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NetBSD 6.1.5 - man page for ioasic_intr_establish (netbsd section 9)

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IOASIC(9)			  BSD Kernel Developer's Manual 			IOASIC(9)

NAME
     IOASIC, ioasic_intr_establish, ioasic_intr_disestablish, ioasic_intr_evcnt,
     ioasic_attach_devs, ioasic_submatch -- baseboard I/O control ASIC for DEC TURBOchannel sys-
     tems

SYNOPSIS
     #include <sys/bus.h>
     #include <dev/tc/tcvar.h>
     #include <dev/tc/ioasicreg.h>
     #include <dev/tc/ioasicvar.h>

     void
     ioasic_intr_establish(struct device *dev, void *cookie, int level, int (*handler)(void *),
	 void *arg);

     void
     ioasic_intr_disestablish(struct device *dev, void *cookie);

     const struct evcnt *
     ioasic_intr_evcnt(struct device *dev, void *cookie);

     void
     ioasic_attach_devs(struct ioasic_softc *sc, struct ioasic_dev *ioasic_devs,
	 int ioasic_ndevs);

     int
     ioasic_submatch(struct cfdata *match, struct ioasicdev_attach_args *ia);

DESCRIPTION
     The IOASIC device provides support for the DEC proprietary IOCTL ASIC found on all DEC TUR-
     BOchannel machines with MIPS (DECstation 5000 series, excluding the 5000/200) and Alpha
     (3000-series) systems.  The IOASIC is memory-mapped into the TURBOchannel system slot to
     interface up to sixteen I/O devices.  It connects the TURBOchannel to a 16-bit wide I/O bus
     and supplies various control signals to the devices that share this bus.

     The IOASIC provides hardware DMA channels and interrupt support.  DMA transfers are between
     one and four 32-bit words (16 bytes) in length, depending on the device.  The IOASIC stores
     the data in internal data registers.  The data is transferred to and from the registers in
     16-bit words to the device.  Various interrupts are signalled on DMA pointer-related condi-
     tions.

DATA TYPES
     Drivers for devices attached to the IOASIC will make use of the following data types:

     struct ioasicdev_attach_args
	      A structure used to inform the driver of the IOASIC device properties.  It contains
	      the following members:

		      char		      iada_modname
		      tc_offset_t	      iada_offset
		      tc_addr_t 	      iada_addr
		      void		      *iada_cookie;

     struct ioasic_softc
	      The parent structure which contains at the following members which are useful for
	      drivers:

		      bus_space_tag_t	      sc_bst;
		      bus_space_handle_t      sc_bsh;
		      bus_dma_tag_t	      sc_dmat;

     struct ioasic_dev
	      A structure describing the machine-dependent devices attached to the IOASIC con-
	      taining the following members:

		      char		      *iad_modname;
		      tc_offset_t	      iad_offset;
		      void		      *iad_cookie;
		      uint32_t		      iad_intrbits;

FUNCTIONS
     ioasic_intr_establish(dev, cookie, level, handler, arg)
	      Establish an interrupt handler with device dev for the interrupt described com-
	      pletely by cookie.  The priority of the interrupt is specified by level.	When the
	      interrupt occurs the function handler is called with argument arg.

     ioasic_intr_disestablish(dev, cookie)
	      Dis-establish the interrupt handler with device dev for the interrupt described
	      complete ly cookie.

     ioasic_intr_evcnt(dev, cookie)
	      Do interrupt event counting with device dev for the event described completely by
	      cookie.

     ioasic_attach_devs(sc, ioasic_devs, ioasic_ndevs)
	      Configure each of the ioasic_ndevs devices in ioasic_devs.

     ioasic_submatch(match, ia)
	      Check that the device offset is not OASIC_OFFSET_UNKNOWN.

     The ioasic_intr_establish(), ioasic_intr_disestablish(), and ioasic_intr_evcnt() functions
     are likely to used by all IOASIC device drivers.  The ioasic_attach_devs() function is used
     by ioasic driver internally and is of interest to driver writers because it must be aware of
     your device for it to be found during autoconfiguration.

AUTOCONFIGURATION
     The IOASIC is a direct-connection bus.  During autoconfiguration, machine-dependent code
     will provide an array of struct ioasic_devs describing devices attached to the IOASIC to be
     used by the ioasic driver.  The ioasic driver will pass this array to ioasic_attach_devs()
     to attach the drivers with the devices.

     Drivers match the device using iada_modname.

     During attach, all drivers should use the parent's bus_space and bus_dma resources, and map
     the appropriate bus_space region using bus_space_subregion() with iada_offset.

DMA SUPPORT
     No additional support is provided for IOASIC DMA beyond the facilities provided by the
     bus_dma(9) interface.

     The IOASIC provides two pairs of DMA address pointers (transmitting and receiving) for each
     DMA-capable device.  The pair of address pointers point to consecutive (but not necessarily
     contiguous) DMA blocks of size IOASIC_DMA_BLOCKSIZE.  Upon successful transfer of the first
     block, DMA continues to the next block and an interrupt is posted to signal an address
     pointer update.  DMA transfers are enabled and disabled by bits inside the IOASIC status
     (CSR) register.

     The interrupt handler must update the address pointers to point to the next block in the DMA
     transfer.	The address pointer update must be completed before the completion of the second
     DMA block, otherwise a DMA overrun error condition will occur.

CODE REFERENCES
     The IOASIC subsystem itself is implemented within the file sys/dev/tc/ioasic_subr.c.
     Machine-dependent portions can be found in sys/arch/<arch>/tc/ioasic.c.

SEE ALSO
     ioasic(4), autoconf(9), bus_dma(9), bus_space(9), driver(9)

BSD					  August 6, 2000				      BSD
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