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dma(9s)


NAME

  dma - EISA/ISA: Contains DMA channel information


SYNOPSIS

  _______________________
  Member Name	Data Type
  _______________________
  channel	uint_t
  is_shared	uint_t
  xfer_size	uint_t
  timing	uint_t
  mode		uint_t
  _______________________


MEMBERS

  channel
      Specifies the DMA channel number or numbers that this EISA/ISA option
      card can use. The EISA/ISA bus configuration code sets the channel
      number to a number in the range of 0-7.

  is_shared
      Specifies whether two option cards can share the same DMA channel
      number. The EISA/ISA bus configuration code sets this member to one of
      the following values during hardware autoconfiguration:


      _____________________________________________________________
      Value   Meaning
      _____________________________________________________________
      0	      The option cards cannot share the DMA channel number.
      1	      The option cards can share the DMA channel number.
      _____________________________________________________________

  xfer_size
      Specifies the DMA data transfer width. The EISA/ISA bus configuration
      code sets this member to one of the following values during hardware
      autoconfiguration:


      _________________________________________________________
      Value   Meaning
      _________________________________________________________
      00      The DMA data transfer size is 8 bits (byte).
      01      The DMA data transfer size is 16 bits (word).
      10      The DMA data transfer size is 32 bits (longword).
      _________________________________________________________

  timing
      Specifies the bus cycle type that the DMA controller executes during
      the data transfer. The EISA/ISA bus configuration code sets this member
      to one of the following values:






      ___________________________________________________________________
      Value   Meaning
      ___________________________________________________________________
      00

	      The bus cycle type is Default. This bus cycle type is
	      compatible with ISA DMA option cards.
      01

	      The bus cycle type is Type A. This bus cycle type is used
	      with higher-performance ISA DMA option cards to achieve
	      faster data transfers.
      10

	      The bus cycle type is Type B. Like bus cycle Type A, this
	      type is used with higher-performance ISA DMA option cards
	      to achieve faster data transfers.
      11

	      The bus cycle type is Type C (burst). This bus cycle type
	      is used with DMA option cards that support EISA/ISA bus
	      cycles to achieve the fastest data transfers.
      ___________________________________________________________________

  mode
      Specifies the transfer mode.


DESCRIPTION

  The dma structure describes information related to the DMA channel. The bus
  configuration code initializes the members of the dma structure during
  hardware autoconfiguration.  Device drivers call the get_config interface
  to obtain information stored in the members of the dma data structure.


FILES

  <io/dec/eisa/eisa.h>


SEE ALSO

  Kernel Interfaces: get_config(9r)

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