scsi_alloc_consistent_buf(9f) [sunos man page]

scsi_alloc_consistent_buf(9F)				   Kernel Functions for Drivers 			     scsi_alloc_consistent_buf(9F)

NAME

       scsi_alloc_consistent_buf - allocate an I/O buffer for SCSI DMA

SYNOPSIS

       #include <sys/scsi/scsi.h>

       struct  buf  *scsi_alloc_consistent_buf(structscsi_address*ap,  struct  buf  *bp,  size_t datalen, uint_t bflags, int (*callback)(caddr_t),
       caddr_t arg);

INTERFACE LEVEL

       Solaris DDI specific (Solaris DDI).

PARAMETERS

       ap	       Pointer to the scsi_address(9S) structure.

       bp	       Pointer to the buf(9S) structure.

       datalen	       Number of bytes for the data buffer.

       bflags	       Flags setting for the allocated buffer header. This should either be B_READ or B_WRITE.

       callback        A pointer to a callback function, NULL_FUNC or SLEEP_FUNC.

       arg	       The callback function argument.

DESCRIPTION

       scsi_alloc_consistent_buf() allocates a buffer header and the associated data buffer for direct memory access (DMA) transfer.  This  buffer
       is allocated from the iobp space, which is considered consistent memory. For more details, see ddi_dma_mem_alloc(9F) and ddi_dma_sync(9F).

       For  buffers  allocated via scsi_alloc_consistent_buf(), and marked with the PKT_CONSISTENT flag via scsi_init_pkt(9F), the HBA driver must
       ensure that the data transfer for the command is correctly synchronized before the target driver's  command  completion	callback  is  per-
       formed.

       If bp is NULL, a new buffer header will be allocated using getrbuf(9F). In addition, if datalen is non-zero, a new buffer will be allocated
       using ddi_dma_mem_alloc(9F).

       callback indicates what the allocator routines should do when direct memory access (DMA) resources are not available; the valid values are:

       NULL_FUNC       Do not wait for resources. Return a NULL pointer.

       SLEEP_FUNC      Wait indefinitely for resources.

       Other Values    callback points to a function that is called when resources may become available. callback must return either 0 (indicating
		       that  it  attempted  to	allocate resources but failed to do so), in which case it is put back on a list to be called again
		       later, or 1 indicating either success in allocating resources or indicating that it no longer cares for a retry.  The  last
		       argument arg is supplied to the callback function when it is invoked.

RETURN VALUES

       scsi_alloc_consistent_buf()  returns  a	pointer  to a buf(9S) structure on success. It returns NULL if resources are not available even if
       waitfunc was not SLEEP_FUNC.

CONTEXT

       If callback is SLEEP_FUNC, then this routine may be called only from user-level code. Otherwise, it may	be  called  from  either  user	or
       interrupt level. The callback function may not block or call routines that block.

EXAMPLES

       Example 1: Allocate a request sense packet with consistent DMA resources attached.

	  bp = scsi_alloc_consistent_buf(&devp->sd_address, NULL,
		SENSE_LENGTH, B_READ, SLEEP_FUNC, NULL);
	   rqpkt = scsi_init_pkt(&devp->sd_address,
		NULL, bp, CDB_GROUP0, 1, 0,
		PKT_CONSISTENT, SLEEP_FUNC, NULL);

       Example 2: Allocate an inquiry packet with consistent DMA resources attached.

	   bp = scsi_alloc_consistent_buf(&devp->sd_address, NULL,
		SUN_INQSIZE, B_READ, canwait, NULL);
	   if (bp) {
	    pkt = scsi_init_pkt(&devp->sd_address, NULL, bp,
		 CDB_GROUP0, 1, PP_LEN, PKT_CONSISTENT,
		 canwait, NULL);
	   }

SEE ALSO

       ddi_dma_mem_alloc(9F),  ddi_dma_sync(9F),  getrbuf(9F),	scsi_destroy_pkt(9F),  scsi_init_pkt(9F),  scsi_free_consistent_buf(9F),  buf(9S),
       scsi_address(9S)

