patch-2.3.41 linux/Documentation/usb/ohci-hcd.txt

• Lines: 99
• Date: Wed Dec 31 16:00:00 1969
• Orig file: v2.3.40/linux/Documentation/usb/ohci-hcd.txt
• Orig date: Thu Jan 6 12:57:47 2000

diff -u --recursive --new-file v2.3.40/linux/Documentation/usb/ohci-hcd.txt linux/Documentation/usb/ohci-hcd.txt
@@ -1,98 +0,0 @@
-
-The OHCI HCD layer is a simple but nearly complete implementation of what the
-USB people would call a HCD  for the OHCI. 
- (ISO comming soon, Bulk, INT u. CTRL transfers enabled)
-It is based on Linus Torvalds UHCI code and Gregory Smith OHCI fragments (0.03 source tree).
-The layer (functions) on top of it, is for interfacing to the alternate-usb device-drivers. 
-
-- Roman Weissgaerber <weissg@vienna.at>
-
- * v4.0 1999/08/18 removed all dummy eds, unlink unused eds, code cleanup, bulk transfers 
- * v2.1 1999/05/09 ep_addr correction, code cleanup
- * v0.2.0 1999/05/04 
- * everything has been moved into 2 files (ohci-hcd.c, ohci-hub-root.c and headers)
- * virtual root hub is now an option, 
- * memory allocation based on kmalloc and kfree now, simple Bus error handling, 
- * INT and CTRL transfers enabled, Bulk included but disabled, ISO needs completion
- * 
- * from Linus Torvalds (uhci.c): APM (not tested); hub, usb_device, bus and related stuff
- * from Greg Smith (ohci.c): better reset ohci-controller handling, hub
- * 
- * v0.1.0 1999/04/27 initial release
- 
-to remove the module try:
-rmmod usb-ohci-hcd
-
-Features:
-- virtual root hub, all basic hub descriptors and commands (state: complete) 
-  this is an option now (v0.2.0)
-  #define  CONFIG_USB_OHCI_VROOTHUB includes the virtual hub code, (VROOTHUB)
-  default is with. 
-  (at the moment: the Virtual Root Hub is included automatically)
-  
-  files: ohci-root-hub.c, ohci-root-hub.h 
- 
-
-- Endpoint Descriptor (ED) handling more static approach 
- (EDs should be allocated in parallel to the SET CONFIGURATION command and they live
- as long as the function (device) is alive or another configuration is choosen.
- In the HCD layer the EDs has to be allocated manually either by calling a subroutine
- or by sending a USB root hub vendor specific command to the virtual root hub.
- At the alternate linux usb stack EDs will be added (allocated) at their first use.
- ED will be unlinked from the HC chains if they are not bussy.
- 
- files: ohci-hcd.c ohci-hcd.h
- routines:   (do not use for drivers, use the top layer alternate usb commands instead)
- 
- int usb_ohci_add_ep(struct ohci * ohci, unsigned int ep_addr1, 
-            int interval, int load, f_handler handler, int ep_size, int speed)
-       adds an endpoint, (if the endpoint already exists some parameters will be updated)
-       
- int usb_ohci_rm_ep( ) 
-       removes an endpoint and all pending TDs of that EP
-       
-  usb_ohci_rm_function( )
-       removes all Endpoints of a function (device)
-
-- Transfer Descriptors (TD): handling and allocation of TDs is transparent to the upper layers
-  The HCD takes care of TDs and EDs memory allocation whereas the upper layers (UBSD ...) has
-  to take care of buffer allocation.
-  files: ohci-hcd.c ohci-hcd.h 
-
-  There is one basic command for all types of bus transfers (INT, BULK, ISO, CTRL):
-  
-  int ohci_trans_req(struct ohci * ohci, hcd_ed, int ctrl_len, void  *ctrl, void * data, int data_len, __OHCI_BAG lw0, __OHCI_BAG lw1)
-  
-  CTRL: ctrl, ctrl_len ... cmd buffer 
-        data, data_len ... data buffer (in or out)
-  INT, BULK:  ctrl = NULL, ctrl_len=0,
-  		data, data_len ... data buffer (in or out)
-  ISO: tbd
-
-  There is no buffer reinsertion done by the internal HCD function. 
-  (The interface layer does this for a INT-pipe on request.)
-  If you want a transfer then you have to 
-  provide buffers by sending ohci_trans_req requests. As they are queued as TDs on an ED
-  you can send as many as you like. They should come back by the callback f_handler in
-  the same order (for each endpoint, not globally) If an error occurs all
-  queued transfers of an endpoint will return unsent. They will be marked with an error status.
-  
-  e.g double-buffering for int transfers:
-
-   	ohci_trans_req(ohci, ep_addr, 0, NULL, data0, data0_len, 0,0)
-  	ohci_trans_req(ohci, ep_addr, 0, NULL, data1, data1_len, 0,0)
-  	
-  and when a data0 packet returns by the callback f_handler requeue it:
-  	ohci_trans_req(ohci, ep_addr, 0, NULL, data0, data0_len, 0,0)
-  and when a data1 packet returns by the callback f_handler requeue it:
-  	ohci_trans_req(ohci, ep_addr, 0, NULL, data1, data1_len, 0,0)
-  	
-  lw0, lw1 are private fields for upper layers for ids or fine grained handlers.
-  The alternate usb uses them for dev_id and usb_device_irq handler.
-
-
-- Done list handling: returns the requests (callback f_handler in ED) and does 
-  some error handling, root-hub request dequeuing
-  (files: ohci-done-list.c in ohci-hcd.c now(v0.2.0))
-
-