USBDriver_InsertTransfer (changes)
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USBDriver
» SWI Calls
» USBDriver_InsertTransfer
USBDriver_InsertTransfer
(SWI &54A42)
| Entry | |
|---|---|
| R0 | Pointer to |
| R1 | SWI number to call to vet disc format (e.g. ADFS_VetFormat) |
| R2 | Paramter in R1 to use when calling SWI |
| R3 | Format specifier |
| Exit | |
|---|---|
| R0 | Preserved |
| R1 | Preserved |
| R2 | Preserved |
| R3 | Preserved |
Use
The This purpose of this call is to fill in a disc format structure with paramters for the specified format.SWI is called by the host controller driver to notify USBDriver that a transfer has just started.
When a transfer is requested by USBDriver via the transfer entry point for that bus, the host controller should perform any hardware specific steps to start the transfer then confirm success via this SWI.
Notes
This The call use fills in the disc format structure pointed to by R0 with the ‘perfect’ parameters for the specified format, taking no account of the abilities of the available hardware that will have to perform the format. Once filled in, this intermediateSWI calls (as opposed to the vetting HC simply starting the transfer) allows USBDriver to keep bus use statistics or for the HC to schedule the transfer in a queue for later.SWI to check the format structure for achievability on the available hardware. The vetting SWI may generate an error if the format differs widely from what can be achieved; alternatively it may alter the format structure to the closest match that can be achieved. The vetting SWI then returns to this SWI, which checks whether the format block – as updated by the vetting SWI – is still an adequate match for the desired format. If it is, this SWI returns to its caller; otherwise it generates an error.
See also
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