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vba_map_csr(9r)
NAME
  vba_map_csr - VMEbus: Maps a VMEbus address CSR area

SYNOPSIS
  io_handle_t vba_map_csr(
	  struct controller *ctlr,
	  vme_addr_t vme_address,
	  unsigned int bcnt,
	  vme_atype_t atype );

ARGUMENTS
  ctlr
      Specifies a pointer to the VMEbus device's controller data structure.

  vme_address
      Specifies the VMEbus address to map for programmed I/O (PIO) access.

  bcnt
      Specifies the size (in bytes) of the device's CSR address region.
      Typically, the bus configuration code calls this routine on the
      driver's behalf prior to calling the driver's probe() routine.  The bus
      configuration code obtains the bcnt value, for example, for the first
      CSR address from the addr1_size member of the driver's driver data
      structure.

  atype
      A bit encoded argument that specifies the address space, transfer size,
      access mode, and swap mode for mapping the device's CSR area. A table
      of valid bits appears in the DESCRIPTION section.

DESCRIPTION
  The vba_map_csr() routine maps the specified VMEbus address space to an I/O
  handle (an io_handle_t data type).

  Dense memory access typically maps large memory buffers (for example,
  graphics frame buffers) present in the A32 address space.  If you map a CSR
  area for dense memory access by specifying the VME_DENSE bit in the atype
  argument, vba_map_csr() maps the CSR area such that there are read-ahead
  side effects.	 Read accesses to dense memory are implemented as longword
  pumps.

  As the description for the atype argument stated, you can specify atype as
  the bitwise inclusive OR of the valid bits in the following table:






  _______________________________________________________________________
  Bit Category		     Value	     Meaning
  _______________________________________________________________________
  Swap mode bits	     VME_BS_NOSWAP   Specifies no byte swapping.


			     VME_BS_BYTE

					     Specifies byte swapping in
					     bytes.
			     VME_BS_WORD

					     Specifies byte swapping in
					     words.
			     VME_BS_LWORD

					     Specifies byte swapping in
					     longwords.
			     VME_BS_QUAD

					     Specifies byte swapping in
					     quadwords.
  Address space bits	     VME_A16

					     Specifies a request for the
					     16-bit address space.
			     VME_A24

					     Specifies a request for the
					     24-bit address space.
			     VME_A32

					     Specifies a request for the
					     32-bit address space.
  Transfer size bits	     VME_D08

					     Specifies a request for the
					     8-bit data size.
			     VME_D16

					     Specifies a request for the
					     16-bit data size.
			     VME_D32

					     Specifies a request for the
					     32-bit data size.
  Access mode bits	     VME_UDATA	     Specifies user data.
			     VME_UPROG	     Specifies a user program.
			     VME_SDATA	     Specifies supervisory data.
			     VME_SPROG

					     Specifies a supervisory
					     program.
  CPU allocation space bit   VME_DENSE

					     Specifies dense space
					     mapping on a platform for
					     which the default CPU
					     allocation space is sparse.
  _______________________________________________________________________

				  Table Notes

	 ·
	 Not all bus adapters support hardware byte swapping.

	 ·
	 Not all bus adapters use the transfer size.

	 ·
	 Depending on bus adapter implementation, the CPU allocation space
	 bit may not be applicable.

RETURN VALUES
  Upon successful completion, vba_map_csr() returns an I/O handle that the
  driver can use as an argument to the routines called to read and write CSRs
  and copy buffers between system memory and I/O space.	 For example, you can
  pass this returned I/O handle in calls to read_io_port() and
  write_io_port().

  If unsuccessful, vba_map_csr() returns an I/O handle of 0 (zero).









EXAMPLE
  The following code fragment shows a call to the vba_map_csr() routine to
  map a VMEbus window for programmed I/O:

       .
       .
       .

       int		 unit;				 /* Device unit number	    */
       struct controller *ctlr	= mydev_ctlr[unit];	 /* mydev controller struct */
       struct mydev_softc *sc	= &mydev_softc[unit];	 /* mydev driver struct	    */
       int		 ret_val = ESUCCESS;		 /* Completion status	    */
       vme_addr_t	 pio_vme_addr = 0x100000;	 /* VMEbus address to map   */
       u_int		 pio_vme_size = 0x10000;	 /* VMEbus byte count	    */
       vme_atype_t	 pio_vme_am = VME_A24_UDATA_D32; /* VMEbus addr modifiers   */

       .
       .
       .

       /*
	*  Map outbound to VMEbus A24 address 0x100000 for 64 KB bytes (0x10000)
	*  with an address-modifier access mode of A24 user data.  An access
	*  width of D32 is specified; however, this value may be ignored by
	*  some VMEbus adapters.
	*/
       sc->pio_handle = vba_map_csr(ctlr,
				    pio_vme_addr,
				    pio_vme_size,
				    pio_vme_am);
       if (!(sc->pio_handle)) {
	 printf("mycode: vba_map_csr routine failed\n");
	 printf("  pio_vme_addr = 0x%x pio_vme_size = 0x%x pio_vme_am = 0x%x\n",
		pio_vme_addr,
		pio_vme_size,
		pio_vme_am);
	 ret_val = EINVAL;
       }

       .
       .
       .


  The driver example chapter of Writing VMEbus Device Drivers shows how the
  dmaex example driver calls vba_map_csr() to map to the VMEbus for
  programmed I/O (PIO). See the examples of user-mode I/O to a memory-mapped
  VMEbus window and PIO data transfers in the driver example chapter.

SEE ALSO
  Data Structures: driver(9s)

  Kernel Routines: vba_unmap_csr(9r)

Index for Section 9

Alphabetical listing for V

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