       Writing Device Drivers

SunOS 5.10							    7 Feb 2003					     scsi_alloc_consistent_buf(9F)

scsi_alloc_consistent_buf(9F)				   Kernel Functions for Drivers 			     scsi_alloc_consistent_buf(9F)

NAME

       scsi_alloc_consistent_buf - allocate an I/O buffer for SCSI DMA

SYNOPSIS

       #include <sys/scsi/scsi.h>

       struct  buf  *scsi_alloc_consistent_buf(structscsi_address*ap,  struct  buf  *bp,  size_t datalen, uint_t bflags, int (*callback)(caddr_t),
       caddr_t arg);

INTERFACE LEVEL

       Solaris DDI specific (Solaris DDI).

PARAMETERS

       ap	       Pointer to the scsi_address(9S) structure.

       bp	       Pointer to the buf(9S) structure.

       datalen	       Number of bytes for the data buffer.

       bflags	       Flags setting for the allocated buffer header. This should either be B_READ or B_WRITE.

       callback        A pointer to a callback function, NULL_FUNC or SLEEP_FUNC.

       arg	       The callback function argument.

DESCRIPTION

       scsi_alloc_consistent_buf() allocates a buffer header and the associated data buffer for direct memory access (DMA) transfer.  This  buffer
       is allocated from the iobp space, which is considered consistent memory. For more details, see ddi_dma_mem_alloc(9F) and ddi_dma_sync(9F).

       For  buffers  allocated via scsi_alloc_consistent_buf(), and marked with the PKT_CONSISTENT flag via scsi_init_pkt(9F), the HBA driver must
       ensure that the data transfer for the command is correctly synchronized before the target driver's  command  completion	callback  is  per-
       formed.

       If bp is NULL, a new buffer header will be allocated using getrbuf(9F). In addition, if datalen is non-zero, a new buffer will be allocated
       using ddi_dma_mem_alloc(9F).

       callback indicates what the allocator routines should do when direct memory access (DMA) resources are not available; the valid values are:

       NULL_FUNC       Do not wait for resources. Return a NULL pointer.

       SLEEP_FUNC      Wait indefinitely for resources.

       Other Values    callback points to a function that is called when resources may become available. callback must return either 0 (indicating
		       that  it  attempted  to	allocate resources but failed to do so), in which case it is put back on a list to be called again
		       later, or 1 indicating either success in allocating resources or indicating that it no longer cares for a retry.  The  last
		       argument arg is supplied to the callback function when it is invoked.

RETURN VALUES

       scsi_alloc_consistent_buf()  returns  a	pointer  to a buf(9S) structure on success. It returns NULL if resources are not available even if
       waitfunc was not SLEEP_FUNC.

CONTEXT

       If callback is SLEEP_FUNC, then this routine may be called only from user-level code. Otherwise, it may	be  called  from  either  user	or
       interrupt level. The callback function may not block or call routines that block.

EXAMPLES

       Example 1: Allocate a request sense packet with consistent DMA resources attached.

	  bp = scsi_alloc_consistent_buf(&devp->sd_address, NULL,
		SENSE_LENGTH, B_READ, SLEEP_FUNC, NULL);
	   rqpkt = scsi_init_pkt(&devp->sd_address,
		NULL, bp, CDB_GROUP0, 1, 0,
		PKT_CONSISTENT, SLEEP_FUNC, NULL);

       Example 2: Allocate an inquiry packet with consistent DMA resources attached.

	   bp = scsi_alloc_consistent_buf(&devp->sd_address, NULL,
		SUN_INQSIZE, B_READ, canwait, NULL);
	   if (bp) {
	    pkt = scsi_init_pkt(&devp->sd_address, NULL, bp,
		 CDB_GROUP0, 1, PP_LEN, PKT_CONSISTENT,
		 canwait, NULL);
	   }

SEE ALSO

       ddi_dma_mem_alloc(9F),  ddi_dma_sync(9F),  getrbuf(9F),	scsi_destroy_pkt(9F),  scsi_init_pkt(9F),  scsi_free_consistent_buf(9F),  buf(9S),
       scsi_address(9S)

       Writing Device Drivers

SunOS 5.10							    7 Feb 2003					     scsi_alloc_consistent_buf(9F)