device())

uninit_driver(node);
device_removed(node);
	any devices and child nodes are removed automatically

"device" in the API above refers to device_node - maybe rename it, ie. 
supports_device() to supports_device_node()?
Still left out: power management, passive driver matching, identify 
boot driver

--

Device API

init_device(deviceCookie);
	called once before one or several open() calls
uninit_device(deviceCookie);
	supposed to free deviceCookie, called when the last reference to 
the device is closed
open(deviceCookie, path, open mode, *cookie);
	deviceCookie is an object attached to the published device

close(cookie);
free(cookie);
read(cookie, pos, buffer, *length);
write(cookie, pos, buffer, *length);
ioctl(cookie, op, buffer, length);
	as in BeOS

io(cookie, io_request);
	new function to deal with I/O requests directly.

--

I/O Requests

create_io_request(buffer, length, read/write, async, user/kernel);
create_io_request_vecs(vecs, count, length, read/write, async, user/
kernel);
	creates the requests and handles copying of the scatter/gather data 
from userland

prepare_io_request(request);
	locks the requests memory and retrieves the physical pages

map_io_request(request, vecs, count);
	Returns the buffers of the I/O request mapped into kernel memory.

prepare_io_request_dma(io request, dmaResource);
	Map the I/O request to match the DMA requirements of the device.
	If needed, create a bounce buffer to be used for DMA.
get_io_request_memory_map(buffer, io request, vecs, count);
	Get the memory map of the DMA buffer for this I/O request.

complete_io_request_dma(io request, dmaResource);
	Unmaps the data, copies back data from bounce buffer if necessary.

complete_io_request(request);
	unlocks/unmaps the memory again

delete_io_request(request);

--

DMA Resource

create_dma_resource(restrictions);
	Restrictions are: transfer size, address space, alignment

dma_buffer_alloc(resource, size)
dma_buffer_free(buffer)
	Allocates or frees memory in that DMA buffer.

delete_dma_resource(resource);

-------------8<-------------

Bye,
   Axel.


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