Template Version: @(#)sac_nextcase 1.56 10/26/05 SMI
This information is Copyright 2006 Sun Microsystems, Inc.
1. Introduction
    1.1. Project/Component Working Name:
	 scsa dma enhancement
    1.2. Name of Document Author/Supplier:
	 Author:  Eric T
    1.3  Date of This Document:
	11 April, 2006
4. Technical Description

Summary
-------
This fast-track modifies the contract private interfaces introduced
through 2005/680 so that SCSA can do DMA resource allocation and
breakup on behalf of the HBA driver.  It also raises the commitment
level to evolving.

Proposal
--------

2005/680 introduced a kmem_cache mechanism which provided initial-
ized scsi_pkt's to HBA drivers.  We can take this a step further
and have SCSA handle DMA resource allocation and breakup on behalf
of the HBA driver.  The effect of this is that SCSA hands the HBA
driver an array of DMA cookies, so an HBA driver that uses this
interface does not need to bind DMA resources, manage partial DMA
mappings, etc.; it also obviates the need for the HBA driver to
provide tran_dmafree and tran_sync_pkt entry points.

This proposal removes the "tran_setup_bp" entry point and adds three
new fields to the scsi_pkt structure, which describe the number of
DMA cookies, a pointer to the DMA cookie array, etc.  Instead of
doing allocation and setup, the HBA driver examines the array of DMA
cookies in the scsi_pkt at tran_start time, and then programs them
into its DMA engine.

Man pages are attached, with changebars where it differs from
2005/680.  There are no changes to scsi_hba_attach; it is included
again for reference.

Interface Table:
----------------

exported:

INTERFACE            STABILITY                 COMMENTS

tran_setup_pkt       evolving           scsi_hba_tran_t struct member
tran_teardown_pkt    evolving           scsi_hba_tran_t struct member
tran_pkt_constructor evolving           scsi_hba_tran_t struct member
tran_pkt_destructor  evolving           scsi_hba_tran_t struct member
tran_hba_len         evolving           scsi_hba_tran_t struct member

pkt_cdblen           evolving           scsi_pkt struct member
pkt_scblen           evolving           scsi_pkt struct member
pkt_tgtlen           evolving           scsi_pkt struct member
pkt_numcookies       evolving           scsi_pkt struct member
pkt_cookies          evolving           scsi_pkt struct member
pkt_dma_flags        evolving           scsi_pkt struct member

SCSI_HBA_TRAN_CDB    evolving           scsi_hba_attach flag
SCSI_HBA_TRAN_SCB    evolving           scsi_hba_attach flag

imported:

INTERFACE            STABILITY                 COMMENTS

DDI_DMA_* flags      evolving           see ddi_dma_buf_bind_handle(9f)

Release Binding:
---------------
Minor.


6. Resources and Schedule
    6.4. Steering Committee requested information
   	6.4.1. Consolidation C-team Name:
		on
    6.5. ARC review type: FastTrack