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|man pages section 9: DDI and DKI Properties and Data Structures|
- USB bulk request structure
Solaris DDI specific (Solaris DDI)
A bulk request (that is, a request sent through a bulk pipe) is used to transfer large amounts of data in reliable but non-time-critical fashion. Please refer to Section 5.8 of the USB 2.0 specification for information on bulk transfers. (The USB 2.0 specification is available at www.usb.org.)
The fields in the usb_bulk_req_t are used to format a bulk request. Please see below for acceptable combinations of flags and attributes.
The usb_bulk_req_t fields are:
uint_t bulk_len; /* number of bytes to xfer */ /* Please see */ /* usb_pipe_get_max_bulk_xfer_size(9F) */ /* for maximum size */ mblk_t *bulk_data; /* the data for the data phase */ /* IN or OUT: allocated by client */ uint_t bulk_timeout; /* xfer timeout value in secs */ /* If set to zero, defaults to 5 sec */ usb_opaque_t bulk_client_private; /* Client specific information */ usb_req_attrs_t bulk_attributes; /* xfer-attributes */ /* Normal callback function, called upon completion. */ void (*bulk_cb)( usb_pipe_handle_t ph, struct usb_bulk_req *req); /* Exception callback function, for error handling. */ void (*bulk_exc_cb)( usb_pipe_handle_t ph, struct usb_bulk_req *req); /* set by USBA/HCD framework on completion */ usb_cr_t bulk_completion_reason; /* overall success status */ /* See usb_completion_reason(9S) */ usb_cb_flags_t bulk_cb_flags; /* recovery done by callback hndlr */ /* See usb_callback_flags(9S) */
Request attributes define special handling for transfers. The following attributes are valid for bulk requests:
USB framework accepts transfers where less data is received than expected.
USB framework resets pipe and clears functional stalls automatically on exception.
USB framework resets pipe automatically on exception.
Please see usb_request_attributes(9S) for more information.
Bulk transfers/requests are subject to the following constraints and caveats:
1) The following table indicates combinations of usb_pipe_bulk_xfer() flags argument and fields of the usb_bulk_req_t request argument (X = don't care).
Flags Type Attributes Data Timeout Semantics --------------------------------------------------------------- X X X ==NULL X illegal X X ONE_XFER X X illegal no sleep IN !SHORT_XFER_OK !=NULL 0 See note (A) no sleep IN !SHORT_XFER_OK !=NULL > 0 See note (B) sleep IN !SHORT_XFER_OK !=NULL 0 See note (C) sleep IN !SHORT_XFER_OK !=NULL > 0 See note (D) no sleep IN SHORT_XFER_OK !=NULL 0 See note (E) no sleep IN SHORT_XFER_OK !=NULL > 0 See note (F) sleep IN SHORT_XFER_OK !=NULL 0 See note (G) sleep IN SHORT_XFER_OK !=NULL > 0 See note (H) X OUT SHORT_XFER_OK X X illegal no sleep OUT X !=NULL 0 See note (I) no sleep OUT X !=NULL > 0 See note (J) sleep OUT X !=NULL 0 See note (K) sleep OUT X !=NULL > 0 See note (L)
2) bulk_len must be > 0. bulk_data must not be NULL.
3) Bulk_residue is set for both READ and WRITE. If it is set to 0, it means that all of the data was transferred successfully. In case of WRITE it contains data not written and in case of READ it contains the data NOT read so far. A residue can only occur because of timeout or bus/device error. (Note that a short transfer for a request where the USB_ATTRS_SHORT_XFER_OK attribute is not set is considered a device error.) An exception callback is made and completion_reason will be non-zero.
4) Splitting large Bulk xfers: Due to internal constraints, the USBA framework can only do a limited size bulk data xfer per request. A client driver may first determine this limitation by calling the USBA interface (usb_pipe_get_max_bulk_xfer_size(9F)) and then restrict itself to doing transfers in multiples of this fixed size. This forces a client driver to do data xfers in a loop for a large request, splitting it into multiple chunks of fixed size.
The bulk_completion_reason indicates the status of the transfer. See usb_completion_reason(9S) for usb_cr_t definitions.
The bulk_cb_flags are set prior to calling the exception callback handler to summarize recovery actions taken and errors encountered during recovery. See usb_callback_flags(9S) for usb_cb_flags_t definitions.
--- Callback handling ---
All usb request types share the same callback handling. See usb_callback_flags(9S) for details.
See attributes(5) for descriptions of the following attributes:
usb_alloc_request(9F), usb_pipe_bulk_xfer(9F), usb_pipe_ctrl_xfer(9F), usb_pipe_get_max_bulk_transfer_size(9F), usb_pipe_intr_xfer(9F), usb_pipe_isoc_xfer(9F), usb_callback_flags(9S), usb_completion_reason(9S), usb_ctrl_request(9S), usb_intr_request(9S), usb_isoc_request(9S), usb_request_attributes(9S)